The behaviour of the anionic surfactant Linear Alkylbenzene Sulphonates (LAS) in sandy soils with weak sorption capacities was investigated in a field trial and lysimeter studies. LAS were mobile in the investigated four different soils. LAS could be detected down to a depth of 35 cm. In the course of moving through the soil column, the homologues with longer alkyl chains were retained more strongly than the short chain homologues. In these studies, the LAS were rapidly biodegraded. The resulting half-lives were between 3 days in the lysimeters and 7 days in the field trial study during a vegetation period, respectively. An accumulation of LAS at a certain depth was not observed. (C) 1997 Elsevier Science Ltd.