Natural groundwater quality in Baden-Wuerttemberg

In order to investigate natural groundwater quality in Baden-Wuerttemberg, 250 water samples from wells and springs of catchments with only little anthropogenic influence were chemically analysed. The study focused on the quantitative analysis of trace elements from natural sources. To assess the influence of atmospheric deposition on groundwater quality over a period of one year, monthly precipitation samples obtained from five meteorologic stations were also analysed. The groundwater hydrochemical data were obtained from 15 different hydrogeochemical units. The analytical data from the precipitation samples provide valuable information regarding the concentration of several elements in the atmospheric deposition in Baden-Wuerttemberg. For near-surface groundwater with only limited anthropogenic influence, concentration ranges for more than 50 hydrochemical parameters are now available. The results provide a reliable database of the natural variation of trace elements. Potential anthropogenic influences can thus be evaluated by comparing future data against this natural background. For illustration, the results from the trace elements cobalt and uranium are presented in more detail. (orig.)