Evaluation of the water quality status of two surface water reservoirs in a Mediterranean island.

A 1-year monitoring study is presented on the chemical status of two surface water reservoirs in a decentralized Mediterranean island. Water samples were collected at varying depths in the two surface water reservoirs and different seasons between November 2015 and September 2016, covering both wet and dry periods of the year. Samples were analyzed in order to determine major chemical parameters and priority substances based on the EU Water Framework Directive (2000/60/EC) and the latest revision of the Priority Substances Policy Directive (2013/39/EU). Tested parameters in both reservoirs did not exceed the set limits. Increased pollutant concentrations were observed in the bottom samples. More than 200 pesticide active substances were determined but none of them was above the parametric trigger value (0.1 μg L-1). Toxic metals were not detected in the examined water samples, whereas the relatively high concentrations of Mn and Cu in the bottom samples are mainly attributed to geogenic background concentrations. Based on the results of the present study, it can be concluded that the chemical situation of both water reservoirs is considered acceptable; however, continuous monitoring should be implemented in the area.