Multivariate
analyses were used to assess the independent determinants of four organochlorines (OCs) in the fat and eggs of breeding female Great Shearwaters Puffinus gravis. The amounts of polychlorinated biphenyis (PCBs), DDE, DDT, and dieldrin, in both adult fat tissue and in eggs were positively correlated. However, there was no correlation between the amounts of OCs in adults and their eggs. Positive correlations between the amounts of different OCs in adults and in eggs suggest that individual differences in non-breeding range, diet and age are determinants of pollutant levels within a species. The mass of ingested plastic was positively correlated only with PCBs, a group of chemicals commonly found in plastics. It is probable that seabirds assimilate PCBs and other toxic chemicals partly from ingested plastic particles.
Polychlorinated biphenyls (PCBs) have become ubiquitous pollutants of marine food webs over the last 20 yr, and are particularly prevalent in seabirds (see Bourne, 1976; Ohlendorf et aL, 1978 for reviews). Although adverse effects from PCBs are not always apparent (Harris & Osborn, 1981), PCBs may have deleterious effects on birds, including reduced breeding success, increased risk of disease, and altered hormone levels, as well as direct mortality (e.,g.