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Spatial distribution of smelter emission heavy metals on farmland soil
Citation:
Xing, W., Y. Zheng, K. Scheckel, Y. Luo, AND L. Li. Spatial distribution of smelter emission heavy metals on farmland soil. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 191(2):115, (2019). https://doi.org/10.1007/s10661-019-7254-1
Impact/Purpose:
Heavy metal accumulation in soil has attracted increased attention recently from residents to regulators in China. According to the bulletin of Ministry of Environmental Protection and Ministry of Land Resources (2014), 16.1% of the land in China is polluted, with Cd, Hg, As, Cu and Pb ranked as priorities in the pollutant list. In China, heavy metal pollution in soil poses a more serious risk to the health of local inhabitants than in most other countries, due to the low farmland area per capita in the polluted areas and the short distance between smelters and resident communities, which is true for many smelters in China. For source identification of heavy metals in soil, Pb isotopic analysis has been successfully utilized. Recently, Bi et al (2006) applied elemental correlation of the ratios between Cd and Pb in contaminated soils to discriminate the pollution from atmospheric deposition and that from solid waste of Zn smelting. They concluded that because of the lower boiling point of Cd than those of Pb and Zn, Cd will accumulate in particulate matters while Pb and Zn tend to accumulate in solid waste during the smelting process. Shen et al (2017) demonstrated that pollution of soil samples from different sampling sites with similar Cd/Pb ratios was distinguishable to identify the source. Non-linear correlation between Cd, Pb concentrations of soil samples to the distance of the smelters have been noticed in different works, due to the deposition characteristics of the particulate matters from the stack. Thus, if a soil is affected by pollution sources from more than one lead smelting stack, the correlation may very likely to change. As a result, it is possible to discriminate pollution sources of heavy metals in soils within an area predominantly affected by atmospheric deposition from a smelter. The purpose of the work was to, i) investigate the distribution of heavy metals in soils in the vicinity of lead smelters by sampling a larger area than the previously reported studies in Jiyuan, and ii) use the distribution of heavy metals in soils to estimate the contribution of different sources on the accumulation of heavy metals in soils near a lead smelter.
Description:
This work was conducted to explore heavy metal pollution in soils in an area near lead smelters in Jiyuan City, which is one of the main lead production areas in China. Altogether, 88 topsoil samples (0–20 cm) were collected from farmlands near the Yuguang lead smelting facilities; the sampling sites were 1570 to 6388 m to the main stack of the Yuguang. Analysis of the samples indicated that (i) the ranges of total Cd and Pb concentrations were 0.81–4.30 and 64.5–435 mg kg−1, respectively, mean pollution indices (concentration in soil/background value, PI) were 32.8 and 9.11, respectively, and the concentrations of total Cu, Zn, and Ni were slightly higher than the background values. Mean concentrations of DTPA-extractable Cd and Pb were 0.752 and 58.7 mg kg−1, respectively. (ii) The total concentrations of Cd, Pb and Pb/Cd ratios of samples decreased as the distance to the main stack of the Yuguang increased. Abnormal variations of these trends suggested these parameters of certain samples were affected by pollution sources other than the Yuguang. (iii) Judged by the results of this work, the area of the heavy metal-polluted land in Jiyuan was much greater than 115 km2, a value reported by an earlier investigation. These results indicate that the soil in the study area was polluted by Cd and Pb emissions from more than one polluting sources, the variation of Cd, Pb concentration and Pb/Cd ratios of samples to the distance of the pollution source can be potentially used for pollution source identification.
URLs/Downloads:
DOI: Spatial distribution of smelter emission heavy metals on farmland soil
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