methylmercury Articles
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Maternal transfer of inorganic mercury and methylmercury in aquatic and terrestrial arthropods
The transfer of mercury from female to offspring plays an important role in its accumulation and toxicity during early development. To quantify the transfer of inorganic mercury and methylmercury from female arthropods to their eggs, we collected and analyzed brine shrimp (Artemia franciscana), wolf spiders (Alopecosa spp.), and their attached eggs from aquatic and terrestrial ecosystems at ...
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The polychaete worm Nereis diversicolor increases mercury lability and methylation in intertidal mudflats
The polychaete worm Nereis diversicolor engineers its environment by creating oxygenated burrows in anoxic intertidal sediments. We carried out a laboratory microcosm experiment to test the impact of polychaete burrowing and feeding activity on the lability and methylation of mercury in sediments from the Bay of Fundy, Canada. The concentration of labile inorganic mercury and methylmercury in ...
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Relation among mercury concentration, growth rate and condition of northern pike: A tautology resolved?
Methylmercury is a bioaccumulative contaminant that biomagnifies in aquatic food webs and adversely affects the health of freshwater fish. Previous studies have documented an inverse relation between fish condition and concentration of mercury in fish. However, this relation may be a result of slow‐growing fish accumulating large amounts of methylmercury rather than the effects of ...
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Factors Influencing Mercury in Freshwater Surface Sediments of Northeastern North America
We report on an inventory and analysis of sediment mercury (Hg) concentrations from 579 sites across northeastern North America. Sediment Hg concentrations ranged from the limit of detection ca. 0.01–3.7 g g–1 (dry weight, d.w.), and the average concentration was 0.19 g g–1 (d.w.) Sediment methylmercury concentrations ranged from 0.15 to 21 ng g–1 (d.w.) and the mean concentration was 3.83 ng g–1 ...
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Dissolved organic matter reduces algal accumulation of methylmercury
Dissolved organic matter (DOM) significantly decreased accumulation of methylmercury (MeHg) by the diatom Cyclotella meneghiniana in laboratory experiments. Live diatom cells accumulated two to four times more MeHg than dead cells, indicating that accumulation may be partially an energy‐requiring process. Methylmercury enrichment in diatoms relative to ambient water was measured by a volume ...
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Saltwater flotation for more efficient matrix separation of wetland macroinvertebrates does not affect total mercury or methylmercury concentrations
We compared benthic wetland invertebrate matrix separation techniques (handpicking vs. saltwater flotation) to test for effects on invertebrate mercury concentrations. Neither total mercury nor methylmercury concentrations differed significantly between techniques across eight taxa. Matrix separation by the flotation technique took significantly less time and resulted in significantly greater ...
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Development neurotoxicity: implications of methylmercury research
The causes of neurodevelopmental disorders are mostly unknown. Exposure to certain chemicals during early foetal development can cause permanent brain injury at doses much lower than those that affect the adult brain. Recent epidemiological evidence on methylmercury has shown adverse effects at exposure levels previously thought to be safe. Major obstacles in this research field include ...
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Lifelong exposure to methylmercury disrupts stress‐induced corticosterone response in zebra finches (Taeniopygia guttata)
Mercury can disrupt the endocrine systems of mammals and fish, but little is known about its effects on avian hormones. We employed an experimental manipulation to show that methylmercury suppresses the stress‐induced corticosterone response in birds, an effect previously unreported in the literature. Corticosterone regulates many normal metabolic processes, such as the maintenance of proper ...
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Biomagnification of mercury through the benthic food webs of a temperate estuary: Masan Bay, Korea
The authors examined food web magnification factors of total mercury (THg) and methylmercury (MeHg) for the benthic organisms in Masan Bay, a semiclosed, temperate estuary located on the southeastern coast of Korea. For benthic invertebrates, concentrations of THg and MeHg (%MeHg) ranged from 9.57 to 195 and 2.56 to 111 ng/g dry weight (12.2–85.6%), respectively. Benthic fish THg and MeHg (%MeHg) ...
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An environmental problem hidden in plain sight? Small Human‐made ponds, emergent insects, and mercury contamination of biota in the Great Plains
Mercury (Hg) contamination of small human‐made ponds and surrounding terrestrial communities may be 1 of the largest unstudied Hg‐pollution problems in the United States. Humans have built millions of small ponds in the Great Plains of the United States, and these ponds have become contaminated with atmospherically deposited mercury. In aquatic ecosystems, less toxic forms of Hg deposited from ...
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Mercury in Northeastern North America: A synthesis of Existing Databases
A large number of datasets representing mercury (Hg) levels in northeastern North America were assembled in a standardized format between 2000 and 2003. Based on support from the Northeastern States Research Cooperative, scientists annually gathered and developed an operational template to collaboratively analyze and interpret these data for a series of peer-reviewed publications. The diverse ...
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Effect of laying sequence on egg mercury in captive zebra finches: An interpretation considering individual variation
Bird eggs are widely used as noninvasive bioindicators for environmental mercury availability. However, previous studies have found varying relationships between laying sequence and egg mercury concentrations. Some studies have reported that the mercury concentration is higher in first‐laid eggs or declines across the laying sequence, whereas in other studies mercury concentration was not ...
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Biological and chemical influences on trace metal toxicity and bioaccumulation in the marine and estuarine environment
For several trace metals, bioavailability and toxicity are controlled by both chemical (free ion) and physiological effects. The role of salinity in trace metal uptake (particularly cadmium) could be explained by a mixture of free ion and biological effects. Mercury (Hg) and methylmercury (MMHg) bioaccumulation is different from that of other metals because uptake of the free metal ion via ...
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Methylmercury biomagnification in an Arctic pelagic food web
Mercury (Hg) is a toxic element that enters the biosphere from natural and anthropogenic sources, and emitted gaseous Hg enters the Arctic from lower latitudes by long‐range transport. In aquatic systems, anoxic conditions favor the bacterial transformation of inorganic Hg to methylmercury (MeHg), which has a greater potential for bioaccumulation than inorganic Hg and is the most toxic form of ...
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Mercury Detection
What is Mercury? Mercury is a neurotoxin. Mercury is a naturally-occurring chemical element found in rock in the earth’s crust, including in deposits of coal. On the periodic table, it has the symbol “Hg” and its atomic number is 80. It exists in several forms: elemental (metallic) mercury, inorganic mercury compounds, and methylmercury and other organic compounds. ...
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Modeled methylmercury exposure and risk from rice consumption for vulnerable populations in a traditional fish‐eating area in China
The circulation of rice from contaminated areas could escalate exposure risk from a local problem to a national issue and affect a wider population beyond the region of origin, as confirmed by the “Poison Rice Incident” in May 2013 in Guangzhou, China. In this study, the authors' established a food chain model based on the aquivalence method to identify major sources of methylmercury (MeHg), ...
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Mercury in fish: a critical examination of gold mining and human contamination in Ghana
This study examines the knowledge of miners, fishermen, fish sellers, and fish buyers regarding the linkages between elemental mercury, methylmercury, fish consumption, and health risks in and around mining areas in Ghana. While findings suggest that a clear grasp of the impacts of mercury on human health is lacking, few potentially polluted fish are consumed in the mining areas. Most customers ...
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An overview of recent IAEA projects on mercury in non-marine environments
Nuclear and isotopic techniques are unique tools for studying mercury contamination and cycling in various environments. Therefore, the International Atomic Energy Agency (IAEA) has been supporting the use of nuclear and complementary analytical techniques (mainly neutron activation analysis, inductively coupled plasma – mass spectrometry and atomic absorption spectrometry), and application of ...
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Toxicity of dietary methylmercury to fish: Derivation of ecologically meaningful threshold concentrations
Threshold concentrations associated with adverse effects of dietary exposure to methylmercury (MeHg) were derived from published results of laboratory studies on a variety of fish species. Adverse effects related to mortality were uncommon, whereas adverse effects related to growth occurred only at dietary MeHg concentrations exceeding 2.5 µg g−1 wet weight. Adverse effects on behavior of fish ...
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Derivation of screening benchmarks for dietary methylmercury exposure for the common loon (Gavia immer): Rationale for use in ecological risk assessment
The current understanding of methylmercury (MeHg) toxicity to avian species has improved considerably in recent years and indicates that exposure to environmentally relevant concentrations of MeHg through the diet can adversely affect various aspects of avian health, reproduction, and survival. Because fish‐eating birds are at particular risk for elevated MeHg exposure, the authors surveyed the ...
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