Cadmium In Groundwater Of Northwestern Germany-Origin, Mobilization And Assessment According To The European Water Framework Directive

Nine groundwater bodies in northwestern Germany had a "bad" status according to the Water Framework Directive due to cadmium concentrations above 0.5 mu g/l. Data from fertilizer, soil, and groundwater analyses from statewide monitoring were used to study geogenic input, fertilizer emissions, and atmospheric deposition. Until 2016, cadmium input decreased to 0.74 g/(ha center dot a) from phosphate fertilizers and 0.2 g/(ha center dot a) from atmospheric deposition. Groundwater data revealed a significant correlation between cadmium and nitrate plus acidification mainly in the agriculture-intensive Geesten areas. High groundwater recharge rates promote a direct impact on groundwater in agricultural and forestry areas causing increased cadmium solubility. Time series analysis identified increasing cadmium trends and showed that Geesten areas with elevated cadmium concentrations in groundwater corresponded to areas where nitrate reduction measures are needed. Cadmium background levels in groundwater ranged from 0.01 mu g/l to 0.98 mu g/l. Using the better differentiated background levels allowed a re-evaluation of the chemical status of groundwater bodies.