Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area
Methylmercury (MeHg) contaminated rice is a global issue, particularly in mercury-polluted areas, posing a potential threat to human health. The sources and transformations of mercury (Hg) species in rice are critical points that are not yet fully understood. In this study, field experimental pots t...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co. Ltd.
2021-05-01
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| Series: | Fundamental Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2667325821000625 |
| _version_ | 1797976287821692928 |
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| author | Jiang Liu Bo Meng Alexandre.J. Poulain Qiyi Meng Xinbin Feng |
| author_facet | Jiang Liu Bo Meng Alexandre.J. Poulain Qiyi Meng Xinbin Feng |
| author_sort | Jiang Liu |
| collection | DOAJ |
| description | Methylmercury (MeHg) contaminated rice is a global issue, particularly in mercury-polluted areas, posing a potential threat to human health. The sources and transformations of mercury (Hg) species in rice are critical points that are not yet fully understood. In this study, field experimental pots together with a stable Hg isotope tracing technique were used to provide direct evidence of the sources and transformations of Hg species in rice plants. Enriched inorganic Hg (IHg) isotope (200Hg(NO3)2) was spiked into paddy soils, and the concentrations of inorganic Hg tracer (I200Hg), MeHg tracer (Me200Hg), and ambient Hg species (IHg and MeHg) were measured in the tissues of rice plants and their corresponding soil samples during the rice growing season. Here, we show that, in addition to the atmosphere, the soil is an important source of IHg to rice grains and was previously largely underestimated. We also show that MeHg is formed in paddy soil via microbial IHg methylation, absorbed through the rice root, translocated from the root to above-ground parts, and finally accumulated in rice grains. Although in vivo methylation of IHg in rice plants is unlikely to occur during the rice growing season, we observed in vivo demethylation of MeHg in the above-ground parts of rice plants, possibly via photolytic demethylation. Promoting in vivo demethylation of MeHg may be an effective approach to mitigate MeHg accumulation in rice grains. |
| first_indexed | 2024-04-11T04:48:36Z |
| format | Article |
| id | doaj.art-35a0f15eb9bf4e3685216b488e74c97a |
| institution | Directory Open Access Journal |
| issn | 2667-3258 |
| language | English |
| last_indexed | 2024-04-11T04:48:36Z |
| publishDate | 2021-05-01 |
| publisher | KeAi Communications Co. Ltd. |
| record_format | Article |
| series | Fundamental Research |
| spelling | doaj.art-35a0f15eb9bf4e3685216b488e74c97a2022-12-27T04:41:54ZengKeAi Communications Co. Ltd.Fundamental Research2667-32582021-05-0113259268Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining areaJiang Liu0Bo Meng1Alexandre.J. Poulain2Qiyi Meng3Xinbin Feng4State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, ChinaState Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China; Corresponding author.Biology Department, University of Ottawa, 30 Marie Curie, Ottawa ON K1N 6N5, CanadaState Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, ChinaState Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China; Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China; Corresponding author.Methylmercury (MeHg) contaminated rice is a global issue, particularly in mercury-polluted areas, posing a potential threat to human health. The sources and transformations of mercury (Hg) species in rice are critical points that are not yet fully understood. In this study, field experimental pots together with a stable Hg isotope tracing technique were used to provide direct evidence of the sources and transformations of Hg species in rice plants. Enriched inorganic Hg (IHg) isotope (200Hg(NO3)2) was spiked into paddy soils, and the concentrations of inorganic Hg tracer (I200Hg), MeHg tracer (Me200Hg), and ambient Hg species (IHg and MeHg) were measured in the tissues of rice plants and their corresponding soil samples during the rice growing season. Here, we show that, in addition to the atmosphere, the soil is an important source of IHg to rice grains and was previously largely underestimated. We also show that MeHg is formed in paddy soil via microbial IHg methylation, absorbed through the rice root, translocated from the root to above-ground parts, and finally accumulated in rice grains. Although in vivo methylation of IHg in rice plants is unlikely to occur during the rice growing season, we observed in vivo demethylation of MeHg in the above-ground parts of rice plants, possibly via photolytic demethylation. Promoting in vivo demethylation of MeHg may be an effective approach to mitigate MeHg accumulation in rice grains.http://www.sciencedirect.com/science/article/pii/S2667325821000625RiceHg isotope tracerSourceTranslocationMethylation/demethylation |
| spellingShingle | Jiang Liu Bo Meng Alexandre.J. Poulain Qiyi Meng Xinbin Feng Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area Fundamental Research Rice Hg isotope tracer Source Translocation Methylation/demethylation |
| title | Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area |
| title_full | Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area |
| title_fullStr | Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area |
| title_full_unstemmed | Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area |
| title_short | Stable isotope tracers identify sources and transformations of mercury in rice (Oryza sativa L.) growing in a mercury mining area |
| title_sort | stable isotope tracers identify sources and transformations of mercury in rice oryza sativa l growing in a mercury mining area |
| topic | Rice Hg isotope tracer Source Translocation Methylation/demethylation |
| url | http://www.sciencedirect.com/science/article/pii/S2667325821000625 |
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