DES MOINES TCE-0U4 SITE - Superfund Records Collections · Des Moines TCE, 0U4 BVWS Project 71400 BVWS File C.3 November 22, 1994 U.S. Environmental Protection Agency 726 Minnesota

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BLACK & VEATCH Waste Science, Inc. . s 3 . » _ / — - — 5

4717 Grand Avenue, Suite 500, P.O. Box 30240, Kansas City, Missouri 64112, (913) 339-2900 ' , , _ j , ' ^ . -^ / j /^ ^ _ •

USEPA/ARCS V Des Moines TCE, 0U4

BVWS Project 71400 BVWS File C.3

November 22, 1994

U.S. Environmental Protection Agency 726 Minnesota Avenue Kansas City, Kansas 66101

Subject: Ecological Risk Assessment

Attention: Mr. Glenn Curtis, SPFD Work Assignment Manager

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Dear Mr. Curtis:

Enclosed you will find a copy of our revised Ecological Risk Assessment for 0U4 of the Des Moines TCE site.

Please direct any technical questions to the primary author of the report, Mr. Dane Pehrman, BVWS-Philadelphia, at (215) 928-2203. If you have other project related questions, please call me at (913) 338-6656.

Very truly yours,

BLACK & VEATCH Waste Science, Inc .

C t ^ d.. UJIQ^ Craig A. Willis

cawc:\...\ecorep.ltr Enclosure

cc: Ms. Joan Dollarhide, USEPA-Cincinnati, w/enclosure Mr. Dane Pehrman, BVWS-Philadelphia, w/o enclosure

30221198

llililil Superfund

ECOLOGICAL RISK ASSESSMENT

for the

DES MOINES TCE-0U4 SITE Des Moines, lowa

Prepared iror:

U.S. Environmental Protection Agency Region Vll - Kansas City, MO

Prepared by:

BLACK & VEATCH WASTE SCIENCE, INC. Philadelphia, PA

November 22,1994

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Contents Pape N°.

1.0 Problem Formulation 1 1.1 Objectives of the BERA 1 1.2 Scope of the BERA 1 1.3 Chemicals Data Collection and Evaluation 2 1.4 Habitat Evaluation 2

1.4.1 Aquatic Habitat 3 1.4.1.1 South Pond 3 1.4.1.2 Emergent Wetlands 3 1.4.1.3 Forested Wetlands 3

1.4.3 Terrestrial Habitat 3 1.4.3.1 Upland Forest 3 1.4.3.2 Upland Open Field 4

1.4.4 Wildlife Usage 4 1.4.5 Rare, Threatened, and Endangered Species 5

1.5 Exposure Pathway and Receptor Analysis 6 1.5.1 Exposure to Species/Habitats of Concern 6

1.5.1.1 South Pond 7 1.5.1.1.1 Mallard 7

1.5.1.2 Forested Wetlands 7 1.5.1.2.1 Beaver 7 1.5.1.2.2 White-tailed deer 8

1.5.1.3 Drainage Ditch 8 1.6 Endpoints 8

1.6.1 Assessment Endpoints 8 1.6.2 Measurement Endpoints 9

1.6.2.1 Aquatic Receptor Measurement Endpoints 9 1.6.2.2 Terrestrial Receptor Measurement Endpoints 10

2.0 Exposure Assessment 11 2.1 Ecological Chemicals of Potential Concern 11 2.2 Exposure Point Concentrations 11 2.3 Exposure and Intake Assumptions 11

2.3.1 Plant Uptake 12 2.3.2 Beaver Exposure 12 2.3.3 White-Tailed Deer Exposure 12 2.3.4 Mallard Exposure 13 2.3.5 Benthic Community Exposure 13

3.0 Ecological Effects Assessment 14 3.1 Toxicity Characterization 14

Des Moines TCE Site - 0U4 Ecological Risk Assessment November 2 1 , 1994

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3.2 Toxicological Safety Factors 14 3.3 Ecological Effects Characterization . 15

3.3.1 Beaver 16 3.3.2 White-Tailed Deer 16 3.3.3 Mallard 17 3.3.4 Benthic Macroinvertebrate Community 17

4.0 Risk Characteri2:ation 18 4.1 Risks to Aquatic Wildlife 18

4.1.1 Beaver 18 4.1.2 Mallard 19 4.1.3 Benthic Macroinvertebrate Community 19

4.2 Risks to Terrestrial Wildlife 19 4.2.1 White-Tailed Deer 19

4.3 Uncertainty 19 4.3.1 Endpoint Comparison Uncertainty 20 4.3.2 Exposure Assessment Uncertainty 20 4.3.3 Ecological Effects Assessment Uncertainty 21 4.4.4 Ecological Risk Assessment Uncertainty 21

5.0 Conclusions and Ecological Significance 22 5.1 Aquatic Receptor Measurement Endpoints 22 5.2 Terrestrial Receptor Measurement Endpoints 23 5.3 General Conclusions 23 5.4 Recommendations 23

6.0 References 25


Figures and Tables

Figures

Figure 1-1. Sample and Habitat Location Map Figure 1-2. Ecological Conceptual Site Model

Tables

Table 2-1. Aldrin and Dieldrin Exposure Point Concentrations Table 2-2. Ingestion Dose Worksheet for the Beaver Table 2-3. Ingestion Dose Worksheet for the White-Tailed Deer Table 2-4. Ingestion Dose Worksheet for the Mallard

Table 3-1. Measurement Endpoints for Target Species/Communities

Table 4-1. Quotient Indices for Wildlife Table 4-2. Quotient Indices for Benthic Macroinvertebrates


1.0 Problem Formulation

A semi-quantitative baseline ecological risk assessment (BERA) has been performed

for Operable Unit 4 (0U4) of the Des Moines TCE site to determine if there is any

present or potential risk to the environment from previous site activities. This evaluation

is an assessment of baseline risk which was developed by evaluating data collected during

the 0U2 RI activities and other subsequent investigations.

1.1 Objectives of the BERA This BERA evaluates the potential risks to the environment due to releases of

contaminants at the site (USEPA, 1992). The general objective of the BERA is lo

provide the information necessary to assist in the decision-making process at remedial

sites. Specific objectives of the BERA include:

• Identify and provide analysis of baseline risks (defined as risks that might exist

if no remediation or institutional controls were applied at the site);

• Provide a basis for determining the cleanup levels of chemicals that will provide

adequate protection of public health or the environment;

1.2 Scope of the BERA The goal of this BERA is to provide information on threats to the natural

environment associated with contaminants or with actions designed to remediate the site.

The BERA is also intended to reduce the inevitable uncertainty associated with

understanding the environmental effects of a site and its remediation, and to give specific

boundaries to that uncertainty. Information provided by the BERA may be used to:

• Decide if remedial action is necessary based on ecological considerations

• Evaluate the potential ecological effects of the remedial action itself

• Provide information necessary for mitigation of the threat

• Design monitoring strategies for assessing the progress and effectiveness of

remediation

• Des Moines TCE Site - 0U4 Ecological Risk Assessment November 2 1 , 1994

• 1.3 Chemicals Data Collection and Evaluation

Ecological chemicals of potential concern (ECOPCs) may often include more

individual chemicals than the human health assessment because the screening criteria for

human health do not apply to ecological receptors.

Analytical data from surface soils and sediments was used to estimate the ecological

risks at the site. The surface soil data was grouped into wetlands data and South Pond

drainage ditch data. Sediment data was only obtained for the sediments within the South

Pond. There were two sediment samples, four wetland surface soil samples, and four

drainage ditch composite surface soils used in this BERA (BVWS, 1994; Miles Corp.,

1994). The development of the ECOPCs is addressed in detail in Section 2.0 of this

BERA.

1.4 Habitat Evaluation The Habitat Evaluation was performed in February 1994 by BLACK & VEATCH

Waste Science, Inc. (BVWS) under a TES 9 contract with the U.S. Environmental

Protection Agency - Region VII (Kansas City) (BVWS, 1994).

The study area included in this Habitat Evaluation report is shown in Figure 1-1.

The study area at the Des Moines TCE site is located within a rounded triangle formed

by railroad tracks encircling an area in the southern portion of the Dico site. This

northern portion of this study area has been developed and consists of Building 4/5, dirt

roads and parking areas, and railroad tracks. The remainder of the study area is largely

undeveloped although it has been impacted by activities at and around the Dico and

DiChem facilities. Five separate types of sub-habitat were observed on the site

including: (1) Aquatic (South Pond), (2) Emergent Wetlands, (3) Forested Wetlands, (4)

Upland Forest, and (5) Upland Open Field. The location of this habitat is shown in

Figure 1-1.

The entire study area appears to have been impacted by the widespread flooding that

occurred during the summer months of 1993. Flood marks, suspended vegetative

material, and an oily film were observed at a uniform elevation on vegetation throughout

the study area. The height of this flood line varied from four to over ten feet above the

ground, depending on the ground elevation. This flood may have caused additional

contamination from off-site sources, shifting of contamination on the site, and loss or

change of ecological habitat.

• Des Moines TCE Site - 0U4 Ecological Risk Assessment November 2 1 , 1994

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1.4.1 Aquatic Habitat

The aquatic habitat observed within the study area consists of the South Pond, the

Emergent Wetlands, and the Forested Wetlands.

1.4.1.1 South Pond. The aquatic habitat observed within the study area consists of

the South Pond. At the time of the Habitat Evaluation site visit, the South Pond was

frozen and covered with approximately 14 to 16 inches of ice and an additional eight

inches of snow during site reconnaissance efforts. As a result, very little information

concerning the physical and biological components of this habitat were obtained. The

water depth in the center of South Pond was approximately 3 feet deep. The substrate

of the pond was observed to be a very soft sediment that had a strong petroleum-like

odor.

1.4.1.2 Emergent Wetlands. The emergent wetland areas were located along the

fringes of the South Pond, around the low channel that periodically drains the pond to

the east, and in an open area at the northern corner of the low-lying areas. These

emergent wetlands were dominated by smartweeds (Polygonum spp.), cattail (Typha

latifolia), and reed canary grass (Phlaris arundinacea).

1.4.1.3 Forested Wetlands. The forested wetlands were located in a contiguous band

stretching from the southern bank of the South Pond, along the west bank, and just

around the northern corner of the pond. The dominated overstory species in the forested

wetlands were silver maple, green ash (Fraxinus pennsylvanica), white ash (Fraxinus

americana), and American elm (Ulmus americana). Dominant shrub and vine species

included red mulberry (Morus rubra), grape (Vitis sp.), and silver maple saplings.

1.4.3 Terrestrial Habitat

The terrestrial habitat observed within the study area consists of upland forest and

upland open field.

1.4.3.1 Upland Forest. There were two large blocks of upland forest located in the

study area which were dominated by different tree species and subject to different

physical conditions.

The eastern upland forest area had an overstory dominated by cottonwood (Populus

deltoides). The dominant shrub, sapling, and vine species include cottonwood saplings, )

Des Moines TCE Site • 0U4 Ecological Risk Assessment / November 2 1 , 1994 3

red mulberry, silver maple, grape, and poison ivy (Toxicodendron radicans).

Herbaceous species dominant within this area include Japanese knotweed (Polygonum

cuspidalum), blackberry (Rubussp.), wild rose (Rosa sp.), and grasses (Poacea). There

was visible evidence that this area is highly utilized by a large deer herd as a feeding,

breeding, and resting area.

The second large block of upland forest is located along the southwestern boundary

of the study area. The overstory in this upland forest was dominated by silver maple,

red maple (Acer rubrum), sugar maple (Acer saccharum), white ash, American elm, and

black cherry (Prunus serotina). The dominant shrub, sapling, and vine species include

American elm and silver maple saplings and grape. There were no herbaceous species

observed within this area.

1.4.3.2 Upland Open Field. There was one large area of upland open field located

west and south of Building 4/5 and a small strip east and south of Building 4/5. These

areas were completely void of trees, saplings, and shrubs, and contained only herbaceous

species. These species included foxtail grass (Setaria sp.), and unidentified grasses. A

dry drainage channel runs from north to south along this habitat at its eastern boundary.

1.4.4 Wildlife Usage

Wildlife observed or inferred on or near the study area included white-tailed deer

(Odocoileus virginianus), beaver (Castor canadensis), songbirds (Passeriniformes),

American crows (Corvus brachyrhynchos), housecat (Felis domesticus), and Canada

goose (Branta canadensis). No other signs of any other wildlife species were observed

during the habitat evaluation. Wildlife was observed in all habitats in the study area.

Deer were the most common wildlife species in the study area. Deer were observed

in all habitats except the aquatic habitat. Based on observation of tracks, ruts, and

bedding, the deer appear to utilize the upland forest areas for sleeping areas, feeding, and

breeding. Deer appear lo utilize the other habitat on the site to pass between forested

areas. A large portion of the eastern upland forest area appears to provide excellent

habitat for a large (10-20) deer herd. This area was almost completely covered with deer

tracks, scat, urine, ruts, and bedding areas. The vegetation in this habitat provides an

excellent food source for deer, which,generally feed on twigs, shrubs, fungi, grass, and

herbs.

Chewed trees, saplings, and a dam were evidence of a beaver population in the study

area. The chewed saplings and dam were located in an area of emergent and forested

Des Moines TCE Site - 0U4 Ecological Risk Assessment November 2 1 , 1994 4

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wetlands in the southern end of the South Pond. The dam was partially within the South

Pond. There were no tracks or recent signs of beaver in the study area. Beaver eat bark

and small twigs of maples and cottonwood, both species common near the beaver dam.

Songbirds were heard in the upland forests and forested wetlands within the study

area. Individual species could not be identified during the habitat evaluation. Songbirds

generally feed on insects and the seeds of herbaceous vegetation. There were no

songbirds observed or heard in the open field or emergent wetland areas, probably due

to a lack of cover.

Five to seven American crows were observed in the eastern forest areas, roosting

in the canopies of cottonwood trees. Crows eat earthworms, insects, agricultural crops,

and herbaceous seeds; although they will occasionally eat anything available. American

crows were not observed in the other habitats within the study area.

The tracks of a housecat were observed in the open field habitat, from the urban

areas to the north under the fence, and onto the Building 4/5 site. These tracks led to

the building itself, which may indicate that a family of feral cats is present at the site.

Feral cats generally feed on small rodents and birds. The presence of feral cats at the

site may be used to infer the presence of these prey animals at the site.

A flock of Canada geese were observed flying over the site. Canada geese usually

utilize pond and lake habitats, where they feed on leaves and tubers of emergent wetland

vegetation. The South Pond area may provide suitable grazing and resting habitat for

flocks of geese.

1.4.5 Rare, Threatened, and Endangered Species

Information collected during the site investigations did not indicate the presence of

any threatened or endangered sf>ecies on or near the site. No threatened or endangered

species were observed during the site investigations (BVWS, 1994).


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1.5 Exposure Pathway and Receptor Analysis A migration pathway is defined, for the purpose of this BERA, as a route by which

a contaminant may be transported from the site to the exposure point for a particular

wildlife species or habitat of concern. An exposure route is defined, for the purposes

of this BERA, as the means by which contaminants in a specific media enter a wildlife

species of concern.

Contaminants from the Des Moines TCE site have been shown to have migrated to

the South Pond, Forested Wetlands, and the Drainage Ditch from South Pond based on

the analysis of surface soil and sediment samples colleceted by Eckendelder (1993),

Miles Corp. (1994) and BVWS (1994).

The exposure routes for contaminants in these habitats to representative wildlife

species may include: 1) ingestion, 2) respiration, and 3) absorption. Ingestion of

contaminants occurs when an organism ingests contaminated food, water, or other

contaminated media through direct or incidental ingestion. Respiration of contaminants

occurs when an organism absorbs contaminants through the respiratory organs such as

the skin, gills, or lungs. Contaminants are also absorbed directly through the skin, eyes,

and other mucous membranes.

Data are lacking concerning the inhalation and absorption exposure and uptake rates

for chemicals in wildlife species. Therefore, in this BERA, the exposure of wildlife lo

contaminants will be solely based on the direct and incidental ingestion of contaminated

media and food by the wildlife species of concern. Since surface water samples were not

evaluated in this BERA, direct and incidental ingestion of contaminated water will not

be assessed in this BERA. As a result of these factors, the BERA will only address the

direct and incidental ingestion of contaminated sediments and soil from each habitat, and

may underesdmate the overall risks to those species of concern.

1.5.1 Exposure to Species/Habitats of Concern

Based on the findings of the habitat evaluation and the environmental analytical data

available at the site, there were three habitats of concern evaluated in this BERA

including the South Pond, the Forested Wetlands, and the Drainage Ditch. The potential

exposure to actual or surrogate species indicative of the most critical trophic feeding

groups was modelled for each habitat of concem.

No samples of vegetation were analyzed, therefore, concentrations of ECOPCs in

these organisms are unknown. However, as essential points of potential ECOPC

Des Moines TCE Site • 0U4 Ecological Risk Assessment November 2 1 , 1994

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exposure in the food chain, it becomes essential to predict the concentrations of ECOPCs

in these organisms based on the known sediment concentrations.

For vegetation, the amount of a contaminant can be estimated based on the soil or

sediment concentration and the chemical properties of each particular chemical. The

vegetation bioconcentration factor is inversely proportional to the square root of the

octanol-water coefficient for each ECOPC (Travis, 1988).

A graphical representation of the relationship between the contaminated surface soils

and sediments and the wildlife species of concern is presented in the ecological

conceptual model shown in Figure 1-2.

1.5.1.1 South Pond. The South Pond is a generally stagnant aquatic habitat

represented by both grazer and detritus food chains. The detritus food chain will be

evaluated by direct comparison of contaminant concentrations in sediments to benthic

toxicity data. The mallard, an omnivore representing the grazer food chain, will be used

to model exposure to contaminated South Pond sediments.

1.5.1.1.1 Mallard. The mallard (Anas platyrhynchos), an omnivorous bird, will

be used to determine the exposure of omnivores to contaminated sediments and

vegetation in the South Pond (EPA, 1993). The mallard is commonly found in

ponds, lakes, and marshes (Bull and Farrand, 1988). The mallard feeds primarily

on green vegetation, aquatic roots and tubers, seeds, snails, and benthic invertebrates

by dabbling and filtering through soft sediments (EPA, 1993); however, only

vegetation ingestion and incidental soil ingestion were examined in this BERA.

There is limited information addressing invertebrate and insect uptake and

bioaccumulation of contaminants; therefore, an accurate determination of the

contaminate dose from this portion of the diet would not be practical.

1.5.1.2 Forested Wetlands. The Forested Wetland is primarily carnivore/grazer

habitat; however, there are no known carnivorous species present on the site. These

areas, in the case of this site, are more accurately represented by the grazer food chain.

Accordingly, the beaver and the white-tailed deer were selected as wildlife species of

concern subject to exposure to contaminated surface soils in the wetland.

1.5.1.2.1 Beaver. The beaver (Castor canadensis), a herbivorous, semi-aquatic

mammal, will be used to determine the exposure of herbivores to contaminated


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sediments in the Forested Wetland. One beaver lodge was observed in the

southeastern portion of South Pond, in the Forested Wetland area. Additionally,

there was evidence observed on trees that the beaver feeds in this area. The beaver

may also feed on roots and tubers of emergent vegetation growing around the South

Pond.

1.5.1.2.2 White-tailed deer. The white-tailed deer (Odocoileus virginianus), a

herbivorous, terrestrial mammal, was used to determine the exposure of terrestrial

herbivores to contaminated sediments in the Forested Wetland. The white-tailed

deer may spend a portion of its time feeding on shrubs, grasses, and leaves in

wetlands and uplands. There was evidence of an abundant deer population observed

during the site investigation.

1.5.1.3 Drainage Ditch. The Drainage Ditch is part of the Upland Open Field

habitat, which is primarily a carnivore/grazer habitat; however, there are no known

carnivorous species present on the site. These areas, in the case of this site, are more

accurately represented by the grazer food chain. Accordingly, the white-tailed deer was

selected as wildlife species of concern subject to exposure to contaminated ditch soils.

The habitat requirements and habitat area are discussed in Section 1.5.1.2.2.

1.6 Endpoints

The ecological significance of the various habitats and wildlife species of concern

will be examined and appropriate goals or assessment endpoints for that value will be

determined. After determining the appropriate assessment endpoints, functional

measurement endpoints will be chosen to represent these cissessment endpoints.

1.6.1 Assessment Endpoints

Assessment endpoints are those describing the effects that drive decision making,

such as reduction of key populations or disruption of community structure. Assessment

endpoints for an ecological risk assessment must be capable of being represented by

quantifiable measurement endpoints. They must also be protective of the value of the

various habitats of concem. With this in mind, the assessment endpoints chosen for 0U4

of the Des Moines TCE site are:


South Pond

Omnivorous Species Viability

Macroinvertebrate Community Viability

Forested Wetlands

Herbivorous Species Viability

Drainage Ditch


Loss of species and community viability is defined for the purposes of this

investigation as the loss of any species or group of species due to the direct or indirect

effects of a release of substances from the site.

1.6.2 Measurement Endpoints Measurement endpoints are those used in the field to approximate represent or lead

to the assessment endpoint. Because the direct measurement endpoint of habitat diversity

is incapable of being protective of the habitat until after the quantifiable degradation has

occurred, it proves an inadequate endpoint for the purposes of this study. Rather, the

most convenient expression of risk should be a probability that such an event will occur

or a simple quotient index (Ql) developed from a comparison of exposure doses or

concentrations to the toxicity information available for each chemical. This toxicity

information will be the measurement endpoint for the BERA.

1.6.2.1 Aquatic Receptor Measurement Endpoints. Aquatic habitats present

include the Forested Wetland and the South Pond. The measurement endpoint to be used

in evaluating the effects of ECOPCs on the viability of the benthic community will be

the NOAA Effects Range-Low (ER-L) screening values for aquatic sediments (USEPA,

1991). The maximum concentration of ECOPCs in sediments will be compared to the

measurement endpoint to determine if the concentrations of ECOPCs are protective of

total benthic community viability for the South Pond.

The measurement endpoint, to be used in evaluating the effects of ECOPCs on the

viability of the target wildlife species, will include Toxicity Reference Values (TRV)

developed from No-Observable-Adverse-Effect-Level(NOAELs) or Lowest-Observable-

Des Moines TCE Site - 0U4 Ecological Risk Assessment / November 2 1 , 1994 9

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Adverse-Effect-Levels (LOAELs) obtained from the Integrated Risk Information System

(IRIS, 1993) or other lexicological data in the literature. Total exposure of the wildlife

species of concern (beaver, white-tailed deer, and the mallard) to ECOPCs in surflcial

soils and sediments will be determined by estimating the chronic daily intake (CDI) dose.

This CDI will be compared to the TRV to determine if the ECOPC concentrations are

protective of species viability for the wildlife species of concern.

1.6.2.2 Terrestrial Receptor Measurement Endpoints. Terrestrial habitats present

include the South Pond drainage ditch of the Des Moines TCE site. The measurement

endpoint, to be used in evaluating the effects of ECOPCs on the viability of the target

wildlife species, will include Toxicity Reference Values (TRV) developed from No-

Observable-Adverse-Effect-Level (NOAELs) or Lowest-Observable-Adverse-Effect-

Levels (LOAELs) obtained from the Integrated Risk Information System (IRIS, 1993) or

other lexicological data in the literature. Total exposure of the wildlife species of

concern (while-tailed deer) to ECOPCs in surficial soils will be determined by estimating

the chronic daily intake (CDI) dose. This CDI will be compared to the TRV lo

determine if the ECOPC concentrations are protective of species viability for the wildlife

species of concern.


2.0 Exposure Assessment

The exposure assessment is conducted to estimate the magnitude of actual or

potential exposure of specific receptors to contaminants associated with the site along

with the related uncertainties involved with the assessment. Development of the exposure

routes is discussed in Section 1.5 of this BERA. A graphical representation of the

ecological conceptual model, illustrating the exposure routes assessed in this BERA, is

presented in Figure 1-2.

2.1 Ecological Chemicals of Potential Concern The sediments and surface soils of the South Pond, Forested Wetland, and the

Drainage Ditch were sampled and analyzed for a wide range of chemicals. However,

the most potentially significant chemicals, in terms of ecoloxicology, were determined

to be aldrin and dieldrin. While other contaminants were present in the area evaluated,

these were not significant toxicants when compared lo aldrin and dieldrin.

2.2 Exposure Point Concentrations The exposure point concentration is the concentration of a chemical in an

environmental media to which a specific receptor is exposed. It is generally calculated

using statistical methodology from a set of data derived from environmental sampling.

There were relatively few samples obtained in locations necessary to fully evaluate the

exposure point concentrations. Therefore, for the purposes of this BERA, the average

of the concentrations obtained in each of the three habitats of concern was used as the

exposure point concentration.

There were two sediment samples (SED-OOl and SED-002) collected by BVWS,

eleven wetland surface soil samples (SB-6, SB-9, SB-10, SB-11, SB-12, SS-3, SS-4, SS-

5, SP-F, SP-G, and SP-H) collected by Eckenfelder, and four drainage ditch composite

surface soils (SS/71-80, SS/81-90, SS/91-100, and SS/101-120), collected by Miles

Corp., used in this BERA. The exposure point concentrations for aldrin and dieldrin in

each habitat under evaluation are shown in Table 2-1.

2.3 Exposure and Intake Assumptions Total exposure of three terrestrial target wildlife species (beaver, white-tailed deer,

and mallard) to aldrin and dieldrin in surficial soils and sediments was determined by


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estimating the chronic daily inlake (CDI) dose. The equations used to estimate the CDI

vary slightly between species and are shown on the worksheets in Tables 2-2, 2-3, and

2-4.

The wildlife species selected included both herbivorous and insectivorous species;

however, only vegetation ingestion and incidental soil ingestion were examined in this

BERA. There is limited informalion addressing invertebrate and insect uptake and

bioaccumulation of contaminants; therefore, an accurate determination of the contaminate

dose from this portion of the diet would nol be practical.

2.3.1 Plant Uptake

Plant tissue concentrations of aldrin and dieldrin were estimated by using soil to

plant transfer coefficients (TCv), developed from the octanol/water coefflcient for each

chemical (Travis 1988; Howard, 1991). The TCv generally indicated the amount of

contaminant present in plant tissues given a known soil concentration. The values for

TCv are shown on the worksheets in Tables 2-2, 2-3, and 2-4.

2.3.2 Beaver Exposure The beaver feeding rate was estimated from a general feeding rate value for

herbivorous mammals to be 772.72 grams/day (USEPA, 1993). The beaver is a strict

herbivore, obtaining 100 percent of its diet from plant sources (USFWS, 1983). The

body weight of the beaver is estimated to be approximately 20.0 kg (Burt, 1976). The

home range of the beaver is approximately 0.17 hectares (USFWS, 1983). The beaver

is estimated to incidentally ingest soil at a rate of approximately 2.4 percent of its overall

ingestion rate or 18.55 grams/day (USEPA, 1983).

2.3.3 White-Tailed Deer Exposure The white-tailed deer feeding rate is 1,600 grams/day (Dee, 1991). The white-tailed

deer is a strict herbivore, obtaining 100 percent of its diet from plant sources (Burt,

1976). The body weight of the deer is estimated to be approximately 45.40 kg (Burt,

1976). The home range of the deer is approximately 183.70 hectares (Dee, 1991). The

deer is estimated to incidentally ingest soil at a rate of approximately 1.0 percent of its

overall ingestion rate or 16.0 grams/day (USEPA, 1993).


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2.3.4 Mallard Exposure The mallard feeding rate was estimated to be approximately 337.5 grams/day

(USEPA, 1993). The mallard is omnivorous, obtaining approximately 30 percent of its

diel from plant sources and the remaining 70 percent from insects and benthic

invertebrates (USEPA, 1993). The body weight of the mallard is estimated lo be

approximately 1.03 kg (USEPA, 1993). The home range of ihe mallard is approximately

540.0 hectares (USEPA, 1993). The mallard is estimated to incidentally ingest soil at a

rale of approximately 2.0 percent of its overall ingestion rate or 6.75 grams/day

(USEPA, 1993).

2.3.5 Benthic Community Exposure The NOAA ER-L criteria will be used as a benchmark to establish adverse effects to

the benihic community for South Pond sediment aldrin and dieldrin concentrations.

Actual exposure surrogate organisms in the South Pond will nol be determined for this

evaluation since the screening values used to develop QIs are based on field toxicity

studies, and there is little speciflc informalion available in the scientific database.


3.0 Ecological Effects Assessment

3.1 Toxicity Characterization In this ecological effects assessment, information on the toxicity of aldrin and

dieldrin lo ecological receptors is presented. The toxicity informalion is used in the

development of lexicological reference values (TRVs) (i.e., acceptable daily doses or

media concentrations) for selected target species. A comprehensive literature and

database search was performed to identify relevant toxicological data for the target

receptors. The data sources that were reviewed included:

Chemical Abstracts (CA Service)

Integrated Risk Information System (IRIS)

Health Effects Assessment Summary Tables (HEAST)

Hazardous Substances Data Base (HSDB)

Phytotox

In addition to these databases, toxicity information was obtained from a variety of

primary literature sources as presented throughout the following subsections.

3.2 Toxicological Safety Factors Species-specific toxicity data for target wildlife species often were not available for

the chemicals of potential concern. Thus, where possible, toxicity values from the

literature were selected using Ihe most closely related species. Data for chronic toxicity

were preferentially used, when available. Toxicity values selected for the assessment

were the lowest exposure doses reported to be toxic or the highest doses associated with

no adverse effect.

Since toxicity data for terrestrial wildlife are not nearly as complete as that found for

laboratory and aquatic species, extrapolation of toxicity data from other animal studies

is often necessary. Because of the uncertainty associated with these extrapolations, safety

factors are applied to toxicological data to derive TRVs.

For those chemicals for which only acute lethality values were available, toxicity

values for this assessment were derived by dividing the acute toxicity value by the

appropriate safety factors. Based upon the guidance provided by the USEPA (1986c),

a median lethal dose (LD50) may be extrapolated to an acute toxicity threshold by


dividing the LD50 by a safety factor of 5. This safely factor is based on an analysis of

dose-response data for pesticides. A dose-response five times lower than the LD50 would

be expected lo result in a mortality rate of about 0.1 percent under typical conditions,

and up to 10 percent when the responses in the test population are highly variable.

Protection of 90 lo 99 percent of a population is expected lo provide an adequate margin

of safety. In the absence of similar information from chronic studies, a safely factor of

5 was also applied in the extrapolation of a chronic lowest-observable-adverse-effect-level

(LOAEL) to a chronic no-observable-adverse- effect-level (NOAEL). This type of

approach has been routinely used in aquatic toxicology, and was also adopted for use in

this assessment.

There is currently no USEPA guidance available for the extrapolation of acute

toxicity data to chronic NOAELs. However, several studies have evaluated the

relationship between LDso values and chronic NOAELs for the same chemical in small

mammals (Venmen and Flaga, 1985; Layton et al., 1987) and have found that the ratio

of LD50 to a chronic NOAEL (LD50/NOAEL) typically ranges from 10 to 1000. For the

purpose of this ecological assessment, a safety factor of 500 (5 for LD50 — > acute

toxicity threshold, and 100 for acute toxicity threshold — > chronic NOAEL) was used

to extrapolate from an LD50 concentration to a chronic NOAEL. An additional safety

factor of 5 was applied in these cases when the test species differed from the target

species selected for the site, since animal species can exhibit differences in sensitivity to

a chemical.

3.3 Ecological Effects Characterization The potential ecological effects to the benthic macroinvertebrate community of South

Pond was evaluated by comparing known contaminant concentrations in sediment to

EPA, State, or other appropriate regulatory screening values. The potential ecological

effects to the three terrestrial target species was evaluated by comparing the known

contaminant concentrations to existing scientific literature and by comparing the exposure

doses to TRVs. These TRVs and screening values are the measurement endpoints used

in this BERA and are summarized in Table 3-1.

Des Moines TCE Site • 0U4 Ecological Risk Assessment November 2 1 , 1994 * 15

•

•

3.3.1 Beaver Chemical-specific toxicity data for the beaver was not found in the literature.

Alternatively, beaver TRVs for aldrin and dieldrin were extrapolated from the LOAEL

values for laboratory rats, 0.025 and 0.005 mg/kg-day, respectively. The rat and the

beaver are both members of the order Rodentia, although they are members of different

families within the order. Additionally, the diet and digestive tract of these two species

is somewhat different. Because of the uncertainty involved in extrapolating between

species, a safety factor of 5 was applied to the rat LOAELs to develop NOAELs and a

safety factor of 5 was applied to these NOAELs to derive TRVs for the beaver. The

TRV for aldrin in the beaver was estimated to be 0.001 mg/kg-day. The TRV for

dieldrin in the beaver was estimated to be 0.0002 mg/kg-day.

LOAEL„. ^ 5 - > NOAEL„. ^ 5 - > TRV^,„

3.3.2 White-Tailed Deer Chemical-specific toxicity data for aldrin in the white-tailed deer was not found in

the literature. Alternatively, a TRV for aldrin was extrapolated from the LOAEL values

for laboratory rats, 0.025 and 0.005 mg/kg-day, respectively. The rat and the white-

tailed deer are both members of the phylogenic class Mammalia although they are

members of different orders within this class. Additionally, the diet and digestive tract

of these two species is somewhat different. Because of the uncertainty involved in

extrapolating between species, a safety factor of 5 was applied to the rat LOAEL for

aldrin to develop a NOAEL and a safety factor of 5 was applied to this NOAELs to

derive a TRV for the white-tailed deer. The TRV for aldrin in the deer was estimated

to be 0.001 mg/kg-day.

LOAEL„, ^ 5 " > NOAEL„, ^ 5 - > TRV,„,

Chemical-specific toxicity data for dieldrin in the white-tailed deer was not found in

the literature; however, there was specific toxicity data for the mule deer, a member of

the same genus as the white-tailed deer. The TRV for dieldrin was extrapolated from

the minimum LD50 for the mule deer, 100 mg/kg. The safety factor for converting the

LD50 to a chronic NOAEL was 500. The TRV for dieldrin in the deer was estimated to

be 0.2 mg/kg-day.

LD5o^500"> TRV,,„


•

•

3.3.3 Mallard

Chemical-specific toxicity data for aldrin and dieldrin in the mallard was found in

the literature. The TRV for aldrin and dieldrin in young mallards was extrapolated from

the LD50, 520 and 381 mg/kg. The safety factor for converting the LD50 to a chronic

NOAEL was 500. The TRV for aldrin in the mallard was estimated to be 1.04 mg/kg-

day. The TRV for dieldrin in the mallard was estimated to be 0.76 mg/kg-day.

L D 5 o - 5 0 0 - > TRV„.„„,

3.3.4 Benthic Macroinvertebrate Community The toxicity of dieldrin to benthic macroinvertebrates was assessed by comparing

sediment concentrations in South Pond to the National Oceanic and Atmospheric

Administration (NOAA) lowest observed effects-range (ER-L) toxicological data for

benihic macroinvertebrates in aquatic sediments. The NOAA ER-L for dieldrin in

aquatic sediments is 0.02 parts per billion (ppb) (USEPA, 1991).

There was no NOAA or other toxicological data located for aldrin to benthic

macroinvertebrates. Since aldrin is chemically related to dieldrin, the dieldrin NOAA

ER-L was used for aldrin for the purposes of this BERA.


•

4.0 Risk Characterization

The risk characterization portion of the BERA estimates baseline risks lo specific

receptors or individuals representative of a trophic groups of receptors based on the

informalion gathered during the exposure and toxicity assessments. In instances where

ARAR's have been developed for specific chemicals of concern, a comparison of

ARAR's and risk based remediation goals will be made. Also included in the risk

characterization section, will be a evaluation of the uncertainty associated with the

calculations and assumptions made throughout the BERA.

Risk characterization is the final phase of a risk assessment. It is at this phase that

the likelihood of adverse effects occurring as a result of exposure to a stressor are

evaluated.

Quotient indices (QIs) were calculated in sediment for benthic macroinvertebrates

and in surface soil for terrestrial receptors. A quotient index of less than 1 is not

considered to be indicative of risk. Quotient indices exceeding 1, but less than 10

indicate a small risk of ecological effects. Quotient indices exceeding 10 indicate a

significant risk of ecological effects. Quotient indices exceeding 100 indicate a critically

significant risk of ecological effects.

It is important to note that the actual or estimated NOAEL values used in

establishing risk in this BERA are representative of chronic effects. As such, the HQ

generated for the contaminants at the site may not be indicative of current conditions,

rather, those that may occur over time. As the HQ increases, the risk of long-term,

chronic effects on the receptors of concern would increase.

4.1 Risks to Aquatic Wildlife

4.1.1 Beaver Potential risk to the beaver inhabiting the South Pond and adjacent wetland area was

estimated by comparing the estimated daily dose of aldrin and dieldrin (in wetland soils)

with the TRVs derived for the beaver. As shown in Table 4-1, the quotient indices for

aldrin and dieldrin in the beaver exceed unity, approximately 2.6 for aldrin and 20.4 for

dieldrin. These QIs would suggest a small to significant risk of long-term chronic

reproductive effects to the beaver and other aquatic mammals that may be present at the

site.


4.1.2 Mallard Potential risk to the mallard, which may inhabit South Pond was estimated by

comparing the estimated daily dose of aldrin and dieldrin (in South Pond sediment) with

the TRVs derived for the mallard. As shown in Table 4-1, the quotient indices for aldrin

and dieldrin in the mallard are both below unity. These QIs would suggest little potential

risk lo the mallard or waterfowl from aldrin and dieldrin in the South Pond sediments.

4.1.3 Benthic Macroinvertebrate Community Potential risk to the benthic macroinvertebrate community of South Pond was

estimated by comparing the average concentrations of sediment in South Pond lo the

NOAA ER-L screening values to determine if they are exceeded. The ratios of the

maximum detected concentration to the NOAA ER-L screening values were calculated

for aldrin and dieldrin, resulting in a Ql. As shown in Table 4-2, the quotient indices

for aldrin and dieldrin in the South Pond sediments are 220,000 and 9,250, respectively.

These QIs would suggest a critically significant risk to the benihic habitat from both

aldrin and dieldrin in pond sediment.

Comparing ihe sediment concentrations of aldrin and dieldrin in the South Pond to

the NOAA ER-M screening value results in QIs of 550 and 23, respectively. The ER-M

screening value represents the median concentration that caused effects to tested benthic

organisms.

The effects of aldrin and dieldrin at the detected concentrations in the South Pond

may have serious impacts to aquatic habitat viability. These concentrations may result

in the decrease in viability of the benthic community in the South Pond, which, in turn,

would result in loss of food sources for waterfowl, fish, and other wildlife.

4.2 Risks to Terrestrial Wildlife 4.2.1 White-Tailed Deer

Potential risk to the white-tailed deer inhabiting the uplands and wetlands adjacent

to the South Pond was estimated by comparing the estimated daily dose of aldrin and

dieldrin (in wetland soils and drainage ditch soils) with the TRVs derived for the deer.

As shown in Table 4-1, the quotient indices for aldrin and dieldrin in the deer are below

unity. These QIs would suggest little risk to the deer from aldrin and dieldrin.

4.3 Uncertainty


•

There are a number of points in the decision making process of an ecological risk

assessment where there are inherent uncertainties. As a result, it is often necessary to

make certain assumptions to facilitate the preparation of the risk assessment. When data

is lacking, conservative assumptions are made to be protective of the environment.

4.3.1 Endpoint Comparison Uncertainty

There is uncertainty in the ecological endpoint comparison. The values used in the

ecological endpoint comparison (the NOAA ER-L screening values, and the TRVs) are

set to be protective of a majority of the potential receptors. The majority of wildlife

species, populations and communities are not evaluated directly as part of this BERA.

There will be some species that will not be protected by the values because of their

increased sensitivity to the chemicals. Additionally, the toxicity of chemical mixtures

is not well understood. The toxicity information used in the ecological risk assessment

for evaluating risk to ecological receptors is for individual chemicals. Chemical mixtures

can affect the receptors very differently than the individual chemicals.

4.3.2 Exposure Assessment Uncertainty In the Exposure Assessment, a number of conservative assumptions were made. The

most significant of these conservative assumptions concerns the use of the CDI models

to evaluate decreased viability to terrestrial receptors. The most critical of the factors

used in this exposure calculations include: (1) the estimation of the soil-to-plant transfer

coefficients (TCv) of contaminants; and (2) the use of average concentrations in soil at

the exposure point concentrations.

The TCv is an estimate of the relationship between soil concentrations and root

uptake and may not adequately estimate the contaminant concentrations in the edible

portion of the plant.

The use of an average concentration in the media evaluated may over estimate the

actual area of contamination and does not permit the location of risk-based "hot spots"

of contamination. Additionally, the exposure point concentrations are based on a very

low number of overall samples, which may not indicate condidons over the entire area

of concem. It is possible that average values may overestimate or underestimate the

ecological risks at the site from the evaluated media.

Other key exposure uncertainties are inherent in the CDI models developed since

they do not account for invertebrate ingestion, dermal adsorption, and inhalation. These

may be important contributors of contaminant exposure and have not been evaluated in

Des Moines TCE Site - 0U4 Ecological Risk Assessment November 2 1 , 1994 2 0

•

•

this BERA. As a result, the risk assessment section may underestimate ecological risks.

4.3.3 Ecological Effects Assessment Uncertainty

The NOAA screening values were developed using data from freshwater, estuarine,

and marine environments. Therefore, their applicability for use to evaluate potential

effects to aquatic receptors from aldrin and dieldrin in freshwater habitats must be

evaluated on a chemical-specific basis because of differences in both the toxicity of the

individual chemicals lo freshwater and saltwater organisms, and the bioavailability of

contaminants in the two aquatic systems. Additionally, the lack of a NOAA ER-L

screening value for aldrin resulted in the use of the dieldrin ER-L. The toxicity and

lexicological effects of aldrin is likely to be different from dieldrin, even though they are

similar chemicals.

The development of TRVs is an es.senlial component of the ecological risk

assessment since these become the benchmark for risk determination. The use of a

laboratory rat LOAEL te develop beaver and deer TRVs dees net adequately address

differences in the habits, anatomy, and physiology of these species. Additionally, the

habitat conditions are vastly different between that of a laboratory animal and that of the

wild deer and beaver. There is a larger uncertainty in the use of LDJQS to develop deer

and mallard TRVs since it is difficult to extrapolate these to an acute toxicity threshold.

An attempt to compensate for this uncertainty is made by the use of safety factors

to convert LDJQS, LOAELS, and NOAELs to TRVs specific to each wildlife species.

One of the safety factors which is applied is recommended by the USEPA (1986c) for

use in extrapolating LD50S to an acute toxicity threshold. The remaining safety factors

have been developed after reviewing species-sjjecific acute and chronic toxicity data or

are based on best professional judgment.

4.4.4 Ecological Risk Assessment Unceirtainty The uncertainties present in the exposure assessment and ecological effects

assessment are compounded in the risk assessment, which compares the findings of the

exposure assessment to toxicity values developed in the ecological effects assessment.

There was one chemical detected in the South Pond sediments (aldrin) that did not have

a NOAA ER-L screening value. Therefore, there was uncertainty in the development

of the Ql for the aquatic receptors being evaluated.

Des Moines TCE Site - 0U4 Ecological Risk Assessment • November 21, 1994 21

•

•

5.0 Conclusions and Ecological Significance

The findings of the BERA will be summarized in this section. The summary will

discuss the relevance of the measurement endpoints to the developed assessment

endpoints.

5.1 Aquatic Receptor Measurement Endpoints The measurement endpoint used to assess the aquatic habitat is decreased viability

of the benthic macroinvertebrate community. The habitat evaluation indicated that there

is an aquatic habitat, the South Pond, present at the site.

There is significant potential for decreased viability of the benthic community as a

result of the high concentrations of aldrin and dieldrin detected in the pond sediments,

which exceeded the NOAA ER-L and ER-M measurement endpoints. Aldrin, which

accounts for most of the Ql to receptors in this habitat, is not only potentially toxic to

benthic organisms through a direct exposure pathway, but as indicated by its high BCF

value, has a high potential to bioconcentrate in aquatic organisms. Therefore, ether

organisms that feed upon these organisms will be exposed to pesticides by this indirect

exposure pathway.

There is a small to significant potential for long-term chronic reproductive effects

to beaver and other small mammals that utilize the forested wetland habitat surroundng

South Pond. Estimated doses of aldrin and dieldrin exceeded the chronic toxicologial

effects levels of both chemicals te rodents.

Suggested remedial goals for aldrin and dieldrin concentrations, in the South Pond

sediments, that would be protective of the benthic community would range from 0.2 ppb

to 8 ppb for both chemicals, based on the NOAA ER-L and ER-M benthic toxicology

data used as the screening benchmark (EPA, 1993).

Suggested remedial goals for aldrin and dieldrin concentrations, in wetland soils

surrounding South Pond, that would result in a small risk to the beaver population (and

other small mammals) would range from 0.285 to 1.48 (status quo) for aldrin and 0.32

to 3.08 ppm for dieldrin. These estimated remedial goals are based on reducing

cumulative risk from the two chemicals to the QI = 1 lo 10 range. Reducing chemcials

concentrations to the above stated ranges will result in cumulative QIs of less than 1 te

less than 10.


•

5.2 Terrestrial Receptor Measurement Endpoints The measurement endpoint used te assess the terrestrial environment is decreased

viability of terrestrial wildlife species. The habitat evaluation indicated that there are

significant populations of deer on the site. Additionally, beaver is known to be present

at the shoreline of the South Pond and habitat is present for waterfowl. There was little

apparent risk to the three terrestrial endpoints evaluated at the site from aldrin and

dieldrin concentrations in wetland soils and the drainage ditch. These chemical

concentrations, when evaluated te determine the daily dose for each receptor, were below

the chemical-specific TRVs.

5.3 General Conclusions In general, the QIs for the benthic macroinvertebrate community of the South Pond

are very high, based on the concentrations of aldrin and dieldrin detected in the South

Pond sediment samples. There appears te be little risk posed by the chemical

concentrations in the wetlands surface soils and drainage ditch surface soils.

The ecological effects assessment indicates that the concentrations of aldrin and

dieldrin present in the South Pond sediment may cause an increase in mortality to benthic

species and decrease abundance and diversity of benthic species.

5.4 Recommendations The conclusions of this BERA seem to suggest that there may be significant

ecological risks associated with portions of this site. These risks are significant enough

that remedial activities may be required to be protective of the environment; however,

remedial activides in the wetland and the South Pond would physically alter er eliminate

the habitat it is intended to remediate.

The maintenance of the status quo will continue to allow aldrin and dieldrin, which

are both bioaccumulative, to persist in the food chain. Therefore, available remedial

options should reduce or eliminate the exposure threat to contaminated sediment. Some

options may include dewalering of the pond and removal of the contaminated sediments.

This option would allow the pond to become reestablished with a benthic community and

possibly enhance the surrounding habitat. Another option may involve the dewalering

of the pond and covering of the sediments with clean fill. This would also allow

reeslablishmenl of the pond habitat. Other potential options may include the filling of

the South Pond, thus eliminating the exposure risk and the habitat. This alternative


•

would probably have a negative effect on the surrounding wetlands, which are partially

dependant en the surface water provided by the pond.

• Des Moines TCE Site - 0U4 Ecological Risk Assessment November 21 , 1994 2 4

•

6.0 References

BVWS (BLACK & VEATCH Waste Science, Inc.), March 1994. Data Report for South

Pond Sediment Samples SED-001 and SED-002.

BVWS (BLACK & VEATCH Waste Science, Inc.), March 1994. Des Moines TCE

0U4 Draft Habitat Evaluation Report - South Pond Study Area.

Bull and Farrand, 1977. The Audobon Society Field Guide to North American Birds -

Eastern Region, Alfred Knopf, New York, NY.

Burl, 1996. A field Guide to the Mammals of America North of Mexico, Houghton-

Mifflin Company, Boston, MA.

Dee, J.C. November 1991. "Methodology for Assessing Potential Risks To Deer

Populations: A Case Study al a Superfund Site." Paper presented at the 1991 Annual

Meeting of the Society of Environmental Toxicology and Chemistry. Abstract No. 426.

HEAST, March 1993. Health Effects Assessment Summary Tables. Office of Research

and Development. Office ef Emergency and Remedial Response. U.S. Environmental

Protection Agency.

Howard, 1991. Handbook of Environmental Fate and Exposure Data for Organic

Chemicals. Volume III - Pesticides, Lewis Publishers, Celsea, MI.

IRIS. August 1993. Integrated Risk Information System. Accessed through Chemical

Information Systems, Inc., Baltimore, MD.

Layton, D.W., B.J. Mullon, D.H. Rosenblatt, and M.J. Small, 1987. "Derivin

Allowable Daily Intakes for Systemic Toxicants Lacking Chronic Toxicity Data".

Regulatory Toxicology and Pharmacology, 7:96-112.

Miles Corporation, July 1994. Data Report of Surficial Soil Samples from Wetland Soils

and the Drainage Ditch at the Des Moines TCE Site - 0U4.


•

Travis, Curtis C. and Angela Arms, 1988. "Bioconcentration of organics in Beef, Milk,

and Vegetation". Environmental Science Technology. Vol 22, No. 3

USEPA (U.S. Environmental Protection Agency), December 1993. Wildlife Exposure

Factors Handbook, Volumes I and II, Office of Health and Environmental Assessment,

Washington, DC.

USEPA (U.S. Environmental Protection Agency), February 1992. Peer Review

Workshop Report on a Framework for Ecological Risk Assessment, Risk Assessment

Forum, Washington, DC.EPA/625/3-91/022.

USEPA (U.S. Environmental Protection Agency), July 1994. Region III Interim

Ecological Risk Assessment Guidelines, Technical Support Section, Superfund Program

Branch, Philadelphia, PA.

USEPA (U.S. Environmental Protection Agency), April 1991. Suggested Guidance for

Evaluating Sediment Concentration Data, Region IV Contaminated Sediments

Workgroup, Atlanta, GA.

USEPA (U.S. Environmental Protection Agency), 1986c. Ecological Risk Assessment,

Office of Pesticide Programs, Washington DC. EPA/540/9-85/001.

USFWS (U.S. Fish and Wildlife Service), April 1983. Habitat Suitability Index Models:

Beaver, Department of the Interior, Washington DC.

Venman, B.C., and C. Flaga, 1985. "Development of an Acceptable Factor to Estimate

Chronic Endpoints from Acute Toxicity Data". Toxicol. Ind. Health. 1:261-269.


j « v

% V

South Pond Sedi mentis

Forested Wetland Soils

Legend:

Direct Ingestion

- Incidental Ingestion

Figure 1 -2 Conceptual Ecological Model Des Moines TCE - 0U4 Site

Des Moines, lowa

Table 2-1

Aldrin and Dieldrin Concentrations at

Des Moines TCE-0U4 Ecological Risk Assessment

Des Moines, lowa

Chemical Frequency of Delects Minimum Detected Concentration

Maximum Detected Concentration

Average Concentration 1

1 - •• • • Wetland Surface Soils

Pesticides/PCBs (ppm) Aldrin Dieldrin

8/11 8/11

0.002 0.015

9.4 59.0

1.48 8.65

Discharge Ditch Composite Surface Soils 1

Peslicides/PCBs (vvb) Aldrin

1 Dieldrin 3/4 4/4

8.7 640.0

53.0 7,000.0

15.4 3,085.5

South Pond Sediments

Pesticides/PCBs roob^ Aldrin Dieldrin

2/2 2/2

1,500.0 180.0

7,300.0 190.0

4,400.0 185

Notes: 1. Sediment samples used for this evaluation included SED-001, SED-002 (BVWS, 1994). 2. Surface soil samples used for this evaluation included 6, 9, 10, 11, 12, SS-3, SS-4, SS-5, SP-1-, SP-G, SP-H, SS/71-80, SS/81-90, SS-91-100, SS/101-120 (Eckenfelder, 1993; Miles, 1994).


^^^^^B

5 ^ § SS d ^ ^

^

Table 2-2 Ingestion Dose Worksheet for the Beaver

Des Moines TCE-0U4 Site Des Moines, lowa

Exposure Equation:

[(TCv * IR) + SIR] * CSw * FI BW * CF

Species Specific Information: Factor Area of Contamination, hectares Home Range, hectares Fraction of Diet from AOC (AOC/HR) Body Weight, Kg Ingestion Rate, g/day (BVV^O.yZ? * 0.577) Soil Ingestion Rate, g/day (BW * 2.4%) Conversion Factor, g/kg Contaminant Concentration in Wetland Soil, mg/kg Soil to Plant Transfer Coefficient, unitless Contaminant Dose, mg/kg-day

Abbreviation AOC HR Fl BW IR SIR CF CSw TCv Dose

Unit Reference 0.30 0.17 1.00 20.00 772.72 18.55 1000.00 varies varies See below

•

Contaminant Specific Information: Contaminant Aldrin Dieldrin

CSw 1.48 8.65

ICv 0.021 0.098

Dose 2.57E-03 4.08E-02

Table 2-3 Ingestion Dose Worksheet for the Deer


Exposure Equation:

{(CSw * Flw) + (CSd * Fid) + [SIR * (Flw + Fid)]} BW*CF

TCv *IR

Species Specific Information: Factor Abbreviation Unit Wetland Soil Area of Contamination, hectares AOCw 1.00 Ditch Soil Area of Contamination, hectares AOCd 1.00 Home Range, hectares HR 183.70 Fraction of Diet from Wetland Soil (AOCw/HR) Flw 0.0054 Fraction of Diet from Ditch Soil (AOCd/HR) Fid 0.0054 Body Weight, Kg BW 45.40 Ingestion Rate, g/day IR 1600.00 Soil Ingestion Rate, g/day (BW * 1.0%) SIR 16.00 Conversion Factor, g/kg CF 1000.00 Contaminant Concentration in Wetland Soil, mg/kg CSw varies Contaminant Concentration in Ditch Soil, mg/kg CSd varies Soil to Plant Transfer Coefficient, unitless TCv varies Contaminant Dose, mg/kg-day Dose See below

Reference


CSy 1.48 8.65

CSd 0.015 3.085

TCv 0.021 0.098

Dose 6.02E-06 2.21 E-04

Table 2-4 Ingestion Dose Worksheet for the Mallard


Exposure Equation:

[(TCv * VIR) + SIR] * CSw * FI BW*CF

Species Specific Information: Factor Area of Contamination, hectares Home Range, hectares Fraction of Diet from AOC (AOC/HR) Body Weight, Kg Ingestion Rate, g/day Percentage of Vegetation in Diet Vegetation Ingestion Rate, g/day (IR * PV) Soil Ingestion Rate, g/day (BW * 2.0%) Conversion Factor, g/kg Contaminant Concentration in Pond Sediment, mg/kg CSp Soil to Plant Transfer Coefficient, unitless Contaminant Dose, mg/kg-day

Abbreviation AOC HR Fi BW IR PV VIR SIR CF CSp TCv Dose

Unit Reference 0.40 540.00 0.0007 1.03 337.50 30.0% 101.25 6.75 1000.00 varies varies See below

•

Contaminant Specific Information: Contaminant Aidrin Dieldrin

CSp 4.40 0.19

ICy 0.021 0.098

Dose. 2.84E-05 2.24E-06

Table 3-1

Measurement Endpoints for Aquatic and Terrestrial Receptors

Des Moines TCE-0U4 Ecological Assessment

Des Moines, lowa

Chemical

Pesticides

Aldrin

Dieidrin

Aquatic

Endpoint

NOAA

ER-L

Values

NA (0.02)

0.02

Terrestrial Endpoints

Beaver

TRV

(mg/kg-day)

0.001

0.0002

Deer

TRV

(mg/kg-day)

0.001

0.2

Mallard

TRV

(mg/kg-day)

1.04

0.76

Note:

1. NA - NOAA Screening Value is not available

Des Moines TCE Site - OU4 Ecological Risk Assessment November 2 1 , 1994

•

Table 4-1

Quotient Indices for Wildlife Species

Des Moines TCE-0U4 Site

Des Moines, lowa

Species

Beaver

Deer

Mallard

Contaminant

Aldrin

Dieldrin

Aldrin

Dieldrin

Aldrin

Dieldrin

Dose

mg/kg/day

0.00257

0.0408

0.00000602

0.000211

0.0000284

0.0000224

TRV

0.001

0.002

0.001

0.2

1.04

0.76

Effects

LOAEL„, modified to NOAEL b..v„

LOAEL„, modified to NOAEL b,.,„

LOAEL„, modified to NOAEL ^„

LD50^„ modified to NOAELj,„

LD50^,„j modified to NOAEL^,.,^

LD50^,„j modified to NOAEL^,„,

Quotient

Index (Ql)

2.57

20.4

0.006

0.001

0.0000273

0.0000295

ZQI

22.97

0.007

0.0000568


•

Table 4-2

Quotient Indices for the Benthic Macroinvertebrate Community of South Pond


Des Moines, lowa

Spedes

Eknthic Macroinvertebrates

Contaminant

Aldrin

Dieldrin

Sediment

Concentration

(ppb)

4,400

185

NOAA

ER-L

0.02

(NA)

0.02

Effects

Increased benthic mortality,

decreased benthic abundance


decreased benthic abundance

Quotient ludex

(Ql)

220,000.00

9,250.00

SQl

229,250.00

Des Moines TCE Site - OU4 Ecological Risk Assessment November 2 1 , 1994

•

UNITED STATES ENVIRONMENTAL PROTECTION AGE OFFICE OF RESEARCH AND DEVELOPMENT

ENVIRONMENTAL CRITERIA AND ASSESSMENT OFFICE CINCINNATI , OHIO 4 5 2 6 8

MEMORANDUM

DATE:

SUBJECT:

FROM:

TO:

DEC 1 2 VAH

SPFD fitJAl^Cb RZCIO)? V I I

December 2, 1994

Review of the Draft Ecological Risk Assessment performed on the Des Moines TCE-0U4 site (Des Moines TCE-0U4/Des Moines IA)

W^Joan S. Dollarhide.-/c:'i(.'^ (-'-'•( i ^ Director / I'

Superfund Health Risk Technical Support Center

Glenn Curtis U.S. EPA Region Vll

This memorandum responds to your request for a review of the Draft Ecological Risk Assessment performed on the Des Moines TCE-0U4 site. Please see attached review conducted by Dave Reisman(ECAO) and Chris Cubbison(ECAO). Please contact the Superfund Health Risk Technical Support Center at (513) 569-7300 with any additional questions.

\ ^ Printed on Recycled Paper

•

Attachment

The following is a summary of comments on the Ecological Risk Assessment for Operating Unit 4 of the Des Moines TCE site. The ECAO scientists who reviewed this assessment were Dave Reisman and Chris Cubbison.

This ecological risk assessment is incomplete in a number of ways and cannot be considered to be an ecological risk assessment. At best, it is a wildlife toxicity assessment. An ecological risk assessment should include discussions on population dynamics for one or more species at each trophic level from primary producers (plants) to tertiary (and higher) consumers. It would not be surprising if the ponds were not visited by raccoons feeding on fish and benthic invertebrates. Raccoons could be at greater risk than beavers (reported on in the study) because of the effect of bioconcentration in the food web.

While ecological risk assessments are fairly new, there are some basic ecological principles and draft documentation that could have been used to develop this document. In general, it would have been helpful if the authors had cited sources if standard methods were employed. The following are specific comments:

The report makes use of some new terminology and proposes new safety/uncertainty factors with little or no scientific supporting data and no justification. The Great Lakes Initiative (GLI) terminology (U.S. EPA, 1993) could temporarily fill this need until other Agency guidance is developed. Additional sources such as Glenn Suter's book on Ecological Risk Assessment provides information on some different calculations that can be used to base the risk assessment. EPA/Risk Assessment Forum case studies could also be used to formulate the structure.

It would have been helpful if there was more general background provided. How was the site being used in previous years? How did these levels of aldrin and dieldrin get into wetlands and other areas where you would not expect them? Were these caused from the flood of 1993 or was it due to poor disposal practices?

The discussion of rare or endangered species (Section 1.4.5) fails to discuss whether any were looked for. The question is: Is this habitat used by species that should be there but aren't? In other words, in similar areas, are there endangered species?

Section 1.5.1 states that no plant tissues were sampled for chemical contamination. Since the keystone species discussed in this report were all herbivores, failure to sample plants is a major omission. Estimating plant levels based upon the octanol/water partition coef. is acceptable only where you have

For internal use only. DRAFT - Do not cite or quote. -1-

•

•

supporting studies which prove its validity for each chemical or if there is some major impediment to sampling (such as a lack of standard test method).

To omit contaminated water means to omit two exposure pathways entirely-oral ingestion and dermal exposure. The report must resolve whether it can ignore these pathways because exposure or dose would be minimal. Detailed analysis of the pond was not in the report, yet the conclusion is that the most affected populations are the benthic community of that water body and those that feed on it. Furthermore, aldrin and dieldrin bioconcentrate, so aquatic life (not observed because the pond was frozen) will definitely be affected and as well as all the fish-eating animals. The report already shows the omnivorous mallard being affected by the contaminated benthic community.

There is no apparent discussion of the fate and transport of aldrin and dieldrin. These chemicals are known to undergo bioconcentration in aquatic food chains. There is no evidence that bioconcentration was considered in deriving the hazard evaluation. No fish appear to have been sampled and water concentrations of aldrin and dieldrin are lacking. Is there a risk to piscivorous wildlife (fish-eaters) such as raccoons or kingfishers?

There were no data on the decomposition products (photolysis, hydrolysis, etc.) of the chlorinated pesticides. The report only highlights these two chemicals. What is further difficult to assess is any teratogenic, mutagenic or reproductive effects from these and other chemicals present in the site. This is especially necessary given the bird population and the potential for effects.

The application of uncertainty factors (safety factors in the text) is a reasonable response to issues such as interspecies extrapolation. However, if standard methods are not used, justification should be given for the safety factor selection.

Extrapolation from an LD50 to a NOAEL using a ratio of 500 is unacceptable without a more substantive rationale. Our office studied such ratios and concluded that they were probably not scientifically defensible for protection of human health. Our analysis of ratios developed by Weil et al.(1969), McNamara (1976) and Layton et al. (1987) suggest a factor of 10,000 when estimating NOAELs from LDJQS. Lower ratios cited by the authors were based upon small samples of chemicals. Larger samples cover chemicals with more variability in toxicity and require higher ratios in order to be reasonably sure that the estimated NOAEL encompasses the actual NOAEL. Aldrin and dieldrin are reasonably well studied chemicals. A better estimate of NOAELs might be derived from the peer-reviewed literature.

Finally, little thought seems to have gone into the no-remediation option. Without the fate and transport analysis, it is not possible to predict whether aldrin and dieldrin will be permanently bound in the sediment of whether they are mobile enough


to threaten wildlife outside the boundaries of the ponds. As stated in the study, remediation of almost any sort will destroy the ponds, at least temporarily. A decision about whether or how to remediate cannot reasonably be based upon the report reviewed here.

References

Layton, D.W. et al. 1987. Reg.Tox.and Pharm. 7:96-112.

McNamara, B.P. 1976. Concepts in Health Evaluation of Commercial and Industrial Chemicals in New Concepts in Safety Evaluation: Advances in Modern Toxicology. Vol.1, Part 1, Hemisphere Pub., Washington.

U.S. EPA. 1993. Water Quality Guidance for the Great Lakes System and Correction; Proposed Rules. 40 CFR Parts 122 et al. Federal Register, Friday, April 16, 1993, 20802-21047.

Weil, CS. et al. 1969. Tox.Appl.Pharmacol. 14:426-431.


DEC- 2-94 FRi 15:16 ECAO-CINCINNAT!. AX NO. 5135697475

•

P.OI __

j ^ ^ ^ ! : ' %

UNITED STATES E N V I R O N M E N T A L PROTECTION AGENCY OrFlCe OF RESEARCH AND DEVELOPMENT

ENVIRONMENTAL CRITERIA AND ASSESSMENT OFFICE CINCINNATI, OHIO i:526a

MEMORANDUM

DATE:

SUBJECT:

December 2, 1994

Review of the Draft Ecological Risk Aseesement performed on the Des Moines TCE-0U4 sit© (Dee Moinea TCE-0U4/Des Moires IA)

FROM:

TO:

Wt.Joan S. Dol larh ide^| i^M •^Director / / "

Superfund Health Risk Technical Support Center

Glenn Curtia U.S. EPA Region Vll

This memorandum r Ecological Risk Assesamer, aee attached review condut Cubblson(ECAO), Please c Center at (513) 569-7300 w,

•RU r? C»f^ f / y '

>A)

\ Draft site. Please

ll Support

Printed on Recyclea Paper

DEC- 2 -94 FRi 15; 16 ECAO-CINCINNAT I FAX NO, 513569"'4T5 P. 02

•

A t tachment

The following ie a summary of commente on the Ecological Risk Assessment for Operating Unit 4 of the Dea Moines TCE site. The ECAO scientists who reviewed this assessment v/ere Dave Reisman and Chris Cubbison.

1/ This ecological risk assessment is incomplete in a number of ways and cannot be considered to be an ecological ri$k aeeessmont. At best, it la a wildlife toxicity aeeeeerrent. A.n ecological risk aaeesament should include discussions on population dynamics for o re or more species at each trophic level from primary producers

^ (plants) to tertiary (and higher) consumers. It would not be surprising if the ponds ^ - were not visited by raccoons feeding on fish and benthic invertebrates. Raccoons

could be at greater risk than beavers (reported on in the study) because of the effect of bioconcentration in the food web.

While ecological risk assessments are fairly new, there are some basic ecological principles and draft documentation that could have been used to develop this document. In general. It would have been helpful if the authors had cited sources if standard methods were employsd. The following are specific comments:

3 , The report makes use cf some new terminology and proposes new safety/uncertainty factors with little or no scientific supporting data and no justification. The Great Lakes Initiative (GLI) terminology (U.S. EPA, 1993) could temporarily fill this need until other Agency guidance is developed. Additional sources such ae Glenn Suter's book on Ecological Risk Assessment provides information on some different calculations thet can be used to base the risk assessment. EPA/Risk Assessment Forum case studies could also be used to formulate the structure.

<j It would have been helpful if there was more general background provided. How was the site being used in previous years? How did these levels of aldrin and dieldrin get into wetlands and other areas where you would not expect them? Were these caused from the flood of 1993 or was it due to poor disposal practices?

^ The discussion of rare or endangered species (Section 1.4.5) fails to discuss whether any were looked for, The question is: Is this habitat used by species that should be there but aren't? In other words, in similar areas, are there endangered species?

^ . Section 1.5.1 states that no plant tissues were sampled for chemical contamination. Since the keystone species discussed in this report were all herbivores, failure to sample plants is a major omission. Estimating plant levels based upon the octanol/water partition coef. ie acceptable only where you have

For internal use only. DRAFT • Do not ci te or quote. -1-

DEC- 2 -94 FRI 15 i17 ECAO-CINCINNATI FAX NO. 5135697475 P . 0 3

supporting studies which prove its validity for each chemical or if there is some major impediment tc sampling (such as a lack of standard test method).

7, To omit contaminated water means to omit two exposure pathways entirely-oral ingestion and dermal exposure. The report must resolve whether it can Ignore these pathways because exposure or dose would be minimal. Detailed analysis of the pond was not in the report, yet the conclusion is that the most affected populations are the benthio community of that water body and those that feed on It. Furthermore, aldrin and dieldrin bioconcentrate, so aquatic life (not observed because the pond was frozen) will definitely be affected and as well as all the fish-eating animals. The report already shows the omnivorous mallard being affected by the contaminated benthic community.

0 . There is no apparent discussion of the fate and transport of aldrin and dieldrin. These chemicals are known to undergo bioconcentration in aquatic food chains. There is no evidence that bioconcentration was considered in deriving the hazard evaluation. .No fish appear to have been sampled and water concentrations of aldrin and dieldrin are lacking. Is there a risk to piscivorous wildlife (fleh-eaters) such as raccoons or kingfishers?

There were no data on the decomposition products (photolysis, hydrolysis, ' etc) of the chlorinated pesticides. The report only highlights these two chemicals.

What is further difficult to assess is any teratogenic, mutagenic or reproductive effects from these and other chemicals present in the site. This is especially necessary given the bird population and the potential for effects.

jo The application of uncertainty factors (safety factors in the text) is a reasonable response to issues such as interspecies extrapolation. However, if standard methods are not used, justification should be given for th© safety factor selection.

Extrapolation from an LD55 to a NOAEL using a ratio of 500 Is unacceptable without a more substantive rationale. Our office studied such ratios and concluded that they were probably not scientifically defensible for protection of human health. Our analysis of ratios developed by Well et al.(1969). IVlcNamara (1976) and Layton et al, (1987) suggest a factor of 10,000 when estimating NOAELs from LDj^s, Lower ratios cited by the authors were based upon small sampies of chemicals. Larger samples cover chemicals with more variability in toxicity and require higher ratios in order to be reasonably sure that the estimated NOAEL encompasses the actual NOAEL. Aldrin and dieldrin are reasonably well studied chemicals. A better estimate of NOAELs might be derived from the peer-reviewed literature.

Finally, little thought seems to have gone Into the no-remedlation option. Without the fate and transport analysis, It is not possible to predict whether aldrin and dieldrin will be permanently bound in the sediment of whether they are mobile enough

•

For Internal uee only. DRAFT • Do not,cite or quote. -2- >

DEC- 2-94 FRi 15:18 ECAO-CINCINNATI FAX NO. 5135697475 P.04

to threaten v/ildiife outside the boundaries of the ponds. As stated in the study, remediation of almost any sort will destroy the ponds, at least temporarily. A decision about whether or how to remediate cannot reasonably be based upon the report reviewed here.

References

Layton, D.W. et al. 1987. Reg.Tox.and Pharm. 7:96-112.

McNamara, B.P, 1976. Concepts In Health Evaluation of Commercial and Industrial Chemicals In New Concepts in Safety Evaluation: Advances in Modern Toxicology. Vol.1, Part 1, Hemisphere Pub., Washington.

U.S. EPA. 1993. Water Quality Guidance for the Great Lakes System and Correction, Proposed Rules. 40 CFR Parts 122 et al. Federal Register, Friday, April 16, 1993, 20802-21047.

Weil, CS. etal , 1969. Tox.Appl.Pharmacol. 14:426-431.

For internal use only. DRAFT • Do not cite or quote. -3-

•

BLACK & VEATCH Waste Science, Inc. Philadelphia Office DEC 1 3 ]994

SPFD BRAIICH MEMORANDUM REGION VII

USEPA - Region VII B&V Project 71400.032 Des Moines TCE - 0U4 B&V File PHL Revisions to WTA (formerly BERA) December 9, 1994 based on EPA Cincinnati Comments

To: Glenn Curtis

From: Dane G. Pehrman

I have completed the revisions to the Wildlife Toxicity Assessment (formerly known as the Baseline Ecological Risk Assessment) based on our discussion of comments provided by EPA - Cincinnati. I have summarized our response to each comment and point out changes to the document as follows:

Comment #1 In response to this comment, we have revised the title of the document to be a

Wildlife Toxicity Assessment. This comment is specifically related to the scope of the project and since our intent was not to prepare a full-blown EA, we are comfortable with this change. In response to the second part of this comment, raccoons were excluded from this document due to a lack of data to even estimate food-chain ingestion. This is discussed in Section 1.6.1 (p. 9) and again in 4.3.1 (p. 20).

Comment #2 No response. As we discussed this comment was a general opinion.

Comment #3 Information concerning the use and references for safety factors is provided in

Section 3.3 of the document (pp. 14 and 15). Most other referenceable points are referenced in the document. The overall structure of this document is based on EPA's Risk Assessment Forum.

Comment #4 No response. This information will be part of the overall Rl.

Comment #5 No response. We have referenced the FWS memorandum in the uncertainties

section; however, no T&E species were specifically searched for. At this point, this does not seem particularly important since the response at this site is driven by the stressor, not the receptors present (or not). Tracy Copeland at FWS indicated that they

5.0 Conclusions and Ecological Significance

The findings of the WTA will be summarized in this section. The summary will

discuss the relevance of the measurement endpoints to the developed assessment

endpoints.

5.1 Aquatic Receptor Measurement Endpoints The measurement endpoint used to assess the aquatic habitat is decreased viability

of the benthic macroinvertebrate community. The habitat evaluation indicated that there

is an aquatic habitat, South Pond, present at the site.

There is significant potential for decreased viability of the benthic community as a

result of the high concentrations of aldrin and dieldrin in the pond sediments, which

exceeded the NOAA ER-L and ER-M measurement endpoints. Aldrin, which accounts

for most of the Ql to receptors in this habitat, is not only potentially toxic to benthic

organisms through a direct exposure pathway, but as indicated by its high BCF value, has

a high potential to bioconcentrate in aquatic organisms. Therefore, other organisms that

feed upon these organisms will be exposed to pesticides via this indirect exposure

pathway.

Suggested remedial goals for aldrin and dieldrin concentrations in the pond sediments

that would be protective of the benthic community would range from 0.2 ppb to 8 ppb

for both chemicals.

5.2 Terrestrial Receptor Measurement Endpoints The measurement endpoint used to assess the terrestrial environment is decreased

viability of terrestrial wildlife species. The habitat evaluation indicated that there are

significant populations of deer on the site. Additionally, beaver is known to be present

at the shoreline of South Pond and habitat is present for waterfowl.

There was little apparent risk to the three terrestrial endpoints evaluated at the site

from aldrin and dieldrin concentrations in wetland soils and the drainage ditch. These

chemical concentrations, when evaluated to determine the daily dose for each receptor,

were below the chemical-specific TRVs.

Des Moines TCE-OU4 - Ecological Risk Assessment December 9, 1994 2 2

be important contributors of contaminant exposure and have not been evaluated in this

WTA. As a result, the risk assessment section may underestimate ecological risks.

4.3.3 Ecological Effects Assessment Uncertainty The NOAA screening values were developed using data from freshwater, estuarine,

and marine environments. Therefore, their applicability for use to evaluate potential

effects to aquatic receptors from aldrin and dieldrin in freshwater habitats must be

evaluated on a chemical-specific basis because of differences in both the toxicity of the

individual chemicals to freshwater and saltwater organisms, and the bioavailability of

contaminants in the two aquatic systems. Additionally, the lack of a NOAA ER-L

screening value for aldrin resulted in the use of the dieldrin ER-L. The toxicity and

toxicological effects of aldrin is likely to be different from dieldrin, even though they are

similar chemicals.

The development of TRVs is an essential component of the wildlife toxicity

assessment since these become the benchmark for risk determination. The use of a

laboratory rat LOAEL to develop beaver and deer TRVs does not adequately address

differences in the habits, anatomy, and physiology of these species. Additionally, the

habitat conditions are vastly different between that of a laboratory animal and that of the

wild deer and beaver. There is a larger uncertainty in the use of LDJQS to develop deer

and mallard TRVs since it is difficult to extrapolate these to an acute toxicity threshold.

An attempt to compensate for this uncertainty is made by the use of safety factors

to convert LD50S, LOAELs, and NOAELs to TRVs specific to each v/ildlife species. One

of the safety factors which is applied is recommended by the USEPA (1986c) for use in

extrapolating LDJQS to an acute toxicity threshold. The remaining safety factors have been

developed after reviewing species-specific acute and chronic toxicity data or are based on

best professional judgement.

4.4.4 Wildlife Toxicity Assessment Uncertainty The uncertainties present in the exposure assessment and ecological effects

assessment are compounded in the risk assessment, which compares the findings of the

exposure assessment to toxicity values developed in the ecological effects assessment.

There was one chemical in South Pond sediments (aldrin) that did not have a NOAA ER-

L screening value. Therefore, there was uncertainty in the development of the Ql for the

aquatic receptors being evaluated.

Des Moines TCE-OU4 - Ecological Risk Assessment Decembers, 1994 21

•

4.3.1 Endpoint Comparison Uncertainty There is uncertainty in the ecological endpoint comparison. The values used in the

ecological endpoint comparison (the NOAA ER-L screening values, and the TRVs) are

set to be protective of a majority of the potenti.il receptors. The majority of wildlife

species, populations and communities are not evaluated directly as part of this WTA.

There will be some species that will not be protected by the values because of their

increased sensitivity to the chemicals. Additionally, the toxicity of chemical mixtures is

not well understood. The toxicity information used in the wildlife toxicity assessment for

evaluating risk to ecological receptors is for individual chemicals. Chemical mixtures can

affect the receptors very differently than the individual chemicals.

Other uncertainties lie in the selection of species as surrogates for trophic feeding

groups. Due to a lack of environmentsd sample data for fish and water, it was not

possible to estimate the concentration of aldrin and dieldrin in fish. Therefore, the effects

of these chemicals on piscivores was not evaluated in this WTA. As a result, actual risks

from contamination at the site may be underestimated.

4.3.2 Exposure Assessment Uncertainty In the Exposure Assessment, a number of conservative assumptions were made. The

most significant of these conservative assumptions concerns the use of the CDI models

to evaluate decreased viability to terrestrial receptors. The most critical of the factors

used in this exposure calculations include: (1) the estimation of the soil-to-plant transfer

coefficients (TCv) of contaminants and (2) The use of average concentrations in soil at

the exposure point concentrations.

The TCv is an estimate of the relationship between soil concentrations and root

uptake and may not adequately estimate the contaminant concentrations in the edible

portion of the plant.

The use of an average concentration in the media evaluated may over estimate the

actual area of contamination Jind does not permit the location of risk-based "hot spots"

of contamination. Additionally, the exposure point concentrations are based on a very

low number of overall samples, which may not indicate conditions over the entire area

of concern. It is possible that average values may overestimate or underestimate the

ecological risks at the site from the evaluated media.

Other key exposure uncertainties are inherent in the CDI models developed since they

do not account for invertebrate ingestion, dermal adsorption, and inhalation. These may


the TRVs derived for the mallard. As shown in Table 4-1, the quotient indices for aldrin

and dieldrin in the mallard are both below unity. These QIs would suggest little potential

risk to the mallard or waterfowl from aldrin and dieldrin in the South Pond sediments.

4.1.3 Benthic Macroinvertebrate Community Potential risk to the benthic macroinvertebrate community of South Pond was

estimated by comparing the average concentrations of sediment in South Pond to the

NOAA ER-L screening values to determine if they are exceeded. The ratios of the

maximum detected concentration to the NOAA ER-L screening values were calculated

for aldrin and dieldrin, resulting in a Ql. As shown in Table 4-2, the quotient indices for

aldrin and dieldrin in the South Pond sediments are 220,000 and 9,250, respectively.

These QIs would suggest a critically significant risk to the benthic habitat from both

aldrin and dieldrin in pond sediment.

Comparing the sediment concentrations of aldrin and dieldrin in the South Pond to

the NOAA ER-M screening value results in QIs of 550 and 23, respectively. The ER-M

screening value represents the median concentration that caused effects to tested benthic

organisms.

The effects of aldrin and dieldrin at the detected concentrations in South Pond may

have serious impacts to aquatic habitat viability. These concentrations may result in the

decrease in viability of the benthic community in the South Pond, which, in turn, would

result in loss of food sources for waterfowl, fish, and other wildlife.

4.2 Risks to Terrestrial Wildlife 4.2.1 White-Tailed Deer

Potential risk to the white-tailed deer inhabiting the uplands and wetlands adjacent

to South Pond was estimated by comparing the estimated daily dose of aldrin and dieldrin

(in wetland soils and drainage ditch soils) with the TRVs derived for the deer. As shown

in Table 4-1, the quotient indices for aldrin and dieldrin in the deer are below unity.

These QIs would suggest little risk to the deer from aldrin and dieldrin.

4.3 Uncertainty There are a number of points in the decision making process of an wildlife toxicity

assessment where there are inherent uncertainties. As a result, it is often necessary to

make certain assumptions to facilitate the preparation of the risk assessment. When data

is lacking, conservative assumptions are made to be protective of the environment.

Des Moines TCE-OU4 - Ecological Risk Assessment / Decembers, 1994 19

4.0 Risk Characterization

The risk characterization portion of the WTA estimates baseline risks to specific

receptors or individuals representative of a trophic groups of receptors based on the

information gathered during the exposure and toxicity assessments. In instances where

ARAR's have been developed for specific chemicals of concem, a comparison of ARAR's

and risk based remediation goals will be made. Also included in the risk characterization

section, will be a evaluation of the uncertainty' associated with the calculations and

assumptions made throughout the WTA.

Risk characterization is the final phase of a risk assessment. It is at this phase that

the likelihood of adverse effects occurring as a result of exposure to a stressor are

evaluated.

Quotient indices (QIs) were calculated in sediment for benthic macroinvertebrates and

in surface soil for terrestrial receptors. A quotient index of less than 1 is not considered

to be indicative of risk. Quotient indices exceeding 1, but less than 10 indicate a small

risk of ecological effects. Quotient indices exceeding 10 indicate a significant risk of

ecological effects. Quotient indices exceeding 100 indicate a critically significant risk of

ecological effects.

It is important to note that the actual or estimated NOAEL values used in establishing

risk in this WTA are representative of chronic effects. As such, the HQ generated for the

contaminants at the site may not be indicative of current conditions, rather, those that may

occur over time. As the HQ increases, the risk of long-term, chronic effects on the

receptors of concern would increase.

4.1 Risks to Aqua t i c Wi ld l i fe 4.1.1 Beaver

Potential risk to the beaver inhabiting the South Pond and adjacent wetland area was

estimated by comparing the estimated daily dose of aldrin and dieldrin (in wetland soils)

with the TRVs derived for the beaver. As shown in Table 4-1, the quotient indices for

aldrin and dieldrin in the beaver are less than unity (1). These QIs would suggest little

risk to the beaver and other aquatic mammals that may be present at the site.

4.1.2 Mallard Potential risk to the mallard, which may inhabit South Pond was estimated by

comparing the estimated daily dose of aldrin and dieldrin (in South Pond sediment) with

Des Moines TCE-OU4 - Ecological Risk Assessment Decembers, 1S94 18

was 500. The TRV for aldrin in the mallard was estimated to be 1.04 mg/kg-day. The

TRV for dieldrin in the mallard was estimated to be 0.76 mg/kg-day.

LD30 ^500 - > TRV„,„„,

3.3.4 Benthic Macroinvertebrate Community The toxicity of dieldrin to benthic macroinvertebrates was assessed by comparing

sediment concentrations in South Pond to the National Oceanic and Atmospheric

Administration (NOAA) lowest observed effects-range (ER-L) toxicological data for

benthic macroinvertebrates in aquatic sediments. The NOAA ER-L for dieldrin in aquatic

sediments is 0.02 parts per billion (ppb) (USEPA, 1991).

There was no NOAA or other toxicological data located for aldrin to benthic

macroinvertebrates. Since aldrin is chemically related to dieldrin, the dieldrin NOAA ER-

L was used for aldrin for the purposes of this WTA.

Des Moines TCE-OU4 - Ecological Risk Assessment December 9, 1994 17

families within the order. Additionally, the diet ;ind digestive tract of these two species

is somewhat different. Because of the uncertainty involved in extrapolating between

species, a safety factor of 5 was applied to the rat LOAELs to develop NOAELs and a

safety factor of 5 was applied to these NOAELs to derive TRVs for the beaver. The TRV

for aldrin in the beaver was estimated to be 0.001 mg/kg-day. The TRV for dieldrin in

the beaver was estimated to be 0.0002 mg/kg-day.

LOAEL„, -5 - > NOAEL,, ^ 5 - > TRV,„„,

3.3.2 White-Tailed Deer Chemical-specific toxicity data for aldrin in the white-tailed deer was not found in

the literature. Alternatively, a TRV for aldrin was; extrapolated from the LOAEL values

for laboratory rats, 0.025 and 0.005 mg/kg-day, respectively. The rat and the white-tailed

deer are both members of the phylogenic class Mammalia although they are members of

different orders within this class. Additionally, the diet and digestive tract of these two

species is somewhat different. Because of the uncertainty involved in extrapolating

between species, a safety factor of 5 was applied to the rat LOAEL for aldrin to develop

a NOAEL and a safety factor of 5 was applied to this NOAELs to derive a TRV for the

white-tailed deer. The TRV for aldrin in the deer was estimated to be 0.001 mg/kg-day.

LOAEL,, ^5 - > N0AEL,3, ^ 5 - > TRV,„,

Chemical-specific toxicity data for dieldrin in the white-tailed deer was not found in

the literature,; however, there was specific toxicity data for the mule deer, a member of

the same genus as the white-tailed deer. The TRV for dieldrin was extrapolated from the

minimum LDjp for the mule deer, 100 mg/kg. The safety factor for converting the LDJQ

to a chronic NOAEL was 500. The TRV for dieldrin in the deer was estimated to be 0.2

mg/kg-day.

LD30 ^500 - > TRV,„,

3.3.3 Mallard

Chemical-specific toxicity data for aldrin and dieldrin in the mallard was found in the

literature. The TRV for aldrin and dieldrin in young mallards was extrapolated from the

LD50, 520 and 381 mg/kg. The safety factor for converting the LDjo to a chronic NOAEL

Des Moines TCE-OU4 - Ecological Risk Assessment December S, 1994 16

the LD50 by a safety factor of 5. This safety factor is based on an analysis of

dose-response data for pesticides. A dose-response five times lower than the LDj^ would

be expected to result in a mortality rate of about 0.1% under typical conditions, and up

to 10% when the responses in the test population are highly variable. Protection of 90 to

99% of a population is expected to provide an adequate margin of safety. In the absence

of similar information from chronic studies, a safety factor of 5 was also applied in the

extrapolation of a chronic lowest-observable-adverse-effect-level (LOAEL) to a chronic

no-observable-adverse-effect-level (NOAEL). This type of approach has been routinely

used in aquatic toxicology, and was also adopted for use in this assessment.

There is currently no USEPA guidance available for the extrapolation of acute

toxicity data to chronic NOAELs. However, several studies have evaluated the

relationship between LDjg values and chronic NOAELs for the same chemical in small

mammals (Venmen and Flaga, 1985; Layton et al., 1987) and have found that the ratio

of LD50 to a chronic NOAEL (LDj/NOAEL) typically ranges from 10 to 1000. For the

purpose of this ecological assessment, a safety factor of 500 (5 for LD50 —> acute toxicity

threshold, and 100 for acute toxicity threshold —> chronic NOAEL) was used to

extrapolate from an LDSO concentration to a chronic NOAEL. An additional safety factor

of 5 was applied in these cases when the test species differed from the target species

selected for the site, since animal species can exhibit differences in sensitivity to a

chemical.

3.3 Ecological Effects Characterization The potential ecological effects to the benthic macroinvertebrate community of South

Pond was evaluated by comparing known contaminant concentrations in sediment to EPA,

State, or other appropriate regulatory screening values. The potential ecological effects

to the three terrestrial target species was evaluated by comparing the known contaminant

concentrations to existing scientific literature and by comparing the exposure doses to

TRVs. These TRVs and screening values are the measurement endpoints used in this

WTA and are summarized in Table 3-1.

3.3.1 Beaver Chemical-specific toxicity data for the beaver was not found in the literature.

Alternatively, beaver TRVs for aldrin and dieldrin were extrapolated from the LOAEL

values for laboratory rats, 0.025 and 0.005 mg/kg-day, respectively. The rat and the

beaver are both members of the order Rodentia, although they are members of different


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3.0 Ecological Effects Assessment

3.1 Toxicity Characterization In this ecological effects assessment, information on the toxicity of aldrin and dieldrin

to ecological receptors is presented. The toxicity information is used in the development

of toxicological reference values (TRVs) (i.e., acceptable daily doses or media

concentrations) for selected target species. A comprehensive literature and database search

was performed to identify relevant toxicological data for the target receptors. The data

sources that were reviewed included:

Chemical Abstracts (CA Service)

Integrated Risk Information System (IRIS)

Health Effects Assessment Summary Tables (HEAST)

Hazardous Substances Data Base (HSDB)

Phytotox

In addition to these databases, toxicity information was obtained from a variety of

primary literature sources as presented throughout the following subsections.

3.2 Toxicological Safety Factors Species-specific toxicity data for target wildlife species often were not available for

the chemicals of potential concern. Thus, where possible, toxicity values from the

literature were selected using the most closely related species. Data for chronic toxicity

were preferentially used, when available. Toxicity values selected for the assessment were

the lowest exposure doses reported to be toxic or the highest doses associated with no

adverse effect.

Since toxicity data for terrestrial wildlife are not nearly as complete as that found for

laboratory and aquatic species, extrapolation of toxicity data from other animal studies is

often necessary. Because of the uncertainty associated with these extrapolations, safety

factors are applied to toxicological data to derive TRVs.

For those chemicals for which only acute lethality values were available, toxicity

values for this assessment were derived by dividing the acute toxicity value by the

appropriate safety factors. Based upon the guidajice provided by the USEPA (1986c), a

median lethal dose (LDjg) may be extrapolated to an acute toxicity threshold by dividing

Des Moines TCE-OU4 - Ecological Risk Assessment Decembers, 19S4 14

2.3.4 Mallard Exposure The mallard feeding rate was estimated to be approximately 337.5 grams/day

(USEPA, 1993). The mallard is omnivorous, obtaining approximately 30% of its diet

from plant sources and the remaining 70% from insects and benthic invertebrates

(USEPA, 1993). The body weight of the mallard is estimated to be approximately 1.03

kg (USEPA, 1993). The home range of the mallard is approximately 540.0 hectares

(USEPA, 1993). The mallard is estimated to incidentally ingest soil at a rate of

approximately 2.0% of its overall ingestion rate or 6.75 grams/day (USEPA, 1993).

2.3.5 Benthic Community Exposure The NOAA ER-L criteria will be used as a benchmark to establish adverse effects to

the benthic community for South Pond sediment aldrin and dieldrin concentrations.

Actual exposure surrogate organisms "in South Pond will not be determined for this

evaluation since the screening values used to develop QIs are based on field toxicity

studies, and there is little specific information available in the scientific database.


The wildlife species selected included both herbivorous and insectivorous species,

however, only vegetation ingestion and incidental soil ingestion were examined in this

WTA. There is limited information addressing invertebrate and insect uptake and

bioaccumulation of contaminants; therefore, an accurate determination of the contaminate

dose from this portion of the diet would not be practical.

Other exposure pathways at the site include dermal absorption and inhalation. Both

of these exposure pathways are difficult to qu.uitify due to a lack of scientific data.

Additionally, aldrin and dieldrin are not expected to significantly volatilize and would not

be expected to present an inhalation hazard to the species of concern. Therefore, for the

purposes of this WTA, these exposure pathways were not evaluated.

2.3.1 Plant Uptake Plant tissue concentrations of aldrin and dieldrin were estimated by using soil to plant

transfer coefficients (TCv), developed from the octanol/water coefficient for each chemical

(Travis 1988; Howard, 1991). The TCv generally indicated the amount of contaminant

present in plant tissues given a known soil concentration. The values for TCv are shown

on the worksheets in Tables 2-2, 2-3, and 2-4.

2.3.2 Beaver Exposure The beaver feeding rate was estimated from a general feeding rate value for

herbivorous mammals to be 772.72 grams/day (USEPA, 1993). The beaver is a strict

herbivore, obtaining 100% of its diet from plant sources (USFWS, 1983). The body

weight of the beaver is estimated to be approximately 20.0 kg (Burt, 1976). The home

range of the beaver is approximately 0.17 hectares (USFWS, 1983). The beaver is

estimated to incidentally ingest soil at a rate of approximately 2.4% of its overall


2.3.3 White-Tailed Deer Exposure The white-tailed deer feeding rate is 1,600 grams/day (Dee, 1991). The white-tailed

deer is a strict herbivore, obtaining 100% of its diet from plant sources (Burt, 1976). The

body weight of the deer is estimated to be approximately 45.40 kg (Burt, 1976). The

home range of the deer is approximately 183.70 hectares (Dee, 1991). The deer is

estimated to incidentally ingest soil at a rate of approximately 1.0% of its overall



2.0 Exposure Assessment

The exposure assessment is conducted to estimate the magnitude of actual or potential

exposure of specific receptors to contaminants associated with the site along with the

related uncertainties involved with the assessment. Development of these exposure route

is discussed in Section 1.5 of this WTA. A graphical ecological conceptual model

illustrating the exposure routes assessed in this WTA is presented in Figure 1-2.

2.1 Ecological Chemicals of Potential Concern The sediments and surface soils of the South Pond, Forested Wetland, and the

Drainage Ditch were sampled and analyzed for a wide range of chemicals. However, the

most potentially significant chemicals, in terms of ecotoxicology, were determined to be

aldrin and dieldrin. While other contaminants were present in the area evaluated, these

were not significant toxicants when compared to aldrin and dieldrin.

2.2 Exposure Point Concentrations The exposure point concentration is the concentration of a chemical in an

environmental media to which a specific receptor is exposed. It is generally calculated

using statistical methodology from a set of data derived from environmental sampling.

There were relatively few samples obtained in locations necessary to fully evaluate the

exposure point concentrations. Therefore, for the purposes of this WTA, the average of

the concentrations obtained in each of the three habitats of concern was used as the

exposure point concentration.

There were approximately two sediment samples, four wetland surface soil samples,

and four drainage ditch composite surface soils used in this WTA (BVWS, 1994; Miles

Corp., 1994). The exposure point concentration for aldrin and dieldrin in each habitat

under evaluation are shown in Table 2-1.

2.3 Exposure and Intake Assumptions Total exposure of three terrestrial target wildlife species (beaver, white-tailed deer,

and mallard) to aldrin and dieldrin in surficial soils and sediments was determined by

estimating the chronic daily intake (CDI) dose. The equations used to estimate the CDI

vary slightly between species. These exposure equations for each of the three wildlife

species are shown on the worksheets in Tables 2-2, 2-3, and 2-4.


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soils and sediments will be determined by estimating the chronic daily intake (CDI) dose.

This CDI will be compared to the TRV to determine if the ECOPC concentrations are

protective of species viability for the wildlife species of concem.

1.6.2.2 Terrestrial Receptor Measurement Endpoints. Terrestrial habitats present

include the Des Moines TCE-0U4 drainage ditch. The measurement endpoint, to be used

in evaluating the effects of ECOPCs on the viability of the target wildlife species, will

include Toxicity Reference Values (TRV) developed from No-Observable-Adverse-Effect-

Level (NOAELs) or Lowest-Observable-Adverse-.Effect-Levels (LOAELs) obtained from

the Integrated Risk Information System (IRIS, 1993) or other toxicological data in the

literature. Total exposure of the wildlife species of concern (white-tailed deer) to

ECOPCs in surficial soils will be determined by estimating the chronic daily intake (CDI)

dose. This CDI will be compared to the TRV to determine if the ECOPC concentrations

are protective of species viability for the wildlife species of concem.


Forested Wetlands


Drainage Ditch


Loss of species and community viability is defined for the purposes of this

investigation as the loss of any species or group of species due to the direct or indirect

effects of a release of substances from the site. There is a potential for adverse effects

to terrestrial piscivores (raccoon and kingfishers); however, there is insufficient sample

data to estimate the exposure to these species.

1.6.2 Measurement Endpoints Measurement endpoints are those used in the field to approximate represent or lead

to the assessment endpoint. Because the direct measurement endpoint of habitat diversity

is incapable of being protective of the habitat until after the quantifiable degradation has

occurred, it proves an inadequate endpoint for the purposes of this study. Rather, the

most convenient expression of risk should be a probability that such an event will occur

or a simple quotient index (Ql) developed from a comparison of exposure doses or

concentrations to the toxicity information available for each chemical. This toxicity

information will be the measurement endpoint for the WTA.

1.6.2.1 Aquatic Receptor Measurement Endpoints. Aquatic habitats present include the forested wetland and South Pond. The measurement endpoint to be used in

evaluating the effects of ECOPCs on the viability of the benthic community will be the

NOAA Effects Range-Low (ER-L) screening values for aquatic sediments (USEPA,

1991). The maximum concentration of ECOPCs in sediments will be compared to the

measurement endpoint to determine if the concentrations of ECOPCs are protective of

total benthic community viability for South Pond.

The measurement endpoint, to be used in evaluating the effects of ECOPCs on the

viability of the target wildlife species, will include Toxicity Reference Values (TRV)

developed from No-Observable-Adverse-Effect-Level (NOAELs) or Lowest-Observable-

Adverse-Effect-Levels (LOAELs) obtained from the Integrated Risk Information System

(IRIS, 1993) or other toxicological data in the literature. Total exposure of the wildlife

species of concern (beaver, white-tailed deer, and the mallard) to ECOPCs in surficial


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was evidence observed on trees that the beaver feeds in this area. The beaver may

also feed on roots and tubers of emergent vegetation growing around South Pond.

1.5.1.2.2 White-tailed deer. The white-tailed deer (Odocoileus virginianus), a

herbivorous, terrestrial mammal, was used to determine the exposure of terrestrial

herbivores to contaminated sediments in the Forested Wetland. The white-tailed deer

may spend a portion of its time feeding on shrubs, grasses, and leaves in wetlands

and uplands. There was evidence of an abundant deer population observed during

the site investigation.

1.5.1.3 Drainage Ditch. The Drainage Ditch is part of the Upland Open Field habitat,

which is primarily a carnivore/grazer habitat; however, there are no known carnivorous

species present on the site. These areas, in the case of this site, are more accurately

represented by the grazer food chain. Accordingly, the white-tailed deer was selected as

wildlife species of concern subject to exposure to contaminated ditch soils. The habitat

requirements and habitat area discussed in Section 1.5.1.2.2.

1.6 Endpoints The ecological significance of the various habitats and wildlife species of concern

will be examined and appropriate goals or assessment endpoints for that value will be

determined. After determining the appropriate assessment endpoints, functional

measurement endpoints will be chosen to represent these assessment endpoints.

1.6.1 Assessment Endpoints Assessment endpoints are those describing the effects that drive decision making,

such as reduction of key populations or disruption of community structure. Assessment

endpoints for an wildlife toxicity assessment must be capable of being represented by

quantifiable measurement endpoints. They must also be protective of the value of the

various habitats of concern. With this in mind, the assessment endpoints chosen for the

Des Moines TCE-0U4 Superfund Site are:

South Pond

Omnivorous Species Viability

Macroinvertebrate Community Viability

Des Moines TCE-OU4 - Ecological Risk Assessment December 9, 1994

For vegetation, the amount of a contaminant can be estimated based on the soil or

sediment concentration and the chemical properties of each particular chemical. The

vegetation bioconcentration factor is inversely proportional to the square root of the

octanol-water coefficient for each ECOPC (Travis, 1988).

A graphical representation of the relationship between the contaminated surface soils

and sediments and the wildlife species of concem is presented in the ecological

conceptual model shown in Figure 1-2.

1.5.1.1 South Pond. The South Pond is a generally stagnant aquatic habitat represented

by both grazer and detritus food chains. The detritus food chain will be evaluated by

direct comparison of contaminant concentrations in sediments to benthic toxicity data.

The mallard, an omnivore representing the grazer food chain, will be used to model

exposure to contaminated South Pond sediments.

1.5.1.1.1 Mallard. The mallard (Anas platyrhynchos), an omnivorous bird, will be

used to determine the exposure of omnivores to contaminated sediments and

vegetation in South Pond (EPA, 1993). The mallard is commonly found in ponds,

lakes, and marshes (Bull and Farrand, 1988). The mallard feeds primarily on green

vegetation, aquatic roots and tubers, seeds, snails, and benthic invertebrates by

dabbling and filtering through soft sediments (EPA, 1993); however, only vegetation

ingestion and incidental soil ingestion were examined in this WTA. There is limited

information addressing invertebrate and insect uptake and bioaccumulation of

contaminants; therefore, an accurate determination of the contaminate dose from this

portion of the diet would not be practical.

1.5.1.2 Fores ted Wetlands. The Forested Wetland is primarily carnivore/grazer

habitat; however, there are no known carnivorous species present on the site. These areas,

in the case of this site, are more accurately represented by the grazer food chain.

Accordingly, the beaver and the white-tailed deer were selected as wildlife species of

concern subject to exposure to contaminated surface soils in the wetland.

1.5.1.2.1 Beaver. The beaver (Castor canadensis), a herbivorous, semi-aquatic

mammal, will be used to determine the exposure of herbivores to contaminated

sediments in the Forested Wetland. One beaver lodge was observed in the

southeastern portion of South Pond, in the Forested Wetland area. Additionally, there

Des Moines TCE-OU4 - Ecological Risk Assessment / December 9, 1994 7

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1.5 Exposure Pathway and Receptor Analysis A migration pathway is defined, for the purpose of this WTA, as a route by which

a contaminant may be transported from the site to the exposure point for a particular

wildlife species or habitat of concern. An exposure route is defined, for the purposes of

this WTA, as the means by which contaminants in a specific media enter a wildlife

species of concem.

Contaminants from the Des Moines TCE site have been shown to have migrated to

the South Pond, Forested Wetlands, and the Drainage Ditch from South Pond based on

the analysis of surface soil and sediment samples (BVWS, 1994; Miles, 1994).

The exposure routes for contaminants in these habitats to representative wildlife

species may include: 1) ingestion, 2) respiration, and 3) absorption. Ingestion of

contaminants occurs when an organism ingests contaminated food, water, or other

contaminated media through direct or incidental ingestion. Respiration of contaminants

occurs when an organism absorbs contaminants through the respiratory organs such as the

skin, gills, or lungs. Contaminants are also absorbed directly through the skin, eyes, and

other mucous membranes.

Data are lacking concerning the inhalation and absorption exposure and uptake rates

for chemicals in wildlife species. Therefore, in this WTA, the exposure of wildlife to

contaminants will be solely based in the direct and incidental ingestion of contaminated

media and food by the wildlife species of concern. Since surface water samples were not

evaluated in this WTA, direct and incidental ingestion of contaminated water will not be

assessed in this WTA. As a result of these factors, the WTA will only address the direct

and incidental ingestion of contaminated sediments from each habitat, and may

underestimate the overall risks to those species of concern.

1.5.1 Exposure to Species/Habitats of Concern Based on the findings of the habitat evaluation and the environmental analytical data

available at the site, there were three habitats of concern evaluated in this WTA including

the South Pond, the Forested Wetlands, and the Drainage Ditch. The potential exposure

to actual or surrogate species indicative of the most critical trophic feeding groups was

modelled for each habitat of concern.

No samples of vegetation were analyzed, therefore, concentrations of ECOPCs in

these organisms are unknown. However, as essential points of potential ECOPC exposure

in the food chain, it becomes essential to predict the concentrations of ECOPCs in these

organisms based on the known sediment concentrations.

Des Moines TCE-OU4 - Ecological Risk Assessment j December 9, 1994 6

Pond. There were no tracks or recent signs of beaver in the study area. Beaver eat bark

and small twigs of maples and cottonwood, both species common near the beaver dam.

Songbirds were heard in the upland forests and forested wetlands within the study

area. Individual species could not be identified during the habitat evaluation. Songbirds

generally feed on insects and the seeds of herbaceous vegetation. There were no

songbirds observed or heard in the open field or emergent wetland areas, probably due

to a lack of cover.

Five to seven American crows were observed in the eastern forest areas, roosting in

the canopies of cottonwood trees. Crows eat earthworms, insects, agricultural crops, and

herbaceous seeds; although they will occasionally eat anything available. American crows

were not observed in the other habitats within the study area.

The tracks of a housecat were observed in the open field habitat, from the urban areas

to the north under the fence, and onto the Building 4/5 site. These tracks led to the

building itself, which may indicate that a family of feral cats is present at the site. Feral

cats generally feed on small rodents and birds. The presence of feral cats at the site may

be used to infer the presence of these prey animals at the site.

A flock of Canada geese were observed flying over the site. Canada geese usually

utilize pond and lake habitats, where they feed on leaves and tubers of emergent wetland

vegetation. The South Pond area may provide suitable grazing and resting habitat for

flocks of geese.

1.4.5 Rare, Threatened, and Endangered Species

Information collected during the site investigations did not indicate the presence of

any threatened or endangered species on or near the site. No threatened or endangered

species were observed during the site investigations (BVWS, 1994).


species dominant within this area include Japanese knotweed (Polygonum cuspidalum),

blackberry (Rubus sp.), wild rose (Rosa sp), and grasses (Poacea). There was visible

evidence that this area is highly utilized by a large deer herd as a feeding, breeding, and

resting area.

The second large block of upland forest is located along the southwestern boundary

of the study area. The overstory in this upland forest was dominated by silver maple, red

maple (Acer rubrum), sugar maple (Acer saccharum), white ash, American elm, and black

cherry (Prunus serotina). The dominant shrub, sapling, and vine species include

American elm and silver maple saplings and grape. There were no herbaceous species

observed within this area.

1.4.3.2 Upland Open Field. There was one large area of upland open field located

west and south of Building 4/5 and a small strip east and south of Building 4/5. These

areas were completely void of trees, saplings, and shrubs, and contained only herbaceous

species. These species included foxtail grass (Setaria sp.), and unidentified grasses. A

dry drainage channel runs from north to south along this habitat at its eastern boundary.

1.4.4 Wildlife Usage

Wildlife observed or inferred on or near the study area included white-tailed deer

(Odocoileus virginianus), beaver (Castor canadensis), songbirds (Passeriniformes),

American crows (Corvus brachyrhynchos), housecat (Felis domesticus), and Canada goose

(Branta canadensis). No other signs of any other wildlife species were observed during

the habitat evaluation. Wildlife was observed in all habitats in the study area.

Deer were the most common wildlife species in the study area. Deer were observed

in all habitats except the aquatic habitat. Based on observation of tracks, ruts, and

bedding, the deer appear to utilize the upland forest areas for sleeping areas, feeding, and

breeding. Deer appear to utilize the other habit.it on the site to pass between forested

areas. A large portion of the eastern upland forest area appears to provide excellent

habitat for a large (10-20) deer herd. This area was almost completely covered with deer

tracks, scat, urine, ruts, and bedding areas. The vegetation in this habitat provides an

excellent food source for deer, which generally feed on twigs, shrubs, fungi, grass, and

herbs.

Chewed trees, saplings, and a dam were evidence of a beaver population in the study

area. The chewed saplings and dam were located in an area of emergent and forested

wetlands in the southern end of the South Pond. The dam was partially within the South


1.4.1 Aquatic Habitat The aquatic habitat observed within the study area consists of South Pond, the

Emergent Wetlands, and the Forested Wetlands.

1.4.1.1 South Pond. The aquatic habitat observed within the study area consists of

the South Pond. South Pond was frozen and covered with approximately 14 to 16 inches

of ice and an additional eight inches of snow during the site reconnaissance. As a result,

very little information concerning the physical and biological components of this habitat

were obtained. The water depth in the center of South Pond was approximately 3 feet

deep. The substrate of the pond was observed to be a very soft sediment that had a

strong petroleum-like odor.

1.4.1.2 Emergent Wetlands. The emergent wetland areas were located along the

fringes of the South Pond, around the low channel that periodically drains the pond to the

east, and in an open area at the northern corner of the low-lying areas. These emergent

wetlands were dominated by smartweeds (Polygonum spp.), cattail (Typha latifolia), and

reed canary grass (Phlaris arundinacea).

1.4.1.3 Fores ted Wetlands. The forested wetlands were located in a contiguous band

stretching from the southern bank of the South Pond, along the west bank, and just around

the northern corner of the pond. The dominated overstory species in the forested wetlands

were silver maple, green ash (Fraxinus pennsylvanica), white ash (Fraxinus americana),

and American elm (Ulmus americana). Dominant shrub and vine species included red

mulberry (Morus rubra), grape (Vitis sp.), and silver maple saplings.

1.4.3 Terrestrial Habitat The terrestrial habitat observed within the study area consists of upland forest and

upland open field.

1.4.3.1 Upland Forest . There were two large blocks of upland forest located in the

study area which were dominated by different tree species and subject to different

physical conditions.

The eastern upland forest area had an overstory dominated by cottonwood (Populus

deltoides). The dominant shrub, sapling, and vine species include cottonwood saplings,

red mulberry, silver maple, grape, and poison ivy (Toxicodendron radicans). Herbaceous


1.3 Chemicals Data Collection and Evaluation Ecological chemicals of potential concern (ECOPCs) may often include more

individual chemicals than the human health assessment because the screening criteria for

human health do not apply to ecological receptors.

Analytical data from surface soils and sediments was used to estimate the ecological

risks at the site. The surface soil data was grouped into wetlands concentrations and

concentrations in the drainage ditch, from South Pond. Sediment data was only obtained

for the sediments within South Pond. There were approximately two sediment samples,

four wetland surface soil samples, and four drainage ditch composite surface soils used

in this WTA (BVWS, 1994; Miles Corp., 1994). The development of the ECOPCs is

addressed in detail in Section 2.0 of this WTA.

1.4 Habitat Evaluation The Habitat Evaluation was performed in February 1994 as part of Operable Unit

4 of the site remediation under the BLACK & VEATCH Waste Science, Inc. (BVWS)

TES 9 contract with the U.S. Environmental Protection Agency - Region VII (Kcuisas

City) (BVWS, 1994).

The study area included in this Habitat Evaluation report is shown in Figure 1-1. The

study area at the Des Moines TCE site is located within a rounded triangle formed by

railroad tracks encircling an area in the southern portion of the Dico site. This northern

portion of this study area has been developed and consists of Building 4/5, dirt roads and

parking areas, and railroad tracks. The remainder of the study area is largely undeveloped

although it has been impacted by activities at and around the Dico and DiChem facilities.

Five separate types of sub-habitat were observed on the site including: (1) Aquatic (South

Pond), (2) Emergent Wetlands, (3) Forested Wetlands, (4) Upland Forest, and (5) Upland

Open Field. The location of this habitat is shown in Figure 1-1.

The entire study area appears to have been impacted by the widespread flooding that

occurred during the summer months of 1993. Flood marks, suspended vegetative

material, and an oily film were observed at a uniform elevation on vegetation throughout

the study area. The height of this flood line varied from four to over ten feet, depending

on the ground elevation. This flood may have caused additional contamination from off-

site sources, shifting of contamination on the site, and loss or change of ecological

habitat.


1.0 Problem Formulation

A semi-quantitative baseline wildlife toxicity assessment (WTA) has been performed

for the Des Moines TCE-0U4 site to determine if there is any present or potential risk

to the environment from previous site activities. This evaluation is an assessment of

baseline risk which was developed by evaluating data collected during the RI and other

previous investigations.

1.1 Objectives of the WTA This WTA evaluates the potential risks to the environment due to releases of

contaminants at the site (USEPA, 1992). The general objective of the WTA is to provide

the information necessary to assist in the decision-making process at remedial sites.

Specific objectives of the WTA include:

• Identify and provide analysis of baseline risks (defined as risks that might exist

if no remediation or institutional controls were applied at the site);

Provide a basis for determining the cleanup levels of chemicals that will provide

adequate protection of public health or the environment;

1.2 Scope of the WTA The goal of this WTA is to provide information on threats to the natural environment

associated with contaminants or with actions designed to remediate the site. The WTA

is also intended to reduce the inevitable uncertainty associated with understanding the

environmental effects of a site and its remediation, and to give specific boundaries to that

uncertainty. Information provided by the WTA may be used to:

• Decide if remedial action is necessary based on ecological considerations

Evaluate the potential ecological effects of the remedial action itself

• Provide information necessary for mitigation of the threat

• Design monitoring strategies for assessing the progress and effectiveness of

remediation


Figures and Tables

Figures

Figure 1-1. Sample and Habitat Location Map Figure 1-2. Ecological Conceptual Site Model

Tables

Table 2-1. Aldrin and Dieldrin Exposure Point Concentrations Table 2-2. Ingestion Dose Worksheet for the Beaver Table 2-3. Ingestion Dose Worksheet for the White-Tailed Deer Table 2-4. Ingestion Dose Worksheet for the Mallard

Table 3-1. Measurement Endpoints for Target Species/Communities

Table 4-1. Quotient Indices for Wildlife Table 4-2. Quotient Indices for Benthic Macroinvertebrates

•


Contents (cont'd)

3.0 Ecological Effects Assessment 14 3.1 Toxicity Characterization 14 3.2 Toxicological Safety Factors 14 3.3 Ecological Effects Characterization 15

3.3.1 Beaver 15 3.3.2 White-Tailed Deer 16 3.3.3 Mallard 16 3.3.4 Benthic Macroinvertebrate Community 17

4.0 Risk Characterization 18 4.1 Risks to Aquatic Wildlife 18

4.1.1 Beaver 18 4.1.2 Mallard 18 4.1.3 Benthic Macroinvertebrate Community 19

4.2 Risks to Terrestrial Wildlife 19 4.2.1 White-Tailed Deer 19

4.3 Uncertainty 19 4.3.1 Endpoint Comparison Uncertainty 20 4.3.2 Exposure Assessment Uncertainty 20 4.3.3 Ecological Effects Assessment Uncertainty 21 4.4.4 Wildlife Toxicity Assessment Uncertainty 21

5.0 Conclusions and Ecological Significance 22 5.1 Aquatic Receptor Measurement Endpoints 22 5.2 Terrestrial Receptor Measurement Endpoints 22 5.3 General Conclusions 23 5.4 Recommendations 23

6.0 References 24


Contents Page N°.

1.0 Problem Formulation 1 1.1 Objectives of the WTA 1 1.2 Scope of the WTA 1 1.3 Chemicals Data Collection and Evaluation 2 1.4 Habitat Evaluation 2

1.4.1 Aquatic Habitat 3 1.4.1.1 South Pond 3 1.4.1.2 Emergent Wetlands 3 1.4.1.3 Forested Wetlands 3

1.4.3 Terrestrial Habitat 3 1.4.3.1 Upland Forest 3 1.4.3.2 Upland Open Field 4

1.4.4 Wildlife Usage 4 1.4.5 Rare, Threatened, and Endangered Species 5

1.5 Exposure Pathway and Receptor Analysis 6 1.5.1 Exposure to Species/Habitats of Concern 6

1.5.1.1 South Pond 7 1.5.1.1.1 Mallard 7

1.5.1.2 Forested Wetlands 7 1.5.1.2.1 Beaver 7 1.5.1.2.2 White-tailed deer 8

1.5.1.3 Drainage Ditch 8 1.6 Endpoints 8

1.6.1 Assessment Endpoints 8 1.6.2 Measurement Endpoints 9

1.6.2.1 Aquatic Receptor Measurement Endpoints 9 1.6.2.2 Terrestrial Receptor Measurement Endpoints 10

2.0 Exposure Assessment 11 2.1 Ecological Chemicals of Potential Concern 11 2.2 Exposure Point Concentrations 11 2.3 Exposure and Intake Assumptions 11

2.3.1 Plant Uptake 12 2.3.2 Beaver Exposure 12 2.3.3 White-Tailed Deer Exposure 12 2.3.4 Mallard Exposure 13 2.3.5 Benthic Community Exposure 13


FINAL

WILDLIFE TOXICITY ASSESSMENT

for the

DES MOINES TCE-OU4 SITE

Des Moines, lowa

Prepared for:

U.S. Environmental Protection Agency Region Vll - Kansas City, MO

Prepared by:

BLACK & VEATCH WASTE SCIENCE, INC. Philadelphia, PA

December 9, 1994

BLACK & VEATCH Waste Science, Inc. Philadelphia Office

MEMORANDUM Page 3

USEPA - Region Vll B&V Project 71400.032 Des Moines TCE - 0U4 December 9, 1994 Revisions to WTA (formerly BERA) based on EPA Cincinnati Comments

Comment #12 We have referenced the FWS site investigation memorandum which discussed

potential remedial alternatives in Section 5.0 of the WTA. We feel this provides some more support for the discussions in this section.

Hopefully, we have sufficiently addressed all of EPA-Cincinnati's comments to your level of confidence. If you have any questions, please feel free to call me at 215/928-2203.

cc Craig Willis, BVWS-KC

BLACK & VEATCH Waste Science, Inc. Philadelphia Office

MEMORANDUM Page 2

USEPA - Region VII B&V Project 71400.032 Des Moines TCE - 0U4 December 9, 1994 Revisions to WTA (formerly BERA) based on EPA Cincinnati Comments

have no records indicating T&E on the site, but there may be better records at the local State Heritage office.

Comment #6 No response. Given the semi-quantitative nature of this WTA, we feel that the

use of the octanoiwater coefficient is sufficient to estimate plant uptake.

Comment #7 We have not discussed the inhalation exposure oral or dermal exposure to water

due to (1) a lack of water data with any "hits" for aldrin and dieldrin, (2) a lack of scientific data to quantify the dermal exposure and inhalation pathways. Additional clarifying text has been added to Section 2.3 (p. 12) to address this comment.

Comment #8 The issue of risks to piscivores was discussed and addressed in the response to

Comment #2. Bioconcentration of chemicals is generally addressed in Section 5.4 (p. 23). Fate and transport of aldrin and dieldrin will be addressed in the RJ.

Comment #9 No response. Decomposition products will be addressed in the fate and

transport discussions in the RI.

Comment #10 No response. We have used an interspecies safety factor of 5. In the report, we

have justified our rationale for this factor. The references cited in this suggest a safety factor of 10. In terms of 'order of magnitude" there is no significant difference in the conclusions by changing this value.

Comment #11 No response. We feel that the use of a NOAEL derivation factor from a LD50

of 500 is referenceable and defensible. The reference is cited in the report.

•

5.3 General Conclusions In general, the QIs for the benthic macroinvertebrate community of South Pond are

very high, based on the concentrations of aldrin and dieldrin in South Pond sediment.

There appears to be little risk posed by the chemical concentrations in the wetlands

surface soils and drainage ditch surface soils.

The ecological effects assessment indicates that the concentrations of aldrin and

dieldrin present in the South Pond sediment may cause an increase in mortality to benthic

species and decrease abundance and diversity of benthic species.

5.4 Recommendations The conclusions of this WTA seem to suggest that there may be significant ecological

risks associated with portions of this site. Thej:e risks are significant enough that remedial

activities may be required to be protective of the environment; however, remedial

activities in the wetland and South Pond would physically alter or eliminate the habitat

it is intended to remediate.

The maintenance of the status quo will continue to allow aldrin and dieldrin, which

are both bioaccumulative, to persist in the food chain and would not be protective of fish

and wildlife (FWS, 1994). Therefore, available remedial options should reduce or

eliminate the exposure threat to contaminated sediment.

One possible remedial option may include de-watering of the pond and removal of

the contaminated sediments. This option would allow the pond to become reestablished

with a benthic community and possibly enhance the surrounding habitat. However,

excavation of sediments may result in the release of chemicals into the surrounding

environment, which may be detrimental to fish and wildlife (FWS, 1994).

Another option may involve the de-watering of the pond and covering of the

sediments with clean fill. This would also allow reestablishment of the pond habitat and

would prevent any future impacts to fish and wildlife (FWS, 1994).

Other potential options may include the filling of the South Pond, thus eliminating

the exposure risk and the habitat. This alternative would probably have a negative effect

on the surrounding wetlands, which are partially dependant on the surface water provided

by the pond.


6.0 References

BVWS (BLACK & VEATCH Waste Science, Inc.), March 1994. Data Report for South

Pond Sediment Samples SED-001 and SED-002.

BVWS (BLACK & VEATCH Waste Science, Inc.), March 1994. Des Moines TCE 0U4

Draft Habitat Evaluation Report - South Pond Study Area.

Bull and Farrand, 1977. The Audobon Society Field Guide to North American Birds -

Eastern Region, Alfred Knopf, New York, NY.

Burt, 1996. A field Guide to the Mammals of America North of Mexico, Houghton-

Mifflin Company, Boston, MA.

Dee, J.C. November 1991. "Methodology for Assessing Potential Risks To Deer

Populations: A Case Study at a Superfund Site." Paper presented at the 1991 Annual

Meeting of the Society of Environmental Toxicology and Chemistry. Abstract No. 426.

FWS (U.S. Department of the Interior, Fish and Wildlife Service). Site Visit Report of

Investigation at the Des Moines TCE site - South Pond in memorandum to the Regional

Environmental Officer from the Field Supervisor, August 4, 1994.

HEAST, March 1993. Health Effects Assessment Summary Tables. Office of Research

and Development. Office of Emergency and Remedial Response. U.S. Environmental

Protection Agency.

Howard, 1991. Handbook of Environmental Fate and Exposure Data for Organic

Chemicals. Volume III - Pesticides, Lewis Publishers, Celsea, MI.

IRIS. August 1993. Integrated Risk Information System. Accessed through Chemical

Information Systems, Inc., Baltimore, MD.

Layton, D.W., B.J. Mullon, D.H. Rosenblatt, and M.J. Small, 1987. "Derivin Allowable

Daily Intakes for Systemic Toxicants Lacking Chronic Toxicity Data". Regulatory

Toxicology and Pharmacology, 7:96-112.


Miles Corporation, July 1994. Data Report of Surficial Soil Samples from Wetland Soils

and the Drainage Ditch at the Des Moines TCE Site - 0U4.

Travis, Curtis C. and Angela Arms, 1988. "Bioconcentration of organics in Beef, Milk,

and Vegetation". Environmental Science Technology. Vol 22, No. 3

USEPA (U.S. Environmental Protection Agency), December 1993. Wildlife Exposure

Factors Handbook, Volumes I and II, Office of Health and Environmental Assessment,

Washington, DC.

USEPA (U.S. Environmental Protection Agency), February 1992. Peer Review Workshop

Report on a Framework for Ecological Risk Assessment, Risk Assessment Forum,

Washington, DC.EPA/625/3-91/022.

USEPA (U.S. Environmental Protection Agency), July 1994. Region III Interim

Ecological Risk Assessment Guidelines, Technical Support Section, Superfund Program

Branch, Philadelphia, PA.

USEPA (U.S. Environmental Protection Agency), April 1991. Suggested Guidance for

Evaluating Sediment Concentration Data, Region IV Contaminated Sediments Workgroup,

Atlanta, GA.

USEPA (U.S. Environmental Protection Agency), 1986c. Ecological Risk Assessment,

Office of Pesticide Programs, Washington DC. EPA/540/9-85/001.

USFWS (U.S. Fish and Wildlife Service), April 1983. Habitat Suitability Index Models:

Beaver, Department of the Interior, Washington DC.

Venman, B.C., and C. Flaga, 1985. "Development of an Acceptable Factor to Estimate

Chronic Endpoints from Acute Toxicity Data". Toxicol. Ind. Health. 1:261-269.

Des Moines TCE-OU4 - Ecological Risk Assessment December S, 1SS4 25

i r ' A i V J Forested Wetland Habitat

] Upland Open Field/Dirt Roads

K ^ J y ]] High Deer Concentration Area

^ — i t^ Observed Deer Paths

^ B Beaver Dam

^ Sediment Samples

f Habitat Data Recording Point

Habitat and Wildlife Location Map Des Moines TCE 0U4 Site - South Pond

BLACK & VEATCH Woste Science, Inc. 601 Walnut Street. Philodelphio. PA 10106

Habitat Evaluation 0U4 - South Pond Area

Des Moines, PoII< County, lowa

iiliiiiffliiS^

Legend:

Direct Ingestion

Incidental Ingestion

Figure 1-2 Conceptual Ecological Model Des Moines TCE - 0U4 Site

Des Moines, Iowa

Table 2-1

Aldrin and Dieldrin Concentrations at

Des Moines TCE-0U4 Wildlife Toxicity Assessment

Des Moines, lowa

Chemical Frequency of Detects Minimum Detected Concentration

Maximum Detected Concentration i

Average Concentration

Wetland Surface Soils

Pesticides/PCBs fppb) Aldrin Dieldrin

4/4 4/4

1.4 1.4

62.6 62.6

22.0 22.0

Di.scharge Ditch Composite Surface Soils

Pesticides/PCBs (ppb) Aldrin Dieldrin

3/4 4/4

8.7 640.0

53.0 7,000.0

15.4 3,085.5

South Pond Sediments

Pesticides/PCBs fppb) Aldrin Dieldrin

2/2 2/2

1,500.0 180.0

7,300.0 190.0

Notes: 1. Sediment samples used for this evaluation included SED-001, SED-002 (BVWS, 1994). 2. Surface soil samples used for this evaluation included 6, 9, 10, 11, SS/71-80, SS/81-90, SS-91-100, SS/101-120 (Mil

4,400.0 185

CS, 1994).

Des Moines TCE-OU4 - Ecological Risk Assessment December S, 19S4

Table 2-2 Ingestion Dose Worksheet for the Beaver


Exposure Equation:

[(TCv * IR) + SIR] * CSw * FI BW * CF

Species Specific Information: Factor Area of Contamination, hectares Home Range, hectares Fraction of Diet from AOC (AOC/HR) Body Weight, Kg Ingestion Rate, g/day (BW'^0.727 * 0.577) Soil Ingestion Rate, g/day (BW * 2.4%) Conversion Factor, g/kg Contaminant Concentration in Wetland Soil, mg/kg Soil to Plant Transfer Coefficient, unitless Contaminant Dose, mg/kg-day

Alsbrevigtion AOC HR Fl BW IR SIR CF CSw TCv Dose

Unit 0.30 0.17 1.00 20.00 772.72 18.55 1000.00 varies varies See belov^

Reference


CSv 148 8.65

TCv 0.021 0.098

Dose 2.57E-03 4.08E-02

Table 2-3 Ingestion Dose Worksheet for the Deer


Exposure Equation:

{(CSw * Flw) + (CSd * Fid) + [SIR * (Flw + Fid)]} * TCv *IR BW*CF

Species Specific Information: Factor Wetland Soil Area of Contamination, hectares Ditch Soil Area of Contamination, hectares Home Range, hectares Fraction of Diet from Wetland Soil (AOCw/HR) Fraction of Diet from Ditch Soil (AOCd/HR) Body Weight, Kg Ingestion Rate, g/day Soil Ingestion Rate, g/day (BW * 1.0%) Conversion Factor, g/kg Contaminant Concentration in Wetland Soil, mg/kg Contaminant Concentration in Ditch Soil, mg/kg Soil to Plant Transfer Coefficient, unitless Contaminant Dose, mg/kg-day

Abbreviation AOCw AOCd HR Flw Fid BW IR SIR CF CSw CSd TCv Dose

uoil 1.00 1.00 183.70 0.0054 0.0054 45.40 1600.00 16.00 1000.00 varies varies varies See below

Reference


CSw 1.48 8.65

CSd 0.015 3.085

TCv 0.021 0.098

Dose 6.02E-06 2.21 E-04

Table 2-4 Ingestion Dose Worksheet for the Mallard


Exposure Equation:

[(TCv * VIR) + SIR] * CSw * FI BW * CF

Species Specific Information: Factor Area of Contamination, hectares Home Range, hectares Fraction of Diet from AOC (AOC/HR) Body Weight, Kg Ingestion Rate, g/day Percentage of Vegetation in Diet Vegetation Ingestion Rate, g/day (IR * PV) Soil Ingestion Rate, g/day (BW * 2.0%) Conversion Factor, g/kg Contaminant Concentration in Pond Sediment, mg/kg CSp Soil to Plant Transfer Coefficient, unitless Contaminant Dose, mg/kg-day

Abbreviation AOC HR Fl BW IR PV VIR SIR CF CSp TCv Dose

Unit Reference 0.40 540.00 0.0007 1.03 337.50 30.0% 101.25 6.75 1000.00 varies varies See below


CSB

4.40 0.19

TCv 0.021 0.098

Dose 2.84E-05 2.24E-06

Table 3-1

Measurement Endpoints for Aquatic and Terrestrial

Receptors

Des Moines TCE-0U4 Ecological Assessment

Des Moines, lowa

Chemical

Pesticides

Aldrin

Dieldrin

Aquatic

Endpoint

NOAA

ER-L

Values

NA (0.02)

0.02

Terrestrial Endpoints

Beaver

TRV

(mg/kg-day)

0.001

0.0002

Deer

TRV

(mg/kg-day)

0.001

0.2

Mallard

TRV

(mg/kg-day)

1.04

0.76

Note:

1. NA - NOAA Screening Value is not available

Des Moines TCE-OU4 - Ecological Risk Assessment December S, 1SS4

•

Table 4-1

Quotient Indices for Wildlife Species


Des Moines, lowa

Species R

Beaver

Deer

Mallard

Contaminan:

. • \R ' - : : r .A\ i R ' •[

Aldrin

Dieldrin

Aldrin

Dieldrin

Aldrin

Dieldrin

^::Dose :\

, mg/kg/day

0.0000382

0.0000943

0.000000147

0.0000598

0.0000284

0.0000224

•TRV

0.001

0.002

0.001

0.2

1.04

0.76

R: •Effects •••

LOAEL„, modified to NOAEL t„.„

LO/>^L„, modified to NOAEL t„,„

LOAEL,., modified to NOAEL , „

LD50j,„ modified to NOAELj^„

LD50,„,^,j modified to NOAEL,„,^,<,

LD50^,!,,. modified to NOAEL„,„,

Quotient

: Index (Ql)

0.0382

0.0472

0.000147

. 0.000299

0.0000273

0.0000295

. / : : ; : ; ' ; : . ; ; ; ; : Z Q i • ; : / • • ;^ ; • • ; • • ;

0.0854

0.000446

0.0000568

Des Moines TCE-OU4 - Ecological Risk Assessment December S, 19S4

Table 4-2

Quotient Indices for the Benthic Macroinvertebrate Community of South Pond


Des Moines, lowa

Species

Benthic Macroinvertebrates

Contaminan

t

Aldrin

Dieldrin

Sediment

Concentratio

: n (ppb)

4,400

185

NOAA

ER-L

0.02

(NA)

0.02

Eff'ccts .


decreased benthic

abundance


decreased benthic

abundance

Quotient

: Index (Ql)

220,000.00

9,250.00

: S Q i

229,250.00

Des Moines TCE-OU4 - Ecological Risk Assessment Decembers, 19S4

Documents

DES MOINES TCE-0U4 SITE - Superfund Records Collections · Des Moines TCE, 0U4 BVWS Project 71400 BVWS File C.3 November 22, 1994 U.S. Environmental Protection Agency 726 Minnesota