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| Titel |
In-situ Mass Distribution Quotient (iMDQ) – A New Factor to Compare Bioavailability of Pesticides in Soils? |
| VerfasserIn |
R. Schroll, C. Folberth, H. Scherb, M. Suhadolc, J. C. Munch |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021115
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| Zusammenfassung |
| Aim of this work was the development of a new non-biological factor to determine microbial
in-situ bioavailability of chemicals in soils. Pesticide residues were extracted from ten highly
different agricultural soils that had been incubated with the 14C-herbicide isoproturon (IPU)
under comparable soil conditions (water tension – 15 kPa; soil density 1.3 g cm 3). Two
different pesticide extraction approaches were compared: (i) 14C-Pesticide residues were
measured in the pore water (PW) which was extracted from soil by centrifugation; (ii)
14C-Pesticide residues were extracted from soil samples with an excess of water
(EEW). We introduce the pesticide’s in-situ mass distribution quotient (iMDQ) as a
measure for pesticide bioavailability, which is calculated as a quotient of adsorbed and
dissolved chemical amounts for both approaches (iMDQPW, iMDQEEW). Pesticide
mineralization in soils served as a reference for real microbial availability. A highly
significant correlation between iMDQPW and mineralization showed that pore water
extraction is adequate to assess IPU bioavailability. In contrast, no correlation exists
between IPU mineralization and its extractability from soil with an excess of water.
Therefore, it can be concluded that soil equilibration at comparable conditions and
subsequent pore water extraction is vital for a isoproturon bioavailability ranking of soils. |
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