Heavy Metal Loads to Agricultural Soils in Germany from the Application of Commercial Phosphorus Fertilizers and Their Contribution to Background Concentration in Soils

Abstract

Statistical data on the annual sale of phosphorus (P) containing mineral fertilizers in Germany combined with data on toxic elements in mineral fertilizers allow an estimation of heavy metal loads to agricultural land. For the time period from 1950/51 to 2009/2010, the mean annual loads of the elements As, Cd, Cu, Ni, Pb, U and Zn to agricultural land in Germany exclusively from the application of P fertilizers amounted to: As 40, Cd 22, Cu 95, Ni 54, Pb 11, Zn 431 and U 114 t/yr, while maximum values reached: As 73, Cd 42, Cu 146, Ni 90, Pb 20, Zn 764 and U 228 t/yr. Depending on the soil group looked at, the contribution over the last sixty years of mineral fertilizer bound heavy metal inputs to average background concentrations of agricultural in Germany ranges between 0.4–1.4% for As, 3.5–12.3% for Cd, 0.2–1.1% for Cu, 0.03–1.5% for Ni, 0.03–0.1% for Pb, 0.3–1.8% for Zn and 4.4–13.7% for U. It can be concluded that there is an important urgent need to limit the concentration of these elements in mineral fertilizers given that these heavy metals are toxic, causing harm to the environment and public health and for example the preferable pathway for Cd into the food chain is the soil-plant system, and for U intake by drinking water.