The paper describes the objectives, principles and elements of the aquatic environment monitoring system at the mature Arlanskoye oil field. The parameters for the main sources of contamination and changes in the properties and chemistry of fresh surface and subterranean waters are given according to the data from the actual observation system. Based on the analysis of the results the conclusions are drawn as to the efficiency of the implemented measures and procedures and continuous improvement in the quality of the water bodies on the territory of the oil field under discussion.
Key words: monitoring of fresh surface and subterranean waters, contamination of active water cycle zone, water samples, chlorides, oil products, maximum allowable concentration (MAC).
