Research on the ecological risk of heavy metals in the soil around a Pb–Zn mine in the Huize County, China

Abstract

The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb-Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil were analyzed for the total metal concentration by acid digestion and sixty-eight selected soil samples were used to determine the chemical fractionation of heavy metals with the modified BCR sequential extraction method. The pollution index of the heavy metals indices for As, Cd, Cr, Cu, Hg, Pb and Zn of non-agricultural soil and agricultural soils in the study area indicated the spreading of heavy metal pollution. Sequential extraction showed that most of Cd existed in an exchangeable form (31.2 %). The available content of Pb, Cu and Zn was mainly distributed in acid extractable fractions and Fe/Mn oxide fractions (27.9, 30 and 27.2 %), and Hg, As and Cr were mainly associated with residual fractions (90.4, 72.9 and 76.8 %). The risks of heavy metals were also evaluated by the risk assessment code (RAC) and potential ecological risk index, respectively. The results of RAC showed a medium and high risk of Cd (45.6 and 54.4 %), medium risk of Zn (100 %), low and medium risk of Cu (41.2 and 58.8 %), largely no risk of Hg (97.1 %), and mainly low risk of As and Pb (92.6 and 91.8 %). The range of the potential ecological risk of soil was 58.2-1839.3, revealing a considerably high ecological risk in the study area, most likely related to acid mine drainage and the mining complexes located in the area. The results can be used during the ecological risk screening stage, in conjunction with the total concentrations and metal fractionation values, to better estimate ecological risk.

Accumulation Characteristics and Chemical Speciation of Cd, Zn and Pb in Soils Impacted by a Pb-Zn Mining Area

“…However, not much literature reports systematically the accumulation of heavy metals in soils. To be specific, S. J. Lu et al 6 discovered that the high ecological risk of the area was most likely related to acid mine drainage and mining complexes in the soil around the Pb-Zn mine in Huize County, China. J. Y. Qi et al 7 evaluated the health risks of heavy metals in soils collected from a Pb-Zn mining area with exploitation history of 60 years in southern China, and discovered that Cd and Zn were found mainly in the upper 60 cm of the soil, whereas Pb was mainly in the upper 40 cm, and concluded that there was a high health risk, especially for children.…”

Heavy metals distribution and risk assessment in soil from an informal E-waste recycling site in Lagos State, Nigeria

“…There are relatively few data on the potential bioavailability and mobility of heavy metals in E-waste recycling sites. Although the total concentration of heavy metals provides information about the quantity of pollutant present in soils, the information is inadequate to assess their potential toxicity or bioavailability as the toxicity of heavy metals is related to their chemical forms and species (Wali et al 2014;Lu et al 2015). Heavy metals may occur in different chemical forms as they interact chemically or physically with other compounds, and may also be partitioned into different fractions (Vega et al 2004;Shivakumar et al 2012).…”

Biodisponibilidad de elementos potencialmente tóxicos en suelos cercanos al margen del arroyo Morón, provincia de Buenos Aires

“…y de D está asociada fundamentalmente a las fracciones MO e INOR, se puede decir que el riesgo de movilidad y susceptibilidad de ser absorbidos por las plantas -es decir su biodisponiblidad-son bajos. En relación a esto, debe destacarse que, aunque la concentración total de metales pesados es un buen indicador de la contaminación del suelo, la toxicidad potencial está más relacionada con su biodisponibilidad y especiación (Lu et al, 2015;Meng et al, 2017). Sin embargo, los EPT de estas fracciones (MO e INOR) pueden solubilizarse y pasar a formas de mayor biodisponibilidad, lo que dependerá de los equilibrios químicos que ocurren en el suelo.…”