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| Effects of straw amendment on methylmercury accumulation in soil and crop plants under wheat-rice rotation |
| Received:April 12, 2016 |
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| KeyWord:straw return;paddy soil;wheat-rice rotation;crop;methylmercury |
| Author Name | Affiliation | E-mail | | CHEN Zong-ya | College of Resources and Environmental Engineering, Guizhou University, Guiyang 550002, China | | | WANG Yong-jie | School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China | | | SHU Rui | School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing 210023, China | | | FU Fang-jing | Guizhou Rural Economic Information Center, Guiyang 550002, China
Institute for Information on Agricultural Quality and Food Safety, Guiyang 550002, China | | | WU Yong-gui | College of Resources and Environmental Engineering, Guizhou University, Guiyang 550002, China | ygwu72@126.com |
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| Abstract: |
| There is growing concern about methylmercury(MeHg) accumulation in crop plants in Hg-contaminated areas. To investigate the possible influences of straw amendment on soil methylmercury levels and its accumulation in crop plants, mercury-contaminated paddy soil was collected from Wanshan mercury mine area and amended with 1%(W/W) crop straw(wheat or rice) in a wheat-rice rotation system. At different stages(e.g., seedling, tillering, jointing, flowering and harvesting) of plant growth, the soil and plant samples were collected and analyzed for MeHg. The results show that straw amendment could lead to a substantial increases in MeHg levels in both soils and plants. Soil MeHg increased by 127.1% under wheat-straw amendment and 25.1% under rice-straw amendment, respectively. This was possibly due to the different planting conditions. Correspondingly, MeHg levels in root, aboveground part and grain of wheat increased by 124.6%, 79.2% and 169%, respectively, compared to the control. Similarly, MeHg levels in root, aboveground part and grain of rice increased by 40.1%, 61.7% and 25.9%, respectively. Overall, there is a positive relationship between the crop plant MeHg levels and soil MeHg levels under wheat-rice rotation, indicating that straw amendment could increase soil MeHg levels and subsequently the MeHg accumulation in crops, which could enhance the potential risk of human exposure to MeHg in mercury-contaminated areas. These results suggest that it should be cautious when promoting straw amendment in mercury-contaminated areas. |
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