Environmental Chemistry is a relatively young science. Interest in this subject, however, is growing very rapidly and, although no agreement has been reached as yet about the exact content and limits of this interdisciplinary discipline, there appears to be increasing interest in seeing environmental topics which are based on chemistry embodied in this subject. One of the first objectives of Environmental Chemistry must be the study of the environment and of natural chemical processes which occur in the environment. A major purpose of this series on Environmental Chemistry, therefore, is to present a reasonably uniform view of various aspects of the chemistry of the environment and chemical reactions occurring in the environment. The industrial activities of man have given a new dimension to Environmental Chemistry. We have now synthesized and described over five million chemical compounds and chemical industry produces about hundred and fifty million tons of synthetic chemicals annually. We ship billions of tons of oil per year and through mining operations and other geophysical modifications, large quantities of inorganic and organic materials are released from their natural deposits. Cities and metropolitan areas of up to 15 million inhabitants produce large quantities of waste in relatively small and confined areas. Much of the chemical products and waste products of modern society are released into the environment either during production, storage, transport, use or ultimate disposal. These released materials participate in natural cycles and reactions and frequently lead to interference and disturbance of natural systems.

A distinction between contamination and pollution is useful when we wish to consider what strategies to adopt in researching the impact of anthropogenic activities on the marine environment. Contamination strictly refers to the chemical burden imposed on the system and is evaluated in terms of the concentrations of chemical compounds in various abiotic (e. g water, suspended particulate matter, sediments) and biotic (plant and animal, pelagic and benthic) components. The concept of pollution, on the other hand, infers an assessment of biological response to the measured levels of contamination. This response may be measured at various levels of biological organisation, from molecular events within the cell to changes in such ecosystem properties as nutrient flux and biological productivity. Such measures of biological response need not infer any value judgements regarding putative damage or disturbance to the natural systems, although the biologist will usually have in mind a reference point of normality with which to compare the measured response; departure from this "normality" may then provide a quantitiative index of disturbance. The challenge to scientists engaged in research into marine contamination and pollution is to weld the chemical and biological elements together (always with reference also to the physical features of the environment) so as to provide a coherent framework for the quantitative evaluation of environmental response.