JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Ji Chen,Gongren Hu,Jiang Liu,Alexandre J. Poulain,Qiang Pu,Rong Huang,Bo Meng,Xinbin Feng
The production of methylmercury (MeHg) in flooded paddy fields determines its accumulation in rice grains; this, in turn, results in MeHg exposure risks for not only rice-eating humans but also wildlife. Nitrogen (N) fertilizers have been widely applied in rice cultivation fields to supply essential nutrients. However, the effects of N fertilizer addition on mercury (Hg) transformations are not unclear. This limits our understanding of MeHg formation in rice paddy ecosystems. In this study, we spiked three Hg tracers ( 200 Hg II , Me 198 Hg, and 202 Hg 0 ) in paddy slurries fertilized with urea, ammonium, and nitrate. The influences of N fertilization on Hg methylation, demethylation, and reduction and the underlying mechanisms were elucidated. The results revealed that dissimilatory nitrate reduction was the dominant process in the incubated paddy slurries. Nitrate addition inhibited Hg II reduction, Hg II methylation, and MeHg demethylation. Competition between nitrates and other electron acceptors (e.g., Hg II , sulfate, or carbon dioxide) under dark conditions was the mechanism underlying nitrate-regulated Hg transformation. Ammonium and urea additions promoted Hg II reduction, and anaerobic ammonium oxidation coupled with Hg II reduction (Hgammox) was likely the reason. This work highlighted that nitrate addition not only inhibited Hg II methylation but also reduced the demethylation of MeHg and therefore may generate more accumulation of MeHg in the incubated paddy slurries. Findings from this study link the biogeochemical cycling of N and Hg and provide crucial knowledge for assessing Hg risks in intermittently flooded wetland ecosystems .
研究领域:
环境科学
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土壤学
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产品关联
DOI
PubMed
高影响因子
FUEL
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2014
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IF 3.406
Mingyang Sun,Zimo Lou,Guanghuan Cheng,Shams Ali Baig,Li Fang,Xiaoxin Zhou,Yixia Shen,Xinhua Xu
Wet flue gas desulfurization (WFGD) system has been increasingly recognized to be effective in Hg removal. But the generated secondary pollution due to Hg re-emission from desulfurization solutions or solid byproducts has received researchers’ attention. In this paper, the distribution of captured Hg 2+ (L) in the simulated WFGD slurry was studied as a function of various environmental factors. Experimental results indicated that the pH value had a strong effect on Hg 2+ reduction but had negligible influence on the Hg 2+ retention by the grained fraction of gypsum. Increasing in pH value resulted in higher Hg 2+ reduction and over 46% of Hg 2+ was found to be reduced into Hg 0 at pH 5.0. Besides, increased slurry temperature also promoted the Hg 2+ reduction and Hg 0 re-emission as well as the Hg 2+ retention efficiency by gypsum. Other factors including S (IV), Cl − and NO 3 − concentration was found to inhibit Hg 2+ transformation into Hg 0 but slightly promoted the Hg 2+ retained in gypsum. Moreover, the addition of sodium sulfide (Na 2 S), 2,4,6-trimercaptotiazine, trisodium salt nonahydrate (TMT), and sodium dithiocarbamate (DTCR) prevented the Hg 2+ reduction and precipitated out as insoluble HgS, Hg 3 (TMT) 2 and Hg(DTCR) 2 on gypsum. The findings presented in this study could provide theoretical basis for Hg removal in coal-fired power plants.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
GEOCHIMICA ET COSMOCHIMICA ACTA
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2025
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IF 5
Qingyi Cao,Junyi Liu,Jicheng Xia,Jen-How Huang,Susan Glasauer,Haiyan Hu,Xinbin Feng
Mineral-associated mercury (Hg), predominantly as mercury sulfide (HgS), represents the largest environmental Hg reservoir and is typically considered immobile and inert. Here, we reveal a novel microbe-mediated mechanism for the bioleaching of crystalline HgS via cysteine secreted by microorganisms. Hg-resistant bacterial strains Arthrobacter sp. WS-B1, Massilia sp. WS-B3, and Serratia sp. WS-B5, isolated from Wanshan mining soils in China, were found to secrete cysteine, which promotes the disintegration of crystalline HgS into HgS nanoparticles (HgSNPs), dissolved Hg, and ultimately volatile Hg(0). Utilizing transmission electron microscopy with energy-dispersive X-ray spectroscopy, HgS breakdown was evidenced through the detection of HgSNPs and a broadened Hg:S ratio range from 1.08 ± 0.05 to 0.33–1.58. Time-of-flight secondary ion mass spectrometry analysis revealed the co-localisation of C 3 H 7 NO 2 S and Hg, indicating Hg–cysteine complexation. These complexes inhibited Hg precipitation, maintaining its bioavailability for crops, while also enabling photoreduction via ligand-to-metal charge transfer upon irradiation to detoxify soil Hg. This study sheds light on the microbial transformation of crystalline HgS, the formation pathways of HgSNPs in nature, and the enhanced bioavailability of Hg previously considered inert
研究领域:
环境微生物学
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地球化学
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环境科学
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生物地球化学
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微生物生态学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）