Temporal and latitudinal trends of p,p′‐DDE in eggs and carcasses of North American birds from 1980 to 2005

The use of 1,1,1‐trichloro‐2,2‐bis(p‐chlorophenyl) ethane (DDT) in agriculture in the United States and Canada was prohibited in the early 1970s; however, it continued to be used restrictively in Mexico until 2000. Forty years later, 1,1‐dichloro‐2,2‐bis(p‐chlorophenyl) ethylene (p,p′‐DDE), continues to be detected in eggs and bird carcasses in North America. The use of DDE has been associated with reproductive failure of several avian species, primarily through eggshell thinning. To assess the temporal and latitudinal distribution of p,p′‐DDE in North America, the authors examined DDE concentrations reported in bird tissues in the scientific literature published between 1980 and 2009. Overall, the majority of supported models suggested that DDE concentrations in birds were greater in the upper mid‐latitudes (38°–48°) than in other parts of North America. However, spatial trends of DDE seemed to be influenced by regions with large amounts of data, such as the Great Lakes area. Concentrations of p,p′‐DDE in eggs averaged 2.5 μg/g, 3.2 μg/g, and 29.5 μg/g wet weight in 1980 and decreased to 1.64 μg/g, 0.87 μg/g, and 1.01 μg/g wet weight by the mid‐2000s for the central, eastern, and western North America regions, respectively. The results indicate that, over time, all DDE residues observed in birds have decreased significantly in North America. Environ Toxicol Chem 2016;35:1340–1348. © 2016 SETAC