Time series analysis on chlorides, nitrates, ammonium and dissolved oxygen concentrations in the Seine river near Paris.

Graphical and statistical time series techniques have been used to analyze the trends and specified time changes, in a 90-year record of annual average value of Seine river water quality data. The information obtained may be associated with some socio-economic variables, such as industrial or agricultural development, urban increase and wastewater discharge around or upstream of the measure station. Such a study may now be applied to more rural stations in order to compare the evolution of water quality and, perhaps, historical monthly average values to evaluate the seasonality effect on annual trends.