Periodic monitoring of persistent organic pollutants and molecular damage in Cyprinus carpio from Büyük Menderes River.

Concentrations of persistent organic pollutants (POPs) were quantified in river water and sediment, as well as in the liver and muscle tissues of Cyprinus carpio that were sampled four times in a year at three stations in the Büyük Menderes River (BMR). Potential biomarkers of possible cellular molecular damage, namely lipid peroxidation (LPO) degradation products, protein carbonyls (PCO) and DNA repair product 8-hydroxy-2'-deoxyguanosine (8-OHdG), were analysed. All the targeted pollutants were measurable both in biotic and abiotic samples. Interestingly, the results suggested that there was recent organochlorine pesticide (OCP) input into the river water in the first two sampling periods in all stations in contrast to prohibition, while input of polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs) was not detected. Liver POP concentrations were higher than in muscle, as expected, and were found to decrease from the first to the fourth sampling period in all stations, except PBDEs. Levels of LPO degradation products in the liver and in muscle tissues decreased from the first to the fourth sampling period. This suggests that these markers reflect the lipid damage in respective tissues due to the tissue burden of targeted POPs. Protein carbonyls were the highest in the first sampling period, followed by a dramatic decrease in the second, and then a gradual increase towards the fourth sampling period in all stations. 8-OHdG levels were lower in Sarayköy station in the first sampling period. Among the measured biomarkers, only several LPO degradation products were significantly correlated with OCPs and PCBs in liver tissue.

Organochlorine pesticides and antioxidant enzymes are inversely correlated with liver enzyme gene expression in Cyprinus carpio.

The present study was designed to investigate the association between levels of organochlorine pesticides (OCPs) and liver enzyme responses in Cyprinus carpio. Fish were caught at three stations in the Büyük Menderes River (BMR): the origin, the Sarayköy station, and the estuary. Seventeen OCPs were quantified in liver tissue, as well as in river water by gas chromatography (GC)-electron capture detection, and structures were confirmed by negative chemical ionization-GC-mass spectrometry. The activities of CYP1A, GST, Se-GPx, CAT, and SODs were determined by spectrophotometry or fluorimetry. The mRNA levels of CYP1A, GST, and SOD1 were quantified by real-time RT-PCR. CYP1A and antioxidant enzyme activities were dramatically higher at the Sarayköy station, where OCP pollution is higher than the other two stations. Mn-SOD is responsible for the increase in total SOD activity in the Sarayköy samples. However, gene expression levels of certain enzymes were heavily suppressed. Our findings show that the transcriptional and functional responses of CYP1A and antioxidant enzymes are inversely correlated.