Vanadium in groundwater of the Eifel volcanic area, Germany

摘要

Elevated vanadium concentrations of up to 28 mu g/l were found in spring waters of the western Eifel volcanic area, Germany. The spatial distribution of the water samples indicates higher V concentrations in Cenozoic vulcanite than in neighboring Paleozoic areas. X-ray fluorescence analyses of the volcanic rock samples revealed a V enrichment up to four-fold above average earth crust values. Water elution tests showed enhanced mobility of the V inventory. Microprobe element mapping with thin slices of the volcanic rocks showed no correlation between Fe and V but revealed a spatial correlation between P and V. Microprobe chemical analysis of V-rich hot spots revealed V-bearing fluorapatite with up to 5% of the phosphate substituted by vanadate. Fluorapatite micro-grains are abundant in the rocks and may well represent a geogenic source for the V contamination of the groundwater. Hydrogeochemical modeling using PhreePlot shows the vanadate (V) species which dominate the V-enriched water samples.