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| Titel |
Soil-Air exchange controls on background atmospheric concentrations of organochlorine pesticides |
| VerfasserIn |
A. Cabrerizo, J. Dachs, K. C. Jones, D. Barceló |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 24 ; Nr. 11, no. 24 (2011-12-19), S.12799-12811 |
| Datensatznummer |
250010279
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| Publikation (Nr.) |
 copernicus.org/acp-11-12799-2011.pdf |
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| Zusammenfassung |
| Soils are the major terrestrial reservoir of persistent
organic pollutants, and thus net volatilization from soil, when it happens,
may exert a control on the atmospheric occurrence and variability of organic
pollutants. Here, we report and discuss the concentrations of legacy
organochlorine pesticides (OCPs) such as hexachlorobenzene (HCB),
hexaclorocyclohexanes (HCH) and dichlorodiphenyltrichloroethane (DDT) in the
atmosphere and in soils, their measured fugacities in soil, the soil-air
partition coefficients (KSA) and soil-air fugacity ratios
(fs/fa) in rural background areas of N-NE Spain and N-NW England.
Four sampling campaigns were carried out in Spain and UK to assess seasonal
variability and differences between sampling sites. KSA values were
significantly dependent on soil temperature and soil organic matter
quantity, and to a minor extent on organic matter type. HCH isomers and DDT
metabolites in soil are close to equilibrium with the overlying atmosphere
at rural background areas of Spain with a tendency to volatilize and deposit
during warm and cold periods, respectively. The mixture of HCH and DDT found
in the atmosphere is clearly strongly influenced by the mixture of HCH and
DDT which escapes from soil, with significant correlations between them
(r2 ranging between 0.63–0.76 and p-level<0.001 for the Ebro sampling
sites), thus suggesting a close coupling of air and soil concentrations,
demonstrating that net volatilization from soil control the atmospheric
levels of OCPs in the Northern Spain background atmosphere. Conversely,
soils at rural UK sites were usually a sink for atmospheric DDT and HCH, but
not for HCB. The negative statistically significant relationship found
between log KSA and the log (fs/fa) ratio, suggests that high
latitude regions, due to the high soil organic matter content and lower
temperatures, will act as larger traps and accumulate more atmospheric OCPs.
Thus, the extent to which soils are secondary sources to the atmosphere is
currently dependent on the reservoir potential of soils for OCPs and shows a
marked seasonality in their strength. |
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