Enantioselective degradation of organochlorine pesticides in background soils: variability in field and laboratory studies.
Variability in the enantioselective degradation of chiral organochlorine pesticides (alpha-HCH, cis- and trans-chlordane (CC and TC), and o,p'-DDT) in the field and laboratory was investigated. Background soils presumably receive the same EF signature of a compound via atmospheric deposition and then degrade that compound in a way that can vary over small spatial areas. Background soils from woodland and grassland areas were sampled to compare chiral signatures and determine the spatial variability within a few square meters. The enantiomer fractions, EF = areas of the (+)/[(+)+(-)]-enantiomers, showed variability between and within ecosystems. For example, the EF of CC varied between 0.272 -and 0.558 in nine samples taken over a few square meters, and a range of 0.431-0.506 was found within depths of a few centimeters. Woodland and grassland soils were spiked with alpha-HCH, TC, CC, and o,p'-DDT, and one portion was placed in the field to monitor changes in EF under in situ conditions and the other taken to the laboratory. In general, the enantiomer degradation preferences in the laboratory paralleled those in the field, with some differences. Soil organic matter content and pH exerted a minor influence on this variability. The results of this study have implications for the use of chiral compounds to make inferences about air-soil exchange and for the mechanisms of biodegradation/ biotransformation of anthropogenic compounds in soils.
Kurt-Karakus
Perihan Binnur
PB
Centre for Atmospheric Research Experiments, Science and Technology Branch, Environment Canada, 6248 Eighth Line, Egbert, Ontario L0L 1N0, Canada
Stroud
Jacqueline L
JL
Bidleman
Terry
T
Semple
Kirk T
KT
Jantunen
Liisa
L
Jones
Kevin C
KC
D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry*; D012989:Soil Pollutants; D013237:Stereoisomerism
D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D012989:Soil Pollutants