1
|
Cui Z, Shi X, Zhao S, Lu J, Tian Z, Zhang H, Guo X, Wang Y. Distributions of total mercury and methylmercury and regulating factors in lake water and surface sediment in the cold-arid Wuliangsuhai Lake region. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:7999-8013. [PMID: 37523029 DOI: 10.1007/s10653-023-01690-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 07/11/2023] [Indexed: 08/01/2023]
Abstract
This study aimed to understand the occurrence of mercury in the water environment of typical cold and arid lakes and the regulating environmental factors. Water and surface sediment samples were collected from July to August, 2022 in the Wuliangsuhai Lake region for the analysis of total mercury (THg) and total methylmercury (TMeHg). Lake water THg and TMeHg ranged between 19.20 ~ 668.10 and 0.10 ~ 11.40 ng/L, respectively, exceeding China's environmental quality standards and contents of other lakes and reservoirs in China and other areas. Surface sediments showed lower mean THg and TMeHg of 261.85 and 0.18 μg/kg, respectively, with the former significantly exceeding the background value of Inner Mongolia and unpolluted natural lakes but lower than those of lakes affected by human factors, such as aquaculture. Sediments showed relatively low methylation and TMeHg (0.01-0.21%) concentrations. Correlation analysis identified salinity, total dissolved solids, conductivity, and redox potential as important factors affecting mercury speciation in water, whereas those in surface sediments were organic matter, pH, and total iron content. This study conducted preliminary research on the different species of Hg in Wuliangsuhai Lake water environment, which can provide scientific evidence for the specific treatment of Hg pollution in agriculture, or industry and other related fields. Our results suggest that upstream and downstream regulatory agencies should strengthen the regulation of agricultural and industrial production, moderately reduce human activities, and reduce the use of mercury-rich substances such as pesticides.
Collapse
Affiliation(s)
- Zhimou Cui
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
| | - Xiaohong Shi
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China.
- Water Resources Protection and Utilization Key Laboratory, Inner Mongolia Agricultural University, Hohhot, 010018, China.
| | - Shengnan Zhao
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
- Water Resources Protection and Utilization Key Laboratory, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Junping Lu
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
- Water Resources Protection and Utilization Key Laboratory, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Zhiqiang Tian
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
| | - Hao Zhang
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
| | - Xin Guo
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
| | - Yanjun Wang
- Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot, China
| |
Collapse
|
2
|
Zhou J, Bollen SW, Roy EM, Hollinger DY, Wang T, Lee JT, Obrist D. Comparing ecosystem gaseous elemental mercury fluxes over a deciduous and coniferous forest. Nat Commun 2023; 14:2722. [PMID: 37169778 PMCID: PMC10175444 DOI: 10.1038/s41467-023-38225-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/21/2023] [Indexed: 05/13/2023] Open
Abstract
Sources of neurotoxic mercury in forests are dominated by atmospheric gaseous elemental mercury (GEM) deposition, but a dearth of direct GEM exchange measurements causes major uncertainties about processes that determine GEM sinks. Here we present three years of forest-level GEM deposition measurements in a coniferous forest and a deciduous forest in northeastern USA, along with flux partitioning into canopy and forest floor contributions. Annual GEM deposition is 13.4 ± 0.80 μg m-2 (coniferous forest) and 25.1 ± 2.4 μg m-2 (deciduous forest) dominating mercury inputs (62 and 76% of total deposition). GEM uptake dominates in daytime during active vegetation periods and correlates with CO2 assimilation, attributable to plant stomatal uptake of mercury. Non-stomatal GEM deposition occurs in the coniferous canopy during nights and to the forest floor in the deciduous forest and accounts for 24 and 39% of GEM deposition, respectively. Our study shows that GEM deposition includes various pathways and is highly ecosystem-specific, which complicates global constraints of terrestrial GEM sinks.
Collapse
Affiliation(s)
- Jun Zhou
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Silas W Bollen
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
| | - Eric M Roy
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Ting Wang
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA
| | - John T Lee
- School of Forest Resources, University of Maine, Orono, ME, USA
| | - Daniel Obrist
- Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts, Lowell, MA, USA.
- University of California, Agriculture and Natural Resources, Davis, CA, USA.
| |
Collapse
|
3
|
Ulus Y, Tsui MTK, Sakar A, Nyarko P, Aitmbarek NB, Ardón M, Chow AT. Declines of methylmercury along a salinity gradient in a low-lying coastal wetland ecosystem at South Carolina, USA. CHEMOSPHERE 2022; 308:136310. [PMID: 36088973 DOI: 10.1016/j.chemosphere.2022.136310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
Wetlands are widely regarded as biogeochemical hotspots of highly toxic methylmercury (MeHg), mainly mediated by sulfate-reducing bacteria. In low-lying coastal wetlands, sea level rise, a phenomenon caused by global climate change, is slowly degrading numerous healthy freshwater forested wetlands into salt-degraded counterparts with a nickname "ghost forests", and eventually converting them to saltmarshes. However, little is known about the changes of mercury (Hg) methylation, bioaccumulation, and biomagnification along the forest-to-saltmarsh gradient. Here, we conducted extensive field sampling in three wetland states (healthy forested wetlands, salt-degraded forested wetlands, and saltmarsh) along a salinity gradient (from 0 to 9.4 ppt) in Winyah Bay, South Carolina, USA. We found that in our study wetland systems the saltmarshes had the lowest levels of both total Hg and MeHg in sediments and biota, as compared to healthy forested wetlands and saltwater-degraded ghost forests. Our results suggest that the slow conversion of forested wetland to saltmarsh could reduce net MeHg production in our study wetland systems, which we hypothesized that could be attributed to increased sulfate reduction and excessive buildup of sulfide in sediment that inhibits microbial Hg methylation, and/or reduced canopy density and increased photodegradation of MeHg. However, it should be noted that biogeochemical MeHg responses to salinity changes may be site-specific and we urge more similar studies in other wetland systems along a salinity gradient. Therefore, long-term salinization of coastal wetlands and the slow conversion of forests to marshes could decrease long-term exposure of toxic MeHg levels in coastal food webs that are similar to our system, and ultimately reduce human exposure to this neurotoxin.
Collapse
Affiliation(s)
- Yener Ulus
- Department of Environmental Studies, Davidson College, Davidson, NC, 28035, USA; Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA; School of Life Sciences, Earth and Environmental Sciences Programme, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
| | - Aslihan Sakar
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Paul Nyarko
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Nadia B Aitmbarek
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Marcelo Ardón
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA
| | - Alex T Chow
- Biogeochemistry and Environmental Quality Research Group, Clemson University, Georgetown, SC, 29442, USA
| |
Collapse
|