An Overview of the Biogeochemistry of Fossil Fuel Hydrocarbons in

1 A n Overview of the Biogeochemistry of Fossil Fuel Hydrocarbons in the Marine Environment

Downloaded by NEW YORK UNIV on June 8, 2015 | http://pubs.acs.org Publication Date: May 1, 1980 | doi: 10.1021/ba-1980-0185.ch001

JOHN W. FARRINGTON Department of Chemistry, Woods Hole Oceanographic Institution, Woods Hole, M A 02543 Analyses of hydrocarbons in the aquatic environment are reviewed within the context of biogeochemical research. Intercalibration of analyses of hydrocarbons in surface sediments shows discrepancy among data reported by different laboratories by as much as a factor of 30. Chronic release of fossil fuel compounds to the marine environment from fossil fuel combustion, sewage sludge, and harbor dredge spoils is discussed. Examples cited and discussed include studies of New York Bight surface sediments and mussels and oysters from the U.S. East and Gulf Coasts using glass capillary gas chromatography-mass spectrometer-computer systems analyses of aromatic hydrocarbons. Recommendations for future studies are presented and range from "bench chemistry" solubility studies to studies of the global transport of hydrocarbons by aeolian and fluvial processes.

" D iogeochemical studies of fossil fuel hydrocarbons provide information on inputs, routes, and rates of transfers and reaction, and reservoirs of accumulation of these compounds i n aquatic environments. Such research is necessary i n conjunction with research on the lethal and sublethal effects of fossil fuel compounds on aquatic ecosystems. They tell us where and for how long organisms w i l l be i n contact w i t h these compounds and what the form of the compound w i l l be (e.g., dissolved, colloidal, particulate, adsorbed on sediment). Throughout this chapter I w i l l refer primarily to studies of marine ecosystems. Generally the results are applicable to riverine and lacustrine 0-8412-0475-6/80/33/001$05.50/0 © 1980 American Chemical Society

In Petroleum in the Marine Environment; Petrakis, L., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1980.


2

PETROLEUM

IN T H E M A R I N E E N V I R O N M E N T

ecosystems, although each type has unique properties and warrants separate, focused studies. To date, marine ecosystems have received most of the attention because of the variety and magnitude of fossil fuel inputs. Freshwater ecosystems should receive increasing attention i n the future, as w i l l be demonstrated later in this chapter. I w i l l also limit the chapter primarily to hydrocarbons with more than 15 carbon atoms. Early biogeochemical studies of fossil fuel compounds i n the marine environment involved observing the disappearance of slicks from the surface of bodies of water. Surveys of the distribution and frequency of "tar balls" on the East Coast of the United States in the 1950s documented one fate of oil spilled into the ocean ( 1 ). Another chapter i n this volume deals with present efforts to understand the biogeochemistry of "tar balls" in a more broadly defined but scientifically rigorous manner. Other chapters i n this volume deal w i t h analytical techniques to detect trace quantities of fossil fuel compounds i n environmental samples. This is a results of progress from an out-of-sight-out-of-mind, or the oil slick disappeared-all is well, philosophy to a fuller realization of the complexity of the biogeochemistry of fossil fuel compounds i n aquatic environments. A stylized representation of the fate of oil inputs taken from a variety of studies since 1969 (1,2) is presented in Figure 1. Although we know that most of the pathways shown in Figure 1 are important, we still do not have a quantitative measure of the relative importance of each for different types of inputs. However, substantial progress has been made towards this goal as reported i n a number of recent reviews and symposia (2-10). For example, we know that oil spills are only a small part of the total oil input to the marine environment. A perusal of Tables I and II shows that chronic releases such as municipal and industrial effluents and river discharges account for a fairly large portion of the inputs. W e also know that under certain circumstances spilled oil can continue to contaminate intertidal sediments for at least five years (11,12). The continuing research challenge can be stated as follows: petroleum is a complex mixture of tens of thousands or more chemicals. This complex chemical soup is discharged into the aquatic environment, itself a complex chemical soup, then acted on by a variety of physical, chemical, biological, and geological processes such as wind, waves, heat, light, oxygen, microbial degradation, metabolism by fish, and adsorption onto particulate matter. During and after all this interaction the geochemist wants to know, "Where did all the petrochemicals go and why?" The various biological and ecological disciplines want to know what the effects were over time spans of hours to a decade or longer, for levels of biological organization from cells to ecosystems. Throughout the research aimed at answering these questions there has been a challenging need


1.

FABRiNGTON

3

Biogeochemistry of Fossil Fuel Hydrocarbons

PHOTOCHEMICAL REACTIONS

7 ROCKS


BEACHES

IDISSOLUTIONI

INGESTION BY MARINE LIFE

SEDIMENTSb Τ

BIOCHEMICAL OXIDATION

RATE? Figure 1.

BURIAL AS GEOCHEMICAL DEPOSIT

Stylized outline of fate of oil inputs to the marine environment

Table I .

Estimates f o r Petroleum Hydrocarbon Input to the Oceans (from Réf. 1)

Source M a r i n e transportation Offshore oil production Coastal oil refineries Industrial waste M u n i c i p a l waste Urban runoff R i v e r runoff" Subtotal N a t u r a l seeps Atmospheric rainout" Total

Ν AS Workshop (1973)

(mta)

a

2.133 0.08 0.2 0.3 0.3 0.3 1.6 4.913 0.6 0.6 6.113

° Millions of tons per annum. P H C input from recreational boating assumed to be incorporated in the river runoff value. Based upon assumed 10% return from the atmosphere. &

0


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PETROLEUM

Table II.

IN T H E M A R I N E E N V I R O N M E N T

Estimated Inputs of Petroleum Hydrocarbons i n the Ocean D u r i n g the E a r l y 1980s" Estimated Magnitude and Relative Confidence in Estimate fmta) b


Input Source Natural seeps Offshore production Transportation Coastal refineries Atmosphere Municipal and industrial Urban runoff River runoff Total Grand total

High

— 0.2 0.8 0.02

—

0.45

— —

1.47

Modest

Low

0.6

— — — —

— — — — —

0.3 1.6 2.5 4.57

0.6

— — —

0.6

—

Input values are directly subject to global output values that may experience major shifts because of political, financial, economic, or exploration/production con siderations. Millions of tons per annum. β

b

for obtaining measurements of fossil fuel compounds, more often than not at 10" -10" g / g sample concentration levels. Another challenge to analysts has been the application of analytical methods to the forensic approach of matching mystery oil spills w i t h the "spillee." This topic w i l l be addressed by another chapter in this volume. 6

Analytical

9

Methodology

Prior to the late 1960s measurements of total "grease and o i l " were the only routine analyses that would qualify as attempting to measure fossil fuels i n environmental samples—mainly sewage effluents or indus trial effluents. The measurement techniques varied but typically involved organic solvent extraction of grease, oil, and fats or lipids followed by either gravimetric determinations after evaporation of the solvent or I R spectrometry (13). During the late 1960s and early 1970s it was recog nized that more discriminating and sensitive analytical methodology had to be applied and/or developed to provide measurements of petroleum compounds i n environmental samples ( 1 , 3 ) . It was no longer sufficient to be able to measure total oil and grease i n samples i n which the fossil fuel compounds were present at such high concentrations that they over whelmed the concentrations of natural lipids. Measurements of fossil fuel compounds at concentrations less than natural lipids and even less than biogenic hydrocarbons were needed. Furthermore, the dynamics of the changing compositions of the fossil fuel compound mix as a result of microbial degradation, evaporation, and water/particle partitioning could


1.

Biogeochemistry of Fossil Fuel Hydrocarbons

FARRiNGTON

5


be better understood if more sophisticated analytical methods were employed. This resulted i n the application of a variety of column, thinlayer, and high-pressure liquid chromatography ( H P L C ) techniques to separate hydrocarbons from naturally occurring lipids and use of U V fluorescence, U V , I R , glass capillary gas chromatography, gas chromatography-mass spectrometry-computer system analyses of the separated hydrocarbons. One approach to such analyses is illustrated by the flowchart of one of the analytical schemes we have used i n our laboratory for the analysis of hydrocarbons i n sediments (Figure 2 ) . There are, of course, many SEDIMENT S0XHLET TRACTION

SAMPLE DIRECT SAPONIFICATION VIA ALKALINE HYDROLYSIS

ITOTAL EXTRACTABLESI

r

1

PARTITION INTO PENTANE I WEIGH

PARTITION INTO PENTANE I WEIGH

EXTRACTABLE LIPID MATERIAL ALKALINE HYDROLYSIS I WEIGH \ SAPONIFIABLE LIPID

NON-SAPONIFIABLE LIPID

ι

SULFUR REMOVAL

DISCARD

I

COLUMN CHROMATOGRAPHY I WEIGH

IHYDROfARB~UNS] X

1

ALKANES IAROMATICSI AROMATICS (

An Overview of the Biogeochemistry of Fossil Fuel Hydrocarbons in

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