Seasonal impacts on beta-hexachlorocyclohexane concentration in soil solution

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.