Water quality in rivers is of major importance for the quality of the aquatic ecosystem. While major rivers in the western part of Europe have been intensively studied, only little data is available for the region of the former eastern countries. Within the scope of a Russian/German co-operation project "Development and application of a sampling and characterisation concept for the determination of the water quality of river systems - spatial and temporal variability of the water quality of river Oka by inputs of river Moskva at Kolomna", water quality of the rivers Oka and Moskva is being investigated in the mouth region at Kolomna in Russia. River Oka is a major tributary of river Wolga draining an area of about 73700 km². Annual discharge into river wolga is about 10 billion m³. River Moskva is a major tributary of river Oka that drains the Moscow region, an area of extensive industrial activity and high density of population. The research project is a co-operation of the all-Russian Research Institute of Hydraulic Engineering and Land Reclamation in Moscow and the Division of Water Chemistry of the DVGW Research Site at the Engler-Bunte-Institute in Karlsruhe.
The goal is the development and application of a sampling and characterisation concept for the determination of water quality in river systems. Between 1996 and 1999 mor than 300 samples from selected sample sites have been analysed for pH, conductivity, TOC, DOC, AOX, CSB, ammonia, nitrite, nitrate, phosphate and sulphate. Samples were taken weekly and have been analysed in a laboratory in Kolomna. Mixed samples were shipped monthly to Karlsruhe for additional analysis of organic pollutants and heavy metals.