methylmercury Articles
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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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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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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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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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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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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 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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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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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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Influence of a chlor‐alkali Superfund site on mercury bioaccumulation in periphyton and Low‐trophic level fauna
In Berlin, NH, the Androscoggin River flows adjacent to a former chlor‐alkali facility that is a US EPA Superfund site and source of mercury (Hg) to the river. A study was conducted to determine the fate and bioaccumulation of methylmercury (MeHg) to lower trophic‐level taxa in the river. Surface sediment directly adjacent to the source showed significantly elevated MeHg (10–40x increase, ...
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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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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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Mercury bioaccumulation in dragonflies (Odonata: Anisoptera): Examination of life stages and body regions
Dragonflies (Odonata: Anisoptera) are an important component of both aquatic and terrestrial food webs and are vectors for methylmercury (MeHg) biomagnification. Variations in mercury content with life stage and body regions may affect the relative transfer of mercury to aquatic or terrestrial food webs; however, there has been little research on this subject. Also, little is known about ...
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Disparity between state fish consumption advisory systems for methylmercury and US Environmental Protection Agency recommendations: A case study of the south central United States
Fish consumption advisories are used to inform citizens in the United States about noncommercial game fish with hazardous levels of methylmercury (MeHg). The US Environmental Protection Agency (USEPA) suggests issuing a fish consumption advisory when concentrations of MeHg in fish exceed a human health screening value of 300 ng/g. However, states have authority to develop their own systems for ...
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Hepatic and nephric mercury and selenium concentrations in common mergansers Mergus merganser from Baltic Region, Europe
Mercury (Hg) and selenium (Se) concentrations and their relationships in wild aquatic vertebrates have been investigated in areas with appropriate or excessive Se levels, mainly in North America. Generally, total mercury (THg) is determined in biota, although piscivorous vertebrates are most affected by dietborne methylmercury (MeHg). Mercury detoxification is based largely on production of ...
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Ebullition rates and mercury concentrations in St. Lawrence River sediments and a benthic invertebrate
Ebullition, the release of gas from anaerobic decomposition in sediments, was recorded in a mercury‐contaminated depositional zone (zone 1) of the St. Lawrence River area of concern in Cornwall, Ontario, Canada. Our aim was to test if this disturbance affected the bioavailability of total mercury (THg) and methylmercury (MeHg) in surficial sediments to a benthic invertebrate (Echinogammarus ...
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Mercury Contamination in Turtles and Implications for Human Health
Mercury contamination threatens many ecosystems worldwide. Methylmercury bioaccumlates at each trophic level, and biomagnifies within individuals over time. Long-lived turtles often occupy high trophic positions and are likely to accumulate mercury in contaminated habitats. Millions of turtles worldwide are sold in Asia for human consumption, and consumers may be at risk if turtles contain high ...
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Physical Controls on Total and Methylmercury Concentrations in Streams and Lakes of the Northeastern USA
The physical factors controlling total mercury (HgT) and methylmercury (MeHg) concentrations in lakes and streams of northeastern USA were assessed in a regional data set containing 693 HgT and 385 corresponding MeHg concentrations in surface waters. Multiple regression models using watershed characteristics and climatic variables explained 38% or less of the variance in HgT and MeHg. Land cover ...
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