Seasonal impacts on β-hexachlorocyclohexane concentration in soil solution

We analysed monthly the concentration of β-hexachlorocyclohexane (β-HCH), a hydrophobic organic contaminant, in aqueous saturation extracts of the topsoil from five differently contaminated sites. β-HCH concentration in the aqueous soil extract shows a high seasonal variability. Concentrations differ up to 60-fold with peaks up to 2.24 μg l−1. Higher β-HCH concentrations were found in summer and autumn and accompanied by peaks in dissolved organic carbon concentration. This indicates the importance of dissolved organic matter for β-HCH mobilization and the risks for groundwater pollution and plant uptake.