The International Mussel Watch Program 



The Environmental Levels of Chlorinated Hydrocarbons 



We are concerned about the consequences of the continuing, and in some regions, 

 increasing use of chlorinated pesticides and the release and persistence in the environment of 

 industrial chemicals, e.g. polychlorinated biphenyls, especially in the tropical and southern 

 hemispheric regions of the world. Our particular interest encompasses the levels of these 

 organochlorine molecules in the coastal marine environment and the possible implications for 

 human health, restriction in uses of marine resources and impacts upon coastal ecosystems. 



There is strong evidence of an ever increasing usage of chlorinated hydrocarbon pesticides 

 in the developing world, especially in the tropics and in the southern hemisphere, based upon 

 analysis of the atmosphere, natural waters (Tanabe et al., 1982) and human mother's milk (Slorach 

 and Vaz, 1983), as well as examinations of the global production and use data of these biocides 

 (Postel, 1987). The concern of environmental scientists relates to a possible recurrence of the 

 ecodisasters that occurred in the northern hemisphere in the 1960's and 1970's as a consequence of 

 heavy use of DDT and similar pesticides impacting upon non-target organisms (Goldberg, 1976). 

 The production and use of organochlorine insecticides in the European OECD countries and North 

 America reached a peak value in the early 1970's. At that time ecological effects were observed in 

 top marine predator species, through egg-shell thinning in birds and reproductive failures in marine 

 mammals. 



In 1972, observations of the morbidities, mortalities and reproductive failures of higher 

 trophic level organisms including fish-eating birds led the United States Environmental Protection 

 Agency to ban the use of DDT in agriculture and public health activities (Goldberg, 1976). This 

 action was repeated in many northern European countries. It must be emphasized that regulating 

 the flows of toxic chemicals to the environment had previously been based upon insults of human 

 health. This most sophisticated and advanced step of environmental action to maintain the integrity 

 of communities of organisms has been followed in many other cases. 



Following stringent environmental legislation, the use of chlorinated insecticides in the 

 U.S. and OECD countries gradually decreased. However, complementary use increased in 

 tropical areas and in the southern hemisphere. Subsequently, production and use shifted from 

 north to south. 



Following the decrease in use, levels of organochlorine pesticides in marine biota gradually 

 diminished in North America, Northern Europe and Japan (Slorach and Vaz, 1983). In the Baltic, 

 present levels are down to one-third of the levels of the early 1970's. Recently, however, the 



