Causes of Variability in Pesticide and PCB Concentrations in Air near the Great Lakes

Abstract

Data through 2001 from the Integrated Atmospheric Deposition Network (IADN) were used to investigate the causes of variability in gas-phase polychlorinated biphenyl (PCB) and pesticide concentrations measured near Lakes Michigan, Erie, and Superior. A multiple linear regression model that incorporates temperature and time was used explain the variability in the concentrations. Our approach used autocorrelation analyses of the residuals to help us determine the effectiveness of the regression. Autocorrelation plots forthe in-use pesticide lindane indicated that an agricultural application cycle was also present in the regression residual data at all sites. The addition of parameters for this effect to the regression equation accounted for, on average, 16% more of the variability in the data. Similar analyses forthe in-use pesticide endosulfan did not show an agricultural application effect. The banned compounds DDT and chlordane showed that temperature and time correctly accounted for the variability in the atmospheric concentrations of these compounds at all sites. In contrast to the other compounds, PCBs and hexachlorobenzene showed strong residual autocorrelation patterns near Lake Michigan of an unknown origin.

Temporal and Spatial Trends of Organochlorine Pesticides in Great Lakes Precipitation

“…The calculated dates on which the pesticide concentrations in precipitation maximize at each of the IADN sites are listed in Tables S2-S8. Concentrations of endosulfan and γ-HCH, which are still in use, usually peaked in June or July, a time which corresponds well with their maximum agricultural usage (35,36). The use of all the other pesticides is restricted in the U.S., with the exception of methoxychlor, which is still being used in agriculture and on livestock.…”

The Lake Michigan contaminant transport and fate model, LM2-toxic: Development, overview, and application

“…The variation of the estimated rates of decline for atmospheric components (dry and wet deposition, and vapor-phase concentration) was quite large with half-lives ranging from 6 to 20 years. It appears that the rate of decline decreased with the addition of more recent data (Buehler et al, 2004, Hillery et al, 1997, Hornbuckle et al, 2006, Schneider et al, 2001, Simcik et al, 1999. The purpose of the Scenario B and C forecasts was to provide boundaries for predicted long-term PCB water column concentrations by assuming a six-year and 20-year half-lives for PCB atmospheric components, respectively.…”

Assessing the effects of urbanization on the environment with soil legacy and current-use insecticides: A case study in the Pearl River Delta, China

“…Meijer et al (2001) found that the half-life time of p,p′-DDT in Luddington soils of the United Kingdom is 11.8 years, which is longer than those (8.2 ± 1.4 and 7.1 ± 1.0 years, respectively) in the atmosphere of Sleeping Bear Dunes and Sturgeon Points around the Great Lakes (Buehler et al, 2004). Hence, it is speculated that p,p′-DDT would degrade into p,p′-DDD faster in air than in soil, making soil a secondary source of p,p′-DDT and a sink of atmospheric p,p′-DDD.…”