A 90-YEAR RECORD OF WATER-QUALITY DATA OF PARIS SEINE AND MARNE RIVERS

The water quality monitoring data on the Seine-Normandy basin between 1910 and 1993 are presented. Temporal and spatial variability were exa mined for six parameters: ammonium, nitrates, chlorides, dissolved oxy gen, biological oxygen demand and total coliforms? in 22 stations spre ad over the Seine and the Marne rivers. The water quality parameters w ere significantly altered from 1950 onwards, except for ammonium which has been present since the beginning of the century in the lower cour se of the River Seine. Despite all efforts, especially those focused o n sewage treatment plant construction and enlargement, the Rivers Sein e and Marne have not recovered the level of water quality of the forme r century.