Fate of dichlobenil in the River Ivel. 2: Effects of dichlobenil residues on hydroponically grown lettuce

Abstract

Following claims that dichlobenil in river water had caused damage to lettuce (Lactuca sativa) in 1995, a series of trials were carried out to assess the effects of dichlobenil on lettuce grown using hydroponic techniques under glass. Plants grown in three inch pots of soil-based compost and watered with dichlobenil solution at concentrations up to 300 000 ng/l showed no differences in growth compared to the untreated controls. Plants grown in peat-based compost in a static nutrient solution showed a phytotoxic reaction when dichlobenil concentrations reached 100 000 ng/l or greater. Trials on plants grown using a dynamic nutrient film technique indicated that under glasshouse conditions, dichlobenil solutions as low as 10 ng/l could adversley affect the development of lettuce plants.