Vegetative Growth and Trace Metal Accumulation on Metalliferous Wastes

Abstract

A greenhouse study was conducted to investigate the growth of the grass cover crops Agrostis capillaris, Festuca ovina, F. rubra, Lolium perenne , and Phleum pratense and their accumulation of Cu, Pb, Zn, Ni, and Cr in three metal‐contaminated wastes arising from a steelworks, a lead mine, and a chemical works. Soil metals were extracted by five reagents (Mehlich 1, 0.1 M HCl, 0.005 M DTPA, 0.005 M EDTA, 0.005 M NTA) and values were correlated with plant tissue accumulation of metals. Agrostis capillaris accumulated the greatest concentration of metals from each waste material. Dry matter production for all grasses decreased on contaminated substrates compared to the control; however, overall ground cover was satisfactory except for A. capillaris on the chemical works waste. Lolium perenne and P. pratense consistently produced the highest dry matter yields. All grasses accumulated excessive amounts of Cr on the chemical waste and Pb on the mine waste, presumably from reservoirs in the readily extractable and soluble forms. The extractability of most metals was generally 0.1 M HCl > Mehlich 1 > DTPA = EDTA = NTA. Mehlich 1 did not appreciably extract Pb from two wastes. No extractant was able to represent metal uptake by a particular grass in a linear fashion.