OCCURRENCE AND BEHAVIOR OF SELECTED HERBICIDES IN SOILS OF THE EAST-GERMAN DRY ZONE

Triazine residues were detected in about 50 % of all soil horizons and in > 70 % of Ap-horizons of investigated agricultural areas of the Sa ale county. Within soils situated on slopes, lateral matrix flow throu gh may be a mechanism of decontamination, connected with an additional burden of accumulating zones downslope. Depending on the situation of historic immission, 66 % of Ap-horizons under conventional agricultur al practice contain triazine residues mostly < 30 mu g kg(-1). In the respective subsoils, this contamination decreases to 23 %. Sites with a high historical potential for input (orchards, herbicide storages) a re contaminated at 89 % at their surfaces and 78 % of the subsoils. Ty pical concentrations in these Ap-horizons vary from 30 mu g kg(-1) to 100 mu g kg(-1) (herbicides storages often > 100 mu g kg(-1)), the res pective parent rock (typically loess) ranging from 10 mu g kg(-1) to 3 0 mu g kg(-1). The soils are contaminated above average, also their de eper horizons. Presumably, the reason for this is a prolonged persiste nce of the herbicides caused by the local semiarid climate.