Abstract:
Chlorpyrifos (CPF) is a member of the group of organophosphate pesticides (OPPs) used extensively for agricultural pest control throughout the world. CPF as a consequence of agricultural runoff enter into water bodies and deteriorate their quality as well as interfere with aquatic ecosystems. Fish have been widely used as biomonitor for environmental pollutants. In current study common carp (Cyprinus carpio) was chosen as a model organism to evaluate the effects of chlorpyrifos on immuno-hematology, oxidative stress and to monitor residues levels in muscle tissues. Acute toxicity tests showed 24, 48, 72 and 96h-LD50 of CPF for common carp in semi static tanks were 1.53, 1.16, 0.90 and 0.67 mg/L respectively. Sub-acute toxicity test was performed by exposing organism with sublethal concentration (134, 13.4, 1.34 μg/L which corresponds to 1/5, 1/50, 1/500 of the 96h-LD50) of chlorpyrifos for 7 and 14 days. Spectrophotometric nitroblue tetrazolium (NBT) reduction assay showed that respiratory burst activity decreased as a function of CPF dose and exposure time ultimately lead to reduction in immunity. Spectrofluorometric analysis revealed significant augmentation in ROS production in brain and gills of exposed fish by increasing concentration and exposure duration of CPF, which may cause oxidative stress. GC-ECD analysis indicated 60, 68 and 70% accumulated amounts of CPF residues in muscle tissues when exposed with sub-lethal concentrations (134, 13.4, 1.34 μg/L) for 30 days.
