ENVIRONMENTAL CONTAMINANTS ENCYCLOPEDIA

FUEL OIL NUMBER 4 ENTRY

July 1, 1997

COMPILERS/EDITORS: 

ROY J. IRWIN, NATIONAL PARK SERVICE

WITH ASSISTANCE FROM COLORADO STATE UNIVERSITY

STUDENT ASSISTANT CONTAMINANTS SPECIALISTS:

MARK VAN MOUWERIK

LYNETTE STEVENS

MARION DUBLER SEESE

WENDY BASHAM

NATIONAL PARK SERVICE 

WATER RESOURCES DIVISIONS, WATER OPERATIONS BRANCH

1201 Oakridge Drive, Suite 250

FORT COLLINS, COLORADO 80525 
WARNING/DISCLAIMERS: 

Where specific products, books, or laboratories are

mentioned, no official U.S. government endorsement is

implied. 

Digital format users: No software was independently

developed for this project. Technical questions related

to software should be directed to the manufacturer of

whatever software is being used to read the files. Adobe

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product with a wide variety of software and hardware

(DOS, Windows, MAC, and UNIX). 

This document was put together by human beings, mostly by

compiling or summarizing what other human beings have

written. Therefore, it most likely contains some

mistakes and/or potential misinterpretations and should

be used primarily as a way to search quickly for basic

information and information sources. It should not be

viewed as an exhaustive, "last-word" source for critical

applications (such as those requiring legally defensible

information). For critical applications (such as

litigation applications), it is best to use this document

to find sources, and then to obtain the original

documents and/or talk to the authors before depending too

heavily on a particular piece of information.

Like a library or most large databases (such as EPA's

national STORET water quality database), this document

contains information of variable quality from very

diverse sources. In compiling this document, mistakes

were found in peer reviewed journal articles, as well as

in databases with relatively elaborate quality control

mechanisms [366,649,940]. A few of these were caught

and marked with a "[sic]" notation, but undoubtedly

others slipped through. The [sic] notation was inserted

by the editors to indicate information or spelling that

seemed wrong or misleading, but which was nevertheless

cited verbatim rather than arbitrarily changing what the

author said. Most likely additional transcription errors and typos

have been added in some of our efforts. Furthermore,

with such complex subject matter, it is not always easy

to determine what is correct and what is incorrect,

especially with the "experts" often disagreeing. It is

not uncommon in scientific research for two different

researchers to come up with different results which lead

them to different conclusions. In compiling the

Encyclopedia, the editors did not try to resolve such

conflicts, but rather simply reported it all.
It should be kept in mind that data comparability is a

major problem in environmental toxicology since

laboratory and field methods are constantly changing and

since there are so many different "standard methods"

published by EPA, other federal agencies, state agencies,

and various private groups. What some laboratory and

field investigators actually do for standard operating

practice is often a unique combination of various

standard protocols and impromptu "improvements." In

fact, the interagency task force on water methods

concluded that [1014]:

It is the exception rather than the rule that

water-quality monitoring data from different

programs or time periods can be compared on a

scientifically sound basis, and that...

No nationally accepted standard definitions exist

for water quality parameters. The different

organizations may collect data using identical or

standard methods, but identify them by different

names, or use the same names for data collected by

different methods [1014].

Differences in field and laboratory methods are also

major issues related to (the lack of) data comparability

from media other than water: soil, sediments, tissues,

and air. 

In spite of numerous problems and complexities, knowledge

is often power in decisions related to chemical

contamination. It is therefore often helpful to be aware

of a broad universe of conflicting results or conflicting

expert opinions rather than having a portion of this

information arbitrarily censored by someone else.

Frequently one wants to know of the existence of

information, even if one later decides not to use it for

a particular application. Many would like to see a high

percentage of the information available and decide for

themselves what to throw out, partly because they don't

want to seem uniformed or be caught by surprise by

potentially important information. They are in a better

position if they can say: "I knew about that data,

assessed it based on the following quality assurance

criteria, and decided not to use it for this

application." This is especially true for users near the

end of long decision processes, such as hazardous site

cleanups, lengthy ecological risk assessments, or complex

natural resource damage assessments.

For some categories, the editors found no information and

inserted the phrase "no information found." This does

not necessarily mean that no information exists; it
simply means that during our efforts, the editors found

none. For many topics, there is probably information

"out there" that is not in the Encyclopedia. The more

time that passes without encyclopedia updates (none are

planned at the moment), the more true this statement will

become. Still, the Encyclopedia is unique in that it

contains broad ecotoxicology information from more

sources than many other reference documents. No updates

of this document are currently planned. However, it is

hoped that most of the information in the encyclopedia

will be useful for some time to come even with out

updates, just as one can still find information in the

1972 EPA Blue Book [12] that does not seem well

summarized anywhere else. 

Although the editors of this document have done their

best in the limited time available to insure accuracy of

quotes or summaries as being "what the original author

said," the proposed interagency funding of a bigger

project with more elaborate peer review and quality

control steps never materialized. 

The bottom line: The editors hope users find this

document useful, but don't expect or depend on

perfection herein. Neither the U.S. Government nor

the National Park Service make any claims that this

document is free of mistakes.

The following is one chemical topic entry (one file among

118). Before utilizing this entry, the reader is

strongly encouraged to read the README file (in this

subdirectory) for an introduction, an explanation of how

to use this document in general, an explanation of how to

search for power key section headings, an explanation of

the organization of each entry, an information quality

discussion, a discussion of copyright issues, and a

listing of other entries (other topics) covered. 

See the separate file entitled REFERENC for the identity

of numbered references in brackets. 

HOW TO CITE THIS DOCUMENT: As mentioned above, for

critical applications it is better to obtain and cite the

original publication after first verifying various data

quality assurance concerns. For more routine

applications, this document may be cited as:

Irwin, R.J., M. VanMouwerik, L. Stevens, M.D.

Seese, and W. Basham. 1997. Environmental

Contaminants Encyclopedia. National Park Service,

Water Resources Division, Fort Collins, Colorado.

Distributed within the Federal Government as an

Electronic Document (Projected public availability

on the internet or NTIS: 1998).
Fuel Oil Number 4 (No 4 Fuel Oil, Fuel Oil No. 4, CAS number 68476-

31-3)

Brief Introduction:

Br.Class: General Introduction and Classification

Information:

Fuel oils are comprised of mixtures of petroleum

distillate hydrocarbons [363,499]. The various kinds of

fuel oils are obtained by distilling crude oil, and

removing the different fractions. Fuel oil no. 4 is a

heavier distillate fuel oil than no. 2, yet lighter than

no. 5 [641]. Fuel oil no. 4 is usually a 'light'

residual, but sometimes is, or contains, a heavy

distillate [747]. Fuel oil no. 4 can be prepared by

combining 40 percent no. 2 fuel oil with 60 percent no.

6 fuel oil. It may also be prepared as a high-boiling

distillate or light residual of crude oil [641].

Fuel oil numbers 4, 5, and 6 are commonly known as

"residual oils" since they are manufactured in whole or

in part from distillation residues from refinery

processing [747]. These three heavy fuel oils are also

known as gas oils and are composed of hydrocarbons

ranging from C19 to C25 [872]. Residual oils are complex

mixtures of relatively high molecular weight compounds

and are difficult to characterize in detail. Molecular

types include asphaltenes, polar aromatics, naphthalene

aromatics, aromatics, saturated hydrocarbons and

heteromolecules containing sulfur, oxygen, nitrogen, and

metals [747].

Fuel oil no. 4 is intended for use in atomizing type

burners that atomize oils of higher viscosity than

domestic burners can handle. The permissible viscosity

ranges of no. 4 fuel oil allow it to be pumped and

atomized at relatively low storage temperatures.

Therefore, in any weather (except extreme cold), it

requires no preheating for handling in these burners

[641].

Appreciable concentrations of polycyclic aromatic

hydrocarbons (PAHs) are present in residual fuels because

of the common practice of using both uncracked and

cracked residues in their manufacture [747]. Most

blending stocks of residual fuel oils are likely to

contain 5% or more of four- to six-ring condensed

aromatic hydrocarbons. The exact identities and

concentrations of various PAHs depend on the nature and

amount of the low viscosity blending stocks and the

proportions of virgin and cracked residues [747]. 
Oil-soluble compounds of calcium, cerium, iron, or

manganese may be added to residual fuel oils to improve

combustion [747]. Concentrations vary with fuel oil, but

typically range between 50 to 300 ppm weight of the

active material ingredient [747]. 

According to the US Coast Guard Emergency Response

Notification System (1993), fuel oil no. 4 was one of the

top most spilled petroleum hydrocarbon products in U.S.

waters, both by volume and the number of notifications

[635]. 

ATSDR lists Diesel Fuel No. 4 as a synonym [962], but

this product has a different CAS number and perhaps

different additiives. However, specifications for both

heating fuels and transportation fuels are at least

somewhat similar [747]. Therefore, the reader may gain

additional insight by reading the Diesel Oil #4 entry,

since there will be some overlap in characteristics with

Fuel Oil #4.

Br.Haz: General Hazard/Toxicity Summary:

Fuel oil no. 4 can be directly toxic to some forms of

aquatic life, can coat birds, and is of concern as a

potential source of PAHs, a potentially harmful class of

aromatic hydrocarbons (see PAHs entry). 

Chronic effects of some of the constituents in fuel 4

(such as naphthalenes) include changes in the liver and

kidney [766]. Due to their relative persistence and

potential for various chronic effects (like

carcinogenicity) PAHs (and particularly the alkyl PAHs)

can contribute to long-term (chronic) hazards of fuel 4

in contaminated soils, sediments, and groundwater (see

PAHs entry). 

Many of the PAHs found in this product (see Chem.Detail

section below) are more toxic in sunlight or other UV

source than elsewhere (see PAHs as a group entry).

One of the hazardous groups of compounds in fuel oils is

PAHs (see PAHs entry). PAHs may be translocated in

plants and may accumulate in plants grown in contaminated

soil [40]. Presumably this also occurs in sediments and

aquatic plants and therefore might impact herbivorous

species of fish and wildlife. Although some research

seems to indicate that interior portions of above-ground

vegetables do not accumulate high concentrations of PAHs,

plants do translocate PAHs from roots to other plant

parts, such as developing shoots [40]. Some plants can

evidently catabolize benzo(a)pyrene, but metabolic

pathways have not been clearly defined. This is an
important factor since when PAHs do degrade through

metabolism, they often break down into even more toxic,

carcinogenic, and mutagenic compounds [40]. Metabolic

transformations of PAHs into even more hazardous

chemicals could also happen through microbial degradation

of PAHs in soils or sediments. This provides an

additional example of a situation where human health

based standards are not protective of fish and wildlife,

since it casts doubt on the environmental safety margin

provided by EPA's human health-based soil guideline of

=<100 ppm carcinogenic PAHs.

However, in a series of soil and hydrocultures of

the higher plants, tobacco, rye, and radish, as

well as algae cultures of lower plants (Chlorella

vulgaris, Scenedesmus obligurus, and

Ankistrodesmus) /results indicate/ that certain

polycyclic aromatic hydrocarbons (PAHs) have

growth-promoting effects on plants. Further, the

degree of the promoting effect corresponded to the

oncogenic activity of the hydrocarbon. The six

polycyclic aromatic hydrocarbons found in plants

were tested one at a time or in combination.

Considerable growth-promotion was noted (near to

100% in some cases) with the effectiveness of

hydrocarbons ranked as follows: (1) Benzo(a)pyrene

(2) Benzo(a)anthracene (3) Indeno (1,2,3-cd)pyrene,

Benzo(b)fluoranthene (4) Fluoranthene (5)

Benzo(ghi)perylene. [Graf W, Nowak W; Arch Hyg Bakt

150: 513-28 (1968) as cited in Health & Welfare

Canada; Polycyclic Aromatic Hydrocarbons p.67

(1979) Report No. 80-EHD-50] [366].

See also: ATSDR toxicological profile on fuels oils in

general, including this product [962].

Br.Car: Brief Summary of Carcinogenicity/Cancer Information:

Certain components of fuel no. 4, such as PAHs, may be

carcinogenic to animals and humans. There is sufficient

evidence for the carcinogenicity in experimental animals

of residual (heavy) fuel oils and cracked residues

derived from the oil refining of crude oil [747].

Residual (heavy) fuel oils are possibly carcinogenic to

humans [747].

The debates on which PAHs, alkyl PAHs, and other

aromatics found in this product to classify as

carcinogens, and the details of exactly how to perform

both ecological and human risk assessments on the complex

mixtures of PAHs typically found at contaminated sites,

are likely to continue. There are some clearly wrong

ways to go about it, but defining clearly right ways is
more difficult. PAHs usually occur in complex mixtures

rather than alone. Perhaps the most unambiguous thing

that can be said about complex PAH mixtures is that such

mixtures are often carcinogenic and possibly phototoxic.

One way to approach site specific risk assessments would

be to collect the complex mixture of PAHs and other

lipophilic contaminants in a semipermeable membrane

device (SPMD, also known as a fat bag) [894,895,896],

retrieve the contaminant mixture from the SPMD, then test

the mixture for carcinogenicity, toxicity, and

phototoxicity (James Huckins, National Biological

Service, and Roy Irwin, National Park Service, personal

communication, 1996). 

See also: ATSDR toxicological profile on fuels oils in

general, including this product [962].

See also: PAHs as a group and Fuel Oil, General entries.

Br.Dev: Brief Summary of Developmental, Reproductive,

Endocrine, and Genotoxicity Information:

Some of the PAHs found in fuel oil are either AHH active

or endocrine disruptors [561].

The results are mixed, but some reproductive and

fetotoxic effects have been associated with a few of the

compounds found in fuel no. 5 [766] (see entries on

individual compounds for more details). 

See also: ATSDR toxicological profile on fuels oils in

general, including this product [962].

See Chem.Detail section for compounds in this product,

then see individual compound entries for summaries of

information on individual components of this mixture.

See also: PAHs as a group entry.

Br.Fate: Brief Summary of Key Bioconcentration, Fate,

Transport, Persistence, Pathway, and Chemical/Physical

Information:

Fuel oil number 4 is considered to be a intermediate

product, with an environmental fate similar to a mediumgrade crude oil [777]. As such, about 1/3 of a spilled

fuel no. 4 would be expected to evaporate within 24

hours. Fuel no. 4 has variable acute toxicity, depending

on the specific amount of light fraction [777]. Fuel no.

4 may penetrate substrate and persist. Impacts to

waterfowl and fur-bearing animals can be severe during a

spill of residual oil due to coating and ingestion [777].
Petroleum distillates in order of decreasing volatility

include [363]:

1. Petroleum ether or benzene

2. Gasoline

3. Naphtha

4. Mineral spirits

5. Kerosene

6. Fuel oils

7. Lubricating oils

8. Paraffin wax

9. Asphalt or tar.

See also: ATSDR toxicological profile on fuels oils in

general, including this product [962].

Synonyms/ Substance Identification:

Light residual fuel oil [747]

Residual fuel oil [560]

NOTE: Fuel oil numbers 5 and 6 are also referred to as

residual fuel oil.

ATSDR lists Diesel Fuel No. 4 as a synonym [962], but this

product has a different CAS number and perhaps different

additiives (see Diesel Oil #4 entry).

ATSDR lists heavy residual fuel oil, marine diesel fuel, and

residual fuel oil number 4 as synonyms [962], but other

references do not seem to agree [560,560]. 

Associated Chemicals or Topics (Includes Transformation

Products):

See also individual entries: 

Fuel Oil, General

Fuel Oil Number 2

Fuel Oil Number 6

Oil Spills

Petroleum, General

PAHs as a group

Naphthalene

C1-Naphthalene

C2-Naphthalene

C3-Naphthalene

C4-Naphthalene

Biphenyl 

Acenaphthylene

Acenaphthene

Fluorene

C1-Fluorene
C2-Fluorene

C3-Fluorene

Anthracene 

Phenanthrene

C1-Phenanthrene/anthracene

C2-Phenanthrene/anthracene

C3-Phenanthrene/anthracene

C4-Phenanthrene/anthracene

Dibenzothiophene

C1-Dibenzothiophene 

C2-Dibenzothiophene

C3-Dibenzothiophene

Fluoranthene

Pyrene

C1-Fluoranthene/pyrene

Benzo(a)anthracene

Chrysene

C1-Chrysene

C2-Chrysene

C3-Chrysene

C4-Chrysene

Benzo(b)fluoranthene

Benzo(k)fluoranthene

Benzo(e)pyrene

Benzo(a)pyrene

Perylene

Indeno(1,2,3-c,d)pyrene 

Dibenz(a,h)anthracene 

Benzo(g,h,i)perylene 

Site Assessment-Related Information Provided by Shineldecker

(Potential Site-Specific Contaminants that May be Associated

with a Property Based on Current or Historical Use of the

Property) [490]:

Raw Materials, Intermediate Products, Final Products, and

Waste Products Generated During Manufacture and Use:

& Benzene

& Creosote

& Ethyl benzene

& Polynuclear aromatic hydrocarbons

& Toluene

& Xylenes

Water Data Interpretation, Concentrations and Toxicity (All Water

Data Subsections Start with "W."):

W.Low (Water Concentrations Considered Low):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual
components of this mixture.

W.High (Water Concentrations Considered High):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

W.Typical (Water Concentrations Considered Typical):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

W.Concern Levels, Water Quality Criteria, LC50 Values, Water

Quality Standards, Screening Levels, Dose/Response Data, and

other Water Benchmarks:

W.General (General Water Quality Standards, Criteria, and

Benchmarks Related to Protection of Aquatic Biota in

General; Includes Water Concentrations Versus Mixed or

General Aquatic Biota):

 Information from OHM/TADS [499]:

Pollution hazard:

Water pollution:

Persistency: Loss of fuel oil after 40 hour in

bubbler apparatus - 2.% Evaporated, .005%

Dissolved.

 

Effect on water treatment process:

Will interfere with settling and floc formation.

May plug filters and exchange beds.

 

Water uses threatened:

Recreation, potable supply, fisheries, irrigation,

industrial

 

Industrial fouling potential:

Boiler water feed should be limited to 7 ppm or

less. Oil can result in poor heat transport,

blistering, overheating and foaming. In reused

cooling water, no oil is acceptable. Oil causes

tastes in food processing water and is especially

detrimental to cement and paper making operations.

W.Plants (Water Concentrations vs. Plants):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on
individual components of this mixture.

W.Invertebrates (Water Concentrations vs. Invertebrates):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

W.Fish (Water Concentrations vs. Fish):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

W.Wildlife (Water Concentrations vs. Wildlife or Domestic

Animals):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

W.Human (Drinking Water and Other Human Concern Levels):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

W.Misc. (Other Non-concentration Water Information):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Sediment Data Interpretation, Concentrations and Toxicity (All

Sediment Data Subsections Start with "Sed."):

Sed.Low (Sediment Concentrations Considered Low):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Sed.High (Sediment Concentrations Considered High):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual
components of this mixture.

Sed.Typical (Sediment Concentrations Considered Typical):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Sed.Concern Levels, Sediment Quality Criteria, LC50 Values,

Sediment Quality Standards, Screening Levels, Dose/Response

Data and Other Sediment Benchmarks:

Sed.General (General Sediment Quality Standards,

Criteria, and Benchmarks Related to Protection of Aquatic

Biota in General; Includes Sediment Concentrations Versus

Mixed or General Aquatic Biota):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Sed.Plants (Sediment Concentrations vs. Plants):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Sed.Invertebrates (Sediment Concentrations vs.

Invertebrates):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Sed.Fish (Sediment Concentrations vs. Fish):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Sed.Wildlife (Sediment Concentrations vs. Wildlife or

Domestic Animals):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Sed.Human (Sediment Concentrations vs. Human):
No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Sed.Misc. (Other Non-concentration Sediment Information):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Soil Data Interpretation, Concentrations and Toxicity (All Soil

Data Subsections Start with "Soil."):

Soil.Low (Soil Concentrations Considered Low):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Soil.High (Soil Concentrations Considered High):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Soil.Typical (Soil Concentrations Considered Typical):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Soil.Concern Levels, Soil Quality Criteria, LC50 Values, Soil

Quality Standards, Screening Levels, Dose/Response Data and

Other Soil Benchmarks:

Soil.General (General Soil Quality Standards, Criteria,

and Benchmarks Related to Protection of Soil-dwelling

Biota in General; Includes Soil Concentrations Versus

Mixed or General Soil-dwelling Biota):

In 1988, New Jersey started using a TPH

concentration of 100 ppm as a soil cleanup

guideline thought to ensure that concentrations in

ground water do not exceed drinking water

standards; 100 ppm is thought to be relatively

conservative and designed to identify potential

problems [347]. More recently, the New Jersey

standard was broken down by fuel type: if number 6
or 4 fuel oils, the guideline is 100 ppm; if number

2 fuel oil or diesel the guideline is 1,000 ppm

(Steve Tatar, New Jersey Leaking Underground

Storage Tank project, personal communication). The

latest New Jersey values are part of a proposed

cleanup standard (March 31, 1992, NJ

Administrative Code) for all soil values (not just

leaking underground tanks). Most New Jersey

officials seem to believe the TPH guidelines in NJ

are in dry weight, since soil values for other

parameters are, but they hadn't yet been able to

find the written confirmation as of this writing. 

Soil.Plants (Soil Concentrations vs. Plants):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture. See also:

Br.Haz section above.

Soil.Invertebrates (Soil Concentrations vs.

Invertebrates):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Soil.Wildlife (Soil Concentrations vs. Wildlife or

Domestic Animals):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Soil.Human (Soil Concentrations vs. Human):

No information found on this complex and variable

mixture. See Chem.Detail section for chemicals

found in this product, then look up information on

each hazardous compound. Some individual compounds

found in petroleum products have low-concentration

human health benchmarks for soil (see individual

entries).

Soil.Misc. (Other Non-concentration Soil Information):

As of 1996, several States were considering allowing

natural attenuation (the "do nothing and let nature clean

up the mess through bioremediation" option) to proceed

near leaking storage tanks in situations where drinking

water was not being impacted and where human rather than
environmental resources were the main resources in the

immediate area (Roy Irwin, National Park Service,

personal communication, 1996). 

Others would point out that fuel oil spills into soils

are not necessarily a trivial environmental threat

related to ecotoxicology (emphasis on living things other

than humans), due to the many hazardous compounds in this

product (see Chem.Detail section below).

No other information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Tissue and Food Concentrations (All Tissue Data Interpretation

Subsections Start with "Tis."):

Tis.Plants:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Plants:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

B) Body Burden Residues in Plants: Typical, Elevated, or

of Concern Related to the Well-being of the Organism

Itself:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Tis.Invertebrates:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Invertebrates:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

B) Concentrations or Doses of Concern in Food Items

Eaten by Invertebrates:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on
individual components of this mixture.

C) Body Burden Residues in Invertebrates: Typical,

Elevated, or of Concern Related to the Well-being of the

Organism Itself:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Tis.Fish:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Fish (Includes FDA Action Levels for

Fish and Similar Benchmark Levels From Other Countries):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

B) Concentrations or Doses of Concern in Food Items

Eaten by Fish:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

C) Body Burden Residues in Fish: Typical, Elevated, or of

Concern Related to the Well-being of the Organism Itself:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Tis.Wildlife: Terrestrial and Aquatic Wildlife, Domestic

Animals and all Birds Whether Aquatic or not:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Wildlife, Domestic Animals, or Birds:

No information found as yet. However, there is

information available on some of the compounds

found in this product (see individual PAH

sections).

B) Concentrations or Doses of Concern in Food Items

Eaten by Wildlife, Birds, or Domestic Animals (Includes

LD50 Values Which do not Fit Well into Other Categories,

Includes Oral Doses Administered in Laboratory

Experiments):
 Information from RTECS [365]:

LDLO/LCLO - Lowest published lethal dose/conc

rabbit

LDLO; Route: Skin; Dose: 5200 mg/kg; Reference:

Acute Toxicity Data. Journal of the American

College of Toxicology, Part B 1:139, 1990. 

LD50/LC50 - Lethal dose/conc 50% kill

rat

LD50; Route: Oral; Dose: 5300 mg/kg; Reference:

Acute Toxicity Data. Journal of the American

College of Toxicology, Part B 1:139, 1990. 

Irritation

Skin - standard draize test

Rabbit

route: Skin; Dose: 500 mg; Reaction: mild;

Reference:Acute Toxicity Data. Journal of the

American College of Toxicology, Part B 1:139, 1990.

C) Body Burden Residues in Wildlife, Birds, or Domestic

Animals: Typical, Elevated, or of Concern Related to the

Well-being of the Organism Itself:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

Tis.Human:

A) Typical Concentrations in Human Food Survey Items:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

B) Concentrations or Doses of Concern in Food Items

Eaten by Humans (Includes Allowable Tolerances in Human

Food, FDA, State and Standards of Other Countries):

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.

C) Body Burden Residues in Humans: Typical, Elevated, or

of Concern Related to the Well-being of Humans:

No information found; see Chem.Detail section for

compounds in this product, then see individual

compound entries for summaries of information on

individual components of this mixture.
Tis.Misc. (Other Tissue Information):

No information found; see Chem.Detail section for

compounds in this product, then see individual compound

entries for summaries of information on individual

components of this mixture.

Bio.Detail: Detailed Information on Bioconcentration,

Biomagnification, or Bioavailability:

No information found; see Chem.Detail section for compounds in

this product, then see individual compound entries for

summaries of information on individual components of this

mixture.

Interactions:

No information found; see Chem.Detail section for compounds in

this product, then see individual compound entries for

summaries of information on individual components of this

mixture.

Uses/Sources:

No information found; see Chem.Detail section for compounds in

this product, then see individual compound entries for

summaries of information on individual components of this

mixture.

Forms/Preparations/Formulations:

Fuel oil no. 4 can be prepared by combining 40 percent no. 2

fuel oil with 60 percent no. 6 fuel oil. It may also be prepared

as a high-boiling distillate or light residual of crude oil [641].

Chem.Detail: Detailed Information on Chemical/Physical

Properties:

Caution: Every individual petroleum product has a unique

"fingerprint," or distinct set of constituents most commonly

identified by a gas chromatograph analysis. Due to the

varying properties of the same general category of a petroleum

product (each source and stage of a No. 4 fuel oil has a

unique gas chromatograph "fingerprint"), careful assessment of

the toxicity, specific gravity, and other physical

characteristics of each individual oil must be taken into

consideration to determine the exact effects of the product on

the environment. Therefore, the below comments on No. 4 fuel

oils are to be considered as representative, but not absolute

values typical of every batch of the product with the same

name.

Since PAHs are important hazardous components of this product,
risk assessments should include analyses of PAHs and alkyl PAHs

utilizing the NOAA protocol expanded scan [828] or other rigorous

GC/MS/SIM methods.

The heavy fuel oils (fuels oils number 4,5, and 6) contain 15-

40% aromatics, dominated by alkyl phenanthrenes and naphthalenes

[872]. Since fuel oils 4 and 5 are commonly produced by blending

fuel oil 6 with lighter distillates. Therefore, most (probably

all) of the PAHs and alkyl PAHs listed below would be expected to

occur in Fuel 4, just as they are in fuel 5 (see the Fuel 5 entry

for details):

Naphthalene

C1-Naphthalene

C2-Naphthalene

C3-Naphthalene

C4-Naphthalene

Biphenyl 

Acenaphthylene

Acenaphthene

Fluorene

C1-Fluorene

C2-Fluorene

C3-Fluorene

Anthracene 

Phenanthrene

C1-Phenanthrene/anthracene

C2-Phenanthrene/anthracene

C3-Phenanthrene/anthracene

C4-Phenanthrene/anthracene

Dibenzothiophene

C1-Dibenzothiophene 

C2-Dibenzothiophene

C3-Dibenzothiophene

Fluoranthene

Pyrene

C1-Fluoranthene/pyrene

Benzo(a)anthracene

Chrysene

C1-Chrysene

C2-Chrysene

C3-Chrysene

C4-Chrysene

Benzo(b)fluoranthene

Benzo(k)fluoranthene

Benzo(e)pyrene

Benzo(a)pyrene

Perylene

Indeno(1,2,3-c,d)pyrene 

Dibenz(a,h)anthracene 

Benzo(g,h,i)perylene 

Log KOW [875]: 3.3 to 7.06
Henry's Law Constant [875]: 5.9E-05 to 7.4

Solubility in Water [875,962]: ~5 mg/L.

Odor [875]: like kerosene.

Physicochemical information from Environment Canada [560]: 

NOTE: In this section, for properties with more than one

value, each value came from its own source; in other words, if

API Gravity at 60 F was measured several times and several

different answers were obtained, all of the answers are

provided [560]:

 API GRAVITY (60/60 degrees F) [560]:

NOTE: Created by the American Petroleum Institute (API),

API gravity is an arbitrary scale expressing the gravity

or density of liquid petroleum products [637]. This

scale was created in order to compare the densities of

various oils. API gravity = (141.5/specific gravity

[60/60 degrees F]) - 131.5, where specific gravity [60/60

degrees F] is the oil density at 60 degrees F divided by

the density of water at 60 degrees F.

 24.9 to 23.5

 25.0 

 DENSITY (g/mL) [560]:

For temperatures of oil (T) between 0 and 30 C:

Density = 0.97871 - 0.000710 T 

NOTE: The densities of crude oils and oil products

are dependent on the temperature and degree of

weathering (i.e., as temperature goes down and/or

the fraction of weathered oil increases, density

increases). The following density values are at

"0% Weathering Volume" - in other words, fresh No.

4 fuel oil. 

 

 Temp( C) Density (at 0% Weathering Volume)

 0 0.969 to 0.980

 0 0.914 to 0.922

 0.938

 15 0.904 to 0.912

 0.903

 20 0.901 to 0.909

 0.925

 30 0.895 to 0.902

 HYDROCARBON GROUP [560]:
NOTE: The main constituents of oil are generally grouped into

several categories. Asphaltene content increases with

increasing weathering, as does wax content.

Hydrocarbon Group Analysis (Weight %):

 Asphaltenes 3.2

 Wax Content (Weight %):

 5.5

 METAL CONTENT [560]:

 

 Other Metals (ppm):

 Vanadium 35.0

 Nickel 7.72

 Chromium 44.1 ppb

 Cobalt 32.8 ppb

 Iron 0.226

 Manganese 14.1 ppb

 Zinc 0.263

 Copper 0.0345

 SOLUBILITY:

Aqueous Solubility (mg/L) [560]: The solubility of oil in

water can be determined by bringing to equilibrium a volume of

oil and water, and then analyzing the water phase. Oil's

aqueous solubility is expressed as the cumulative

concentration of the individually dissolved components.

Solubility is significantly reduced by weathering.

 20 C 

 Water 6.46

Solubility [498]: Fuel oil is insoluble (sic, actually

"relatively insoluble") in water (AAR, 1987).

NOTE on Solubility: No exact numbers can be given for

solubilities of fuel oil in water because the composition

of an oil varies from refinery to refinery. Generally,

hydrocarbons of a lower molecular weight are more soluble

than those of a higher molecular weight. Branching of

hydrocarbon isomers, as well as ring formation, also

tends to increase solubility. For two rings with the

same carbon number, an unsaturated ring is more soluble

in water than a saturated ring. The solubility of

hydrocarbons in sea water is less than in fresh water.

Also, an increase in temperature will greatly increase

the amount of hydrocarbons which dissolve in water.

Turbulence will also increase the rate of solubility

[641]. 
Additional Physicochemical information from Environment Canada 

[560]: 

NOTE: In this section, for properties with more than one

value, each value came from its own source; in other words, if

API Gravity at 60 F was measured several times and several

different answers were obtained, all of the answers are

provided [560]:

 VISCOSITY

NOTE: Viscosity is a measure of the internal friction or the

resistivity to flow of a liquid [637]. The viscosities of

crude oils and oil products are dependent on the temperature

and degree of weathering (as temperature goes down and/or the

fraction of weathered oil increases, viscosity increases).

The following viscosity values are at "0% Weathering Volume" -

in other words, fresh No. 4 fuel oil. 

Dynamic Viscosity (mPa.s or cP):

Temp( C) Dynamic Viscosity (at 0% Weathering Volume) 

 10 47.2

 20 22.7

Kinematic Viscosity (mm2/sec or cSt):

Temp( C) Kinematic Viscosity (at 0% Weathering Volume) 

 10 40 to 101

 15 33 to 79

 20 27 to 60

 30 18 to 38

 38 5.8 to 26.4

 2.0 to 5.8 for No.4 Light

 40 11 to 26

 Note: Data obtained from a graph (Curl 77)

Pour Point (degrees C): 

Pour point is the lowest temperature at which an oil sample is

observed to flow when cooled under prescribed conditions. It

is affected by weathering (the larger the fraction of oil

weathered, the higher the pour point).

 -29 to -9

 max -6

 -7

 5

 INTERFACIAL TENSIONS 

NOTE: Interfacial tension is the force of attraction between

molecules at the interface of a liquid. These tensions are
essential for calculating the spreading rates and the likely

extent to which the oil will form oil-in-water and water-inoil emulsions. The interfacial tensions of crude oils and oil

products are dependent on the temperature and degree of

weathering. The following tension values are at "0%

Weathering Volume" - in other words, fresh No. 4 fuel oil. 

Air-Oil (mN/M or dynes/cm): 

Temp( C) Air-Oil Tension (at 0% Weathering Volume) 

 20 32.1

Oil-Seawater (mN/M or dynes/cm):

Temp( C) Oil-Seawater Tension (at 0% Weathering Volume) 

 20 30.23

 EMULSION 

NOTE: An emulsion is a suspension of small globules of one

liquid in a second liquid with which the first will not mix

[492]. Hence, water-in-oil emulsions are stable emulsions of

small droplets of water incorporated in oil. Termed

"chocolate mousse," these stable water-in-oil emulsions can

have different characteristics than the parent crude oil.

Emulsion characteristics of crude oils and oil products are

dependent on the temperature and degree of weathering. The

following typical values are at "0% Weathering Volume" - in

other words, fresh No. 4 fuel oil. 

Emulsion Stability:

 Forms stable emulsion (Curl 77)

 FIRE AND REACTIVITY 

NOTE: Flash point is the lowest temperature at which vapors

arising from the oil will ignite momentarily (flash) on

application of a flame under specific conditions [637].

Flash Point (degrees C):

 54

 78

 min 55

 min 38 for No.4 Light

 > 54 (closed cup)

Auto Ignition Temperature (degrees C):

 263

Flammability Limits (Volume %):

 in air: 1.0 to 5.0

 DISTILLATION 
NOTE: Distillation data provides an indication of an oil's

volatility and relative component distribution. Distillation

data is reported as volume % recovered. 

Distillation (degrees C):

(Vol%) Liquid Temp

 IBP 245

 5 257

 10 269

 15 281

 20 293

 25 305

 30 317

 NOTE: IBP = initial boiling point

 Boiling Range (degrees C): 

 101 to > 588

 SENSATION

 

 Color 

 Brown 

 OTHER 

Reid method Vapor Pressure (kPa):

Temp( C) Pressure 

 37.8 0.689 (estimated)

Information from Hazard Management Data Base [498]:

REACTIVITY

When heated to decomposition, fuel oils emit acrid smoke and

irritating fumes (Sax & Lewis, 1989).

Fuel oils can react vigorously with oxidizing materials (Sax

& Lewis, 1989).

 Information from OHM/TADS [499]:

FIRE/EXPLOSION/CORROSION HAZARDS

Flammability: MODERATE. COMBUSTION WITH HEATING MODERATE

HAZARD

Standard codes: NFPA - -,2,0

Toxic combustion products: NO GREAT HAZARD

Flash point (degrees C): 66

Autoignition temperature (degrees C): 408

Fate.Detail: Detailed Information on Fate, Transport,
Persistence, and/or Pathways:

No information found; see Chem.Detail section for compounds in

this product, then see individual compound entries for

summaries of information on individual components of this

mixture.

Laboratory and/or Field Analyses:

As mentioned in the Brief Introduction, fuel oil No. 4 may

contain PAHs. PAHs are of concern in Fuel Oils in general [962]

Appreciable concentrations of PAHs are present in residual fuels

because on the common practice of using both uncracked and cracked

residues in their manufacture [747]. See also: PAHs as a group and

Fuel Oil, General entries. 

Recent (1991) studies have indicated that EPA approved methods

used for oil spill assessments (including total petroleum

hydrocarbons method 418.1, semivolatile priority pollutant organics

methods 625 and 8270, and volatile organic priority pollutant

methods 602, 1624, and 8240) are all inadequate for generating

scientifically defensible information for Natural Resource Damage

Assessments [468]. These general organic chemical methods are

deficient in chemical selectivity (types of constituents analyzed)

and sensitivity (detection limits); the deficiencies in these two

areas lead to an inability to interpret the environmental

significance of the data in a scientifically defensible manner

[468]. 

Due to the presence of light aromatics and PAHs in fuel oils,

we recommend the following decision tree: 

Decision Tree (dichotomous key) for selection of lab methods

for measuring contamination from midrange fuel oils:

1a. Your main concern is biological effects of petroleum

products....................................................2

1b. Your main concern is cleanup or remediation 

but no ecological or human resources are at risk............3

2a. The resource at risk is primarily humans via a drinking water

pathway, either the contamination of groundwater used for

drinking water, or the fresh* or continuing contamination of

surface waters used as drinking water, or the risk is

primarily to aquatic species in confined** surface waters from

a fresh* spill, or the risk is to surface waters re-emerging

from contaminated groundwater resources whether the spill is

fresh* or not; the medium and/or pathway of concern is water

rather than sediments, soil, or tissues. Note: although heavy

products have a lower percentage of BTEX and other relatively

soluble compounds which typically threaten drinking water,

ground water, or water column organisms, some heavy oils

including crudes do contain some of these water soluble

compounds, so they cannot be ignored........................4
2b. The resource at risk is something else......................5

3a. The spilled substance is a fresh* oil product of known

composition: If required to do so by a regulatory authority,

perform whichever Total Petroleum Hydrocarbon (TPH) analysis

specified by the regulator. However, keep in mind that due to

its numerous limitations, the use of the common EPA method

418.1 for Total Petroleum Hydrocarbons is not recommended as

a stand-alone method unless the results can first be

consistently correlated (over time, as the oil ages) with the

better NOAA protocol expanded scan*** for polycyclic aromatic

hydrocarbons (PAHs) and alkyl PAHs. If not required to

perform an EPA method 418.1-based analysis for TPH, instead

perform a Gas Chromatography/Flame Ionization Detection

(GC/FID) analysis for TPH using the spilled substance as a

calibration standard. GC/FID methods can be sufficient for

screening purposes when the oil contamination is fresh*,

unweathered oil and when one is fairly sure of the source

[657]. If diesel 1D was spilled, perform TPH-D (1D) using

California LUFT manual methods (typically a modified EPA

method 8015) [465] or a locally available GC/FID method of

equal utility for the product spilled. However, no matter

which TPH method is used, whether based on various GC/FID or

EPA method 418.1 protocols, the investigator should keep in

mind that the effectiveness of the method typically changes as

oil ages, that false positives or false negatives are

possible, and that the better Gas Chromatography-Mass

Spectrometry-Selected Ion Mode (GC/MS/SIM) scans (such as the

NOAA expanded scan***) should probably be performed at the end

of remediation to be sure that the contamination has truly

been cleaned up. Another option for fresh oil: in cases where

an inexpensive screening scan is desired, consider using an

HPLC/Fluorescence scan method for sediment or bile metabolite

samples. Such scans are available from laboratories at Texas

A. and M., Arthur D. Little, and the NOAA lab in Seattle.

This scan is not much more expensive, and less prone to false

negatives and various other problems than some of the more

common screening methods (TPH-EPA 418.1 and Oil and Grease).

Screening measures the total fluorescence of oil components

while GC/MS measures individual aromatic compounds [521].

Thus, HPLC/fluorescence screening allowed detecting lower

concentrations of petroleum-related aromatic compounds in

samples contaminated by Prudhoe Bay Crude Oil than did

analysis by GC/MS [521].

3b. The spilled product is not fresh* or the contamination 

is of unknown or mixed composition........................6

4. Analyze for Benzene, Toluene, Ethyl Benzene, and Toluene

(BTEX) compounds in water as part of a broader scan of

volatiles using EPA GC/MS method 8240. The standard EPA GC/MS

method 8240 protocol will be sufficient for some applications,

but the standard EPA method 8240 (and especially the less

rigorous EPA BTEX methods such as method 8020 for soil and
method 602 for water) are all inadequate for generating

scientifically defensible information for Natural Resource

Damage Assessments [468]. The standard EPA methods are also

inadequate for risk assessment purposes. Thus, when

collecting information for possible use in a Natural Resource

Damage Assessment or risk assessment, it is best to ask the

lab to analyze for BTEX compounds and other volatile oil

compounds using a modified EPA GC/MS method 8240 method using

the lowest possible Selected Ion Mode detection limits and

increasing the analyte list to include as many alkyl BTEX

compounds as possible. Also analyze surface or (if

applicable) ground water samples for polycyclic aromatic

hydrocarbons (PAHs) and alkyl PAHs using the NOAA protocol

expanded scan*** modified for water samples using methylene

chloride extraction. If the contaminated water is

groundwater, before the groundwater is determined to be

remediated, also analyze some contaminated sub-surface soils

in contact with the groundwater for BTEX compounds (EPA GC/MS

method 8240), and PAHs (NOAA protocol expanded scan***). The

magnitude of any residual soil contamination will provide

insight about the likelihood of recontamination of groundwater

resources through equilibria partitioning mechanisms moving

contamination from soil to water.

5a. The medium of concern is sediments or soils..................6

5b. The medium of concern is biological tissues..................7

6. Perform the NOAA protocol expanded scan*** for polycyclic

aromatic hydrocarbons (PAHs) and alkyl PAHs. If there is any

reason to suspect fresh* or continuing contamination of soils

or sediments with lighter volatile compounds, also perform EPA

GC/MS method 8240 using the lowest possible Selected Ion Mode

(SIM) detection limits and increasing the analyte list to

include as many alkyl Benzene, Toluene, Ethyl Benzene, and

Xylene (BTEX) compounds as possible.

7a. The problem is direct coating (oiling) of wildlife or plants

with spilled oil product.....................................8

7b. The problem is something else................................9

8. Perform NOAA protocol expanded scan*** for polycyclic aromatic

hydrocarbons (PAHs) and alkyl PAHs and/or GC/FID

fingerprinting of the coating oil only if necessary to

identify the source or exact oil. If the source is known and

no confirmation lab studies are necessary: dispense with

additional chemical laboratory analyses and instead document

direct effects of coating: lethality, blinding, decreased

reproduction from eggshell coating, etc., and begin cleaning

activities if deemed potentially productive after consolations

with the Fish and Wildlife Agencies.

9a. The concern is for impacts on water column organisms (such as
fish or plankton)...........................................10

9b. The concern is for something else (including benthic

organisms)..................................................11

10. If exposure to fish is suspected, an HPLC/Fluorescence scan

for polycyclic aromatic hydrocarbon (PAH) metabolites in bile

may be performed to confirm exposure [844]. The

HPLC/fluorescence scan looks for the presence of metabolites

of PAHs: naphthalene, phenanthrene, and benzo[a]pyrene. The

technique does not identify or quantify actual PAH compounds,

but subsequent gas chromatography analyses can be done to

confirm the initial findings. Even the semi-quantitative

Total Scanning Fluorescence (TSF) done inexpensively by labs

such as GERG are a better measure of PAH contamination than

GC/FID, which measures less persistent and less hazardous

aliphatics. For bottom-dwelling fish such as flounders or

catfish, also analyze the bottom sediments (see Step 6 above).

Fish which spend most of their time free-swimming above the

bottom in the water column can often avoid toxicity from toxic

petroleum compounds in the water column, but if fish are

expiring in a confined** habitat (small pond, etc.), EPA GC/MS

method 8240 and the NOAA protocol expanded scan*** for PAHs

could be performed to see if Benzene, Toluene, Ethyl Benzene,

and Xylene (BTEX), naphthalene, and other potentially toxic

compounds are above known acute toxicity benchmark

concentrations. Zooplankton populations impacted by oil

usually recover fairly quickly unless they are impacted in

very confined** or shallow environments [835] and the above

BTEX and PAH water methods are often recommended rather than

direct analyses of zooplankton tissues.

11a. The concern is for benthic invertebrates: analyze invertebrate

whole-body tissue samples and surrounding sediment samples for

polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs using

the NOAA protocol expanded scan***. If the spill is fresh* or

the source continuous, risk assessment needs may also require

that the sediments which form the habitat for benthic

invertebrates be analyzed for Benzene, Toluene, Ethyl Benzene,

and Xylene (BTEX) and other volatile compounds using EPA GC/MS

method 8240 or modified EPA method 8240 in the Selected Ion

Mode (SIM). Bivalve invertebrates such as clams and mussels

do not break down PAHs as well or as quickly as do fish or

many wildlife species. They are also less mobile. Thus,

bivalve tissues are more often directly analyzed for PAH

residues than are the tissues of fish or wildlife.

11b. The concern is for plants or for vertebrate wildlife including

birds, mammals, reptiles, and amphibians: polycyclic aromatic

hydrocarbons (PAHs) and other petroleum hydrocarbons break

down fairly rapidly in many wildlife groups and tissues are

not usually analyzed directly. Instead direct effects are

investigated and water, soil, sediment, and food items

encountered by wildlife are usually analyzed for PAHs and
alkyl PAHs using the NOAA protocol expanded scan***. If the

spill is fresh* or the source continuous, risk assessment

needs may also require that these habitat media also be

analyzed for Benzene, Toluene, Ethyl Benzene, and Xylene

(BTEX) and other volatile compounds using EPA GC/MS method

8240 or modified EPA method 8240 in the Selected Ion Mode

(SIM). Less is known about plant effects. However, the same

methods recommended above for the analyses of water (Step 4

above) and for sediments or soils (Step 6 above) are usually

also recommended for these same media in plant or wildlife

habitats. If wildlife or plants are covered with oil, see

also Step 8 (above) regarding oiling issues. 

* Discussion of the significance of the word "fresh": The word

"fresh" cannot be universally defined because oil breaks down

faster in some environments than in others. In a hot, windy,

sunny, oil-microbe-rich, environment in the tropics, some of the

lighter and more volatile compounds (such as the Benzene, Toluene,

Ethyl Benzene, and Xylene compounds) would be expected to disappear

faster by evaporation into the environment and by biodegradation

than in a cold, no-wind, cloudy, oil-microbe-poor environment in

the arctic. In certain habitats, BTEX and other relatively water

soluble compounds will tend to move to groundwater and/or

subsurface soils (where degradation rates are typically slower than

in a sunny well aerated surface environment). Thus, the judgement

about whether or not oil contamination would be considered "fresh"

is a professional judgement based on a continuum of possible

scenarios. The closer in time to the original spill of nondegraded petroleum product, the greater degree the source is

continuous rather than the result of a one-time event, and the more

factors are present which would retard oil evaporation or breakdown

(cold, no-wind, cloudy, oil-microbe-poor conditions, etc.) the more

likely it would be that in the professional judgement experts the

oil would be considered "fresh." In other words, the degree of

freshness is a continuum which depends on the specific product

spilled and the specific habitat impacted. Except for groundwater

resources (where the breakdown can be much slower), the fresher the

middle distillate oil contamination is, the more one has to be

concerned about potential impacts of BTEX compounds, and other

lighter and more volatile petroleum compounds. 

To assist the reader in making decisions based on the continuum of

possible degrees of freshness, the following generalizations are

provided: Some of the lightest middle distillates (such as Jet

Fuels, Diesel, No. 2 Fuel Oil) are moderately volatile and soluble

and up to two-thirds of the spill amount could disappear from

surface waters after a few days [771,835]. Even heavier petroleum

substances, such as medium oils and most crude oils will evaporate

about one third of the product spilled within 24 hours [771].

Typically the volatile fractions disappear mostly by evaporating

into the atmosphere. However, in some cases, certain water soluble

fractions of oil including Benzene, Toluene, Ethyl Benzene, and

Xylene (BTEX) compounds move down into groundwater. BTEX compounds

are included in the more volatile and water soluble fractions, and
BTEX compounds as well as the lighter alkanes are broken down more

quickly by microbes than heavier semi-volatiles such as alkyl PAHs

and some of the heavier and more complex aliphatic compounds. Thus

after a week, or in some cases, after a few days, there is less

reason to analyze surface waters for BTEX or other volatile

compounds, and such analyses should be reserved more for

potentially contaminated groundwaters. In the same manner, as the

product ages, there is typically less reason to analyze for alkanes

using GC/FID techniques or TPH using EPA 418.1 methods, and more

reason to analyze for the more persistent alkyl PAHs using the NOAA

protocol expanded scan***. 

** Discussion of the significance of the word "confined": Like the

word "fresh" the word "confined" is difficult to define precisely

as there is a continuum of various degrees to which a habitat would

be considered "confined" versus "open." However, if one is

concerned about the well-being of ecological resources such as fish

which spend most of their time swimming freely above the bottom, it

makes more sense to spend a smaller proportion of analytical

funding for water column and surface water analyses of Benzene,

Toluene, Ethyl Benzene, and Xylene (BTEX) and other volatile or

acutely toxic compounds if the spill is in open and/or deep waters

rather than shallow or "confined" waters. This is because much of

the oil tends to stay with a surface slick or becomes tied up in

subsurface tar balls. The petroleum compounds which do pass

through the water column often tend to do so in small

concentrations and/or for short periods of time, and fish and other

pelagic or generally mobile species can often swim away to avoid

impacts from spilled oil in "open waters." Thus in many large oil

spills in open or deep waters, it has often been difficult or

impossible to attribute significant impacts to fish or other

pelagic or strong swimming mobile species in open waters.

Lethality has most often been associated with heavy exposure of

juvenile fish to large amounts of oil products moving rapidly into

shallow or confined waters [835]. Different fish species vary in

their sensitivity to oil [835]. However, the bottom line is that

in past ecological assessments of spills, often too much money has

been spent on water column analyses in open water settings, when

the majority of significant impacts tended to be concentrated in

other habitats, such as benthic, shoreline, and surface microlayer

habitats.

*** The expanded scan protocols for polycyclic aromatic

hydrocarbons (PAHs) and alkyl PAHs have been published by NOAA

[828].

End of Decision Tree Key.

It is important to understand that contaminants data from

different labs, different states, and different agencies, collected

by different people, are often not very comparable (see also,

discussion in the disclaimer section at the top of this entry).

As of 1997, the problem of lack of data comparability (not

only for water methods but also for soil, sediment, and tissue
methods) between different "standard methods" recommended by

different agencies seemed to be getting worse, if anything, rather

than better. The trend in quality assurance seemed to be for

various agencies, including the EPA and others, to insist on

quality assurance plans for each project. In addition to quality

control steps (blanks, duplicates, spikes, etc.), these quality

assurance plans call for a step of insuring data comparability

[1015,1017]. However, the data comparability step is often not

given sufficient consideration. The tendency of agency guidance

(such as EPA SW-846 methods and some other new EPA methods for bioconcentratable substances) to allow more and more flexibility to

select options at various points along the way, makes it harder in

insure data comparability or method validity. Even volunteer

monitoring programs are now strongly encouraged to develop and use

quality assurance project plans [1015,1017]. 

At minimum, before using contaminants data from diverse

sources, one should determine that field collection methods,

detection limits, and lab quality control techniques were

acceptable and comparable. The goal is that the analysis in the

concentration range of the comparison benchmark concentration

should be very precise and accurate. 

It should be kept in mind that quality control field and lab

blanks and duplicates will not help in the data quality assurance

goal as well as intended if one is using a method prone to false

negatives. Methods may be prone to false negatives due to the use

of detection limits that are too high, the loss of contaminants

through inappropriate handling, or the use of inappropriate

methods. The use of inappropriate methods is particularly common

related to oil products.

Additonal detail:

The relative proportions of hazardous compound constituents

present in petroleum-based oil contamination is typically quite

variable. The lab analyses most appropriate for measuring

different types of oil contamination depend upon the type of oil

involved and the reason for measuring the contamination. The

farther one progresses from lighter towards heavier oils (the

general progression from light towards heavy is the following:

Diesel, No. 2 Fuel Oil, Light Crudes, Medium Crude Oils, Heavy

Crudes, No. 6 Fuel Oil, etc.) the greater the percentage of PAHs

and other semi-volatiles (many of which are not so immediately

toxic as the volatiles but which can result in long-term/chronic

impacts). These heavier oils thus need to be analyzed for the semi

volatile compounds which typically pose the greatest long-term

risk, PAHs and alkylated PAHs. 

Screening scans: Certain screening scans may be used to

monitor the position and magnitude of contamination. Below are a

few notes related to screening scans versus distillate fuels:

GC/FID: 

While a screening analysis such as GC/FID should be
adequate for mid-range products such as diesels, fuel oil

no. 2, and possibly jet fuels, lighter gasoline fractions

will be lost in a GC/FID analysis (which uses extraction

and burning) [657]. Distillate fuels in the C9 to C16

range normally have a boiling range well above the

boiling-point of benzene; accordingly, the benzene

content of this fraction is usually low [747]. 

Method 8015:

EPA Method 8015 (for Non-halogenated Volatile Organics)

is a gas chromatographic method sometimes recommended for

the analysis of volatile and semivolatile compounds. It

can be used to characterize light and midrange petroleum

distillates such as gasoline, diesel, fuel oil, and

kerosene. This method can be used to obtain some gross

fingerprint information for differentiation between

petroleum products, as well as detailed information that

can be used to differentiate between different batches of

the same product. The major limitation of Method 8015 is

its inability to detect nonvolatile compounds. The State

of California recommends a "modified method 8015"

(different from EPA's method 8015 and also different from

EPA method 418.1) for gasoline, kerosene, diesel oil, or

other fuels in soil and groundwater, as specified in the

Leaking Underground Fuel Tank (LUFT) Manual [465].

The California LUFT methods call for packed GC columns

which have poor resolving power and make it difficult to

obtain detailed information about the hydrocarbon type

[810]. Superior GC columns and superior methods (such as

ASTM 2887) are available [810]. For example, narrow-bore

capillary columns can analzye most of the gasoline,

entire diesel fractions, and a substantial portion of the

crude oil range [810].

Using the California LUFT manual methods, only an

experienced analyst will be able to differentiate diesel

fractions from aged gasoline [810]. The oversimplified

California methods and models are plagued with many

problems [808,810]. Choosing an appropriate solvent for

semivolatile analyses always presents a problem; some

solvents extract certain compounds better than others and

many present environmental or health risks [810].

HPLC screening scans:

In cases where a less expensive screening scan is

desired, consider using an HPLC/Fluorescence scan method

for sediment or bile metabolite samples. Such scans are

available from laboratories at Texas A. and M., Arthur D.

Little, and the NOAA lab in Seattle. This scan is less

prone to false negatives and various other problems than

some of the more common screening methods (TPH-EPA 418.1
and Oil and Grease). HPLC/Fluorescence is less expensive

than some of the more rigorous scans. The

HPLC/fluorescence scan can be used for analyses of fish

bile: the scan looks at bile directly for the presence of

metabolites of PAHs: naphthalene, phenanthrene, and

benzo(a)pyrene. The technique does not identify or

quantify actual PAH compounds, but subsequent gas

chromatography analyses can be done to confirm the

initial findings. Even the semi-quantitative Total

Scanning Fluorescence (TSF) done inexpensively by labs

such as GERG are a better measure of PAH contamination

than GC/FID, which measures less persistent and less

hazardous aliphatics. Additional Pros: HPLC Fluorescence screening

methods have been performed extensively by NOAA to

locate hotspots for crude oil contamination.

NOAA's experience with the Exxon Valdez spill

indicated that concentrations of aromatic

hydrocarbons measured by HPLC/Fluorescence

screening were highly correlated with the sums of

Aromatic hydrocarbons determined by GC/MS, thus

validating the screening method as an effective

tool for estimating concentrations of petroleumrelated aromatic hydrocarbons in sediments.

Moreover, differences in HPLC chromatographic

patterns among sediments suggested different

sources of contamination, e.g., crude oil or diesel

fuel. Allows crude determinations related to

sources: HPLC/Fluorescence analyses allowed at

least rough differentiation between aromatic

hydrocarbons which may have originated from diesel

fuel versus those from boat traffic [521] and The

procedure was successfully applied to

fingerprinting' gasolines, kerosines, diesel oils,

heavy fuel oils, lubricating oils, and ship bilge

oils [AUTHOR: Saner WA; Fitzgerald GE, II

PUBLICATION YEAR: 1976 TITLE: Thin-Layer

Chromatographic Technique for Identification of

Waterborne Petroleum Oils JOURNAL: Environmental

Science and Technology SOURCE: Vol. 10, No. 9, p

893-897, September 1976. 6 fig, 4 tab, 7 ref.]. 

EPA 418.1 for TPH:

Although EPA method 418.1: Petroleum Hydrocarbons

expressed as Total Petroleum Hydrocarbons (TPH), is

recommended by many State agencies, some consulting

firms, and some laboratories for certain regulatory

and screening applications (often leaking

underground storage tanks), this method is not well

suited to fuel oil no. 6 contamination or to the

more persistent hazardous constituents in oil. Low

values tend to give the mistaken impression that a
site is clean when it really isn't (prone to false

negatives). For example, a field test of

bioremediation of soils contaminated with Bunker C

at a refinery in Beaumont, Texas, utilized oil and

grease data, which (although the data was quite

variable) seemed to indicate bioremediation was

taking place [728]. A comparison of the oil and

grease data at this site with TPH data at this site

suggested the same thing, that the data was quite

variable but if anything, the oil was slowly being

cleaned up by bioremediation (Bruce Herbert, Texas

A. and M., Department of Geology, personal

communication, 1995). However, a later study of

the same site utilizing the expanded scan for PAHs

(a modified EPA 8270 including alkyl homologues and

lower detection limits), indicated that very little

bioremediation of hazardous alkyl PAHs and multiring PAHs was actually taking place [727]. Thus,

utilizing either oil and grease or TPH analyses

would tend to lead one to the faulty conclusion

that the harmful compounds were being naturally

cleaned up at an acceptable rate. This is partly

because the TPH and oil and grease methods tend to

favor the lighter and less alkylated PAHs, whereas

many of the carcinogenic and longer lasting PAHs

are the heavier multi-ringed and alkylated

compounds. For more information, see Petroleum

Hydrocarbons entry. 

See also: ATSDR toxicological profile on fuels oils in

general, including this product [962].

See also: Laboratory and/or Field Analyses section in Oil

Spills entry for information on biological indicators of oil

exposure.

See also: PAHs as a group and Fuel Oil, General entries.