Evaluation of spatial and temporal changes in biomarker responses in the common carp (Cyprinus carpio L.) for biomonitoring the Meriç Delta, Turkey

The aim of this study is to examine the activity of several biomarkers in carp, Cyprinus carpio L., to determine their response to xenobiotics, such as organochlorine pesticides (OCPs), in the Meriç Delta. Fish were collected from contaminated sites and from areas regarded as relatively less contaminated in four sampling periods. Hepatic glutathione S-transferase (GST), carboxylesterase (CaE), lactate dehydrogenase, aspartate aminotransferase, and acid phosphatase activities were measured as biomarkers in the fish. For all fish, the condition factor and hepatosomatic index, were calculated to determine the condition of the fish. The results of this study indicated that the mean GST activity showed an increase in fish from the Meriç-Ergene junction site and a decrease in Enez site with respect to fish from Meriç site. Furthermore, the study shows that spatial and temporal changes of biomarkers such as GST and CaE might be useful for the assessment of environmental contamination in the Meriç Delta.

► The Meriç Delta is rich in terms of biological resources and is an internationally prominent wetland.
► The aquatic ecosystems in the region have been contaminated by pollutants due to agricultural and industrial activities.
► The effects of seasonal and regional pollution on fish were evaluated in this study.
► The results of this study showed that fish were contaminated by OPCs in the Delta.