The accumulation of trace metals in vegetables grown on contaminated soils. A literature survey

In the frame of a revision of the Dutch Guideline for Soil Protection a review of the literature concerning trace element contents of vegetables grown on polluted soil is presented. The elements considered were arsenic, barium, cadmium, cobalt, copper, mercury, lead, molybdenum, nickel, tin, and zinc. The content of each of these elements in a vegetable may vary widely. Furthermore, different vegetable species may differ in trace element uptake. Even if we consider the accumulation of only one element in one kind of vegetable, it is difficult to predict plant contents from soil contents, because of the great number of factors that influence accumulation. These factors may be distinguished into soil and plant bound factors. The factors that appear to be important from the literature are summarized. Furthermore, all available data with respect to trace elements contents of vegetables grown on polluted soils (preferably under field conditions), are brought together in this report. Finally, biological concentration factors (BCFs) for the transfer of trace elements from soil to vegetables were proposed. Here a distinction was made between BCFs for potatoes, that make up a large part of our diet, and other vegetables. The content of a number of elements in vegetables appeared to be limited due to phytotoxicity.DGM/B