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Zhu S, Yang C, Chen H, Wang Y, Li J, Zhang R, Yang Y, Zhang C, Wang D. Organic Carbon Controls Mercury Distribution and Storage in the Surface Soils of the Water-Level-Fluctuation Zone in the Three Gorges Reservoir Region, China. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3681. [PMID: 36834375 PMCID: PMC9968128 DOI: 10.3390/ijerph20043681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
The particular condition of the water-level-fluctuation zone (WLFZ) in the Three Gorges Reservoir (TGR), the largest hydroelectric reservoir in China, raises great concerns about mercury (Hg) contamination and ecological risk. In addition, previous research found that soil organic carbon (SOC) plays an essential role in controlling Hg distribution and speciation. However, there is minimal information on the Hg storage distribution and their relationships with SOC in the WLFZ in TGR. This study investigated Hg distribution, storage, and their relationships with SOC in the surface soils in WLFZ. The results showed that the total Hg (THg) content in the surface soils ranged from 18.40 to 218.50 ng g-1, with an average value of 78.17 ± 41.92 ng g-1. About 89% of samples had THg content above the background value in Chongqing, showing specific enrichment of Hg in WLFZ due to contamination in the TGR. The surface soils have low SOC, with an average value of 8.10 ± 3.90 g kg-1. Moreover, THg content showed consistent distribution with the SOC in WLFZ, with a significantly positive correlation (R = 0.52, p < 0.01, n = 242). THg storage (201.82 ± 103.46 g ha-1) in the surface soils was also significantly positively correlated with the SOC storage (R = 0.47, p < 0.01, n = 242). The reduced SOC sequestration, due to the periodical alternative "flooding-draining" and frequent reclamation and utilization of WLFZ, decreased the Hg adsorption in soil. Those might result in the re-release of Hg into waters when WLFZ is flooded. Therefore, more attention should be directed towards Hg cycling and the consequent environmental risks in the TGR region.
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Affiliation(s)
- Sihua Zhu
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Caiyun Yang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Hong Chen
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Yongmin Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Jieqin Li
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Ruixi Zhang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Yu Yang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Cheng Zhang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Dingyong Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Southwest University, Chongqing 400716, China
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Shi Z, Wen M, Zhang J, Tang Z, Wang C. Effect of phenanthrene on the biological characteristics of earthworm casts and their relationships with digestive and anti-oxidative systems. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 193:110359. [PMID: 32097786 DOI: 10.1016/j.ecoenv.2020.110359] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/16/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
Earthworms as ecosystem engineers partially improve soil properties by egesting casts. Our previous study confirmed that soil pollution affects the physico-chemical properties of earthworm casts. It is still unclear whether the biological properties (e.g. cellulase, urease, and acid and alkaline phosphatase activities, as well as microbial biomass carbon) of casts are affected by foreign substances in soil. The present study aimed to investigate the effect of phenanthrene (PHE) on the biological characteristics of earthworm (Eisenia fetida) casts. Furthermore, correlations between cast properties and the digestive and antioxidant systems were explored by the determination of digestive enzyme (urease, protease, acid and alkaline phosphatase) activities, antioxidant indexes [superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)], as well as malondialdehyde (MDA) content. Exposure at a range of PHE doses (0, 2, 5, 10, and 20 mg kg-1) for 15 d resulted in the following observations: (1) Compared with urease, as well as acid and alkaline phosphatase activities, cellulase activities in both soil and casts were sensitive to PHE, and could potentially act as biomarkers to provide early-warning signals for soil pollution. (2) Microbial biomass carbon in casts was modified, but with no clear pattern. (3) Cellulase and POD activities, as well as MDA content in earthworms, increased with elevated exposure to PHE in soil. Protease, SOD, and CAT activities exhibited a biphasic dose response to PHE, while acid and alkaline phosphatase activities were inhibited under treatment conditions. (4) Correlation analysis suggested that microbial biomass carbon in casts significantly and positively correlated with cellulase and acid phosphatase activities of earthworms, but negatively correlated with protease activities. A significant but weak negative correlation between alkaline phosphatase activities in casts and POD activities was also observed. Based on these results, we concluded that PHE content in soil modified some biological properties of casts, by partially affecting the earthworm's digestive and antioxidant systems. This study advances our knowledge of earthworm ecology in polluted soil by providing a better understanding of their ecological functions.
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Affiliation(s)
- Zhiming Shi
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan, 030006, PR China; Shaanxi Key Laboratory of Land Consolidation, Xi'an, 710064, PR China; Shanxi Sino-Environmental Hongda Monitoring Technology Co. Ltd., Taiyuan, 030032, PR China.
| | - Mei Wen
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan, 030006, PR China
| | - Juan Zhang
- Shanxi Sino-Environmental Hongda Monitoring Technology Co. Ltd., Taiyuan, 030032, PR China
| | - Zhiwen Tang
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan, 030006, PR China
| | - Congying Wang
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan, 030006, PR China; Shaanxi Key Laboratory of Land Consolidation, Xi'an, 710064, PR China; Shanxi Sino-Environmental Hongda Monitoring Technology Co. Ltd., Taiyuan, 030032, PR China.
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Ray S, Gautam A, Ray A, Das S, Ray M. Analysis of oxidative stress and cellular aggregation in the coelomocytes of earthworms collected from metal contaminated sites of industrial and agricultural soils of West Bengal, India. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:22625-22640. [PMID: 31168715 DOI: 10.1007/s11356-019-05438-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
Endogeic earthworm Metaphire posthuma (Valliant, 1868) is a common biological component of the tropical soil of India and other countries. The species is reported to influence fertility and porosity of soil and bear a high composting potential. Intensive agricultural, industrial, and mining activities increase the amount of toxic metals in soil causing physiological adversity in earthworm and other biotic components in soil. Coelomocytes, the chief immunoeffector cells of earthworm, perform diverse physiological functions under the challenge of toxins and pathogens. The experimental earthworms collected separately from soils with agricultural and tannery activities were subjected to quantitation of prooxidation and antioxidation parameters for estimation of oxidative stress. Total count, cellular aggregation, generation of reactive oxygen species (ROS), superoxide anion, nitric oxide, activities of phenoloxidase, superoxide dismutase, catalase and glutathione-s-transferase, and amount of total protein were estimated in the coelomocytes of M. posthuma as experimental end points of toxicity screening. Concentrations of cadmium, chromium, lead, and mercury were determined in the soil samples to assess the degree of toxic contamination. The increase in the amount of prooxidants and decrease in the activities of antioxidant enzymes indicated the signs of oxidative stress in the coelomocytes of the organism. Aggregation of circulating coelomocytes is considered as an immune response involved in pathogen encapsulation response as reported in many invertebrates. Decrease in coelomocyte aggregation in earthworm collected from contaminated sites suggested a state of inappropriate shift of the innate immune status. Toxin-induced oxidative stress and reductions in cell aggregation response are the signs of immunocompromisation of M. posthuma. Present findings bear a prospect of this experimental species as an indicator of soil pollution.
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Affiliation(s)
- Sajal Ray
- Aquatic Toxicology Laboratory, Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700019, India.
| | - Arunodaya Gautam
- Aquatic Toxicology Laboratory, Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700019, India
| | - Abhishek Ray
- Aquatic Toxicology Laboratory, Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700019, India
| | - Subhadeep Das
- Chemical Signal and Lipidomics Laboratory, Department of Botany, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, West Bengal, 700019, India
| | - Mitali Ray
- Aquatic Toxicology Laboratory, Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, West Bengal, 700019, India
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Shi Z, Tang Z, Wang C. Effect of phenanthrene on the physicochemical properties of earthworm casts in soil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 168:348-355. [PMID: 30391839 DOI: 10.1016/j.ecoenv.2018.10.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 10/07/2018] [Accepted: 10/09/2018] [Indexed: 06/08/2023]
Abstract
Earthworms have been widely studied as bioindicators of soil health for their important role in sustaining soil structure and functions. Many soil contaminants such as phenanthrene have been confirmed to exert adverse effects on earthworms' growth, reproduction, behaviors and biochemical conditions. However, their effects on the properties of earthworm casts have been little studied. In the present study, the effect of different doses of phenanthrene (PHE) (0, 2, 5, 10, 20 mg/kg) on the six physicochemical properties and Fourier transform infrared spectroscopy (FTIR) spectra characteristics of earthworm casts was assessed in artificial soil in a laboratory. 1) Residual concentration of PHE in soils and casts increased with the increasing exposure concentrations and followed the order of casts > soil, concluding that Kow values are the important factor affecting the distribution of hydrophobic organic contaminants (HOCs) in soil and casts; 2) Earthworms produced casts with improved total organic carbon (TOC) (15-19%), NH4+-N (550-800%), total available phosphorus (TAP) (300-450%), cation exchange capacity (CEC) (about 15%) and available potassium (AK) (7-12.6%) compared to that in unpolluted soil, indicating that earthworms still have the ability to play the role of ecological engineers even in polluted soil; 3) The sensitivity of different properties of casts to phenanthrene varies, the order of sensitivity being (most sensitive first) NH4+-N ( triggered as 2 mg/kg of exposure concentrations) > AK (5 mg/kg) > Olsen-P (10 mg/kg) > TOC = pH= CEC (no response within the range of exposure concentrations). NH4+-N content in casts shows a clear dose-response relationship when the exposure exceeds 2 mg/kg, indicating that the index might be a potential sensitive biomarker to provide early warning for soil pollution. 4) FTIR spectra showed that the constitution of casts from earthworms in PHE-spiked soil was not significantly alternated. However, FTIR spectra revealed that the concentrations of C-O of polysaccharide in casts increased with the elevated exposure concentrations, indicating that intensities of C-O of polysaccharide at 1032 cm-1 of casts might be also a potential biomarker for the early-warning of soil pollution. This study advances the knowledge of earthworm ecology in polluted soil, and further extends the scope of earthworm casts as a potential biomarker in soil pollution assessment.
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Affiliation(s)
- Zhiming Shi
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan 030006, PR China; Shaanxi Key Laboratory of Land Consolidation, Xi'an 710064, PR China.
| | - Zhiwen Tang
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan 030006, PR China.
| | - Congying Wang
- College of Environmental and Resource Sciences, Shanxi University, Taiyuan 030006, PR China; Shaanxi Key Laboratory of Land Consolidation, Xi'an 710064, PR China.
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Yang J, Takaoka M, Sano A, Matsuyama A, Yanase R. Vertical Distribution of Total Mercury and Mercury Methylation in a Landfill Site in Japan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15061252. [PMID: 29899229 PMCID: PMC6025181 DOI: 10.3390/ijerph15061252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/05/2018] [Accepted: 06/08/2018] [Indexed: 11/25/2022]
Abstract
Mercury is a neurotoxin, with certain organic forms of the element being particularly harmful to humans. The Minamata Convention was adopted to reduce the intentional use and emission of mercury. Because mercury is an element, it cannot be decomposed. Mercury-containing products and mercury used for various processes will eventually enter the waste stream, and landfill sites will become a mercury sink. While landfill sites can be a source of mercury pollution, the behavior of mercury in solid waste within a landfill site is still not fully understood. The purpose of this study was to determine the depth profile of mercury, the levels of methyl mercury (MeHg), and the factors controlling methylation in an old landfill site that received waste for over 30 years. Three sampling cores were selected, and boring sampling was conducted to a maximum depth of 18 m, which reached the bottom layer of the landfill. Total mercury (THg) and MeHg were measured in the samples to determine the characteristics of mercury at different depths. Bacterial species were identified by 16S rRNA amplification and sequencing, because the methylation process is promoted by a series of genes. It was found that the THg concentration was 19–975 ng/g, with a geometric mean of 298 ng/g, which was slightly less than the 400 ng/g concentration recorded 30 years previously. In some samples, MeHg accounted for up to 15–20% of THg, which is far greater than the general level in soils and sediments, although the source of MeHg was unclear. The genetic data indicated that hgcA was present mostly in the upper and lower layers of the three cores, merA was almost as much as hgcA, while the level of merB was hundreds of times less than those of the other two genes. A significant correlation was found between THg and MeHg, as well as between MeHg and MeHg/THg. In addition, a negative correlation was found between THg and merA. The coexistence of the three genes indicated that both methylation and demethylation processes could occur, but the lack of merB was a barrier for demethylation.
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Affiliation(s)
- Jing Yang
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C-kluster, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 6158540, Japan.
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C-kluster, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 6158540, Japan.
- Graduate School of Global Environmental Studies, Kyoto University, C-kluster, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 6158540, Japan.
| | - Akira Sano
- Graduate School of Global Environmental Studies, Kyoto University, C-kluster, Kyotodaigakukatsura, Nishikyo-ku, Kyoto 6158540, Japan.
| | - Akito Matsuyama
- National Institute for Minamata Disease, 4058-18 Hama, Minamata-City, Kumamoto 8670008, Japan.
| | - Ryuji Yanase
- Environmental Protection Center, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 8140180, Japan.
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In Situ Earthworm Breeding to Improve Soil Aggregation, Chemical Properties, and Enzyme Activity in Papayas. SUSTAINABILITY 2018. [DOI: 10.3390/su10041193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Buch AC, Brown GG, Correia MEF, Lourençato LF, Silva-Filho EV. Ecotoxicology of mercury in tropical forest soils: Impact on earthworms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 589:222-231. [PMID: 28258750 DOI: 10.1016/j.scitotenv.2017.02.150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/15/2017] [Accepted: 02/18/2017] [Indexed: 06/06/2023]
Abstract
Mercury (Hg) is one of the most toxic nonessential trace metals in the environment, with high persistence and bioaccumulation potential, and hence of serious concern to environmental quality and public health. Emitted to the atmosphere, this element can travel long distances, far from emission sources. Hg speciation can lead to Hg contamination of different ecosystem components, as well as biomagnification in trophic food webs. To evaluate the effects of atmospheric Hg deposition in tropical forests, we investigated Hg concentrations in earthworm tissues and soils of two Forest Conservation Units in State of Rio de Janeiro, Brazil. Next, we performed a laboratory study of the biological responses (cast analysis and behavioral, acute, chronic and bioaccumulation ecotoxicological tests) of two earthworms species (Pontoscolex corethrurus and Eisenia andrei) to Hg contamination in tropical artificial soil (TAS) and two natural forest soils (NS) spiked with increasing concentration of HgCl2. Field results showed Hg concentrations up to 13 times higher in earthworm tissues than in forest soils, while in the laboratory Hg accumulation after 91-days of exposure was 25 times greater in spiked-soils with 128mgHgkg-1 (dry wt) than in control (unspiked) soils. In all the toxicity tests P. corethrurus showed a higher adaptability or resistance to mercury than E. andrei. The role of earthworms as environmental bioremediators was confirmed in this study, showing their ability to greatly bioaccumulate trace metals while reducing Hg availability in feces.
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Affiliation(s)
- Andressa Cristhy Buch
- Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil.
| | - George Gardner Brown
- Embrapa Forestry, Estrada da Ribeira km. 111, C.P. 319, 83411-000 Colombo, PR, Brazil
| | | | - Lúcio Fábio Lourençato
- Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil
| | - Emmanoel Vieira Silva-Filho
- Department of Environmental Geochemistry, Fluminense Federal University, Outeiro São João Baptista, s/n., Centro, 24020-007 Niterói, RJ, Brazil
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Zhang W, Li J, Liu K, Lin K. The behavior and toxicological effects of decabromodiphenyl ether (BDE209) in a soil-earthworm system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 537:377-384. [PMID: 26282772 DOI: 10.1016/j.scitotenv.2015.08.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/16/2015] [Accepted: 08/04/2015] [Indexed: 06/04/2023]
Abstract
Decabromodiphenyl ether (BDE209) is easily absorbed by soil particles but barely degraded over time. Its potential ecological risk has received extensive attention. Here we supplemented natural soil with three different levels of BDE209 (1, 10 and 100 mg kg(-1) dry weight (i.e., dw)) to focus on the behavior and toxicological effects of BDE209 in a soil-earthworm system. Results demonstrated that earthworms accumulated BDE209 quickly, followed by biphasic elimination. The uptake rate constant (ku) values ranged from 0.156 to 0.232 mg soil kg(-1)worm d(-1), while the depuration rate (kd) values ranged from 0.228 to 0.239 d(-1). Biota-soil accumulation factor (BSAF) was also calculated in the present study, and the BSAF values for BDE209 ranged from 0.074 to 0.123. Throughout 28-d exposure, the concentrations of BDE209 among soil, worm casts and earthworms reached steady-state equilibrium. BDE209 content in worm casts might be a good indicator of actual concentration in soil. Neutral red retention time (NRRT) was also conducted to assess the lysosomal membrane stability, and it declined during the uptake phase when BDE209 gradually accumulated in earthworms, indicating a good dose-response relationship. These observations provide new insights into the potential ecological effects of BDE209 in a model soil-earthworm system.
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Affiliation(s)
- Wei Zhang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai 200237, China; School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Jing Li
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai 200237, China; School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Kou Liu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai 200237, China; School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Kuangfei Lin
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai 200237, China; School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
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Buch AC, Correia MEF, Teixeira DC, Silva-Filho EV. Characterization of soil fauna under the influence of mercury atmospheric deposition in Atlantic Forest, Rio de Janeiro, Brazil. J Environ Sci (China) 2015; 32:217-227. [PMID: 26040748 DOI: 10.1016/j.jes.2015.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/20/2014] [Accepted: 12/26/2014] [Indexed: 06/04/2023]
Abstract
The increasing levels of mercury (Hg) found in the atmosphere arising from anthropogenic sources, have been the object of great concern in the past two decades in industrialized countries. Brazil is the seventh country with the highest rate of mercury in the atmosphere. The major input of Hg to ecosystems is through atmospheric deposition (wet and dry), being transported in the atmosphere over large distances. The forest biomes are of strong importance in the atmosphere/soil cycling of elemental Hg through foliar uptake and subsequent transference to the soil through litter, playing an important role as sink of this element. Soil microarthropods are keys to understanding the soil ecosystem, and for such purpose were characterized by the soil fauna of two Units of Forest Conservation of the state of the Rio de Janeiro, inwhich one of the areas suffer quite interference from petrochemicals and industrial anthropogenic activities and other area almost exempts of these perturbations. The results showed that soil and litter of the Atlantic Forest in Brazil tend to stock high mercury concentrations, which could affect the abundance and richness of soil fauna, endangering its biodiversity and thereby the functioning of ecosystems.
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Affiliation(s)
- Andressa Cristhy Buch
- Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-007, Brazil.
| | | | - Daniel Cabral Teixeira
- Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, RJ 24020-007, Brazil
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Windmöller CC, Durão Júnior WA, de Oliveira A, do Valle CM. The redox processes in Hg-contaminated soils from Descoberto (Minas Gerais, Brazil): implications for the mercury cycle. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 112:201-211. [PMID: 25463872 DOI: 10.1016/j.ecoenv.2014.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 11/06/2014] [Accepted: 11/11/2014] [Indexed: 06/04/2023]
Abstract
Investigations of the redox process and chemical speciation of Hg(II) lead to a better understanding of biogeochemical processes controlling the transformation of Hg(II) into toxic and bioaccumulative monomethyl mercury, mainly in areas contaminated with Hg(0). This study investigates the speciation and redox processes of Hg in soil samples from a small area contaminated with Hg(0) as a result of gold mining activities in the rural municipality of Descoberto (Minas Gerais, Brazil). Soil samples were prepared by adding Hg(0) and HgCl2 separately to dry soil, and the Hg redox process was monitored using thermodesorption coupled to atomic absorption spectrometry. A portion of the Hg(0) added was volatilized (up to 37.4±2.0%) or oxidized (from 36±7% to 88±16%). A correlation with Mn suggests that this oxidation is favored, but many other factors must be evaluated, such as the presence of microorganisms and the types of organic matter present. The interaction of Hg with the matrix is suggested to involve Hg(II)-complexes formed with inorganic and organic sulfur ligands and/or nonspecific adsorption onto oxides of Fe, Al and/or Mn. The kinetics of the oxidation reaction was approximated for two first-order reactions; the faster reaction was attributed to the oxidation of Hg(0)/Hg(I), and the slower reaction corresponded to Hg(I)/Hg(II). The second stage was 43-139 times slower than the first. The samples spiked with Hg(II) showed low volatilization and a shifting of the signal of Hg(II) to lower temperatures. These results show that the extent, rate and type of redox process can be adverse in soils. Descoberto can serve as an example for areas contaminated with Hg(0).
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Affiliation(s)
- Cláudia C Windmöller
- Departamento de Química, ICEX, UFMG, Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil.
| | | | - Aline de Oliveira
- Departamento de Química, ICEX, UFMG, Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Cláudia M do Valle
- IFAM-Campus Manaus Centro, Av. Sete de setembro, 1975, 69020-120 Manaus, AM, Brazil
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Bavec S, Biester H, Gosar M. Urban sediment contamination in a former Hg mining district, Idrija, Slovenia. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2014; 36:427-439. [PMID: 24114255 DOI: 10.1007/s10653-013-9571-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/24/2013] [Indexed: 06/02/2023]
Abstract
Road sediments from gully pots of the drainage system and stream sediments from local streams were investigated for the first time in the urban area of Idrija town, the central part of the second largest and strongly contaminated Hg mining district in the world. Hg concentrations in road sediments were lower than in stream sediments. They ranged from 16 to 110 mg/kg (Md = 29 mg/kg) for <0.125 mm particles and from 7 to 125 mg/kg (Md = 35 mg/kg) for <0.04 mm particles, while Hg concentrations in stream sediments ranged from 10 to 610 mg/kg (Md = 95 mg/kg) for <0.125 particles and from 10 to 440 mg/kg (Md = 105 mg/kg) for <0.04 mm particles. High Hg loadings in stream sediments were successfully linked with identified mercury sources (rocks containing mercury ore, areas of former ore roasting sites, ore residue dumps), because they are located in the drainage areas of streams, from which the sediments were collected. Links between Hg loadings in road sediments and identified mercury sources were not recognized. Solid phases of Hg were determined by thermo-desorption technique and are similar for both types of sediments. Results show the occurrence of three different forms: elemental mercury, mercury bound to matrix components and cinnabar. Approximately 50 % of Hg in samples consist of non-cinnabar fractions. This is important, since they are potentially bioavailable. An interesting new discovery according to previous research of environmental media from Idrija area by solid-phase Hg thermo-desorption technique is that elemental mercury was determined in almost all investigated sediments in minor amounts (Md = 3 %).
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Affiliation(s)
- Spela Bavec
- Geological Survey of Slovenia, Dimičeva ulica 14, 1000, Ljubljana, Slovenia,
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