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

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.