A method of calculating the pesticide partition between sediment and water for environmental systems

Abstract

Pesticide values were calculated for natural systems in which the pesticides were partitioned between sediments and water. Two equations were evaluated that correlate the variables, surface area, pesticide concentration on the sediment and pesticide concentration in the water. The first, a linear equation, proved sufficiently accurate to calculate 45 or 48 data points to within one order of magnitude of the observed values. The second, a 7th degree polynominal was used on the same data set and resulted in a calculation of 46 of 48 values within one order of magnitude. Comparisons as to percent accuracy within the order of magnitude agreement revealed the linear equation was capable of reproducing the observed values to within 10 percent for 39 percent of the data set tested, and the 7th degree polynominal was capable of achieving this accuracy for 52 percent of the same data set. The correlation of surface area with pesticide partitioning illustrates the use of a readily measurable parameter (surface area) and pesticide concentration in the sediment to allow calculation of a non-measurable parameter (pesticide concentration in water). The utility of this work is an approximate calculation of pesticides in water at concentration ranges below the measurable limits of present day analytical equipment.