Several recent reviews provide mounting evidence that PAHs can act as endocrine disruptors, alter reproductive hormones, and cause adverse effects in various reproductive functions. These compounds are likely to act by several different toxic mechanisms that would result in altered reproduction. One of the most important modes is their role as endocrine disruptors. As noted in one of the review articles, there are several studies demonstrating endocrine and reproductive effects in small mammals and humans from PAH exposure (mostly for BaP). The responses include adverse effects on thymic glucocorti-coid receptors, placental function, and oocyte and follicle integrity. Also, most rapidly proliferating cells are likely to be susceptible to PAHs. It is likely that these responses to PAH exposure are dependent on the life stage of the species that is exposed. Based on the known toxicological effects for PAHs, the early stages of life (development) are more susceptible to PAH exposure than other stages, such as juveniles and adults.
There are many reports of adverse effects on reproduction in a number of soil invertebrates that were exposed to several PAH compounds. For example, several PAHs elicited effects at concentrations ranging from 5 to 100 mg/g soil, with variability among species, compounds, endpoints, soil characteristics, and exposure time. A number of field studies have shown reproductive effects in flatfish due to PAH exposure. Even though field studies do not often result in definitive conclusions about specific contaminants, a few provide convincing cause and effect relationships that support PAHs as the causative agents.
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