Photocatalytic Degradation of 2, 4-D and Transition of Endocrine Disruptive Activity Using Transcriptome Based Bioassay in Zebrafish Embryos

Abstract

2, 4-Dichlorophenoxyacetic acid (2, 4-D) is one of the most widely used halogenated agricultural chemicals around the world and a well known endocrine disrupting chemical (EDC). TiO2 based photocatalytic degradation of 2, 4-D was carried out and residual endocrine disruptive (ED) activity was determined by an in vivo model of zebrafish embryos exposed to various concentrations of 2, 4-D and its degraded products from 5 hpf (hours post fertilization) to 72 hpf. Quantitative Real Time PCR was carried out to determine the relative expression of Heat shock protein (HSP70) and Glutathione peroxidase (GPX) genes of zebrafish using ß-actin as housekeeping gene. HSP 70 expression increased at 150 μg/L 2, 4-D concentration while the expression was significantly lowered after its photocatalytic degradation. GPX expression was not significantly altered. The results reveal the validity of HSP gene affected by 2, 4-D exposure and some probability of toxic potential of byproducts formed during its degradation