Characterization of organic contaminants in industrial wastewaters from direct discharges and their behavior in fluvial systems of North Rhine-Westphalia
Intensive anthropogenic exploration of surface waters has lead to the significant contamination of fluvial systems in highly industrialized and densely populated regions. Besides municipal discharges, industrial point sources make substantial contribution to the pollution of river waters emitting a wide range of organic contaminants. Specific character of industrial effluents is represented by high contaminant concentration values and their strong fluctuations, as well as by a wide range of chemical substances because of the high molecular variety of the types of production activities. Their unique appearance within a spatially defined river section receiving wastewater discharge from a particular industrial source allows detection of compounds that can be characteristic for a certain industrial branch or production process. Despite large amount of studies performed on the characterization of industrial effluents from various industrial branches, there is a gap in information on the specificity of contaminants in terms of their molecular structure. At the same time, the detailed study of the distribution and fate of organic pollutants in the surface waters with their attribution to a specific point source is necessary. Based on detailed GC-MS analyses, the molecular diversity of industrial effluents, particularly, from petroleum refinery and oil production, chemical manufacturing, paper and food production sites, and a power station, discharged to the rivers in North Rhine-Westphalia was characterized in order to determine specific industrial markers and so far unknown environmental contaminants. Identification and quantification of potential industrial indicators, which are characteristic for certain industrial branches or production processes, e.g. petroleum and oil production, chemical manufacturing, and paper processing sites), has been performed. A number of environmentally relevant and structurally specific substances were identified. The determination of the distribution of organic constituents within industrial plants is important for the evaluation of a potential anthropogenic impact of industrial discharges resulted from occasional releases of pollutants during industrial accidents. Due to the lack of ecotoxicological data for many wastewater constituents the environmental effects of industrial emissions are often unpredictable. Non-target screening of raw and treated wastewaters allowed the identification of new environmental contaminants that have never been detected in the industrial wastewaters and compounds for which the information on their industrial application and ecotoxicological effects is limited. Monitoring of the environmental distribution of certain environmentally relevant and newly described pollutants in the contaminated river systems allowed the identification of several industrial site-specific markers. The approach proposed in this study goes beyond the scope of the standard environmental regulation procedures and is important for efficient source identification in polluted aquatic systems and better evaluation of possible environmental impact of anthropogenic emissions
