Study on Remediation of Cd Contamination in Riverbed Soils Around Outfalls by Six Typical Plants

Abstract

To study the phytoremediation effect of Cd pollution in the riverbed soil around the sewage, the effects of six typical plants, namely Solanum nigrum L (SNL), Phytolacca acinosa roxb (PAR), Nephrolepis auriculata (L.) (NAL), Pogonatherum crinitum (Thunb.) kunth (PCK), Pteris vittata L (PVL), and Sedum lineare Thunb (SLT), on the Cd concentration in the soil with different pollution levels (3, 5, and 8 mg/kg) and the Cd concentration in different parts of the plant (root, stem, and leaf) after planting were studied to explore the remediation effects of different plants on different Cd polluted soils. The research results show that when the concentration of Cd in the soil was 3 mg/kg, the Cd enrichment coefficient of SNL and SLT was the largest. At the same time, the Cd concentrations in the stem and leaf of SNL and the root and stem of SLT are 26.18, 40.26, 34.38, and 49.45 mg/kg, which can be recycled by composting. Therefore, it is recommended to plant SNL or SLT to repair the Cd pollution in the urban residential area. At 5 mg/kg, the Cd enrichment coefficient of SLT was the largest. At the same time, the concentration of Cd in roots and stems was 65.79 and 108.11 mg/kg, which could be reused by composting and hydrothermal transformation. Therefore, it is recommended to plant SLT to repair the Cd pollution in the light industry zone. At 8 mg/kg, the Cd enrichment coefficients of NAL and SNL were the largest. At the same time, the stem and leaf of SNL and the leaf of NAL could be reused by composting and hydrothermal transformation. Therefore, it is recommended to plant NAL to repair the Cd pollution in the heavy industry zone and mix NAL and SNL to repair the Cd pollution in the chemical industry concentration zone.