has powerful low level effects on prostate development in mice.
to the US EPA, is used as an insecticide ("effective against
biting flies, houseflies, and mosquito larvae") and is considered
to be "an excellent replacement for DDT." In veterinary
practices, methoxychlor is used as an ectoparasiticide (a medicine
used to kill parasites that live on the exterior of their host).
The EPA reports that the Reference Dose (RfD) for methoxychlor is
0.005 mg/kg/d. EPA estimates that consumption of this dose or less,
over a lifetime, would not likely result in the occurrence of chronic,
noncancer effects. The EPA has set the "Maximum Contaminant
Level Goals" for methoxychlor
in drinking water at 40 parts per billion (ppb) because EPA
believes this level of protection would not cause any of the potential
health problems described below.
website providing information about toxicity of pesticides says:
is one of a few organochlorine pesticides that have seen an
increase in use since the ban on DDT in 1972. It is quite similar
in structure to DDT, but has relatively low toxicity
and relatively short persistence in biological systems. It is
available in wettable and dustable powders, emulsifiable conentrates,
granules, and an aerosol. It may be found in formulations with
malathion, parathion, piperonyl butoxide, and pyrethrins.
these reassurances, evidence is emerging that methoxychlor is a
potent endocrine disruptor.
in collaboration with vom Saal's laboratory, Wade Welshons et
al. reported in 1999 that extremely low-level methoxychlor exposure
causes dramatic changes in prostate and liver weights. Pregnant
mice were fed 20 parts per billion methoxychlor per day. Prostate
weight due to the resulting prenatal exposure to methoxychlor was
approximately 60% greater than controls (right). This level of contamination
is one half EPA's "Maximum Contaminant Level Goal" (i.e.,
what EPA recommends as the maximum allowable level in water) and
was the lowest dose tested. It is virtually certain that lower levels
have effects also.