Gas-phase polychlorinated biphenyl and hexachlorocyclohexane concentrations near the Great Lakes: a historical perspective.

摘要: The Integrated Atmospheric Deposition Network (IADN) has been measuring gas-phase, polychlorinated biphenyl (PCB) concentrations at sites near Lakes Michigan and Superior for over a decade. Data through 2000 were used in this study to investigate PCB temporal trends the Great atmosphere. Decreasing found both sites, half-lives of approximately 20 yr calculated using IADN data. However, when these data supplemented by historical dating back 1977, dropped 10 6 yr, respectively. These latter agreed well with other environmental compartments. Exponential curves fitted indicated little decline basin since mid-1990s. A similar analysis α- γ-hexachlorocyclohexane (HCH) that best predictor trends, resulting around 4 compounds. γ-HCH concentrations,...