MICROTOX BIOASSAY OF PHOTODEGRADATION PRODUCTS FROM PHOTOCATALYTIC OXIDATION OF PESTICIDES

Abstract

The mineralization of toxicants and the reduction of toxicity were investigated via the photocatalytic reaction. Dichlorvos (an insecticide), 2,4-D (a herbicide) and propoxur (an insecticide) were used as the model compounds in these experiments. Total organic carbon analyzer was used as a measure of mineralization of toxic compounds to assess the efficiency of photocatalytic mineralization. Microtox bioassay was employed in evaluating the toxicity of solutions treated by photocatalysis. The rate of photocatalytic mineralization is more efficient in acidic than in alkaline solution. The degradation pathway and toxicity of pesticides treated in photocatalytic process are pH dependent. Ultraviolet absorption spectra were also used for showing the different characteristics of the compounds undergoing photocatalytic mineralization.