THE INFLUENCE OF SURFACTANTS APPLIED BY SEWAGE-SLUDGE ON THE BEHAVIOROF ATRAZINE AND PAHS IN SEMIARID SOILS

The effect of two surfactants applied via sewage sludge: LAS (linear A lkylbenzenesulfonate) and Nonylphenol as a metabolite of Nonylphenol e thoxylate, on PAHs and Atrazine mobility was investigated under semiar id soil conditions in a Vertisol and a Gypsisol treated with sewage sl udge.In both cases the surfactants promoted the leachability of Atrazi ne only moderately compared to the untreated plot. PAHs were leached f rom the surface Layer (0-20 cm) into 20-50 cm layer during the three m onth test period. Relatively higher leaching was observed in the sandy Gypsisol. Atrazine was leached only in the clay Vertisol where the su rfactants were present longer than io the plot with sandy Gypsisol.