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Geoscience ›› 2021, Vol. 35 ›› Issue (05): 1433-1440.DOI: 10.19657/j.geoscience.1000-8527.2021.25

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Distribution Characteristics and Pollution Evaluation of Heavy Metals in Typical Organic Rice in Lingchuan County, Guilin City

ZHU Chao1(), WEN Meilan1(), LIU Panfeng1,2, CHEN Binyan3, BAO Houyin1, ZHAO Yinqiang1, CHEN Hao1, YANG Yibo1   

  1. 1. College of Earth Sciences,Guilin University of Technology,Guilin,Guangxi 541006,China
    2. College of Environmental Science and Engineering,Guilin University of Technology,Guilin,Guangxi 541006,China
    3. Guilin Plant Protection Station,Guilin,Guangxi 541001,China
  • Received:2020-05-12 Revised:2020-07-05 Online:2021-10-10 Published:2021-11-04
  • Contact: WEN Meilan

Abstract:

In order to understand the content, distribution characteristics and health risks of heavy metals in the soil and rice in the typical rice area of Lingchuan County, Guilin City, we selected typical rice fields and collected 10 sets of samples of rice roots, stems, leaves, rice and corresponding root soils. The contents of 8 heavy metals including As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the soil were determined respectively. The bio-concentration factors (BCF) and transfer factor (TF) of each element were calculated. The enrichment and migration law of heavy metals in different parts of rice were summarized. According to the Risk Control Standard for Soil Contamination of Agricultural Land (GB 15618—2018), the Green Food Environmental Quality for Production Areas (NY/T 391—2013) and Food Hygiene Standards (GB 2762—2017),heavy metal pollution in soils and food health risks were determined. The results show that: (1) The brown rice produced in the research area has no food safety risk, and the heavy metal content in the soil does not exceed the risk control value, but 3 of the 10 sample fields have a Cd content higher than the agricultural land soil pollution risk screening value, and all the sample fields are unable to meet the quality requirements of the green food origin. (2) Comparing the bio-concentration factors of different parts of rice, it is found that the bio-concentration factors of most elements are the largest at the roots and the smallest at the brown rice. The average of bio-concentration factors are 1.13 for roots, 0.26 for stems, 0.20 for leaves and 0.10 for brown rice. (3) Comparing the bio-concentration factors and transfer factor between different elements, it was found that As is relatively easy to accumulate from the soil to the roots, Pb is weak in activity and not easily absorbed by rice, Cu and Zn are relatively easy to transport in rice. In summary, we recommend that local authorities pay attention to the risk of excessive Cd, strengthen land quality monitoring, and take measures such as increasing the application of organic fertilizers and planting rice with low accumulation varieties when necessary to reduce the risk of heavy metals exceeding the standard.

Key words: heavy metal, soil-rice system, migration pattern, pollution assessment, Lingchuan County

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