Developmental toxicity of in ovo exposure to polychlorinated biphenyls: I. Immediate and subsequent effects on first‐generation nestling American kestrels ( Falco sparverius )

We determined that in ovo exposure to polychlorinated biphenyls (PCBs) alters growth off first‐generation nestlings during and one year after parental exposure. Captive American kestrels ( Falco sparverius ) laid eggs with environmentally relevant total PCB levels (34.1 μg/g whole‐egg wet wt) when fed PCB‐spiked (Aroclor® 1248, 1254, and 1260) food (7 mg/kg body wt/d) for 100 d in 1998. In 1999, the same adults laid eggs with estimated total PCBs of 29.0 μg/g. Nonsurviving PCB‐exposed chicks were small (mass, bones) in 1998. Survivors showed a strong sex‐specific growth response (mass, bones) compared to respective sex controls: Only female hatchlings were larger, and only male nestlings had longer feathers (1998); maximal growth and bone growth rates also differed (males were advanced, faster; females delayed, slower) (1999); and male nestlings fledged earlier and were smaller, while females were larger (1998, 1999). However, regardless of sex, PCB‐exposed nestlings generally grew at faster rates in both years. In 1998, greater contaminant burdens and toxic equivalent concentrations in sibling eggs were associated with nestlings being lighter, having longer bones and feathers, and growing at faster rates (mass, bone) for females but slower rates (mass) for males. Both physiological‐biochemical and behavioral changes are likely mechanisms. This study supports and expands on the Great Lakes embryo mortality, edema, and deformities syndrome: While PCB exposure alters nestling size, maximal growth and growth rates also change immediately, are sustained, and are sex specific.