Geoscience Reference
In-Depth Information
Fig. 4.2
General chemical structures of some organochlorine insecticides
exchange and generating severe metabolic acidosis. High tissue concentrations of
organochlorines increase myocardial irritability, predisposing to cardiac arrhyth-
mia. Human absorption of organochlorine sufficient to cause enzyme induction is
likely to occur only as a result of prolonged intensive exposure.
There has been considerable interest recently in the interaction of organochl-
orines with endocrine receptors, particularly estrogen and androgen receptors. In
vitro studies and animal experimentation support the view that the function of the
endocrine system may be altered by these interactions. This in turn may alter the
reproductive development and success of animals and humans. The International
Association for Research on Cancer evaluated organochlorine insecticides as being
either possibly carcinogenic to humans (DDT, chlordane, heptachlor, toxaphene)
or not classifiable as to carcinogenicity (aldrin, dieldrin, lindane) (IARC
1987
,
1991
,
2001
). Inconclusive epidemiological studies linked organochlorine insecti-
cides to increased risks of soft tissue sarcoma, non-Hodgkin's lymphoma, leuke-
mia, and prostate, lung, pancreas, and breast cancers (Purdue et al.
2006
). Due to
evidence of their toxicity and carcinogenic potential, some organochlorines have
been banned or restricted for use. Several organochlorine pesticides, including
DDT, methoxychlor, endosulfan, and dicofol, mimic estrogen (Gillette et al.
1994
;
Cummings
1997
). Lindane, which is sometimes used to treat head lice in children,
acts as an antiestrogen and is toxic to the nervous system (Cooper et al.
1989
).
