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Increased Methylmercury Accumulation in Rice after Straw Amendment.
- Source :
-
Environmental science & technology [Environ Sci Technol] 2019 Jun 04; Vol. 53 (11), pp. 6144-6153. Date of Electronic Publication: 2019 Apr 24. - Publication Year :
- 2019
-
Abstract
- Consumption of rice has been shown to be an important route of dietary exposure to methylmercury (MeHg, a neurotoxin) for Asians having a low fish but high rice diet. Therefore, factors that increase MeHg production and bioaccumulation in soil-rice systems, could enhance the risk of MeHg exposure. On the basis of a national-scale survey in China (64 sites in 12 provinces) and rice cultivation experiments, we report that straw amendment, a globally prevalent farming practice, could increase MeHg concentrations in paddy soils (11-1043%) and rice grains (95%). By carrying out a series of batch incubation, seedling uptake and sand culture experiments, we demonstrate that these increases could be attributed to (1) enhanced abundances/activities of microbial methylators and the transformation of refractory HgS to organic matter-complexed Hg, facilitating microbial Hg methylation in soils; (2) enhanced MeHg mobility, and increased root lengths (35-41%) and tip numbers (60-105%), increasing MeHg uptake by rice roots; and (3) enhanced MeHg translocation to rice grains from other tissues. Results of this study emphasize fresh organic matter-enhanced MeHg production and bioaccumulation, and highlight the increased risk of MeHg after straw amendment and thus the need for new policies concerning straw management.
- Subjects :
- China
Soil
Mercury
Methylmercury Compounds
Oryza
Soil Pollutants
Subjects
Details
- Language :
- English
- ISSN :
- 1520-5851
- Volume :
- 53
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Environmental science & technology
- Publication Type :
- Academic Journal
- Accession number :
- 30983351
- Full Text :
- https://doi.org/10.1021/acs.est.8b07145