桂北典型锰矿区周边土壤重金属污染状况及主要植物富集特征

In order to assess the heavy metal pollution of soils and crops around a typical manganese mine tailingin north Guangxi, and to select suitable plant materials for the remediation of heavy metal pollution in this area,23 dominant plant species, their rhizosphere soil, and nine crop samples were collected. The concentrations of Cd,Mn, Cr, Pb and Zn of the samples were analyzed. The ecological risks of heavy metals in the soils and crops wereevaluated using the single factor and comprehensive pollution index. The bioconcentration and translocationfactors of the dominant plant species were calculated. Results showed that Cd and Mn were the dominantpollutants in the soils of the studied area. The values of single factor pollution index of Cd and Mn reached 18.53and 147.09 respectively. The concentrations of Cd, Cr and Pb in crops such as Arachis hypogaea and Brassicachinensis exceeded the threshold values in the National Food Safety Standards (GB 2762-2017), which had greathealth risks. Among the 23 dominant plant species, the transport coefficients of Celosia argentea, Bidens pilosa,Emilia sonchifolia and Eremochloa ciliaris for several heavy metals were greater than 1, indicating that they havethe characteristics of metal accumulating plants. The heavy metal concentrations in roots of Arisaema erubescens,Ricinus communis, and Senecio scandens were relatively higher, while their transport coefficients were relativelylower. This indicated that they are root hoarding plant. The metal concentrations in the shoots and roots ofCrotalaria albida, Rottboellia exaltata, and Sonchus arvensis were relatively lower, while they kept healthy in thecontaminated soil. This indicated that they are elusive plants. The soils in the studied area were seriously pollutedby Cd and Mn. Celosia argentea is a potential plant material for the remediation of the co-contaminated soil.