Distribution of Chlorinated Hydrocarbon Pesticides and PCBs in the ...

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measure concentrations of these compounds in marine biota
at various trophic levels to determine whether
biomagnification occurs; and
evaluate the importance of the atmospheric contribution of
these contaminants.
There are a large number of chlorinated hydrocarbon
pesticides that have been or are presently in use. Because of
concerns over their environmental effects, the use of many of the
more persistent pesticides has been banned in the United States,
Canada and western Europe. However, banned compounds are still
being used in large tonnages in other countries particularly in
the tropics and the ban on the use of many others has only been
in effect during the past few years. A summary of recent FA0
/reported1 worldwide usage of organochlorine pesticides whose use
or production has been halted in the United States is given in
Table 1.1 (from Bidleman, 1987). As pointed out by Bidleman,
these figures likely grossly underestimate the total amount of
pesticide used as reporting of these figures to the FA0 is
voluntary.
A total of 20 organochlorine pesticides were monitored in
this study. PCBs in this study were defined in terms of a
particular technical mixture, Arochlor 1254. Since reference to
these compounds will be made throughout the text and since most
have short form or common names different from their actual
chemical nomenclature, a list is given in Table 1.2 of the target
compounds in this study and the corresponding short form name
that will be used in the text. Some of the pesticides have
several stable isomers and others are metabolites or degradation
products or are present in the same technical mixtures and hence
share common origins and have similar physical and chemical
properties. On this basis the target compounds can be grouped
into 5 classes: hexachlorocyclohexanes (HCH), hexachlorobenzene
(HCB) , Cyclodienes, DDT, and PCBs. This grouping of compounds
has been used in the discussion of the data.