Fermentation sludge-influence on pesticide transport through soils

The aim of this study was to examine whether digested sludge influences the transport of pesticides which are contained therein through agricultural s oils. It has been reported that organic compounds in soils may slow down or accelerate the transport of organic pollutants. As digested sludge has a h igh content of short-chained dissolved organic carbon (DOC), the work conce rning pesticide transport carried Out to dare cannot be applied. The washin g out of the pesticides ortho-phenylphenol, chlorothalonil, dodemorph, thia bendazole and methidathione from the fermentation sludge was determined in elution experiments at different flow rates. Ortho-phenyl-phenol and methid athione were washed out the fastest, while the remaining compounds were was hed out more slowly. A dependency on the flow rate could only be observed f or ortho-phenyl-phenol. Tn column experiments, the transport of pesticides which are eluted from digested sludge, were compared with the transport of pesticides applied in the usual manner (i.e. they were dissolved in water). Soil-materials from two horizons of a former agricultural area were examin ed No accelerated transport by fermentation sludge was observed. On the con trary, the fermentation sludge seemed to reduce pesticide transport through soil.