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| Selenium, arsenic, mercury and cadmium in tea leaves and infusion of a green tea grown in an area with a high geological background of selenium and cadmium |
| Received:March 09, 2019 |
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| KeyWord:Se-rich soil;heavy metal;leaching;health risk;tea leaves |
| Author Name | Affiliation | | YANG Ru-yi | School of Environmental Science and Engineering, Anhui Normal University, Wuhu 241002, China
Anhui Provincial Engineering Laboratory of Water and Soil Pollution Control and Remediation, Wuhu 241002, China | | YANG Cheng | School of Environmental Science and Engineering, Anhui Normal University, Wuhu 241002, China | | SHI Xiao-jing | School of Environmental Science and Engineering, Anhui Normal University, Wuhu 241002, China | | ZHANG Meng-ting | School of Environmental Science and Engineering, Anhui Normal University, Wuhu 241002, China | | GAO Ye-neng | School of Environmental Science and Engineering, Anhui Normal University, Wuhu 241002, China |
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| Abstract: |
| It is very important to highlight the biogeochemical cycle of trace elements and their accumulation in crops and potential health risks in high geological background areas. The accumulation of selenium (Se), arsenic (As), mercury (Hg)and cadmium (Cd)in tea leaves was investigated and the impacts of harvest season, leaf maturity and drying temperature on the concentrations of these trace elements were analyzed. The optimal tea making conditions were obtained based on the maximum leaching of Se in the infusion, and the leaching characteristics of 4 trace elements and associated health risks were evaluated. The results showed that soil Se ranged from high to excessive (46.67%)according to the landscape ecological background value of Se in China. The concentration of Cd in the soil was much higher than the risk screening value and the proportion of acid exchangeable Cd species was 57.31%. Tea samples were recognized as Se-rich tea and contained normal amounts of As, Hg and Cd, according to the national standards of China. Soil Se did not have any antagonistic effect on the accumulation of toxic metals. On the contrary, it was positively correlated with Hg concentration in the tea leaves. A high-temperature for drying resulted in a 63.51% loss of foliar Se, while harvest season and leaf maturity exhibited significant effects on the concentrations of As, Hg and Cd. The leaching of Se was mainly controlled by temperature and brewing times and only 26.06% of Se was leached into the infusion under the optimal conditions. In contrast, As and Hg in the infusion were mainly subjected to brewing times, duration and temperature. There was no obvious health risk in the consumption of Se-rich tea in this study because all the target hazard quotients (THQ)were less than 1. The results indicated that the accumulation of trace elements in tea leaves and the associated health risks in a high geological background area were different from those in polluted areas. |
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