Residual dichlorodiphenyltrichloroethane distribution in the soils and sediments of Point Pelee National Park: Implications and tools for remediation
2016
Clow, Rachel | Rutter, Allison | Zeeb, Barbara A.
Point Pelee National Park (PPNP), located in Leamington, ON, is heavily contaminated with the pesticide dichlorodiphenyltrichloroethane (DDT) that was liberally used for mosquito and pest control in the park from the 1940s until the 1960s. This study was designed to update and enhance information that will advise PPNP personnel on remediation strategies. Building on previous research, a comprehensive soil and sediment sampling, and analytical program was carried out over several years and was completed in 2014. In total, 140 soil, nine sediment, and four water samples were analyzed by gas chromatography/electron capture detection. Dichlorodiphenyltrichloroethane contamination boundaries were defined, and they were determined that this contaminant occurs predominantly in three “hot spot” areas with total DDT levels exceeding 130 000 ng g⁻¹, which is 19 000% higher than federal guidelines. This information was mapped into an interactive Google Earth platform. Dichlorodiphenyltrichloroethane isomer analysis compared groupings of samples and determined that soil hot spot areas have half-lives ranging from 27 to 40 yr. It was determined that the highest concentrations of DDT (not including DDT’s derivatives) could remain above federal guidelines for a further 220–342 yr. Overall this study improved delineation of DDT hot spots and narrowed the half-life ranges of DDT and its metabolites in PPNP.
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