DETERMINATION OF NITRATE AND NITRITE ORIGINS IN THE SOILS AND GROUND WATERS OF THE AREA BETWEEN MERSIN-TARSUS (TURKEY) USING GEOGRAPHIC INFORMATION SYSTEMS

The study area is located east of the city of Mersin where both agricultural (especially greenhouse cultivation) and industrial activities are very intense. The aims of this study were to determine nitrate and nitrite levels in soil and ground water samples collected from the area and their spatial distributions using a Geographic Information System (GIS) and to find out their potential sources of pollution. For this purpose, 208 topsoil samples (from a depth interval of 0-15 cm) and 157 ground water samples were collected in August 2007 from the area between Mersin-Tarsus (Turkey). According to the results obtained from this study; nitrate concentrations in soil samples range between 10-1478 mg/L; whereas nitrite concentrations range between 0.0-9.6 mg/L. In ground water samples; however, nitrate concentrations range between 0-1834 mg/L; whereas nitrite concentrations range between 0.0-10.3 mg/L. Comparison of the spatial distributions of nitrate and nitrite in soils and ground water of the area using GIS revealed that their spatial distributions do not show a strong correlation. Examination of the thematic maps produced by GIS indicate that high nitrate and nitrite concentrations in ground water generally occur around settlement areas and industrial facilities; whereas, high nitrate and nitrite concentrations in soils of the area generally occur in places where agricultural activities are very intense.