Impact of New Soil Amendments on the Uptake of Lead by Crops

Abstract

In the present article, the reclamation of lead (Pb)-contaminated soils by adding zeolite, bentonite, goethite, and two newly produced adsorbents consisting of zeolite and goethite (systems I and II) was studied. These adsorptive materials were used to reduce the transfer of Pb to plants that were cultivated to these soils. For this purpose, a greenhouse pot experiment was conducted in four replicates as follows: 5 g of zeolite or bentonite or 1 g of goethite or zeolite-goethite (system I or II respectively) were added in pots that contained 1 kg of soil. Then, 1 mL of lead nitrate (0.04 M) solution and plant seeds of wheat, maize, and cotton were added. A total of 300 pots were produced including also the unamended control. Forty days after germination, the plants were collected, the morphological characteristics were identified and the available Pb in soil [extracted with diethylenetriaminepentaacetic acid (DTPA)] and the total Pb in plants were determined. The experimental results show that the greatest decrease of available Pb was present in soils that contained goethite and zeolite-goethite (system II) in pots grown with wheat and maize, respectively. Moreover, the uptake of Pb by plants was significantly reduced in all treated soils, especially in the zeolite- goethite treatment (system I) in pots grown with maize, compared to the unamended control.