Abstract niet beschikbaarAn in situ experiment using an injection/withdrawal system was done with five pesticides (atrazine, 1,3-dichloropropene, dinoseb, mecoprop and propachlor) at a location in Schaijk. Pesticides and a tracer (chloride) were injected at 7 m below surface and withdrawn again at the same depth 1.5 m downstreams. Sorption of pesticides was found to be of little importance: only atrazine showed retardation by a factor of 1.3 three pesticides (1,3-dichloropropene, dinoseb and propachlor) disappeared from the system ; their halflife times were 10 d, 1.3 d and 20 d respectively. Mecoprop showed no reaction at all. The computercode PULS which was developed for the interpretation of in situ experiments proved to be appropriate for approximating sorption and tranformation constants both for the in situ experiment in Schaijk and for experiments performed earlier. With the simulation package METROPOL a good agreement was found between measured and calculated breakthrough curves.EG/DG12-Bodemkwalitei
