Nitrates are natural components of the surface water, the amounts in surface waters is very important, usually being insignificant, but in urban area and along agricultural areas situated inside the river basin, their concentration is increased, being non-point sources and point sources located in the city. The nitrate concentrations is influenced both by the seasonal changes of rainfall and temperature as well as by land-use transformations, the variation being closely related to them.
This paper presents the nitrate trends during seasons, the samples was taken in December, April and June from 76 points, the influence of the season characteristics being obvious. Obtained data indicates an upward trend, so that nitrate concentrations increase from December to June, higher values registered on tributaries of Bahlui river, caused by of the land-use, smaller flow and seasons variation of other physic-chemical parameters, otherwise the synergistic action of the natural and anthropic sources and parameters.
Arc GIS software was used for illustrate the results followed by a statistics software were used to establish some correlations based on multivariate analysis. The analysis shows that non-point and anthropic sources of nitrates, influence nitrate regime during the succession of the seasons, nitrate levels almost doubled in surface water, or even higher in Bahlui river and its tributaries.
Assessment of a Large Subsurface Controlled Drainage and Irrigation System: III. Water chemistry of the tile effluent and its potential impact on surface water resources