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| Human health risk assessment owing to Pb and Zn of farmland soils in Shifang City, southwest China |
| Received:January 18, 2018 |
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| KeyWord:farmland soil;heavy metal;bioaccessibility;USEPA model;health risk assessment |
| Author Name | Affiliation | E-mail | | CHEN Dan | Department of Environmental Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610207, China | | | ZHOU Yu-jie | Department of Environmental Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610207, China | | | ZHANG Jia-wen | Department of Environmental Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610207, China | | | LUO Xue-ru | Department of Environmental Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610207, China | | | YANG Jin-yan | Department of Environmental Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610207, China | yanyang@scu.edu.cn |
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| Abstract: |
| The possible health risk owing to soil contamination with Pb and Zn for the local populations by the oral intake of the contaminants in Shifang City, Sichuan Province, southwest China was investigated. Farmlands around phosphate fertilizer plants in Chuanxindian and Hongda, and around the industrial park in Shuangsheng were selected as sampling areas. A farmland in Majing was selected as the control area. Total concentrations of Pb and Zn, and the distribution of Zn were determined. The fractions and bioaccessibility of Pb and Zn were studied by the modified method proposed by the Community Bureau of Reference (BCR) and the simple bioavailability extraction test (SBET), respectively. Additionally, the health risk models recommended by United States Environmental Protection Agency (USEPA) were used to assess the health risk owing to Pb and Zn exposure. According to the screening values of Risk Control Standard for Soil Contamination of Agricultural Land in Soil Environment Quality (GB15618-2018), Pb did not cause pollution in the study area, whereas Zn caused slight pollution. The total concentrations of Pb and Zn in the industrial areas were higher than those in the non-industrial area. The highest concentration of Zn was observed at a distance of 300~400 m from the chimney in the direction of the flow of effluents from the chimney outlet. In Majing, Chuanxindian, Hongda, and Shuangsheng, the bioaccessibility of Pb was 8.9%, 28.8%, 18.0%, and 77.3%, respectively, and the corresponding values for Zn were 5.1%, 7.1%, 6.7%, and 24.5%, respectively. The bioaccessibility of Pb and Zn in the industrial areas was higher than that in the non-industrial area. Pb and Zn existed mainly in the residual fraction in the sampling areas. There was a significant positive correlation (R2=0.999 3) between the bioaccessible and the acid-extractable fractions of Zn. However, no such correlation was noted for Pb. Based on both the total concentrations and the bioaccessibility, the health risks of Pb and Zn for both adults and children were within the tolerable limit, but the potential health risk for children could not be overlooked. Moreover, based on the total concentrations and the bioaccessibility, the contributions of Pb for the total non-carcinogenic risk (HI) were 96.5% and 98.6%, respectively. Through the modified models by the bioaccessibility replacing the total concentrations of Pb and Zn, the potential health risks were significantly reduced. |
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