Distribution of Cd, Cu, Pb and Zn in soil, wheat grain and scalp hairs of local residents in the vicinity of a lead smelter in Jiyuan, China

Yuqing Zhang1, L. Li1, W. Xing1, K. G. Scheckel2

1 School of Chemistry and the Environment, Henan University of Technology, China

2 U. S. Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH 45268, USA

740903003@qq.com

In order to elucidate the distribution of heavy metals in soil, crop and human body in Pb smelting impacted areas, paired soil and wheat grain samples (n=40), and samples of scalp hairs of local residents (n=42) were collected from villages of Qingduo(QD), Guofu(GF) and Beishe(BS), in Jiyuan, China. The distances between these three villages and a local large lead smelter were 1, 3 and 6 km, respectively. The samples were analyzed for the concentrations of Cd, Cu, Pb and Zn. For all the four metals, the concentrations of soil ranked QD > GF > BS. }For samples from QD, GF and BS, the mean concentrations of Cd were 4.34, 2.11 and 0.839 mg kg-1, respectively. The concentrations of heavy metal of the soil and wheat grain collected from QD were significantly higher than those from GF and BS (p<0.05). Significant linear correlation was found between whole wheat grain flour and soil for} Cd, Pb and Cu concentrations (p< 0.01), however, the concentration of Pb in wheat bran was not significantly correlated with soil Pb concentration (p=0.705), indicating the importance of absorption of Pb via the aerial part of wheat on the accumulation of Pb in wheat bran. Significant positive linear correlation was found between Pb and Cd in the whole wheat grain flour for all the wheat samples (p<0.05). Compared with the National Food Quality Standard (GB 2762-2017), 100% and 95% of all the grains samples had Cd and Pb concentrations higher than the respective maximum permissible concentrations (MPCs), respectively, indicating the high risk of Cd and Pb to local residents through food chain. The mean concentrations of Cd, Cu, Pb and Zn in wheat bran were 7.54, 2.66, 7.17 and 2.60 times of those of the whole wheat grain flour, respectively, indicating the more concentrated distribution of Cd and Pb in wheat bran than Cu and Zn. The mean concentration of Cd of scalp hair samples from QD, GF and BS were 3.31, 0.778 and 0.382 mg kg-1, respectively; those of Pb were 132, 18.9 and 20.2 mg kg-1, respectively; those of Cu were 10.4, 8.79 and 8.75 mg kg-1, respectively; those of Zn were 147, 128 and 134 mg kg-1, respectively. However, only the concentrations of Cd and Cu in scalp hair from QD were significantly higher than those from GF and BS (p< 0.05). Higher concentrations of all these four metals were found in hairs of male than those of females, with the differences of Cd and Pb significant at 0.05 levels, indicating higher risk of Cd and Pb accumulation in male residents, this may very likely be the results of more frequent exposure of male residents to heavy metal-containing particles in their career. Negative correlation was found between Zn concentration in hair and the age of residents (p< 0. 01), confirming the loss of Zn in human body as ageing. The results of this work indicate the obvious concentrated distribution of heavy metals in the wheat bran, and the substantial contribution of atmospheric deposition on the accumulation of Pb in wheat grains; the Cd and Cu accumulation in human body of local residents are enhanced by the pollution from the smelter. However, because the smelting does not resulted in obvious accumulation of Cu in soil and wheat grains, the accumulation of Cu in the scalp hair may be a side effect of the interaction between different metals in human body.

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