| Autor: |
Mehmetli, Ebru, Koumanova, Bogdana, Kurt-Karakus, Perihan B., Bidleman, Terry F., Jones, Kevin C., Meijer, Sandra N., Staebler, Ralf M. |
| Zdroj: |
Fate of Persistent Organic Pollutants in the Environment; 2007, p315-331, 17p |
| Abstrakt: |
Background soils (̃230 samples) were analyzed for DDT and its derivatives to determine the distribution of these compounds on a global scale. Total concentrations of DDT and its metabolites (∑DDTs) ranged over four orders of magnitude, from <0.01 to 426 ng g−1 dry weight and correlated poorly with soil organic matter content (SOM%) and latitude. The average composition of soil residues was similar in the Northern and Southern hemispheres and followed the order: DDT > DDE > DDD. The fraction FDDTe = p, p′-DDT/(p,p′-DDE + p,p′-DDE) averaged 0.60 ± 0.30, or an average p,p′-DDT/p,p′-DDE ratio of 1.5. Soil-to-air fluxes of DDT compounds were measured at an experimental farm in Ontario, Canada, where DDT was last applied more than three decades ago. Results showed that agricultural soils are still a significant source for emission of DDTs to the atmosphere. DDT compound ratios in air can be used to distinguish fresh applications from soil emissions, but fractionation of the DDTs occurs during volatilization. The ratio of p,p′-DDT/p,p′-DDE in air over soil can be predicted from soil residues, assuming that their volatilities are in a direct relation to liquid-phase vapor pressure (PL). Results at the Ontario farm and at other farms in Canada and the USA where soil—air exchange studies have been done showed that PL was a better predictor for FDDTe than KOA. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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