1. Past and current water composition of surface waters in Latvia MĀRIS KĻAVIŅŠ, ILGA KOKORĪTE, VALERY RODINOV University of Latvia

2. Chemical composition of surface waters of Latvia

3. Piper diagram of surface waters of Latvia

4. Long term changes of surface waters

5. Changes of COD and water color

6. Trends of water composition changes accordingly to (1977.-2001.) MANN- KENDALL test Increasing concentrations, p<0,05 Decreasing concentrations, p<0,05

7. Factors influencing water composition? Changes in human loading Changes in landuse Climate change

8. Changes of human loading

9. Impact of landuse un concentrations of nutrients

10. Export of SO 4 2-, kg/km 2 /year

11. Export of nitrates kg/km 2 /year

12. River discharge – major factor controlling concentrations and loading of dissolved substances Gauja - Sigulda (1977.-1997.)

13. River discharge – major factor controlling concentrations and loading of dissolved substances

14. Changes of temperature and precipitation for the Meteorological Station Rīga-University

15. Long term changes of river ice regime

16. Long term changes of river discharge

17. Major large scale atmospheric circulation processes

18. Long term changes of large scale atmospheric circulation processes

19. Deviation of large scale atmospheric circulation processes

20. Long term change of mean annual discharge of the rivers in Baltic region and precipitations. 1 – precipitation (Station Rīga-University); 2 - Nemunas River; 3 - Daugava River; 4 – Narva River; 5 – Parnu River. Data were smoothed with a 6-year moving average.

21. Changes of Venta and Pärnu discharges and index of NAO data were smoothed with a 10-year moving average

22. Long term changes of water runoff and inorganic ion export

23. Factors influencing aquatic chemistry are diverse and they should be considered at the development of monitoring programs

24. Thank you!