Rates of Sorption and Partitioning of Contaminants in River Biofilm

Abstract

Biofilms are believed to play a significant role in the fate and transport of contaminants in aquatic environments. However little is known about the rates of sorption (k) and partitioning (Kd) of contaminants to biofilms. Studies of the latter were performed using mature biofilm cultivated in a roto-torque reactor. The reactor was flushed with river water containing a mixture of tetrabutyltin, p,p-DDT, diclofop-methyl, triallate, lindane, atrazine, parathion-methyl, and dimethoate in two experiments. The first experiment was conducted at a spiked level of 1 μg/L, and the second was conducted at 10 μg/L for each component. Apart from dimethoate, there was rapid depletion of all contaminants from the water phase within the first 5−10 min with sorption occurring by pseudo-first-order kinetics. In general, the mean values of k (10-4 min-1) increased with water solubility and were 8, 70, 110, 180, 230, 370, and 100 for p,p-DDT, diclofop-methyl, triallate, tetrabutyltin, lindane, atrazine, and parathion-methyl...