Contaminants of Concern in Water Bodies of Puerto Rico

Carmen Hernández

Fall 2019

Honors Thesis

Summa Cum Laude

Department of Soil and Water

College of Agricultural and Life Sciences

University of Florida

University Faculty: Dr. Bala Rathinasabapathi

Abstract:

Contaminants of concern are chemical, biological, or radioactive materials found

in effluents, sediments, or other substances generated by natural phenomena or human

activities. Indicator parameters are focal contaminants of concern that are characteristic

of water quality deterioration. The purpose of this research project is to generate a report

on water quality standards and pollution mitigation by identifying contaminants of concern

and indicator parameters for wastewater effluents. This information could establish a

scheme of steps to understand wastewater effluents and define future steps necessary

to treat the water to reuse it beneficially.

The specific objectives of this research are:

• Evaluate the Puerto Rico Water Quality Assessment (2018)

• Identify the contaminants of concern and indicator parameters for specific designated

uses

• Categorize contaminants of concern by the bulk of water quality, inorganic, organic,

or metal constituents

• Identify contaminants of concern and indicator parameters for domestic wastewater

treatment plants and confined animal feeding operations

• Adverse impacts on fauna, aquatic life, and humans

• Recommendations to prevent and treat contaminants at the source of pollution

• Provide educational information to the general public in a concise and useful manner

Table of Contents

List of Tables and Figures…………………………………………………………………...…1

1. Introduction………………………………………………………………………………..….2

2. Methods…………………………………………………………………………………........3

2.1.0 Water Resources in Puerto Rico……………………………………...……....3

2.1.1 Surface Water……………………………………………………..........3

2.1.2 Groundwater………………………………………………………….….4

2.1.3 Water Uses………………………………………………………………5

2.2.0 Data Collection…………………………………………………………………..6

3. Results……………………………………………………………………………………...…7

3.1.0 Contaminants of Concern in Water Bodies…………………………………....7

3.1.1 River and Streams………………………………………………….......10

3.1.2 Lakes (reservoirs)…………………………………………………........11

3.1.3 San Juan Bay Estuary……………………………………………….…13

4. Discussion…………………………………………………………………………………..14

4.1.0 Sources of Pollution…………………………………………………………....15

4.1.1 Domestic Wastewater Treatment Plants………………………….…16

4.1.2 Confined Animal Feeding Operations………………………………..19

5. Conclusion……………………………………………………………………………….….21

6. References……………………………………………………………………………….…22

1

List of Figures and Tables

Figure 1. Surface Water Resources………………………………………………...……………4

Figure 2. Groundwater Resources…………………………………………………………..……5

Figure 3a-c. Proportions of Water Use in Puerto Rico from Surface and Groundwater………..6

Table 1. Steps Descriptions………………………………………………………………………6

Table 2. Water Bodies…………………………………………………………………………….7

Table 3. Pollution Source Groups………………………………………………………………..7

Table 4. Water Quality Standards Parameter Limits …………..…….………………………..8

Table 5. Water Quality Standards Assessment for Rivers and Streams……………………10

Table 6. River and Streams Contaminants of concern…………………………………….....11

Table 7. Water Quality Standards Assessment for Lakes (reservoirs)…………………..….12 Table 8. Lakes (Reservoirs) Contaminants of concern………………………………………..12

Table 9. Water Quality Standards Assessment for San Juan Bay Estuary…………………13

Table 10. San Juan Bay Estuary Contaminants of concern……………………………………14

Table 11. Potential Sources of Pollution………………………………………………………….15

Table 12. Wastewater Treatment Plants Contaminants of Concern…………………………..18

Table 13. Confined Animal Feeding Operations Contaminants of Concern……………….….20

2

1. Introduction

Sustainability is defined by the United States National Environmental Policy Act of 1969 (NEPA)

as “create and maintain conditions, under which humans and nature can exist in productive harmony,

that permit fulfilling the social, economic, and other requirements of present and future generations”

(Sustainability Primer, 2019). A sustainable approach consists of three pillars: environmental, social,

and economic. Identifying contaminants of concern, mitigating water pollution, implementing best

management practices, and reusing water could have a positive effect on the three components of the

sustainability approach. First, the environmental pillar covers the identification of the contaminants

present in rivers, streams, lakes, and the San Juan Bay Estuary, and possible solutions to mitigate

pollution inputs in these water bodies. Next, the participation of the social component is to protect and

improve human health through the education of the general public on identifying contaminants of

concern in surface and groundwater resources, wastewater effluents and constituents from potential

pollutant sources, and recommendations to mitigate the pollution. Finally, the economic pillar involves

reducing the cost and amount of potable water used in industries of potential pollution sources when

treating and reusing their wastewater effluents.

First, we will evaluate and discuss Puerto Rico’s water quality standards assessment for rivers,

streams, lakes (reservoirs), and the San Juan Bay Estuary, by body size (miles), and attained category.

Next, identify contaminants of concern and indicator parameters for primary contact recreation,

secondary contact recreation, and raw source of drinking water designated uses. Categorize

contaminants of concern by the bulk of water quality, inorganic, organic, or metal constituents. Finally,

characterize pollutants in domestic wastewater plants and confined animal feeding operations.

3

2. Methods

2.1.0 Water Resources in Puerto Rico

It is fundamental to understand water resources in Puerto Rico to recognize the potential of

reusing wastewater. Approximately 88% of the water resources in Puerto Rico comes from surface

water, and the other 12% comes from groundwater (Water Use Data, 2015). In Puerto Rico, 60% of

domestic wastewater comes from septic tanks. These effluents are discharged directly into water

bodies. The other 40% of domestic wastewater comes from municipal discharges. A study by the

Departamento de Recursos Naturales y Ambientales (2005), determined that municipal discharges

generate approximately 223 million of gallons per day (MGD) of domestic wastewater, of which 149

MGD (67%) receive primary treatment, 63 MGD (28%) secondary, and 11 MGD (5%) tertiary. Domestic

wastewater treatment involves a combination of physical, chemical, and biological processes to remove

solids, organic matter, bacteria, and nutrients dissolved or suspended in its effluents (See 4.1.1,

Domestic Wastewater Treatment Plants). After treatment, these effluents are reintroduced to the ocean

(primary treatment), as well as streams, rivers, reservoirs, and estuaries (Inventario de Recursos,

2005). This vast quantity of water constitutes a significant resource with the potential for reuse for

diverse activities, including agricultural irrigation, and aquifer recharge.

2.1.1 Surface Water

Surface waters represent the most critical water resource in Puerto Rico. The physiography of

the Island includes 224 rivers and 553 streams, formed by the combined effects of climate and

geology (Morris et al., 2008). The abundance of rain over these water bodies contribute to a

significant water flow for most of the year (Fig.1). Even though there are no natural lakes in Puerto

Rico, there are 37 water reservoirs (dams). Water dams are the principal source of water for

consumption, industrial production, and agriculture operations (Morris et al., 2008).

4

Fig. 1 – Surface Water Resources – Image reproduce from the National Map Viewer website.

2.1.2 Groundwater

Puerto Rico has a diversity of geological formations that function as aquifers. These geological

formations are grouped into three types of fundamental geological formations: Alluvial deposits,

limestone (karst), and igneous rock (Fig. 2). An aquifer is a geological formation saturated with water.

An aquifer volume and permeability are plentiful to sustain the extraction of freshwater (Morris et al.,

2008). The North Coast Aquifers comprise an area of 2341 Km2 and consist of limestone rock (Karst)

and alluvial formations in river valleys (Morris et al., 2008). The alluvial aquifers in the floodplains are

composed of unconsolidated sand formations and permeable gravels deposited by ancient rivers. Thus,

alluvial aquifers have the highest groundwater recharge in Puerto Rico (Morris et al, 2008). The aquifers

in the inner valleys generally consist of alluvial deposits, fractured rock, and slight limestone (karst)

formations. These aquifers do not discharge into the sea. Therefore, they are not subject to saltwater

intrusion. However, the presence of iron and manganese have caused water quality deterioration in

some areas (Morris et al., 2008).

5

Fig. 2 – Groundwater Resources – Image reproduced from the US. Geological Survey website.

2.1.3 Water Uses

According to data collected by the United States Geological Survey (2015), Puerto Rico

extracted 577 million gallons per day (MGD) of fresh water to meet their social and economic needs.

Of this total, 510 MGD (88%) came from surface water and 67 MGD (12%) from groundwater resources

(Fig. 3a). Domestic supply is the primary freshwater consumer in Puerto Rico. It used 339 MGD (59%)

of freshwater, 338 MGD (66%) are allocated to surface waters (Fig. 3b) and approximately 1 MGD

(approximate 1%) to groundwater resources (Fig. 3c). The next top freshwater consumer is agriculture.

It utilized 218 MGD (38%) of freshwater, 161 MGD (32%) are allocated to surface water (Fig. 3b), and

57 MGD (85%) to groundwater resources (Fig. 3c). The least freshwater consumer is industrial use, it

extracted 20 MGD (3%) of the freshwater,11 MGD (2%) are allocated to surface water (Fig. 3b) and 9

MGD (14%) to groundwater resources (Fig. 3c) (Water Use Data, 2015).

6

Fig. 3a Fig. 3b Fig. 3c

Fig. 3a-c – Proportions of Water Use in Puerto Rico from Surface and Groundwater

2.2.0 Data Collection

Table 1 – Steps Descriptions

Steps Description

1

• Identify information resources to determine contaminants of concern in water bodies of Puerto Rico, which includes but not limited to:

o Puerto Rico Water Quality Assessment Report (2018).

o Puerto Rico Water Quality Standards Regulation (2019).

o Integrated Reporting Guidance under CWA Sections 303(d), 305(b), and 314(2019).

o NPDES Permit Writers' Manual (2010).

o Peer-review publications and scientific journal articles

2

• Evaluate and discuss Puerto Rico Water Quality Standards Assessment for rivers, streams, lakes (reservoirs), and the San Juan Bay Estuary by body size (miles) and attained category.

• Identify contaminants of concern and indicator parameters for primary contact recreation, secondary contact recreation, and raw source of drinking water designated uses.

o Contaminants of concern are chemical, biological, or radioactive materials found in effluents, sediments, or other substances generated by natural phenomena or human activities.

o Indicator parameters are focal contaminants of concern that are characteristic of water quality deterioration.

• Categorize contaminants of concern by:

o The Bulk of water quality

o Inorganic, organic, or metals constituents

3

• Identify the contaminants of concern and indicator parameters for domestic wastewater treatment plants and confined animal feeding operations.

• Categorize contaminants of concern by:

o The Bulk of water quality

o Inorganic, organic, or metals constituents

• Possible impacts on fauna, aquatic life, and humans

• Recommendations to mitigate water pollution

12%

88%

GROUNDWATER

SURFACE WATER

66%2%

32%

SURFACE WATER

DOMESTIC SUPPLY

INDUSTRIAL

AGRICULTURE

1%14%

85%

GROUNDWATER

DOMESTIC SUPPLY

INDUSTRIAL

AGRICULTURE

7

Table 2 – Water Bodies

Waterbody Type

River and Streams

Lakes (Reservoirs)

San Juan Bay Estuary

Table 3 – Pollution Source Groups

Source Group Source

Agriculture • Confined Animal Feeding Operations

Municipal Discharges/Sewage • Domestic Wastewater Treatment Plant

3. Results

3.1.0 Contaminants of Concern in Water Bodies

The Federal Clean Water Act (CWA) requires states and territories of the United States to

conduct a water quality assessment of water bodies every two years to ensure water quality standards

for primary contact recreation, secondary contact recreation, aquatic life, and raw source of drinking

water designated uses. This assessment determines whether water resources comply with water

quality standards for their designated use established by every state and territories of the United States.

For water bodies that do not meet water quality standards for the designated use, the law requires to

develop an indicator parameter (see Table 4, WQS Parameter Limits) for each contaminant of concern.

This requirement is known as the "303(d) list". According to the Puerto Rico Water Quality Standards

Regulation (2019), contaminants of concern are chemical, biological, or radioactive materials found in

effluents, sediments, or other substances generated by natural phenomena or human activities.

Indicator parameters are focal contaminants of concern that are characteristic of water quality

deterioration. Each indicator parameter reflected in the 303(d) list requires a Total Maximum Daily Load

(TMDL) permit according to the water body designated use. TMDL is the total maximum amount of

effluent allocated to a specific industry of potential pollutant sources without violating the water quality

standards established for its designated use (Puerto Rico Water Quality, 2019).

8

Table 4 – Water Quality Standards (WQS) Parameter Limits. The information portrayed in table 4 was gathered from the “Puerto Rico Water

Quality Standards Regulations” (2019). Pollutants Estuary Rivers, Streams, and Lakes

Bulk of Water Quality

Color Note 1 15-Pt-Co

Dissolved Exigen Not less than 5 mg/l Not less than 5 mg/l

Enteroccoci Note 9 Note 9

Fecal Coliform Note 10 Note 10

Other Pathogens - Free of Pathogens

pH 7.3-8.5 6.0-9.0

Taste and Odor Producing Substances Shall not be Present Shall not be Present

Temperature 32.2 °C 32.2 °C

Total Dissolved Solids - 500 mg/l

Turbidity 10 nephelometric turbidity units 50 nephelometric turbidity units

Inorganic Constituents

Chlorides - 250 mg/l

Chlorine 7.5 ug/l 11.0 ug/l

Cyanide (Free) 1.0 ug/l 5.2 ug/l

Fluroride - 4,000 ug/l

Selenium 71.14 ug/l 5.0 ug/l

Sulfates 2,800 mg/l 250 mg/l

Sulfide 2.0 ug/l 2.0 ug/l

Total Ammonia Nitrogen - Note 13

Total Nitrogen 5,000 ug/l Note 11

Total Phosphorus 1,000 ug/l Note 12

Organic Constituents

Surfactants (Methyle Chloride) 500 ug/l 100 ug/l

Metals Constituents

Aluminum - 87.0 ug/l

Antimony 640.0 ug/l 5.06 ug/l

Arsenic 36.0 ug/l 10.0 ug/l

Cadmium 8.85 ug/l Note 1

Chromium III - Note 2

Chromium VI 50.0 ug/l 11.0 ug/l

Copper 3.73 ug/l Note 3

Lead 8.52 ug/l Note 6

Mercury 0.051 ug/l 0.050 ug/l

Nickel 8.28 ug/l Note 4

Silver 2.24 ug/l Note 5

Thallium 0.47 ug/l 0.24 ug/l

Zinc 85.62 ug/l Note 7

9

Water Quality Standards Parameter Limits’ notes were gathered from the “Puerto Rico Water Quality

Standards Regulations” (2019).

Note 1 - Concentration in ug/l must not exceed the numerical value given by e(0.7409 [Ln Hardness] –4.719 )

Note 2 - Concentration in ug/l must not exceed the numerical value given by e(0.8190 [Ln Hardness] +0.6848)

Note 3 - Concentration in ug/l must not exceed the numerical value given by e(0.8545 [Ln Hardness] -1.702 )

Note 4 - Concentration in ug/l must not exceed the numerical value given by e(0.8460 [Ln Hardness]+ 0.0584 )

Note 5 - Concentration in ug/l must not exceed the numerical value given by e(1.72 [Ln Hardness] – 6.59 )

Note 6 - Concentration in ug/l must not exceed the numerical value given by e(1.273 [Ln Hardness] – 4.705 )

Note 7 - Concentration in ug/l must not exceed the numerical value given by e(0.8473 [Ln Hardness] + 0.884)

Note 8 – Shall not be altered, except by natural phenomena as defined under this regulation.

Note 9- The Enterococci density, in terms of geometric mean shall not exceed 35 colonies/100mL in any 90-day interval:

neither the 90th Percentile of the samples taken shall exceed 130 colonies/100mL in the same 90-day interval.

Note 10- In shellfish growing area or harvesting areas, designated by the pertinent agency and adopted by the Board,

through Resolution: the median fecal coliform concentration of a series representative samples of the water taken

sequentially, shall not exceed 14 Most Probable Number (MPN)/100mL, and not more than 10 percent of the samples shall

exceed 43 MPN/100mL.

Note 11- Shall not exceed 1,700 ug/L in any stream nor exceed 400 ug/L in any reservoir or lake.

Note 12 – Total Phosphorus shall not exceed 160 ug/L in any river and stream nor exceed 26 ug/L in any reservoir or lake.

Note 13 - Shall not exceed the concentration in mg/L calculated using the following equation:

𝑇𝐴𝑁=0.8876 × (0.02781+ 107.688−𝑝𝐻+ 1.19941+ 10𝑝𝐻−7.688) × (2.126 ×100.028 × (20−𝑇) Where: T = temperature in °C.

10

3.1.1 River and Streams

According to the Puerto Rico Impaired Waters List (2018), 5,036.6 miles of rivers and streams

were assessed for primary and secondary contact recreation and 5,052.8 miles for the raw source of

drinking water designated uses. For primary and secondary contact recreation, the data indicates that

75.9 miles (1%) of the water bodies assessed did not have enough information to determine if water

quality standards were impaired, 2,509.4 miles (50%) were impaired with a Total Maximum Daily Load

(TMDL) permit approved, and 2,451.3 miles (49%) were impaired without a TMDL completed. For raw

source of drinking water, the water quality evaluation suggests that 263.7 miles (5%) of rivers and

streams meet all the water quality standards, 2,182.5 miles (43%) did not have enough information to

determine if water quality standards were impaired, and 2,606.6 miles (52%) were impaired without a

TMDL completed. (Table 5). The data obtained from the assessment reveals that the leading water

quality impairments were due to enterococci, turbidity, total phosphorus, and total nitrogen (Table 6).

Table 5 – Water Quality Standards Assessment for Rivers and Streams. The information portrayed in table 5 was gathered from the

“Puerto Rico Impaired Waters List” (2018), which is found at the Environment Protection Agency website.

The water attainment categories are found at the Environmental Protection Agency website under “The Integrated Reporting Guidance CWA Sections 303(d), 305(b)” (2019). Category 1: Unimpaired or Restored Waters. Waters meets all designated uses. Category 2: Waters meets some designated uses. Category 3: Waters for which not enough data or information available to determine if water quality standards are impaired. Category 4:

4a – Water is impaired with an approved TMDL. 4b – Water is impaired without TMDL, and with appropriate 4b plan. 4c – Water is impaired due to pollution not caused by a pollutant (e.g., aquatic life use is not supported due to hydrologic alteration or habitat alteration).

Category 5: Water is impaired (or threatened) without a TMDL completed.

Primary and Secondary Contact Recreation Designated Use

Water Body Type Attained Category Total

Assessed 1 2 3 4a 4b 4c 5

River and Streams 0 0

75.9 miles

2,509.4 miles

0 0 2,451.3 miles

5,036.6 miles

Raw Source of Drinking Water Designated Use

Water Body Type Attained Category Total

Assessed 1 2 3 4a 4b 4c 5

River and Streams 263.7 miles

0 2,182.5 miles

0 0 0 2,606.6 miles

5,052.8 miles

11

Table 6 – River and Streams Contaminants of concern. The information portrayed in table 6 was gathered from the “Puerto Rico Impaired

Waters List” (2018), and “Puerto Rico Water Quality Standards Regulations” (2019), which are found at the Environment Protection Agency website.

Cause of Impairments Primary and Secondary

Contact Recreation Designated Use

Raw Source of Drinking Water Designated Use

Size of Water Impaired

(miles)

Bulk of Water Quality X- indicator Parameter*

pH X 208.4

Enterococci X X 2,451.3

Low Dissolved Oxygen X 1,064.9

Thermal Modifications X 33.8

Total Fecal Coliforms X 9.9

Turbidity X X 2,123.1

Inorganic Constituents

Ammonia X X 128.6

Free Cyanide 578.4

Total Nitrogen X X 1,269.3

Total Phosphorus X X 1,937.3

Organic Constituents

Pesticides X X 495.5

Surfactants (Methylene Chloride) X X 212.6

Metals Constituents

Arsenic X X 3.5

Cadmium X 54.7

Copper X 1,013.2

Lead X 434.6

Mercury X X 55.8

Silver 14.6 * See Table 4, WQS Parameter Limits

3.1.2 Lakes (reservoirs)

According to the Puerto Rico Impaired Waters List (2018), 136.1 miles of Lakes were assessed

for primary and secondary contact recreation, and raw source of drinking water designated uses. For

primary and secondary contact recreation, the data indicates that 136.1 miles (100%) of the water

bodies assessed were impaired with a Total Maximum Daily Load (TMDL) permit approved. For the

raw source of drinking water, the water quality evaluation suggests that 136.1 miles (100%) of the water

bodies assessed were impaired without a TMDL completed (Table 7). The data obtained from the

12

assessment reveals that the leading water quality impairments were due to low dissolved oxygen, total

phosphorus, pH, and pesticides. (Table 8).

Table 7 – Water Quality Standards Assessment for Lakes (reservoirs). The information portrayed in table 7 was gathered from the “Puerto

Rico Impaired Waters List” (2018), which is found at the Environment Protection Agency website.

The water attainment categories are found at the Environmental Protection Agency website under “The Integrated Reporting Guidance CWA Sections 303(d), 305(b)” (2019). Category 1: Unimpaired or Restored Waters. Waters meets all designated uses. Category 2: Waters meets some designated uses. Category 3: Waters for which not enough data or information available to determine if water quality standards are impaired. Category 4:

4a – Water is impaired with an approved TMDL. 4b – Water is impaired without TMDL, and with appropriate 4b plan. 4c – Water is impaired due to pollution not caused by a pollutant (e.g., aquatic life use is not supported due to hydrologic alteration or habitat alteration).

Category 5: Water is impaired (or threatened) without a TMDL completed.

Table 8 – Lakes (Reservoirs) Contaminants of concern. The information portrayed in table 8 was gathered from the “Puerto Rico Impaired

Waters List” (2018), and “Puerto Rico Water Quality Standards Regulations” (2019), which are found at the Environment Protection Agency website.

Cause of Impairments

Primary and Secondary Contact

Recreation Designated Use

Raw Source of Drinking Water Designated Use

Size of Water Impaired (miles)

Bulk of Water Quality X- indicator Parameter*

pH X 88.4

Low Dissolved Oxygen X 136.1

Turbidity X X 34.0

Inorganic Constituents

Total Nitrogen X X 26.8

Total Phosphorus X X 134.4

Organic Constituents

Pesticides X X 48.8

Surfactants (Methylene Chloride) X X 6.9

Metals Constituents

Arsenic X X 21.9

Copper X 25.9

Lead X 7.2 * See Table 4, WQS Parameter Limits

Primary and Secondary Contact Recreation Designated Use

Water Body Type Attained Category Total

Assessed 1 2 3 4a 4b 4c 5

Lakes (reservoirs) 0 0 0

136.1 miles

0 0

136.1 miles

Raw Source of Drinking Water Designated Use

Water Body Type Attained Category Total

Assessed 1 2 3 4a 4b 4c 5

Lakes (reservoirs) 0 0 0 0 0 0

136.1 miles

136.1 miles

13

3.1.3 San Juan Bay Estuary

According to the Puerto Rico Impaired Waters List (2018), 122.6 miles of the San Juan Bay

Estuary were assessed for primary and secondary contact recreation, and 55.9 miles for raw source of

drinking water designated use. For primary and secondary contact recreation, the data indicates that

122.6 miles (100%) of the water assessed were impaired without a Total Maximum Daily Load (TMDL)

completed. For the raw source of drinking water designated use, the water quality evaluation suggests

that 55.9 miles (100%) of the water assessed was impaired without a TMDL completed (Table 9). The

data obtained from the assessment reveals that the leading water quality impairments were due to pH,

enterococci, low dissolved oxygen, thermal modifications, turbidity, total phosphorus, total nitrogen,

ammonia, and oil and grease (Table 10).

Table 9 – Water Quality Standards Assessment for San Juan Bay Estuary. The information portrayed in table 9 was gathered from the

“Puerto Rico Impaired Waters List” (2018), which is found at the Environment Protection Agency website.

Primary and Secondary Contact Recreation Designated Use

Water Body Type Attained Category Total

Assessed 1 2 3 4a 4b 4c 5

San Juan Bay Estuary

0 0 0 0 0 0 122.6 miles

122.6 miles

Raw Source of Drinking Water Designated Use

Water Body Type Attained Category Total

Assessed 1 2 3 4a 4b 4c 5

San Juan Bay Estuary

0 0 0 0 0 0 55.9 miles

55.9 miles

The water attainment categories are found at the Environmental Protection Agency website under “The Integrated Reporting Guidance CWA Sections 303(d), 305(b)” (2019). Category 1: Unimpaired or Restored Waters. Waters meets all designated uses. Category 2: Waters meets some designated uses. Category 3: Waters for which not enough data or information available to determine if water quality standards are impaired. Category 4:

4a – Water is impaired with an approved TMDL. 4b – Water is impaired without TMDL, and with appropriate 4b plan. 4c – Water is impaired due to pollution not caused by a pollutant (e.g., aquatic life use is not supported due to hydrologic alteration or habitat alteration).

Category 5: Water is impaired (or threatened) without a TMDL completed.

14

Table 10 – San Juan Bay Estuary Contaminants of concern. The information portrayed in table 10 was gathered from the “Puerto Rico Impaired

Waters List” (2018), and “Puerto Rico Water Quality Standards Regulations” (2019), which are found at the Environment Protection Agency website.

Cause of Impairments Primary and Secondary

Contact Recreation Designated Use

Raw Source of Drinking Water Designated Use

Size of Water Impaired (miles)

Bulk of Water Quality X- indicator Parameter*

pH X 122.6

Enterococci X 122.6

Fecal Coliforms X 47.9

Low Dissolved Oxygen X 122.6

Thermal Modifications X 122.6

Turbidity X X 122.6

Inorganic Constituents

Ammonia X X 103.8

Selenium X 18.8

Total Nitrogen X X 103.8

Total Phosphorus X X 122.6

Organic Constituents

Oil and Grease X 122.6

Surfactants (Methylene Chloride) X X 66.7

Metals Constituents

Arsenic X X 18.8

Copper X 66.7

Lead X 66.7

Mercury X X 66.7 * See Table 4, WQS Parameter Limits

4. Discussion

Water quality deterioration is a direct consequence of physical, geochemical, and biological

forces that regulate the release, transport, and fate of a range of chemical substances. These

processes may be influenced by natural phenomena or human activities (Groundwater, 1990). After

evaluating the data obtained from the Puerto Rico Impaired Waters List (2018), the foremost common

causes of water quality deterioration in rivers, streams, lakes (reservoirs), and the San Juan Bay

Estuary are turbidity, total nitrogen, and total phosphorus. The excess of nutrients and turbidity that

affected the water quality standards in these water bodies can be attributed in part to the natural

phenomena Hurricane Maria. Heavy rains on the night of September 20, 2017, caused more than

15

40,000 landslides in the interior mountainous region of the island. One of the significant adverse

impacts of landslides is the transport of vast quantities of sediments to water bodies (Landslides, 2018).

According to the Puerto Rico Impaired Waters List (2018), another prime source of pollution was

domestic wastewater (onsite wastewater systems), impairing 5214.5 miles (20%) of rivers, streams,

lakes, and the San Juan Bay Estuary. The second leading source of pollution was confined animal

feeding operations (CAFO) impacting water quality standards in 3798.8 a mile (15%) of rivers, streams,

lakes, and the San Juan Bay Estuary (Table 11).

Table 11 – Potential Sources of Pollution. The information portrayed in table 11 was gathered from the “Puerto Rico Impaired Waters List”

(2018), which is found at the Environment Protection Agency website.

Potential Sources of Pollution

Rivers and

Streams Lakes

San Juan Bay Estuary

Total Miles

Size of Water Impaired (miles)

Agriculture 2613.5 90.2 - 2703.7

Collection System Failure 3029.6 36.4 122.6 3188.6

Confined Animal Feeding Operations 3609.2 67.0 122.6 3798.8

Industrial Discharges (Minor/Major) 2809.3 33.8 37.6 2880.7

Landfill 2037.7 15.0 55.9 2108.6

Marinas and Recreational Boating - - 18.8 18.8

Municipal Discharges (Minor/Major) 1752.0 12.7 18.8 1783.5

Onsite Wastewater Systems (Septic Tanks) 5011.7 136.1 66.7 5214.5

Package Plants 344.0 2.6 - 346.6

Surface Mining 615.8 - - 615.8

Unknown Source 4.8 - - 4.8

Urban Runoff/ Storm Sewers 3034.7 7.2 122.6 3164.5

4.1.0 Sources of Pollution

As defined in the Puerto Rico Water Quality Standards Regulations (2019), a source of pollution

is any activity, building, structure, facility, or vessel that generates, emits, unloads, stores, or transports

pollution. Pollution sources are classified as a point or non-point sources. A point source refers to any

visible, confined, and discrete transport from which pollutants are discharged. Effluents from point

sources include domestic wastewater treatment plants, industrial processes, and concentrated animal

feed operations and are regulated by a permit program called National Pollutant Discharge Elimination

16

System (NPDES Permit, 2016). Non-point sources of pollution are wastewater discharges from

stormwater runoff, cultivated crops, pastures, and forest lands. Most pollution problems are considered

non-point sources because they are difficult to identify, measure, manage, and control (NPDES Permit,

2016).

4.1.1 Domestic Wastewater Treatment Plants

The main objective of wastewater treatment plants is to accelerate the natural processes of

water purification by eliminating contaminants, pathogens, and chemicals (Table 12). Wastewater

treatment plants collect effluents from homes, businesses, and industries for treatment. Following

treatment, the water could be reintroduced to natural water systems, applied to the land, or reused

beneficially. As mentioned, domestic wastewater treatment includes a combination of physical,

chemical, and biological processes to remove solids, organic matter, bacteria, and nutrients dissolved

or suspended in its effluents (Inventario de Recursos, 2005).

After treatment, these effluents are discharged mainly to the ocean (primary treatment), as well

as streams, rivers, lakes (reservoirs), and estuaries. This volume of water constitutes a significant

resource with the potential reuse for diverse activities, including agricultural irrigation, and aquifer

recharge (Inventario de Recursos, 2005).

The primary treatment is the sediment filtration process. Secondary treatment processes can

eliminate up to 90% of the organic matter in the wastewater (Primer for Municipal, 2004). First, it goes

through nitrification by injecting oxygen and allowing microbes to decompose organic matter, producing

ammonium and nitrate as a byproduct. Then, it goes through an anaerobic process known as

denitrification to convert the nitrate into nitrogen gas. In the tertiary process, water is sent to the clarifiers

where the organic matter is separated. The organic matter is taken to the sludge stabilization area

where it is stabilized and converted to bio-solids that could go to land fields, agriculture land

applications, or incinerated (Primer for Municipal, 2004).

17

Finally, the water is filtered to remove any additional organic matter particles, then is chlorinated

and transferred to a storage tank to be tested and ensure that it meets all the water quality regulation

requirements. If not, the water will go through the whole process again. A significant challenge facing

wastewater treatment plants today is that the facilities are old and in need of modernization (Primer for

Municipal, 2004). Traditional wastewater treatment plants should be modernized to manage changes

in the flow and composition of wastewater better, reduce operating costs, and comply with the newer

and stricter regulatory standards on effluent discharge limits (Gernaey, K. V. et al., 2015).

A cost-effective method that could be implemented to mitigate pollution in water systems is

constructed wetlands. Constructed wetlands help reduce the excess nutrients and other contaminants

that reach water bodies. Wetlands are large basins that provide a sink for sediments and nutrients,

reduce the energy of flowing water, allowing time for various nutrient cycles to mitigate unwanted

pollutants. Constructed wetlands induce sedimentation of particulate P, making it available for plant

uptake. Wetlands are even more efficient at removing nitrogen. When nitrogen-enriched water enters

the wetland, anaerobic microorganisms use the nitrogen excess for respiration, reducing it to gas and

releasing it to the atmosphere (A Handbook, 1995).

Another approach for reducing nutrient pollution is proper nutrient management. Nutrient

management should include the “Four R’s”: apply the right nutrient, at the right rate, at the right time,

and in the right place for the chosen crop (Liu, Guodong, et al., 2018). Controlled-release fertilizers

(CRF) and slow-release fertilizers (SFR) are methods to reduce nutrient losses. Controlled-release

fertilizers are coated with inorganic or organic material, which controls the rate and duration of nutrient

release. These fertilizers are water-soluble and manufactured to meet a specific crop’s nutrient

requirements. Slow-release fertilizers include green manures, cover crops, and animal manures (Liu,

Guodong, et al., 2018).

18

Table 12 – Wastewater Treatment Plants Contaminants of Concern. The information portrayed in table 12 was gathered from “Literature

Review of Contaminants in Livestock and Poultry Manure and Implications for Water Quality” (2013) ,“Primer for Municipal Wastewater Treatment Systems” (2004), and “Puerto Rico Water Quality Standards Regulations” (2019), which are found at the Environment Protection Agency website.

Pollutants Primary and Secondary

Contact Indicator Parameter

Raw Source of Drinking Water Indicator Parameter

Potential Impacts

Bulk of Water Quality

pH X Can lead to a decrease in aquatic life

Enterococci X Fauna, aquatic, and human health effects

Low Dissolved Oxygen X Can lead to a decrease in aquatic life

Other Pathogens X X Fauna, aquatic, and human health effects

Thermal Modifications X Can lead to a decrease in aquatic life

Turbidity X X Suspended solids and cloudiness

Inorganic Constituents

Ammonia X X Aquatic life toxicity at elevated Concentrations

Bicarbonate Increase salinity in surface and groundwater

Carbonate Increase salinity in surface and groundwater

Cyanide X X Fauna, aquatic, and human health effects

Nitrate X Link to methemoglobinemia

Chlorine X Aquatic life toxicity at elevated Concentrations

Selenium X Aquatic life toxicity at elevated Concentrations

Sodium Increase salinity in surface and groundwater

Sulfate X Can lead to a decrease in aquatic life

Total Nitrogen X X Can lead to harmful algal blooms

Total Phosphorus X X Can lead to harmful algal blooms

Organic Constituents

Antimicrobials Increases antimicrobial resistance

Hormones Endocrine disruption in aquatic life

Oil and Grease X Water quality deterioration

Pesticides X X Potential endocrine disruption in aquatic life

Surfactants (Methylene Chloride)

X X Fauna, aquatic, and human health effects

Metals Constituents

Antimony X X Human health effects

Arsenic X X Aquatic life toxicity at elevated Concentrations

Cadmium X Aquatic life toxicity at elevated Concentrations

Chromium Aquatic life toxicity at elevated Concentrations

Copper X Aquatic life toxicity at elevated Concentrations

Lead X Aquatic life toxicity at elevated Concentrations

Mercury X X Human health effects

Nickel X Aquatic life toxicity at elevated Concentrations

Silver Aquatic life toxicity at elevated Concentrations

Thallium X X Human health effects

Zinc Aquatic life toxicity at elevated Concentrations

19

4.1.2 Confined Animal Feeding Operations

Confined animal feeding operations (CAFO) are agricultural operations where animals are kept,

raised, and fed in confined conditions. CAFO gather animals, feed, manure, and urine (Animal Feeding,

NRCS). Traditionally, manure was used as fertilizer applications to provide nutrients to cropland and,

as an amendment to improve soil quality. However, manure must be managed appropriately to avoid

adverse environmental impacts. CAFO effluents contain nutrients, pathogens, heavy metals,

antimicrobials, and hormones that can enter surface and groundwater (Literature Review, 2013), (Table

13).

The implementation of Best Management practices can help CAFO owners mitigate water

pollution and reuse water beneficially. Best Management Practices (BMP) are practices adapted by

farmers or urban communities to improve water quality standards (Puerto Rico Water Quality, 2019). A

Comprehensive Nutrient Management Plan (CNMP) is an essential aspect of agriculture BMPs that

could help CAFO operators comply with water quality regulations. A nutrient management plan

enhances efficiency and profitability in farm operations while preventing adverse environmental impacts

(Animal Feeding, NRCS).

Another effective method of handling animal manure is anaerobic digesters, such as covered

lagoons or fixed-film digesters. Digesters produce renewable energy and fertilizers while reducing

greenhouse gas emissions and water pollution. Also, these anaerobic biological methods can process

ten times more manure than aerobic methods, reducing odors, flies, and pathogens by 95 percent

(Manure Matters, 2006).

20

Table 13 – Confined Animal Feeding Operations Contaminants of Concern. The information portrayed in table 13 was gathered from

“Literature Review of Contaminants in Livestock and Poultry Manure and Implications for Water Quality” (2013) and “Puerto Rico Water Quality Standards Regulations” (2019), which are found at the Environment Protection Agency website.

Pollutants

Primary and Secondary Contact

Indicator Parameter

Raw Source of Drinking Water

Indicator Parameter

Potential Impacts

Bulk of Water Quality

Low Dissolved Oxygen X Can lead to a decrease in aquatic life

Pathogens X X Fauna, aquatic, and human health effects

Turbidity X X Suspended solids and cloudiness

Inorganic Constituents

Ammonia X X Aquatic life toxicity at elevated Concentrations

Bicarbonate Increase salinity in surface and groundwater

Carbonate Increase salinity in surface and groundwater

Chloride X Increase salinity in surface and groundwater

Nitrate X Link to methemoglobinemia

Selenium X Aquatic life toxicity at elevated Concentrations

Sodium Increase salinity in surface and groundwater

Sulfate X Can lead to a decrease in aquatic life

Total Nitrogen X X Can lead to harmful algal blooms

Total Phosphorus X X Can lead to harmful algal blooms

Organic Constituents

Antimicrobials Increases antimicrobial resistance

Hormones Endocrine disruption in aquatic life

Pesticides X X Potential endocrine disruption in aquatic life

Metals Constituents

Aluminum Aquatic life toxicity at elevated Concentrations

Arsenic X X Aquatic life toxicity at elevated Concentrations

Cadmium X Aquatic life toxicity at elevated Concentrations

Calcium Increase salinity in surface and groundwater

Copper X Aquatic life toxicity at elevated Concentrations

Iron Aquatic life toxicity at elevated Concentrations

Lead X Aquatic life toxicity at elevated Concentrations

Magnesium Increase salinity in surface and groundwater

Manganese Aquatic life toxicity at elevated Concentrations

Molybdenum Aquatic life toxicity at elevated Concentrations

Nickel X Aquatic life toxicity at elevated Concentrations

Potassium Increase salinity in surface and groundwater

Zinc Aquatic life toxicity at elevated Concentrations

21

5. Conclusion

In this research project, the identification of contaminants of concern and indicator parameters

for primary contact recreation, secondary contact recreation, and the raw source of drinking water

designated uses have been presented to provide an overview of impaired water bodies in Puerto Rico.

Domestic wastewater effluents contribute a substantial amount of pollution in surface and groundwater

resources in Puerto Rico. A significant challenge facing domestic wastewater treatment plants today is

that the facilities are old and need to be retrofitted. However, there are several cost-effective methods

and best management practices that could be implemented to mitigate pollution inputs in water bodies.

The information conveyed in this project could serve as an educational tool for students to learn

about different types of contaminants of concern found in wastewater effluents from the most common

point sources in Puerto Rico. Besides, this report could be considered a case study for water

conservation and planning in Puerto Rico by understanding the potential of reused water in industries

of possible sources of pollutants when treating and reusing their wastewater effluents.

There is a vast amount of data collected and analyzed on industries of potential sources of

pollution created by government agencies. Nevertheless, the general public does not benefit from this

information because the data is complicated and difficult to understand. The data compiled in this report

provides educational information to the general public in a concise and useful manner.

22

6. References

“A Handbook of Constructed Wetlands.” EPA, Environmental Protection Agency, 1995, https://www.epa.gov

“Animal Feeding Operations.” NRCS, Natural Resources Conservation Service, https://www.nrcs.usda.gov

Gernaey, K. V., et al. 12th International Symposium on Process Systems Engineering and 25th European Symposium on

Computer Aided Process Engineering. Vol. 37 (pp.1241-1246), Elsevier, 2015.

“Groundwater, Volume 1 Groundwater and Contamination Handbook.” EPA, Environmental Protection Agency, 1990.

https://nepis.epa.gov

“Integrated Reporting Guidance under CWA Sections 303(d), 305(b) and 314.” EPA, Environmental Protection Agency,

2019, https://www.epa.gov

“Inventario de Recursos de Agua de Puerto Rico,” Capítulo 8. DRNA, Departamento de Recursos Naturales y

Ambientales, 2005, http://drna.pr.gov

“Landslides Triggered by Hurricane Maria”, USGS, United States Geological Survey, 2018, https://www.usgs.gov.

“Literature Review of Contaminants in Livestock and Poultry Manure and Implications for Water Quality.” EPA,

Environmental Protection Agency, 2013. https://nepis.epa.gov

Liu, Guodong, et al. “Controlled-Release and Slow-Release Fertilizers as Nutrient Management Tools.” UF/IFAS,

University of Florida IFAS Extension, 2017, https://edis.ifas.ufl.edu

“Manure Matters”: UF Waste Management System Produces Energy, Protects Environment, and Stops Annoying

Odors. UF/IFAS, University of Florida, 2006, http://blogs.ifas.ufl.edu.

Morris, et al. “Plan Integral De Recursos De Agua De Puerto Rico,” Capitulo III. DRNA, Departamento de Recursos

Naturales y Ambientales, 2008, https://www.drna.pr.gov

“NPDES Application Form: 2A.” EPA, Environmental Protection Agency, 2019, https://www.epa.gov

“NPDES Permit Writers' Manual.” EPA, Environmental Protection Agency, 2010, https://www.epa.gov

“Primer for Municipal Wastewater Treatment Systems.” EPA, Environmental Protection Agency, 2004,

https://www.epa.gov.

“Puerto Rico 2018 Impaired Waters List.” EPA, Environmental Protection Agency, 2018, https://www.epa.gov

“Puerto Rico Water Quality Standards Regulations.” EPA, Environmental Protection Agency, 2019, https://www.epa.gov

“Sustainability Primer.” EPA, Environmental Protection Agency, 2019. https://www.epa.gov

“Water Use Data for Puerto Rico” USGS, United States Geological Survey, 2015, https://waterdata.usgs.gov.