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PAPER
2
Sources, fates and ecosystem effects of Endocrine Disruptors in the
environment
Professor D. Michael Fry Department of Animal Science, University
of California Davis, USA.
Endocrine active compounds in the environment are derived from three
principle sources: household and industrial effluent discharged through
normal sewage treatment plants; untreated storm drain effluents; and
untreated agricultural runoff and drain water. The urban compounds
include human urinary excretion of pharmaceutical estrogens, and industrial
surfactants containing alkylphenol polyethoxylate (APOE) derivatives.
Storm-drain waters may contain pesticides, especially from golf courses
and domestic gardens. Agricultural runoff is a source of pesticides
and APEO used as mixing agents for agricultural chemicals, as well
as natural hormonal steroids in farm animal waste, especially from
poultry production and feedlots.
The amount of xenoestrogen discharge from urban sources is a function
of the effectiveness of the sewage treatment systems in degrading
the products. APEO may be partially converted to the alkylphenols,
and conjugated natural hormones may be converted to the active hormone
by sewage bacterial cultures. The estrogenic plume from a treatment
works may extend 1-5 km downstream from the discharge point.
The mixing agents for pesticides and herbicides are generally considered
"inert" ingredients, and not subject to the same reporting laws as
active ingredients, so that little information on quantity of APEO
use in agriculture is available. In California, APEO use is about
3% of total agricultural chemical use. Estrogenic compounds have been
detected in Californian rivers in agricultural areas, but the compounds
responsible have not been identified.
Agricultural use of APEO may result in terrestrial wildlife exposure
through direct contact and consumption of exposed foliage or insects.
If a combination of estrogenic pesticides (methoxychlor, dicofol,
DDT, lindane, endosulfan) and mixing agents are present, the effects
of the compounds could be additive.
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