Marine Biochemistry 



The increased understanding of the uptake, metabolism, and effects of pollutants 

 in the marine biosphere has given us a basis for assessing potential effects and 

 formulating control measures. New definitions of toxicity have evolved and field 

 measurements for toxic effects on some organisms are now possible. 



Extensive work has been performed on the pathways of metals through marine 

 organisms, and it has been well summarized recently by George ( 1980). For phyto- 

 plankton and shellfish, the initial uptake of dissolved phases is consistent with 

 passive diffusion, i.e., an initial adsorption to an exposed mucous sheet or cell 

 membrane, followed by diffusion and binding to intracellular components. Metals 

 can also be taken up in particulate form from food, which may be of equal or greater 

 importance than the accumulation of dissolved forms. Some metals are bound 

 nonspecifically to cystosolic proteins. Excessive amounts of a metal may be 

 detoxified in a variety of ways. In some cases they are stored in sulfate or phosphate 

 granules, or directed to the shell, byssal threads, or carapaces. 



The studies on the marine biochemistry of halogenated and petroleum hydro- 

 carbons have paralleled those of heavy metals. Copepods enzymatically metabolize 

 petroleum hydrocarbons to hydroxylated forms that are later excreted (Lee, 1975). 

 These organisms can take up dissolved or particulate forms of the hydrocarbons 

 from water or from food. The pollutants concentrate in the livers or gall bladders of 

 fish and are subsequently discharged in the urine or feces (Lee et al., 1972). 



THE TITRATION 



Over the past three decades, environmental scientists have identified a large 

 number of polluting substances entering the oceans and potentially capable of inter- 

 fering with public health, the vitality of marine organisms, and the nonliving 

 resources of the sea. Those responsible for the management of the coastal environ- 

 ment have been able to react in decades or less to available information from the 

 scientists. Thus, the experiences with marine pollution and with marine chemistry 

 can act as an information base for considering the abilities of the marine environ- 

 ment to accept some of the large-scale wastes of human beings. Much of the material 

 in the following presentation derives from the deliberations of 70 scientists at the 

 Crystal Mountain Workshop, held in August 1979 (NOAA, 1980). 



The assimilative capacity of a marine water body may be defined as that amount of 

 a given material that can be contained within a body of sea water without producing 

 an unacceptable impact, be it upon livingorganisms or upon the nonliving resources. 

 This amount, essentially determined by a titration of the polluting substances in the 

 discharged material with the water body becomes evident at an endpoint. Pollutant 

 concentrations that are determined before the endpoint is reached are checkpoints. 

 The most extensive set of endpoints for individual pollutants has evolved from arti- 

 ficial radioactivity studies. For example, the unacceptable concentration of 

 ruthenium-106 in the seaweed Porphyra, taken from the seawaters adjacent to the 

 Windscaie Reprocessing Plant in the United Kingdom, would constitute an end- 

 point. The 0.5 ppm level of mercury in fish provides an endpoint that protects the 

 heavy fish-eating populations of the world. 



With the titration concept, models have been constructed to seek out the assimila- 

 tive capacities of seawater utilizing existing data (NOAA, 1980). Although such 

 models will be refined with additional data, theirconstructionemphasiz.es that there 

 is a scientific basis for regulating the discharge of wastes to coastal waters. 



The overall conclusion from the Crystal Mountain Workshop is that the waste 

 capacity of U.S. coastal waters is not now fully used. For example, the largest U.S. 

 industrial dumpsite (Site 106 off the coast of New Jersey), which receives about 

 800,000 m (1,048,000 yd ) year of titanium dioxide production wastes, organic 

 chemical wastes, and water treatment materials, is not used to its total assimilative 



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