Effects of amendments on remediation of heavy metal contaminated soil and accumulation of Cd and Pb in potato

With the development of agriculture and industry, a large amount of heavy metals are loaded into the soil, posing a high ecological and public health risk. Many methods have been proposed to repair heavy metal contaminated soil, such as electroremediation, chemical washing, phytoremediation and in situ fixation. In the above methods, the application of passivators to in-situ immobilization of heavy metals is an environmentally friendly and cost-effective choice. The effects of different amendments on the improvement of heavy metal contaminated soil and the accumulation of Cd and Pb in potato plants were investigated by using attapulgite, diatomite and humic acid as materials.The results showed that soil pH, organic matter content and cation exchange capacity increased after the application of amendments. Under the treatment of attapulgite+humic acid, the soil pH, organic matter content and cation exchange capacity were increased by 0.57units, 10.0 mg/kg and 7.28cmol/kg, respectively, compared with the control. The content of soil hydrolyzable nitrogen increased, and the content of available phosphorus decreased. The application of amendments increased soil enzyme activity; effectively reduce the bioavailability of Cd and Pb in soil ; under the treatment of attapulgite+humic acid, the contents of Cd and Pb in potato plants decreased by 85.50%and 55.54%respectively, and the contents of Cd and Pb in potato tubers decreased to 0.08 mg/kg and 1.41 mg/kg respectively. The application of amendments affected the accumulation and transport of heavy metals Cd and Pb in potato plants to a certain extent and promoted the transformation of Cd and Pb from acid-soluble and reduced states to oxidized and residual states.