Due to intensive urban, industrial and agricultural activities, surface water resources are at risk of severe pollution. Specific pollutants are defined by Water Framework Directive as the pollutants those are discharged to the water resources in significant amounts. These pollutants have various adverse effects on the aquatic organisms and humans exposed to them through different pathways. Identification and control of specific pollutants is an obligation under Water Framework Directive (2000/60/EC), in order to reach “good water quality” in all waters and ensure healthy water environment for different use alternatives. Control of specific pollutants in surface waters are ensured by the implementation of their environmental quality standards (EQS), concentrations in water, sediment or biota which should not be exceeded in order to protect human health and the environment.
As a candidate for EU membership, Turkey, has conducted comprehensive studies to determine the river basin specific pollutants and deriving environmental quality standards for these pollutants. Within the scope of these studies, point and diffuse pollutant sources were identified and pollutants that would be discharged by these sources were specified. Specific pollutants identified by other EU countries and pollutants listed in international agreements were also considered and all those chemicals were listed as “universe of chemicals”.
Following the constitution of initial chemicals list, COMMPS method was used to determine the final specific pollutants list. By this method, chemicals were ranked according to their usage amount, physicochemical properties, toxicity, potential to be present in wastewater, and environmental fate. In addition to this, two simple methods were also used to rank the chemicals for which usage data was not available. Moreover, monitoring studies were carried out to detect the levels of these pollutants in receiving water bodies and wastewater discharges. The outputs of the 3 methods and monitoring studies were combined and 117 point-sourced and 133 diffuse-sourced specific pollutants were assigned.
In order to derive the environmental quality standards for specific pollutants, acute and chronic toxicity data was collected from the literature and assessed statistically. The level which is safe for 95 % of the population was selected as the environmental quality standard generally.
The specific pollutants and the corresponding environmental quality standards were incorporated into By-Law on Surface Water Quality Management. According to the provisions of the by-law, environmental quality standards for specific pollutants must be met by the end of 2019. Therefore, monitoring programs including specific pollutants have been prepared for 25 river basins. Currently, efforts are put to reveal the measures to achieve the environmental quality standards. The study is an outstanding example of bridging science and policy in water quality management since it directly makes use of the outcomes of scientific studies in policy making.