WATER QUALITY CHANGES IN LATVIA IN RELATION TO CHANGING LOADING LEVELS
Long-term changes of the chemical composition and biological quality of Lacvian inland waters have been evaluated. Water composition, the major factors influendng water chemistry, and the human impacts were studied to determine the changes after recent reductions ofpollution emissions, particularly nurrient loading, to surface waters. The chemical composition much depends on hydrological factors, which differs between eastern and wesrern Latvia. Temporal fluctuations are superimposed on this variability. Different patterns of long-term changes were observed for substances having different sources and sinks. Organic matter and inorganic ingredients generally showed a decreasing trend.