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Chen L, Cheng G, Zhou Z, Liang Y, Ci Z, Yin Y, Liu G, Cai Y, Li Y. Methylmercury cycling in the Bohai Sea and Yellow Sea: Reasons for the low system efficiency of methylmercury production. WATER RESEARCH 2024; 258:121792. [PMID: 38772318 DOI: 10.1016/j.watres.2024.121792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 05/08/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024]
Abstract
Coastal seas contribute the majority of human methylmercury (MeHg) exposure via marine fisheries. The terrestrial area surrounding the Bohai Sea and Yellow Sea (BS and YS) is one of the mercury (Hg) emission "hot spots" in the world, resulting in high concentrations of Hg in BS and YS seawater in comparison to other marine systems. However, comparable or even lower Hg levels were detected in seafood from the BS and YS than other coastal regions around the word, suggesting a low system bioaccumulation of Hg. Reasoning a low system efficiency of MeHg production (represented by MeHg/THg (total Hg) in seawater) may be present in these two systems, seven cruises were conducted in the BS and YS to test this hypothesis. MeHg/THg ratios in BS and YS seawater were found to be lower than that in most coastal systems, indicating that the system efficiency of MeHg production is relatively lower in the BS and YS. The low system efficiency of MeHg production reduces the risk of Hg in the BS and YS with high Hg discharge intensity. By measuring in situ production and degradation of MeHg using double stable isotope addition method, and MeHg discharge flux from various sources and its exchange at various interfaces, the budgets of MeHg in the BS and YS were estimated. The results indicate that in situ methylation and demethylation are the major source and sink of MeHg in the BS and YS. By comparing the potential controlling processes and environmental parameters for MeHg/THg in the BS and YS with the other coastal seas, estuaries and bays, lower transport efficiency of inorganic Hg from water column to the sediment, slower methylation of Hg, and rapid demethylation of MeHg were identified to be major reasons for the low system efficiency of MeHg production in the BS and YS. This study highlights the necessity of monitoring the system efficiency of MeHg production, associated processes, and controlling parameters to evaluate the efficiency of reducing Hg emissions in China as well as the other countries.
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Affiliation(s)
- Lufeng Chen
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, PR China
| | - Guoyi Cheng
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, PR China
| | - Zhengwen Zhou
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, PR China
| | - Yong Liang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, PR China
| | - Zhijia Ci
- School of Marine Sciences, Sun Yat-Sen University, Guangzhou, 519082, PR China
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect and State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
| | - Yong Cai
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
| | - Yanbin Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, PR China.
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Narvaez-Montoya C, Mahlknecht J, Torres-Martínez JA, Mora A, Pino-Vargas E. FlowSOM clustering - A novel pattern recognition approach for water research: Application to a hyper-arid coastal aquifer system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:169988. [PMID: 38211857 DOI: 10.1016/j.scitotenv.2024.169988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/13/2024]
Abstract
Monitoring and understanding of water resources have become essential in designing effective and sustainable management strategies to overcome the growing water quality challenges. In this context, the utilization of unsupervised learning techniques for evaluating environmental tracers has facilitated the exploration of sources and dynamics of groundwater systems through pattern recognition. However, conventional techniques may overlook spatial and temporal non-linearities present in water research data. This paper introduces the adaptation of FlowSOM, a pioneering approach that combines self-organizing maps (SOM) and minimal spanning trees (MST), with the fast-greedy network clustering algorithm to unravel intricate relationships within multivariate water quality datasets. By capturing connections within the data, this ensemble tool enhances clustering and pattern recognition. Applied to the complex water quality context of the hyper-arid transboundary Caplina/Concordia coastal aquifer system (Peru/Chile), the FlowSOM network and clustering yielded compelling results in pattern recognition of the aquifer salinization. Analyzing 143 groundwater samples across eight variables, including major ions, the approach supports the identification of distinct clusters and connections between them. Three primary sources of salinization were identified: river percolation, slow lateral aquitard recharge, and seawater intrusion. The analysis demonstrated the superiority of FlowSOM clustering over traditional techniques in the case study, producing clusters that align more closely with the actual hydrogeochemical pattern. The outcomes broaden the utilization of multivariate analysis in water research, presenting a comprehensive approach to support the understanding of groundwater systems.
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Affiliation(s)
- Christian Narvaez-Montoya
- Escuela de Ingenieria y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico
| | - Jürgen Mahlknecht
- Escuela de Ingenieria y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico.
| | - Juan Antonio Torres-Martínez
- Escuela de Ingenieria y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico
| | - Abrahan Mora
- Escuela de Ingenieria y Ciencias, Tecnologico de Monterrey, Ave. Eugenio Garza Sada 2501, Monterrey, N.L. 64849, Mexico
| | - Edwin Pino-Vargas
- Facultad de Ingenieria Civil, Arquitectura y Geotecnia, Universidad Nacional Jorge Basadre Grohmann, Av. Miraflores S/N, Tacna 23000, Peru
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Nelson SJ, Willacker J, Eagles-Smith C, Flanagan Pritz C, Chen CY, Klemmer A, Krabbenhoft DP. Habitat and dissolved organic carbon modulate variation in the biogeochemical drivers of mercury bioaccumulation in dragonfly larvae at the national scale. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169396. [PMID: 38114036 DOI: 10.1016/j.scitotenv.2023.169396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/21/2023]
Abstract
We paired mercury (Hg) concentrations in dragonfly larvae with water chemistry in 29 U.S. national parks to highlight how ecological and biogeochemical context (habitat, dissolved organic carbon [DOC]) influence drivers of Hg bioaccumulation. Although prior studies have defined influences of biogeochemical variables on Hg production and bioaccumulation, it has been challenging to determine their influence across diverse habitats, regions, or biogeochemical conditions within a single study. We compared global (i.e., all sites), habitat-specific, and DOC-class models to illuminate how these controls on biotic Hg vary. Although the suite of important biogeochemical factors across all sites (e.g., aqueous Hg, DOC, sulfate [SO42-], and pH) was consistent with general findings in the literature, contrasting the restricted models revealed more nuanced controls on biosentinel Hg. Comparing habitats, aqueous (filtered) total mercury (THg) and SO42- were important in lentic systems whereas aqueous (filtered) methylmercury (MeHg), DOC, pH, and SO42- were important in lotic and wetland systems. The ability to identify important variables varied among habitats, with less certainty in lentic (model weight (W) = 0.05) than lotic (W = 0.11) or wetland habitats (W = 0.23), suggesting that biogeochemical drivers of bioaccumulation are more variable, or obscured by other aspects of Hg cycling, in these habitats. Results revealed a contrast in the importance of aqueous MeHg versus aqueous THg between DOC-classes: in low-DOC sites (<8.5 mg/L), availability of upstream inputs of MeHg appeared more important for bioaccumulation; in high-DOC sites (>8.5 mg/L) THg was more important, suggesting a link to in-situ controls on bioavailability of Hg for MeHg production. Mercury bioaccumulation (indicated by bioaccumulation factor) was more efficient in low DOC-class sites, likely due to reduced partitioning of aqueous MeHg to DOC. Together, findings highlight substantial variation in the drivers of Hg bioaccumulation and suggest consideration of these factors in natural resource management and decision-making.
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Affiliation(s)
- Sarah J Nelson
- Appalachian Mountain Club, Gorham, NH 03581, USA; University of Maine, School of Forest Resources, Orono, ME 04469, USA.
| | - James Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97330, USA
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97330, USA
| | - Colleen Flanagan Pritz
- National Park Service, Air Resources Division, Natural Resource, Stewardship and Science Directorate, Lakewood, CO 80228, USA
| | | | - Amanda Klemmer
- School of Biology and Ecology, University of Maine, 5722 Deering Hall, Orono, ME 04469, USA
| | - David P Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, 1 Gifford Pinchot Dr., Madison, WI 53726, USA
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Liu M, Mason RP, Vlahos P, Whitney MM, Zhang Q, Warren JK, Wang X, Baumann Z. Riverine Discharge Fuels the Production of Methylmercury in a Large Temperate Estuary. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13056-13066. [PMID: 37603456 DOI: 10.1021/acs.est.3c00473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Estuaries are an important food source for the world's growing population, yet human health is at risk from elevated exposure to methylmercury (MeHg) via the consumption of estuarine fish. Moreover, the sources and cycling of MeHg in temperate estuarine ecosystems are poorly understood. Here, we investigated the seasonal and tidal patterns of mercury (Hg) forms in Long Island Sound (LIS), in a location where North Atlantic Ocean waters mix with the Connecticut River. We found that seasonal variations in Hg and MeHg in LIS followed the extent of riverine Hg delivery, while tides further exacerbated the remobilization of earlier deposited riverine Hg. The net production of MeHg near the river plume was significant compared to that in other locations and enhanced during high tide, possibly resulting from the enhanced microbial activity and organic carbon remineralization in the river plume. Statistical models, driven by our novel data, further support the hypothesis that the river-delivered organic matter and inorganic Hg drive net MeHg production in the estuarine water column. Our study sheds light on the significance of water column biogeochemical processes in temperate tidal estuaries in regulating MeHg levels and inspires new questions in our quest to understand MeHg sources and dynamics in coastal oceans.
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Affiliation(s)
- Maodian Liu
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Science, Peking University, Beijing 100871, China
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
- School of the Environment, Yale University, New Haven, Connecticut 06511, United States
| | - Robert P Mason
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
| | - Penny Vlahos
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
| | - Michael M Whitney
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
| | - Qianru Zhang
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Science, Peking University, Beijing 100871, China
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Joseph K Warren
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
| | - Xuejun Wang
- Ministry of Education Laboratory of Earth Surface Process, College of Urban and Environmental Science, Peking University, Beijing 100871, China
| | - Zofia Baumann
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
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Sonke JE, Angot H, Zhang Y, Poulain A, Björn E, Schartup A. Global change effects on biogeochemical mercury cycling. AMBIO 2023; 52:853-876. [PMID: 36988895 PMCID: PMC10073400 DOI: 10.1007/s13280-023-01855-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/07/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
Past and present anthropogenic mercury (Hg) release to ecosystems causes neurotoxicity and cardiovascular disease in humans with an estimated economic cost of $117 billion USD annually. Humans are primarily exposed to Hg via the consumption of contaminated freshwater and marine fish. The UNEP Minamata Convention on Hg aims to curb Hg release to the environment and is accompanied by global Hg monitoring efforts to track its success. The biogeochemical Hg cycle is a complex cascade of release, dispersal, transformation and bio-uptake processes that link Hg sources to Hg exposure. Global change interacts with the Hg cycle by impacting the physical, biogeochemical and ecological factors that control these processes. In this review we examine how global change such as biome shifts, deforestation, permafrost thaw or ocean stratification will alter Hg cycling and exposure. Based on past declines in Hg release and environmental levels, we expect that future policy impacts should be distinguishable from global change effects at the regional and global scales.
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Affiliation(s)
- Jeroen E. Sonke
- Géosciences Environnement Toulouse, CNRS/IRD, Université Paul Sabatier Toulouse 3, 14 ave Edouard Belin, 31400 Toulouse, France
| | - Hélène Angot
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, 1025 rue de la piscine, 38000 Grenoble, France
| | - Yanxu Zhang
- School of Atmospheric Sciences, Nanjing University, 163 Xianlin Road, Nanjing, 210023 Jiangsu China
| | - Alexandre Poulain
- Department of Biology, University of Ottawa, Ottawa, ON K1N6N5 Canada
| | - Erik Björn
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden
| | - Amina Schartup
- Geosciences Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
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Willacker JJ, Eagles-Smith CA, Nelson SJ, Flanagan Pritz CM, Krabbenhoft DP. The influence of short-term temporal variability on the efficacy of dragonfly larvae as mercury biosentinels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 867:161469. [PMID: 36632899 DOI: 10.1016/j.scitotenv.2023.161469] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
Mercury (Hg) exposure to fish, wildlife, and humans is widespread and of global concern, thus stimulating efforts to reduce emissions. Because the relationships between rates of inorganic Hg loading, methylmercury (MeHg) production, and bioaccumulation are extremely complex and challenging to predict, there is a need for reliable biosentinels to understand the distribution of Hg in the environment and monitor the effectiveness of reduction efforts. However, it is important to assess how temporal and spatial variation at multiple scales influences the efficacy of specific biosentinels. Seasonal and interannual variation in total Hg (THg) concentrations of dragonfly larvae were examined in relation to spatial variability among 21 sites in two U.S. national parks with contrasting ecologies and Hg deposition patterns. Dragonfly THg differed among sampling events at 17 of the 21 sites, but by an average of only 20.4 % across events, compared to an average difference of 52.7 % among sites. Further, THg concentrations did not follow consistent seasonal patterns across sites or years, suggesting that the observed temporal variation was unlikely to bias monitoring efforts. Importantly, for a specific site, there was no difference in % MeHg in dragonflies among sampling events. Finally, there was significant temporal variability in the biogeochemical factors (aqueous inorganic Hg, aqueous MeHg, DOC, SO4, and pH) influencing dragonfly THg, with the importance of individual factors varying by 2.4 to 4.3-fold across sampling events. Despite these results, it is noteworthy that the observed temporal variation in dragonfly THg concentrations was neither large nor consistent enough to bias spatial assessments. Thus, although this temporal variation may provide insights into the processes influencing biological Hg concentrations, it is unlikely to impair the use of dragonflies as biosentinels for monitoring spatial or temporal patterns at scales relevant to most mitigation efforts.
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Affiliation(s)
- James J Willacker
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - Sarah J Nelson
- Appalachian Mountain Club, 361 Route 16, Gorham, NH 03581, USA
| | | | - David P Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, 1 Gifford Pinchot Dr, Madison, WI 53726, USA
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Pérez-Iglesias JM, Bach NC, Colombetti PL, Acuña P, Colman-Lerner JE, González SP, Brodeur JC, Almeida CA. Biomonitoring of Alterations in Fish That Inhabit Anthropic Aquatic Environments in a Basin from Semi-Arid Regions. TOXICS 2023; 11:73. [PMID: 36668799 PMCID: PMC9863756 DOI: 10.3390/toxics11010073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Industrial, agricultural, and urban areas can be sources of pollution and a cause of habitat fragmentation. The Conlara River located in the northeast of San Luis Province suffers different environmental pressures along its course from urban to agro-industrial areas. The present study aims to assess the water quality of the Conlara basin by evaluating how metals and pesticide contamination as well as physicochemical parameters relate to physiological stress in Jenynsia multidentata. Samplings were carried out in four sites characterized by a growing gradient of anthropic impact from the springs to the final sections of the river, starting with tourism passing through urban areas and ending with large agricultural areas (from S1 to S4) during both the dry and wet seasons. A total of 27 parameters were determined (11 physicochemical, 9 heavy metals, and 7 pesticides) in surface waters. Biomarkers (CAT, TBARS, ChE, and MN) showed significant physiological and cytological alterations in J. multidentata depending on the hydrology season. The combination of physicochemical parameters, metals, and pesticide levels allowed typification and differentiation of the sites. Some metal (Cr, Mn, Pb, and Zn) and pesticide (α-BHC, chlorpyrifos, permethrin and cypermethrin, and endosulfan α) levels recorded exceeded the recommended Argentinian legislation values. A principal component analysis (PCA) allowed detection of differences between both seasons and across sites. Furthermore, the differences in distances showed by PCA between the sites were due to differences in the presence of physicochemical parameters, metals, and pesticides correlated with several biomarkers' responses depending on type of environmental stressor. Water quality evaluation along the Conlara River shows deterioration and different types of environmental stressors, identifying zones, and specific sources of pollution. Furthermore, the biomarkers suggest that the native species could be sensitive to anthropogenic environmental pressures.
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Affiliation(s)
- Juan Manuel Pérez-Iglesias
- Laboratorio de Química Analítica Ambiental (LAQUAA), Instituto de Química de San Luis (INQUISAL-CONICET), FQByF, UNSL, Ejército de Los Andes 950, San Luis D5700, Argentina
- Departamento de Ciencias Ambientales y Producción, Universidad Nacional de Los Comechingones, Héroes de Malvinas S/N, Merlo, San Luis D5881, Argentina
| | - Nadia Carla Bach
- Área de Biología, Facultad de Química, Bioquímica y Farmacia (FQByF), Universidad Nacional de San Luis (UNSL), Ejército de Los Andes 950, San Luis D5700, Argentina
| | - Patricia Laura Colombetti
- Laboratorio de Química Analítica Ambiental (LAQUAA), Instituto de Química de San Luis (INQUISAL-CONICET), FQByF, UNSL, Ejército de Los Andes 950, San Luis D5700, Argentina
- Departamento de Ciencias Ambientales y Producción, Universidad Nacional de Los Comechingones, Héroes de Malvinas S/N, Merlo, San Luis D5881, Argentina
- Área de Biología, Facultad de Química, Bioquímica y Farmacia (FQByF), Universidad Nacional de San Luis (UNSL), Ejército de Los Andes 950, San Luis D5700, Argentina
| | - Pablo Acuña
- Laboratorio de Química Analítica Ambiental (LAQUAA), Instituto de Química de San Luis (INQUISAL-CONICET), FQByF, UNSL, Ejército de Los Andes 950, San Luis D5700, Argentina
| | - Jorge Esteban Colman-Lerner
- Centro de Investigación y Desarrollo en Ciencias Aplicadas “Dr. Jorge J. Ronco” (CINDECA), La Plata B1900, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, (CONICET), La Plata B1900, Argentina
| | - Silvia Patricia González
- Laboratorio de Química Analítica Ambiental (LAQUAA), Instituto de Química de San Luis (INQUISAL-CONICET), FQByF, UNSL, Ejército de Los Andes 950, San Luis D5700, Argentina
| | - Julie Celine Brodeur
- Instituto de Recursos Biológicos, Centro de Investigaciones de Recursos Naturales (CIRN), Hurlingham B1686, Argentina
- Instituto Nacional de Tecnología Agropecuaria (INTA), Hurlingham B1686, Argentina
| | - Cesar Américo Almeida
- Laboratorio de Química Analítica Ambiental (LAQUAA), Instituto de Química de San Luis (INQUISAL-CONICET), FQByF, UNSL, Ejército de Los Andes 950, San Luis D5700, Argentina
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8
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Mason RP, Coulibaly M, Hansen G, Inman H, Myer PK, Yao KM. An examination of mercury levels in the coastal environment and fish of Cote d'Ivoire. CHEMOSPHERE 2022; 300:134609. [PMID: 35430197 DOI: 10.1016/j.chemosphere.2022.134609] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/04/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Artisanal and small-scale gold mining (ASGM), energy production and other industrial inputs are a major source of anthropogenic mercury (Hg) to the aquatic environment globally, and these inputs have led to environmental contamination and human exposure. While studies have documented the effects of Hg inputs to rivers and marine waters of the West African region, estuarine waters of Cote d'Ivoire have been understudied, besides the waters surrounding Abidjan. To fill this gap, and to examine the potential for human exposure to methylmercury (MeHg), we measured the concentrations of total Hg, MeHg, and ancillary parameters in water (dissolved and particulate phases), sediment and fish to determine the extent of environmental impact and the potential for MeHg exposure for people consuming these fish. Levels of Hg and MeHg in sediment were elevated in the vicinity of the urban environment (up to 0.3 ng/g dry weight (dw) MeHg and 623 ng/g dw total Hg) and lowest in the more remote estuarine environments. Measurements of Hg in tuna and other larger pelagic coastal species indicated that levels were elevated but comparable to other North Atlantic regions. However, levels of Hg in fish, even smaller estuarine species, were such that the rural and urban populations are potentially being exposed to unsafe levels of MeHg, primarily as a result of the relatively high fish consumption in Cote d'Ivoire compared to other countries. Overall, both local point sources and the transport of Hg used in interior ASGM activities are the sources for Hg contamination to these coastal waters.
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Affiliation(s)
- R P Mason
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA.
| | - M Coulibaly
- Ecole Normale Superieure (ENS), Abidjan, Cote d'Ivoire
| | - G Hansen
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| | - H Inman
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| | - P K Myer
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| | - K M Yao
- Oceanographic Institute, Abidjan, Cote d'Ivoire
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9
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Li X, Wang Q, Xing M, Ma Z, Li Y, Zhou X. Typical scaled food web structure and total mercury enrichment characteristics in Xingkai Lake, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:58297-58311. [PMID: 35366206 DOI: 10.1007/s11356-022-19874-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
Different from the widely used constant discrimination factor Δ15N = 3.4‰ between two adjacent trophic positions (TPs), a scaled Δ15N framework for evaluating the TP of species was developed in 2014, that is, the Δ15N between two adjacent TPs decreases as the TP increases which is considered to be in closer conformity to the trophic cascade in the natural food web. In this study, we compared the two TP calculation methods and then reconsidered the evaluation of the trophic magnification factors (TMFs). Our results show that the TPscaled value is higher and the TMFs value is lower under the scaled Δ15N framework, indicating that the TMFs value under the constant Δ15N framework is often overestimated. We further constructed a diet proportion food web model, which shows that species with lower TP has higher contribution rate as food sources. In Xingkai Lake, the enrichment process of mercury in the food web is not strictly consistent with the diet proportion of the food web. Based on the diet proportion food web model and the mercury enrichment model, it can be found that the White shrimp (Exopalaemon modestus) is not only an important food source, but also the main source of mercury transmission in the food web. Overall, our findings have quantified the food web construction and thus facilitated a better understanding of the interaction between the diet proportion and the bio-concentration in the food web.
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Affiliation(s)
- Xingchun Li
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, 150040, Heilongjiang Province, China
| | - Qiang Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, Jilin Province, China
| | - Minyan Xing
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, 150040, Heilongjiang Province, China
| | - Zhilong Ma
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, 150040, Heilongjiang Province, China
| | - Yike Li
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, 150040, Heilongjiang Province, China
| | - Xuehong Zhou
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, 150040, Heilongjiang Province, China.
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10
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He X, Wallace WG, Reinfelder JR. Grass Shrimp ( Palaemonetes pugio) as a Trophic Link for Methylmercury Accumulation in Urban Salt Marshes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8071-8081. [PMID: 35584355 DOI: 10.1021/acs.est.2c01184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Grass shrimp (Palaemonetes pugio) represent a potential link in the transfer of methylmercury (MeHg) from salt marsh sediments to transient young-of-the-year (YOY) fish. Across six salt marshes subject to varying degrees of Hg contamination, MeHg concentration in grass shrimp was significantly correlated with MeHg in sediment (p < 0.05, R2 = 0.81). Bioenergetic models show that grass shrimp alone account for 12-90% of MeHg observed in YOY striped bass and 6-22% of MeHg in YOY summer flounder. Direct accumulation of MeHg from grass shrimp to YOY fish increased with MeHg levels in grass shrimp and sediment. However, in the most contaminated salt marshes with the highest levels of MeHg in grass shrimp and sediment, indirect accumulation of MeHg from grass shrimp by YOY summer flounder, whose diet is dominated by benthic forage fish (mummichog), is predicted to plateau because higher concentrations of MeHg in grass shrimp are offset by a lower proportion of grass shrimp in the mummichog diet. Our results demonstrate that grass shrimp are an important trophic link in the bioaccumulation of MeHg in salt marsh food webs and that MeHg accumulation in YOY fish varies with both the concentration of MeHg in salt marsh sediments and benthic food web structure.
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Affiliation(s)
- Xiaoshuai He
- Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey 08901, United States
| | - William G Wallace
- Department of Biology, College of Staten Island, City University of New York, Staten Island, New York 10314, United States
| | - John R Reinfelder
- Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey 08901, United States
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Davis DA, Garamszegi SP, Banack SA, Dooley PD, Coyne TM, McLean DW, Rotstein DS, Mash DC, Cox PA. BMAA, Methylmercury, and Mechanisms of Neurodegeneration in Dolphins: A Natural Model of Toxin Exposure. Toxins (Basel) 2021; 13:toxins13100697. [PMID: 34678990 PMCID: PMC8540894 DOI: 10.3390/toxins13100697] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 01/15/2023] Open
Abstract
Dolphins are well-regarded sentinels for toxin exposure and can bioaccumulate a cyanotoxin called β-N-methylamino-l-alanine (BMAA) that has been linked to human neurodegenerative disease. The same dolphins also possessed hallmarks of Alzheimer’s disease (AD), suggesting a possible association between toxin exposure and neuropathology. However, the mechanisms of neurodegeneration in dolphins and the impact cyanotoxins have on these processes are unknown. Here, we evaluate BMAA exposure by investigating transcription signatures using PCR for dolphin genes homologous to those implicated in AD and related dementias: APP, PSEN1, PSEN2, MAPT, GRN, TARDBP, and C9orf72. Immunohistochemistry and Sevier Münger silver staining were used to validate neuropathology. Methylmercury (MeHg), a synergistic neurotoxicant with BMAA, was also measured using PT-GC-AFS. We report that dolphins have up to a three-fold increase in gene transcription related to Aβ+ plaques, neurofibrillary tangles, neuritic plaques, and TDP-43+ intracytoplasmic inclusions. The upregulation of gene transcription in our dolphin cohort paralleled increasing BMAA concentration. In addition, dolphins with BMAA exposures equivalent to those reported in AD patients displayed up to a 14-fold increase in AD-type neuropathology. MeHg was detected (0.16–0.41 μg/g) and toxicity associated with exposure was also observed in the brain. These results demonstrate that dolphins develop neuropathology associated with AD and exposure to BMAA and MeHg may augment these processes.
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Affiliation(s)
- David A. Davis
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
- Correspondence:
| | - Susanna P. Garamszegi
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
| | - Patrick D. Dooley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
| | - Thomas M. Coyne
- Office of the District 21 Medical Examiner, Fort Myers, FL 33907, USA;
| | - Dylan W. McLean
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
| | | | - Deborah C. Mash
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (S.P.G.); (P.D.D.); (D.W.M.); (D.C.M.)
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Dr. Kiran C. Patel College of Allopathic Medicine, Nova Southeastern University, Davie, FL 33328, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA; (S.A.B.); (P.A.C.)
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Zhang Z, Chen L, Cheng M, Liu M, Wang X. Biotransport of mercury and human methylmercury exposure through crabs in China - A life cycle-based analysis. JOURNAL OF HAZARDOUS MATERIALS 2021; 415:125684. [PMID: 33765564 DOI: 10.1016/j.jhazmat.2021.125684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/28/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Exposure to methylmercury (MeHg) has various toxic effects on humans. The evaluation of human MeHg exposure has previously focused on fish consumption. However, in this study, we found that MeHg levels in domestic crabs in China were also relatively high (range: 50-1400 ng/g, dry weight). The high MeHg levels in crabs and their high consumption do not match the risk assessment of MeHg, indicating an underestimated exposure risk, especially in MeHg-sensitive groups such as pregnant women. The annual crab MeHg content output in China was estimated to be 30 ± 27 kg. A total of 6.8% of the country's land area contributes 71% of the MeHg output. However, 66% of the output is redistributed to non-crab-producing regions via interregional food trade, posing risks to the population on a national scale. The daily intake of MeHg from crabs could easily exceed the reference dose (0.1 µg/kg of body weight per day) suggested by the United States Environmental Protection Agency with consideration of coexposure from fish, rice, and other food sources. We suggest that future MeHg exposure analysis includes crab MeHg as a coexposure pathway to estimate the dietary MeHg limit accurately and emphasize the influence of interregional food trade on MeHg exposure.
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Affiliation(s)
- Zhihao Zhang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Long Chen
- Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, Shanghai 200241, China
| | - Menghan Cheng
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Maodian Liu
- School of the Environment, Yale University, New Haven, Connecticut 06511, USA.
| | - Xuejun Wang
- Ministry of Education Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
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