FACTORS AFFECTING THE ACCUMULATION OF HEAVY METALS IN PASSERINE BIRDS AT THE TAR CREEK SUPERFUND SITE

Abstract

Exposure to lead (Pb), cadmium (Cd), and zinc (Zn) at the Tri-State Mining District and more specifically within the Tar Creek Superfund Site (TCSFS) is an ongoing issue for both humans and wildlife in the area. This study aims to find the concentrations of these metals in passerine birds living in and around this area, as well as to elucidate the effects of factors such as capture location, species, and migratory strategy on the tissue loads of these contaminants. To this end, Carolina Chickadees (Poecille carolinensis), Northern Cardinals (Cardinalis cardinalis), Tufted Titmice (Baeopholus bicolor), White-Throated Sparrows (Zonotrichia albicolis), Indigo Buntings (Passerina cyanea), and Painted Buntings (Passerina cirris) were captured over a period of several months and feather and whole blood samples were obtained and tested for Pb, Cd, and Zn. The results of this study showed that the capture site had the strongest influence over the feather concentrations of all three metals and the blood concentrations of Pb. In all these, concentrations at the contaminated sites were significantly higher than reference values. Zn in blood showed very different trends, with migratory strategy explaining much more of the variation in the data for blood Zn concentrations, showing that the summer migrants had lower Zn loads. The blood Zn results also showed the Reference site birds having the highest Zn concentrations. Overall, these results suggest that passerines at the TCSFS continue to suffer from heightened levels of heavy metals, especially at locations with closer proximity to chat piles and roads.