Ground water nitrate pollution from agricultural sources in agriculture-dominated watersheds

Abstract

Diffuse pollution of water resources from agricultural sources is a major environmental issue both in the European Union and abroad. Water for drinking and agricultural use, high in nitrate is potentially harmful to human and animal health. Nitrate-(NO3) is the most common pollutant found in shallow aquifers due to both point and non-point sources and it is a naturally occurring form of nitrogen which is very mobile in water. It is essential for plant growth and is often added to soil to improve productivity. However, nutrients released in surface and ground-waters from cultivated fields and livestock production are the main source of concern, together with pesticides. The objectives of this paper are to document and evaluate regional trends and occurrences of nitrate in the ground water of agricultural watersheds in Central Greece. An agricultural land and water quality survey was performed and water samples from various wells were collected and analysed in laboratory. Also with the use of GIS (Geographic Information Systems) and Remote Sensing tools, the nitrates pollution of an agricultural ecosystem in agriculture-dominated watersheds and the correlated vegetation cover was studied. Results showed that nitrogen pollution from agricultural sources is characterised by remarkable temporal and spatial variability, depending on the interplay of the effects of human driving forces (land use, agricultural demands and activities) with environmental variables (climate, soil and topography). These phenomena differ in their scale and spatial features, which is a factor that should be accounted for when designing and implementing policy measures and management practices.