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Henriques MC, Carvalho I, Santos C, Herdeiro MT, Fardilha M, Pavlaki MD, Loureiro S. Unveiling the molecular mechanisms and developmental consequences of mercury (Hg) toxicity in zebrafish embryo-larvae: A comprehensive approach. Neurotoxicol Teratol 2023; 100:107302. [PMID: 37739188 DOI: 10.1016/j.ntt.2023.107302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 09/24/2023]
Abstract
Mercury (Hg) is a global contaminant affecting aquatic ecosystems' health. Chronic exposure to Hg has shown that the normal development of zebrafish embryo-larvae is affected. However, the molecular mechanisms behind the toxicity of Hg on fish embryonic development are still poorly understood. This work aimed to investigate the effects of Hg exposure on zebrafish embryo-larvae using a combined approach at individual (mortality, embryo development and locomotor behavior) and biochemical (neurotoxicity and oxidative stress enzymatic activities and protein phosphatase expression) levels. The Fish Embryo Toxicity assay followed the Organization for Economic Cooperation and Development Guideline 236 and used a concentration range between 13 and 401 μg Hg/L. Lethal and developmental endpoints were examined at 24, 48, 72 and 96 hpf. Biochemical markers, including Acetylcholinesterase (AChE), Catalase (CAT), Glutathione Reductase (GR), and Glutathione-S-Transferase (GST) activities and, for the first time, the expression of the protein phosphatase 1 gamma (PP1γ) was assessed after 24, 48, 72 and 96 h of exposure to 10 and 100 μg Hg/L. The behavioral effects of a sublethal range of Hg (from 0.8 to 13 μg Hg/L) were assessed using an automated video tracking system at 120 hpf. Several developmental abnormalities on zebrafish embryos and larvae, including pericardial edema, spin and tail deformities and reduced rate of consumption of the yolk sac, were found after exposure to Hg (LC50 at 96 hpf of 139 μg Hg/L) with EC50 values for total malformations ranging from 22 to 264 μg Hg/L. After 96 hpf, no significant effects were observed in the CAT and GR activities. However, an increase in the GST activity in a concentration and time-dependent manner was found, denoting possible stress-related adaptation of zebrafish embryos to deleterious effects of Hg exposure. The AchE activity showed a response pattern in line with the behavioral responses. At the lowest concentration tested, no significant effects were found for the AChE activity, whereas a decrease in AChE activity was observed at 100 μg Hg/L, suggesting that exposure to Hg induced neurotoxic effects in zebrafish embryos which in turn may explain the lack of equilibrium found in this study (EC50 at 96 hpf of 83 μg Hg/L). Moreover, a decrease in the PP1γ expression was found after 96 h of exposure to 10 and 100 μg Hg/L. Thus, we suggest that Hg may be an inhibitor of PP1γ in zebrafish embryos-larvae and thus, along with the alterations in the enzymatic activity of GST, explain some of the developmental malformations observed, as well as the lack of equilibrium. Hence, in this study, we propose the use of PP1 expression, in combination with apical and biochemical endpoints, as a precursor for assessing Hg's toxic mechanism on embryonic development.
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Affiliation(s)
- Magda Carvalho Henriques
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal; CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Inês Carvalho
- Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Cátia Santos
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Maria Teresa Herdeiro
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Margarida Fardilha
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Maria Dimitriou Pavlaki
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal.
| | - Susana Loureiro
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
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Blazer VS, Walsh HL, Sperry AJ, Raines B, Willacker JJ, Eagles-Smith CA. A multi-level assessment of biological effects associated with mercury concentrations in smallmouth bass, Micropterus dolomieu. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 329:121688. [PMID: 37088253 DOI: 10.1016/j.envpol.2023.121688] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/11/2023] [Accepted: 04/20/2023] [Indexed: 05/03/2023]
Abstract
Total mercury (THg) was measured in muscle (fillet) and liver tissue of adult smallmouth bass Micropterus dolomieu collected at multiple sites in the Potomac and Susquehanna River drainages within the Chesapeake Bay watershed. Smallmouth bass in these drainages have experienced episodic mortality events, a high prevalence of skin lesions and reproductive endocrine disruption (intersex or testicular oocytes and plasma vitellogenin in males). A multi-level assessment of general and reproductive health including indicators at the organismal, organ, cellular and molecular levels was conducted on adult smallmouth bass during the spring (prespawn) season. Concentrations of THg were correlated with increased visible abnormalities, increased macrophage aggregates and tissue parasite burdens. In male bass positive correlations of THg were observed with plasma vitellogenin and hepatic transcript abundance of estrogen receptor β1 and androgen receptor α, while there was a negative association with estrogen receptors α and β2 and androgen receptors β. In female bass there was a negative correlation between THg and plasma vitellogenin as well as hepatic transcript abundance of vitellogenin, choriogenin, estrogen receptor β2 and 17β hydroxysteroid dehydrogenase. Associations of THg concentrations with various biological indicators suggest mercury may be an important environmental stressor contributing to the observed adverse effects in smallmouth bass populations.
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Affiliation(s)
- Vicki S Blazer
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Road, Kearneysville, WV, 25430, USA.
| | - Heather L Walsh
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Road, Kearneysville, WV, 25430, USA
| | - Adam J Sperry
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Road, Kearneysville, WV, 25430, USA
| | - Brenna Raines
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Road, Kearneysville, WV, 25430, USA
| | - 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
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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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Walsh HL, Gordon SE, Sperry AJ, Kashiwagi M, Mullican J, Blazer VS. A case study: temporal trends of environmental stressors and reproductive health of smallmouth bass (Micropterus dolomieu) from a site in the Potomac River Watershed, Maryland, USA. ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:1536-1553. [PMID: 36454361 PMCID: PMC9729326 DOI: 10.1007/s10646-022-02605-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Decades of poor reproductive success and young-of-the-year survival, combined with adult mortality events, have led to a decline in the smallmouth bass (SMB; Micropterus dolomieu) population in sections of the Potomac River. Previous studies have identified numerous biologic and environmental stressors associated with negative effects on SMB health. To better understand the impact of these stressors, this study was conducted at the confluence of Antietam Creek and the Potomac River from 2013 to 2019 to identify temporal changes associated with SMB reproductive health. Surface water samples were collected and analyzed for over 300 organic contaminants, including pesticides, phytoestrogens, pharmaceuticals, hormones and total estrogenicity (E2Eq). Adult SMB were collected and sampled for multiple endpoints, including gene transcripts associated with reproduction (molecular), histopathology (cellular), and organosomatic indices (tissue). In males, biomarkers of estrogenic endocrine disruption, including testicular oocytes (TO) and plasma vitellogenin (Vtg) were assessed. Numerous agriculture-related contaminants or land use patterns were associated with gene transcript abundance in both male and female SMB. Positive associations between pesticides in the immediate catchment with TO severity and E2Eq with plasma Vtg in males were identified. In males, the prevalence of TO and detectable levels of plasma Vtg, liver vitellogenin transcripts (vtg) and testis vtg were high throughout the study. Peaks of complex mixtures of numerous contaminants occurred during the spring/early summer when spawning and early development occurs and to a lesser extent in fall/winter during recrudescence. Management practices to reduce exposure during these critical and sensitive periods may enhance reproductive health of these economically important sportfishes.
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Affiliation(s)
- Heather L Walsh
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Rd., Kearneysville, WV, 25430, USA.
| | - Stephanie E Gordon
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Rd., Kearneysville, WV, 25430, USA
| | - Adam J Sperry
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Rd., Kearneysville, WV, 25430, USA
| | - Michael Kashiwagi
- Maryland Department of Natural Resources, Fishing and Boating Services, 10932 Putman Rd., Thurmont, MD, 21788, USA
| | - John Mullican
- Maryland Department of Natural Resources, Fishing and Boating Services, 20901 Fish Hatchery Rd., Hagerstown, MD, 21740, USA
| | - Vicki S Blazer
- U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 11649 Leetown Rd., Kearneysville, WV, 25430, USA
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Moslemi-Aqdam M, Baker LF, Baltzer JL, Branfireun BA, Evans MS, Laird BD, Low G, Low M, Swanson HK. Understanding among-lake variability of mercury concentrations in Northern Pike (Esox lucius): A whole-ecosystem study in subarctic lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 822:153430. [PMID: 35090925 DOI: 10.1016/j.scitotenv.2022.153430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/04/2022] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Mercury concentrations ([Hg]) in fish reflect complex biogeochemical and ecological interactions that occur at a range of spatial and biological scales. Elucidating these interactions is crucial to understanding and predicting fish [Hg], particularly at northern latitudes, where environmental perturbations are having profound effects on land-water-animal interactions, and where fish are a critical subsistence food source. Using data from eleven subarctic lakes that span an area of ~60,000 km2 in the Dehcho Region of Northwest Territories (Canada), we investigated how trophic ecology and growth rates of fish, lake water chemistry, and catchment characteristics interact to affect [Hg] in Northern Pike (Esox lucius), a predatory fish of widespread subsistence and commercial importance. Results from linear regression and piecewise structural equation models showed that 83% of among-lake variability in Northern Pike [Hg] was explained by fish growth rates (negative) and concentrations of methyl Hg ([MeHg]) in benthic invertebrates (positive). These variables were in turn influenced by concentrations of dissolved organic carbon, MeHg (water), and total Hg (sediment) in lakes, which were ultimately driven by catchment characteristics. Lakes in relatively larger catchments and with more temperate/subpolar needleleaf and mixed forests had higher [Hg] in Northern Pike. Our results provide a plausible mechanistic understanding of how interacting processes at scales ranging from whole catchments to individual organisms influence fish [Hg], and give insight into factors that could be considered for prioritizing lakes for monitoring in subarctic regions.
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Affiliation(s)
| | - Leanne F Baker
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | | | | | - Marlene S Evans
- Water Science and Technology Directorate, Environment and Climate Change Canada, Saskatoon, SK, Canada
| | - Brian D Laird
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - George Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Mike Low
- Dehcho Aboriginal Aquatic Resources & Oceans Management, Hay River, NT, Canada
| | - Heidi K Swanson
- Department of Biology, University of Waterloo, Waterloo, ON, Canada; Water Institute, University of Waterloo, Waterloo, ON, Canada
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Pavla S, Danka H, Premysl M, Denisa M, Kristyna M, Zdenka S. Do the total mercury concentrations detected in fish from Czech ponds represent a risk for consumers? Sci Rep 2022; 12:553. [PMID: 35017608 PMCID: PMC8752681 DOI: 10.1038/s41598-021-04561-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/21/2021] [Indexed: 11/08/2022] Open
Abstract
Mercury is one of the important pollutants of the environment. Therefore, it's necessary to monitor quantity of mercury especially in aquatic ecosystems. The main goal of the presented study was to compare the content of total mercury in tissues of fish coming from the Czech Republic, an important carp exporter, with focus on comparison of mercury content between 3 different ponds, its comparison between different fish species and between different tissues of the same species, and estimation whether the mercury content in tissues meets the limit given in the Commission Regulation (EC) No. 1881/2006 or not. Total mercury concentration was measured in 90 fish specimen sampled from three ponds (Velky Kocelovicky, Mysliv and Zehunsky) in autumn 2018. The values of total mercury in fish tissues was measured by atomic absorption spectrometry. The content of total mercury in the tissues decreased as follows: muscle > liver > gonads > scales. The highest average content of total mercury in muscle was 0.1517 ± 0.0176 mg/kg coming from pike caught in Velky Kocelovicky pond. In contrast, the lowest average content of total mercury in muscle 0.0036 ± 0.0003 mg/kg was found in carp tissue coming from the locality of Zehunsky pond. We confirmed that the predatory fish are more exposed to mercury than non-predatory fish. None of the monitored localities exceeded the set regulatory limit. Thus, our study shows that fish coming from these ponds are safe in terms of total mercury content.
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Affiliation(s)
- Sehonova Pavla
- Department of Animal Protection and Welfare & Veterinary Public Health, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic.
| | | | - Mikula Premysl
- Department of Animal Protection and Welfare & Veterinary Public Health, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
| | - Medkova Denisa
- Department of Animal Protection and Welfare & Veterinary Public Health, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
- Department of Zoology, Fisheries, Hydrobiology and Apiculture, Faculty of Agrisciences, Mendel University in Brno, Brno, Czech Republic
| | - Malacova Kristyna
- Department of Animal Protection and Welfare & Veterinary Public Health, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
| | - Svobodova Zdenka
- Department of Animal Protection and Welfare & Veterinary Public Health, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
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Arinaitwe K, Koch A, Taabu-Munyaho A, Marien K, Reemtsma T, Berger U. Spatial profiles of perfluoroalkyl substances and mercury in fish from northern Lake Victoria, East Africa. CHEMOSPHERE 2020; 260:127536. [PMID: 32683018 DOI: 10.1016/j.chemosphere.2020.127536] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
There is an acute deficit of data on per- and polyfluoroalkyl substances (PFASs) and mercury (Hg) in the open waters of Lake Victoria, East Africa, relative to nearshore areas. We analyzed stable isotopes (δ15N and δ13C), PFASs and Hg in Nile Perch and Nile Tilapia muscle and liver samples from nearshore and open lake locations from the Ugandan part of the lake. The δ15N values of Nile Perch muscle indicated a higher trophic level for samples from the open lake than from nearshore locations. Averages of ∑PFAS concentrations in Nile Perch muscle and liver (0.44 and 1.75 ng/g ww, respectively) were significantly higher than in Nile Tilapia (0.24 and 0.50 ng/g ww, respectively). ∑PFAS concentrations in muscle of open lake Nile Perch were significantly higher than for nearshore samples. A similar observation was made for total mercury concentrations in muscle (THg_Muscle) of Nile Perch. THg was dominated by methyl mercury (MeHg+, 22-124 ng/g ww) and mercuric mercury (Hg2+, <MDL-29 ng/g ww) in Nile Perch muscle. Strong correlation between MeHg+ and some PFASs (e.g. PFOS: r = 0.704, P = 0.016) suggested similar exposure routes or factors. Estimated human daily intake values of PFOS from fish consumption were below international limits whereas for MeHg+, the US EPA reference dose was exceeded.
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Affiliation(s)
- Kenneth Arinaitwe
- Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318, Leipzig, Germany; Makerere University, Department of Chemistry, P.O. Box 7062, Kampala, Uganda.
| | - Arne Koch
- Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318, Leipzig, Germany.
| | - Anthony Taabu-Munyaho
- Uganda National Fisheries Resources Research Institute (NaFIRRI), P.O. Box 343, Jinja, Uganda.
| | - Karsten Marien
- Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318, Leipzig, Germany.
| | - Thorsten Reemtsma
- Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318, Leipzig, Germany; University of Leipzig, Institute for Analytical Chemistry, Linnéstrasse 3, 04103, Leipzig, Germany.
| | - Urs Berger
- Helmholtz Centre for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstrasse 15, 04318, Leipzig, Germany.
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