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

Abstract

An exploratory study on soil contamination of Cd, Zn, Pb was carried out in the surroundings of a historical, abandoned Pb-Zn mining area in Hunan Province, China. The accumulation in soils and representative plants of Cd, Zn, Pb and their chemical speciation were investigated. The obtained results indicated that Cd, Zn and Pb presented a significant contamination compared with Environmental Quality Standards for Soils in China (GB 15618-1995). The geoaccumulation index suggested the degree of contamination: Pb > Cd > Zn. The modified BCR sequential extraction results showed that Cd, Zn, and Pb exist in soil in a relatively unstable form, and will exert a bad effect on the plants grown in the soil. Heavy metals in oranges collected in the sampling area were tested to identify the extent of pollution. The results confirmed that the sampled oranges were polluted with Pb, which exceeded the national food safety standard by 3.4 - 6.3 times. Heavy metals in branches and leaves showed different accumulation characteristics than the fruits.

Pollution Assessment of Heavy Metals in Soils and Plants around a Molybdenum Mine in Central China

“…The dominant Cd fraction changed as the land uses altered, which is different with the Cu speciation distribution. The similar results were also reported that Cd dominant fraction was different among various soils [31]. The percentage of available Cd also differed between bulk soils and rhizosphere soils.…”

Evaluation and Speciation of Heavy Metals Contamination of Selected Artisanal Mining Sites in Mangu Local Government Area of Plateau State, Nigeria

“…In this assessment, only the soil labile fraction is taken into account because this fraction is often called the bioavailable fraction [11], [15]. According to Huang et al [17], "the concentration of heavy metal's solution in the soil, their form of association with other soluble species and the ability of the soil to release them from the solid-phase to the soil solution determine the mobility, bioavailability and the potential toxicity of these metals in the soil." They further stated that the knowledge of the chemical forms in which those metals are found reveals their behaviour within the environment.…”

Chemical Speciation and Potential Mobility of Heavy Metals in the Soils of Onitsha South Local Government Area Anambra Nigeria

“…Heavy metals commonly originate from two primary sources: natural background (lithogenic) sources and anthropogenic inputs, including metalliferous mining and industries, agrochemicals and mineral fertilizers, vehicle exhaust, sewage sludge and industrial wastes [3]. According to Huang et al [4], the concentration of heavy metal's solution in the soil, their form of association with other soluble species and the ability of the soil to release them from the solid-phase to the soil solution determine the mobility, bioavailability and the potential toxicity of these metals in the soil. The knowledge of the chemical forms in which those metals are associated reveals the metals behaviour, their mobility and bioavailability within the environment [5 and 6].…”