Mobility of dichlorprop in the soil-water system as a function of different environmental factors. I. A batch...

Batch experiments were conducted to study the mobility of 14C-labelled dichlorprop in different soil types. Soils rich in organic carbon showed high sorption capacity compared to sand soil with low content of organic C. Soil to soil variations decreased when corrected for different content of organic C (Kd normalized to Koc). Data obtained in batch experiments fit into linear as well as Freundlich sorption isotherms (17 degrees C). Desorption of [14C]dichlorprop in the soil-water system increased with pH. A significant amount of dichlorprop may be considered as 'non-available' in soils with high organic C, even at relatively high pH-values. The octanol/water partitioning coefficient (Kow) for dichlorprop was inversely related to pH. In the pH range 4-7, the Kow-value varied from 114 to 0.6. The relationship between Koc and pH was similar to the relationship between Kow and pH and the data fitted the following equation: log Koc = 0.5 log Kow + 0.2 (r2 = 0.986).