Abstract:
Abstract Pesticides have many different properties that affect their behaviour in the environment. Pesticide’s solubility
in water has a great impact on leaching potential and environmental fate. The objective of this study was to determine the
relationship between organic carbon based partition coefficient (k oc ) and pesticides solubility (S) of pesticides used along the
shore of Lake Naivasha using regression analysis. The properties (S, and soil/water equilibrium partition coefficient (kd)) of
pesticides selected from an inventory of pesticides used in farms around Lake Naivasha, were determined from the
manufacturers’ materials safety data sheets. The organic carbon (f oc ) of the soil from the study area was then determined using
the loss-on-ignition (LOI) method and used to calculate k oc. The results showed that the soils around Lake Naivasha had a
mean organic carbon (f oc ) content of 1.770% and a regression equation for k oc and S for the area to be log koc = -0.368logS +
3.256. It was concluded that this relationship can be used to estimate the organic carbon based partition coefficient (k oc) of a
pesticide where S is available, and the results compared with values determined experimentally and from other models.
