Distribution and persistence of DDT in soil at a sand dune-marsh environment: Point Pelee, Ontario, Canada

Abstract

Crowe, A. S. and Smith, J. E. 2007. Distribution and persistence of DDT in soil at a sand dune-marsh environment: Point Pelee, Ontario, Canada. Can. J. Soil Sci. 87: 315-327. DDT was applied at Point Pelee, Ontario, Canada, between 1948 and1970 for mosquito control in recreational areas and pest control in former agricultural areas. Recent soil sampling programs produced 275 analyses enabling a statistical comparison of DDT concentrations with land use areas, soil conditions, and hydrologic characteristics. Concentrations of ΣDDT ranged over several orders of magnitude, with the highest concentrations (maximum 316 000 ng g -1 ) in former agricultural areas and the lowest concentrations in the natural sand dunes (maximum of 116 ng g -1 ). DDT is undergoing degradation at Point Pelee along two pathways. DDT is transformed aerobically to DDE within the sandy soils exhibiting average %DDT, %DDE and %DDD of 40%, 55%, and 5% of ΣDDT, respectively. DDT is transformed anaerobically to DDD and DDE within the marsh and flooded soils averaging 14% DDT, 44% DDE, and 42% DDD, respectively. The half-lives for the transformation of DDT to DDE within the well-drained and aerobic sandy soils at Point Pelee are highly variable and were estimated to range from 20 to 50 yr. Given the high concentrations of ΣDDT at Point Pelee and the long half-life, it is expected that DDT will remain at concentrations of concern for many decades. , on a appliqué du DDT à la pointe Pelée, une région de l'Ontario (Canada), pour lutter contre les moustiques dans les aires récréatives et pour combattre les parasites dans les anciennes zones agricoles. De récents programmes d'échantillonnage du sol ont permis 275 analyses qui devaient servir à comparer la concentration de DDT selon la vocation des terres, l'état du sol et l'hydrologie. La concentration de ΣDDT varie de plusieurs ordres de grandeur, la plus élevée (maximum de 316 000 ng/g) ayant été observée dans les vieilles zones agricoles et la plus faible, dans les dunes de sable naturelles (maximum de 116 ng/g). À la pointe Pelée, le DDT se dégrade de deux façons. Il se transforme de manière aérobie en DDE dans les sols sablonneux, avec une moyenne pour le DDT, le DDE et le DDD de 40 %, 55 % et 5 % du ΣDDT, respectivement, et de manière anaérobie en DDD et DDE dans les marais et les sols inondés avec une moyenne de 14 % de DDT, de 44 % de DDE et de 42 % de DDD, respectivement. La demi-vie nécessaire à la transformation du DDT en DDE dans les sols bien drainés et sablonneux aérobies de la pointe Pelée varie considérablement, avec une fourchette estimative de 20 à 50 ans. Étant donné la forte concentration de ΣDDT à la pointe Pelée et la longue demi-vie du DDT, on s'attend à ce que la concentration de ce pesticide demeure problématique pendant de nombreuses décennies encore.

Examination of temporal DDT trends in Lake Erie fish communities using dynamic linear modeling

“…Notably, DDE has been found to be more persistent than its parent compound, lingering in the environment for decades after the cessation of DDT input (Boul, 1995;Thomas et al, 2008). Both metabolites have been observed in soils within the Lake Erie region, with a Point Pelee analysis revealing high proportions of DDE in sandy soils (Crowe and Smith, 2007), while the Winous Point marshes to the south of the lake mainly contained the reduced DDD metabolite (Spongberg et al, 2004). The continued presence of DDT-associated compounds in soils is a function of their long half-lives as well as their strong absorption to soil particles; DDT and its metabolites generally remain within the top soil layers and are thus susceptible to runoff into waterbodies (ATSDR, 2002).…”

“…Specifically, the late summer anaerobic conditions in the lake hypolimnion are favorable for DDD production, whereas the fall turnover and the reoxygenation of the water column result in a combination of aerobic and anaerobic conditions that are optimal for further DDD decomposition (DeVault et al, 1988). Recent studies have shown elevated DDD concentrations in two marshes surrounding Lake Erie (Crowe and Smith, 2007;Spongberg et al, 2004) and levels in local mussels were also measured to be relatively high (Robertson and Lauenstein, 1998). Clearly, the various morphological and ecological lake characteristics can alter the ratios of DDT and its metabolites within the water, sediment and biota, and thus careful analyses of different pollutant congeners may be essential tools in freshwater remediation.…”

Phytoextraction of DDT-Contaminated Soil at Point Pelee National Park, Leamington, ON, Using Cucurbita pepo Cultivar Howden and Native Grass Species

“…Point Pelee National Park is located in Leamington, ON, Canada, and consists of a peninsula of land (16 km 2 ) made up of marsh and woodland habitats. It is ecologically important due to its support of significant bird and butterfly migrations and breeding habitats (Crowe and Smith, 2007). For this study, three sites were selected on the basis of their mean ΣDDT soil concentration.…”

“…1,1,1‐trichloro‐2,2‐bis(4‐chlorophenyl)ethane (dichlorodiphenyltrichloroethane [DDT]) and its metabolites 1,1‐ bis ‐(4‐chlorophenyl)‐2,2‐dichloroethene (dichlorodiphenyldichloroethylene [DDE]) and 1‐chloro‐4‐[2,2‐dichloro‐1‐(4‐chlorophenyl)ethyl]benzene (dichlorodiphenyldichloroethane [DDD]), collectively referred to as ΣDDT throughout this paper, are POPs that have had major environmental impacts as a result of ΣDDT's widespread use as an insecticide (Ritter et al, 1995). The persistence of ΣDDT is indicated by its half‐life, which ranges from 2 to 35 yr (ATSDR, 2002; Crowe and Smith, 2007; White, 2010). In addition, as ΣDDT has a high hydrophobicity with an octanol‐water partition coefficient (log K ow ) > 6, it binds strongly to organic matter in the soil (Alexander, 2000; Wang et al, 2004; White et al, 2005).…”

“…In 2007, Crowe and Smith conducted a comprehensive study of ΣDDT in the soil and sediments of PPNP. A maximum soil ΣDDT concentration of 316,000 ng/g was identified in an area referred to as former agricultural land (Crowe and Smith, 2007). This level far exceeds the Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health of 700 ng/g ΣDDT in areas designated as residential or parkland (CCME, 1999).…”