Embryonic Mortality and Chromosomal Alterations Caused by Aroclor 1254 in Ring Doves

The breeding success of Ring Doves (Streptopelia risoria) fed Aroclor 1254 at 10 ppm was determined over two generations. Six pairs of birds were fed PCBs for three months, then allowed to incubate their clutch of two eggs. Eggs were then collected again for six months, at which time the birds were allowed to incubate another clutch. Results are given in Table 1. The low-hatching success of the second generation was due to heavy embryonic mortality. The age of embryonic death varied considerably but was mainly in the range of 3-8 days. This finding is at variance with that of Scott et al. (1), who found a significant decrease in hatchability of chicken eggs in the first generation with 10 ppm Aroclor 1248 for eight weeks and almost complete failure at both four and eight weeks at 20 ppm Aroclor 1248. In this case mortality occurred immediately before hatching. Eggshell thinning was not observed in either the first or second generation (2, 3). This is in agreement with the findings of Dahlgren and Linder (4) for the pheasant (Phasianus colchicus) and Heath et al. (5) for the Mallard (Anas platyrhynchos). Cytogenetic studies were performed on 24 dove embryos at 3-6 days of incubation. Six embryos were from dove pairs not fed PCBs (control), 17 embryos were from PCB-fed (10 ppm in diet) pairs and one embryo was irradiated with 155