Reproductive toxicity environmental contaminants

For the sake of completeness, this chapter will also discuss the adverse reproductive effects of potential toxicants, such as ionizing radiation, pesticides and other organic environmental contaminants, as well as heavy metals, which are... 

Much of the evidence for the adverse reproductive effects of selected toxicants will be based on cases involving wildlife exposures to environmental contaminants or on the experimental results of research exposing laboratory animals to large, pharmacological doses of potential toxicants. When available, data will be presented from accidental or intentional human and domestic animal exposures to toxicants associated with riot control and chemical warfare or with environmental catastrophes where incidences of infertility, abortion, and teratogenesis have been traced over the course of a number of years. 

Unfortunately, many of the compounds dropped from these lists come from chemical classes that are known to contain examples that are of concern to human health (Figure 1). Some, for example, show evidence of carcinogenicity and reproductive toxicity in humans and/or experimental animals (as categorized by the International Agency for Research on Cancer [IARC]) others show a large potential environmental impact and have been slated for inclusion on the EPA s ground water contamination survey (5). 

In contrast, the avian toxicity tests have been developed over the last two decades in order to assess the effects of environmental contaminants, especially the effects of pesticides to nontarget species. The methods are similar in general to other short-term toxicity tests. A variety of species from different families of birds have been used, although standardization as to strain of each species has not been as extensive as with the mammalian toxicity tests. Examples of an acute feeding study and a reproductive test are presented in Table 4.8 and Table 4.9. 

We now know that PCB are hepatotoxlc and that they impair reproductive function and produce cancer in experimental animals (2,3). PCB undergo food chain "biomagnification" and accumulate in human and animal tissues, sometimes exceeding acceptable levels. As a result of the once valued stability and potential for chronic or delayed toxicity, widespread environmental contamination by PCB is now viewed as a threat to both environmental quality and public health (4). 

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