Abstract
During the 1999 nesting season, eggs and nestlings of anhingas (Anhinga anhinga) and white ibises (Eudocimus albus) were collected from a colony located on the site of a municipal solid-waste (MSW) combustor and analyzed for residues of chemicals potentially released from this facility. Concentrations of most residues, including tetrachlorodibenzo-p-dioxin (TCDD), tetrachlorodibenzofuran (TCDF), arsenic, beryllium, cadmium and lead, were at levels comparable to those found during a similar survey done in 1989, prior to facility start-up. Nickel residues were detected only sporadically in anhingas and in eggs from ibises, and decreased significantly in concentration in ibis nestlings in 1999 compared to 1989. While concentrations of mercury in anhinga nestlings and in eggs of both species were comparable to 1989 levels, its concentration was significantly greater in ibis nestlings in 1999. However, levels of mercury in the ibises remained relatively low when compared to birds from other areas of Florida and did not appear to represent a health threat. While lead did not increase in 1999, its concentration in ibis nestlings remained a concern. The most notable temporal trend observed in birds at this site was a general monotonic decrease in levels of selenium residues during the 10-year monitoring period.