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Reproductive Health in humans and wildlife
are adverse trends associated with environmental chemical exposure?
Harrison PT, Holmes P, Humfrey CD.
Sci Total Environ 1997 Oct 20;205(2-3):97-106
Medical Research Council Institute for Environment
and Health, University of Leicester, UK.
In recent years, evidence from disparate observations
has indicated adverse changes in the reproductive health and fecundity
of animals and humans. In humans, there is strong evidence for such
trends in the incidences of testicular and female breast cancer,
and concern has also been expressed regarding semen quality, cryptorchidism,
hypospadias and polycystic ovaries. Laboratory studies have indicated
that some chemicals in the environment, both natural and synthetic,
have the potential to disrupt the endocrine system and that these
could, at least theoretically, be partly responsible for the observed
changes. Chemicals thus identified include the naturally occurring
steroid hormones, phyto- and myco-estrogens, and anthropogenic chemicals
such as synthetic hormones, organotins, organochlorine pesticides,
polychlorinated biphenyls, dioxins, alkylphenol polyethoxylates,
phthalates and bisphenol-A. While there is no direct evidence from
human studies to confirm a causal link between exposure and effect,
concern exists and is strengthened by reports of adverse reproductive
and developmental effects in wildlife, possibly mediated via endocrine
disruptive pathways. The development of imposex in neogastropod
molluscs exposed to tributyltin has been attributed to such a mechanism
and in wild populations of fish, alligators and birds, instances
of masculinisation or feminisation in polluted areas have been noted.
Among mammals, disturbed fertility of Florida panthers and some
marine species has also been reported. A concentrated research and
monitoring programme is required to clarify the nature and extent
of effects on reproductive health in humans and wildlife, and to
assess human and wildlife exposure to relevant naturally occurring
or anthropogenic endocrine disrupting substances. This will enable
a more robust evaluation of the contribution that environmental
chemical exposure may have on adverse trends in the reproductive
health of humans and wildlife.
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