Trend of changes in physicochemical state of the river Ner

The paper presents the results of changes in the physicochemical status of the water of the river Ner in the Dąbie profile, observed in the period 2000 – 2006. The river Ner flows through the lowland in central part of Poland and its basin area is 1835 km2. The physicochemical status of the river water was evaluated on the basis of 16 parameters characterizing the physical state, oxygen condition, organic pollution, salinity and acidity. The results of a series of analyses performed over 6 years provided the evidence that the extension of sewage system and enlargement and upgrading of the sewage treatment plant have had positive effect on the state of water in the river Ner. The oxygen conditions have improved and the loading with organic substances from insufficiently purified sewage has decreased. The level of the water salinity has increased.