Pesticides in the surface waters of Lake Vistonis Basin, Greece: Occurrence and environmental risk assessment

Abstract A study was undertaken for the evaluation of the pesticide pollution caused by the agricultural activities in the basin of Lake Vistonis, Greece during the years 2010–2012. Water samples were collected from Lake Vistonis, four major rivers and various small streams and agriculture drainage canals. The concentration of 302 compounds was determined after solid-phase extraction of the water samples and subsequent LC-MS/MS and GC-MS/MS analysis of the extracts. Overall, herbicides were the most frequently detected pesticides (57%), followed by insecticides (28%) and fungicides (14%). In Lake Vistonis 11 pesticides were detected. Specifically, fluometuron was detected in the 75% of the samples (maximum concentration 0.088 μg/L) whereas lambda–cyhalothrin was detected in all the samples of spring 2011 and alphamethrin in all the samples of spring 2012 (maximum concentration 0.041 and 0.168 μg/L, respectively). In the rivers and drainage canals 68 pesticides were detected. Specifically, fluometuron was detected in the 53% of the samples (maximum concentration 317.6 μg/L) followed by chlorpyrifos and prometryn (16 and 13% of the samples respectively). An environmental risk assessment was performed by employing the Risk Quotient (RQ) method. The risk assessment revealed that at least one pesticide concentration led to a RQ > 1 in 20% of the samples. In Lake Vistonis, alphamethrin and lambda–cyhalothrin concentrations resulted in RQ > 1, whereas in the other water bodies this was mainly the result of chlorpyrifos–methyl and alphamethrin exposure. In contrast, herbicide and fungicide concentrations contributed substantially less to environmental risks.