Pollution, fractionation, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils from a Pb/Zn mining area

Abstract

This study was conducted to investigate the pollution load index, fraction distributions, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils collected from a Pb/Zn mine in Chenzhou City, China. The samples were analyzed using Leleyter and Probst's sequential extraction procedures. Total metal concentrations including Pb, Cd, Cu, and Zn exceeded the maximum permissible limits for soils set by the Ministry of Environmental Protection of China, and the order of the pollution index was Cd > Zn > Pb > Cu, indicating that the soils from both sites seriously suffered from heavy metal pollution, especially Cd. The sums of metal frac- tions were in agreement with the total contents of heavy metals. However, there were significant differences in fraction distributions of heavy metals in garden and paddy soils. The residual fractions of heavy metals were the predominant form with 43.0% for Pb, 32.3% for Cd, 33.5% for Cu, and 44.2% for Zn in garden soil, while 51.6% for Pb, 40.4% for Cd, 40.3% for Cu, and 40.9% for Zn in paddy soil. Furthermore, the proportions of water-soluble and exchangeable fractions extracted by the selected analytical methods were the lowest among all fractions. On the basis of the speciation of heavy metals, the mobility factor values of heavy metals have the following order: Cd (25.2-19.8%) > Cu (22.6-6.3%) > Zn (9.6-6.0%) > Pb (6.7-2.5%) in both contaminated soils.

Concentrations, spatial distribution, and risk assessment of soil heavy metals in a Zn-Pb mine district in southern China

“…In summary, the mobility of metals in soil profiles could be classed as Cd > Zn ≫ Pb > As. Similar phenomena were also observed by other researchers when they studied the mobility of heavy metals in a Pb-Zn smelting area (Li et al 2015;Bi et al 2006;Lei et al 2010). …”

Assessment of Heavy Metals Contamination and Enzymatic Activity in Pine Forest Soils under Different Levels of Anthropogenic Stress

“…The pollution level by a given heavy metal (i) was evaluated with the single pollution index (Pi) calculated as the ratio between the metal concentration (Ci) in a soil sample and permitted standard of the same metal (Si): [21,22] Permitted standard for this study was recommended by the regulation of the minister of the environment about the standards of soil and ground quality (300 mg kg -1 Zn, 100 mg kg -1 Pb, and 4 mg kg -1 Cd) [23]. The overall pollution status of the surface soils by the heavy metals was assessed using the Nemerow pollution index (Pn) [22,24]:…”

Apportionment of Hazardous Elements in Agricultural Soils Around the Vicinity of Brick Kiln in Bangladesh

“…Hazardous elements are of great concern due to their wide sources, toxicity, non-biodegradable properties and accumulative behaviors [2]. Trace metals such as Chromium (Cr), Nickel (Ni), Arsenic (As), Cadmium (Cd) and Lead (Pb) have been considered as the most toxic elements in the environment by the US Environment Protection Agency (EPA) [1,3]. Brick production in brick kiln is traditional and fast growing industry in many parts of Asia like Bangladesh.…”