Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation

Luo, Huimin; Yin, Xiangping; Jubb, Aaron M.; Chen, Hongmei; Xia, Lu; Zhang, Weihua; Lin, Hui; Yu, Han‐Qing; Liang, Liyuan; Sheng, Guo‐Ping; Gu, Baohua

doi:10.1016/j.envpol.2016.10.099

Cited by 57 publications

(33 citation statements)

References 49 publications

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“…The effects of cultivation ages on soil properties and HM concentration may suggest potential association between them. Previous work revealed that HM concentrations and bioavailability are closely related to soil physicochemical properties, e.g., OM contents (Luo et al, 2017), pH (Jackson et al, 1993;Liu et al, 2013) and nutrient concentrations. The effect of soil properties on HM concentrations in soil could result from the biogeochemical processess in soil including adsorption, precipitation and complexation reaction with soil components (Wang et al, 2015a;2015b;.…”

Section: Correlation Between Soil Properties and Hmsmentioning

confidence: 99%

Cultivation Ages Effect on Soil Physicochemical Properties and Heavy Metal Accumulation in Greenhouse Soils

et al. 2018

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The intensive management practices in greenhouse production may alter the soil physicochemical properties and contribute to the accumulation of heavy metals (HMs). To determine the HM concentrations in vegetable soil in relation to soil physicochemical properties and cultivation age, we conducted a soil survey for typical greenhouse soils in Shouguang, China. The results indicated that Cd is a major HM pollutant in the tested soils, as the only HM element exceeding the allowed limit for vegetable soil. The surveyed data was analyzed with regression analysis, correlation analysis and canonical correspondence analysis (CCA). A positive correlation is observed between HM pollution level and cultivation age. CCA results suggest that the HM pollution level and distribution in soil are significantly affected by soil physicochemical properties, which was a function of years of cultivation as revealed by regression analysis. In summary, cultivation age is an important factor to affect soil physicochemical properties (organic matter and inorganic nutrients) as well as HM contamination.

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Section: Correlation Between Soil Properties and Hmsmentioning

confidence: 99%

Cultivation Ages Effect on Soil Physicochemical Properties and Heavy Metal Accumulation in Greenhouse Soils

et al. 2018

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“…Therefore, the DOM increased concentration may inhibit Hg adsorption dramatically. In addition to DOM stabilizing Hg in dissolved phase, the formation of β-HgS particles from Hg 2 + interacting with DOM was found in others [49,50]. The particle size of β-HgS nanoparticles was around 3-5 nm reported by Manceau et al [50].…”

Section: "Hg + Dom" Conditionmentioning

confidence: 81%

Influence of sulfide, chloride and dissolved organic matter on mercury adsorption by activated carbon in aqueous system

Chen

Ch’ng

et al. 2020

Sustain Environ Res

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Using activated carbon (AC) as thin layer capping to reduce mercury (Hg) released from contaminated sediment is a feasible and durable remediation approach. However, several aqueous factors could greatly affect the Hg fate in the aquatic system. This study thus intends to clarify the influences on Hg adsorption by AC with the presence of sulfide, dissolved organic matter (DOM), and chloride. The lab-scale batch experiments were divided into two parts, including understanding (1) AC adsorption performance and (2) Hg distribution in different phases by operational definition method. Results showed that the Hg adsorption rate by AC was various with the presence of sulfide, chloride, and DOM (from fast to slow). Hg adsorption might be directly bonded to AC with Hg-Cl and Hg-DOM complexes and the rate was mainly controlled by intraparticle diffusion. In contrast, “Hg + sulfide” result was better described by pseudo-second order kinetics. The Hg removal efficiency was 92–95% with the presence of 0–400 mM chloride and approximately 65–75% in the “Hg + sulfide” condition. Among the removed Hg, 24–29% was formed into aqueous-phase particles and about 30% Hg was adsorbed on AC with 2–20 μM sulfide. Increasing DOM concentration resulted in more dissolved Hg. The proportion of dissolved Hg increased 31% by increasing DOM concentration from 0.25 to 20 mg C L− 1. Simultaneously, the proportion of adsorbed Hg by AC decreased by 47%. Overall, the presence of chloride increases the Hg adsorption by AC. In contrast, the presence of sulfide and DOM causes a negative effect on AC adsorption.

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“…11,17,19,46 Photochemical processes may produce inert Hg products (nonreducing or slower reducing components), resulting in differences between biological and photochemical reduction. 47,48 The fundamental mechanisms involved in the biological reduction process remain poorly understood. We estimated the contributions of microalgae, bacteria, SPM, and DOM/extracellular substances to dark Hg 2+ reduction in natural seawater.…”

Section: ■ Discussionmentioning

confidence: 99%

Dark Reduction of Mercury by Microalgae-Associated Aerobic Bacteria in Marine Environments

Zhang

Liu

et al. 2021

Environ. Sci. Technol.

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Redox transformation of mercury (Hg) is critical for Hg exchange at the air−sea interface and it can also affect the methylation of Hg in marine environments. However, the contributions of microalgae and aerobic bacteria in oxic seawater to Hg 2+ reduction are largely unknown. Here, we studied the reduction of Hg 2+ mediated by microalgae and aerobic bacteria in surface marine water and microalgae cultures under dark and sunlight conditions. The comparable reduction rates of Hg 2+ with and without light suggest that dark reduction by biological processes is as important as photochemical reduction in the tested surface marine water and microalgae cultures. The contributions of microalgae, associated free-living aerobic bacteria, and extracellular substances to dark reduction were distinguished and quantified in 7 model microalgae cultures, demonstrating that the associated aerobic bacteria are directly involved in dark Hg 2+ reduction. The aerobic bacteria in the microalgae cultures were isolated and a rapid dark reduction of Hg 2+ followed by a decrease of Hg 0 was observed. The reduction of Hg 2+ and re-oxidation of Hg 0 were demonstrated in aerobic bacteria Alteromonas spp. using double isotope tracing ( 199 Hg 2+ and 201 Hg 0 ). These findings highlight the importance of algae-associated aerobic bacteria in Hg transformation in oxic marine water.

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Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation

Cited by 57 publications

References 49 publications

Cultivation Ages Effect on Soil Physicochemical Properties and Heavy Metal Accumulation in Greenhouse Soils

Cultivation Ages Effect on Soil Physicochemical Properties and Heavy Metal Accumulation in Greenhouse Soils

Influence of sulfide, chloride and dissolved organic matter on mercury adsorption by activated carbon in aqueous system

Dark Reduction of Mercury by Microalgae-Associated Aerobic Bacteria in Marine Environments

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