To explore the possibility of using chemical extraction methods to predict phytoavailability/bioaccumulation of soil-bound MeHg, MeHg extractions by three widely-used extractants (CaCl2, DTPA, and (NH4)2S2O3) were compared with MeHg accumulation in rice grains. Despite of variations in characteristics of different soils, MeHg extracted by (NH4)2S2O3 (highly affinitive to MeHg) correlated well with grain MeHg levels. Thus (NH4)2S2O3 extraction, solubilizing not only weakly-bound and but also strongly-bound MeHg, may provide a measure of 'phytoavailable MeHg pool' for rice plants. Besides, a better prediction of grain MeHg levels was obtained when growing condition of rice plants was also considered. However, MeHg extracted by CaCl2 or DTPA, possibly quantifying 'exchangeable MeHg pool' or 'weakly-complexed MeHg pool' in soils, may not indicate phytoavailable MeHg or predict grain MeHg levels. Our results provided the possibility of predicting MeHg phytoavailability/bioaccumulation by (NH4)2S2O3 extraction, which could be useful in screening soils for rice cultivation in contaminated areas.
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http://dx.doi.org/10.1016/j.envpol.2015.01.015 | DOI Listing |
Sci Total Environ
January 2025
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012 Beijing, China. Electronic address:
Methylmercury (MeHg) is a neurotoxicant with adverse effects on visual systems from fish to man. Clinical signs of visual deficits including color-vision alterations, visual field constriction and blindness have been frequently identified in patients and affected animals following acute and chronic exposure to MeHg. However, it is still unclear whether MeHg causes developmental defects in the eye.
View Article and Find Full Text PDFEnviron Pollut
December 2024
College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China; Faculty of Architecture and Engineering, Guizhou Polytechnic of Construction, Guiyang, 551400, China.
Although the use of foliar spraying with organic matter has been extensively studied and applied to reduce heavy metals in plants, research on its application for reducing mercury (Hg) accumulation in plants, particularly the more toxic methylmercury (MeHg), remains scarce. Furthermore, previous researches on the barrier mechanisms of foliar spraying primarily concentrated on the effects of spraying agents on plant physiological and biochemical indicators, with limited focus on their impacts on soil environment. Herein, the dynamic effects and mechanisms of organic foliar spraying materials, including earthworm liquid fertilizer (ELF), Tween 80 (T80), and citric acid (CA), on soil Hg methylation and accumulation in lettuce were investigated using pot experiment.
View Article and Find Full Text PDFEnviron Int
December 2024
National Institute for Minamata Disease, Minamata, Kumamoto 867-0008, Japan.
J Environ Manage
December 2024
Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China.
Returning raw straw to the soil can significantly elevate soil methylmercury (MeHg) and crop mercury (Hg) levels, underscoring the need to investigate safer approaches to straw utilization in mercury-contaminated regions. In this study, rice straw underwent anaerobic fermentation with the addition of sulfate, and the resulting fermentation products were utilized in a pot experiment involving water spinach to assess the impact of anaerobically fermented straw return on soil Hg methylation and its bioaccumulation. Findings revealed that the addition of sulfate during straw fermentation markedly increased the fermentation degree of the products, and sulfate was converted into organic sulfur-containing ligands that can functionalize the fermentation residuals.
View Article and Find Full Text PDFEnviron Res
December 2024
College of Resources and Environment, Southwest University, Chongqing, 400715, China.
Sulfate-driven anaerobic oxidation of methane (AOM) and anaerobic digestion (AD) with municipal wastewater sludge containing heavy metals may provide favorable conditions for the biogeochemical transformation of mercury (Hg) by methanogens and methanotrophs. However, it remains largely unclear what Hg-methylators functioned and what role Methanosarcina played in these processes. Here, we performed sulfate-driven AOM following AD with Hg-containing wastewater sludge and investigated the role of microbes, especially Methanosarcina, in the biogeochemical transformation of Hg based on 16S rRNA amplicon and metatranscriptomic sequencing.
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