NITRATE AND CHLORIDE LOADINGS AS ANTHROPOGENIC INDICATORS

Agricultural, urban, forest and groundwater protection areas as well a s nitrate and chloride concentrations are documented in maps. Areal di stribution shows regionally elevated nitrate and chloride concentratio ns in connection with urban areas and agricultural use. Transport of n itrate and chloride tends to be conservative in the groundwater of the investigated area. Therefore, the elevated concentrations of these an ions are suitable as indicators of anthropogenic impact on the groundw ater. The average concentration of nitrate and chloride from all surve yed wells amounts to 26 and 17 mg L-1, respectively. It is shown that wells recharged through forests have lower nitrate and chloride concen trations (average: 21 and 13 mg L-1, respectively). Wells affected by waste deposits have an average nitrate concentration of 35 mg L-1 and chloride concentration of 24 mg L-1. Urban use results in an average v alue of 28 mg L-1 nitrate and 24 mg L-1 chloride. As nitrate and chlor ide concentrations are stable with respect to the depth of the groundw ater table, degradation processes or other protective effects of the u nsaturated zone can be omitted.