Influence of rice straw amendment on mercury methylation and nitrification in paddy soils

Liu, Yurong; Dong, Jixin; Han, Li‐Li; Zheng, Yuqi; He, Ji‐Zheng

doi:10.1016/j.envpol.2015.11.023

Cited by 62 publications

(21 citation statements)

References 51 publications

(58 reference statements)

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“…Although there have been several recent studies that focused on contaminated sites (Duran et al 2008;Gray and Hines 2009;Huguet et al 2010;Avramescu et al 2011;Hines et al 2012;Marvin-DiPasquale et al 2014;Windham-Myers et al 2014a, 2014b, 2014cEckley et al 2015;Figueiredo et al 2016;Liu et al 2016), these are beyond the scope of this paper; this review focuses exclusively on non-polluted aquatic systems. Recent reviews regarding both Hg methylation and demethylation focused on assessing the bioavailability of particular Hg species and the use of stable isotope techniques in methylation studies (Li and Cai 2013), the molecular mechanisms of mercury uptake and methylation (Hsu-Kim et al 2013b), and Hg cycling in Arctic (Douglas et al 2012;Braune et al 2015) and coastal marine and estuarine (Merritt and Amirbahman 2009) systems.…”

Section: Introductionmentioning

confidence: 99%

Recent advances in the study of mercury methylation in aquatic systems

Paranjape

Hall

2017

FACETS

117

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With increasing input of neurotoxic mercury to environments as a result of anthropogenic activity, it has become imperative to examine how mercury may enter biotic systems through its methylation to bioavailable forms in aquatic environments. Recent development of stable isotope-based methods in methylation studies has enabled a better understanding of the factors controlling methylation in aquatic systems. In addition, the identification and tracking of the hgcAB gene cluster, which is necessary for methylation, has broadened the range of known methylators and methylation-conducive environments. Study of abiotic factors in methylation with new molecular methods (the use of stable isotopes and genomic methods) has helped elucidate the confounding influences of many environmental factors, as these methods enable the examination of their direct effects instead of merely correlative observations. Such developments will be helpful in the finer characterization of mercury biogeochemical cycles, which will enable better predictions of the potential effects of climate change on mercury methylation in aquatic systems and, by extension, the threat this may pose to biota.

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Section: Introductionmentioning

confidence: 99%

Recent advances in the study of mercury methylation in aquatic systems

Paranjape

Hall

2017

FACETS

117

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“…Several features of rice paddies make them conducive sites for methylation, including flooded conditions, anoxic soils, and high primary productivity, which leads to high amounts of organic matter . Rice paddy cultivation in this part of China involves rice straw amendment, whereby the stems and roots from the older plants are allowed to decay into the soil; such practices ensure high organic content and may also acidify soils .…”

Section: Discussionmentioning

confidence: 99%

“…Environ Toxicol Chem 36, 2017 roots from the older plants are allowed to decay into the soil; such practices ensure high organic content and may also acidify soils [25]. These soil conditions in rice paddies may make the earthworms important biomagnifiers of MeHg.…”

Section: Total Hg and Mehg In Earthwormsmentioning

confidence: 99%

Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil

Abeysinghe

Yang

Goodale

et al. 2016

Enviro Toxic and Chemistry

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Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia. Environ Toxicol Chem 2017;36:1202-1210. © 2016 SETAC.

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“…S‐II and S‐III were raw, acidic soils (especially S‐III) with relatively low CEC and organic matter content. An HgCl 2 solution was used to dose the four soil samples to obtain an Hg content of 100 mg kg −1 (dry weight, DW), an amount chosen based on the reported Hg contents observed in Hg‐contaminated soils, which range from 0.5 to 280 mg kg −1 recorded in the literature . S‐V had a neutral pH and exhibited the largest d 50 among the tested soils, as well as exhibiting a significantly lower CEC and organic matter content compared with the other samples.…”

Section: Methodsmentioning

confidence: 99%

Isolation of the Hg(II)‐volatilizing Bacillus sp. strain DC‐B2 and its potential to remediate Hg(II)‐contaminated soils

Chen

Dong

Shen

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Mercury (Hg) contamination is a major global environmental problem, and its remediation using environmentally friendly biotechnologies has attracted increasing attention. In this study, an Hg(II)‐resistant bacterial strain, Bacillus sp. DC‐B2, was isolated from a metal‐contaminated site, and its ability to remediate five types of Hg‐contaminated soils was investigated. RESULTS The isolate DC‐B2 showed strong resistance to multiple metals and volatilized 91.6% of the Hg(II) in a culture with an initial Hg(II) concentration of 10 mg L−1 within 8 h. Microcosm experiments showed that the addition of DC‐B2 culture improved Hg(II) removal by 11.7–17.2% from four artificially Hg(II)‐spiked soil samples with initial Hg contents of approximately 100 mg kg−1 after incubating for 30 days under flooded conditions compared to the control treatment. For the field‐contaminated farmland soil containing 2.50 mg Hg kg−1, an Hg(II) elimination rate of 82.1% was achieved within 30 days with the DC‐B2 inoculation, relative to the 34.1% elimination rate observed for the uninoculated control. The amendment of peptone broth slightly inhibited Hg removal (2.2–8.7%). The remediation effectiveness was verified by observations of longer root and shoot lengths of lettuce plants grown in treated soils compared to those grown in the control soil. CONCLUSION The isolate Bacillus sp. DC‐B2 shows great potential to be developed as a bioagent for effective bioremediation of Hg‐contaminated soils. © 2018 Society of Chemical Industry

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Influence of rice straw amendment on mercury methylation and nitrification in paddy soils

Cited by 62 publications

References 51 publications

Recent advances in the study of mercury methylation in aquatic systems

Recent advances in the study of mercury methylation in aquatic systems

Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil

Isolation of the Hg(II)‐volatilizing Bacillus sp. strain DC‐B2 and its potential to remediate Hg(II)‐contaminated soils

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