Review of Chemical, Physical, and Toxicologic … and Miller, Inc., 2840 Plaza Place, Suite 350, Raleigh, NC 27612 ABSTRACT: Risk is a function of exposure and hazard, and both aspects

1

Copyright© 1996, CRC Press, Inc. — Files may be downloaded for personal use only. Reproduction of thismaterial without the consent of the publisher is prohibited.

Review of Chemical,Physical, and ToxicologicProperties of Componentsof Total Petroleum Hydrocarbons

Jenifer S. HeathWoodward-Clyde Consultants, 4582 S. Ulster, Suite 1000, Denver, Co 80237

Kristin Koblis, and Shawn L. SagerGeraghty and Miller, Inc., 2840 Plaza Place, Suite 350, Raleigh, NC 27612

ABSTRACT: Risk is a function of exposure and hazard, and both aspects must be incorporatedinto sound risk assessment efforts. However, risk assessment for sites contaminated with petro-leum products is complicated by a general lack of information relevant to exposure to andtoxicity of petroleum mixtures (especially total petroleum hydrocarbons, or TPH). Specifically,there is often inadequate information about the components of the TPH present at the site andthe physical and chemical properties and toxicities of these components. Such information iscrucial to developing a strong conceptual model of exposure to and risk from petroleumhydrocarbons at contaminated sites. This article presents information that can be incorporatedinto risk assessments for sites contaminated with petroleum hydrocarbons.

KEY WORDS: petroleum contamination, total petroleum hydrocarbons, risk assessment,toxicity, physical/chemical properties.

I. BACKGROUND

Environmental contamination by petroleum products is a significant concernthroughout the U.S. It is estimated that there are over 2 million undergroundstorage tanks subject to the federal underground storage tank regulations designedto minimize potential releases (Valentinetti, 1989). Not included in this figure areother sources of petroleum product contamination, such as heating oil tanks (whichare not subject to the regulations), refineries, aboveground tanks, terminals, pipe-lines, or accidental spills from other sources. An understanding of the risks asso-ciated with releases from these sources is crucial to effective decision makingabout both prevention and remediation of releases. However, as lamented byBauman of the American Petroleum Institute (1989), risk assessment efforts forpetroleum hydrocarbons in environmental media are frustrated significantly by thecomplex nature of petroleum products, the lack of adequate knowledge about themovement of petroleum components in soil, and the lack of knowledge about the

Journal of Soil Contamination, 2(1): (1993)

2


toxicity of these components. This article provides information that can be used todevelop a better understanding of the petroleum components present at sites, theirmovement in the environment, and their toxicity.

Once a release has occurred, environmental media at petroleum-contaminatedsites are typically sampled and analyzed for a handful of specific compounds (suchas benzene, toluene, ethylbenzene, xylenes (BTEX), and lead), and for totalpetroleum hydrocarbons (TPH). The BTEX components of petroleum products canbe identified and quantified, and their toxicity and mobility in the environment arerelatively well understood. However, although chemical analysis for TPH is rela-tively simple and inexpensive, this measure of petroleum components presentschallenges to risk assessors. For instance, the label “total” implies that analysis forTPH includes all petroleum hydrocarbons, which is far from true. Although severalmethods are available, each actually measures only a specific range of the hydro-carbon components (Bauman, 1991). Because petroleum product compositionvaries among sources and over time (as a result of weathering and environmentalfate and transport processes), the same concentration of TPH at two different sitesmay represent very different mixtures and, therefore, very different risks to humanhealth and the environment (Bauman, 1991; Millner et al., 1992).

Although the analytical approaches for TPH in the environment may satisfy theinformational needs of regulatory agencies and engineers designing remediationactivities, the level of detail (or lack thereof) presents significant challenges to riskassessors who must evaluate the movement of petroleum components in theenvironment, consider the inherent hazards associated with these chemicals (tox-icity), and estimate the risks these releases pose to human and ecological receptors.For instance, the polycyclic aromatic hydrocarbon content of diesel varies signifi-cantly across diesel products and could significantly affect the toxicity of the TPHmixtures present in the environment (Block et al., 1991). Risk assessors typicallyselect surrogate compounds (or combinations of compounds) to represent TPH sothat movement in the environment and toxicity can be evaluated manageably.

Three types of information contribute to selection of surrogate compounds forTPH: (1) the composition of TPH at the site, (2) information about the chemicaland physical properties of the TPH components, and (3) information quantifyingthe inherent toxicity of the components. This paper presents a compilation ofinformation about the composition of TPH from various sources, available chemi-cal and physical information about these components, and available toxicity infor-mation about them. This information can be applied to select surrogate compoundsfor TPH.

II. COMPONENTS OF TPH

Information about the composition of TPH from a variety of sources is summarizedin Tables 1 and 2. The considered petroleum product sources include gasoline,

3


TA

BLE

1C

ompo

sitio

n of

Gas

olin

e-B

ased

TP

H

Reg

ular

Pre

miu

mW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seG

asol

ine

unle

aded

gas

olin

eun

lead

ed g

asol

ine

Lead

ed g

asol

ine

regu

lar

lead

ed g

asol

ine

regu

lar

unle

aded

gas

olin

esu

per

unle

aded

gas

olin

eC

onst

ituen

tsw

eigh

t (%

)vo

lum

e (%

)vo

lum

e (%

)vo

lum

e (%

)(p

pb)

(ppb

)(p

pb)

Alc

ohol

s

2-B

utox

yeth

anol

16,8

00E

thyl

alc

ohol

<5

<5

Met

hyl a

lcoh

ol0.

20.

2t-

But

yl a

lcoh

ol22

,300

15,9

0093

3,00

0

Cyc

loal

kane

s

Cyc

lope

ntan

e0.

19–0

.58

1-tr

ans-

3-D

imet

hylc

yclo

hexa

ne0.

05–0

.12

1-ci

s-2-

Dim

ethy

lcyc

lope

ntan

e0.

07–0

.13

1-tr

ans-

2-D

imet

hylc

yclo

pent

ane

0.06

–0.2

0E

thyl

cycl

ohex

ane

0.17

–0.4

2E

thyl

cycl

open

tane

0.14

–0.2

11-

Met

hyl-c

is-2

-eth

ylcy

clop

enta

ne0.

06–0

.11

1-M

ethy

l-tra

ns-3

-Eth

ylcy

clop

enta

ne0.

06–0

.12

Isop

ropy

lcyc

lope

ntan

e0.

01–0

.02

n-P

ropy

lcyc

lope

ntan

e0.

01–0

.06

1,1,

2-T

rimet

hylc

yclo

pent

ane

0.06

–0.1

11-

tran

s-2-

cis-

3-T

rimet

hylc

yclo

pent

ane

0.01

–0.2

51-

tran

s-2-

cis-

4-T

rimet

hylc

yclo

pent

ane

0.03

–0.1

5

Cyc

loal

kene

s

Cyc

lohe

xene

0.03

Cyc

lope

nten

e0.

12–0

.18

5190

3-M

ethy

lcyc

lope

nten

e0.

03–0

.08

Chl

orin

ated

alip

hatic

s

Dib

rom

oeth

ane

190

mg/

l57

61,

2-D

ichl

oroe

than

e15

0–30

013

301,

1-D

ichl

oroe

than

e21

0 m

g/l

Eth

ylen

e di

brom

ide

0.7–

177.

2 m

g/kg

4


TA

BLE

1 (

cont

inue

d)C

ompo

sitio

n of

Gas

olin

e-B

ased

TP

H

Reg

ular

Pre

miu

mW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seG

asol

ine

unle

aded

gas

olin

eun

lead

ed g

asol

ine

Lead

ed g

asol

ine

regu

lar

lead

ed g

asol

ine

regu

lar

unle

aded

gas

olin

esu

per

unle

aded

gas

olin

eC

onst

ituen

tsw

eigh

t (%

)vo

lum

e (%

)vo

lum

e (%

)vo

lum

e (%

)(p

pb)

(ppb

)(p

pb)

Eth

yl a

lkan

es/a

lken

es

5-E

thyl

hept

ane

0.02

–0.1

63-

Eth

ylhe

xane

0.01

3-E

thyl

-2-p

ente

ne0.

03–0

.04

Eth

er

Met

hyl-t

-but

yl e

ther

<12

<12

43,7

0035

,100

966,

000

Met

hyl a

lkan

es

2,2-

Dim

ethy

lbut

ane

0.17

–0.8

42,

3-D

imet

hylb

utan

e0.

59–1

.55

2,4-

Dim

ethy

l-3-e

thyl

pent

ane

0.03

–0.0

72,

2-D

imet

hylh

epta

ne0.

01–0

.08

2,3-

Dim

ethy

lhep

tane

0.13

–0.5

12,

6-D

imet

hylh

epta

ne0.

07–0

.23

3,3-

Dim

ethy

lhep

tane

0.01

–0.0

83,

4-D

imet

hylh

epta

ne0.

07–0

.33

2,4-

Dim

ethy

lhex

ane

0.34

–0.8

22,

5-D

imet

hylh

exan

e0.

24–0

.52

3,4-

Dim

ethy

lhex

ane

0.16

–0.3

72,

6-D

imet

hylo

ctan

e0.

06–0

.12

2,3-

Dim

ethy

lpen

tane

0.32

–4.1

72,

4-D

imet

hylp

enta

ne0.

23–1

.71

3,3-

Dim

ethy

lpen

tane

0.02

–0.0

32-

Met

hyl-3

-eth

ylhe

xane

0.04

–0.1

39,

930

2-M

ethy

lbut

ane

2-M

ethy

lhep

tane

0.48

–1.0

53-

Met

hylh

epta

ne0.

63–1

.54

4-M

ethy

lhep

tane

0.22

–0.5

22-

Met

hylh

exan

e0.

36–1

.48

3-M

ethy

lhex

ane

0.3–

1.77

5


TA

BLE

1 (

cont

inue

d)C

ompo

sitio

n of

Gas

olin

e-B

ased

TP

H

Reg

ular

Pre

miu

mW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seG

asol

ine

unle

aded

gas

olin

eun

lead

ed g

asol

ine

Lead

ed g

asol

ine

regu

lar

lead

ed g

asol

ine

regu

lar

unle

aded

gas

olin

esu

per

unle

aded

gas

olin

eC

onst

ituen

tsw

eigh

t (%

)vo

lum

e (%

)vo

lum

e (%

)vo

lum

e (%

)(p

pb)

(ppb

)(p

pb)

2-M

ethy

lnon

ane

0.06

–0.4

13-

Met

hyln

onan

e0.

06–0

.32

4-M

ethy

lnon

ane

0.04

–0.2

62-

Met

hylo

ctan

e0.

14–0

.62

3-M

ethy

loct

ane

0.34

–0.8

54-

Met

hylo

ctan

e0.

11–0

.55

2-M

ethy

lpen

tane

2.91

–3.8

53-

Met

hylp

enta

ne2.

42,

2,3-

Trim

ethy

lbut

ane

0.01

–0.0

42,

2,4-

Trim

ethy

lhep

tane

0.12

–1.7

3,3,

5-T

rimet

hylh

epta

ne0.

02–0

.06

2,2,

4-T

rimet

hylh

exan

e0.

11–0

.18

2,2,

5-T

rimet

hylh

exan

e0.

17–5

.89

2,3,

3-T

rimet

hylh

exan

e0.

05–0

.12

2,3,

5-T

rimet

hylh

exan

e0.

05–1

.09

2,4,

4-T

rimet

hylh

exan

e0.

02–0

.16

2,2,

3-T

rimet

hylp

enta

ne0.

09–0

.23

2,2,

4-T

rimet

hylp

enta

ne0.

32–4

.58

2,3,

3-T

rimet

hylp

enta

ne0.

05–2

.28

2,3,

4-T

rimet

hylp

enta

ne0.

11–2

.8

Met

hyl a

lken

es

2,3-

Dim

ethy

l-1-b

uten

e0.

08–0

.12,

3-D

imet

hyl-1

-pen

tene

0.01

–0.0

22,

4-D

imet

hyl-1

-pen

tene

0.02

–0.0

34,

4-D

imet

hyl-1

-pen

tene

0.6

(vol

.)4,

4-D

imet

hyl-c

is-2

-pen

tene

0.02

2-M

ethy

l-1-b

uten

e0.

22–0

.66

2-M

ethy

l-2-b

uten

e0.

96–1

.28

2-M

ethy

l-1-p

ente

ne0.

2–0.

222-

Met

hyl-2

-pen

tene

0.27

–0.3

23-

Met

hyl-1

-but

ene

0.08

–0.1

20.

06–0

.08

0.06

–0.0

80.

06–0

.08

3-M

ethy

l-cis

-2-p

ente

ne0.

35–0

.45

3-M

ethy

l-tra

ns-2

-pen

tene

0.32

–0.4

44-

Met

hyl-c

is-2

-pen

tene

0.04

–0.0

54-

Met

hyl-t

rans

-2-p

ente

ne0.

08–0

.3

6


TA

BLE

1 (

cont

inue

d)C

ompo

sitio

n of

Gas

olin

e-B

ased

TP

H

Reg

ular

Pre

miu

mW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seG

asol

ine

unle

aded

gas

olin

eun

lead

ed g

asol

ine

Lead

ed g

asol

ine

regu

lar

lead

ed g

asol

ine

regu

lar

unle

aded

gas

olin

esu

per

unle

aded

gas

olin

eC

onst

ituen

tsw

eigh

t (%

)vo

lum

e (%

)vo

lum

e (%

)vo

lum

e (%

)(p

pb)

(ppb

)(p

pb)

Mon

ocyc

lic a

rom

atic

hyd

roca

rbon

s

Ben

zene

0.12

-3.5

2-5

2-5

2-5

30,5

0028

,100

67,0

00n-

But

ylbe

nzen

e0.

04-0

.44

0.08

0.08

0.2-

0.5

sec-

But

ylbe

nzen

e0.

01-0

.13

t-B

utyl

benz

ene

0.12

1,2-

Die

thyl

benz

ene

0.57

1,3-

Die

thyl

benz

ene

0.05

-0.3

81,

2-D

imet

hyl-3

-eth

ylbe

nzen

e0.

02-0

.19

1,2-

Dim

ethy

l-4-e

thyl

benz

ene

0.5-

0.73

1,3-

Dim

ethy

l-2-e

thyl

benz

ene

0.21

-0.5

91,

3-D

imet

hyl-4

-eth

ylbe

nzen

e0.

03-0

.44

1,3-

Dim

ethy

l-5-e

thyl

benz

ene

0.11

-0.4

21,

3-D

imet

hyl-5

-t-b

utyl

benz

ene

0.02

-0.1

61,

4-D

imet

hyl-2

-eth

ylbe

nzen

e0.

05-0

.36

Eth

ylbe

nzen

e0.

36–2

.86

55

54,

040

2,42

07,

400

Isob

utyl

benz

ene

0.01

–0.0

8Is

open

tylb

enze

ne0.

07–0

.17

eip -

Isop

ropy

lben

zene

<0.

01–0

.23

1-M

ethy

l-4-e

thyl

benz

ene

0.18

–11-

Met

hyl-2

-eth

ylbe

nzen

e0.

19–0

.56

1-M

ethy

l-3-e

thyl

benz

ene

0.31

–2.8

61-

Met

hyl-2

-n-p

ropy

lben

zene

0.01

–0.1

71-

Met

hyl-3

-n-p

ropy

lben

zene

0.08

–0.5

61-

Met

hyl-3

-isop

ropy

lben

zene

0.01

–0.1

21-

Met

hyl-3

-t-b

utyl

benz

ene

0.03

–0.1

11-

Met

hyl-4

-t-b

utyl

benz

ene

0.04

–0.1

3n -

Pen

tylb

enze

ne0.

01–0

.14

n-P

ropy

lben

zene

0.08

–0.7

20.

60.

61,

2,3,

4-T

etra

met

hylb

enze

ne0.

02–0

.19

1,2,

3,5-

Tet

ram

ethy

lben

zene

0.14

–1.0

61,

2,4,

5-T

etra

met

hylb

enze

ne0.

05–0

.67

Tol

uene

2.73

–21.

86–

76–

76–

731

,400

31,1

0010

7,40

01,

2,3-

Trim

ethy

lben

zene

0.21

–0.4

80.

730.

730.

731,

2,4-

Trim

ethy

lben

zene

0.66

–3.3

1,3,

5-T

rimet

hylb

enze

ne0.

13–1

.15

1.3

1.3

1.3

7


TA

BLE

1 (

cont

inue

d)C

ompo

sitio

n of

Gas

olin

e-B

ased

TP

H

Reg

ular

Pre

miu

mW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seG

asol

ine

unle

aded

gas

olin

eun

lead

ed g

asol

ine

Lead

ed g

asol

ine

regu

lar

lead

ed g

asol

ine

regu

lar

unle

aded

gas

olin

esu

per

unle

aded

gas

olin

eC

onst

ituen

tsw

eigh

t (%

)vo

lum

e (%

)vo

lum

e (%

)vo

lum

e (%

)(p

pb)

(ppb

)(p

pb)

o -X

ylen

e0.

68–2

.86

m-X

ylen

e1.

77–3

.87

13,9

0010

,900

11,5

00o,

p-X

ylen

es4,

840

5,66

0p-

Xyl

ene

0.77

–1.5

8X

ylen

es6–

76–

76–

7

Pol

ycyc

lic a

rom

atic

hyd

roca

rbon

s

Ant

hrac

ene

1.55

–1.8

4 m

g/l

1.55

–1.8

7 m

g/l

1.55

mg/

lB

enzo

[a]p

yren

e0.

19–2

.8 m

g/kg

Ben

zo[b

]flu

oran

then

e3.

9 m

g/l

3.9

mg/

l3.

9 m

g/l

Ben

zo[e

]pyr

ene

0.3

mg

0.3

mg

0.3

mg/

lF

luor

anth

ene

1.84

mg/

l1.

84 m

g/l

1.84

mg/

lN

apht

hale

ne0.

09–0

.49

0.2–

0.5

0.2–

0.5

0.08

Sim

ple

alka

nes

n-B

utan

e3.

93–4

.74–

54–

54–

5n-

Dec

ane

0.04

–0.5

n-D

odec

ane

0.04

–0.0

9n-

Hep

tane

0.31

–1.9

6n-

Hex

ane

0.24

–3.5

Isob

utan

e0.

12–0

.37

0.7–

10.

7–1

0.1

Isop

enta

ne6.

07–1

0.17

9–11

9–11

9–11

Neo

pent

ane

0.02

–0.0

5n-

Non

ane

0.07

–0.8

3n-

Oct

ane

0.36

–1.4

3n-

Pen

tane

5.73

–10.

922.

6–2.

72.

6–2.

72.

6–2.

7P

ropa

ne0.

01–0

.14

0.07

–0.0

80.

07–0

.08

0.07

–0.0

8n-

Und

ecan

e0.

05–0

.22

8


TA

BLE

1 (

cont

inue

d)C

ompo

sitio

n of

Gas

olin

e-B

ased

TP

H

Reg

ular

Pre

miu

mW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seW

ater

-sol

uble

-pha

seG

asol

ine

unle

aded

gas

olin

eun

lead

ed g

asol

ine

Lead

ed g

asol

ine

regu

lar

lead

ed g

asol

ine

regu

lar

unle

aded

gas

olin

esu

per

unle

aded

gas

olin

eC

onst

ituen

tsw

eigh

t (%

)vo

lum

e (%

)vo

lum

e (%

)vo

lum

e (%

)(p

pb)

(ppb

)(p

pb)

Sim

ple

alke

nes

2-B

uten

e0.

16–0

.17

0.16

–0.1

70.

16–0

.17

5,87

04,

740

8,79

0ci

s-2-

But

ene

0.13

–0.1

7tr

ans-

2-B

uten

e0.

16–0

.2ci

s-3-

Hep

tene

0.14

–0.1

7tr

ans -

3-H

epte

ne0.

06–0

.1ci

s-2-

Hex

ene

0.15

–0.2

4tr

ans-

2-H

exen

e0.

18–0

.36

cis-

3-H

exen

e0.

11–0

.13

tran

s -3-

Hex

ene

0.12

–0.1

51-

Pen

tene

0.33

–0.4

52-

Pen

tene

22,5

00ci

s-2-

Pen

tene

0.43

–0.6

7tr

ans-

2-P

ente

ne0.

52–0

.9

Unk

now

n

Inda

n0.

25–0

.34

1-M

ethy

linda

n0.

04–0

.17

2-M

ethy

linda

n0.

02–0

.14-

Met

hylin

dan

0.01

–0.1

65-

Met

hylin

dan

0.09

–0.3

Tet

ralin

0.01

–0.1

4T

ricre

syl p

hosp

hate

<0.

2<

0.2

Fro

m S

tate

of

Cal

iforn

ia,

Gui

delin

es f

or S

ite A

sses

smen

t, C

lean

up,

and

Und

ergr

ound

Sto

rage

Tan

k C

losu

re,

App

endi

x I,

1989

; W

atts

, G

roun

dwat

er M

onito

ring

Par

amet

ers

and

Pol

lutio

nS

ourc

es,

3rd

ed.,

Tab

les

7.3.

1 an

d 7.

3.2,

198

9; K

ram

er a

nd H

ayes

, N

.J.

Geo

l. S

urv.

Tec

h. M

emo.

, 87

, 87

, 19

87a.

9


TA

BLE

2C

ompo

sitio

n of

Die

sel-,

Jet

Fue

l A-,

Die

sel F

uel N

o. 2

-, a

nd F

uel O

il N

o. 2

-Bas

ed T

PH

Wat

er-s

olub

le-p

hase

Die

sel

Jet

fuel

AD

iese

l fue

l no.

2fu

el o

il no

. 2

Con

stitu

ents

(wt.

%)

(vol

. %

)(v

ol.

%)

(ppb

)

Cyc

loal

kane

s

Cyc

lope

ntan

e0.

59C

yclo

prop

ane,

1-m

ethy

l-2-(

3-m

ethy

lpen

tyl)

450

cis -

1,2-

Dim

ethy

lcyc

lohe

xane

460

Eth

ylcy

cloh

exan

e0.

0424

001-

Eth

yl-4

-met

hylc

yclo

hexa

ne19

00M

ethy

l cyc

lohe

xane

950

cis-

Oct

ahyd

rope

ntal

ene

250

Pro

pylc

yclo

hexa

ne0.

07T

etra

met

hylc

yclo

pent

ane

0.01

Trim

ethy

lcyc

lohe

xane

4800

1,1,

3-T

rimet

hylc

yclo

hexa

ne0.

03

Chl

orin

ated

alip

hatic

s

Dib

rom

oeth

ane

0.05

Eth

er

Met

hyl- t

-but

yl e

ther

117

Ket

one

Met

hyl i

sobu

tyl k

eton

e97

10


TA

BLE

2 (

cont

inue

d)C

ompo

sitio

n of

Die

sel-,

Jet

Fue

l A-,

Die

sel F

uel N

o. 2

-, a

nd F

uel O

il N

o. 2

-Bas

ed T

PH

Wat

er-s

olub

le-p

hase

Die

sel

Jet

fuel

AD

iese

l fue

l no.

2fu

el o

il no

. 2

Con

stitu

ents

(wt.

%)

(vol

. %

)(v

ol.

%)

(ppb

)

Met

hyl a

lkan

es

3,6-

Dim

ethy

l und

ecan

e59

06-

Eth

yl-2

-met

hyl d

ecan

e68

02-

Met

hylb

utan

e0.

2–0.

263-

Met

hyld

ecan

e0.

142-

Met

hyln

onan

e0.

24-

Met

hyln

onan

e0.

223-

Met

hylo

ctan

e2.

52-

Met

hyl-6

-pro

pyl d

odec

ane

510

2,6,

10-T

rimet

hyld

odec

ane

0.45

2,7,

10-T

rimet

hyld

odec

ane

510

2,3,

7-T

rimet

hyl o

ctan

e80

0

Met

hyl a

lken

es

3,3-

Dim

ethy

l-1-o

cten

e3,

100

Mon

ocyc

lic a

rom

atic

hyd

roca

rbon

s

Ben

zene

0.02

Tra

ce64

6B

enze

ne,

met

hyl (

1-m

ethy

leth

yl)

490–

4,40

0B

utyl

benz

ene

21,

2-D

ieth

ylbe

nzen

e0.

241,

2-D

imet

hyl-3

-pro

pylb

enze

ne5.

41,

4-D

imet

hyl-2

-eth

ylbe

nzen

e0.

2

11


TA

BLE

2 (

cont

inue

d)C

ompo

sitio

n of

Die

sel-,

Jet

Fue

l A-,

Die

sel F

uel N

o. 2

-, a

nd F

uel O

il N

o. 2

-Bas

ed T

PH

Wat

er-s

olub

le-p

hase

Die

sel

Jet

fuel

AD

iese

l fue

l no.

2fu

el o

il no

. 2

Con

stitu

ents

(wt.

%)

(vol

. %

)(v

ol.

%)

(ppb

)

Eth

ylbe

nzen

e0.

02T

race

1,36

01-

Eth

yl-3

-met

hyl b

enze

ne6,

200

1-M

ethy

leth

yl b

enze

ne12

,000

–20,

000

1-M

ethy

lpro

pyl b

enze

ne2,

200

1-M

ethy

l-4-p

ropy

lben

zene

3.3

Pro

pylb

enze

ne3–

52,

500

n-P

ropy

lben

zene

Tra

ce1,

2,4,

5-T

etra

met

hylb

enze

ne9

Tol

uene

Tra

ceT

race

1,68

01,

2,3-

Trim

ethy

lben

zene

6.6

1,3,

5-T

rimet

hylb

enze

neT

race

m-X

ylen

e3,

760

o,p-

Xyl

enes

3,77

0X

ylen

es0.

07T

race

Pol

ycyc

lic a

rom

atic

hyd

roca

rbon

s

Ant

hrac

ene

0.01

3–0.

02B

enzo

[a]p

yren

e0.

07 µ

g/kg

1,2-

Dim

ethy

lnap

htha

lene

540

1,3-

Dim

ethy

lnap

htha

lene

0.15

1-E

thyl

iden

e-1 H

-inde

ne72

0F

luor

ene

0.07

–0.1

175

Met

hyln

apht

hale

ne0.

57–0

.91

1-M

ethy

lnap

htha

lene

1,23

02-

Met

hyln

apht

hale

ne0.

34

12


TA

BLE

2 (

cont

inue

d)C

ompo

sitio

n of

Die

sel-,

Jet

Fue

l A-,

Die

sel F

uel N

o. 2

-, a

nd F

uel O

il N

o. 2

-Bas

ed T

PH

Wat

er-s

olub

le-p

hase

Die

sel

Jet

fuel

AD

iese

l fue

l no.

2fu

el o

il no

. 2

Con

stitu

ents

(wt.

%)

(vol

. %

)(v

ol.

%)

(ppb

)

Nap

htha

lene

0.13

0.14

0.14

–0.1

1P

hena

nthr

ene

0.26

–0.3

296

Pyr

ene

65

Sim

ple

alka

nes

Dec

ane

16.5

375

n-D

ecan

e0.

5–2

n-D

ocos

ane

<0.

2D

odec

ane

0.7

n-D

odec

ane

0.96

–11

n-E

icos

ane

0.23

–3n-

Hen

eico

sane

1n-

Hep

tade

cane

1.2–

6H

exad

ecan

e35

0n-

Hex

adec

ane

1.2–

6n-

Non

adec

ane

0.53

–4n-

Non

ane

0.1

n-O

ctad

ecan

e0.

82–5

Pen

tade

cane

1,17

0n-

Pen

tade

cane

1–7

7-P

ropy

l trid

ecan

e92

5n-

Tet

rade

cane

1.1–

9T

ridec

ane

0.5

1,03

0n -

Trid

ecan

e1.

1–10

Und

ecan

e36

590

n-U

ndec

ane

0.98

–9

13


TA

BLE

2 (

cont

inue

d)C

ompo

sitio

n of

Die

sel-,

Jet

Fue

l A-,

Die

sel F

uel N

o. 2

-, a

nd F

uel O

il N

o. 2

-Bas

ed T

PH

Wat

er-s

olub

le-p

hase

Die

sel

Jet

fuel

AD

iese

l fue

l no.

2fu

el o

il no

. 2

Con

stitu

ents

(wt.

%)

(vol

. %

)(v

ol.

%)

(ppb

)

Unk

now

n

Alk

yl n

itrat

e0.

2M

ethy

linda

ne0.

3P

enta

coza

ne1,

380

Fro

m S

tate

of

Cal

iforn

ia,

Gui

delin

es f

or S

ite A

sses

smen

t, C

lean

up,

and

Und

ergr

ound

Sto

rage

Tan

k C

losu

re,

App

endi

x I,

1989

; W

atts

, G

roun

dwat

er M

onito

ring

Par

amet

ers

and

Pol

lutio

n S

ourc

es,

3rd

ed.,

Tab

les

7.3.

1 an

d 7.

3.2,

1989

; K

ram

er a

nd H

ayes

, N

.J.

Geo

l. S

urv.

Tec

h. M

emo.

, 87

, 87

, 19

87b.

14


diesel, jet fuel, and water-soluble components of gasolines and fuel oil. Units ofquantification used in the table are the same as those provided in the originalsource.

Most of the these analyses were performed on fresh petroleum products. Envi-ronmental media are not expected to contain these same distributions of compo-nents due to volatilization following releases, biodegradation, selective migrationthrough soils and into ground water, and other processes. These processes must beconsidered when identifying surrogates for TPH at a particular site.

It is clear from Tables 1 and 2 that the composition of TPH varies significantly.For instance, gasoline products contain more straight-chain hydrocarbons than dodiesel products. This will affect both the movement of the products in the environ-ment and their toxicity. A greater number and variety of components have beenidentified in gasoline than in other petroleum products, suggesting complex char-acteristics affecting movement in the environment and toxicity, as well as a widerange of options for evaluating these characteristics.

The following sections provide available information on the components iden-tified in Tables 1 and 2. This information can be used to evaluate the effects ofweathering and movement in the environment on the composition of TPH atrelease sites and the toxicity of TPH.

III. CHEMICAL AND PHYSICAL PROPERTIES

Information about chemical and physical properties is presented in Table 3 for theTPH components identified in Tables 1 and 2. The following properties areincluded in the table: molecular weight, water solubility, specific gravity, vaporpressure, Henry’s law constant, diffusivity, organic carbon/water partition coeffi-cient (Koc), octanol/water partition coefficient (log Kow), fish bioconcentrationfactor (BCF), and surface-water half-life. The information was obtained fromreadily available sources and does not represent an exhaustive search of theliterature. Rather, it is adequate for appropriate identification of surrogates torepresent the weathering and movement of petroleum hydrocarbons in the environ-ment. The information also illustrates what is readily available in the open scien-tific literature.

Solubility is an important property affecting constituent migration in soils,ground water, and surface water. Solubility is expressed in terms of the number ofmilligrams of a constituent that can be dissolved in 1 l of water (mg/l) understandard conditions of 25°C and one atmosphere of pressure (atm). The higher thevalue of solubility, the greater the tendency of a constituent to dissolve in water.For inorganic constituents, solubility depends on the form of the constituents.

Volatility is another important property affecting the mobility and persistence oforganic constituents and several forms of inorganics. Henry’s law constant (H) isan indication of the tendency of a constituent to volatilize, or “partition,” from the

15


TA

BLE

3

Che

mic

al a

nd P

hysi

cal P

rope

rtie

s of

TP

H C

ompo

nent

s

Wat

erV

apor

Hen

ry’s

law

Sur

face

-wat

er

T1/

2 (d

ays)

Mol

ecul

arso

lubi

lity

Spe

cific

pres

sure

cons

tant

Diff

usiv

ityK

ocLo

gF

ish

BC

FC

onst

ituen

tsw

t.(m

g/L

25°C

)gr

avity

(mm

Hg

25°C

)(a

tm-m

3 /m

ol 2

5°C

)(c

m2 /

s)(m

l/g)

Kow

(L/k

g)Lo

w h

igh

Alc

ohol

s

Eth

yl a

lcoh

ol46

.07

280,

000

0.78

959

1.2E

– 0

50.

1236

80.

33.

10.

34M

ethy

l alc

ohol

3230

0 ,0

0013

02.

0E –

05

0.16

211

0.1

1.5

2.3

t-B

utyl

alc

ohol

74.1

0.78

842

0.09

752

0.37

Cyc

loal

kane

s

Cyc

lope

ntan

e70

.14

160

0.75

142

.41.

9E +

0.1

Met

hyl c

yclo

hexa

ne98

.19

140.

776.

184.

3E +

01

Cyc

loal

kene

s

Cyc

lohe

xene

84.1

655

(20

°C)

0.77

977

(20

°C)

Cyc

lope

nten

e68

.12

0.77

Chl

orin

ated

alip

hatic

s

1,2-

Dic

hlor

oeth

ane

997,

986–

8,65

01.

2387

1.3E

– 0

30.

0945

165

1.48

–2.1

35.

628

–180

Dib

rom

oeth

ane

187.

884.

31 (

30°C

)2,

701

17 (

30°C

)1,

1-D

ichl

oroe

than

e99

5060

1.17

5718

2.1

5.9E

– 0

30.

0959

30.2

1.79

Eth

er

Met

hyl- t

-but

yl e

ther

8848

000.

7425

05.

9E –

03

0.10

172

411.

21.

528

–180

Ket

one

Met

hyl i

sobu

tyl k

eton

e10

0.2

20,4

000.

8017

14.5

9.4E

– 0

50.

0758

819

–106

1.19

Met

hyl a

lkan

es

2,3-

Dim

ethy

lbut

ane

86.7

19.1

31.3

1.3E

+ 0

22,

3-D

imet

hylp

enta

ne10

0.21

5.25

9.18

1.8E

+ 0

22,

4-D

imet

hylp

enta

ne10

0.21

5.5

13.1

3.0E

+ 0

23,

3-D

imet

hylp

enta

ne10

0.21

5.94

111.

9E +

02

2-M

ethy

lhep

tane

114.

233–

Met

hylh

epta

ne11

4.23

0.79

22.

63.

8E +

02

4-M

ethy

lhep

tane

114.

23

16


TA

BLE

3 (

cont

inue

d)

Che

mic

al a

nd P

hysi

cal P

rope

rtie

s of

TP

H C

ompo

nent

s

Wat

erV

apor

Hen

ry’s

law

Sur

face

-wat

er

T1/

2 (d

ays)

Mol

ecul

arso

lubi

lity

Spe

cific

pres

sure

cons

tant

Diff

usiv

ityK

ocLo

gF

ish

BC

FC

onst

ituen

tsw

t.(m

g/L

25°C

)gr

avity

(mm

Hg

25°C

)(a

tm-m

3 /m

ol 2

5°C

)(c

m2 /

s)(m

l/g)

Kow

(L/k

g)Lo

w h

igh

2-M

ethy

lhex

ane

100.

212.

548.

783.

5E +

02

3-M

ethy

lhex

ane

100.

214.

958.

212.

4E +

02

4-M

ethy

loct

ane

128.

260.

115

0.90

31.

0E +

03

2-M

ethy

lpen

tane

86.1

713

0.65

428

.21.

7E +

02

3-M

ethy

lpen

tane

86.1

713

.10.

6645

25.3

1.7E

+ 0

22,

2,4-

Trim

ethy

lhex

ane

128.

262,

2,5-

Trim

ethy

lhex

ane

128.

261.

152.

213.

5E +

02

2,3,

3-T

rimet

hylh

exan

e12

8.26

2,3,

5-T

rimet

hylh

exan

e12

8.26

2,4,

4-tT

rimet

hylh

exan

e12

8.26

2,2,

3-T

rimet

hylp

enta

ne11

4.23

2,2,

4-T

rimet

hylp

enta

ne11

4.23

2.44

6.56

3.3E

+ 0

22,

3,3-

Trim

ethy

lpen

tane

114.

232,

3,4-

Trim

ethy

lpen

tane

114.

232.

33.

61.

9E +

02

Met

hyl a

lken

es

2-M

ethy

l-1-b

uten

e70

.14

0.65

2-M

ethy

l-2-b

uten

e70

.14

0.66

83-

Met

hyl-1

-but

ene

70.1

413

00.

648

120

5.5E

+ 0

12-

Met

hyl-1

-pen

tene

86.1

678

0.68

172-

Met

hyl-2

-pen

tene

86.1

63-

Met

hyl- c

is-2

-pen

tene

86.1

63-

Met

hyl- t

rans

-2-p

ente

ne86

.16

0.67

4-M

ethy

l-cis

-2-p

ente

ne86

.16

0.67

4-M

ethy

l- tra

ns-2

-pen

tene

86.1

6

Mon

ocyc

lic a

rom

atic

hyd

roca

rbon

s

Ben

zene

7817

800.

8895

5.5E

– 0

39.

30E

– 0

249

–100

1.56

–2.1

55.

25

But

ylbe

nzen

e13

40.

861

(23°

C)

1500

n-B

utyl

benz

ene

134

500.

861

(23°

C)

1.3E

+ 0

0se

c-B

utyl

benz

ene

134

30.9

0.87

1.5

(20°

C)

1.4E

+ 0

0t-

But

ylbe

nzen

e13

434

0.86

21.

1 (2

0°C

)1.

2E +

00

1,2-

Die

thyl

benz

ene

136

1500

1,3-

Die

thyl

benz

ene

136

1500

Eth

ylbe

nzen

e10

615

2–20

80.

879.

58.

7E –

03

6.70

E –

02

95–2

603.

05–3

.15

37.5

3Is

obut

ylbe

nzen

e13

4.2

10.1

0.24

83.

3E +

00

eip -

Isop

ropy

lben

zene

120

50 (

20°C

)0.

862

3.2

(20°

C)

1.0E

– 0

23.

662

n-P

enty

lben

zene

149

2520

17


TA

BLE

3 (

cont

inue

d)

Che

mic

al a

nd P

hysi

cal P

rope

rtie

s of

TP

H C

ompo

nent

s

Wat

erV

apor

Hen

ry’s

law

Sur

face

-wat

er

T1/

2 (d

ays)

Mol

ecul

arso

lubi

lity

Spe

cific

pres

sure

cons

tant

Diff

usiv

ityK

ocLo

gF

ish

BC

FC

onst

ituen

tsw

t.(m

g/L

25° C

)gr

avity

(mm

Hg

25° C

)(a

tm-m

3 /m

ol 2

5°C

)(c

m2 /

s)(m

l/g)

Kow

(L/k

g)Lo

w h

igh

Pro

pylb

enze

ne12

0.2

600.

449

7.0E

– 0

1n-

Pro

pylb

enze

ne12

060

(15

°C)

0.86

22.

5 (2

0°C

)5.

6E –

03

(15°

C)

3.57

–3.6

81,

2,3,

4-T

etra

met

hylb

enze

ne21

5.9

4.31

0.00

876

2.6E

– 0

115

001,

2,3,

5-T

etra

met

hylb

enze

ne21

5.9

3.5

0.01

865.

9E –

01

1500

1,2,

4,5-

Tet

ram

ethy

lben

zene

134.

23.

480.

0659

2.5E

+ 0

015

00T

olue

ne92

490–

627

0.87

286.

7E –

03

7.80

E –

02

115–

150

2.11

– 2.

810

.74

1,2,

3-T

rimet

hylb

enze

ne12

088

41,

2,4-

Trim

ethy

lben

zene

120

57 (

20°C

)0.

881.

43.

9E –

01

(20°

C)

1600

3.4

230

71,

3,5-

Trim

ethy

lben

zene

120

640.

865

1.4

3.7E

– 0

11.

60E

+ 0

33.

423

0m

-Xyl

ene

106

173

0.86

8410

6.3E

– 0

315

853.

2o-

Xyl

ene

106

204

0.87

596

105.

4E –

03

129

2.77

–3.1

6p-

Xyl

ene

106

200

0.85

665

106.

3E –

03

204

3.15

Xyl

enes

106

162—

200

0.87

6.6—

8.8

6.3E

– 0

37.

20E

– 0

212

8—1,

580

2.77

—3.

213

27

Pol

ycyc

lic a

rom

atic

hyd

roca

rbon

s

Ant

hrac

ene

178

0.03

0—1.

241.

7E –

5—

6.5E

– 0

55.

90E

– 0

216

,000

—4.

34—

4.54

300.

071

0.02

40.

1125

1.95

E –

426

,000

Ben

zo[a

]pyr

ene

252

0.00

38—

1.35

5.5E

– 0

9<

2.4E

– 6

4.70

E –

02

398,

000—

5.81

—6.

5030

0.01

50.

046

0.00

41,

900,

000

Ben

zo[b

]flu

oran

then

e25

20.

0012

. N

D5.

0E –

07

1.2E

– 0

54.

40E

– 0

255

0,00

06.

57N

D0.

36B

enzo

[e]p

yren

e25

24.

70E

– 0

21,

2-D

imet

hyln

apht

hale

ne15

842

301,

3-D

imet

hyln

apht

hale

ne15

842

30F

luor

anth

ene

202

0.20

6—1.

250.

0000

051.

7E –

02

42,0

005.

221.

150

0.87

52.

60.

373

Flu

oren

e16

61.

66—

1.98

1.2

1E –

3—

2.1E

– 0

45.

70E

– 0

250

004.

12—

4.38

3032

1E –

2M

ethy

lnap

htha

lene

142

271-

Met

hyln

apht

hale

ne14

228

1.02

5N

DN

DN

DN

DN

D12

9N

D2-

Met

hyln

apht

hale

ne14

225

1.00

10.

045

3.4E

– 0

46.

20E

– 0

27,

400—

3.86

—4.

1119

0N

D8,

500

Nap

htha

lene

128

30—

341.

162.

3E –

1—

4.6E

– 0

48.

20E

– 0

255

0—3.

2—4.

710

.50.

58.

7E –

13,

160

Phe

nant

hren

e17

80.

71—

1.29

1.18

0.00

068

2.6E

– 0

55.

40E

– 0

252

50—

4.2—

4.6

300.

125

1.04

38,9

00P

yren

e20

20.

013—

1.27

6.85

E –

07—

1.1E

– 0

55.

00E

– 0

246

,000

—4.

88—

5.32

300.

028

0.08

50.

171

2.5E

– 0

513

5,00

0

18


TA

BLE

3 (

cont

inue

d)

Che

mic

al a

nd P

hysi

cal P

rope

rtie

s of

TP

H C

ompo

nent

s

Wat

erV

apor

Hen

ry’s

law

Sur

face

-wat

er

T1/

2 (d

ays)

Mol

ecul

arso

lubi

lity

Spe

cific

pres

sure

cons

tant

Diff

usiv

ityK

ocLo

gF

ish

BC

FC

onst

ituen

tsw

t.(m

g/L

25°C

)gr

avity

(mm

Hg

25°C

)(a

tm-m

3 /m

ol 2

5°C

)(c

m2 /

s)(m

l/g)

Kow

(L/k

g)Lo

w h

igh

Sim

ple

alka

nes

n-B

utan

e58

.13

610.

61.

82E

+ 0

39.

6E –

01

Dec

ane

148.

280.

008

n-D

ecan

e14

8.28

0.05

20.

175

7.0E

+ 0

2D

odec

ane

170.

330.

0037

0.01

577.

5E +

02

n-D

odec

ane

170.

33n-

Eic

osan

e28

2.6

0.00

192.

67E

– 0

62.

9E –

01

n-H

epta

ne10

0.21

30.

0687

22.

3E +

02

n-H

exad

ecan

e22

6.44

0.00

628

0.00

0917

2.3E

+ 0

1n-

Hex

ane

8618

(20

°C)

0.66

1.2E

– 2

(20

°C)

7.7E

– 0

17.

50E

– 0

289

02.

77N

DN

DIs

obut

ane

58.1

348

.19

357

1.2E

+ 0

2Is

open

tane

72.1

548

92.6

1.4E

+ 0

2n-

Non

ane

128.

260.

070.

571

5.0E

+ 0

2n-

Oct

adec

ane

254.

40.

0021

2.50

E –

05

2.9E

+ 0

0n-

Oct

ane

114.

230.

661.

883.

0E +

02

n-P

enta

ne72

.15

3568

.41.

3E +

02

Pro

pane

44.0

963

0.58

8.5

n-T

etra

deca

ne19

0.38

0.00

696

0.00

127

1.1E

+ 0

2U

ndec

ane

156.

320.

044

0.05

221.

9E +

03

n-U

ndec

ane

156.

32

Sim

ple

alke

nes

2-B

uten

e21

0ci

s -2-

But

ene

56.1

0.64

tran

s-2-

But

ene

56.1

0.64

cis-

3-H

epte

ne98

9tr

ans-

3-H

epte

ne98

cis-

2-H

exen

e84

500.

86tr

ans-

2-H

exen

e84

500.

86ci

s-3-

Hex

ene

84tr

ans-

3-H

exen

e84

1-P

ente

ne70

.14

150

854.

0E +

01

2-P

ente

ne70

.14

203

662.

3E +

01

cis-

2-P

ente

ne70

.14

tran

s-2-

Pen

tene

70.1

4

Fro

m B

idle

man

, T

. F

. et

al.

(198

6);

Bud

avar

i, S

. (1

989)

; D

ixon

, D

. an

d E

. R

issm

ann

(198

5);

How

ard,

P.

H.

(198

9);

How

ard,

P.

H.

(199

0);

How

ard,

P.

H.

et a

l. (1

991)

; Ly

man

, W

. J.

et

al.

(198

2);

Mac

kay,

D.

etal

. (1

983)

; M

acka

y, D

. an

d W

. Y

. S

hiu

(198

1);

Mon

tgom

ery,

J.

H.

and

L. M

. W

elko

m (

1990

); S

hen,

T.

J. (

1982

); S

tren

ge a

nd P

eter

son

(198

9);

U.S

.EP

A (

1991

); V

ersc

huer

en,

K.

(198

3).

19


aqueous or water phase to the vapor phase and is dependent on the vaporpressure and solubility of the constituent. Organic constituents having Hvalues of 10–3 atm-m3/mol or greater tend to volatilize from water; those withH values <10–3 atm-m3/mol may volatilize from water, but other processessuch as adsorption to soil or sediment may be more important (Howard,1989). In evaluating volatilization from water used within the home, U.S.Environmental Protection Agency (EPA) guidance (1991) recommends in-cluding constituents with an H of >10–5 atm-m3/mol and a molecular weightof <200 g/mol.

The potential for a constituent to adsorb to soil and sediment particles affectsmigration through soil and aquifer materials as well as migration from surfacewater to sediments. The potential for adsorption usually is expressed in terms ofa partition coefficient, Kd. A Kd is the ratio of the concentration of adsorbedconstituent to the concentration of aqueous-phase constituent and, although aunitless quantity, typically it is reported in units of milliliters per gram (ml/g).Higher values of Kd indicate greater potential for the constituent to sorb to soil,sediment, and aquifer materials. This partition coefficient may be determinedempirically or estimated using constituent-specific and sediment- or soil-specificparameters. The parameters used to calculate Kd for organic constituents are theorganic carbon/water partition coefficient (Koc), which measures the selectiveaffinity for soil organic carbon vs. water, and the fraction of organic carbon (foc)in soil, because Kd is commonly expressed as the product of the Koc and foc (EPA,1989a).

The octanol/water partition coefficient (Kow) is a measure of the selectiveaffinity for n-octanol vs. water. The fish BCF is used as an indication of the abilityof a constituent to bioaccumulate in fish.

Persistence is the “lasting power” of constituents and is commonly expressed interms of half-lives (t1/2) for specific environmental media. A half-life is the timerequired for one half of the mass of a compound to be transformed into otherconstituents.

IV. TOXICITY VALUES

For purposes of quantitative risk assessment, the inherent toxicity of each chemicalmust be reduced to numerical values. A distinction is made between carcino-genic and noncarcinogenic effects. For potential carcinogens, the current regu-latory guidelines (EPA, 1989b) use an extremely conservative approach inwhich it is assumed that any level of exposure to a carcinogen could hypotheti-cally cause cancer. This is contrary to the traditional toxicological approach, inwhich finite thresholds are identified below which toxic effects are not ex-pected to occur. This traditional approach still is applied to noncarcinogenichealth effects.

20


Identification of constituents as known, probable, or possible humancarcinogens is based on an EPA weight-of-evidence classification schemein which chemicals are systematically evaluated for their ability to causecancer in mammalian species and conclusions are reached about the poten-tial to cause cancer in humans. The EPA classification scheme (EPA,1989b) contains six classes based on the weight of available evidence, asfollows:

A: known human carcinogen

B1: probable human carcinogen, limited evidence in humans

B2: probable human carcinogen, sufficient evidence in animals and inad-equate data in humans

C: possible human carcinogen, limited evidence in animals

D: inadequate evidence to classify

E: evidence of noncarcinogenicity.

Some constituents in class D may have the potential to cause cancer, but adequatedata are not currently available to change the classification.

The toxicity value used to describe the potency of a class A, B1, B2, or Ccarcinogen is the cancer slope factor (CSF). The slope factor is generated by theEPA through the use of a mathematical model that extrapolates from the high dosesin animal studies to the low doses characterizing human exposures. The CSFrepresents the 95% upper confidence limit on the slope of the dose-response curvegenerated by the model.

For many noncarcinogenic effects, protective mechanisms must be overcomebefore the effect is manifested. Therefore, a finite dose (threshold), below whichadverse effects will not occur, is believed to exist for noncarcinogens. For a givenconstituent, the dose that elicits no effect when evaluating the most sensitiveresponse (the adverse effect that occurs at the lowest dose) in the most sensitivespecies is combined with uncertainty factors (“safety” factors, “modifying” fac-tors) to establish an acceptable dose (toxicity value) for noncarcinogenic effects.Acceptable doses that are sanctioned by the EPA are called verified referencedoses (RfDs) for oral or inhalation exposure or reference concentrations (RfCs) forinhalation exposure.

Most federal and state regulatory agencies expect that slope factors, cancerclassifications, RfDs, and RfCs will be taken from the Integrated Risk Informa-tion System (IRIS, 1992) or, in the absence of IRIS data, the EPA Health EffectsAssessment Summary Tables (HEAST) (EPA, 1992). Potential alternatives in-clude in-depth review of the literature pertaining to toxicity of a particularconstituent, resulting in independent development of a toxicity value, or estima-

21


tion of toxicity based on structure-activity relationships. However, most agencieslack the time or resources to evaluate such efforts. Thus IRIS and HEAST are thepreferred sources of information. IRIS is an online data base containing up-to-date health risk and regulatory information provided by the EPA and containsonly toxicity values that have been verified by the RfD or Carcinogen RiskAssessment Verification Endeavor Workgroups. HEAST is a tabular presenta-tion, also prepared by the EPA, of interim RfDs and slope factors. HEAST isupdated periodically. Available toxicity information from IRIS and HEAST isprovided in Table 4.

Toxicity values were available for only a small number of the componentsidentified in Tables 1 and 2. Although significant additional information is avail-able in the literature for a number of the other components, many regulatoryagencies are reluctant to accept toxicity values derived on the basis of the literatureif confirmatory information is not available on either IRIS or HEAST. Therefore,from the perspective of real-world applications for most petroleum release sites,the information provided here is most pertinent to selection of surrogate com-pounds for TPH.

V. DISCUSSION

The composition of released petroleum products varies significantly, depending onthe source, weathering of the product over time, and differential movement of thecomponents in the environment. For most release sites, detailed information aboutthe composition of TPH will not be available. Information presented in Tables 1and 2 can be used to determine roughly what the initial composition of TPH in thereleased product might have been, thereby providing a starting point for evaluationof petroleum product releases. The next important step is to consider the effects ofweathering on the ultimate composition of TPH remaining in the environment asa result of the release. Information presented in Table 3 describing chemical andphysical properties of TPH components can contribute to evaluation of the effectsof weathering and to consideration of the impact of fate and transport processes onthe composition of TPH both close to and away from the original release point.Surrogate compounds can be selected to depict movement of TPH (or fractions ofTPH) in the environment. Information provided in Table 4 can be used to identifyone or more surrogate compounds to represent the toxicity of TPH associated witha particular release.

When properly integrated, the information presented in this article cancontribute to selection of surrogate compounds that represent the movement ofsite-specific TPH in the environment and the toxicity of TPH that reacheshuman and ecological receptors. This approach can contribute to meaningfuldecision making about regulation and remediation of petroleum releases to theenvironment.

22


TA

BLE

4R

efer

ence

Dos

es,

U.S

. E

PA

Can

cer

Cla

ssifi

catio

ns,

and

Can

cer

Slo

pe F

acto

rs f

or T

PH

Com

pone

nts

RfD

ia (m

g/kg

/d)

RfD

ob (

mg/

kg/d

)C

ance

rC

SF

oc

CS

Fid

Con

stitu

ents

subc

hron

icch

roni

csu

bchr

onic

chro

nic

clas

s(m

g/kg

/d)

A–1

(mg/

kg/d

)A–1

Alc

ohol

s

t-B

utyl

alc

ohol

NA

NA

1.0E

+ 0

01.

0E –

01

DN

CN

CM

ethy

l alc

ohol

NA

NA

5.0E

+ 0

05.

0E –

01

DN

CN

C

Cyc

loal

kane

s

Dib

rom

oeth

ane

NA

NA

NA

NA

B2

8.5E

+ 0

17.

7E –

01

1,1-

Dic

hlor

oeth

ane

5.0E

+ 0

05.

0E –

01

1.0E

+ 0

01.

0E –

01

B2

1.4E

– 0

1N

AE

thyl

ene

dibr

omid

eN

AN

A2.

0E –

01

2.0E

– 0

2C

8.4E

– 0

2N

A

Eth

er

Met

hyl- t

-but

yl e

ther

1.4E

+ 0

01.

4E –

01

NA

NA

DN

CN

C

Mon

ocyc

lic a

rom

atic

hyd

roca

rbon

s

Ben

zene

NA

NA

NA

NA

A2.

9E –

02

2.9E

– 0

2E

thyl

benz

ene

2.9E

– 0

12.

9E –

01

1.0E

+ 0

01.

0E –

01

DN

CN

Cei

p-Is

opro

pylb

enze

ne2.

6E –

02

2.6E

– 0

33.

0E –

02

4.0E

– 0

2D

NC

NC

Tol

uene

5.7E

– 0

11.

1E –

01

2.0E

+ 0

02.

0E –

01

DN

CN

CX

ylen

esN

AN

A4.

0E +

00

2.0E

+ 0

0D

NC

NC

23


TA

BLE

4 (

cont

inue

d)R

efer

ence

Dos

es,

U.S

. E

PA

Can

cer

Cla

ssifi

catio

ns,

and

Can

cer

Slo

pe F

acto

rs f

or T

PH

Com

pone

nts

RfD

ia (m

g/kg

/d)

RfD

ob (

mg/

kg/d

)C

ance

rC

SF

oc

CS

Fid

Con

stitu

ents

subc

hron

icch

roni

csu

bchr

onic

chro

nic

clas

s(m

g/kg

/d)

A–1

(mg/

kg/d

)A–1

Pol

ycyc

lic a

rom

atic

hyd

roca

rbon

s

Ant

hrac

ene

NA

NA

3.0E

+ 0

03.

0E –

01

DN

CN

CB

enzo

[a]p

yren

eN

AN

AN

AN

AB

27.

3E +

00

6.1E

+ 0

0F

luor

anth

ene

NA

NA

4.0E

– 0

14.

0E –

02

DN

CN

CF

luor

ene

NA

NA

4.0E

– 0

24.

0E –

02

DN

CN

CN

apht

hale

neN

AN

A4.

0E –

02

4.0E

– 0

2D

NC

NC

Pyr

ene

NA

NA

3.0E

– 0

13.

0E –

02

DN

CN

C

Sim

ple

alka

nes

n-H

exan

e5.

7E –

02

5.7E

– 0

26.

0E –

01

6.0E

– 0

2D

NC

NC

aR

fDi =

inha

latio

n re

fere

nce

dose

.b

RfD

o =

ora

l ref

eren

ce d

ose.

cC

SF

o =

ora

l can

cer

slop

e fa

ctor

.d

CS

Fi =

inha

latio

n ca

ncer

slo

pe f

acto

r.

Fro

m U

.S.

EP

A H

EA

ST

, 19

92,

and

IRIS

, 19

92.

24


REFERENCES

Bauman, B. 1984. Soils contaminated by motor fuels: research activities and perspective of theAmerican petroleum institute. In: Petroleum Contaminated Soils. Vol. 1. (Kostecki, P. T. andCalabrese, E. J., Eds.) Chelsea, MI, Lewis Publishers, 3–19.

Bauman, B. 1991. Research needs: motor fuel contaminated soils. In: Hydrocarbon ContaminatedSoils. Vol. 1. (Kostecki, P. T. and Calabrese, E. J., Eds.) Chelsea, MI, Lewis Publishers, 41–56.

Bidleman, T. F et al. 1986. Vapor-particle partitioning of semi-volatile organic compounds: estimatesfrom field collections. Environ. Sci. Technol. 10:1038.

Block, R. N., Allworth, N., and Bishop, M. 1991. Assessment of diesel contamination in soil. In:Hydrocarbon Contaminated Soils. Vol. 1. (Kostecki, P. T. and Calabrese, E. J., Eds.) Chelsea,MI, Lewis Publishers, 135–148.

Budavari, S., Ed. 1989. The Merck Index: An Encyclopedia of Chemicals, Drugs and Biologicals,11th ed. Rahway, NJ, Merck.

State of California. 1989. Leaking Underground Fuel Tank Field Manual: Guidelines for SiteAssessment, Cleanup, and Underground Storage Tank Closure. Leaking Underground FuelTank Task Force.

Dixon, D. and Rissmann, E. 1985. Physical-chemical properties and categorization of RCRA wastesaccording to volatility. EPA 450/3-85-007. Office of Air Quality Planning Standards, 128 DL6.

Howard, P. H. 1989. Handbook of Environmental Fate and Exposure Data for Organic Chemicals,Volume I: Large Production and Priority Contaminants. Chelsea, MI, Lewis Publishers.

Howard, P. H. 1990. Handbook of Environmental Fate and Exposure Data for Organic Chemicals,Volume II: Solvents. Chelsea, MI, Lewis Publishers.

Howard, P. H. et al. 1991. Handbook of Environmental Degradation Rates. Chelsea, MI, LewisPublishers.

Kramer, W. H. and Hayes, T. J. 1987a. Water-soluble phase of gasoline: results of a laboratorymixing experiment. N.J. Geol. Surv. Tech. Memo. 87:5.

Kramer, W. H. and Hayes, T. J. 1987b. Water-soluble phase of number 2 fuel oil: results of alaboratory mixing experiment. N.J. Geol. Surv. Tech. Memo. 87:4.

Lyman, W. J. et al. 1982. Handbook of Chemical Property Estimation Methods. New York, McGraw-Hill.

Mackay, D. and Shiu, W. Y. 1981. A critical review of Henry’s law constants for chemicals ofenvironmental interest. J. Phys. Chem. Ref. Data. 10:1175–1199.

Mackay, D. et al. 1983. Physical chemical properties of polychlorinated biphenyls. In: PhysicalBehavior of PCBs in the Great Lakes. Ann Arbor, MI, Ann Arbor Science.

Millner, G. C. et al. 1992. Human health-based soil cleanup guidelines for diesel fuel no. 2. J. SoilContam. 1:103–157.

Montgomery, J. H. and Welkom, L. M. 1990. Ground Water Chemicals Desk Reference. Chelsea,MI, Lewis Publishers.

Shen, T. H. 1982. Air quality assurance for land disposal of industrial waste. Environ. Manage.6:297–305.

Strenge, D. L. and Peterson, S. R. 1989. Chemical data bases for the multimedia environmentalpollutant assessment system (MEPAS): Version 1. Prepared for the U.S. Department of Energy,Assistant Secretary, Office of Environmental Audit. Richland, WA, Pacific Northwest Labora-tory.

U.S. EPA. 1989a. Transport and fate of contaminants in the subsurface. Seminar publication,Cincinatti, OH, Center for Environmental Research Information.

U.S. EPA. 1989b. Risk assessment guidance for Superfund, Volume I: Human health evaluationmanual. Interim Final. EPA 540/1-89-002. Washington, DC, Office of Emergency and Reme-dial Response.

25


U.S. EPA. 1991. Toxic substance spreadsheet. Water Quality Standards Unit, Region IV, Feb. 25(1991).

U.S. EPA. 1992. Health effects assessment summary tables. OERR 9200 6-303(92-1). Washington,DC, Office of Emergency and Remedial Response.

U.S. EPA. 1992. Integrated risk information system (IRIS). Cincinatti, OH, Office of Health andEnvironmental Assessment.

Valentinetti, R. A. 1989. Federal underground storage tank regulations and contaminated soils. In:Petroleum Contaminated Soils. Volume I. (Kostecki, P. T. and Calabrese, E. J., Eds.) Chelsea,MI, Lewis Publishers, 55–60.

Verschueren, K. 1983. Handbook of Environmental Data on Organic Chemicals, 2nd ed. New York,Van Nostrand Reinhold.

Watts, G. B. 1989. Groundwater Monitoring Parameters and Pollution Sources. 3rd ed. FloridaDepartment of Environmental Regulation, Bureau of Waste Cleanup.

Documents

Review of Chemical, Physical, and Toxicologic … and Miller, Inc., 2840 Plaza Place, Suite 350, Raleigh, NC 27612 ABSTRACT: Risk is a function of exposure and hazard, and both aspects