VEGETATIVE GROWTH AND TRACE-METAL ACCUMULATION ON METALLIFEROUS WASTES

A greenhouse study was conducted to investigate the growth of the gras s cover crops Agrostis capillaris, Festuca ovina, F. rubra, Lolium per enne, and Phleum pratense and their accumulation of Cu, Ph, Zn, Ni, an d Cr in three metal-contaminated wastes arising from a steelworks, a l ead mine, and a chemical works, Soil metals were extracted by five rea gents (Mehlich 1, 0.1 M HCl, 0.005 M DTPA, 0.005 nl EDTA, 0.005 M NTA) and values were correlated with plant tissue accumulation of metals, Agrostis capillaris accumulated the greatest concentration of metals f rom each waste material. Dry matter production for all grasses decreas ed on contaminated substrates compared to the control; however, overal l ground cover was satisfactory except for A. capillaris on the chemic al works waste. Lolium perenne and F. pratense consistently produced t he highest dry matter yields. All grasses accumulated excessive amount s of Cr on the chemical waste and Pb on the mine waste, presumably fro m reservoirs in the readily extractable and soluble forms. The extract ability of most metals was generally 0.1 nl HCl > Mehlich 1 > DTPA = E DTA = NTA. Mehlich 1 did not appreciably extract Ph from two wastes. N o extractant was able to represent metal uptake by a particular grass in a linear fashion.