Donald C . Malins .Vorthwest and Alaska Fisheries Center Seattle, Wash. 981 12
In her perceptive book, Silent Spring, Rachel Carson described how we have polluted the environment and thus threatened the survival of many forms of life, including our own. In the 1960’s, her warnings echoed throughout the world and we learned to fear chemicals. such as toxic metals and chlorinated hydrocarbons. The marine environment is the recipient of many of these chemicals; they are widely distributed in seawater, sediments, and organisms. 32 Environmental Science & Technology
Today. using sophisticated analytical techniques, we are searching for many different types of pollutants in marine and estuarine environments such as the New York Bight and Puget Sound, Wash. We want to learn where these compounds accumulate and whether they are adverselq affecting marine life. Our views of marine pollution are changing. W e are just now beginning to fully appreciate the tremendous immensity and complexity of the problem. Today, there are an estimated 63 000 chemicals i n common use. Pesticides alone contain some I500 active ingredients. The registry of chemicals of the American Chemi-
cal Society. which contains over four million entries, is growing by an astounding 6000 each week. Many of these chemicals-some created to satisfy technological and economic demands-will eventually find their way into the marine system, adding to the environmental load. We know, for example, that an estimated four million metric tons of petroleum c nt e r the ni a r i ne e nv i r on nie n t each year. Thus, to protect our natural resources we must look into the effects of chemical pollutants on marine organi xnis a nd the i r habitat s. Many pollutants, such as polychlorinated biphenyls (PCB’s), are resistant to chemical and biological
0013-936X/79/0913-0122$01.00/0
@ 1979 American Chemical Society
changes and thus can remain in the marine environment for years. Other organic compounds are readily transformed into a host of “new” chemical structures. Most of these products escape the chemist’s eye; that is, they cannot be detected in marine samples, even with our most sophisticated analytical techniques. For example, the pattern of volatile hydrocarbon components, as determined by gas chromatography, is used as an index of the presence of petroleum pollution in marine samples. But this approach may not be realistic. Crude oils consist primarily of hydrocarbons, but may contain as much as 50% polar organic compounds. Most of the hydrocarbons are readily oxidized in marine environments through chemical and biochemical reactions into a variety of polar organic compounds of unknown toxicity to marine life. These “new” compounds, because of their relatively low volatility, their thermal instability, or both, are not quantifiable by gas chromatographic techniques. They can be analyzed by high-performance liquid chromatography, but we have a long way to go in applying this to the rou. tine analysis of marine sampies. Thus, there are many toxic chemicals in the marine environment that currently remain undetected. In the Environmental Conservation Division of the Northwest and Alaska Fisheries Center, we are attempting to solve problems involved in identifying chemical pollution in marine environments and in relating the findings to possible alterations in the health of marine organisms. I will describe our interdisciplinary approach to these complex issues and show how it is possible to resolve some of the problems we face through research in the laboratory and field. Our teams are made up of specialists in analytical chemists, biochemists, vertebrate and invertebrate pathologists, electron microscopists, immunologists, and behavioral biologists. Analysis difficulties It is important to understand that we face a number of limitations in our efforts to analyze marine pollutants. For example, when we find certain patterns of hydrocarbons in samples of water, sediment, or organisms, we can often infer that the source of the hydrocarbons is petroleum. Conversely, however, when we do not find hydrocarbons in samples, this does not necessarily mean that they are free of petroleum contamination because, as stated previously, the parent compounds may have been converted to
nonvolatile polar derivatives. Thus, our inability to analyze the myriad nonvolatile products often limits our perception of the extent and severity of petroleum pollution. A primary concern is not really whether pollutants are present in the marine environment, but whether they are available to organisms. For example, many pollutants are found in sediments, but they are not all taken up by marine life to the same extent. The PCB’s in sediments tend to accumulate in tissues of bottom-dwelling fish to a greater degree than do aromatic hydrocarbons. This difference may be explained, in part, by the fact that the aromatic hydrocarbons are rapidly oxidized in the livers of fish whereas the PCB’s are transformed relatively slowly. W e have learned that flatfish exposed to petroleum-contaminated sediment do not accumulate to a great degree a number of higher molecular weight aromatic hydrocarbons, such as fluorene or the carcinogen benzo [ a ]pyrene. In contrast, the one- and tworing aromatic structures, such as the alkyl benzenes and certain methylnaphthalenes, are accumulated to a considerable degree. W e look to differences in hydrocarbon-sediment binding properties and to differences in the rates of bioconversions of hydrocarbons in the flatfish to explain these findings. Another concern is whether pollutants are transferred through marine food webs. Studies relating to this issue are difficult to conduct and relatively few investigators have accepted the e. W e know that toxic metals s are readily passed through od webs, but it appears that the petroleum hydrocarbons are not transferred extensively because enz y v systems in marine Organisms converl them to oxygenated products-a process that naturally limits hydrocarbons available to a predator. From the point of view of protecting our marine resources, perhaps the most important question is “Are pollutants affecting the health of marine organisms?” To answer this question, we need to know which pollutants animals are exposed to in the environment, which ones they tend to accumulate, what happens to the pollutants inside the animals, and what are the biological changes accompanying these events. Approach to the problem In my opinion, the question is best answered through interdisciplinary research conducted by teams of sci-
The NAF marine pollution investigative team
Bruce McCain testing f o r liver tumors
Edward Gruger, Jr. with spectrophotometer
Joyce Hawkes using electron microscope
Margaret Krahn liquid chromatography Volume 14, Number 1, January 1980
33
Ma’or aromatic hydrocarbons in rudhoe Bay crude oil contaminated sediments
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5. 1-Methylnaphthalene 6. Biphenyl 7. 2,&Dimethylnaphthalene 8. 2,3,5-Trimethylnaphthalene
Souffis: McCain B B and D.C Matins (1879) Uptake fate and effects of aromatrc h drocarbonson selected fish and crustaceans fmm the Northeast PacMc Ocean. Presented at the Marine
