We analysed monthly the concentration of beta-hexachlorocyclohexane (beta-H
CH), a hydrophobic organic contaminant, in aqueous saturation extracts of t
he topsoil from five differently contaminated sites. beta-HCH concentration
in the aqueous soil extract shows a high seasonal variability. Concentrati
ons differ up to 60-fold with peaks up to 2.24 mu g l(-1). Higher beta-HCH
concentrations were found in summer and autumn and accompanied by peaks in
dissolved organic carbon concentration. This indicates the importance of di
ssolved organic matter for beta-HCH mobilization and the risks for groundwa
ter pollution and plant uptake. (C) 1999 Elsevier Science Ltd. All rights r
eserved.