EXTRACTABILITY OF ADDED LEAD IN SOILS AND ITS CONCENTRATION IN PLANTS

Abstract

The concentrations of Pb in five species of plants were found to increase with proximity of the sampling sites to a well-travelled highway.The Pb content of oats and alfalfa grown in four soils pretreated with PbCl₂ in pot tests varied inversely with the organic matter content and pH of the soils. The amounts of Pb taken up by the plants were reduced upon addition of phosphate or of lime to the acid soils. Furthermore, the beneficial effects of organic matter, phosphate and lime in reducing Pb in the plants were usually in accord with corresponding reductions in extractable Pb in the soils as measured in 1 N neutral ammonium acetate and 0.1 M CaCl₂.