[In-situ Study on Effects of Combined Amendment on Translocation Control of Pb and Cd in Soil-Vegetable System]

An in-situ study aiming at remedying arid land complexly polluted with Pb and Cd by using combined amendment LS (a mixture of limestone and sepiolite with a ratio of 2 : 1) was conducted in a mining area in southern Hunan, China. The main objectives of this study were to discuss the effects of LS application at different amounts (0 , 2, 4, 8 g x kg(-1)) on the adsorption and accumulation of Pb and Cd in eggplant and amaranth, and to control the translocation and transportation of Pb and Cd among different parts of eggplant and amaranth. The results showed that: (1) Application of LS significantly increased soil pH values and decreased contents of exchangeable Pb and Cd in soil. (2) Application of LS led to an obvious reduction in contents of Pb and Cd in different parts of eggplant and amaranth. Compared with the control group, the contents of Pb and Cd in edible part of eggplant were decreased by 44.7% - 78.6% and 36.0%-78.7%, and those reductions for amaranth were 45.8%-59.1% and 40.0%-87.2%, respectively, when the LS applying ratios ranged 2-8 g x kg(-1). (3) Application of LS reduced the translocation factors of Pb and Cd among different parts of these two kinds of vegetables. The translocation ability of Cd among root, stem, and fruit (in eggplant) or leave (in amaranth) in these two vegetables was greater than that of Pb. However, application of LS with different amounts did not change the sequence of translocation factors of Pb and Cd among different parts of these two kinds of vegetables.