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| Contents and Health Risk Assessment of Heavy Metals in Wheat and Rice Grown in Tianjin Sewage Irrigation Area, China |
| Received:November 17, 2014 |
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| KeyWord:heavy metal pollution;daily intake;target hazard quotient;health risks;Tianjin sewage irrigated area |
| Author Name | Affiliation | E-mail | | SUN Ya-fang | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | | | WANG Zu-wei | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | wangzuwei@126.com | | MENG Wei-qing | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | | | HU Bei-bei | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | | | HOU Ying-ying | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | | | WANG Zi-lu | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | | | ZHANG Hui | College of Urban & Environment Science, Tianjin Normal University, Tianjin 300387, China | |
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| Abstract: |
| Sewage irrigation has caused soil heavy metal pollution. In this study, we collected 24 wheat samples and 29 rice samples and corresponding soil samples from sewage-irrigated area and 10 wheat samples and 14 rice samples and corresponding soil samples from clean water irrigation area in Tianjin sewage irrigation area. Concentrations of heavy metals such as Cd, Cu, Pb, Zn and Cr in both crops and soils were determined by inductively coupled plasma atomic emission spectrometry. Concentrations of As and Hg were measured by atomic florescence spectrometry. Results showed that continuous applications of wastewater had led to accumulation of heavy metals in soils. The concentrations of Cd, Zn and Hg in soils were 0.46 mg·kg-1, 129.05 mg·kg-1, 0.52 mg·kg-1,respectively, which exceeded the allowable limits of the second grade standards of soil environmental quality of Tianjin. The concentrations of Pb in wheat and rice were respectively 0.14 mg·kg-1, and 0.62 mg·kg-1, being higher than the safe limits for human consumption and thus having human health risk. Transfer factors of Zn and Cd were higher than those of other elements. Concentrations of heavy metals such as Cd, Zn, and As in some wheat samples and Hg and As in some rice samples exceeded the safe limits of China National Food Standard, suggesting their potential ecological risks to human health. Target hazard quotient(THQ) of individual metal was below 1, implying that heavy metals through consumption of either wheat or rice had little health risks. However, the sum of THQs of As for wheat and rice was above 1, indicating As health risk to the local residents via consumption of wheat and rice. |
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