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1

Levels of Cadmium, Lead, Mercury and 137Caesium in Caribou (Rangifer tarandus) Tissues from Northern Québec  

Microsoft Academic Search

Levels of cadmium (Cd), lead (Pb) and total mercury (Hg) were assessed in samples of muscle, kidney, and liver from caribou (Rangifer tarandus; n = 317) harvested in two regions of northern Québec between 1994 and 1996. Levels of 137 caesium (137Cs) were also examined in muscle samples. Log concentration of the three metals varied significantly among tissues and was

S. ROBILLARD; G. BEAUCHAMP; G. PAILLARD; D. BÉLANGER

2002-01-01

2

Mercury levels and its chemical form in tissues and organs of seabirds  

Microsoft Academic Search

Liver, muscle, kidney, and feather samples from nine species of seabirds were analyzed for total and organic (methyl) mercury (MM). Total mercury (TM) levels in liver showed great intra- and inter-species variations, with the concentrations varied from 306 µg\\/g (dry weight) in black-footed albatross (Diomedea nigripes) to 4.9 µg\\/g in arctic tern (Sterna paradisaea), while MM levels were less relatively

E. Y. Kim; T. Murakami; K. Saeki; R. Tatsukawa

1996-01-01

3

Comparison of mercury levels in various tissues of albino and pigmented mice treated with two different brands of mercury skin-lightening creams  

Microsoft Academic Search

The use of mercury containing skin-lightening creams are becoming increasingly popular among dark-skinned women. The long term use of certain brands may cause serious health effects over the years. In the present study, we investigated the dermal absorption of mercury and its accumulation in the tissues of albino and pigmented mice treated with two brands of mercury containing skin-lightening creams

Iman Al-Saleh; Neptune Shinwari; Inaam El-Doush; Grisellhi Billedo; Mona Al-Amodi; Fathia Khogali

2004-01-01

4

Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands  

SciTech Connect

The New Jersey Meadowlands are located within the heavily urbanized New York/New Jersey Harbor Estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the Hackensack River and nearby waterways. These extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. Persistent contaminants may pose threats to birds in these habitats, affecting reproduction, egg hatchability, nestling survival, and neurobehavioral development. Metals of concern in the Meadowlands include arsenic, cadmium, chromium, lead, and mercury. These metals were analyzed in eggs, feathers, muscle, and liver of Canada geese (Branta canadensis) breeding in four wetland sites. We sampled geese collected during control culling (n=26) and collected eggs from goose nests (n=34). Levels of arsenic were below the minimum quantification level (MQL) in most samples, and cadmium and mercury were low in all tissues sampled. Chromium levels were high in feather samples. Mercury levels in eggs of Canada geese, an almost exclusively herbivorous species, were lower (mean {+-}SE 4.29{+-}0.30 {mu}g/g wet weight) than in eggs of omnivorous mallards (Anas platyrhynchos), and insectivorous red-winged blackbirds (Agelaius phoeniceus) and marsh wrens (Cistothorus palustris) from the Meadowlands, consistent with trophic level differences. However, lead levels were higher in the goose eggs (161{+-}36.7 ng/g) than in the other species. Geese also had higher levels of lead in feathers (1910{+-}386 ng/g) than those seen in Meadowlands passerines. By contrast, muscle and liver lead levels were within the range reported in waterfowl elsewhere, possibly a reflection of metal sequestration in eggs and feathers. Elevated lead levels may be the result of sediment ingestion or ingestion of lead shot and sinkers. Finally, lead levels in goose liver (249{+-}44.7 ng/g) and eggs (161{+-}36.7 ng/g) may pose a risk if consumed frequently by humans. Mill Creek, the site with the most documented prior contamination, had significantly elevated cadmium, chromium, mercury, and lead in goose tissues. - Highlights: {yields} The NJ Meadowlands include extensive wetlands in the urban NYC metropolitan area. {yields} We analyzed eggs, feathers, muscle, and liver of Canada geese at 4 Meadowlands sites. {yields} As, Cd, and Hg were low in all tissues sampled, while Cr was high in feathers. {yields} Pb was higher in goose eggs and feathers than in other Meadowlands bird species. {yields} Pb in muscle and liver was lower and within the range seen in waterfowl elsewhere.

Tsipoura, Nellie [New Jersey Audubon Society, 11 Hardscrabble Road, Bernardsville, NJ 07924 (United States)] [New Jersey Audubon Society, 11 Hardscrabble Road, Bernardsville, NJ 07924 (United States); Burger, Joanna, E-mail: burger@biology.rutgers.edu [Division of Life Sciences, 604 Allison Road, Piscataway, NJ 08854-8082 (United States) [Division of Life Sciences, 604 Allison Road, Piscataway, NJ 08854-8082 (United States); Environmental and Occupational Health Sciences Institute, Consortium for Risk Evaluation with Stakeholder Participation, Rutgers University, Piscataway, NJ 08854 (United States); Newhouse, Michael [NJ Meadowlands Commission, One DeKorte Park Plaza, Lyndhurst, NJ 07071 (United States)] [NJ Meadowlands Commission, One DeKorte Park Plaza, Lyndhurst, NJ 07071 (United States); Jeitner, Christian [Division of Life Sciences, 604 Allison Road, Piscataway, NJ 08854-8082 (United States) [Division of Life Sciences, 604 Allison Road, Piscataway, NJ 08854-8082 (United States); Environmental and Occupational Health Sciences Institute, Consortium for Risk Evaluation with Stakeholder Participation, Rutgers University, Piscataway, NJ 08854 (United States); Gochfeld, Michael [Environmental and Occupational Health Sciences Institute, Consortium for Risk Evaluation with Stakeholder Participation, Rutgers University, Piscataway, NJ 08854 (United States) [Environmental and Occupational Health Sciences Institute, Consortium for Risk Evaluation with Stakeholder Participation, Rutgers University, Piscataway, NJ 08854 (United States); Environmental and Occupational Medicine. Robert Wood Johnson Medical School, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Mizrahi, David [New Jersey Audubon Society, 11 Hardscrabble Road, Bernardsville, NJ 07924 (United States)] [New Jersey Audubon Society, 11 Hardscrabble Road, Bernardsville, NJ 07924 (United States)

2011-08-15

5

Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands.  

PubMed

The New Jersey Meadowlands are located within the heavily urbanized New York/New Jersey Harbor Estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the Hackensack River and nearby waterways. These extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. Persistent contaminants may pose threats to birds in these habitats, affecting reproduction, egg hatchability, nestling survival, and neurobehavioral development. Metals of concern in the Meadowlands include arsenic, cadmium, chromium, lead, and mercury. These metals were analyzed in eggs, feathers, muscle, and liver of Canada geese (Branta canadensis) breeding in four wetland sites. We sampled geese collected during control culling (n=26) and collected eggs from goose nests (n=34). Levels of arsenic were below the minimum quantification level (MQL) in most samples, and cadmium and mercury were low in all tissues sampled. Chromium levels were high in feather samples. Mercury levels in eggs of Canada geese, an almost exclusively herbivorous species, were lower (mean ±SE 4.29±0.30?g/g wet weight) than in eggs of omnivorous mallards (Anas platyrhynchos), and insectivorous red-winged blackbirds (Agelaius phoeniceus) and marsh wrens (Cistothorus palustris) from the Meadowlands, consistent with trophic level differences. However, lead levels were higher in the goose eggs (161±36.7ng/g) than in the other species. Geese also had higher levels of lead in feathers (1910±386ng/g) than those seen in Meadowlands passerines. By contrast, muscle and liver lead levels were within the range reported in waterfowl elsewhere, possibly a reflection of metal sequestration in eggs and feathers. Elevated lead levels may be the result of sediment ingestion or ingestion of lead shot and sinkers. Finally, lead levels in goose liver (249±44.7ng/g) and eggs (161±36.7ng/g) may pose a risk if consumed frequently by humans. Mill Creek, the site with the most documented prior contamination, had significantly elevated cadmium, chromium, mercury, and lead in goose tissues. PMID:21679937

Tsipoura, Nellie; Burger, Joanna; Newhouse, Michael; Jeitner, Christian; Gochfeld, Michael; Mizrahi, David

2011-08-01

6

Mercury levels in fishes from some Missouri lakes with and without known mercury pollution  

Microsoft Academic Search

Mercurial fungicides used in golf greens can lead to elevated mercury levels in fish from lakes receiving greens drainage. The largemouth bass is the most sensitive indicator with levels ranging from 1-7 mg mercury\\/g of wet tissue in fish taken from lakes that receive drainage from treated greens. Many lakes with no known source of mercury contamination produce bass that

S. R. Koirtyohann; R. Meers; L. K. Graham

1974-01-01

7

Organ mercury levels in infants with omphaloceles treated with organic mercurial antiseptic  

Microsoft Academic Search

Samples of fresh and fixed tissues from infants with exomphalos treated by thiomersal application were analysed for mercury content. The results showed that thiomersal can induce blood and organ levels of organic mercury which are well in excess of the minimum toxic level in adults and fetuses. The analysis of fresh and fixed tissues must be carefully controlled against normal

D. G. Fagan; J S Pritchard; T. W. Clarkson; M. R. Greenwood

1977-01-01

8

Mercury levels in myliobatid stingrays (Batoidea) from the Gulf of California: tissue distribution and health risk assessment.  

PubMed

With the aim of knowing Hg distribution in selected tissues of myliobatid stingrays and assessing health risk to Mexican population, Hg concentration was determined in the muscle and liver of four ray species. Total Hg levels were determined by cold vapor atomic absorption spectrophotometry. With respect to the muscle, devil rays (Mobula spp.) showed lower Hg levels (<0.22 ?g g(-1)) than Rhinoptera steindachneri (0.37?±?0.25 ?g g(-1) wet weight). In the case of the liver, the highest Hg concentration was found in Mobula japanica (0.22?±?0.01 ?g g(-1)). Hg levels in the muscle and liver varied according to the species; in some case, the liver accumulated more Hg than the muscle and the opposite pattern in other cases. R. steindachneri showed a significant difference between both tissues. No significant differences of Hg levels between males and females and between juveniles and adult specimens of R. steindachneri were found. Positive correlation between Hg concentrations and disc width and total weight was not significant for R. steindachneri (Rs??0.05). Batoids showed Hg values below the Mexican (NOM-027-SSA1-1993) limits (1.0 ?g g(-1)) in fishes for human consumption. The species with the highest potential of Hg transfer to human population is R. steindachneri; however, an adult (70 kg) could consume approximately 943 g per week without representing a health risk. Nevertheless, further and continuous monitoring is needed since batoids support an important fishery in Mexican waters, being a food resource and income to coastal communities. PMID:24197561

Escobar-Sánchez, O; Ruelas-Inzunza, J; Patrón-Gómez, J C; Corro-Espinosa, D

2014-03-01

9

Mercury and selected pesticide levels in fish and wildlife of Utah: II. levels of mercury, DDT, DDE, dieldrin and PCB in chukars, pheasants and waterfowl  

Microsoft Academic Search

Summary Levels of mercury and selected pesticides were determined in muscle tissue of chukars, pheasants and waterfowl collected from various regions within the state of Utah. None of the chukar tissue 6% of the pheasant tissue and 4% of the waterfowl tissue analyzed contained mercury concentrations greater than the FDA limit of 0.5 ppm. None of the chukars or pheasants

F. A. Smith; R. P. Sharma; R. I. Lynn; J. B. Low

1974-01-01

10

Mercury baseline levels in Flemish soils (Belgium)  

Microsoft Academic Search

It is important to establish contaminant levels that are normally present in soils to provide baseline data for pollution studies. Mercury is a toxic element of concern. This study was aimed at assessing baseline mercury levels in soils in Flanders. In a previous study, mercury contents in soils in Oost-Vlaanderen were found to be significantly above levels reported elsewhere. For

Filip M. G. Tack; Thomas Vanhaesebroeck; Marc G. Verloo; Kurt Van Rompaey; Eric Van Ranst

2005-01-01

11

Mercury and selected pesticide levels in fish and wildlife of Utah: I. levels of mercury, DDT, DDE, dieldrin and PCB in fish  

Microsoft Academic Search

Summary Levels of mercury and selected pesticides were determined in the muscle tissue of fish obtained from different regions in the state of Utah. The levels of mercury present were generally lower than the guideline limit (0.5 ppm) in most fish except those obtained from one localized area (Willard Bay Reservoir). Predators had the greatest accumulation of mercury. Only small

F. A. Smith; R. P. Sharma; R. I. Lynn; J. B. Low

1974-01-01

12

Mercury Levels in Infants Receiving Routine Immunizations  

MedlinePLUS

... Skip Content Marketing Share this: Main Content Area Mercury Levels in Infants Receiving Routine Immunizations Study I: Infant Metabolism of Thimerosal versus Methyl Mercury NIAID-supported studies at the University of Rochester ...

13

Mercury in fish tissue: Association with other measures of lake quality  

SciTech Connect

This presentation will explore associations between mercury in fish tissue and other measures of lake quality as one method of diagnosing the source or cause of high fish tissue mercury levels. The EMAP-Surface Waters multi-indicator approach helps to make such a diagnosis possible. Correlations between fish tissue mercury data from the 1992 and 1993 EMAP-SW Northeast Pilot studies and corresponding site data from other indicators were found that support specific sources and causes of high mercury levels in fish. Metrics from the stressor indicator (which describe characteristics likely to impact an ecosystem, such as land use) point to a contribution of mercury from atmospheric sources being more important than that from local watershed sources. Lakes with high levels of Hg in fish tissue have less associated local human disturbance: lower population and point source densities and lower percent of total human-disturbed land use in lake watersheds. A positive correlation between runoff and fish mercury levels is also seen, showing the importance of precipitation as at least a contributing factor. Metrics from the water chemistry indicator support correlations seen in other studies between high mercury fish tissue levels and low pH and low acid neutralizing capacity (ANC). Lakes with high mercury fish tissue levels ({>=} 0.2 ppm) were found to have statistically lower water pH and ANC. A correlation was also seen between chemical measures of oligotrophy (lower total-p, total-N, and chlorophyll) and high fish mercury levels, supporting a tissue dilution theory. These as well as other associations are explored.

Yeardley, R. [DynCorp, Cincinnati, OH (United States); Lazorchak, J. [Environmental Protection Agency, Cincinnati, OH (United States)

1995-12-31

14

Mercury in the muscle tissue of fish from three northern Maine lakes  

SciTech Connect

We report the levels of mercury in the muscle tissue of brook trout (Salvelinus fontinalis) and lake trout (S. namaycush) from three northern Maine lakes. Mercury levels in fish from two wilderness lakes in the same drainage basin were compared with each other, and in turn with those in fish from a lake in a separate drainage basin. The fish species composition in one of the wilderness lakes, Cliff Lake, is different from that in the other two lakes, enabling us to analyze the effects of trophic structure on mercury concentration in top carnivores. It is unlikely that mercury from agricultural, geological, or local industrial sources occurs in these lakes.

Akielaszek, J.J.; Haines, T.A.

1981-08-01

15

Mercury accumulation in selected tissues of shrimp Penaeus merguiensis from Musa estuary, Persian Gulf: variations related to sex, size, and season.  

PubMed

The levels of mercury in tissues of Penaeus merguiensis from Musa estuary, northwest of the Persian Gulf, were investigated. This study assessed the relationship between mercury levels in hepatopancrea, gill, and muscle with sex, size, and season. The order of mercury concentrations in tissues of the shrimp P. merguiensis was as follows: hepatopancreas > gill > muscle. There was a positive correlation between mercury concentrations in shrimp species with sex and size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. Also, there was a positive correlation between mercury concentrations in shrimp species with its food source. Therefore, female species feed more on shrimp and plant and are contaminated with high levels of mercury. There was significant difference (p?mercury levels between different seasons; higher mercury levels were found in July (summer season). PMID:24838762

Hosseini, Mehdi; Nabavi, Seyed Mohammad Bagher; Parsa, Yaghoob; Ardashir, Rashid Alijani

2014-09-01

16

Mercury and Selenium in Fish from the Savannah River: Species, Trophic Level, and Locational Differences  

Microsoft Academic Search

Levels of contaminants in fish are of considerable interest because of potential effects on the fish themselves, as well as on other organisms that consume them. In this article we compare the mercury levels in muscle tissue of 11 fish species from the Savannah River, as well as selenium levels because of its known protective effect against mercury toxicity. We

Joanna Burger; Karen F. Gaines; C. Shane Boring; Warren L. Stephens; Joel Snodgrass; Michael Gochfeld

2001-01-01

17

Mercury and fish tissue -- Status of Oregon reservoirs and lakes  

SciTech Connect

The Oregon Department of Environmental Quality monitors contaminants in fish and sediment. Total mercury was analyzed in fish tissue taken from ten water bodies in 1993 and 1994. Mercury was measured in bass (Micropterus salmoides, M. dolomieui), salmonids (Salmo trutta, Oncorhynchus mykiss, O. clarki) and catfish (Ictalurus punctatus, I. nebulosus) in support of health department consumption advisories. Elevated mercury concentrations above the EPA screening value of 0.6 mg/kg wet were found in fish from watersheds with cinnabar geology or historical mining activity. Established bioaccumulation correlations between mercury and species, age, and length were also observed. Results from East Lake, a popular recreational fishery that had not previously been studied, were found to have fish mercury concentrations approaching 3.0 mg/kg wet. Regulatory and fish management issues will also be presented.

Drake, D.; Stifel, B.; DiDomenico, G.; McCartney, R. [Dept. of Environmental Quality, Portland, OR (United States)

1995-12-31

18

Mercury burden of human fetal and infant tissues  

Microsoft Academic Search

The total mercury concentrations in the liver (Hg-L), the kidney cortex (Hg-K) and the cerebral cortex (Hg-C) of 108 children aged 1 day-5 years, and the Hg-K and Hg-L of 46 fetuses were determined. As far as possible, the mothers were interviewed and their dental status was recorded. The results were compared to mercury concentrations in the tissues of adults

G. Drasch; I. Schupp; H. Höfl; R. Reinke; G. Roider

1994-01-01

19

Multi-tissue analyses reveal limited inter-annual and seasonal variation in mercury exposure in an Antarctic penguin community.  

PubMed

Inter-annual variation in tissue mercury concentrations in birds can result from annual changes in the bioavailability of mercury or shifts in dietary composition and/or trophic level. We investigated potential annual variability in mercury dynamics in the Antarctic marine food web using Pygoscelis penguins as biomonitors. Eggshell membrane, chick down, and adult feathers were collected from three species of sympatrically breeding Pygoscelis penguins during the austral summers of 2006/2007-2010/2011. To evaluate the hypothesis that mercury concentrations in penguins exhibit significant inter-annual variation and to determine the potential source of such variation (dietary or environmental), we compared tissue mercury concentrations with trophic levels as indicated by ?(15)N values from all species and tissues. Overall, no inter-annual variation in mercury was observed in adult feathers suggesting that mercury exposure, on an annual scale, was consistent for Pygoscelis penguins. However, when examining tissues that reflected more discrete time periods (chick down and eggshell membrane) relative to adult feathers, we found some evidence of inter-annual variation in mercury exposure during penguins' pre-breeding and chick rearing periods. Evidence of inter-annual variation in penguin trophic level was also limited suggesting that foraging ecology and environmental factors related to the bioavailability of mercury may provide more explanatory power for mercury exposure compared to trophic level alone. Even so, the variable strength of relationships observed between trophic level and tissue mercury concentrations across and within Pygoscelis penguin species suggest that caution is required when selecting appropriate species and tissue combinations for environmental biomonitoring studies in Antarctica. PMID:25085270

Brasso, Rebecka L; Polito, Michael J; Emslie, Steven D

2014-10-01

20

Using river distance and existing hydrography data can improve the geostatistical estimation of fish tissue mercury at unsampled locations.  

PubMed

Mercury in fish tissue is a major human health concern. Consumption of mercury-contaminated fish poses risks to the general population, including potentially serious developmental defects and neurological damage in young children. Therefore, it is important to accurately identify areas that have the potential for high levels of bioaccumulated mercury. However, due to time and resource constraints, it is difficult to adequately assess fish tissue mercury on a basin wide scale. We hypothesized that, given the nature of fish movement along streams, an analytical approach that takes into account distance traveled along these streams would improve the estimation accuracy for fish tissue mercury in unsampled streams. Therefore, we used a river-based Bayesian Maximum Entropy framework (river-BME) for modern space/time geostatistics to estimate fish tissue mercury at unsampled locations in the Cape Fear and Lumber Basins in eastern North Carolina. We also compared the space/time geostatistical estimation using river-BME to the more traditional Euclidean-based BME approach, with and without the inclusion of a secondary variable. Results showed that this river-based approach reduced the estimation error of fish tissue mercury by more than 13% and that the median estimate of fish tissue mercury exceeded the EPA action level of 0.3 ppm in more than 90% of river miles for the study domain. PMID:21842901

Money, Eric S; Sackett, Dana K; Aday, D Derek; Serre, Marc L

2011-09-15

21

Total mercury distribution in different tissues of six species of freshwater fish from the Kpong hydroelectric reservoir in Ghana.  

PubMed

Total mercury concentrations were determined in seven tissues of 38 fish samples comprising six species from the Kpong hydroelectric reservoir in Ghana by cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer. Mercury concentration in all the tissues ranged from 0.005 to 0.022 ?g/g wet weight. In general, the concentration of mercury in all the tissues were decreasing in the order; liver?>?muscle?>?intestine?>?stomach?>?gonad?>?gill?>?swim bladder. Mercury concentration was generally greater in the tissues of high-trophic-level fish such as Clarotes laticeps, Mormyrops anguilloides and Chrysichthys aurutus whereas low-trophic-level fish such as Oreochromis niloticus recorded low mercury concentration in their tissues. The results obtained for total mercury concentration in the muscle tissues analysed in this study are below the WHO/FAO threshold limit of 0.5 ?g/g. This suggests that the exposure of the general public to Hg through fish consumption can be considered negligible. PMID:21713471

Atta, Alhassan; Voegborlo, Ray Bright; Agorku, Eric Selorm

2012-05-01

22

Content of non-mercury-associated selenium in human tissues  

Microsoft Academic Search

Recent studies have shown that at a higher mercury (Hg) burden, the molar ratio of selenium (Se) and Hg in tissues tends to\\u000a approximate 1:1 by the formation of biologically largely inert adducts. From the toxicological standpoint, this trapping of\\u000a free Hg is welcome. However, this binding of Se to Hg reduces the portion of Se in tissues, which is

G. Drasch; S. Mailänder; C. Schlosser; G. Roider

2000-01-01

23

Determination of mercury by cold-vapor technique in several tissues of treated American red crayfish (Procambarus clarkii)  

SciTech Connect

Adult intermolt specimens of American red crayfish (Procambarus clarkii) collected from Lake Albufera (Valencia, Spain), were exposed to mercury during 96 h. The Hg-concentrations used were 50, 100, and 250 ..mu..g Hg/l as Cl/sub 2/Hg. The content of mercury in muscle, midgut gland, antennal glands and gills was investigated. Determinations of mercury were made by cold-vapor technique and AAS. The mercury levels in all examined tissues increased significantly with increasing Hg-concentration in the water.

Del Ramo, J.; Pastor, A.; Diaz-Mayans, J.; Medina, J.; Torreblanca, A.

1988-01-01

24

A simple {sup 197}Hg RNAA procedure for the determination of mercury in urine, blood, and tissue  

SciTech Connect

Mercury has been implicated as a causal agent in such central nervous system diseases as Alzheimer`s and Parkinson`s. Consequently, there has been increased interest in the determination of ultra-trace-level mercury in biological matrices, especially in tissue. While such nonnuclear techniques as cold vapor atomic absorption spectrometry and cold vapor atomic fluorescence spectrometry have been employed routinely for mercury determinations in urine and blood, there is a paucity of nonnuclear techniques for the determination of mercury in the low parts-per-billion range in biological tissue. As pointed out by Fardy and Warner, instrumental and radiochemical neutron activation analysis (INAA and RNAA) require no blank determinations in contrast to nonnuclear analytical techniques employing digestion and/or chemical operations. Therefore, INAA and RNAA become the obvious choices for determination of ultra-trace levels of mercury in tissue. Most separation methods reported in the literature require different and separate methodologies for mercury determinations in urine, blood, or tissue. The purposes of this study are to develop a single methodology for the determination of low levels of mercury in all biological matrices by RNAA and to optimize parameters necessary for an efficacious trace-level determination. Previously, few studies have taken into account the effects of the Szilard-Chalmers reactions of the radioactivatable analyte within a biological matrix. It also would appear that little attention has been given to the optimum postirradiation carrier concentration of the analyte species necessary. This study discusses these various considerations.

Blotcky, A.J. [VA Medical Center, Omaha, NE (United States); Rack, E.P.; Meade, A.G. [Univ. of Nebraska, Lincoln, NE (United States)] [and others

1995-12-31

25

Factors affecting the accumulation and removal of mercury from tissues of the American oyster Crassostrea virginica  

Microsoft Academic Search

Adult oysters, Crassostrea virginica (Gmelin) were held in seawater containing 10 or 100 ppb mercury in the form of mercuric acetate for 45 days. Mercury concentration in tissues was determined by analysis of individually homogenized oyster meats using wet digestion and flameless absorption spectrophotometry. After 45 days, average mercury tissue concentration was 91,600 and 12,100 ppb in the 100 and

P. A. Cunningham; M. R. Tripp

1975-01-01

26

Wavelengths, Energy Level Classifications, and Energy Levels for the Spectrum of Neutral Mercury  

E-print Network

Wavelengths, Energy Level Classifications, and Energy Levels for the Spectrum of Neutral Mercury E A comprehensive critically evaluated compilation of the most accurate wavelength measurements for classified lines wavelengths; atomic wave numbers; energy level classifications; infrared wavelengths; mercury; ultraviolet

Magee, Joseph W.

27

Mercury concentrations in deer mouse (Peromyscus maniculatus) tissues from Isle Royale National Park  

E-print Network

Mercury concentrations in deer mouse (Peromyscus maniculatus) tissues from Isle Royale National National Park, a protected area in Lake Superior. Abstract We used deer mice (Peromyscus maniculatus rights reserved. Keywords: Peromyscus; Mercury; Isle Royale; Biomagni®cation; Terrestrial bioaccumulation

28

A comparison of mercury levels in feathers and eggs of osprey (Pandion haliaetus) in the North American Great Lakes.  

PubMed

Osprey (Pandion haliaetus) eggs and chick feathers were collected for mercury analysis from nests at four Great Lakes study areas in Ontario (three "naturally formed" lakes in southern Ontario and one reservoir in northern Ontario) and two New Jersey study areas in 1991-1994. Adult osprey feathers were sampled from three Great Lakes study areas in 1991. Feathers sampled from chicks (approximately 28-35 days old) appear to be better indicators of local contaminant conditions since spatial patterns of mercury in known prey, yellow perch (Perca flavescens), also collected in these areas, were more similar to chick feathers than to eggs. Mercury levels were less variable in chick feathers than in eggs. Estimates of biomagnification factors using prey of known size at these areas were also less variable in feathers than in eggs. At naturally formed lakes, no significant correlation in mercury levels between eggs and chick feathers from the same nest was apparent, suggesting that the source of mercury contamination was not the same in these two tissues: mercury levels in eggs reflect mercury acquired on the breeding grounds, wintering grounds, and migratory route; mercury levels in chick feathers reflect local dietary conditions on the breeding grounds. Mercury levels in both osprey eggs and chick feathers were higher at the Ogoki Reservoir than at naturally formed lakes. Adult osprey feathers had higher mercury concentrations than chick feathers. Mercury levels in osprey eggs, chick feathers, and adult feathers did not approach levels associated with toxic reproductive effects. PMID:9419264

Hughes, K D; Ewins, P J; Clark, K E

1997-11-01

29

Cinnabar is different from mercuric chloride in mercury absorption and influence on the brain serotonin level.  

PubMed

The toxicity of cinnabar, a naturally occurring mercury sulphide (HgS), has long been referred to soluble mercury chloride (HgCl2 ). To investigate whether the speciation of mercury plays a role in its disposition and toxicity, we hereby investigated and compared cinnabar with soluble HgCl2 and pure insoluble HgS in mice on mercury absorption, tissue distribution and in relation to the biological effects. The male C57BL/6J mice were treated by oral administration of various doses of cinnabar, with 0.01 g/kg of HgCl2 for comparison, or the same dose of cinnabar or pure HgS (0.1 g/kg), once a day for 10 consecutive days. The total mercury contents in serum and tissue (brain, kidney, liver) were measured by atomic fluorescence spectrometer (AFS). The biological effects investigated involved monoamine neurotransmitters (serotonin, 5-HT) in brain as an indicator of therapeutic function, and serum alanine transaminase (ALT) as a marker of hepatic damage, blood urea nitrogen (BUN) and serum creatinine as markers for renal function. The mercury absorption of cinnabar or HgS was much less than that of HgCl2 . The mercury levels in brains of the cinnabar group were only slightly changed and kept in a steady-state with the dose elevated. Cinnabar or HgS suppressed brain 5-HT levels. HgCl2 could not cause any changes in brain 5-HT although the mercury level increased considerably. The results revealed that cinnabar or HgS is markedly different from HgCl2 in mercury absorption, tissue distribution and influence on brain 5-HT levels, which suggests that the pharmacological and/or toxicological effects of cinnabar undertake other pathways from mercuric ions. PMID:23302034

Wang, Qi; Yang, Xiaoda; Zhang, Baoxu; Yang, Xiuwei; Wang, Kui

2013-06-01

30

Histochemical demonstration of two mercury pools in trout tissues: mercury in kidney and liver after mercuric chloride exposure  

SciTech Connect

Juvenile rainbow trout (Salmo gairdneri) were exposed to 100 ppb mercury (as HgCl/sub 2/) in the water for 14 days. Concentrations of mercury in water and fish organs were monitored using radiolabeled mercury. Tissues from kidney and liver were fixed, and sections were developed by autometallography, a method whereby accumulations of mercury sulfides and/or mercury selenides are silver amplified. In the kidney, mercury was found within lysosomes and extracellularly in the basal lamina of proximal tubules. In the liver, mercury was found within lysosomes of the hepatocytes. Additional groups of mercury-exposed trout were subjected to selenium (as Na/sub 2/SeO/sub 3/), administered intraperitoneally 2 hr before fixation. Following this treatment, additional mercury could be visualized in the kidney circulatory system, including glomeruli, and in the nucleus and endoplasmic reticulum of liver cells. It is suggested that the mercury visualized prior to selenium treatment represents inorganic mercury, while additional mercury visualized after selenium administration represents an organic form.

Baatrup, E.; Nielsen, M.G.; Danscher, G.

1986-12-01

31

Bioaccumulation of trace mercury in trophic levels of benthic, benthopelagic, pelagic fish species, and sea birds from Arvand River, Iran.  

PubMed

In this study, concentration of mercury was determined in the trophic levels of benthic, benthopelagic, pelagic fish species, and river birds from Arvand River, located in the Khuzestan province in the lowlands of southwestern Iran at the head of the Persian Gulf. The order of mercury concentrations in tissues of the fish species was as follows: liver>gill>muscle and in tissues of the kingfisher species was as follows: feather>liver>kidney>muscle. Therefore, liver in fish and feather in kingfisher exhibited higher mercury concentration than the other tissues. There was a positive correlation between mercury concentrations in fish and kingfisher species with size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. The results of this study show that the highest mean mercury level were found in the kingfisher (Anas crecca), followed by benthic (Epinephelus diacanthus), benthopelagic (Chanos chanos), and pelagic fish (Strongylura strongylura). Mean value of mercury in fish species, S. strongylura were (0.61 ?g g(-1) dry weight), C. chanos (0.45 ?g g(-1) dry weight), E. diacanthus (0.87 ?g g(-1) dry weight), and in kingfisher species A. crecca was (2.64 ?g g(-1) dry weight). Significant correlation between mercury concentration in fish and kingfisher may be related to high variability of mercury in the fish. PMID:24174062

Hosseini, Mehdi; Nabavi, Seyed Mohammad Bagher; Parsa, Yaghob

2013-12-01

32

Mercury exposure in French Guiana: Levels and determinants  

SciTech Connect

Mercury is used widely for gold extraction in French Guiana and throughout the entire Amazon basin. To evaluate contamination among the general population, the authors chose individuals who attended 13 health centers and maternity hospitals dispersed geographically across the territory and served Guiana`s different populations. Five hundred individuals (109 pregnant women, 255 other adults, and 136 children) who received care at one of the centers were selected randomly for this study. Each individual answered a questionnaire and provided a hair sample. The authors determined mercury in hair with atomic absorption spectrometry. The following mean levels of mercury were observed: 1.6 {micro}g/g among pregnant women; 3.4 {micro}g/g among other adults; and 2.5 {micro}g/g among children. Diet factors contributed the most to mercury levels, especially consumption of freshwater fish and livers from game. Other factors, including age, dental amalgams, use of skin-lightening cosmetics, and residence near a gold-mining community, did not contribute significantly to mercury levels. Overall, 12% of the samples contained mercury levels in excess of 10 {micro}g/g, but in some Amerindian communities up to 79% of the children had hair mercury levels that exceeded 10 {micro}g/g. The results of this study indicated that (a) diet played a predominant role in total mercury burden, and (b) in some communities, mercury contamination exceeded safe levels.

Cordier, S.; Mandereau, L. [Inst. National de Sante et de Recherche Medicale, Villejuif (France); Grasmick, C. [Direction Generale de la Sante, Paris (France); Paquier-Passelaigue, M. [Direction Dept. des Affaires Sanitaires et Sociales, Cayenne (France); Weber, J.P. [Centre de Toxicologie du Quebec (Canada); Jouan, M. [Reseau National de Sante Publique, St. Maurice (France)

1998-07-01

33

Tissue mercury concentrations and adrenocortical responses of female big brown bats (Eptesicus fuscus) near a contaminated  

E-print Network

as the adrenocortical responses of insectivorous big brown bats (Eptesicus fuscus) near the Hg-contaminated South River. Keywords Mercury Á Cortisol Á Fur:blood ratio Á Insectivore Á Eptesicus fuscus Introduction Mercury (HgTissue mercury concentrations and adrenocortical responses of female big brown bats (Eptesicus

Hopkins, William A.

34

Mercury Levels in Michigan River Otters, Lutra canadensis  

Microsoft Academic Search

Mercury (Hg) concentrations were examined in kidney and\\/or liver tissues of 43 river otters collected from the upper and northern lower peninsulas of Michigan from 1987–1989. In general, Hg concentrations in Michigan's otters were lower than reported for other localities in the United States but higher than concentrations reported in Michigan fish species. Concentrations were significantly higher in liver tissue

Ramona M. Ropek; Robert K. Neely

1993-01-01

35

Lead, mercury, selenium, and other trace elements in tissues of golden eagles from southwestern Montana, USA.  

PubMed

Lead-based rifle bullets, used in game hunting and recreational shooting, fragment when striking bone and soft tissues. Lead fragments may be ingested by birds scavenging offal piles or nonretrieved carcasses and therefore pose a poisoning risk. We captured and sampled 74 Golden Eagles (Aquila chrysaetos) in southwestern Montana, USA, from 2008 to 2010 to evaluate levels of lead, mercury, selenium, and 13 other trace elements in blood and feathers. Lead was detected in blood of most (97%, n=70) eagles; mean blood level was 0.26 parts per million (ppm). Most eagles (65%) had background levels (<0.2 ppm), 29% had elevated levels (0.2-0.5 ppm), 13% had chronic levels (0.51-1.0 ppm), and 3% had acute levels (>1.0 ppm) in blood. Lead in blood decreased from winter to spring. Resident eagles had higher lead levels than eagles of unknown residency. Mercury was detected in few eagles, whereas selenium was detected in all, but at a low level (0.36 ppm). Other chemical elements in blood were at low or biologically appropriate levels. Lead in feathers (n=29) was correlated with blood lead (P=0.010), as was mercury in blood and feathers (n=48; P=0.003). Concentrations of lead and mercury in feathers were higher in adults than in juveniles and immatures (P<0.016) and both elements tended to increase with age. Selenium in feathers (n=48) appeared stable across plumage classes. Although detection rates of lead in blood of eagles captured in spring increased from 1985-1993 to 2008-2010, mean levels decreased (P<0.023) between periods, as did proportions of eagles exhibiting above background levels (>0.2 ppm; P<0.02). PMID:23307377

Harmata, Alan R; Restani, Marco

2013-01-01

36

Assessment of Mercury in Fish Tissue from Select Lakes of Northeastern Oregon  

EPA Science Inventory

A fish tissue study was conducted in five northeastern Oregon reservoirs to evaluate mercury concentrations in an area where elevated atmospheric mercury deposition had been predicted by a national EPA model, but where tissue data were sparse. The study targeted resident predator...

37

Trace-level mercury removal from surface water  

SciTech Connect

Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water.

Klasson, K.T.; Bostick, D.T.

1998-06-01

38

Chronic effects of low-level mercury and cadmium to goldfish (Carassius Auratus)  

SciTech Connect

During this five and one half year investigation, experiments were performed to determine the effects of nanogram levels of cadmium and mercury on reproductive performance, growth, and tissue residues of goldfish. In addition, embryo-larval bioassays were conducted on these metals to compare the effects of a short-term exposure to a sensitive life-cycle stage (i.e., eggs and larvae) with a sustained exposure to a relatively insensitive life-cycle period (i.e., adult). Reproduction was blocked by the long-term exposure to 0.25 ..mu..g/l mercury and 0.27 ..mu..g/l cadmium. Over the 1972 days, the control fish spawned on eleven occasions, but the experimentals failed to spawn. The metal-induced reproductive impairment continued in the experimentals even after six months in clean water. Growth of the populations exposed to mercury and cadmium was significantly less than that of the control population (P < 0.001). The mercury, cadmium and control populations grew by 229%, 232% and 353%, respectively. Mercury and cadmium continuously accumulated in fish tissues over the entire 1789 days of whole body exposure. Despite exposure to mercury as inorganic metal, organomercury also accumula

Westerman, A.G.

1984-01-01

39

Differentiation of silver-enhanced mercury and gold in tissue sections of rat dorsal root ganglia.  

PubMed

Autometallography was used in conjunction with light and electron microscopy to detect traces of gold and mercury in the dorsal root ganglia of rats treated with sodium aurothiomalate and mercuric chloride. In order to differentiate between gold and mercury in tissue sections, the gold accumulations were removed by potassium cyanide, leaving mercury sulphides/selenides as the only possible catalysts for autometallographic development. With this technique, it is now possible to differentiate between all tissue metals capable of initiating the autometallographic process, i.e. gold, vesicular zinc, and sulphides and selenides of mercury and silver. PMID:8468184

Schiønning, J D; Danscher, G; Christensen, M M; Ernst, E; Møller-Madsen, B

1993-02-01

40

Mercury  

SciTech Connect

Papers are presented on future observations of and missions to Mercury, the photometry and polarimetry of Mercury, the surface composition of Mercury from reflectance spectrophotometry, the Goldstone radar observations of Mercury, the radar observations of Mercury, the stratigraphy and geologic history of Mercury, the geomorphology of impact craters on Mercury, and the cratering record on Mercury and the origin of impacting objects. Consideration is also given to the tectonics of Mercury, the tectonic history of Mercury, Mercury's thermal history and the generation of its magnetic field, the rotational dynamics of Mercury and the state of its core, Mercury's magnetic field and interior, the magnetosphere of Mercury, and the Mercury atmosphere. Other papers are on the present bounds on the bulk composition of Mercury and the implications for planetary formation processes, the building stones of the planets, the origin and composition of Mercury, the formation of Mercury from planetesimals, and theoretical considerations on the strange density of Mercury.

Vilas, F.; Chapman, C.R.; Matthews, M.S.

1988-01-01

41

Tissue distribution of mercury and selenium in minnows, Phoxinus phoxinus  

Microsoft Academic Search

The protective effect of selenium against mercury toxicity has been extensively demonstrated in a number of studies (Burke eta]. 1977; Kasuya 1976). Since mercury uptake is not always diminished by the presence of selenium (Kim eta]. 1977) and neither does selenium enhance the elimination of mercury (Lucu and Skreblin i981; Cuvin and Furness 1988), these findings indicate that the mechanism

Ma. Lourdes A. Cuvin-Aralar; Robert W. Furness

1990-01-01

42

Mercury exposure may suppress baseline corticosterone levels in juvenile birds.  

PubMed

Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury concentrations in down feathers of recently hatched (<3 days) and blood of older (15-37 days) Forster's tern (Sterna forsteri) chicks in San Francisco Bay, California. Baseline fecal corticosterone metabolite concentrations were negatively correlated with mercury concentrations in blood of older chicks (decreasing by 81% across the range of observed mercury concentrations) while accounting for positive correlations between corticosterone concentrations and number of fledgling chicks within the colony and chick age. In recently hatched chicks, baseline fecal corticosterone metabolite concentrations were weakly negatively correlated with mercury concentrations in down feathers (decreasing by 45% across the range of observed mercury concentrations) while accounting for stronger positive correlations between corticosterone concentrations and colony nest abundance and date. These results indicate that chronic mercury exposure may suppress baseline corticosterone concentrations in tern chicks and suggests that a juvenile bird's ability to respond to stress may be reduced via the downregulation of the HPA axis. PMID:22578153

Herring, Garth; Ackerman, Joshua T; Herzog, Mark P

2012-06-01

43

Quantification of total mercury in liver and heart tissue of Harbor Seals (Phoca vitulina) from Alaska USA  

SciTech Connect

This study quantified the Hg levels in the liver (n=98) and heart (n=43) tissues of Harbor Seals (Phoca vitulina) (n=102) harvested from Prince William Sound and Kodiak Island Alaska. Mercury tissue dry weight (dw) concentrations in the liver ranged from 1.7 to 393 ppm dw, and in the heart from 0.19 to 4.99 ppm dw. Results of this study indicate liver and heart tissues' Hg ppm dw concentrations significantly increase with age. Male Harbor Seals bioaccumulated Hg in both their liver and heart tissues at a significantly faster rate than females. The liver Hg bioaccumulation rates between the harvest locations Kodiak Island and Prince William Sound were not found to be significantly different. On adsorption Hg is transported throughout the Harbor Seal's body with the partition coefficient higher for the liver than the heart. No significant differences in the bio-distribution (liver:heart Hg ppm dw ratios (n=38)) values were found with respect to either age, sex or geographic harvest location. In this study the age at which Hg liver and heart bioaccumulation levels become significantly distinct in male and female Harbor Seals were identified through a Tukey's analysis. Of notably concern to human health was a male Harbor Seal's liver tissue harvested from Kodiak Island region. Mercury accumulation in this sample tissue was determined through a Q-test to be an outlier, having far higher Hg concentrarion (liver 392 Hg ppm dw) than the general population sampled. - Highlights: Black-Right-Pointing-Pointer Mercury accumulation in the liver and heart of seals exceed food safety guidelines. Black-Right-Pointing-Pointer Accumulation rate is greater in males than females with age. Black-Right-Pointing-Pointer Liver mercury accumulation is greater than in the heart tissues. Black-Right-Pointing-Pointer Mercury determination by USA EPA Method 7473 using thermal decomposition.

Marino, Kady B. [Department of Chemistry, Roger Williams University, Bristol, RI 02809 (United States)] [Department of Chemistry, Roger Williams University, Bristol, RI 02809 (United States); Hoover-Miller, Anne; Conlon, Suzanne; Prewitt, Jill [Alaska SeaLife Center, City of Seward, AK (United States)] [Alaska SeaLife Center, City of Seward, AK (United States); O'Shea, Stephen K., E-mail: soshea@rwu.edu [Department of Chemistry, Roger Williams University, Bristol, RI 02809 (United States)

2011-11-15

44

Does proximity to coal-fired power plants influence fish tissue mercury?  

E-print Network

Does proximity to coal-fired power plants influence fish tissue mercury? Dana K. Sackett · D. Derek+Business Media, LLC 2010 Abstract Much of the mercury contamination in aquatic biota originates from coal of contaminated fish. In this study, we quantified the relative importance of proximity to coal-fired power plants

45

Mercury concentrations in muscle tissue from sportfish in Lake Mead, Nevada  

Microsoft Academic Search

The aim of this study was to determine the concentrations of mercury present in commonly consumed fish from Lake Mead and to identify if differences exist between the 4 major basins. To date, no formal study using US Environmental Protection Agency (USEPA) approved methodology has been conducted to quantify the amount of mercury present in fish tissue from Lake Mead.

Joanna Kramer; Shawn L. Gerstenberger

2010-01-01

46

MERCURY MAPS: A QUANTITATIVE SPATIAL LINK BETWEEN AIR DEPOSITION AND FISH TISSUE  

EPA Science Inventory

Mercury Maps is a geographic information system (GIS) that relates percent changes in air deposition to percent changes in fish tissue concentration, on a national scale. Mercury Maps documentation derives a simple model, incorporated in the GIS, from recent detailed kinetics-b...

47

Mercury  

Microsoft Academic Search

New findings on the environmental fate of Hg indicate that lakes can be contaminated by long distance transport on mercury vapor in the atmosphere and that higher levels of Me Hg in fish are associated with acidification of lakes and with the creation of hydroelectric reservoirs. Considerable progress has been made in the understanding of the disposition and metabolism of

Thomes W. Clarkson

1989-01-01

48

Egg mercury levels decline with the laying sequence in charadriiformes  

SciTech Connect

Whereas pollutants do not differ in concentration among eggs of one clutch in some bird species, in gulls, terns and grebes several organochlorines show intraclutch variation: Concentrations increase with the laying sequence. Heavy metals, however, are not so intensively studied with respect to intraclutch variation. In contrast to lead and cadmium, mercury is accumulated in great quantities in eggs. Variation in mercury levels between the eggs of one clutch were low compared to interclutch variability in the White-tailed Sea Eagle (Haliaeetus albicilla) and the Peregrine (Falco peregrinus). In gulls, however, intraclutch variation was significant and characterized by higher mercury levels in the first than in subsequently laid eggs, which is the opposite to the trend in organochlorine levels. In this paper, the author reports on investigations of intraclutch variation in mercury levels in three Charadriiform-species, Herring Gull, Common Tern and Oystercatcher (Haematopus ostralegus). The results confirm those previously reported in gulls and point to the importance of the egg in reducing the females' mercury burden. 23 refs, 2 tabs.

Becker, P.H. (Institut fuer Vogelforschung, Wilhelmshaven (Germany))

1992-05-01

49

DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION  

EPA Science Inventory

A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), mill...

50

Distribution and accumulation of mercury in tissues of captive-reared common loon (Gavia immer) chicks  

USGS Publications Warehouse

We determined the distribution and accumulation of Hg in tissues of common loon (Gavia immer) chicks maintained for up to 15 weeks on either a control diet with no added methylmercury chloride (MeHgCl) or one containing either 0.4 or 1.2 ??g Hg (as MeHgCl)/g wet-weight food. Total Hg and MeHg tissue concentrations were strongly positively correlated (r2 > 0.95) with the amount of Hg delivered to individual chicks throughout the course of the experiment. The pattern of differential Hg concentration in internal tissues was consistent within each treatment: Liver > kidney > muscle > carcass > brain. Feather Hg concentrations were consistently higher than those of internal tissues and represented an important route of Hg elimination. Feather mass accounted for 4.3% ?? 0.1% (average ?? standard error) of body mass, yet 27.3% ?? 2.6% of total Hg intake was excreted into feathers. Our calculations indicate that 26.7% ?? 4.9% of ingested Hg was not accounted for and, thus, either was never absorbed or was absorbed and subsequently eliminated in feces. With the additional excretion into feathers, 54% of ingested Hg was excreted. Demethylation was evident in the liver at all treatment levels and in the kidneys of chicks dosed at 1.2 ??g Hg/g. Mercury concentrations were strongly positively correlated (r2 ??? 0.95) among internal tissues and with blood Hg concentration. Mercury concentrations of secondary feathers were moderately correlated (r2 = 0.82-0.93) with internal tissues. We supply regression models that may be used to provide perspective and a useful means of interpreting the variety of measures of Hg exposure reported in the literature. ?? 2007 SETAC.

Kenow, K.P.; Meyer, M.W.; Hines, R.K.; Karasov, W.H.

2007-01-01

51

Distribution and accumulation of mercury in tissues of captive-reared common loon (Gavia immer) chicks.  

PubMed

We determined the distribution and accumulation of Hg in tissues of common loon (Gavia immer) chicks maintained for up to 15 weeks on either a control diet with no added methylmercury chloride (MeHgCl) or one containing either 0.4 or 1.2 microg Hg (as MeHgCl)/g wet-weight food. Total Hg and MeHg tissue concentrations were strongly positively correlated (r2 > 0.95) with the amount of Hg delivered to individual chicks throughout the course of the experiment. The pattern of differential Hg concentration in internal tissues was consistent within each treatment: Liver > kidney > muscle > carcass > brain. Feather Hg concentrations were consistently higher than those of internal tissues and represented an important route of Hg elimination. Feather mass accounted for 4.3% +/- 0.1% (average +/- standard error) of body mass, yet 27.3% +/- 2.6% of total Hg intake was excreted into feathers. Our calculations indicate that 26.7% +/- 4.9% of ingested Hg was not accounted for and, thus, either was never absorbed or was absorbed and subsequently eliminated in feces. With the additional excretion into feathers, 54% of ingested Hg was excreted. Demethylation was evident in the liver at all treatment levels and in the kidneys of chicks dosed at 1.2 microg Hg/g. Mercury concentrations were strongly positively correlated (r2 > or = 0.95) among internal tissues and with blood Hg concentration. Mercury concentrations of secondary feathers were moderately correlated (r2 = 0.82-0.93) with internal tissues. We supply regression models that may be used to provide perspective and a useful means of interpreting the variety of measures of Hg exposure reported in the literature. PMID:17521154

Kenow, Kevin P; Meyer, Michael W; Hines, Randy K; Karasov, William H

2007-05-01

52

Risk, mercury levels, and birds: relating adverse laboratory effects to field biomonitoring.  

PubMed

There is an abundance of field data on levels of mercury in a variety of organisms and there are a number of studies that demonstrate the adverse effects of mercury on laboratory animals, but few studies examine the relationship between the two. Thus it is often difficult to determine the ecological relevance of mercury concentrations found in nature, or to predict the ecosystem consequences of current levels. In this paper we review the levels in tissues that are associated with adverse effects in birds from laboratory studies and compare these with levels found in wild bird populations in the New York Bight to provide a basis for interpreting values in avian populations. We use feathers from fledgling birds which would have been fed on locally obtained food to eliminate the problem of where toxic burdens were acquired by more mobile adult birds. Laboratory studies indicate that in some species mercury levels of 1.5 ppm in eggs and/or 5 to 40 ppm in the feathers of birds are associated with adverse effects, including impaired reproduction. We report egg levels in birds that range as high as 3.8 ppm and feather levels that range as high as 10.3 ppm, although means are much lower. The levels in eggs of some wild birds in the New York Bight are within the range known to lower hatchability, embryo and chick survival, and chick weight, all variables that reduce reproductive success. Species with high egg levels include Forster's tern (Sterna forsteri) and black skimmer (Rynchops niger). Levels in feathers of some young wild birds from the New York Bight are within the range associated with reduced hatchability of eggs, behavioral abnormalities of adults, and infertility. Species with dangerously elevated mercury levels in feathers include great egret (Ardea [=Egretta] alba), snowy egret [Egretta thula), and black skimmers. PMID:9417847

Burger, J; Gochfeld, M

1997-11-01

53

Mercury levels in mink (Mustela vison) and river otter (Lontra canadensis) from northeastern North America.  

PubMed

Aquatic ecosystems have received mercury released from anthropogenic sources. The northeast region of North America is at especially high risk because of local and regional emission sources, prevailing wind patterns, and certain hydrological and biogeochemical features. Here we examine regional variation in total mercury (Hg) in brain, liver, and fur from otter and mink collected across New York, New England, and Nova Scotia. Gender and age are examined as factors potentially affecting Hg tissue levels. In addition, temporal relationships are analyzed for New York as well as correlative relationships for tissues from Maine. Animals were collected from 1982 to 2003, mostly from licensed trappers. Liver was the only tissue from otter that exhibited significant regional variation (New York versus Maine) in Hg concentration. Mercury concentration was significantly related to age but not to gender for otter. All tissues in mink exhibited significant, but inconsistent, regional variation in total Hg concentration, with the highest mean Hg concentration in liver samples from Massachusetts/Connecticut. Female mink had significantly greater Hg concentrations in liver than males. Total Hg concentration in the liver of both otter and mink from New York decreased significantly with time. Correlations among tissues for Hg concentration were stronger for male and female mink and male otter than female otter from Maine. PMID:15931971

Yates, David E; Mayack, David T; Munney, Kenneth; Evers, David C; Major, Andrew; Kaur, Taranjit; Taylor, Robert J

2005-03-01

54

The Relationship between Adirondack Lake pH and Levels of Mercury in Yellow Perch  

Microsoft Academic Search

Levels of total mercury in yellow perch Perca flavescens from Adirondack lakes were studied in relation to characteristics of the lakes to determine why some lakes had fish with higher concentrations of mercury. Almost all mercury in fish is in the form of methylmercury, which can pose significant health hazards to humans who consume such fish. Fish mercury concentrations and

Donald Brown; Alexey Goncharov; Eric Paul; Howard Simonin; David O. Carpenter

2010-01-01

55

Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues  

SciTech Connect

The fate of mercury (Hg) released from dental silver amalgam tooth fillings into human mouth air is uncertain. A previous report about sheep revealed uptake routes and distribution of amalgam Hg among body tissues. The present investigation demonstrates the bodily distribution of amalgam Hg in a monkey whose dentition, diet, feeding regimen, and chewing pattern closely resemble those of humans. When amalgam fillings, which normally contain 50% Hg, are made with a tracer of radioactive {sup 203}Hg and then placed into monkey teeth, the isotope appears in high concentration in various organs and tissues within 4 wk. Whole-body images of the monkey revealed that the highest levels of Hg were located in the kidney, gastrointestinal tract, and jaw. The dental profession's advocacy of silver amalgam as a stable tooth restorative material is not supported by these findings.

Hahn, L.J.; Kloiber, R.; Leininger, R.W.; Vimy, M.J.; Lorscheider, F.L. (Univ. of Calgary, Alberta (Canada))

1990-11-01

56

High levels of mercury in biota of a new Prairie irrigation reservoir with a simplified food web in Southern Alberta, Canada  

Microsoft Academic Search

This study examined mercury levels in northern pike (Esox lucius) from the Twin Valley Reservoir in southern Alberta, 2 years after construction in 2003. The hypothesis was tested that mercury\\u000a concentrations in pike from the reservoir are significantly higher than in pike from the nearby Oldman River. Mercury concentrations\\u000a in muscle tissue (0.37–1.54 ppm) generally exceeded the consumption guideline of 0.5 ppm total

Lars BrinkmannJoseph; Joseph B. Rasmussen

2010-01-01

57

Mercury burden of human fetal and infant tissues  

Microsoft Academic Search

The total mercury concen- trations in the liver (Hg-L), the kid- ney cortex (Hg-K) and the cerebral cortex (Hg-C) of 108 children aged 1 day-5 years, and the Hg-K and Hg-L of 46 fetuses were determined. As far as possible, the mothers were in- terviewed and their dental status was recorded. The results were compared to mercury concentrations in the

G. Drasch; I. Schupp; R. Reinke; G. Roider

1994-01-01

58

Contaminant levels in fish tissue from San Francisco Bay  

SciTech Connect

Edible fish species were collected from thirteen locations throughout San Francisco Bay, during the spring of 1994, for determination of contaminants levels in muscle tissue. Species collected included white croaker, surfperch, leopard and brown smoothhound sharks, striped bass, white sturgeon and halibut Sixty six composite tissue samples were analyzed for the presence of PAHs, PCBs, pesticides, trace elements and dioxin/furans. The US EPA approach to assessing chemical contaminant data for fish tissue consumption was used for identifying the primary chemicals of concern. Six chemicals or chemical groups were found to exceed screening levels established using the US EPA approach. PCBs (as total Aroclors) exceeded the screening level of 3 ppb in all sixty six tissue samples, with the highest concentrations (638 ppb) found near San Francisco`s industrial areas. Mercury was elevated (> 0.14 ppm) in forty of the sixty-six samples with the highest levels (1.26 ppm) occurring in shark muscle tissues. Concentrations of the organochlorine pesticides dieldrin, total chlordanes and total DDTs exceeded screening levels in a number of samples. Dioxin/furans (as TEQs) were elevated (above 0.15 ppt) in 16 of the 19 samples analyzed. Fish with high lipid content (croaker and surfperch) in their muscle tissue generally exhibited higher contaminant levels while fish with low lipid levels (halibut and shark) exhibited lower organic contaminant levels. Tissue samples taken from North Bay stations most often exhibited high levels of chemical contamination. The California Office of Health Hazard Assessment is currently evaluating the results of this study and has issued an interim Health Advisory concerning the human consumption of fish tissue from San Francisco Bay.

Fairey, R. [California Dept. of Fish and Game, Moss Landing, CA (United States). Moss Landing Marine Labs.; Taberski, K. [San Francisco Bay Regional Water Quality Control Board, Oakland, CA (United States)

1995-12-31

59

Distribution and chemical form of mercury in commercial fish tissues.  

PubMed

We analyzed total Hg concentrations in various tissue samples obtained from 7 commercially available fish species. MeHg contents were also estimated for muscle and liver samples by a selective analysis of inorganic Hg. Among the tissues, high Hg accumulations were shown in liver, muscle, heart and spleen throughout all fish species. Carnivorous fish, such as scorpion fish, sea bream and Japanese whiting, tended to show higher Hg accumulations in the muscle, with the highest Hg levels being shown by scorpion fish. Although the liver was expected to show the highest Hg accumulations among tissues throughout all fish species, the highest accumulation in the liver was observed only in scorpion fish. In contrast, the muscle level was significantly higher than the liver in Pacific saury and Japanese whiting. MeHg accumulated in fish is considered to show a sustained increase throughout the life of the fish, due to its long biological half-life. In fact, in the present study, muscle Hg levels in Japanese whiting, Japanese flying fish, and halfbeak showed good correlations with body weights. However, such correlations were not clear in scorpion fish, sea bream, Jack mackerel and Pacific saury. Selective analyses of inorganic Hg levels revealed that most of the Hg (> 95%) in fish muscle existed as MeHg, while the rates of MeHg contents in the liver varied from 56% in scorpion fish to 84% in Jack mackerel. As a result, fish muscle showed the highest MeHg accumulations in all fish species examined. These results suggest that reliable information on total Hg contents in fish muscle might be sufficient to avoid the risk of MeHg exposure caused by eating fish, even when one consumes other tissues such as fish liver. PMID:22863865

Watanabe, Naoko; Tayama, Misato; Inouye, Minoru; Yasutake, Akira

2012-01-01

60

MERCURY, LEAD, ARSENIC, AND CADMIUM IN BIOLOGICAL TISSUE. THE NEED FOR ADEQUATE STANDARD REFERENCE MATERIALS  

EPA Science Inventory

The present situation of standard reference materials consisting of plant and animal tissues is examined. A brief literature review presents a cross-section of published data on the incorporation of mercury, lead, arsenic and cadmium into plant and animal tissues. It points out t...

61

[Correlation of fat content and dioxins, total mercury and methyl mercury levels in tuna].  

PubMed

In this study, we analyzed the concentrations of mercury and dioxins in tuna with various fat contents (akami; the leaner meat, Chutoro; the belly area of the tuna along the side of the fish between the akami and the otoro. Otoro; the fattiest portion of the tuna) in wild and farmed bluefin tuna and farmed southern bluefin tuna. In the three kinds of tuna, average dioxins concentrations in Akami, chutoro and otoro were 1.7, 4.7 and 9.6 pg TEQ/g, respectively. The dioxins concentration in all three regions of tuna was in direct proportion to the fat content. In the farmed bluefin tuna, the dioxins concentration was almost the same as that of the wild tuna, but differed from that of the farmed southern bluefin tuna. Average total mercury concentration based on wet weight in akami was 0.42 µg/g, being higher than the values of 0.36 µg/g of chutoro and 0.31 µg/g of otoro, and in inverse proportion to the fat content. In all three regions, the total mercury concentration of the wild bluefin tuna was equal to that of the farmed tuna. The total mercury concentration in the latter was two to three times higher than that of the farmed southern bluefin tuna. If the Japanese intake is one fin of tuna (80 g) a day, the daily intake levels of dioxins and methyl mercury can be estimated as 0.48-37 pg TEQ/kg bw and 0.21-0.90 µg/kg bw, respectively. PMID:21071911

Kawakami, Hiroyuki; Amakura, Yoshiaki; Tsutsumi, Tomoaki; Sasaki, Kumiko; Iketsu, Ayumi; Inasaki, Mizue; Kubota, Emi; Toyoda, Masatake

2010-01-01

62

TISSUE MERCURY CONCENTRATIONS AND POTENTIAL NEUROGPATHOLOGICAL CHANGES IN COMMON LOONS (GAVIA IMMER)  

EPA Science Inventory

Common loons (Gavia immer) in New England are exposed to high levels of mercury through their diet. Mercury bioaccumulates through the food chain as methylmercury, a neurotoxin which has been shown in controlled feeding studies to have detrimental effects on the health and behavi...

63

Mercury  

NSDL National Science Digital Library

This site offers information on the planet Mercury. Some topics include: the atmosphere, surface, and interior of Mercury, missions to Mercury, recent discoveries, and myths and culture related to Mercury. There are also numerous pictures and additional websites to find more information.

2005-06-07

64

Mercury  

MedlinePLUS

Mercury is an element that is found in air, water and soil. It has several forms. Metallic mercury is a shiny, silver-white, odorless liquid. If ... with other elements to form powders or crystals. Mercury is in many products. Metallic mercury is used ...

65

Distribution of mercury in the soft tissues of the Blue Tilapia Oreochromis aureus (Steindachner) after acute exposure to mercury (II) chloride  

SciTech Connect

Mercury has no known biological functions in the animal body and is described as an ultratrace element. Consequently, there is no well defined regulatory mechanism present in the animal body and it tends to accumulate readily if available in an animal's environment. Sources of mercury include the chloroalkali industry, the manufacture of electrical equipment, paint, fungicides and dentistry. The use of mercury in the gold mining industry has caused extensive pollution in the Amazon Basin. Whether fish take up organic or inorganic mercury, most of it accumulates in the tissues in the organic form. Most cases of mercury poisoning arising from fish consumption are due to methylmercury because mercury entering the aquatic system rapidly becomes methylated. Minamata disease in humans was first reported in 1956 due to consumption of contaminated fish and shellfish from Minamata Bay. Therefore it is important to monitor the mercury content of fish which are caught or farmed for human consumption. Since many commercial animal feeds contain a fish meal component, monitoring is important from the aspect of contamination of farm animals intended for human consumption. Oreochromis aureus (Steindachner) is a species of tilapia often cultured in ponds and also in cages in North and Latin America. Therefore, it is a suitable model to use for studying the effects of mercury exposure on the distribution of mercury in different tissues of fish. Distribution is important, because different cultures consume different fish organs, not just the muscle portion alone. The tissues which have a high content of mercury will be most dangerous from a toxicological viewpoint. Removal of the tissues known to contain the highest concentrations of mercury would reduce the mercury content of fish meal. Since fish are often species-specific in their responses to heavy metals, it is important to study a species which is actually farmed and cultured as a food fish. 20 refs., 2 tabs.

Allen, P.

1994-11-01

66

Total mercury distribution in different tissues of frigate tuna (Auxis thazard thazard) from the Atlantic Coastal Waters of Ghana, Gulf of Guinea.  

PubMed

Total mercury concentrations in different tissues of frigate tuna fish (Auxis thazard thazard) was determined by the cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer. A mixture of HNO3, HClO4 and H(2)SO(4) was used for complete oxidation of organic tissue. The concentration of mercury obtained was in the order Gills < Stomach < Gonads < Intestine < Heart < Duodenum < Liver < Muscle. The concentration of total mercury detected in the edible muscle tissue of the tuna fish tested ranged from 0.044 to 0.201 microg g(-1) (mean = 0.108 microg g(-1)) wet weight. These levels are all within the maximum allowed/recommended level in fish (0.5 mug g(-1) wet weight) set by the Food and Agriculture Organisation/World Health Organisation (FAO/WHO) and are therefore unlikely to constitute any significant mercury exposure to the general population because of consumption of tuna fish. The results of the study suggest a relatively clean marine environment that has not been significantly impacted by mercury contamination probably due to minimal industrial activity in the region. PMID:17286183

Voegborlo, R B; Adimado, A A; Ephraim, J H

2007-09-01

67

Lead and mercury levels in raccoons from Macon County, Alabama  

SciTech Connect

Heavy metal contamination in the environment has become a major concern of the scientific community. The ubiquitous present of heavy metals such as lead, mercury, and cadmium in wildlife animals has been reported. Although the understanding of the full significance of these metals is incomplete, it is known that some species contain concentrations of metals proportional to the levels present in their environments. Thus, wild animals can be used as biological indicators of environmental concentrations of metals. The behavior, omnivorous feeding habits, and adaptability of raccoons (Procyon lotor) qualify this animal as a useful indicator of environmental pollution. The purpose of this paper was to report some preliminary observations on lead and mercury levels in raccoons from Macon County, Alabama, a potential indicator species for wildlife. 19 refs., 3 tabs.

Khan, A.T.; Thompson, S.J. [Tuskegee Univ., AL (United States); Mieike, H.W. [Xavier Univ. of Louisiana, New Orleans, LA (United States)

1995-06-01

68

Glutathione level after long-term occupational elemental mercury exposure  

SciTech Connect

Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg{sup o}) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg{sup o}-not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from 'mercury-free works'. Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p<0.05) than in the controls. No differences in mean GPx activity among the three groups were found, whereas the mean GR activity was significantly higher (p<0.05) in miners than in retired miners. The mean concentrations of GSH (mmol/g Hb) in miners (13.03{+-}3.71) were significantly higher (p<0.05) than in the control group (11.68{+-}2.66). No differences in mean total GSH, GSSG levels, and GSH/GSSG ratio between miners and controls were found. A positive correlation between GSSG and present U-Hg excretion (r=0.41, p=0.001) in the whole group of ex-mercury miners was observed. The significantly lower GSH level (p<0.05) determined in the group of retired miners (9.64{+-}1.45) seems to be age-related (r=-0.39, p=0.001). Thus, the moderate but significantly increased GSH level, GR and CAT activity in erythrocytes in the subgroup of miners observed in the period after exposure to Hg{sup o} could be an inductive and additive response to maintain the balance between GSH and antioxidative enzymes in interaction with the Hg body burden accumulated during remote occupational exposure, which does not represent a severely increased oxidative stress.

Kobal, Alfred Bogomir [University Medical Centre Ljubljana, Institute of Clinical Chemistry and Biochemistry, Njegoseva 4, SI-1525 Ljubljana (Slovenia)], E-mail: abkobal@volja.net; Prezelj, Marija [University Medical Centre Ljubljana, Institute of Clinical Chemistry and Biochemistry, Njegoseva 4, SI-1525 Ljubljana (Slovenia); Horvat, Milena [Department of Environmental Sciences, Jozef Stefan Institute, Ljubljana (Slovenia); Krsnik, Mladen [University Medical Centre Ljubljana, Institute of Clinical Chemistry and Biochemistry, Njegoseva 4, SI-1525 Ljubljana (Slovenia); Gibicar, Darija [Department of Environmental Sciences, Jozef Stefan Institute, Ljubljana (Slovenia); Osredkar, Josko [University Medical Centre Ljubljana, Institute of Clinical Chemistry and Biochemistry, Njegoseva 4, SI-1525 Ljubljana (Slovenia)

2008-05-15

69

Inverse relationships between selenium and mercury in tissues of young walleye (Stizosedion vitreum) from Canadian boreal lakes  

E-print Network

Inverse relationships between selenium and mercury in tissues of young walleye (Stizosedion vitreum 22 November 2009 Available online 16 December 2009 Keywords: Selenium Methylmercury Mercury Fish selenium (Se) were determined in muscle, liver and brain tissues of young-of-the-year walleye (Stizosedion

Belzile, Nelson

70

Mercury  

MedlinePLUS

... Releases and Spills Fish Consumption Advice Consumer Products Mercury News September 2014 – EPA has proposed effluent limitation ... 2014 press release News Archive Minimata Convention on Mercury EPA web page on the Minimata Convention United ...

71

Mercury  

NSDL National Science Digital Library

This lithograph shows mosaic images of Mercury, captured by the Mariner 10 spacecraft. The images are accompanied by a brief description and history, some statistical facts, and a list of significant dates in the exploration of Mercury.

72

Mercury Concentration in the Tissue of Terrestrial Arthropods from the Central California Coast  

NASA Astrophysics Data System (ADS)

The primary goal of this project was to obtain a baseline understanding and investigate the concentration of mercury (Hg) in the tissue of arthropods in coastal California. This region receives significant input of fog which may contain enhanced levels of Hg. Currently there is a lack of data on Hg concentration in the tissue of arthropods (Insecta, Malacostraca, and Arachnida). The sample collection sites were Elkhorn Slough Estuarine Reserve in Moss Landing, and the University of California Santa Cruz (UCSC) campus. Samples collected between February and March, 2012 had total Hg (HgT) concentrations in dry weight that ranged from 27 - 39 ng/g in the Jerusalem cricket (Orthoptera Stenopelmatidae); 80 - 110 ng/g in the camel cricket (Orthoptera Rhaphidophoridae); 21 - 219 ng/g in the ground beetle (Coleoptera Carabidae); 100 - 228 ng/g in the pill bug (Isopoda Armadillidiidae); and 285 - 423 ng/g in the wolf spider (Araneae Lycosidae). Monomethyl mercury (MMHg) concentrations in dry weight were determine to be 4.3 -28.2 ng/g for the ground beetle; 45.5 - 87.8 ng/g for the pill bug, and 252.3 - 293.7 ng/g for the wolf spider. Samples collected in July, 2012 had HgT concentrations in dry weight that ranged from 110 - 168 ng/g in the camel cricket; 337 - 562 ng/g in the ground beetle; 25 - 227 ng/g in the pill bug; and 228 - 501 ng/g in the wolf spider. The preliminary data revealed an 18% increase in the concentration of HgT for wolf spiders, and a 146% increase for ground beetles in the summer when compared to those concentrations measured in the spring. It is hypothesized that coastal fog may be a contributor to this increase of Hg concentration in coastal California arthropods.

Ortiz, C.; Weiss-Penzias, P. S.; Flegal, A. R.

2012-12-01

73

Risk, Mercury Levels, and Birds: Relating Adverse Laboratory Effects to Field Biomonitoring  

Microsoft Academic Search

There is an abundance of field data on levels of mercury in a variety of organisms and there are a number of studies that demonstrate the adverse effects of mercury on laboratory animals, but few studies examine the relationship between the two. Thus it is often difficult to determine the ecological relevance of mercury concentrations found in nature, or to

Joanna Burger; Michael Gochfeld

1997-01-01

74

Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues  

Microsoft Academic Search

The fate of mercury (Hg) released from dental silver amalgam tooth fillings into human mouth air is uncertain. A previous report about sheep revealed uptake routes and distribution of amalgam Hg among body tissues. The present investigation demonstrates the bodily distribution of amalgam Hg in a monkey whose dentition, diet, feeding regimen, and chewing pattern closely resemble those of humans.

LESZEK J. HAHN; REINHARD KLOIBER; RONALD W. LEININGER; M. J. Vimy; FRITZ L. LORSCHEIDER

1990-01-01

75

A PREDICTIVE MODEL OF MERCURY FISH TISSUE CONCENTRATIONS FOR THE SOUTHEAST UNITED STATES  

EPA Science Inventory

The potential adverse effects of chemical contaminants in fish is an ongoing EPA concern that is directly related to Clean Water Act responsibilities to ensure that waters of the United States are fishable and swimmable. Mercury is a fish tissue contaminant that can bioaccumulat...

76

Relationship between dietary mercury intake and blood mercury level in Korea.  

PubMed

This study was performed to evaluate the effect of dietary factors for mercury exposure by comparing with blood mercury concentration. Study population consisted of 1,866 adults (839 men and 1,027 women) in randomly-selected 30 districts in southeast Korea. Dietary mercury intake was calculated from food frequency questionnaire (FFQ) on seafood items and 24 hr recall record. Blood mercury concentration was measured with atomic absorption spectrometry. Mean age of the subjects was 43.5 ± 14.6 yr. The FFQ showed that mercury-laden fish (tuna, shark) and frequently-eating fish (squid, belt fish, mackerel) were important in mercury intake from fish species. The recall record suggested that fish and shellfish was a highest group (63.1%) of mercury intake and had a wide distribution in the food groups. In comparison with the blood mercury concentration, age group, sex, household income, education, drinking status and coastal area were statistically significant (P < 0.001). In multiple regression analysis, coefficient from the FFQ (? = 0.003) had greater effect on the blood mercury than the recall record (? = 0.002), but the effect was restricted (adjusted R(2) = 0.234). Further studies with more precise estimation of dietary mercury intake were required to evaluate the risk for mercury exposure by foods and assure risk communication with heavily-exposed group. PMID:24550642

You, Chang-Hun; Kim, Byoung-Gwon; Kim, Yu-Mi; Lee, Sang-Ah; Kim, Rock-Bum; Seo, Jeong-Wook; Hong, Young-Seoub

2014-02-01

77

STATE FISH SURVEY FINDS MERCURY LEVELS DOWN By Alex Breitler  

E-print Network

as mercury. Some mercury occurs naturally, and some has persisted in the environment since the Gold Rush days, when it was used to extract gold from rocks. Some is also deposited into our waterways from the air

78

Bioaccumulation potential of dietary arsenic, cadmium, lead, mercury, and selenium in organs and tissues of rainbow trout (Oncorhyncus mykiss) as a function of fish growth.  

PubMed

The distribution and potential bioaccumulation of dietary arsenic, cadmium, lead, mercury, and selenium in organs and tissues of rainbow trout (Oncorhyncus mykiss Walbaum, 1792), a major aquaculture species, was studied in relation to fish growth over a period of >3 years. Fish were reared under normal farming conditions, that is, fed a standard fish food and exposed to negligible levels of waterborne trace elements. The age-related variations in the content of each trace element in gills, kidney, liver, muscle, and skin were studied through nonparametric regression analysis. A buildup of all elements in all tissues and organs was observed, but due to dilution with growth, the concentrations did not increase, except in a few cases such as cadmium and mercury in liver and kidney. In muscle tissue, the concentrations of mercury, lead, and selenium did not alter significantly with growth, whereas cadmium increased but remained at exceedingly low levels. The concentration of arsenic in muscle tissue peaked at 14 months and then decreased in adult specimens. Arsenic speciation by high-performance liquid chromatography--inductively coupled plasma mass spectrometry revealed that arsenic in muscle was almost exclusively present in the form of nontoxic arsenobetaine. Application of a mercury mass balance model gave predicted concentrations in agreement with measured ones and showed that in farmed rainbow trout the ratio of mercury concentrations in feed and in fish is about 1:1. Therefore, rainbow trout does not approach the limits established for human consumption even when reared with feed at the maximum permitted levels. These findings highlight the low bioaccumulation potential of toxic trace elements such as cadmium, lead, and mercury in rainbow trout following dietary exposure. On the other hand, selenium concentrations in muscle (about 0.2 microg g (-1) of fresh weight) show that rainbow trout may be a good source of this essential element. PMID:18327907

Ciardullo, Silvia; Aureli, Federica; Coni, Ettore; Guandalini, Emilio; Iosi, Francesca; Raggi, Andrea; Rufo, Giovanna; Cubadda, Francesco

2008-04-01

79

Response of fish tissue mercury in a freshwater lake to local, regional, and global changes in mercury emissions.  

PubMed

A suite of mechanistic atmospheric and mercury (Hg) cycling and bioaccumulation models is applied to simulate atmospheric Hg deposition and Hg concentrations in the water column and in fish in a Hg-impaired freshwater lake located in the northeastern United States that receives its Hg loading primarily through deposition. Two future-year scenarios evaluate the long-term response of fish tissue Hg concentrations to reductions in local and nationwide coal-fired electric-generating utility and other Hg emissions and an increase or decrease in global (non-US) Hg emissions. Results indicate that fish tissue Hg concentrations in this ecosystem could require approximately 3 yr to 8 yr to begin to respond to declines in US emissions and deposition with a fish Hg reduction proportional to deposition reduction requiring over 50 yr. Furthermore, recovery could potentially be partially or completely offset by growth in non-US Hg emissions. PMID:24771700

Vijayaraghavan, Krish; Levin, Leonard; Parker, Lynsey; Yarwood, Greg; Streets, David

2014-06-01

80

New Jersey mercury regulations  

SciTech Connect

Mercury, or quicksilver, and its major ore cinnabar (HgS) have been known for thousands of years. Health effects from mercury such as dementia were known as early as the late 19th century ({open_quotes}mad as a hatter{close_quotes}). In the 1960`s and 1970`s, reported levels of mercury in tuna reawakened public awareness of mercury pollution. In the 1970`s, major epidemics of acute mercury poisoning were reported in Japan and Iraq. These incidents highlighted the extreme health risks, such as kidney damage, birth defects, and death, associated with severe mercury poisoning. Fetuses and young children are particularly vulnerable since mercury poisoning can damage growing neural tissues. Recently, the perception of mercury as a dangerous pollutant has been on the rise. Advisories warning the public to avoid or reduce the consumption of freshwater fish caught in specific waterbodies due to mercury contamination have been issued in numerous states. The discovery of mercury in {open_quotes}pristine{close_quotes} lakes in the United States, Canada, and Scandinavia, remote from industry and any known mercury sources, has focused attention on atmospheric emissions of mercury as potential significant sources of mercury.

Elias, D.F.; Corbin, W.E. [RTP Environmental Associates, Inc., Green Brook, NJ (United States)

1996-12-31

81

Mercury and selenium concentrations in muscle tissue of different species of predatory freshwater fish and correlation between these elements.  

PubMed

Concentrations of total mercury and selenium were determined in 49 and 42 muscle tissue samples, respectively, of six species of predatory freshwater fish, dace (Leuciscus leuciscus), pike perch (Sander lucioperca), pike (Esox lucius), European catfish (Silurus glanis), rainbow trout (Oncorhynchus mykiss) and asp (Aspius aspius). Muscle selenium concentration did not correlate with the corresponding total mercury concentration (R(2) < 0.198) in all examined predatory fish species. There was an inverse correlation between the ratio Se/Hg content and the total mercury content in the muscle tissues of dace, pike perch, pike, European catfish and asp. The muscle tissue of rainbow trout exhibits a linear correlation between the ratio Se/Hg content and the total mercury content. The total mercury concentration of all examined samples did not exceed the hygienic limit for Hg for predatory fish. PMID:24779785

Strapá?, Imrich; Sokol, Jozef; Žatko, Daniel; Baranová, Mária

2012-01-01

82

Species- and tissue-specific mercury bioaccumulation in five fish species from Laizhou Bay in the Bohai Sea of China  

NASA Astrophysics Data System (ADS)

Mercury (Hg) concentrations in the tissues (muscle, stomach, liver, gills, skin, and gonads) of five fish species (mullet Liza ha em atocheil us, flathead fish Platycephalus indicus, sea bass Lateolabrax japonic u s, mackerel Scomberomorus niphonius and silver pomfret Pampus argenteus) collected from Laizhou Bay in the Bohai Sea of China were investigated. The results indicate that Hg bioaccumulation in the five fish was tissue-specific, with the highest levels in the muscle and liver, followed by the stomach and gonads. The lowest levels were found in the gills and skin. Fish at higher trophic levels (flathead fish and sea bass) exhibited higher Hg concentrations than consumers at lower trophic levels. Mercury bioaccumulation tended to be positively correlated with fish length in mullet, silver pomfret, mackerel, and flathead fish, but was negatively correlated with fish length in sea bass. The Hg concentrations in the muscles of all fish species in Laizhou Bay were within the permissible limits of food safety set by national and international criteria. However, the suggesting maximum consumption of sea bass is 263 g per week for human health.

Liu, Jinhu; Cao, Liang; Huang, Wei; Dou, Shuozeng

2013-05-01

83

Temporal and geographic trends in mercury concentrations in muscle tissue in five species of Hudson River, USA, fish.  

PubMed

We analyzed a New York (USA) state database of mercury concentrations in muscle tissue for five species of fish (striped bass, yellow perch, largemouth bass, smallmouth bass, and carp) over a range of locations in the Hudson River (USA) between 1970 and 2004. We used regression models to discern temporal and geographic change in the fish while controlling for a positive correlation between mercury concentration and body mass. Mercury concentrations significantly increased in fish from New York Harbor waters to the mid-Hudson River. Striped bass and yellow perch showed a shallower increase in mercury concentration with river mile than did carp, largemouth bass, and smallmouth bass. Mercury concentrations declined over the 34-year period. These results imply that a geographically restricted source of mercury may be spread throughout the watershed by toxin-laden dispersing species. The increase of mercury toward the north may relate to a point source in the mid-Hudson River, or it may indicate mercury released from the Adirondack watershed. The decline of mercury over three decades corresponds to a reduction of various inputs in the region. The temporal and geographic pattern of mercury in sediments corresponds to the geographic trend of mercury in fish. PMID:18266478

Levinton, Jeffrey S; Pochron, Sharon T

2008-08-01

84

Assessment of nonlethal methods for predicting muscle tissue mercury concentrations in coastal marine fishes.  

PubMed

Caudal fin clips and dorsolateral scales were analyzed as a potential nonlethal approach for predicting muscle tissue mercury (Hg) concentrations in marine fish. Target fish were collected from the Narragansett Bay (Rhode Island, USA) and included black sea bass Centropristis striata [n = 54, 14-55 cm total length (TL)], bluefish Pomatomus saltatrix (n = 113, 31-73 cm TL), striped bass Morone saxatilis (n = 40, 34-102 cm TL), summer flounder Paralichthys dentatus (n = 64, 18-55 cm TL), and tautog Tautoga onitis (n = 102, 27-61 cm TL). For all fish species, Hg concentrations were greatest in muscle tissue [mean muscle Hg = 0.47-1.18 mg/kg dry weight (dw)] followed by fin clips (0.03-0.09 mg/kg dw) and scales (0.01-0.07 mg/kg dw). The coefficient of determination (R (2)) derived from power regressions of intraspecies muscle Hg against fin and scale Hg ranged between 0.35 and 0.78 (mean R (2) = 0.57) and 0.14-0.37 (mean R (2) = 0.30), respectively. The inclusion of fish body size interaction effects in the regression models improved the predictive ability of fins (R (2) = 0.63-0.80; mean = 0.71) and scales (R (2) = 0.33-0.71; mean = 0.53). According to the high level of uncertainty within the regression models (R (2) values) and confidence interval widths, scale analysis was deemed an ineffective tool for estimating muscle tissue Hg concentrations in the target species. In contrast, the examination of fin clips as predictors of muscle Hg had value as a cursory screening tool; however, this method should not be the foundation for developing human consumption advisories. It is also noteworthy that the efficacy of these nonlethal techniques was highly variable across fishes and likely depends on species-specific life-history characteristics. PMID:23929385

Piraino, Maria N; Taylor, David L

2013-11-01

85

Assessment of nonlethal methods for predicting muscle tissue mercury concentrations in coastal marine fishes  

PubMed Central

Caudal fin clips and dorsolateral scales were analyzed in this study as a potential nonlethal approach for predicting muscle tissue mercury (Hg) concentrations in marine fishes. Target fishes were collected from the Narragansett Bay (RI, USA), and included black sea bass Centropristis striata (n = 54, 14–55 cm total length, TL), bluefish Pomatomus saltatrix (n = 113, 31–73 cm TL), striped bass Morone saxatilis (n = 40, 34–102 cm TL), summer flounder Paralichthys dentatus (n = 64, 18–55 cm TL), and tautog Tautoga onitis (n = 102, 27–61 cm TL). For all fish species, Hg concentrations were greatest in muscle tissue (mean muscle Hg = 0.47–1.18 mg/kg dry weight), followed by fin clips (0.03–0.09 mg/kg dry weight) and scales (0.01–0.07 mg/kg dry weight). The coefficient of determination (R2) derived from power regressions of intra-species muscle Hg against fin and scale Hg ranged between 0.35–0.78 (mean R2 = 0.57) and 0.14–0.37 (mean R2 = 0.30), respectively. The inclusion of fish body size interaction effects in the regression models improved the predictive ability of fins (R2 = 0.63–0.80; mean = 0.71) and scales (R2 = 0.33–0.71; mean = 0.53). According to the high level of uncertainty within the regression models (R2 values) and confidence interval widths, scale analysis was deemed an ineffective tool for estimating muscle tissue Hg concentrations in the target species. In contrast, the examination of fin clips as predictors of muscle Hg had value as a cursory screening tool, but this method should not be the foundation for developing human consumption advisories. It is also noteworthy that the efficacy of these nonlethal techniques was highly variable across fishes, and likely depends on species-specific life history characteristics. PMID:23929385

Piraino, Maria N.; Taylor, David L.

2013-01-01

86

Mercury concentrations in seabird tissues from Machias Seal Island, New Brunswick, Canada.  

PubMed

Mercury is a pervasive environmental contaminant, the anthropogenic portion of which is increasing globally, and in northeastern North America in particular. Seabirds frequently are used as indicators of the marine environment, including mercury contamination. We analysed paired samples for total mercury (Hg) concentrations in feathers and blood from adult and chick, albumen, and lipid-free yolk of seven seabirds breeding on Machias Seal Island, New Brunswick, Canada - Arctic Tern (Sterna paradisaea), Atlantic Puffin (Fratercula arctica), Common Eider (Somateria mollissima), Common Murre (Uria aalge), Common Tern (Sterna hirundo), Leach's Storm-petrel (Oceanodroma leucorhoa), and Razorbill (Alca torda). We also used stable-isotope ratios of carbon (delta(13)C), and nitrogen (delta(15)N) to evaluate the relationship between carbon source and trophic position and mercury. We found high Hg concentrations across tissue types in Leach's Storm-petrels, and Razorbills, with lower concentrations in other species, the lowest being in Common Eiders. Storm-petrels prey on mesopelagic fish that accumulate mercury, and Razorbills feed on larger, older fish that bioaccumulate heavy metals. Biomagnification of Hg, or the increase in Hg concentration with trophic position as measured by delta(15)N, was significant and greater in albumen than other tissues, whereas in other tissues, delta(15)N explained little of the overall variation in Hg concentration. Hg concentrations in egg components are higher on Machias Seal Island than other sites globally and in the Gulf of Maine region, but only for some species. Further detailed investigations are required to determine the cause of this trend. PMID:19419752

Bond, Alexander L; Diamond, Antony W

2009-07-01

87

Effects of low dietary levels of methyl mercury on mallard reproduction  

USGS Publications Warehouse

Mallard ducks were fed a control diet or a diet containing 0.5 ppm or 3 ppm mercury (as methylmercury dicyandiamide). Health of adults and reproductive success were studied. The dietary level of 3 ppm mercury had harmful effects on reproduction, although it did not appear to affect the health of the adults during the 12 months of dosage. Ducks that were fed the diet containing 0.5 ppm mercury reproduced as well as controls, and ducklings from parents fed 0.5 ppm mercury grew faster in the first week of life than did controls....The greatest harm to reproduction associated with the diet containing 3 ppm mercury was an increase in duckling mortality, but reduced egg laying and increased embryonic mortality also occurred....During the peak of egg laying, eggs laid by controls tended to be heavier than eggs laid by ducks fed either level of mercury; however, there seemed to be no eggshell thinning associated with mercury treatment. Levels of mercury reached about 1 ppm in eggs from ducks fed a dietary dosage of 0.5 ppm mercury and between 6 and 9 ppm in the eggs from ducks fed 3 ppm mercury.

Heinz, G.

1974-01-01

88

Comparative baseline levels of mercury, Hsp 70 and Hsp 60 in subsistence fish from the Yukon-Kuskokwim delta region of Alaska.  

PubMed

In subsistence fish; northern pike (Esox lucius), burbot (Lota lota), whitefish (Coregonus nelsoni), grayling (Thymallus arcticus) and sheefish (Stenodus lencichthys), we determined the Hsp 60 and Hsp 70 levels in 31 samples from adult fish gills. A dot-blot analysis using antibodies to either Hsp 70 or Hsp 60 showed the average Hsp 70 concentration was 9.1 microg/mg protein, while the average Hsp 60 concentration was 147.4 microg/mg protein. Mercury levels in muscle tissue in these fish averaged 0.382 ppm. Using a subset of samples (n = 24), we determined that the major component in the muscle of Alaskan subsistence fish was methyl mercury. No correlation was observed between Hsp 60 or Hsp 70 expression in gill tissue and mercury concentrations in muscle tissue. Hsp 60 and Hsp 70 protein levels in the gills were correlated. PMID:10622434

Duffy, L K; Scofield, E; Rodgers, T; Patton, M; Bowyer, R T

1999-10-01

89

The influence of depth on mercury levels in pelagic fishes and their prey  

PubMed Central

Mercury distribution in the oceans is controlled by complex biogeochemical cycles, resulting in retention of trace amounts of this metal in plants and animals. Inter- and intra-specific variations in mercury levels of predatory pelagic fish have been previously linked to size, age, trophic position, physical and chemical environmental parameters, and location of capture; however, considerable variation remains unexplained. In this paper, we focus on differences in ecology, depth of occurrence, and total mercury levels in 9 species of commercially important pelagic fish (Thunnus obesus, T. albacares, Katsuwonus pelamis, Xiphias gladius, Lampris guttatus, Coryphaena hippurus, Taractichthys steindachneri, Tetrapturus audax, and Lepidocybium flavobrunneum) and in numerous representatives (fishes, squids, and crustaceans) of their lower trophic level prey sampled from the central North Pacific Ocean. Results indicate that total mercury levels of predatory pelagic fishes and their prey increase with median depth of occurrence in the water column and mimic concentrations of dissolved organic mercury in seawater. Stomach content analysis results from this study and others indicate a greater occurrence of higher-mercury containing deeper-water prey organisms in the diets of the deeper-ranging predators, X. gladius, T. obesus, and L. guttatus. While present in trace amounts, dissolved organic mercury increases with depth in the water column suggesting that the mesopelagic habitat is a major entry point for mercury into marine food webs. These data suggest that a major determinant of mercury levels in oceanic predators is their depth of forage. PMID:19666614

Choy, C. Anela; Popp, Brian N.; Kaneko, J. John; Drazen, Jeffrey C.

2009-01-01

90

The influence of depth on mercury levels in pelagic fishes and their prey.  

PubMed

Mercury distribution in the oceans is controlled by complex biogeochemical cycles, resulting in retention of trace amounts of this metal in plants and animals. Inter- and intra-specific variations in mercury levels of predatory pelagic fish have been previously linked to size, age, trophic position, physical and chemical environmental parameters, and location of capture; however, considerable variation remains unexplained. In this paper, we focus on differences in ecology, depth of occurrence, and total mercury levels in 9 species of commercially important pelagic fish (Thunnus obesus, T. albacares, Katsuwonus pelamis, Xiphias gladius, Lampris guttatus, Coryphaena hippurus, Taractichthys steindachneri, Tetrapturus audax, and Lepidocybium flavobrunneum) and in numerous representatives (fishes, squids, and crustaceans) of their lower trophic level prey sampled from the central North Pacific Ocean. Results indicate that total mercury levels of predatory pelagic fishes and their prey increase with median depth of occurrence in the water column and mimic concentrations of dissolved organic mercury in seawater. Stomach content analysis results from this study and others indicate a greater occurrence of higher-mercury containing deeper-water prey organisms in the diets of the deeper-ranging predators, X. gladius, T. obesus, and L. guttatus. While present in trace amounts, dissolved organic mercury increases with depth in the water column suggesting that the mesopelagic habitat is a major entry point for mercury into marine food webs. These data suggest that a major determinant of mercury levels in oceanic predators is their depth of forage. PMID:19666614

Choy, C Anela; Popp, Brian N; Kaneko, J John; Drazen, Jeffrey C

2009-08-18

91

Selenium modulates mercury uptake and distribution in rice (Oryza sativa L.), in correlation with mercury species and exposure level.  

PubMed

Rice cultured in Hg- and/or Se-contaminated fields is an important food source of human Hg/Se intake. There are elevated Hg and Se levels in the soil of the Wanshan District, Guizhou Province. Here we attempted to explore how a Hg antagonist, Se, modulates the absorption and accumulation of inorganic mercury (IHg) and methylmercury (MeHg) in rice. The effects of Se on the content and transportation of Hg in hydroponic and soil cultured rice plants were examined. The results show that IHg mainly accumulated in the rice roots, but some also accumulated in the rice grain. In comparison to IHg, MeHg can be concentrated in the rice grain, and the proportion of MeHg in the rice grain may account for above 40% of the total Hg. Se can protect against Hg phytotoxicity in rice and inhibit IHg accumulation in rice tissues, but was not remarkable for MeHg at a low dosage exposure level in this study. These discrepancies imply mechanistic differences between IHg and MeHg absorption and accumulation in rice. This study illustrates that Se plays an important role in modulating Hg uptake, transportation and accumulation in rice. Therefore, Se is considered to be a naturally existing element that effectively reduces Hg accumulation in rice, which may have significant implications for food safety. PMID:25142173

Zhao, Jiating; Li, Yufeng; Li, Yunyun; Gao, Yuxi; Li, Bai; Hu, Yi; Zhao, Yuliang; Chai, Zhifang

2014-10-01

92

Concentrations of mercury in tissues of striped dolphins suggest decline of pollution in Mediterranean open waters.  

PubMed

The Mediterranean is a semi-enclosed sea subject to high mercury (Hg) pollution from both natural and anthropogenic sources. With the objective of discerning temporal changes in marine Hg pollution in the oceanic waters of the northwestern Mediterranean Sea, we analysed liver and kidney from striped dolphins (Stenella coeruleoalba) collected during 2007-2009 and compared them with previous results from a similar sample from 1990-1993. The effect of body length and sex on tissue Hg concentrations was investigated to ensure an unbiased comparison between the periods. The Hg concentrations did not show significant sex-related differences in any tissue or period but were correlated positively with body length. Using body length as a covariate, Hg concentrations in liver and kidney were higher in 1990-1993 than in 2007-2009. This result suggests that measures to reduce emissions in Western European countries have been effective in reducing mercury pollution in Mediterranean open waters. PMID:24461428

Borrell, A; Aguilar, A; Tornero, V; Drago, M

2014-07-01

93

Mercury levels and potential risk from subsistence foods from the Aleutians  

Microsoft Academic Search

Considerable attention has been devoted to contaminants (mainly PCBs and mercury) in subsistence foods (particularly fish) from various parts of the world. However, relatively little attention has been devoted to examining mercury levels in a full range of subsistence foods from a particular region. While managers and scientists compute risk based on site-specific data on contaminant levels and consumption rates,

Joanna Burger; Michael Gochfeld; Christian Jeitner; Sean Burke; Tim Stamm; Ronald Snigaroff; Dan Snigaroff; Robert Patrick; Jim Weston

2007-01-01

94

A Prospective Clinical Study on Blood Mercury Levels Following Endodontic Root-end Surgery with Amalgam  

PubMed Central

Introduction The purpose of this clinical study was to compare the blood mercury levels before and after endodontic surgery using amalgam as a root-end filling material. Materials and Methods Fourteen patients requiring periradicular surgery participated in this prospective clinical study. A zinc-free amalgam was employed as root-end filling material. Blood samples were collected at three intervals: immediately before, immediately after and one week postoperatively. Mercury content of the blood was determined using gold amalgamation cold-vapor atomic absorption spectrometry. Obtained data were analyzed using analysis of variance for repeated measures and paired t-test. Results The mean (SD) of blood mercury levels was 2.20 (0.24) ng/mL immediately before surgery, 2.24 (0.28) ng/mL immediately after surgery and 2.44 (0.17) ng/mL one week after the periradicular surgery. The blood mercury level one week post-operative was significantly higher than both blood mercury levels immediately before (P<0.001) and immediately after (P=0.005) the surgery. Conclusion Placement of an amalgam retroseal during endodontic surgery can increase blood mercury levels after one week. The mercury levels however, are still lower than the toxic mercury levels. We suggest using more suitable and biocompatible root-end filling materials. PMID:23922566

Saatchi, Masoud; Shadmehr, Elham; Talebi, Seyed Morteza; Nazeri, Mohsen

2013-01-01

95

Mercury  

MedlinePLUS

... enters the air from mining ore deposits, burning coal and waste, and from manufacturing plants. It enters ... to cause cancer? There are inadequate human cancer data available for all forms of mercury. Mercuric chloride ...

96

Total and Methyl Mercury Distribution in Water, Sediment, and Fish tissue in New England Streams  

NASA Astrophysics Data System (ADS)

Conditions that are conducive to the methylation of mercury are of particular concern because methyl mercury (MeHg) is the most toxic mercury species and is rapidly bioaccumulated and biomagnified in wildlife and man. The New England Coastal Basins study unit, as part of the U.S. Geological Survey's National Water Quality Assessment program, has evaluated relations between concentrations of total mercury (HgT) and MeHg in stream water and bed sediment, and HgT in fish tissue at sites with a variety of watershed characteristics. Fifty-five stream sites from Rhode Island to Maine were sampled for water and bed sediment during 1998 - 2000. A subset of 27 sites was sampled for fish tissue. Sediment, water, and fish tissue samples were collected during summer low flow conditions within a week of each other to show patterns of MeHg accumulation and partitioning relative to site and watershed conditions. Concentrations of HgT in water and bed sediment ranged from 1 to 13 nanograms per liter (ng/L) and from 7 to 3,100 nanograms per gram (ng/g) dry weight, respectively. Concentrations of MeHg in water and sediment ranged from 0.04 to 1.8 ng/L and from 1 to 38 ng/g dry weight, respectively, and were positively correlated with concentrations of organic carbon. Methylation efficiency, as estimated by MeHg/HgT, ranged from 0.003 to 0.282 for sediment and water samples, with a median value of 0.071. Methylation efficiency was highest at sampling sites with low urbanization and high organic carbon concentrations. HgT concentrations in fish tissue (mixed sunfish species) ranged from 42 to 349 ng/g wet weight and were positively correlated with concentrations of MeHg in water and bed sediment. A positive relation was not observed between HgT concentrations in fish tissue and HgT concentrations in water and bed sediment. These preliminary results indicate a high potential for mercury bioaccumulation in aquatic organisms in New England streams.

Chalmers, A. T.; Krabbenhoft, D. P.

2001-05-01

97

Mercury correlations among six tissues for four waterbird species breeding in San Francisco Bay, California, USA.  

PubMed

Despite a large body of research concerning mercury (Hg) in birds, no single tissue has been used consistently to assess Hg exposure, and this has hampered comparisons across studies. We evaluated the relationships of Hg concentrations among tissues in four species of waterbirds (American avocets [Recurvirostra americana], black-necked stilts [Himantopus mexicanus], Caspian terns [Hydroprogne caspia; formerly Sterna caspia], and Forster's terns [Sterna forsteri]) and across three life stages (prebreeding adults, breeding adults, and chicks) in San Francisco Bay, California, USA. Across species and life stages, Hg concentrations (least square mean +/- standard error) were highest in head feathers (6.45 +/- 0.31 microg/g dry wt) and breast feathers (5.76 +/- 0.28 microg/g dry wt), followed by kidney (4.54 +/- 0.22 microg/g dry wt), liver (4.43 +/- 0.21 microg/g dry wt), blood (3.10 +/- 0.15 microg/g dry wt), and muscle (1.67 +/- 0.08 microg/g dry wt). Relative Hg distribution among tissues, however, differed by species and life stage. Mercury concentrations were highly correlated among internal tissues (r2 > or = 0.89). Conversely, the relationships between Hg in feathers and internal tissues were substantially weaker (r2 < or = 0.42). Regression slopes sometimes differed among species and life stages, indicating that care must be used when predicting Hg concentrations in one tissue based on those in another. However, we found good agreement between predictions made using a general tissue-prediction equation and more specific equations developed for each species and life stage. Finally, our results suggest that blood is an excellent, nonlethal predictor of Hg concentrations in internal tissues but that feathers are relatively poor indicators of Hg concentrations in internal tissues. PMID:18444697

Eagles-Smith, Collin A; Ackerman, Joshua T; Adelsbach, Terrence L; Takekawa, John Y; Miles, A Keith; Keister, Robin A

2008-10-01

98

Chapter A5. Section 6.4.B. Low-Level Mercury  

USGS Publications Warehouse

Collecting and processing water samples for analysis of mercury at a low (subnanogram per liter) level requires use of ultratrace-level techniques for equipment cleaning, sample collection, and sample processing. Established techniques and associated quality-assurance (QA) procedures for the collection and processing of water samples for trace-element analysis at the part-per-billion level (NFM 3-5) are not adequate for low-level mercury samples. Modifications to the part-per-billion procedures are necessary to minimize contamination of samples at a typical ambient mercury concentration, which commonly is at the subnanogram-per-liter level.

Lewis, Michael Edward; Brigham, Mark E.

2004-01-01

99

Glutathione enzyme and selenoprotein polymorphisms associate with mercury biomarker levels in Michigan dental professionals  

SciTech Connect

Mercury is a potent toxicant of concern to both the general public and occupationally exposed workers (e.g., dentists). Recent studies suggest that several genes mediating the toxicokinetics of mercury are polymorphic in humans and may influence inter-individual variability in mercury accumulation. This work hypothesizes that polymorphisms in key glutathione synthesizing enzyme, glutathione s-transferase, and selenoprotein genes underlie inter-individual differences in mercury body burden as assessed by analytical mercury measurement in urine and hair, biomarkers of elemental mercury and methylmercury, respectively. Urine and hair samples were collected from a population of dental professionals (n = 515), and total mercury content was measured. Average urine (1.06 {+-} 1.24 ug/L) and hair mercury levels (0.49 {+-} 0.63 ug/g) were similar to national U.S. population averages. Taqman assays were used to genotype DNA from buccal swab samples at 15 polymorphic sites in genes implicated in mercury metabolism. Linear regression modeling assessed the ability of polymorphisms to modify the relationship between mercury biomarker levels and exposure sources (e.g., amalgams, fish consumption). Five polymorphisms were significantly associated with urine mercury levels (GSTT1 deletion), hair mercury levels (GSTP1-105, GSTP1-114, GSS 5 Prime ), or both (SEPP1 3 Prime UTR). Overall, this study suggests that polymorphisms in selenoproteins and glutathione-related genes may influence elimination of mercury in the urine and hair or mercury retention following exposures to elemental mercury (via dental amalgams) and methylmercury (via fish consumption). -- Highlights: Black-Right-Pointing-Pointer We explore the influence of 15 polymorphisms on urine and hair Hg levels. Black-Right-Pointing-Pointer Urine and hair Hg levels in dental professionals were similar to the US population. Black-Right-Pointing-Pointer GSTT1 and SEPP1 polymorphisms associated with urine Hg levels. Black-Right-Pointing-Pointer Accumulation of Hg in hair following exposure from fish was modified by genotype. Black-Right-Pointing-Pointer GSTP1, GSS, and SEPP1 polymorphisms influenced Hg accumulation in hair.

Goodrich, Jaclyn M.; Wang, Yi [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)] [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Gillespie, Brenda [Department of Biostatistics, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)] [Department of Biostatistics, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Werner, Robert [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States) [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Department of Physical Medicine and Rehabilitation, University of Michigan, 325 E. Eisenhower Parkway Suite 100, Ann Arbor, MI 48108 (United States); Franzblau, Alfred [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)] [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Basu, Niladri, E-mail: niladri@umich.edu [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)] [Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)

2011-12-15

100

Human hair mercury levels in the Wanshan mercury mining area, Guizhou Province, China  

Microsoft Academic Search

The total mercury (T-Hg) and methyl mercury (Me-Hg) concentrations in the hair were measured to evaluate mercury (Hg) exposure\\u000a for the residents in Da-shui-xi Village (DSX) and Xia-chang-xi Village (XCX) in the Wanshan Hg mining area, Guizhou Province,\\u000a Southwestern China. The mean concentrations in the hair of DSX residents were 5.5 ± 2.7 ?g\\/g and 1.9 ± 0.9 ?g\\/g for T-Hg and\\u000a Me-Hg, respectively. The concentrations

Ping Li; Xinbin Feng; Guangle Qiu; Lihai Shang; Guanghui Li

2009-01-01

101

Mercury Levels in Locally Manufactured Mexican Skin-Lightening Creams  

PubMed Central

Mercury is considered one of the most toxic elements for plants and animals. Nevertheless, in the Middle East, Asia and Latin America, whitening creams containing mercury are being manufactured and purchased, despite their obvious health risks. Due to the mass distribution of these products, this can be considered a global public health issue. In Mexico, these products are widely available in pharmacies, beauty aid and health stores. They are used for their skin lightening effects. The aim of this work was to analyze the mercury content in some cosmetic whitening creams using the cold vapor technique coupled with atomic absorption spectrometry (CV-AAS). A total of 16 skin-lightening creams from the local market were investigated. No warning information was noted on the packaging. In 10 of the samples, no mercury was detected. The mercury content in six of the samples varied between 878 and 36,000 ppm, despite the fact that the U.S. Food and Drug Administration (FDA) has determined that the limit for mercury in creams should be less than 1 ppm. Skin creams containing mercury are still available and commonly used in Mexico and many developing countries, and their contents are poorly controlled. PMID:21776243

Peregrino, Claudia P.; Moreno, Myriam V.; Miranda, Silvia V.; Rubio, Alma D.; Leal, Luz O.

2011-01-01

102

Mercury levels in Great Lakes herring gull eggs, 1972--1992  

SciTech Connect

Since 1971, the herring gull (Larus argentatus) has been used as a sentinel species for monitoring the levels of persistent contaminants in the Great Lakes ecosystem. In this study, 21 herring gull colonies in the Great Lakes and connecting channels were sampled for years 1972--1976, 1981--1983, 1985 and 1992. For each year, 10 eggs (usually) were collected from each colony site and analyzed for total mercury (ppm, wet weight). Results indicated that eggs from Lake Ontario displayed the highest mercury levels, mean = 0.28 (s.d. = 0.08) to 0.73 (0.23). Lake Erie typically displayed the lowest egg mercury levels, 0.18 (0.08) to 0.24 (0.11). Overall, mercury levels ranged from 0.12 (0.02) in 1985 to 0.88 (0.23) in 1982 for Channel-Shelter Island (Lake Huron) and Pigeon Island (Lake Ontario), respectively. Generally, all colony sites showed peak mercury levels in 1982. A significant decline in egg mercury levels was observed in six colony sites between 1972 and 1992 and in three colony sites between 1981 and 1992. The mean herring gull egg mercury levels observed in the early and mid 1970s and in 1982 for some colony sites were within the range found which potentially reduces hatchability in other fish-eating bird species.

Weseloh, D.V.; Koster, M.D.; Ryckman, D.P.; Struger, J. [Canadian Wildlife Service, Burlington, Ontario (Canada). Canada Centre for Inland Waters

1995-12-31

103

Mercury and selenium interaction: A review  

Microsoft Academic Search

This paper reviews studies on mercury and selenium interaction. It includes the effects of selenium on mercury toxicity on the organism, organ\\/tissue, and subcellular levels. The paper also touches on possible mechanisms for the protective action of selenium against mercury toxicity and deals briefly with the synergism between the two elements. 71 references.

M. L. Cuvin-Aralar; R. W. Furness

1991-01-01

104

Relations between total mercury, methylmercury and selenium in five tissues of Sepia officinalis captured in the south Portuguese coast.  

PubMed

Mercury, methylmercury and selenium were determined in digestive gland, branchial hearts, mantle, kidney and gills of Sepia officinalis from two areas of the south Portuguese coast. To the best of our knowledge these are the first data on Hg, MeHg and Se in branchial hearts, kidney and gills of cuttlefish. Digestive gland, branchial hearts and kidney presented higher levels of Hg and Se than mantle and gills. Methylmercury was significantly higher in digestive gland, branchial hearts and mantle. The enhanced levels of Hg in digestive gland and branchial heart reinforce the elevated storage capacity of these two tissues. The percentage of MeHg varied from 6.1% in gills to 92% in mantle. Linear and positive MeHg-Hg relations were obtained for the five tissues, being the better relation and higher slope observed for mantle, followed by branchial hearts, digestive gland, kidney and gills. The Se:Hg molar ratios showed a surplus of Se in all tissues. Calculations based on the equimolarity of Se:Hg point that 95-99% of Se are not linked to Hg (Se free). The negligible quantity of Se associated with Hg suggests that the mechanism of MeHg demethylation was not triggered in none of the tissues, presumably because the threshold for MeHg toxicity was not achieved. PMID:24582035

Raimundo, Joana; Pereira, Patrícia; Vale, Carlos; Canário, João; Gaspar, Miguel

2014-08-01

105

Mercury  

NSDL National Science Digital Library

This NASA (National Aeronautics and Space Administration) planet profile provides data and images of the planet Mercury. These data include planet size, distance from the Sun, rotation and revolution times, temperature, atmospheric composition, density, and albedo. Images of the planet include general surface features such as crater basins, the Caloris Basin, and other images taken by the Mariner 10 spacecraft.

106

Mercury  

Microsoft Academic Search

Mercury is the least-explored planet except for Pluto. The Mariner 10 mission yielded much information about the planet, but raised new questions. Groundbased observations of the polar craters and atmosphere have also raised new questions. The Messenger mission will address many of these, but in order to maximize the return from this mission, a program of laboratory, observational, and theoretic

A. E. Potter; R. M. Killen; B. Hapke

2002-01-01

107

Mercury levels in a 21-year-old black-crowned night heron (Nycticorax nycticorax)  

Microsoft Academic Search

Mercury levels in a 21-year-old black crowned night heron were measured. Concentrations were: breast muscle (0.9 ppm), liver (3.1 ppm), brain (0.5ppm), and primary wing feathers (17.9 ppm). These levels were not substantially different from those found in much younger birds. These data imply that either the kind had been feeding in an area with low levels of mercury contaminations

Hoffman

1976-01-01

108

MERCURY LEVELS IN HAWAIIAN PREDATORY PEI-AGIC FISHES AND THEIR PREY ASA FUNCTION OF DEPTH AND ECOLOGY  

E-print Network

MERCURY LEVELS IN HAWAIIAN PREDATORY PEI-AGIC FISHES AND THEIR PREY ASA FUNCTION OF DEPTH Gregory F,. P.av:.zza N{argaretA. N.,Icl\\{anus #12;ABSTRACT Mercury is drstributedthroughout the Earth in plants and animals. Inter- and intra-specific variations in mercury levels of predatory pelagic fish have

Luther, Douglas S.

109

Health effects in the Flemish population in relation to low levels of mercury exposure: from organ to transcriptome level.  

PubMed

Due to possible health risks, quantification of mercury accumulation in humans was included in the Flemish biomonitoring programmes FLEHS I (2002-2006) and FLEHS II (2007-2011). The general objective of FLEHS I was to assess regional exposure levels in order to link possible differences in these internal exposure levels to different types of local environmental pressure. Therefore, Hg and MMHg (methylmercury) were only measured in pooled blood samples per region and per age class. In FLEHS II, mercury concentrations were measured in hair of each participant. About 200 adolescents and 250 mothers (reference group) and two times 200 adolescents (2 hotspots) were screened. The main objectives of the FLEHS II study were: (1) to determine reference levels of mercury in hair for Flanders; (2) to assess relations between mercury exposure and possible sources like fish consumption; (3) to assess dose-effect relations between mercury exposure and health effect markers. The results showed that mercury concentrations in the Flemish population were rather low compared to other studies. Mercury levels in the Flemish populations were strongly related to the age of the participants and consumption of fish. Significant negative associations were observed between mercury in hair and asthma, having received breast feeding as a newborn, age at menarche in girls, allergy for animals and free testosterone levels. Significant correlations were also observed between mercury in hair and genes JAK2, ARID4A, Hist1HA4L (boys) and HLAdrb5, PIAS2, MANN1B1, GIT and ABCA1 (girls). PMID:23920476

Croes, Kim; De Coster, Sam; De Galan, Sandra; Morrens, Bert; Loots, Ilse; Van de Mieroop, Els; Nelen, Vera; Sioen, Isabelle; Bruckers, Liesbeth; Nawrot, Tim; Colles, Ann; Den Hond, Elly; Schoeters, Greet; van Larebeke, Nicolas; Baeyens, Willy; Gao, Yue

2014-03-01

110

Elevated mercury levels in a wintering population of common eiders (Somateria mollissima) in the northeastern United States.  

PubMed

In North America and Europe, sea ducks are important indicators of ecological health and inshore marine pollution. To explore spatial variation in mercury accumulation in common eiders in the northeastern United States, we compared concentrations of total mercury in common eider blood at several New England locations between 1998 and 2013. Eider food items (mollusks) were collected and analyzed to determine if mercury concentrations in eider blood were indicative of local mercury bioavailability. Eiders from Plum Island Sound, MA had a significantly higher mean blood mercury concentration (0.83 ?g/g) than those in other locations. Mean mercury levels in this population were also nearly three times higher than any blood mercury concentrations reported for common eiders in published literature. We observed consistent patterns in eider blood mercury and blue mussel mercury concentrations between sites, suggesting a tentative predictive quality between the two species. PMID:25066457

Meattey, Dustin E; Savoy, Lucas; Beuth, Josh; Pau, Nancy; O'Brien, Kathleen; Osenkowski, Jason; Regan, Kevin; Lasorsa, Brenda; Johnson, Ian

2014-09-15

111

Temporal characterization of mercury accumulation at different trophic levels and implications for metal biomagnification along a coastal food web.  

PubMed

The main goal of this study was to assess temporal mercury variations along an estuarine food web to evaluate the mercury contamination level of the system and the risks that humans are exposed to, due to mercury biomagnification. The highest mercury concentrations in the sediments and primary producers (macrophytes) were observed during winter sampling. Instead, the highest mercury concentrations in the water, suspended particulate matter as well as in the zooplanktonic and suprabenthic communities were observed during summer sampling. Evidences of mercury biomagnification along the food web were corroborated by the positive biomagnification factors, particularly for omnivorous macrobenthic species. Comparing the mercury levels at distinct components with several environmental quality criteria it suggests that sediments, water and edible species (e.g., bivalve Scrobicularia plana and the crustacean Carcinus maenas) presented higher mercury levels than the values accepted by legislation which represent a matter of concern for the environment and human health. PMID:25172612

Cardoso, P G; Pereira, E; Duarte, A C; Azeiteiro, U M

2014-10-15

112

Mercury  

NASA Technical Reports Server (NTRS)

Prior to the flight of the Mariner 10 spacecraft, Mercury was the least investigated and most poorly known terrestrial planet (Kuiper 1970, Devine 1972). Observational difficulties caused by its proximity to the Sun as viewed from Earth caused the planet to remain a small, vague disk exhibiting little surface contrast or details, an object for which only three major facts were known: 1. its bulk density is similar to that of Venus and Earth, much greater than that of Mars and the Moon; 2. its surface reflects electromagnetic radiation at all wavelengths in the same manner as the Moon (taking into account differences in their solar distances); and 3. its rotation period is in 2/3 resonance with its orbital period. Images obtained during the flyby by Mariner 10 on 29 March 1974 (and the two subsequent flybys on 21 September 1974 and 16 March 1975) revealed Mercury's surface in detail equivalent to that available for the Moon during the early 1960's from Earth-based telescopic views. Additionally, however, information was obtained on the planet's mass and size, atmospheric composition and density, charged-particle environment, and infrared thermal radiation from the surface, and most significantly of all, the existence of a planetary magnetic field that is probably intrinsic to Mercury was established. In the following, this new information is summarized together with results from theoretical studies and ground-based observations. In the quantum jumps of knowledge that have been characteristic of "space-age" exploration, the previously obscure body of Mercury has suddenly come into sharp focus. It is very likely a differentiated body, probably contains a large Earth-like iron-rich core, and displays a surface remarkably similar to that of the Moon, which suggests a similar evolutionary history.

Gault, D. E.; Burns, J. A.; Cassen, P.; Strom, R. G.

1977-01-01

113

40 CFR Table 5 to Subpart IIIii of... - Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans  

Code of Federal Regulations, 2012 CFR

...2011-07-01 true Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans...Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt....

2012-07-01

114

40 CFR Table 5 to Subpart IIIii of... - Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans...Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt....

2011-07-01

115

40 CFR Table 5 to Subpart IIIii of... - Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans...Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt....

2013-07-01

116

Mercury Distribution in Blood, Tissues, and Feathers of Double-Crested Cormorant Nestlings from Arid-Lands Reservoirs in South Central New Mexico  

Microsoft Academic Search

.   Eggs, blood, liver, muscle, and feathers were analyzed for concentrations of total mercury in double-crested cormorant (Phalacrocorax auritus) nestlings from two reservoirs in south central New Mexico. Total mercury concentrations among eggs, tissues, and feathers\\u000a were not significantly correlated. Concentrations of total mercury averaged 0.40 ?g\\/g in liver and 0.18 ?g\\/g in muscle tissues\\u000a in both populations of nestlings.

C. A. Caldwell; M. A. Arnold; W. R. Gould

1999-01-01

117

Influence of illegal gold mining on mercury levels in fish of North Sulawesi's Minahasa Peninsula, (Indonesia)  

Microsoft Academic Search

North Sulawesi's Minahasa Peninsula currently is experiencing intense illegal gold mining activity. It has been estimated that 200 t of mercury are used annually in Indonesia in the recovery of gold from the illegal mines. To date no study has assessed the environmental impact of this illegal activity on the nearby aquatic biota. To address this concern, we compared tissue

Joice L. Kambey; A. p. Farrell; L. i. Bendell-young

2001-01-01

118

LEVEL AND EXTENT OF MERCURY CONTAMINATION IN OREGON, USA, LOTIC FISH  

EPA Science Inventory

Because of growing concern with widespread mercury contamination of fish tissue, we sampled 154 streams and rivers throughout Oregon using a probability design. To maximize the sample size we took samples of small and large fish, where possible, from wadeable streams and boatable...

119

Impact of Wildfire on Levels of Mercury in Forested Watershed Systems - Voyageurs National Park, Minnesota  

USGS Publications Warehouse

Atmospheric deposition of mercury to remote lakes in mid-continental and eastern North America has increased approximately threefold since the mid-1800s (Swain and others, 1992; Fitzgerald and others, 1998; Engstrom and others, 2007). As a result, concerns for human and wildlife health related to mercury contamination have become widespread. Despite an apparent recent decline in atmospheric deposition of mercury in many areas of the Upper Midwest (Engstrom and Swain, 1997; Engstrom and others, 2007), lakes in which fish contain levels of mercury deemed unacceptable for human consumption and possibly unacceptable for fish-consuming wildlife are being detected with increasing frequency. In northern Minnesota, Voyageurs National Park (VNP) (fig. 1) protects a series of southern boreal lakes and wetlands situated on bedrock of the Precambrian Canadian Shield. Mercury contamination has become a significant resource issue within VNP as high concentrations of mercury in loons, bald eagle eaglets, grebes, northern pike, and other species of wildlife and fish have been found. The two most mercury-contaminated lakes in Minnesota, measured as methylmercury in northern pike (Esox lucius), are in VNP. Recent multidisciplinary U.S. Geological Survey (USGS) research demonstrated that the bulk of the mercury in lake waters, soils, and fish in VNP results from atmospheric deposition (Wiener and others, 2006). The study by Wiener and others (2006) showed that the spatial distribution of mercury in watershed soils, lake waters, and age-1 yellow perch (Perca flavescens) within the Park was highly variable. The majority of factors correlated for this earlier study suggested that mercury concentrations in lake waters and age-1 yellow perch reflected the influence of ecosystem processes that affected within-lake microbial production and abundance of methylmercury (Wiener and others, 2006), while the distribution of mercury in watershed soils seemed to be partially dependent on forest disturbance, especially the historic forest fire pattern (Woodruff and Cannon, 2002). Forest fire has an essential role in the forest ecosystems of VNP (Heinselman, 1996). Because resource and land managers need to integrate both natural wildfire and prescribed fire in management plans, the potential influence of fire on an element as sensitive to the environment as mercury becomes a critical part of their decisionmaking. A number of recent studies have shown that while fire does have a significant impact on mercury at the landscape level, the observed effects of fire on aquatic environments are highly variable and unpredictable (Caldwell and others, 2000; Garcia and Carrigan, 2000; Kelly and others, 2006; Nelson and others, 2007). Caldwell and others (2000) described an increase in methylmercury in reservoir sediments resulting from mobilization and transport of charred vegetative matter following a fire in New Mexico. Krabbenhoft and Fink (2000) attributed increases in total mercury concentrations in young-of-the-year fish in the Florida Everglades to release of mercury resulting from peat oxidation following fires. A fivefold increase in whole-body mercury accumulation by rainbow trout (Oncorhynchus mykiss) following a fire in Alberta, Canada, apparently resulted from increased nutrient concentrations that enhanced productivity and restructured the food web of a lake within the fire's burn footprint (Kelly and others, 2006). For this study, we determined the short-term effects of forest fire on mercury concentrations in terrestrial and aquatic environments in VNP by comparing and contrasting mercury concentrations in forest soils, lake waters, and age-1 yellow perch for a burned watershed and an adjacent lake, with similar samples from watersheds and lakes with no fire activity (control watersheds and lakes). The concentration of total mercury in whole, 1-year-old yellow perch serves as a good biological indicator for monitoring trends in methylmercury conce

Woodruff, Laurel G.; Sandheinrich, Mark B.; Brigham, Mark E.; Cannon, William F.

2009-01-01

120

Mercury in Canadian prairie ducks  

Microsoft Academic Search

Tissues of 190 ducks, shot on the Canadian prairie during the hunting seasons of 1969 and 1970, were analyzed for mercury residues. Residue levels of over 0.5 ppm were found only in breast muscle of common mergansers (Mergus merganser). Livers contained, on the average, 2.9 times as much mercury as breast muscles. Primary feathers contained, on the average, 12 times

K. Vermeer; F. A. J. Armstrong

1972-01-01

121

Tissue-specific bioaccumulation and oxidative stress responses in juvenile Japanese flounder ( Paralichthys olivaceus) exposed to mercury  

NASA Astrophysics Data System (ADS)

To understand mercury (Hg) toxicity in marine fish, we measured Hg accumulation in juvenile Japanese flounder ( Paralichthys olivaceus) and assessed the effects on growth and antioxidant responses. After Hg exposure (control, 5, 40, and 160 ?g/L Hg) for 28 d, fish growth was significantly reduced. The accumulation of Hg in fish was dose-dependent and tissue-specific, with the maximum accumulation in kidney and liver, followed by gills, bone, and muscle. Different antioxidants responded differently to Hg exposure to cope with the induction of lipid peroxidation (LPO), which was also tissue-specific and dosedependent. As Hg concentration increased, superoxide dismutase (SOD) and catalase (CAT) activities increased significantly, whereas glutathione S -transferase (GST) activity and glutathione (GSH) levels decreased significantly in the gills. SOD and glutathione peroxidase (GPx) activities and the GSH level increased significantly in the liver. SOD activity and GSH levels increased significantly, but CAT activity decreased significantly with an increase in Hg concentration in the kidney. LPO was induced significantly by elevated Hg in the gills and kidney but was least affected in the liver. Therefore, oxidative stress biomarkers in gills were more sensitive than those in the liver and kidney to Hg exposure. Thus, the gills have potential as bioindicators for evaluating Hg toxicity in juvenile flounder.

Huang, Wei; Cao, Liang; Ye, Zhenjiang; Lin, Longshan; Chen, Quanzhen; Dou, Shuozeng

2012-07-01

122

Mercury levels of Nelson's and saltmarsh sparrows at wintering grounds in Virginia, USA.  

PubMed

Nelson's and saltmarsh sparrows (Ammodramus nelsoni and A. caudacutus) have recently been recognized as separate species, and because of their limited distributions and the susceptibility of their wetland habitats to climate change, these two new species are of conservation concern. Both species are known to bioaccumulate mercury at breeding sites in New England, USA where their ranges overlap, with the saltmarsh sparrow reported to have twice the concentration of blood total mercury. In this study we sampled both species on their shared wintering grounds, and documented that mercury exposure is lower than that reported for the breeding range, with saltmarsh sparrow blood mercury 2.6 times higher than in Nelson's sparrow. Feather mercury, which is incorporated on the breeding grounds, confirmed that saltmarsh sparrows had incorporated 2.3 times more mercury than Nelson's sparrows during the previous breeding season. A comparison of stable isotopes of nitrogen and carbon suggests that the higher exposure of saltmarsh sparrows may be not due to feeding at a higher trophic level, as previously hypothesized, but rather could be related to a difference in the carbon source at the base of each species' food chain. This study, along with recently published data from both species on additional breeding and wintering grounds, provides a more complete picture of relative mercury exposure. Saltmarsh sparrows are exposed to mercury levels that warrant concern, with the highest exposure being during the breeding season. Areas set aside for the long-term conservation of this species should be carefully assessed for mercury bioaccumulation. PMID:21698442

Cristol, Daniel A; Smith, Fletcher M; Varian-Ramos, Claire W; Watts, Bryan D

2011-11-01

123

Blood Mercury Level and Its Determinants among Dental Practitioners in Hamadan, Iran  

PubMed Central

Objective: Exposure to mercury can occur in occupational and environmental settings. During clinical work with dental amalgam, the dental personnel are exposed to both metallic mercury and mercury vapor. The aim of the present study was to investigate blood mercury level (BML) and its determinants among dentists practicing in Hamadan city, Iran. Materials and Methods: This cross sectional study was done on all dental practitioners of Hamadan (n=43). Dentists were asked to complete a questionnaire, and then 5 ml blood samples were obtained from them. After preparation, mercury concentration of each sample was measured by cold vapor atomic absorption device. Pearson correlation test and regression models served for statistical analysis. Results: The mean blood concentration of mercury was 6.3 ?g/l (SD=1.31 range 4.15–8.93). BML was positively associated with age, years in practice, working hours per day, number of amalgam restorations per day, number of amalgam removal per week, sea food consumption, working years in present office, using amalgam powder, using diamond bur for amalgam removal, dry sterilization of amalgam contaminated instruments, and deficient air ventilation. Conclusion: BML of dentists in Hamadan was higher than standards. Working hours and number of amalgam restorations per day were significantly correlated with blood mercury. PMID:21998776

Kasraei, Sh.; Mortazavi, H.; Vahedi, M.; Bakianian Vaziri, P.; Assary, MJ.

2010-01-01

124

The relationship between Adirondack lake pH and levels of mercury in yellow perch.  

PubMed

Levels of total mercury in yellow perch Perca flavescens from Adirondack lakes were studied in relation to characteristics of the lakes to determine why some lakes had fish with higher concentrations of mercury. Almost all mercury in fish is in the form of methylmercury, which can pose significant health hazards to humans who consume such fish. Fish mercury concentrations and water chemistry data were analyzed from eight Adirondack lakes. Four lakes (Halfmoon Lake, Sand Pond, Rock Pond, and Upper Sister Lake) had pH values of less than 5.0. Four other lakes (Lake Adirondack, Kings Flow, Harris Lake, and Lake Kushaqua) had pH values of more than 7.0. The acidic lakes also had high levels of aluminum and low acid-neutralizing capacity relative to the neutral lakes. Yellow perch (n = 100) from the acidic lakes had significantly higher levels of mercury than did those (n = 102) from the neutral lakes (P < 0.001), and the total mercury concentration increased with both length and weight of the fish. We conclude that the pH of the lake water is a major factor in determining the concentration of methylmercury in yellow perch. PMID:21413513

Brown, Donald; Goncharov, Alexey; Paul, Eric; Simonin, Howard; Carpenter, David O

2010-12-01

125

Tuna fish diet influences cat behavior. [Elevated levels of selenium and mercury in commercial tuna fish cat food  

SciTech Connect

When observed in their home cages, cats fed commercial tuna fish cat food were less active, vocalized less, and spent more time on the floor and more time eating than cats fed commercial beef cat food. There were no differences in response to human handling between the two groups. There were no differences in learning ability on a two-choice point maze or in reversal learning in the same maze between beef- and tuna-fed cats. The behavior of the groups differed in a 15-min open field test only in the number of toys contacted. Cats fed the tuna had elevated tissue levels of mercury and selenium.

Houpt, K.A.; Essick, L.A.; Shaw, E.B.; Alo, D.K.; Gilmartin, J.E.; Gutenmann, W.H.; Littman, C.B.; Lisk, D.J.

1988-01-01

126

Relation between Cord Blood Mercury Levels and Early Child Development in a World Trade Center Cohort  

PubMed Central

Objective This study was designed to determine whether prenatal mercury exposure, including potential releases from the World Trade Center (WTC) disaster, adversely affects fetal growth and child development. Methods We determined maternal and umbilical cord blood total mercury of nonsmoking women who delivered at term in lower Manhattan after 11 September 2001, and measured birth outcomes and child development. Results Levels of total mercury in cord and maternal blood were not significantly higher for women who resided or worked within 1 or 2 miles of the WTC in the month after 11 September, compared with women who lived and worked farther away. Average cord mercury levels were more than twice maternal levels, and both were elevated in women who reported eating fish/seafood during pregnancy. Regression analyses showed no significant association between (ln) cord or maternal blood total mercury and birth outcomes. Log cord mercury was inversely associated with the Bayley Scales of Infant Development psychomotor score [Psychomotor Development Index (PDI)] at 36 months (b = –4.2, p = 0.007) and with Performance (b = –3.4, p = 0.023), Verbal (b = –2.9, p = 0.023), and Full IQ scores (b = –3.8, p = 0.002) on the Wechsler Preschool and Primary Scale of Intelligence, Revised (WPPSI-R), at 48 months, after controlling for fish/seafood consumption and other confounders. Fish/seafood consumption during pregnancy was significantly associated with a 5.6- to 9.9-point increase in 36-month PDI, and 48-month Verbal and Full IQ scores. Conclusions Blood mercury was not significantly raised in women living or working close to the WTC site in the weeks after 11 September 2001. Higher cord blood mercury was associated with reductions in developmental scores at 36 and 48 months, after adjusting for the positive effects of fish/seafood consumption during pregnancy. PMID:18709170

Lederman, Sally Ann; Jones, Robert L.; Caldwell, Kathleen L.; Rauh, Virginia; Sheets, Stephen E.; Tang, Deliang; Viswanathan, Sheila; Becker, Mark; Stein, Janet L.; Wang, Richard Y.; Perera, Frederica P.

2008-01-01

127

X-ray fluorescence mercury determination using cation selective membranes at sub-ppb levels.  

PubMed

In the present work a method for the determination of mercury at trace levels by energy dispersive X-ray fluorescence (EDXRF) is introduced. Mercury ions were concentrated on cation selective membranes that have been prepared on Mylar(®) thin film substrate, immobilized on plastic cups. The produced membranes were immersed in water solutions containing low concentrations of mercury. The membranes were left to equilibrate in 1000 mL of mercury solutions and were analyzed by EDXRF. The effects of various experimental parameters were examined. Minimum detection limits of pg mL(-1) (ppt) (0.069 ng mL(-1) for ASTM Type I water and 0.064 ng mL(-1) for seawater) and good linearity were achieved. PMID:24418129

Hatzistavros, Vasilios S; Kallithrakas-Kontos, Nikolaos G

2014-01-27

128

Potential risks of natural mercury levels to wild predator fish in an Amazon reservoir.  

PubMed

Mercury (Hg) is a toxic metal that bioaccumulates in aquatic organisms and along food chain. Many studies have reported the problem of mercury exposure in aquatic systems from Amazon basin, but very few have focused on the potential risks to wild fish. The present study reports the bioaccumulation of mercury and alterations in target organs of the predator fish Hoplias malabaricus (traíra) from Samuel reservoir, Amazon basin, Northern Brazil. About 18% of fish had mercury levels in muscle exceeding the safe limit for ingestion through food, established by WHO (0.5 ?g Hg g(-1)). Fish were separated in two groups according to mercury bioaccumulation in liver (<0.2 ?g Hg g(-1)-group I and >0.2 ?g Hg g(-1)-group II) for biomarker comparisons. Catalase activity and number of macrophage centers were statistically higher in group II, confirming the potential of Hg to interfere with redox balance and to recruit defense cells to the liver. Conversely, erythrocyte nuclear alterations were less frequent in group II, indicating a more rigorous selection of erythrocytes or hormesis pattern of response. Glutathione S-transferase activity, lipid peroxidation, and histopathological analyses were not statistically different in the liver and gills of both groups. Comparison of lipid peroxidation levels of these fish with others captured in Southern Brazil during another study and the high incidence of morphological alterations in the liver and gills suggest that the bioaccumulation of mercury during continuous exposure is posing potential risks to the species. PMID:21927790

da Silva, Grazyelle Sebrenski; Filipak Neto, Francisco; Silva de Assis, Helena Cristina; Bastos, Wanderley Rodrigues; de Oliveira Ribeiro, Ciro Alberto

2012-08-01

129

MEASUREMENT OF MECURY IN FISH SCALES AS AN ASSESSMENT METHOD FOR PREDICTING MUSCLE TISSUE MERCURY CNOCENTRATIONS IN LARGEMOUTH BASS  

EPA Science Inventory

The relationship between total mercury (Hg) concentration in fish scales and in tissues of largemouth bass (Micropterus salmoides) from 20 freshwater sites was developed and evaluated to determine whether scale analysis would allow a non lethal and convenient method for predicti...

130

Tissue Bis(2-ethylhexyl)phthalate Levels in Uremic Subjects  

Microsoft Academic Search

A method for the analysis of tissue DEHP levels was developed. Tissue homogenates were extracted with a chloroformrmethanol solution, followed by the addition of 1 g baked alumina to clean up the heavy matrices of the tissues. DEHP levels in tne tissues were determined by gas chromatography. Percent recovery of DEHP from the tissues ranged between 72.2 and 83.3%.An experimentally

Wenn S. Chen; Julius Kerhay; Karl H. Pearson; Emil P. Paganini; Saturo Nakamoto

1979-01-01

131

40 CFR Table 5 to Subpart IIIii of... - Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans  

Code of Federal Regulations, 2010 CFR

...Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans 5 Table 5 to...Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt...Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans Your...

2010-07-01

132

Comparative observations on levels of mercury in scalp hair of humans from different Islands  

NASA Astrophysics Data System (ADS)

Following the Minamata events, an extraordinary number of studies concerning mercury toxicity and human health have been undertaken. Particular attention has been given to the evaluation of the dose-response relationship, i.e., the body burden at which (evaluated through the mercury analyses in blood or hair) the risk of poisoning begins. The results of a comparative study concerning levels of mercury in the hair of fishermen living in small islands who eat seafood more than four times per week show that in two areas only, and only in a few cases in these areas, the mercury in the hair exceeds the limit at which a possible risk could exist. In fact, the limit of 50 mg/g of total mercury in the hair (indicated as the lower limit above which a possible risk could occur) is surpassed by nine fishermen out of a total of 39 at station 1 and by four fishermen out of a total of 26 at station 3. The average value at station 1 is 36.38 mg/g and that at station 3 is 30.31 mg. Many countries have set legal limits of mercury for seafood, but evidently the system does not offer a true protection for man. Only the provisional tolerable weekly intake (PTWI), as repeatedly suggested by WHO, should be considered the best guideline to prevent possibly harmful consequences.

Renzoni, Aristeo

1992-09-01

133

Achieving very low mercury levels in refinery wastewater by membrane filtration.  

SciTech Connect

Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes were evaluated for their ability to achieve the world's most stringent Hg discharge criterion (<1.3 ng/L) in an oil refinery's wastewater. The membrane processes were operated at three different pressures to demonstrate the potential for each membrane technology to achieve the targeted effluent mercury concentrations. The presence of mercury in the particulate form in the refinery wastewater makes the use of MF and UF membrane technologies more attractive in achieving very low mercury levels in the treated wastewater. Both NF and RO were also able to meet the target mercury concentration at lower operating pressures (20.7 bar). However, higher operating pressures ({ge}34.5 bar) had a significant effect on NF and RO flux and fouling rates, as well as on permeate quality. SEM images of the membranes showed that pore blockage and narrowing were the dominant fouling mechanisms for the MF membrane while surface coverage was the dominant fouling mechanism for the other membranes. The correlation between mercury concentration and particle size distribution was also investigated to understand mercury removal mechanisms by membrane filtration. The mean particle diameter decreased with filtration from 1.1 {+-} 0.0 {micro}m to 0.74 {+-} 0.2 {micro}m after UF.

Urgun Demirtas, M.; Benda, P.; Gillenwater, P. S.; Negri, M. C.; Xiong, H.; Snyder, S. W. (Center for Nanoscale Materials); ( ES)

2012-05-15

134

Mercury in freshwater fish of northeast North America--a geographic perspective based on fish tissue monitoring databases.  

PubMed

As part of an initiative to assemble and synthesize mercury (Hg) data from environmental matrices across northeastern North America, we analyzed a large dataset comprised of 15,305 records of fish tissue Hg data from 24 studies from New York State to Newfoundland. These data were summarized to provide mean Hg concentrations for 40 fish species and associated families. Detailed analyses were carried out using data for 13 species. Hg in fishes varied by geographic area, waterbody type, and waterbody. The four species with the highest mean Hg concentrations were muskellunge (Esox masquinongy), walleye (Sander vitreus), white perch (Morone americana), and northern pike (Esox luscius). Several species displayed elevated Hg concentrations in reservoirs, relative to lakes and rivers. Normalized deviations from mean tissue levels for yellow perch (Perca flavescens) and brook trout (Salvelinus fontinalis) were mapped, illustrating how Hg concentrations in these species varied across northeastern North America. Certain geographic regions showed generally below or above-average Hg concentrations in fish, while significant heterogeneity was evident across the landscape. The proportion of waterbodies exhibiting exceedances of USEPA's criterion for fish methylmercury ranged from 14% for standard-length brook trout fillets to 42% for standard-length yellow perch fillets. A preliminary correlation analysis showed that fish Hg concentrations were related to waterbody acidity and watershed size. PMID:15931965

Kamman, Neil C; Burgess, Neil M; Driscoll, Charles T; Simonin, Howard A; Goodale, Wing; Linehan, Janice; Estabrook, Robert; Hutcheson, Michael; Major, Andrew; Scheuhammer, Anton M; Scruton, David A

2005-03-01

135

Mercury concentrations in seabird tissues from Machias Seal Island, New Brunswick, Canada  

Microsoft Academic Search

Mercury is a pervasive environmental contaminant, the anthropogenic portion of which is increasing globally, and in northeastern North America in particular. Seabirds frequently are used as indicators of the marine environment, including mercury contamination. We analysed paired samples for total mercury (Hg) concentrations in feathers and blood from adult and chick, albumen, and lipid-free yolk of seven seabirds breeding on

Alexander L. Bond; Antony W. Diamond

2009-01-01

136

Electronic Characterization of Defects in Narrow Gap Semiconductors-Comparison of Electronic Energy Levels and Formation Energies in Mercury Cadmium Telluride, Mercury Zinc Telluride, and Mercury Zinc Selenide  

NASA Technical Reports Server (NTRS)

We have used a Green's function technique to calculate the energy levels and formation energy of deep defects in the narrow gap semiconductors mercury cadmium telluride (MCT), mercury zinc telluride (MZT) and mercury zinc selenide (MZS). The formation energy is calculated from the difference between the total energy with an impurity cluster and the total energy for the perfect crystal. Substitutional (including antisite), interstitial (self and foreign), and vacancy deep defects are considered. Relaxation effects are calculated (with molecular dynamics). By use of a pseudopotential, we generalize the ideal vacancy model so as to be able to consider relaxation for vacancies. Different charge states are considered and the charged state energy shift (as computed by a modified Haldane-Anderson model) can be twice that due to relaxation. Different charged states for vacancies were not calculated to have much effect on the formation energy. For all cases we find deep defects in the energy gap only for cation site s-like orbitals or anion site p-like orbitals, and for the substitutional case only the latter are appreciably effected by relaxation. For most cases for MCT, MZT, MZS, we consider x (the concentration of Cd or Zn) in the range appropriate for a band gap of 0.1 eV. For defect energy levels, the absolute accuracy of our results is limited, but the precision is good, and hence chemical trends are accurately predicted. For the same reason, defect formation energies are more accurately predicted than energy level position. We attempt, in Appendix B, to calculate vacancy formation energies using relatively simple chemical bonding ideas due to Harrison. However, these results are only marginally accurate for estimating vacancy binding energies. Appendix C lists all written reports and publications produced for the grant. We include abstracts and a complete paper that summarizes our work which is not yet available.

Patterson, James D.

1996-01-01

137

Relating Land Cover Characteristics and Common Loon Mercury Levels Using Geographic Information Systems  

Microsoft Academic Search

This effort models the relationship between mercury (Hg) levels in the common loon (Gavia immer) and land cover types as defined by the National Land Cover Database (NLCD). We constructed the model within the framework of a GIS to analyze the spatial relationships between land cover types and blood Hg levels in male common loons. Thiessan polygons were used to

David Kramar; Wing M. Goodale; L. M. Kennedy; L. W. Carstensen; Taranjat Kaur

2005-01-01

138

Total mercury and methylmercury levels in fish from hydroelectric reservoirs in Tanzania.  

PubMed

Total mercury (THg) and methylmercury (MeHg) levels have been determined in fish species representing various tropic levels in four major hydroelectric reservoirs (Mtera, Kidatu, Hale-Pangani, Nyumba ya Mungu) located in two distinct geographical areas in Tanzania. The Mtera and Kidatu reservoirs are located along the Great Ruaha River drainage basin in the southern central part of the country while the other reservoirs are located within the Pangani River basin in the north eastern part of Tanzania. Fish mercury levels ranged from 5 to 143 microg/kg (mean 40 microg/kg wet weight) in the Mtera Reservoir, and from 7 to 119 microg/kg (mean 21 microg/kg) in the Kidatu Reservoir downstream of the Great Ruaha River. The lowest THg levels, in the range 1-10 microg/kg (mean 5 microg/kg), were found in fish from the Nyumba ya Mungu (NyM) Reservoir, which is one of the oldest reservoirs in the country. Fish mercury levels in the Pangani and Hale mini-reservoirs, downstream of the NyM Reservoir, were in the order of 3-263 microg/kg, with an average level of 21 microg/kg. These THg levels are among the lowest to be reported in freshwater fish from hydroelectric reservoirs. Approximately 56-100% of the total mercury in the fish was methylmercury. Herbivorous fish species contained lower THg levels than the piscivorous species; this was consistent with similar findings in other fish studies. In general the fish from the Tanzanian reservoirs contained very low mercury concentrations, and differed markedly from fish in hydroelectric reservoirs of similar age in temperate and other regions, which are reported to contain elevated mercury concentrations. The low levels of mercury in the fish correlated with low background concentrations of THg in sediment and flooded soil (mean 2-8 microg/kg dry weight) in the reservoir surroundings. This suggested a relatively clean reservoir environment that has not been significantly impacted by mercury contamination from natural or anthropogenic sources. PMID:12663196

Ikingura, J R; Akagi, H

2003-03-20

139

The Level of Mercury in Human Dental Plaque and Interaction in vitro between Biofilms of Streptococcus mutans and Dental Amalgam  

Microsoft Academic Search

Mercury levels (ug\\/mg dry weight) in dental plaque from amalgam and enamel surfaces in human subjects with amalgam restorations were (range, mean, SD) 0.5-1.31, 0.72,0.34 and 0.01-0.54, 0.2, 0.19, respectively. The levels of mercury in plaque from amalgam surfaces were significantly higher than those from plaque on enamel (p < 0.001). No mercury was detected in plaque from subjects without

H. A. Lyttle; G. H. Bowden

1993-01-01

140

Pituitary gland levels of mercury, selenium, iron, and zinc in an Alzheimer`s disease study  

SciTech Connect

Mercury, iron, selenium, and zinc imbalances have been observed in comparisons between Alzheimer`s disease (AD) and control subject brains. Analyses of the pituitary gland have demonstrated that this organ retains relatively high concentrations of trace elements, including mercury, iron, and zinc. Our previous work has shown that the pituitary glands of AD and control subjects are typically higher in these trace elements than brain samples from the same subject. Instrumental neutron activation analysis (INAA) was used to compare the pituitary trace element levels of AD and control subjects. This study also describes the intrasubject relationships of brain trace element levels to those in the pituitary gland of AD and control subjects.

Cornett, C.R.; Markesbery, W.R.; Wekstein, D.R.; Ehmann, W.D. [Univ. of Kentucky, Lexington, KY (United States)

1996-12-31

141

Projections of atmospheric mercury levels and their effect on air quality in the United States  

NASA Astrophysics Data System (ADS)

The individual and combined effects of global climate change and emissions changes from 2000 to 2050 on atmospheric mercury levels in the United States are investigated by using the global climate-chemistry model, CAM-Chem, coupled with a mercury chemistry-physics mechanism (CAM-Chem/Hg). Three future pathways from the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) are considered, with the A1FI, A1B and B1 scenarios representing the upper, middle and lower bounds of potential climate warming, respectively. The anthropogenic and biomass burning emissions of mercury are projected from the energy use assumptions in the IPCC SRES report. Natural emissions from both land and ocean sources are projected by using dynamic schemes. TGM concentration increases are greater in the low latitudes than they are in the high latitudes, indicative of a larger meridional gradient than in the present day. In the A1FI scenario, TGM concentrations in 2050 are projected to increase by 2.1-4.0 ng m-3 for the eastern US and 1.4-3.0 ng m-3 for the western US. This spatial difference corresponds to potential increases in wet deposition of 10-14 ?g m-2 for the eastern US and 2-4 ?g m-2 for the western US. The increase in Hg(II) emissions tends to enhance wet deposition and hence increase the risk of higher mercury entering the hydrological cycle and ecosystem. In the B1 scenario, mercury concentrations in 2050 are similar to present level concentrations; this finding indicates that the domestic reduction in mercury emissions is essentially counteracted by the effects of climate warming and emissions increases in other regions. The sensitivity analyses show that changes in anthropogenic emissions contribute 32-53% of projected changes in mercury air concentration, while the independent contribution by climate change and its induced natural emissions change accounts for 47-68%.

Lei, H.; Wuebbles, D. J.; Liang, X.-Z.; Tao, Z.; Olsen, S.; Artz, R.; Ren, X.; Cohen, M.

2014-01-01

142

Predicting DNA methylation level across human tissues  

PubMed Central

Differences in methylation across tissues are critical to cell differentiation and are key to understanding the role of epigenetics in complex diseases. In this investigation, we found that locus-specific methylation differences between tissues are highly consistent across individuals. We developed a novel statistical model to predict locus-specific methylation in target tissue based on methylation in surrogate tissue. The method was evaluated in publicly available data and in two studies using the latest IlluminaBeadChips: a childhood asthma study with methylation measured in both peripheral blood leukocytes (PBL) and lymphoblastoid cell lines; and a study of postoperative atrial fibrillation with methylation in PBL, atrium and artery. We found that our method can greatly improve accuracy of cross-tissue prediction at CpG sites that are variable in the target tissue [R2 increases from 0.38 (original R2 between tissues) to 0.89 for PBL-to-artery prediction; from 0.39 to 0.95 for PBL-to-atrium; and from 0.81 to 0.98 for lymphoblastoid cell line-to-PBL based on cross-validation, and confirmed using cross-study prediction]. An extended model with multiple CpGs further improved performance. Our results suggest that large-scale epidemiology studies using easy-to-access surrogate tissues (e.g. blood) could be recalibrated to improve understanding of epigenetics in hard-to-access tissues (e.g. atrium) and might enable non-invasive disease screening using epigenetic profiles. PMID:24445802

Ma, Baoshan; Wilker, Elissa H.; Willis-Owen, Saffron A. G.; Byun, Hyang-Min; Wong, Kenny C. C.; Motta, Valeria; Baccarelli, Andrea A.; Schwartz, Joel; Cookson, William O. C. M.; Khabbaz, Kamal; Mittleman, Murray A.; Moffatt, Miriam F.; Liang, Liming

2014-01-01

143

A statistical model and national data set for partioning fish-tissue mercury concentration variation between spatiotemporal and sample characteristic effects  

USGS Publications Warehouse

Many Federal, Tribal, State, and local agencies monitor mercury in fish-tissue samples to identify sites with elevated fish-tissue mercury (fish-mercury) concentrations, track changes in fish-mercury concentrations over time, and produce fish-consumption advisories. Interpretation of such monitoring data commonly is impeded by difficulties in separating the effects of sample characteristics (species, tissues sampled, and sizes of fish) from the effects of spatial and temporal trends on fish-mercury concentrations. Without such a separation, variation in fish-mercury concentrations due to differences in the characteristics of samples collected over time or across space can be misattributed to temporal or spatial trends; and/or actual trends in fish-mercury concentration can be misattributed to differences in sample characteristics. This report describes a statistical model and national data set (31,813 samples) for calibrating the aforementioned statistical model that can separate spatiotemporal and sample characteristic effects in fish-mercury concentration data. This model could be useful for evaluating spatial and temporal trends in fishmercury concentrations and developing fish-consumption advisories. The observed fish-mercury concentration data and model predictions can be accessed, displayed geospatially, and downloaded via the World Wide Web (http://emmma.usgs.gov). This report and the associated web site may assist in the interpretation of large amounts of data from widespread fishmercury monitoring efforts.

Wente, Stephen P.

2004-01-01

144

Shifts in relative tissue delta15N values in snowy egret nestlings with dietary mercury exposure: a marker for increased protein degradation.  

PubMed

Shifts in tissue nitrogen isotope composition may be a more sensitive general indicator of stress than measurement of high-turnover defensive biomolecules such as metallothionein and glutathione. As a physical resource transmitted along the trophic web, perturbations in protein nitrogen metabolism may also help resolve issues concerning the effects of contaminants on organisms and their consequential hierarchical linkages in ecotoxicology. Snowy egret nestlings (Egretta thula) fed mercury-contaminated diets of constant nitrogen isotope composition exhibited increased relative delta15N values in whole liver (p = 0.0011) and the acid-soluble fraction (ASF) of the liver (p = 0.0005) when compared to nestlings fed a reference diet. When nitrogen isotope data were adjusted for the source term of the diet, liver mercury concentrations corresponded with both whole liver relative 15N enrichment (r2 = 0.79, slope 0.009, p < 0.0001) and relative 15N enrichment in the acid-soluble fraction of the liver (r2 = 0.85, slope 0.026, p < 0.0001). Meanwhile, significant differences were not observed in hepatic levels of the metal-binding peptides metallothionein and glutathione despite a nearly 3-fold difference in liver mercury content. Because increases in tissue delta15N values result from increased rates of protein breakdown relative to synthesis, we propose that the increased relative liver delta15N values reflect a shift in protein metabolism. The relationship between ASF and mercury was significantly stronger (p < 0.0001) than that for whole liver, suggesting that the relationship is driven by an increase in bodily derived amino acids in the acid-soluble, free amino acid pool. PMID:15984804

Shaw-Allen, Patricia L; Romanek, Christopher S; Bryan, A L; Brant, Heather; Jagoe, Charles H

2005-06-01

145

Mercury level in fish caught in Indian River Lagoon higher than it should be?  

E-print Network

Mercury level in fish caught in Indian River Lagoon higher than it should be? Harbor Branch launches new study of humans who eat fish and live around the estuary By Scott Wyland Tuesday, May 22, 2012 INDIAN RIVER COUNTY -- A 20-year-old man fishes local waters every day for his meals and scoffs

Belogay, Eugene A.

146

Human hair mercury levels in Tucuruí area, State of Pará, Brazil.  

PubMed

The environmental mercury contamination at the Tucuruí water reservoir was studied by measuring the amount of mercury in human hair samples collected from fishermen and their families. Samples were also collected from the Parakanã Indian reservation in the vicinity to give information about the background levels in the area. The mercury concentrations in hair samples ranged from 0.9 to 240 mg/kg. The mean value in the main reservoir was 65 mg/kg. Seven values exceeded 100 mg/kg and 31 values exceeded 50 mg/kg. The hair Hg concentrations amongst the fishermen in Tucuruí reservoir are high enough to cause health effects. The fetal exposure is especially alarming. Changes in gold mining practises and in the human diet are recommended. PMID:8560241

Leino, T; Lodenius, M

1995-12-11

147

Mercury levels and potential risk from subsistence foods from the Aleutians.  

PubMed

Considerable attention has been devoted to contaminants (mainly PCBs and mercury) in subsistence foods (particularly fish) from various parts of the world. However, relatively little attention has been devoted to examining mercury levels in a full range of subsistence foods from a particular region. While managers and scientists compute risk based on site-specific data on contaminant levels and consumption rates, a first step in making risk decisions by subsistence peoples is knowledge about the relative levels of mercury in the foods they eat. This study examined levels of mercury in subsistence foods (edible components) from several islands in the western Aleutians of Alaska, including algae (4 species), invertebrates (9 species), fish (15 species) and birds (5 species). Samples were gathered by both subsistence hunters/fishers and by scientists using the same equipment. Another objective was to determine if there were differences in mercury levels in subsistence foods gathered from different Aleutian islands. We tested the null hypotheses that there were no interspecific and interisland differences in mercury levels. Because of variation in distribution and the nature of subsistence hunting and fishing, not all organisms were collected from each of the islands. There were significant and important differences in mercury levels among species, but the locational differences were rather small. There was an order of magnitude difference between algae/some invertebrates and fish/birds. Even within fish, there were significant differences. The highest mean mercury levels were in flathead sole (Hippoglossoides elassodon, 0.277 ppm), yellow irish lord (Hemilepidotus jardani, 0.281 ppm), great sculpin (Myoxocephalus polyacanthocephalus, 0.366 ppm), glaucous-winged gull (Larus glaucescens, 0.329 ppm) and its eggs (0.364 ppm), and pigeon guillemot (Cepphus columba, 0.494 ppm). Mercury levels increased with increasing weight of the organisms for limpets (Tectura scutum), and for 11 of the 15 fish species examined. Nine of the 15 fish species had some samples over the 0.3 ppm level, and 7 of 15 fish had some samples over 0.5 ppm. For birds, 95% of the pigeon guillemot muscle samples were above the 0.3 ppm, and 43% were above 0.5 ppm. While health professionals may argue about the risk and benefits of eating fish, and of eating alternative protein sources, the public should be provided with enough information for them to make informed decisions. This is particularly true for subsistence people who consume large quantities of self-caught foods, particularly for sensitive sub-populations, such as pregnant women. We argue that rather than giving people blanket statements about the health benefits or risks from eating fish, information on mean and maximum mercury levels should also be provided on a wide range of subsistence foods, allowing informed decisions, especially by those most at risk. PMID:17590413

Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Burke, Sean; Stamm, Tim; Snigaroff, Ronald; Snigaroff, Dan; Patrick, Robert; Weston, Jim

2007-10-01

148

A gravimetric approach to providing SI traceability for concentration measurement results of mercury vapor at ambient air levels  

NASA Astrophysics Data System (ADS)

Current measurement and calibration capabilities for mercury vapor in air are maintained at levels of 0.2–40??g?Hg?m?3. In this work, a mercury vapor generator has been developed to establish metrological traceability to the international system of units (SI) for mercury vapor measurement results ?15?ng?Hg?m?3, i.e. closer to realistic ambient air concentrations (1–2?ng?Hg?m?3) [1]. Innovations developed included a modified type of diffusion cell, a new measurement method to weigh the loss in (mercury) mass of these diffusion cells during use (ca. 6–8??g mass difference between successive weighings), and a new housing for the diffusion cells to maximize flow characteristics and to minimize temperature variations and adsorption effects. The newly developed mercury vapor generator system was tested by using diffusion cells generating 0.8 and 16?ng?Hg?min?1. The results also show that the filter system, to produce mercury free air, is working properly. Furthermore, and most importantly, the system is producing a flow with a stable mercury vapor content. Some additional improvements are still required to allow the developed mercury vapor generator to produce SI traceable mercury vapor concentrations, based upon gravimetry, at much lower concentration levels and reduced measurement uncertainties than have been achieved previously. The challenges to be met are especially related to developing more robust diffusion cells and better mass measurement conditions. The developed mercury vapor generator will contribute to more reliable measurement results of mercury vapor at ambient and background air levels, and also to better safety standards and cost reductions in industrial processes, such as the liquefied natural gas field, where aluminum main cryogenic heat exchangers are used which are particularly prone to corrosion caused by mercury.

Ent, Hugo; van Andel, Inge; Heemskerk, Maurice; van Otterloo, Peter; Bavius, Wijnand; Baldan, Annarita; Horvat, Milena; Brown, Richard J. C.; Quétel, Christophe R.

2014-11-01

149

Mercury speciation in brain tissue of polar bears (Ursus maritimus) from the Canadian Arctic.  

PubMed

Methylmercury (MeHg) is a neurotoxicant that has been found at elevated concentrations in the Arctic ecosystem. Little is known about its internal dose in wildlife such as polar bears. We measured concentrations of mercury (Hg) in three different brain regions (cerebellum, frontal lobe and brain stem) of 24 polar bears collected from the Nunavik, Canada between 2000 and 2003. Speciation of Hg was measured by High Performance Liquid Chromatography coupled to Inductively Coupled Plasma Mass Spectroscopy (HPLC-ICP-MS). Concentrations of mean total Hg in brain tissue were up to 625 times lower (0.28 ± 0.07 mg kg(-1) dry weight (dw) in frontal lobe, 0.23 ± 0.07 mg kg(-1) dw in cerebellum and 0.12 ± 0.0 3mg kg(-1) dw in brain stem) than the mean total Hg concentration previously reported in polar bear liver collected from Eastern Baffin Island. Methylmercury (MeHg) accounted for 100% of the Hg found in all three brain regions analyzed. These results suggest that polar bear might reduce the toxic effects of Hg by limiting the uptake into the brain and/or decrease the rate of demethylation so that Hg can be excreted from the brain more easily. The toxicokinetics and the blood-brain-barrier mechanisms of polar bears are still unknown and further research is required. PMID:22406289

Krey, Anke; Kwan, Michael; Chan, Hing Man

2012-04-01

150

Tissue mercury concentrations and adrenocortical responses of female big brown bats (Eptesicus fuscus) near a contaminated river.  

PubMed

Much of the research on mercury (Hg) in wild vertebrates has focused on piscivores and other animals at high trophic levels. However, recent studies indicated that insectivorous terrestrial vertebrates may also be at risk. In the present study, we examined blood and fur Hg concentrations as well as the adrenocortical responses of insectivorous big brown bats (Eptesicus fuscus) near the Hg-contaminated South River, VA and a nearby reference area. Baseline glucocorticoids and adrenocortical responses to handling have been widely used to assess the influence of environmental stressors because plasma glucocorticoids rise in response to various physical, psychological, and physiological challenges. Female bats captured at the contaminated site had 2.6 times higher blood and fur Hg concentrations than those captured at the reference site (blood: 0.11 vs. 0.04 ?g/g wet weight; fur: 28.0 vs. 10.9 ?g/g fresh weight). Fur Hg concentrations at the contaminated site were higher than most wild omnivorous and carnivorous mammals reported in the literature. Although fur and blood Hg concentrations were tightly correlated, fur Hg concentrations averaged 260 times higher than concentrations in blood. This suggests that fur may be an important depuration route for bats, just as it is in other mammals. Despite the high Hg concentrations in bat tissue, we did not observe any site difference in adrenocortical responses. Our results suggest that the bats at the contaminated site were exposed to Hg concentrations below those causing adverse effects on their adrenal axis. PMID:20596767

Wada, Haruka; Yates, David E; Evers, David C; Taylor, Robert J; Hopkins, William A

2010-10-01

151

Mercury contamination in human hair and fish from Cambodia: levels, specific accumulation and risk assessment.  

PubMed

Mercury (Hg) concentrations in human hair and fish samples from Phnom Penh, Kien Svay, Tomnup Rolork and Batrong, Cambodia, collected in November 1999 and December 2000 were determined to understand the status of contamination, and age- and sex-dependent accumulation in humans and to assess the intake of mercury via fish consumption. Mercury concentrations in human hair ranged from 0.54 to 190mug/g dry wt. About 3% of the samples contained Hg levels exceeding the no observed adverse effects level (NOAEL) of WHO (50mug/g) and the levels in some hair samples of women also exceeded the NOAEL (10mug/g) associated with fetus neurotoxicity. A weak but significant positive correlation was observed between age and Hg levels in hair of residents. Mercury concentrations in muscle of marine and freshwater fish from Cambodia ranged from <0.01 to 0.96mug/g wet wt. Mercury intake rates were estimated on the basis of the Hg content in fish and daily fish consumption. Three samples of marine fish including sharp-tooth snapper and obtuse barracuda, and one sample of sharp-tooth snapper exceeded the guidelines by US EPA and by Joint FAO/WHO Expert Committee on Food Additives (JECFA), respectively, which indicates that some fish specimens examined (9% and 3% for US EPA and JECFA guidelines, respectively) were hazardous for consumption at the ingestion rate of Cambodian people (32.6g/day). It is suggested that fish is probably the main source of Hg for Cambodian people. However, extremely high Hg concentrations were observed in some individuals and could not be explained by Hg intake from fish consumption, indicating some other contamination sources of Hg in Cambodia. PMID:15572226

Agusa, Tetsuro; Kunito, Takashi; Iwata, Hisato; Monirith, In; Tana, Touch Seang; Subramanian, Annamalai; Tanabe, Shinsuke

2005-03-01

152

Urinary mercury levels in females: Influence of skin-lightening creams and dental amalgam fillings  

Microsoft Academic Search

The influence of application of skin-lightening creams and dental amalgam fillings on the urinary mercury (Hg) level was evaluated in 225 females (ages 17 to 58 years) living in Riyadh, capital of Saudi Arabia. The arithmetic mean of the urinary Hg level was 6.96 ± 20.43 µg l, in the range 0 to 204.8 µg l. The mean urinary Hg

Iman Al-Saleh; Neptune Shinwari

1997-01-01

153

Mercury speciation in fish tissues from a Mediterranean River basin: the Tagus River (central Spain) as a case study.  

PubMed

An assessment of mercury (Hg) accumulation in fish from the Tagus River aquatic system (central Spain), which has been influenced by pollution from industrial and urban development, was performed. Total Hg (THg), inorganic Hg (IHg), and monomethylmercury (MMHg) were determined in muscle and liver of different fish species, including Cyprinus carpio, Ameiurus melas, and Chondrostoma miegii, sampled from three locations. Although concentrations of THg and Hg species showed wide variability among the fish species, they were also found to be considerably dependent on location and fish tissue. Relative contents of MMHg to THg in muscle varied from 60 to 88%, whereas those found in liver ranged from 7 to 59%. Mean THg concentrations ranged from 126 to 810 ng/g (dry weight [dw]) in liver and from 159 to 1057 ng/g dw in muscle. Therefore, the mean THg concentration in all fish muscle samples was far lower than the maximum residue level recommended by the European Union for fishery products. Nevertheless, the concentrations of Hg in fish muscle reported in this study were somewhat increased compared with other areas geographically distant from most major anthropogenic Hg sources and, in some cases, even greater than those previously reported elsewhere in more polluted areas. In contrast, Hg contents in liver were lower than those found in Hg-contaminated areas, but they were within the range found in other areas exposed to diffuse sources of pollution by Hg. Thus, this article provides an overview of the concentration and distribution of Hg species in fish muscle and liver tissues samples taken from a freshwater system in the Mediterranean River basin. PMID:21472454

Nevado, J J Berzas; Martín-Doimeadios, R C Rodríguez; Bernardo, F J Guzmán; Moreno, M Jiménez; Ropero, M J Patiño; Serrano, A de Marcos

2011-11-01

154

Metal levels in tissues of Eurasian otters (Lutra lutra) from Hungary: variation with sex, age, condition and location.  

PubMed

Liver samples of Eurasian otters from various parts of Hungary were analysed for mercury, copper, zinc, lead and cadmium. Only zinc concentration was significantly higher in females. Higher mercury and cadmium concentrations in adults and higher zinc values in immature otters were measured. Accumulation of mercury, copper and zinc in tissues increased with the declining condition of animals. Mercury and copper were detected with higher values in samples from large rivers. PMID:19036400

Lanszki, József; Orosz, Eniko; Sugár, László

2009-02-01

155

Dental silver tooth fillings: A source of mercury exposure revealed by whole-body image scan and tissue analysis  

SciTech Connect

Mercury (Hg) vapor is released from dental silver tooth fillings into human mouth air after chewing, but its possible uptake routes and distribution among body tissues are unknown. This investigation demonstrates that when radioactive 203Hg is mixed with dental Hg/silver fillings (amalgam) and placed in teeth of adult sheep, the isotope will appear in various organs and tissues within 29 days. Evidence of Hg uptake, as determined by whole-body scanning and measurement of isotope in specific tissues, revealed three uptake sites: lung, gastrointestinal, and jaw tissue absorption. Once absorbed, high concentrations of dental amalgam Hg rapidly localize in kidneys and liver. Results are discussed in view of potential health consequences from long-term exposure to Hg from this dental material.

Hahn, L.J.; Kloiber, R.; Vimy, M.J.; Takahashi, Y.; Lorscheider, F.L. (Univ. of Calgary, Alberta (Canada))

1989-12-01

156

Changes in premature infant mercury and lead blood levels after blood transfusions.  

PubMed

Objective?To describe the blood level changes of mercury and lead after packed red blood cell (PRBC) transfusions in???750?g birth weight infants. Study Design?Heavy metal blood levels were measured in infants in PRBC units on 1st, 4th, 5th, and 7th days (D1, D4, D5, and D7) of life and in urine on D1, D4, and D7. Results?A total of 10 infants were enrolled with a mean birth weight of 632?±?72 g. Out of which nine infants received one or more PRBC transfusions, with an average of 2.9?±?2.5 transfusions per infant. Heavy metals were detected in all the transfusions. The average mercury level was 1.33 µg/L on D1 and 1.66 µg/L on D7, p?>?0.05. The average lead level was 0.32 µg/dL on D1 and 0.56 µg/dL on D7, p?>?0.05. Urinary mercury excretion increased in infants with no bowel movements. Urinary excretion of lead decreased over time as blood levels increased. Conclusions?After receiving blood transfusions, the blood levels of mercury and lead were maintained at the end of the 1st week of life. As there is no evidence of a proportionate increase in excretory amounts of these heavy metals, there is a concern that they are retained and potentially exert toxic effects. PMID:24347256

Elabiad, Mohamad T; Christensen, Michael

2014-11-01

157

Deficiency of Activating Fc?-Receptors Reduces Hepatic Clearance and Deposition of IC and Increases CIC Levels in Mercury-Induced Autoimmunity  

PubMed Central

Background Inorganic mercury (Hg) induces a T-cell dependent, systemic autoimmune condition (HgIA) where activating Fc?-receptors (Fc?Rs) are important for the induction. In this study we examined the influence of activating Fc?Rs on circulating levels and organ localization of immune complexes (IC) in HgIA. Methods and Principal Findings Mercury treated BALB/c wt mice showed a significant but modest increase of circulating IC (CIC) from day 12 until day 18 and day 35 for IgG2a- and IgG1- CIC, respectively. Mercury-treated mice lacking the trans-membrane ?-chain of activating Fc?Rs (FcR??/?) had significantly higher CIC levels of both IgG1-CIC and IgG2a-CIC than wt mice during the treatment course. The hepatic uptake of preformed CIC was significantly more efficient in wt mice compared to Fc?R?/? mice, but also development of extrahepatic tissue IC deposits was delayed in FcR??/? mice. After 35 days of Hg treatment the proportion of immune deposits, as well as the amounts was significantly reduced in vessel FcR??/? mice compared to wt mice. Conclusions We conclude that mice lacking functional activating Fc?Rs respond to Hg with increased levels and altered quality of CIC compared with wt mice. Lack of functional activating Fc?Rs delayed the elimination of CIC, but also significantly reduced extrahepatic tissue localization of CIC. PMID:20976163

Martinsson, Klara; Skogh, Thomas; Mousavi, Seyed Ali; Berg, Trond; Jonsson, Jan-Ingvar; Hultman, Per

2010-01-01

158

SPATIAL VARIATION AND CORRELATIONS OF MERCURY LEVELS IN THE TERRESTRIAL AND AQUATIC COMPONENTS OF A  

E-print Network

of Kejimkujik Park, Nova Scotia. Mercury concentrations in five-year-old yellow perch (age based on regression with mercury in lake waters and yellow perch. No correlations were observed between mercury in terrestrial components and mercury in yellow perch; however, mercury in yellow perch was correlated with P in leaf

O'Driscoll, Nelson

159

Mercury distribution in blood, tissues, and feathers of double-crested cormorant nestlings from arid-lands reservoirs in south central New Mexico.  

PubMed

Eggs, blood, liver, muscle, and feathers were analyzed for concentrations of total mercury in double-crested cormorant (Phalacrocorax auritus) nestlings from two reservoirs in south central New Mexico. Total mercury concentrations among eggs, tissues, and feathers were not significantly correlated. Concentrations of total mercury averaged 0.40 microg/g in liver and 0.18 microg/g in muscle tissues in both populations of nestlings. There were no significant changes in concentrations of total mercury in whole blood of nestlings collected 7-10 days and 17-22 days posthatch in Caballo Reservoir (0.36 microg/g and 0.39 microg/g, respectively) and in Elephant Butte Reservoir (0.36 microg/g and 0.34 microg/g, respectively). Total mercury concentrations were similar for blood, muscle, and liver in nestlings for both reservoirs. Total mercury concentrations were higher in eggs and tail, primary, and secondary feathers from nestlings at Caballo Reservoir compared to Elephant Butte Reservoir. Although there were no differences in concentrations of total mercury in fishes between the two reservoirs, bioaccumulation and biomagnification was evident in planktivorous and piscivorous fishes. The data demonstrate that feather analysis may not be a good predictor of tissue burden in nestlings from regions of low contamination. PMID:10227865

Caldwell, C A; Arnold, M A; Gould, W R

1999-05-01

160

USE OF THE GEOGRAPHIC INFORMATION SYSTEM TO INVESTIGATE MERCURY LEVELS IN CORRELATION WITH POSTMORTEM FINDINGS OF ASPERGILLUS INDUCED LESIONS IN THE COMMON LOON (GAVIA IMMER) IN THE NORTHEASTERN USA  

EPA Science Inventory

This study employed the Geographic Information System (GIS) to correlate total mercury levels in liver tissue with post-mortem findings of aspergillosis in common loons (Gavia immer) in the northeast United States of America (USA). Aspergillosis is an opportunistic fungal infecti...

161

Seasonal Changes and Tissue Distribution of Mercury in Largemouth Bass ( Micropterus salmoides ) from Dorena Reservoir, Oregon  

Microsoft Academic Search

.   Mercury contamination in fish has lead to the issuance of fish consumption advisories in many water bodies of the United\\u000a States. There is evidence that mercury concentrations may fluctuate seasonally, which could affect consumption advisories.\\u000a Largemouth bass (Micropterus salmoides) were collected from Dorena Reservoir, Oregon, in spring and summer of 1995 and spring, summer, and fall of 1996. Samples

E. P. Foster; D. L. Drake; G. DiDomenico

2000-01-01

162

Investigation of mercury levels in soil around a municipal solid waste incinerator in Shenzhen, China  

Microsoft Academic Search

Within the management hierarchy of municipal solid waste (MSW), incineration with energy recovery is a desired and viable\\u000a option often used in densely populated and economically developed cities. The gaseous and particulate mercury (Hg) emitted\\u000a from MSW incinerators may accumulate in the soil entering via dry and wet deposition. To investigate the soil Hg level and\\u000a estimate the effects of

Jun-Jian Wang; Hong-Wei Zhao; Xiu-Ping Zhong; Si-Fang Kong; Yang-Sheng Liu; Hui Zeng

163

Mercury Contamination of Aquatic Ecosystems  

NSDL National Science Digital Library

This United States Geological Survey (USGS) factsheet contains information about US mercury contamination. Issues discussed include how mercury becomes a toxicological problem through bioaccumulation, human effects of mercury toxicity, and levels of atmospheric mercury. Mercury levels in fish are examined to determine how mercury gets into the environment and into the food chain.

Krabbenhoft, D. P.; Rickert, D. A.

164

DNA barcodes reveal species-specific mercury levels in tuna sushi that pose a health risk to consumers  

PubMed Central

Excessive ingestion of mercury—a health hazard associated with consuming predatory fishes—damages neurological, sensory-motor and cardiovascular functioning. The mercury levels found in Bigeye Tuna (Thunnus obesus) and bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus), exceed or approach levels permissible by Canada, the European Union, Japan, the US, and the World Health Organization. We used DNA barcodes to identify tuna sushi samples analysed for mercury and demonstrate that the ability to identify cryptic samples in the market place allows regulatory agencies to more accurately measure the risk faced by fish consumers and enact policies that better safeguard their health. PMID:20410032

Lowenstein, Jacob H.; Burger, Joanna; Jeitner, Christian W.; Amato, George; Kolokotronis, Sergios-Orestis; Gochfeld, Michael

2010-01-01

165

Mercury dynamics in young Common Tern (Sterna hirundo) chicks from a polluted environment.  

PubMed

: We studied mercury concentrations and amounts in tissues of 19 starved young Common Tern chicks (median age 4 days) and in eggs from the same colony. Concentrations and burden were similar between eggs and newly hatched chicks. Mercury concentrations were highest in down, which contained at least 38% of the body mercury. The mercury burden of the whole body and of the tissues as well as the concentration in down increased with age and body mass, indicating the importance of down as an elimination pathway. Conversion ratios between mercury concentrations in tissues and the whole chick body varied according to the contamination level. PMID:24203117

Becker, P H; Furness, R W; Henning, D

1993-03-01

166

GOAT ADIPOSE TISSUE MOBILIZATION AND MILK PRODUCTION LEVEL  

E-print Network

GOAT ADIPOSE TISSUE MOBILIZATION AND MILK PRODUCTION LEVEL D. SAUVANT Y. CHILLIARD, P. BAS P weight that high levels of milk production are closely associated with an intense mobili- zation of body work was conducted to study the relationships which associate milk yield and lipomobilization levels

Paris-Sud XI, Université de

167

Mercury and mink. I. The use of mercury contaminated fish as a food for ranch mink.  

PubMed Central

Adult female and juvenile ranch mink were fed rations containing 50 and 75% of fish containing 0.44 ppm total mercury over a 145 day period. There was no clinical or pathological evidence of intoxication in these animals and mercury concentrations in tissue appeared to be at a level below that associated with toxicity. PMID:1000375

Wobeser, G; Nielsen, N O; Schiefer

1976-01-01

168

Diabetes alters aromatase enzyme levels in gonadal tissues of rats.  

PubMed

Diabetes mellitus (DM) is associated with increased risk of reproductive problems. Estrogens have important roles in reproductive processes in both genders. Aromatase catalyzes the conversion of androgens to estrogens and is expressed in a variety of tissues. Although it is known that insulin regulate the activity of aromatase, there are few data about the effects of diabetes on this enzyme. The aim of the present study was to investigate the effects of experimental diabetes on aromatase expression levels in ovary, testis, uterus, and vas deferens tissues of female and male rats. Rats were injected with streptozotocin to induce diabetes. At the end of 4 and 12 weeks, tissue homogenates were prepared and evaluated for aromatase proteins by western blot. Uterus and vas deferens smooth muscle responses were also evaluated. Aromatase expression levels in ovary were significantly decreased both in 4 and 12 weeks of diabetes. In testis, enzyme levels were not altered at 4 weeks, but significantly decreased at 12 weeks of diabetes. In uterus and vas deferens tissues, no significant differences were observed at aromatase immunoreactivity but uterus and vas deferens smooth muscle responses were altered. These results indicated for the first time that DM altered the expression levels of aromatase both in ovary and testis but did not affect enzyme levels in uterus and vas deferens tissues. Altered smooth muscle responses did not correlate with tissue aromatase levels. Altogether, these findings lead us to suggest that aromatase might be an important target molecule in sexual dysfunction seen in DM. PMID:20428845

Burul-Bozkurt, N; Pekiner, C; Kelicen, P

2010-07-01

169

Incorporating uncertainty in watershed management decision-making: A mercury TMDL case study  

USGS Publications Warehouse

Water quality impairment due to high mercury fish tissue concentrations and high mercury aqueous concentrations is a widespread problem in several sub-watersheds that are major sources of mercury to the San Francisco Bay. Several mercury Total Maximum Daily Load regulations are currently being developed to address this problem. Decisions about control strategies are being made despite very large uncertainties about current mercury loading behavior, relationships between total mercury loading and methyl mercury formation, and relationships between potential controls and mercury fish tissue levels. To deal with the issues of very large uncertainties, data limitations, knowledge gaps, and very limited State agency resources, this work proposes a decision analytical alternative for mercury TMDL decision support. The proposed probabilistic decision model is Bayesian in nature and is fully compatible with a "learning while doing" adaptive management approach. Strategy evaluation, sensitivity analysis, and information collection prioritization are examples of analyses that can be performed using this approach.

Labiosa, W.; Leckie, J.; Shachter, R.; Freyberg, D.; Rytuba, J.

2005-01-01

170

Historical and Other Patterns of Monomethyl and Inorganic Mercury in the Florida Panther ( Puma concolor coryi )  

Microsoft Academic Search

Since the late 1980s, elevated levels of mercury have been reported in the tissues of the Florida panther ( Puma concolor coryi) from the Florida Everglades. The extent, degree, and length of time of mercury contamination in the Florida panther are unknown. The objective of this study was to determine the historical and other patterns of monomethyl and inorganic mercury

J. Newman; E. Zillioux; E. Rich; L. Liang; C. Newman

2004-01-01

171

Effect of diet on tissue levels of palmitoylethanolamide.  

PubMed

Palmitoylethanolamide (PEA) as well as the other N-acylethanolamines (NAEs), e.g. anandamide, oleoylethanolamide, stearoylethanolamide and linoleoylethanolamide, appear to exist in every mammalian cell at low levels, e.g. a few hundred pmol/g tissue for PEA. Their formation can be stimulated by cellular injury and inflammation. In the brain PEA and other NAEs may have neuroprotective functions. PEA levels in tissues seem hardly to be influenced by variation in intake of dietary fatty acids, except in the small intestine where dietary fat results in decreased levels of PEA and other NAEs. In rat small intestine, PEA, oleoylethanolamide and linoleoylethanolamide have anorectic properties. Of other dietary components, only ethanol is known to influence tissue levels of PEA. Thus, an acute intoxicating dose of ethanol will decrease PEA levels in various areas in the brain of rats. The mechanism behind this effect is not known. PMID:23394522

Hansen, Harald S

2013-02-01

172

Menopause and Blood Mercury Levels: The Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011.  

PubMed

This study aimed to evaluate the association between menopause and blood mercury concentrations in South Korean women. Women aged ?20 years who participated in the Korean National Health and Nutrition Examination Survey 2008-2011 were included in this study. Primary and secondary analyses included women aged ?20 years (n?=?1,642) and 45-55 years (i.e., perimenopausal; n?=?325), respectively. For all analyses, the mercury levels were log-transformed. The linear regression model for mercury levels was adjusted for age, body mass index, household income, menopausal status, hormone replacement therapy, use of oral contraceptives, smoking history, alcohol intake, physical activity, number of pregnancies, serum ferritin levels, and fish consumption. After adjusting for covariates, log-transformed blood mercury levels were significantly lower in women who were menopausal [?-coefficient -0.1488; 95 % confidence interval -0.2586, -0.0389; P?=?0.01) than in those who were premenopausal. A similar relationship was identified in perimenopausal women (?-coefficient -0.1753; 95 % confidence interval -0.3357, -0.015; P?=?0.03). The blood mercury concentration was lower in postmenopausal women than in premenopausal women. There was a significant positive correlation between blood mercury concentrations and both the frequency of alcohol intake and serum ferritin levels. PMID:25382663

Yuk, Jin-Sung; Lee, Jung Hun; Jeon, Jin-Dong; Kim, Tai June; Lee, Myung-Hwa; Park, Won I

2014-12-01

173

Determination of Ultratrace Levels of Mercury in SRM 2781 Domestic Sludge by Combustion RNAA  

SciTech Connect

The domestic sludge SRM 2781 was collected from Denver, Colorado, sewage disposal district 1 (DMSDD) in the early 1990s. The DMSDD calls this material 'domestic' because only light industry is present in this district. The term 'domestic' differs from an 'industrial' label by the amount of heavy industry present in the area. The determination of mercury and other toxic elements in these sludges is important to monitor the sources and pathways of environmental exposure to these materials. Analytical results for the determination of total mercury in SRM 2781, domestic sludge, by radiochemical neutron activation analysis (RNAA) are listed in Table I. These analyses were made to measure the total mercury for use in the certification process of this reference material. The control sample data agreed well with the certified values and confirm the methods, procedures, and corrections used. This RNAA combustion procedure is effective in producing high-quality analytical data at the microgram/kilogram concentration level in both the organic and inorganic matrices of these samples. The procedure has both high sensitivity and freedom from significant reagent blanks when properly performed.

Bruce R. Norman; Donald A. Becker; Richard T. Lostritto

2000-11-12

174

Mercury interferes with endogenous antioxidant levels in Yukon River subsistence-fed sled dogs  

NASA Astrophysics Data System (ADS)

Before adopting modern corn-and-grain-based western processed diets, circumpolar people had a high fat and protein subsistence diet and exhibited a low incidence of obesity, diabetes and cardiovascular disease. Some health benefits are attributable to a subsistence diet that is rich in omega-3 fatty acids and antioxidants. Pollution, both global and local, is a threat to wild foods, as it introduces contaminants into the food system. Northern indigenous people and their sled dogs are exposed to a variety of contaminants, including mercury, that accumulate in the fish and game that they consume. The sled dogs in Alaskan villages are maintained on the same subsistence foods as their human counterparts, primarily salmon, and therefore they can be used as a food systems model for researching the impact of changes in dietary components. In this study, the antioxidant status and mercury levels were measured for village sled dogs along the Yukon River. A reference kennel, maintained on a nutritionally balanced commercial diet, was also measured for comparison. Total antioxidant status was inversely correlated with the external stressor mercury.

Dunlap, Kriya L.; Reynolds, Arleigh J.; Gerlach, S. Craig; Duffy, Lawrence K.

2011-10-01

175

Comparison of total mercury levels in relation to diet and molt for nine species of marine birds  

Microsoft Academic Search

Total mercury (Hg) concentrations were analyzed for tissues of nine species of marine birds from the Quoddy region, New Brunswick, Canada, including cormorants (Phalacrocorax auritus), eiders (Somateria mollissima), guillemots (Cepphus grylle), phalaropes (Phalaropus lobatus), gulls (Larus argentatus, L. Philadelphia), terns (Sterna hirundo, S. paradisaea) and kittiwakes (Rissa tridactyla). There was a progressive decrease in Hg concentration from the innermost to

Birgit M. Braune

1987-01-01

176

Mercury and selenium concentrations in fish, sediments, and water of two northwestern Quebec lakes  

SciTech Connect

Research report:In an effort to learn more about mercury in the aquatic ecosystem and about possible ways to moderate the toxicity of mercury accumulated by aquatic organisms, sediment and water samples from Lake Dufault and Lake Duparquet in the Rouyn-Naranda region of Quebec were analyzed. Both mercury and selenium concentrations in muscle tissue of northern pike (Esox lucius) were determined. Significant differences between the mercury and selenium levels in fish from the two lakes were reported. Fish samples from Lake Dufault had low mercury concentrations but elevated levels of selenium. Fish samples from Lake Duparquet, however, had elevated mercury levels and low selenium levels. Elevated mercury levels were present in sediment samples from both lakes. Mercury and selenium levels in water samples from both lakes were at or below analytical detection limits. (15 references, 3 tables)

Speyer, M.R.

1980-03-01

177

MERCURY IN FISH TISSUE ACROSS THE WESTERN UNITED STATES: IMPLICATIONS OF SELENIUM INTERACTIONS  

EPA Science Inventory

We collected 2,707 fish from 626 stream/river sites in 12 western USA states using a probability design to assess the spatial extent of whole fish mercury (Hg) concentrations. In all large (> 120 mm) fish, total Hg concentrations (mean µg·g-1; SD; n) in both piscivores (0.26...

178

Strong positive associations between seafood, vegetables, and alcohol with blood mercury and urinary arsenic levels in the Korean adult population.  

PubMed

Blood mercury and urinary arsenic levels are more than fivefold greater in the Korean population compared with those of the United States. This may be related to the foods people consumed. Therefore, we examined the associations between food categories and mercury and arsenic exposure in the Korean adult population. Data regarding nutritional, biochemical, and health-related parameters were obtained from a cross-sectional study, the 2008-2009 Korean National Health and Nutrition Examination Survey (3,404 men and women age ? 20 years). The log-transformed blood mercury and urinary arsenic levels were regressed against the frequency tertiles of each food group after covariate adjustment for sex, age, residence area, education level, smoking status, and drinking status using food-frequency data. Blood mercury levels in the high consumption groups compared to the low consumption groups were elevated by about 20 percents with salted fish, shellfish, whitefish, bluefish, and alcohol, and by about 9-14 percents with seaweeds, green vegetables, fruits and tea, whereas rice did not affect blood mercury levels. Urinary arsenic levels were markedly increased with consumption of rice, bluefish, salted fish, shellfish, whitefish, and seaweed, whereas they were moderately increased with consumption of grains, green and white vegetables, fruits, coffee, and alcohol. The remaining food categories tended to lower these levels only minimally. In conclusion, the typical Asian diet, which is high in rice, salted fish, shellfish, vegetables, alcoholic beverages, and tea, may be associated with greater blood mercury and urinary arsenic levels. This study suggests that mercury and arsenic contents should be monitored and controlled in soil and water used for agriculture to decrease health risks from heavy-metal contamination. PMID:23011092

Park, Sunmin; Lee, Byung-Kook

2013-01-01

179

Distribution of mercury in the environment at Almaden, Spain  

SciTech Connect

An ecological survey of the concentration and distribution of mercury in terrestrial and aquatic systems near the mercury mine at Almaden, Spain, was initiated in 1974. Field studies were completed in 1977, and chemical analyses were completed in 1979. Sample collection at Almaden followed a trophic-level approach in which certain compartments were sampled at a given instant in time (fall 1974, fall 1975, spring 1976, fall 1976, spring 1977). Mean total mercury concentration in terrestrial plants (8 taxa combined) ranged from >100 ..mu..g/g within 0.5 km of the mine to 1 ..mu..g/g 20 km distant from the mine. Different plant species had different affinities for mercury, but moss species usually had higher total mercury concentration than vascular plants. Woody plants were lower in mercury concentration than forbs. Total mercury concentration in muscle, brain, kidney, and liver tissue from mice was highest at a station near the stream receiving liquid effluent from the mine (mean total mercury at this station ranging from 0.18 ..mu..g/g in muscle to 4.74 ..mu..g/g in kidney). Approximately 15 to 30% of total mercury in mouse tissue was in the methylated form. Total mercury concentration in muscle tissue from house sparrows varied inversely with distance from the mine, with highest concentrations exceeding 0.1 ..mu..g/g. Approximately 1 to 4% of total mercury in sparrow muscle was in the methylated form.

Hildebrand, S.G.; Huckabee, J.W.; Diaz, F.S.; Janzen, S.A.; Solomon, J.A.; Kumar, K.D.

1980-10-01

180

Mercury and selenium levels in 19 species of saltwater fish from New Jersey as a function of species, size, and season.  

PubMed

There are few data on risks to biota and humans from mercury levels in saltwater fish. This paper examines mercury and selenium levels in muscle of 19 species of fish caught by recreational fisherfolk off the New Jersey shore, as a function of species of fish, size, and season, and risk of mercury to consumers. Average mercury levels ranged from 0.01 ppm (wet weight) (Menhaden Brevoortia tyrannus) to 1.83 ppm (Mako Shark Isurus oxyrinchus). There were four categories of mercury levels: very high (only Mako), high (averaging 0.3-0.5 ppm, 3 species), medium (0.14-0.20 ppm, 10 species), and low (below 0.13 ppm, 5 species). Average selenium levels for the fish species ranged from 0.18 ppm to 0.58 ppm, and had lower variability than mercury (coefficient of variation=38.3 vs 69.1%), consistent with homeostatic regulation of this essential element. The correlation between mercury and selenium was significantly positive for five and negative for two species. Mercury levels showed significant positive correlations with fish size for ten species. Size was the best predictor of mercury levels. Selenium showed no consistent relationship to fish length. Over half of the fish species had some individual fish with mercury levels over 0.3 ppm, and a third had fish with levels over 0.5 ppm, levels that pose a human health risk for high end consumers. Conversely several fish species had no individuals above 0.5 ppm, and few above 0.3 ppm, suggesting that people who eat fish frequently, can reduce their risk from mercury by selecting which species (and which size) to consume. Overall, with the exception of shark, Bluefin Tuna (Thunnus thynnus), Bluefish (Pomatomus saltatrix) and Striped Bass (Morone saxatilis), the species sampled are generally medium to low in mercury concentration. Selenium:mercury molar ratios were generally above 1:1, except for the Mako shark. PMID:21292311

Burger, Joanna; Gochfeld, Michael

2011-03-15

181

Mercury concentrations in water and hybrid striped bass (Morone saxatilis × M. chrysops) muscle tissue samples collected from the Ohio River, USA.  

PubMed

We report on long-term aqueous mercury (Hg) measurements collected at fixed locations along the Ohio River, offer insights into patterns of water and fish tissue Hg levels, and calculate site-specific bioaccumulation factors (BAFs) along an extensive longitudinal basis. We examined the relationship between total recoverable Hg concentrations in water and fish samples collected from 12 locations on the mainstem Ohio River. Water samples were collected on a bimonthly basis from each location over a 6-year period preceding the collection of fish tissue samples. This abundance of data enabled us to calculate the long-term average aqueous Hg concentrations and approximate the lifetime aqueous Hg exposure experienced by fish, enabling the calculation of appropriate BAFs. Hybrid striped bass (HSB; Morone saxatilis × M. chrysops) were collected from the Ohio River, composited (three fish), and analyzed for Hg in muscle tissue from each location. Concentrations ranged from 0.2 to 0.4 mg/kg and 41.7% of all samples collected were higher than the US Environmental Protection Agency regulatory threshold of 0.3 mg Hg/kg wet weight. Hg levels generally increased with fish weight, length, and age. However, Hg concentration in the water was the strongest predictor of tissue concentrations. We found that both water and tissue concentrations increased with drainage area, albeit at different rates. This discrepancy in spatial patterns revealed that the bioaccumulation rate of methylmercury might not be consistent throughout the Ohio River mainstem. BAFs calculated at each location supported this finding, as values decreased with increasing drainage area. Our study serves to fill critical, previously identified data gaps and provides decision-makers with the information necessary to develop more appropriate BAF development and risk-management strategies. PMID:20577729

Emery, Erich B; Spaeth, John P

2011-04-01

182

Glutathione peroxidase response in tissues of rats fed diets containing fish protein concentrate prepared from shark flesh of known mercury and selenium contents  

SciTech Connect

Studies have been reported using experimental animals and synthetic diets containing selenium and mercury compounds to demonstrate detoxification of mercury by selenium. The mechanism of detoxification remains obscure. Most experiments have involved the use of high levels of both elements and relied on the observation of gross symptoms. The measurement of enzyme systems may be useful in detecting effects of mercury at a lower, subclinical level and in elucidating the biochemistry of mercury/selenium interactions. The activity of the selenoenzyme glutathione peroxidase (GSH-Px) in rats is dependent on dietary selenium and attempts have been made to use this enzyme as an indicator of mercury/selenium interactions. The research described in this paper was designed to investigate the effect of mercury, in the form and amounts which occur naturally in seafood, on the availability of selenium at levels approximating the nutritional requirement. In anticipation of mercury lowering the GSH-Px response a range of selenium concentrations was used, from nutritional deficiency to three times the nutritional requirement.

Thrower, S.J. (Commonwealth Scientific and Industrial Research Organization, Hobart, Australia); Andrewartha, K.A.

1981-01-01

183

ORIGINAL PAPER Quantifying mRNA levels across tissue sections  

E-print Network

the need for better measurement capability, in situ PCR was invented in the early 1990s, combiningORIGINAL PAPER Quantifying mRNA levels across tissue sections with 2D-RT-qPCR Michael Armani chain reaction (RT-qPCR). This is complex because these steps are typically performed in three separate

Shapiro, Benjamin

184

Interspecific and locational differences in metal levels in edible fish tissue from Saudi Arabia.  

PubMed

Metal levels in fish have been extensively studied, but little data currently exists for the Middle East. We examined the levels of metals and metalloids (aluminum, arsenic, copper, manganese, selenium, zinc, and mercury) in the flesh of 13 fish species collected from three fishing sites and a local fish market in Jeddah, Saudi Arabia. We tested the following null hypotheses: (1) there are no interspecific differences in metal levels, (2) there are no differences in metal levels in fishes between market and fishing sites, (3) there are no size-related differences in metal levels, and (4) there are no differences in selenium:mercury molar ratio among different fish species. There were significant interspecific differences in concentrations for all metals. There was an order of magnitude difference in the levels of aluminum, arsenic, mercury, manganese, and selenium, indicating wide variation in potential effects on the fish themselves and on their predators. Fishes from Area II, close to a large commercial port, had the highest levels of arsenic, mercury, and selenium, followed by market fishes. Mercury was positively correlated with body size in 6 of the 13 fish species examined. Mercury was correlated positively with arsenic and selenium, but negatively with aluminum, cobalt, copper, manganese, and zinc. Selenium:mercury molar ratios varied significantly among species, with Carangoides bajad, Cephalopholis argus, Variola louti, and Ephinephelus tauvina having ratios below 10:1. These findings can be used in risk assessments, design of mercury reduction plans, development of fish advisories to protect public health, and future management decision-making. PMID:24997870

Burger, Joanna; Gochfeld, Michael; Batang, Zenon; Alikunhi, Nabeel; Al-Jahdali, Ramzi; Al-Jebreen, Dalal; Aziz, Mohammed A M; Al-Suwailem, Abdulaziz

2014-10-01

185

Levels of total mercury in marine organisms from Adriatic Sea, Italy.  

PubMed

The presence of total mercury in fish, crustacean and cephalopod from Adriatic Sea, was investigated. The highest concentrations were observed in decreasing order in: Norway lobster (0.97 +/- 0.24 mg/kg; mean +/- SE), European hake (0.59 +/- 0.14 mg/kg), red mullet (0.48 +/- 0.09 mg/kg), blue whiting (0.38 +/- 0.09 mg/kg), Atlantic mackerel (0.36 +/- 0.08 mg/kg) and European flying squid (0.25 +/- 0.03 mg/kg). A significant difference (p < 0.01) was found between the levels of total mercury in Norway lobster and those detected in all other species. The 25% of all samples exceeded the maximum limit fixed by Commission Regulation (EC) No 1881/2006. The results show that fish and fishery products can exceed the maximum levels and stress the need of more information for consumers in particular for people that eat large amount of fish. PMID:19434348

Perugini, Monia; Visciano, Pierina; Manera, Maurizio; Zaccaroni, Annalisa; Olivieri, Vincenzo; Amorena, Michele

2009-08-01

186

MERGANSER- Predicting Mercury Levels in Fish and Loons in New England Lakes  

EPA Science Inventory

MERGANSER (MERcury Geo-spatial AssesmentS for the New England Region) is an empirical least squares multiple regression model using atmospheric deposition of mercury (Hg) and readily obtainable lake and watershed features to predict fish and common loon Hg (as methyl mercury) in ...

187

Projecting the Population-level Effects of Mercury on the Common Loon in the Northeast  

NASA Astrophysics Data System (ADS)

The Common Loon (Gavia immer) is a top-level predator in aquatic systems and is at risk to mercury contamination. This risk is of particular concern in the Northeast, the region of North America in which loons have the highest mean body concentration of methylmercury (MeHg). We used matrix population models to project the population-level effects of mercury on loons in four states in the Northeast (New York, Vermont, New Hampshire, and Maine) exhibiting different levels of risk to MeHg. Four categories of risk to MeHg (low, moderate, high, and extra high) were established based on MeHg levels observed in loons and associated effects observed at the individual and population levels in the field (e.g., behavior and reproductive success). We parameterized deterministic matrix population models using survival estimates from a 12-year band-resight data set and productivity estimates from a 25-year data set of nesting loon observations in NH. The juvenile loon survival rate was 0.55 (minimum) and 0.63 (maximum) (ages 1-3), and the adult loon survival rate was 0.95 (ages 4-30). The mean age at first reproduction was 7. The mean fertility was 0.26 fledgelings per individual at low to moderate risk; there were 53% fewer fledged young per individual at high to extra high risk. Productivity was weighted by risk for each state. The portion of the breeding population at high to extra high risk was 10% in NY, 15% in VT, 17% in NH, and 28% in ME. We also constructed a stochastic model in which productivity was randomly selected in each time step from the 25 estimates in the NH data set. Model results indicated a negative population growth rate for some states. There was a decreasing trend in population growth rate as the percentage of the loon population at high to extra high risk increased. The stochastic model showed that the population growth rate varied over a range of about 0.05 from year to year, and this range decreased as the percentage of the loon population at high to extra high risk increased. These results suggest that an increase in risk to mercury that effects a change in reproductive success may have a negative population-level effect on loons.

Evers, D. C.; Mitro, M. G.; Gleason, T. R.

2001-05-01

188

A simple spectrophotometric determination of trace level mercury using 1,5-diphenylthiocarbazone solubilized in micelle.  

PubMed

A very simple, ultra-sensitive and fairly selective non-extractive spectrophotmetric method is presented for the rapid determination of mercury(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) as a new micellar spectrophotometric reagent (lambdamax = 490 nm) in a slightly acidic (0.07 - 0.17 M H2SO4) aqueous solution. The presence of a micellar system avoids the previous steps of solvent extraction and reduces the cost, toxicity while enhancing the sensitivity, selectivity and the molar absorptivity. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell's sensitivity were found to be 5.02 x 10(4) L mol(-1) cm(-1) and 10 ng cm(-2) of Hg, respectively. Linear calibration graphs were obtained for 0.05 - 10 mg L(-1) of Hg; the stoichiometric composition of the chelate is 1:2 (Hg:dithizone). The method is characterized by a detection limit of 1 microg L(-1) of Hg. Large excesses of over 60 cations, anions and complexing agents (e.g. EDTA, tartrate, oxalate, citrate, phosphate, thiourea, azide, SCN-) do not interfere in the determination. The method was successfully applied to a number of environmental water samples (potable and polluted), biological samples (human blood and urine; milk and fish) and soils; solutions contained both mercury(I) and mercury(II) as well as complex synthetic mixtures. The method has high precision and accuracy (s = +/-0.01 for 0.1 mg L(-1)). PMID:15913137

Khan, Humaira; Ahmed, M Jamaluddin; Bhanger, M Iqbal

2005-05-01

189

Distribution of mercury in the soft tissues of the blue tilapia Oreochromis aureus (Steindachner) after acute exposure to mercury (II) chloride  

Microsoft Academic Search

Mercury has no known biological functions in the animal body and is described as an ultratrace element (Lall 1989). Consequently, there is no well defined regulatory mechanism present in the animal body and it tends to accumulate readily if available in an animal's environment. Sources of mercury include the chloroalkali industry, the manufacture of electrical equipment, paint, fungicides and dentistry

P. Allen

1994-01-01

190

Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide  

NASA Technical Reports Server (NTRS)

The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

Patterson, James D.; Li, Wei-Gang

1995-01-01

191

Can mercury in fish be reduced by water level management? Evaluating the effects of water level fluctuation on mercury accumulation in yellow perch (Perca flavescens).  

PubMed

Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake's watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of the Rainy-Namakan complex (on the border of the United States and Canada) has been linked to water level (WL) fluctuations, presumably through variation in sediment inundation. As a result, Hg contamination of fish has been linked to international regulations of WL fluctuation. Here we assess the relationship between WL fluctuations and fish Hg content using a 10-year dataset covering six lakes. Within-year WL rise did not appear in strongly supported models of fish Hg, but year-to-year variation in maximum water levels (?maxWL) was positively associated with fish Hg content. This WL effect varied in magnitude among lakes: In Crane Lake, a 1 m increase in ?maxWL from the previous year was associated with a 108 ng increase in fish Hg content (per gram wet weight), while the same WL change in Kabetogama was associated with only a 5 ng increase in fish Hg content. In half the lakes sampled here, effect sizes could not be distinguished from zero. Given the persistent and wide-ranging extent of Hg contamination and the large number of regulated waterways, future research is needed to identify the conditions in which WL fluctuations influence fish Hg content. PMID:25134675

Larson, James H; Maki, Ryan P; Knights, Brent C; Gray, Brian R

2014-10-01

192

Can mercury in fish be reduced by water level management? Evaluating the effects of water level fluctuation on mercury accumulation in yellow perch (Perca flavescens)  

USGS Publications Warehouse

Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake’s watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of the Rainy–Namakan complex (on the border of the United States and Canada) has been linked to water level (WL) fluctuations, presumably through variation in sediment inundation. As a result, Hg contamination of fish has been linked to international regulations of WL fluctuation. Here we assess the relationship between WL fluctuations and fish Hg content using a 10-year dataset covering six lakes. Within-year WL rise did not appear in strongly supported models of fish Hg, but year-to-year variation in maximum water levels (?maxWL) was positively associated with fish Hg content. This WL effect varied in magnitude among lakes: In Crane Lake, a 1 m increase in ?maxWL from the previous year was associated with a 108 ng increase in fish Hg content (per gram wet weight), while the same WL change in Kabetogama was associated with only a 5 ng increase in fish Hg content. In half the lakes sampled here, effect sizes could not be distinguished from zero. Given the persistent and wide-ranging extent of Hg contamination and the large number of regulated waterways, future research is needed to identify the conditions in which WL fluctuations influence fish Hg content.

Larson, James H.; Maki, Ryan P.; Knights, Brent C.; Gray, Brian R.

2014-01-01

193

Prostate cancer outcome and tissue levels of metal ions  

USGS Publications Warehouse

BACKGROUND There are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome. METHODS We obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n = 80). Case-control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se. RESULTS Patients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 ??g/g vs. 111 ??g/g; P = 0.04) and 21% lower zinc (279 ??g/g vs. 346 ??g/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 ??g/g vs. 0.439 ??g/g; 4% higher) and selenium (1.68 ??g/g vs. 1.58 ??g/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively). CONCLUSIONS There is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated. Copyright ?? 2011 Wiley-Liss, Inc.

Sarafanov, A. G.; Todorov, T. I.; Centeno, J. A.; MacIas, V.; Gao, W.; Liang, W. -M.; Beam, C.; Gray, M. A.; Kajdacsy-Balla, A. A.

2011-01-01

194

Posidonia oceanica: a biological indicator of past and present mercury contamination in the mediterranean sea  

Microsoft Academic Search

Concentrations of mercury were measured in various tissues of Posidonia oceanica seagrass at three sites presenting distinct degrees of human activity. The accumulation of mercury differed according to the tissue examined and the level of contamination of the site. Mercury concentrations recorded at Calvi ranged from 10.0ng g?1 dry weight in blades to 30.1ng g?1 in rhizomes, whereas at Marseilles-Cortiou,

Christine Pergent-Martini

1998-01-01

195

Check on level of environmental contamination by mercury and cleanup of Abetina Mining area (Grosseto-Italia)  

SciTech Connect

The purpose of the study was to check on the level of environmental contamination and to design a project for cleaning up the Abetina Mine area at Piancastagnaio (Grosseto, Italy). Contamination of this area had occurred during the mining and treatment of cinnabar (HgS) over a prolonged period. The aim of the project is to remove the sources of contamination or render them harmless. Mining of the Piancastagnaio deposit started in 1840, mercury metal being extracted from the ore by thermal treatment. Together with Spain, Italy was the first country to produce this metal and was the world leader in this field between 1936 and 1943. Though mercury production in the Monte Amiata region of Tuscany ceased in 1974 the ensuing environmental impact is very evident, taking the form of rusty old mining and processing works, plus waste tips which still contain considerable amount of mercury even after the ore had been subject to thermal extraction treatment. The research which has been conducted included mapping the area to identify the main sources of mercury and arsenic pollution, as well as the level of environmental contamination. Mercury and arsenic values in excess of 16,000 and 150 ppm respectively are encountered in the most highly-contaminated places. 11 refs., 6 figs., 2 tabs.

Belardi, G.; Marabini, A.M.; Passariello, B. [Institute for Minerals Treatment, Rome (Italy)] [and others

1996-12-31

196

Levels of chlordane, oxychlordane, and nonachlor in human adipose tissues  

SciTech Connect

Chlordane was used as a termiticide for more than twenty years in Japan. Chlordane is stable in the environment such as sediment and its bioaccumulation in some species of bacteria, freshwater invertebrates, and marine fish is large. Many researches were done to elucidate the levels of chlordane and/or its metabolite oxychlordane in human adipose tissues. A comprehensive review concerning chlordane was recently provided by USEPA. On the other hand, Japan authorities banned the use of chlordane in September 1986. In the last paper, the authors reported that both water and sediment of the rivers around Saga city were slightly contaminated with chlordane. In the present study, they investigated the levels of chlordane, oxychlordane and nonachlor in human adipose tissues.

Hirai, Yukio; Tomokuni, Katsumaro (Saga Medical School (Japan))

1991-08-01

197

Mercury, arsenic and selenium exposure levels in relation to fish consumption in the Mediterranean area.  

PubMed

In order to assess mercury (Hg), selenium (Se) and arsenic (As) exposure in the Mediterranean area, total mercury (THg), monomethylmercury (MeHg), Se and As levels were measured in umbilical cord blood and breast milk from Italian (n=900), Slovenian (n=584), Croatian (n=234) and Greek (n=484) women. THg, MeHg, As, and Se levels were also determined in blood samples of the same mothers from Italy and Croatia. In addition, THg and MeHg were determined in the same women's hair from all the countries involved in this study and As and Se levels were determined in the mother's urine samples from Italy, Croatia and Greece. Besides recording the consumption of other food items, the frequencies of fish consumption were assessed by detailed food frequency questionnaires, since fish represents an important source of Hg, Se and As in humans. The highest levels of THg and As were found in cord blood (Med((THg))=5.8 ng/g; Med((As))=3.3 ng/g) and breast milk (Med((THg))=0.6 ng/g; Med((As))=0.8 ng/g) from Greek women, while the highest Se levels were found in cord blood (Med=113 ng/g) from Italy. Significant linear correlations were found between Hg, Se and As in blood, cord blood and breast milk. In addition, significant relations were found between the frequencies of total fish consumption and biomarkers of As, MeHg and Se exposure, with the strongest Spearman rank coefficients between frequencies of total fish consumption and THg levels in cord blood (r(s)=0.442, p<0.001) or THg levels in hair (r(s)=0.421, p<0.001), and between frequencies of total fish consumption and As levels in cord blood (r(s)=0.350, p<0.001). The differences in Hg and As exposure between countries were probably due to different amounts of fish consumption and the consumption of different species of fish of different origin, while the highest Se levels in women from Italy were probably the consequence of the more frequent consumption of different non specific food items. Moreover, fish consumption, the possible common source of As, Hg and Se intake, could explain the correlations between the elements determined in cord blood, mother's blood or breast milk. PMID:22999706

Miklav?i?, Ana; Casetta, Anica; Snoj Tratnik, Janja; Mazej, Darja; Krsnik, Mladen; Mariuz, Marika; Sofianou, Katia; Spiri?, Zdravko; Barbone, Fabio; Horvat, Milena

2013-01-01

198

Seasonal, locational and size variations in mercury and selenium levels in striped bass (Morone saxatilis) from New Jersey  

PubMed Central

We examined total mercury and selenium levels in muscle of striped bass (Morone saxatilis) collected from 2005 to 2008 from coastal New Jersey. Of primary interest was whether there were differences in mercury and selenium levels as a function of size and location, and whether the legal size limits increased the exposure of bass consumers to mercury. We obtained samples mainly from recreational anglers, but also by seine and trawl. For the entire sample (n = 178 individual fish), the mean (± standard error) for total mercury was 0.39 ± 0.02 ?g/g (= 0.39 ppm, wet weight basis) with a maximum of 1.3 ?g/g (= 1.3 ppm wet weight). Mean selenium level was 0.30 ± 0.01 ?g/g (w/w) with a maximum of 0.9 ?g/g). Angler-caught fish (n = 122) were constrained by legal size limits to exceed 61 cm (24 in.) and averaged 72.6 ± 1.3 cm long; total mercury averaged 0.48 ± 0.021 ?g/g and selenium averaged 0.29 ± 0.01 ?g/g. For comparable sizes, angler-caught fish had significantly higher mercury levels (0.3 vs 0.21 ?g/g) than trawled fish. In both the total and angler-only samples, mercury was strongly correlated with length (Kendall tau = 0.37; p < 0.0001) and weight (0.38; p < 0.0001), but was not correlated with condition or with selenium. In the whole sample and all subsamples, total length yielded the highest r2 (up to 0.42) of any variable for both mercury and selenium concentrations. Trawled fish from Long Branch in August and Sandy Hook in October were the same size (68.9 vs 70.1 cm) and had the same mercury concentrations (0.22 vs 0.21 ppm), but different selenium levels (0.11 vs 0.28 ppm). The seined fish (all from Delaware Bay) had the same mercury concentration as the trawled fish from the Atlantic coast despite being smaller. Angler-caught fish from the North (Sandy Hook) were larger but had significantly lower mercury than fish from the South (mainly Cape May). Selenium levels were high in small fish, low in medium-sized fish, and increased again in larger fish, but overall selenium was correlated with length (tau = 0.14; p = 0.006) and weight (tau = 0.27; p < 0.0001). Length-squared contributed significantly to selenium models, reflecting the non-linear relationship. Inter-year differences were explained partly by differences in sizes. The selenium:mercury molar ratio was below 1:1 in 20% of the fish and 25% of the angler-caught fish. Frequent consumption of large striped bass can result in exposure above the EPA’s reference dose, a problem particularly for fetal development. PMID:22226733

Gochfeld, Michael; Burger, Joanna; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

2014-01-01

199

Mercury and selenium concentrations in fish, sediments, and water of two northwestern Quebec lakes  

SciTech Connect

The results of mercury and selenium analyses conducted on northern pike (Esox lucius) muscle tissue indicate distinct and significant differences between the mercury and selenium levels of fish from two lakes in Quebec. While fish samples from Lake Dufault had very low mercury concentrations, they appeared to have elevated amounts of selenium. Conversely, fish samples originating from Lake Duparquet had elevated mercury concentrations and low selenium levels. In both cases a comparison of means by the Student t test indicated significant (P < 0.01) differences between the mercury and selenium concentrations of fish samples from the two lakes.

Speyer, M.R.

1980-03-01

200

Mercury levels in raccoons (Procyon lotor) from the Warta Mouth National Park, northwestern Poland.  

PubMed

This is the first report on mercury (Hg) levels in the liver, kidney, skeletal muscle, and brain of raccoon in Europe. It studied Hg concentration in 24 raccoons from the Warta Mouth National Park, northwestern Poland by atomic absorption spectroscopy (AAS). The highest total Hg concentrations in the raccoon were found in the liver (maximum, 18.45 mg/kg dry weight), while the lowest in the brain (maximum, 0.49 mg/kg dw). In adult raccoons, Hg concentrations in the liver, kidney, and brain were higher than in immature individuals (p<0.001), while similar in skeletal muscle in both age groups. Our results are consistent with studies by other authors conducted in North America in areas with similar environmental conditions. PMID:24736978

Lanocha, Natalia; Kalisinska, Elzbieta; Kosik-Bogacka, Danuta I; Budis, Halina; Podlasinska, Joanna; Jedrzejewska, Ewa

2014-06-01

201

Glutathione enzyme and selenoprotein polymorphisms associate with mercury biomarker levels in Michigan dental professionals  

Microsoft Academic Search

Mercury is a potent toxicant of concern to both the general public and occupationally exposed workers (e.g., dentists). Recent studies suggest that several genes mediating the toxicokinetics of mercury are polymorphic in humans and may influence inter-individual variability in mercury accumulation. This work hypothesizes that polymorphisms in key glutathione synthesizing enzyme, glutathione s-transferase, and selenoprotein genes underlie inter-individual differences in

Jaclyn M. Goodrich; Yi Wang; Brenda Gillespie; Robert Werner; Alfred Franzblau; Niladri Basu

202

Differential effects of cobalt and mercury on lipid metabolism in the white adipose tissue of high-fat diet-induced obesity mice  

SciTech Connect

Metals and metalloid species are involved in homeostasis in energy systems such as glucose metabolism. Enlarged adipocytes are one of the most important causes of obesity-associated diseases. In this study, we studied the possibility that various metals, namely, CoCl{sub 2}, HgCl{sub 2}, NaAsO{sub 2} and MnCl{sub 2} pose risk to or have beneficial effects on white adipose tissue (WAT). Exposure to the four metals resulted in decreases in WAT weight and the size of enlarged adipocytes in mice fed a high-fat diet (HFD) without changes in liver weight, suggesting that the size and function of adipocytes are sensitive to metals. Repeated administration of CoCl{sub 2} significantly increased serum leptin, adiponectin and high-density lipoprotein (HDL) cholesterol levels and normalized glucose level and adipose cell size in mice fed HFD. In contrast, HgCl{sub 2} treatment significantly decreased serum leptin level with the down-regulation of leptin mRNA expression in WAT and a reduction in adipocyte size. Next, we tried to investigate possible factors that affect adipocyte size. Repeated exposure to HgCl{sub 2} significantly decreased the expression levels of factors upon the regulation of energy such as the PPAR? and PPAR? mRNA expression levels in adipocytes, whereas CoCl{sub 2} had little effect on those genes expressions compared with that in the case of the mice fed HFD with a vehicle. In addition, repeated administration of CoCl{sub 2} enhanced AMPK activation in a dose-dependent manner in the liver, skeletal muscle and WAT; HgCl{sub 2} treatment also enhanced AMPK activation in the liver. Thus, both Co and Hg reduced WAT weight and the size of enlarged adipocytes, possibly mediated by AMKP activation in the mice fed HFD. However, inorganic cobalt may have a preventive role in obesity-related diseases through increased leptin, adiponectin and HDL-cholesterol levels, whereas inorganic mercury may accelerate the development of such diseases. These results may lead to the development of new approaches to establishing the role of metals in adipose tissue of obesity-related diseases. -- Highlights: ? The effects of metals on enlarged white adipose tissue (WAT) were studied. ? As, Hg, Mn and Co ions reduced the size of enlarged adipocytes. ? Co{sup 2+} increased serum leptin and adiponectin levels with AMPK activation in WAT. ? Hg{sup 2+} decreased serum leptin level and leptin mRNA expression in WAT. ? Metal exposure affects the adipocyte size and the function of WAT.

Kawakami, Takashige, E-mail: tkawakami@ph.bunri-u-ac.jp; Hanao, Norihide; Nishiyama, Kaori; Kadota, Yoshito; Inoue, Masahisa; Sato, Masao; Suzuki, Shinya

2012-01-01

203

Using native epiphytic ferns to estimate the atmospheric mercury levels in a small-scale gold mining area of West Java, Indonesia.  

PubMed

Mercury pollution is caused by artisanal and small-scale gold mining (ASGM) operations along the Cikaniki River (West Java, Indonesia). The atmosphere is one of the primary media through which mercury can disperse. In this study, atmospheric mercury levels are estimated using the native epiphytic fern Asplenium nidus complex (A. nidus) as a biomonitor; these estimates shed light on the atmospheric dispersion of mercury released during mining. Samples were collected from 8 sites along the Cikaniki Basin during September-November, 2008 and September-November, 2009. The A. nidus fronds that were attached to tree trunks 1-3m above the ground were collected and measured for total mercury concentration using cold vapor atomic absorption spectrometry (CVAAS) after acid-digestion. The atmospheric mercury was collected using porous gold collectors, and the concentrations were determined using double-amalgam CVAAS. The highest atmospheric mercury concentration, 1.8 × 10(3) ± 1.6 × 10(3) ngm(-3), was observed at the mining hot spot, and the lowest concentration of mercury, 5.6 ± 2.0 ngm(-3), was observed at the remote site from the Cikaniki River in 2009. The mercury concentrations in A. nidus were higher at the mining village (5.4 × 10(3) ± 1.6 × 10(3) ngg(-1)) than at the remote site (70 ± 30 ngg(-1)). The distribution of mercury in A. nidus was similar to that in the atmosphere; a significant correlation was observed between the mercury concentrations in the air and in A. nidus (r=0.895, P<0.001, n=14). The mercury levels in the atmosphere can be estimated from the mercury concentration in A. nidus using a regression equation: log (Hg(A.nidu)/ngg(-1))=0.740 log (Hg(Air)/ngm (-3)) - 1.324. PMID:22595529

Kono, Yuriko; Rahajoe, Joeni S; Hidayati, Nuril; Kodamatani, Hitoshi; Tomiyasu, Takashi

2012-09-01

204

Graphite-furnace atomic absorption method for trace-level determination of total mercury  

SciTech Connect

A method is described to determine mercury in water and urine that employs a carbon-furnace atomizer atomic absorption technique. Findings show that a matrix of 5% nitric acid (HNO/sub 3/) and 0.1% potassium dichromate (K/sub 2/Cr/sub 2/O/sub 7/) stabilize the mercury, allowing a pyrolyzation temperature of up to 300/sup 0/C. In this procedure the mercury is atomized before most of the matrix, thereby minimizing potential interferences. The applicability of this method for the determination of organic mercurials is investigated.

Keller, B.J.; Peden, M.E.; Rattonetti, A.

1984-12-01

205

Tissue-specific response of metallothionein and superoxide dismutase in the clam Mactra veneriformis under sublethal mercury exposure.  

PubMed

To identify the relationship between mercury (Hg) and stress responses in the clam Mactra veneriformis, metallothionein (MT) and superoxide dismutase (SOD) mRNA expression in the digestive gland, gill, and mantle as well as MT protein content and SOD activity in the digestive gland were examined under sublethal Hg exposure at doses of 10, 20, and 40 ?g/L for 21 days. The ranking of the tissues in decreasing order of their basal MvMT and MvSOD mRNA expression is as follows: digestive gland > mantle > gill > adductor muscle > foot and digestive gland > mantle > gill > foot > adductor muscle, respectively. Hg exposure significantly elevated MvMT and MvSOD mRNA transcripts in the digestive gland, gill, and mantle in a tissue-specific way. In the digestive gland, a dose-dependent increase of MvMT and MvSOD mRNA expression, stimulation of MT protein, and alteration of SOD activity were observed under Hg stress. MT protein responded later than MT mRNA to Hg exposure and no clear relationship was found between them, indicating the occurrence of posttranscriptional events. All of the results suggest that MT and SOD cooperate in resisting Hg toxicity and maintaining cellular metabolic homeostasis in M. veneriformis. MT and SOD mRNA expressions have great potential as biomarkers of Hg pollution in the aquatic environment for the studied species. PMID:22678552

Fang, Yan; Yang, Hongsheng; Liu, Baozhong

2012-08-01

206

Influence of water quality on the accumulation of methyl 203mercury in gill tissue of minnow (Phoxinus phoxinus).  

PubMed

Effects of pH and concentrations of Cl and Ca on the uptake of methyl mercury (MeHg) in the gills of the minnow (Phoxinus phoxinus) were studied. Chloride concentration and pH in the water affect the speciation of MeHg. Ca was included because it affects the permeability of the gills and could therefore indirectly affect the amount of MeHg accumulated in the tissue. The species formed differ in hydrophobicity, as reflected in their octanol/water partition coefficients (Pow). Both a reduction in pH and an increase in Cl- concentration increased the Pow of MeHg. Ca had no effect on speciation. The accumulation of MeHg in the gill tissue increased with decreasing pH (from pH 7.0 to pH 3.9). Accumulation also increased as Cl- concentrations were increased from 10(-7) to 10(-1) M at pH 7.0. An increase in Ca concentration did not alter the accumulation of MeHg beyond a decrease in MeHg accumulation as Ca increased from 20 to 50 microM. We conclude that, of the water-quality factors studied, those affecting chemical speciation were most important in determining the MeHg uptake. The Ca concentration appears to be of minor importance. PMID:9440244

Block, M; Pärt, P; Glynn, A W

1997-10-01

207

Recent changes in levels of persistent organochlorines and mercury in eggs of seabirds from the Barents Sea  

Microsoft Academic Search

Eggs of ten seabird species were collected from six regions in North Norway, Svalbard and NW Russia in 1993, and were analyzed for organochlorines (OCs) and mercury. Significant declines in levels of PCBs, p,p?-DDE, HCB, ?-HCH, ?-HCH and oxychlordane were documented in nearly half the data set since a similar study in 1983 in six of the seabird species breeding

R. T. Barrett; J. U. Skaare; G. W. Gabrielsen

1996-01-01

208

Assessment of Mercury Levels in Soils, Waters, Bottom Sediments and Fishes of Acre State in Brazilian Amazon  

Microsoft Academic Search

Mercury in the aquatic biota and geologic materials in areas without anthropogenic sources has been stimulating the discussion about the possibility of natural Hg occurrence in the Amazon region. In this study the dispersion of Hg in different geologic materials as well as its relationship with high Hg levels, detected in some species of carnivorous fish consumed in the Rio

E. S. Brabo; R. S. Angélica; A. P. Silva; K. R. F. Faial; A. F. S. Mascarenhas; E. C. O. Santos; I. M. Jesus; E. C. B. Loureiro

2003-01-01

209

Behavior of mercury in bio-systems. II. Depuration of /sup 203/Hg/sup 2 +/ in various trophic levels  

SciTech Connect

Using radiotracer techniques, the depuration rates for methylmercury at three trophic levels in an aquatic ecosystem are examined. Bacteria (decomposers), mosquito larvae (primary consumers), and fish (secondary consumers) were studied. Results indicated that depuration rates for mercury were temperature dependent - the rate of depuration increased with increase in temperature (up to 45/sup 0/C)

Hamdy, M.K.; Prabhu, N.V.

1984-01-01

210

POPULATION-LEVEL RESPONSE OF THE COMMON LOON TO MERCURY IN TWO CANADIAN PROVINCES: A MATRIX MODELING APPROACH  

EPA Science Inventory

We used data collected from Common Loon Gavia immer populations in two Canadian provinces to demonstrate a matrix population modeling approach for evaluating population-level responses to stressors and to understand how these populations may have responded to mercury contaminatio...

211

Low Level Laser Therapy: laser radiation absorption in biological tissues  

NASA Astrophysics Data System (ADS)

In this paper we report the results of an experimental study in which we have measured the transmitted laser radiation through dead biological tissues of various animals (chicken, adult and young bovine, pig) in order to evaluate the maximum thickness through which the power density could still produce a reparative cellular effect. In our experiments we have utilized a pulsed laser IRL1 ISO model (based on an infrared diode GaAs, ?=904 nm) produced by BIOMEDICA s.r.l. commonly used in Low Level Laser Therapy. Some of the laser characteristics have been accurately studied and reported in this paper. The transmission results suggest that even with tissue thicknesses of several centimeters the power density is still sufficient to produce a cell reparative effect.

Di Giacomo, Paola; Orlando, Stefano; Dell'Ariccia, Marco; Brandimarte, Bruno

2013-07-01

212

Relating land cover characteristics and common loon mercury levels using geographic information systems.  

PubMed

This effort models the relationship between mercury (Hg) levels in the common loon (Gavia immer) and land cover types as defined by the National Land Cover Database (NLCD). We constructed the model within the framework of a GIS to analyze the spatial relationships between land cover types and blood Hg levels in male common loons. Thiessan polygons were used to generate the territory for each loon. We created 150, 300, and 600-m buffers around the Thiessan polygons and modeled the relationships that existed in each distance class. Within the 150-m buffer, three cover types, crop land, shrub land, and wetland were significantly related to blood Hg levels (r2 = 0.552, p < 0.001), which may indicate that the proximity of these cover types influences Hg availability in loon territories. Cropland exhibited a negative relationship with blood Hg levels and may play a role in reducing the amount of available Hg within the study area while wetlands and shrub lands exhibit a positive relationship. The study area consisted of five major lakes and eleven smaller ponds in northwest Maine, and data included a total of 61 male common loon blood Hg samples. PMID:15931970

Kramar, David; Goodale, Wing M; Kennedy, L M; Carstensen, L W; Kaur, Taranjit

2005-03-01

213

The Influence of Fish Length on Tissue Mercury Dynamics: Implications for Natural Resource Management and Human Health Risk  

PubMed Central

Consumption of fish has well-known human health benefits, though some fish may contain elevated levels of mercury (Hg) that are especially harmful to developing children. Fish length is most often the basis for establishing fishery harvest regulations that determine which fish will ultimately be consumed by humans. It is, therefore, essential to quantify the relationship between fish length and Hg accumulation in regard to harvest regulations for effective fishery and public health policy. We examined this relationship for three sportfish from six lakes across North Carolina, USA. Bluegill (Lepomis macrochirus) had the lowest Hg levels and only the very largest fish in the most contaminated site exceeded the US Environmental Protection Agency (USEPA) Hg screening level. Black crappie (Pomoxis nigromaculatus) had an intermediate level of Hg and larger individuals exceeded the USEPA screening level; however, they tended not to exceed this level before reaching the harvest length limit. Largemouth bass (Micropterus salmoides) exceeded the USEPA screening level at sizes below the fishery length limit in two lakes, leaving only higher risk fish for anglers to harvest and consume. Removing the effects of fish age and trophic position, we found strong positive correlations between Hg and fish length for largemouth bass and black crappie. We suggest public health officials and wildlife managers collaborate to structure fishery regulations and length-based fish consumption advisories that protect consumers from Hg exposure and communicate the relative risk of fish consumption. PMID:23388852

Sackett, Dana K.; Cope, W. Gregory; Rice, James A.; Aday, D. Derek

2013-01-01

214

Acute effects of mercuric chloride on intracellular GSH levels and mercury distribution in the fish Oreochromic aureus  

SciTech Connect

In recent years there has been much interest in the effects of trace metals on intracellular levels of reduced glutathione (GSH). Most of the research has been performed on rats. As GSH is ubiquitous in living organisms it is of interest to establish a relationship between mercury intoxication and intracellular GSH levels in fish; especially as fish living in rivers and coastal areas are often expose to mercury as an aquatic pollutant. The role of GSH in fish trace metal toxicity has not been thoroughly investigated. The distribution of total glutathione (oxidized + reduced) in selected black sea bass organs seems to follow the established pattern for mammalian organs. Thus, it would appear that teleostian and mammalian glutathione metabolism may have many similarities. There are few reports concerning the effects of mercury during the first few hours of exposure. The aim of this investigation is to establish any changes in organ GSH and mercury levels following just 2 h exposure to mercuric chloride (HgCl/sub 2/).

Allen, P.; Min, S.Y.; Keong, W.M.

1988-02-01

215

Mercury Levels in Mink ( Mustela vison ) and River Otter ( Lontra canadensis ) from Northeastern North America  

Microsoft Academic Search

Aquatic ecosystems have received mercury released from anthropogenic sources. The northeast region of North America is at especially high risk because of local and regional emission sources, prevailing wind patterns, and certain hydrological and biogeochemical features. Here we examine regional variation in total mercury (Hg) in brain, liver, and fur from otter and mink collected across New York, New England,

David E. Yates; David T. Mayack; Kenneth Munney; David C. Evers; Andrew Major; Taranjit Kaur; Robert J. Taylor

2005-01-01

216

Increased tissue kallikrein levels in type 2 diabetes  

Microsoft Academic Search

Aims\\/hypothesis  We measured components of the kallikrein–kinin system in human type 2 diabetes mellitus and the effects of statin therapy\\u000a on the circulating kallikrein–kinin system.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Circulating levels of bradykinin and kallidin peptides, and high and low molecular weight kininogens, as well as plasma and\\u000a tissue kallikrein, and kallistatin were measured in non-diabetic and diabetic patients before coronary artery bypass graft\\u000a surgery.

D. J. Campbell; A. Kladis; Y. Zhang; A. J. Jenkins; D. L. Prior; M. Yii; J. F. Kenny; M. J. Black; D. J. Kelly

2010-01-01

217

Relationship between blood mercury levels and components of male song in Nelson's sparrows (Ammodramus nelsoni).  

PubMed

Mercury (Hg) adversely affects the health and behavior of exposed wildlife; however, behavioral effects remain largely unknown. Changes in avian singing behavior may affect a male's fitness because song reveals male quality and thus influences female mate choice and male territory-holding ability. Nelson's sparrows (Ammodramus nelsoni) live exclusively on salt marshes and risk high levels of Hg exposure and bioaccumulation. We recorded songs of male Nelson's sparrows at two locations with different Hg exposure to determine if total blood Hg concentration was related to song characteristics, as previously reported for other species. Males with higher blood Hg levels sang at higher maximum tonal frequency, but blood Hg and site location did not influence low tonal frequency and bout duration, contrary to predictions based on other species. Within the contaminated site, Hg levels were related to bouts per minute and gap duration, such that males at that site sang faster songs. Hg influences hormones and alters brain development, raising questions about specific effects on the brains and singing behavior of male Nelson's sparrows. PMID:22945769

McKay, Jennifer L; Maher, Christine R

2012-11-01

218

Environmental levels of cadmium, lead and mercury in brown hares and their relation to blood metabolic parameters.  

PubMed

The purpose of this study was to examine concentrations of selected heavy metals in the liver and kidney of brown hares (Lepus europaeus). In addition, correlations between heavy metals and biochemical parameters in blood plasma were determined. The average concentrations of heavy metals (mmol/L) +/- SD were as follows: liver: Pb 0.221 +/- 0.189, Cd 0.160 +/- 0.140, Hg 0.021 +/- 0.030, kidney: Pb 0.115 +/- 0.125, Cd 1.570 +/- 1.103, Hg 0.030 +/- 0.053. The average concentrations of biochemical parameters in the blood plasma were as follows: Ca 3.16 mmol/L, P 2.19 mmol/L, Mg 1.40 mmol/L, Na 148.71 mmol/L, K 8.12 mmol/L, glucose 6.56 mmol/L, total proteins 56.49 g/L, urea 5.00 mmol/L, total lipids 1.40 g/L, bilirubin 3.97 micro mol/L, cholesterol 1.53 mmol/L, aspartate aminotransferase (AST) 6.06 micro kat/L and alanine aminotransferase (ALT) 1.94 micro kat/L. Average levels of hormones (ng/mL) were as follows: testosterone 2.94, androstendiol 0.13, estradiol 501.59, progesterone 6.63, oxytocin 328.60. Tissue analysis showed an accumulation of lead, cadmium and mercury in the liver and kidney of brown hares. There were no significant correlations between levels of heavy metals in liver, kidney, and biochemical parameters. PMID:18393073

Kolesarova, Adriana; Slamecka, Jaroslav; Jurcik, Rastislav; Tataruch, Frieda; Lukac, Norbert; Kovacik, Jaroslav; Capcarova, Marcela; Valent, Miroslav; Massanyi, Peter

2008-05-01

219

Development and test application of a screening-level mercury fate model and tool for evaluating wildlife exposure risk for surface waters with mercury-contaminated sediments (SERAFM)  

Microsoft Academic Search

Complex chemical cycling of mercury in aquatic ecosystems means that tracing the linkage between anthropogenic and natural loadings of mercury to watersheds and water bodies and associated concentrations in the environment are difficult to establish without the assistance of numerical models that describe biogeochemical controls on mercury distribution and availability to organisms. This paper presents an overview of a process-based,

Christopher D. Knightes

2008-01-01

220

Hair mercury and urinary cadmium levels in Belgian children and their mothers within the framework of the COPHES/DEMOCOPHES projects.  

PubMed

A harmonized human biomonitoring pilot study was set up within the frame of the European projects DEMOCOPHES and COPHES. In 17 European countries, biomarkers of some environmental pollutants, including urinary cadmium and hair mercury, were measured in children and their mothers in order to obtain European-wide comparison values on these chemicals. The Belgian participant population consisted in 129 school children (6-11 years) and their mothers (? 45 years) living in urban or rural areas of Belgium. The geometric mean levels for mercury in hair were 0.383 ?g/g and 0.204 ?g/g for respectively mothers and children. Cadmium in mother's and children's urine was detected at a geometric mean concentration of respectively 0.21 and 0.04 ?g/l. For both biomarkers, levels measured in the mothers and their child were correlated. While the urinary cadmium levels increased with age, no trend was found for hair mercury content, except the fact that mothers hold higher levels than children. The hair mercury content increased significantly with the number of dental amalgam fillings, explaining partially the higher levels in the mothers by their higher presence rate of these amalgams compared to children. Fish or seafood consumption was the other main parameter determining the mercury levels in hair. No relationship was found between smoking status and cadmium or mercury levels, but the studied population included very few smokers. Urinary cadmium levels were higher in both mothers and children living in urban areas, while for mercury this difference was only significant for children. Our small population showed urinary cadmium and hair mercury levels lower than the health based guidelines suggested by the WHO or the JECFA (Joint FAO/WHO Expert Committee on Food Additives). Only 1% had cadmium level slightly higher than the German HBM-I value (1 ?g/l for adults), and 9% exceeded the 1 ?g mercury/g hair suggested by the US EPA. PMID:24333995

Pirard, Catherine; Koppen, Gudrun; De Cremer, Koen; Van Overmeire, Ilse; Govarts, Eva; Dewolf, Marie-Christine; Van De Mieroop, Els; Aerts, Dominique; Biot, Pierre; Casteleyn, Ludwine; Kolossa-Gehring, Marike; Schwedler, Gerda; Angerer, Jürgen; Koch, Holger M; Schindler, Birgit K; Castaño, Argelia; Esteban, Marta; Schoeters, Greet; Den Hond, Elly; Sepai, Ovnair; Exley, Karen; Horvat, Milena; Bloemen, Louis; Knudsen, Lisbeth E; Joas, Reinhard; Joas, Anke; Van Loco, Joris; Charlier, Corinne

2014-02-15

221

Establishment of a primary hepatocyte culture from the small Indian mongoose (Herpestes auropunctatus) and distribution of mercury in liver tissue.  

PubMed

The present study established a primary hepatocyte culture for the small Indian mongoose (Herpestes auropunctatus). To determine the suitable medium for growing the primary hepatic cells of this species, we compared the condition of cells cultured in three media that are frequently used for mammalian cell culture: Dulbecco's Modified Eagle's Medium, RPMI-1640, and William's E. Of these, William's E medium was best suited for culturing the hepatic cells of this species. Using periodic acid-Schiff staining and ultrastructural observations, we demonstrated the cells collected from mongoose livers were hepatocytes. To evaluate the distribution of mercury (Hg) in the liver tissue, we carried out autometallography staining. Most of the Hg compounds were found in the central region of hepatic lobules. Smooth endoplasmic reticulum, which plays a role inxenobiotic metabolism, lipid/cholesterol metabolism, and the digestion and detoxification of lipophilic substances is grown in this area. This suggested that Hg colocalized with smooth endoplasmic reticulum. The results of the present study could be useful to identify the detoxification systems of wildlife with high Hg content in the body, and to evaluate the susceptibility of wildlife to Hg toxicity. PMID:25142347

Horai, Sawako; Yanagi, Kumiko; Kaname, Tadashi; Yamamoto, Masatatsu; Watanabe, Izumi; Ogura, Go; Abe, Shintaro; Tanabe, Shinsuke; Furukawa, Tatsuhiko

2014-11-01

222

Linking Atmospheric Mercury Deposition to Human and Wildlife (Source to Receptor) by Coupling VELMA and WASP with BASS to simulate Fish Tissue Mercury Concentrations  

EPA Science Inventory

Mercury (Hg) is the toxicant responsible for the majority of fish advisories across the United States, with 1.25 million miles of rivers under advisory due to the exposure risk from ingesting Hg-contaminated fish. The processes governing Hg exposures in lotic ecosystems are not...

223

Bioaccumulation of Mercury in Sharks  

E-print Network

Bioaccumulation of Mercury in Sharks Part 1 b After you finish the video and the above questions by humans) sources. 2. How does mercury travel from its source into the tissue of sharks? 3. What are some

Miami, University of

224

Elevated circulating levels of tissue factor in polycystic ovary syndrome.  

PubMed

Women with polycystic ovary syndrome (PCOS) have coagulation disturbances and inflammation, which increases the risk of atherothrombosis. We evaluated the status of circulating tissue factor (TF), the receptor for coagulation factor VII involved in atherothrombosis, in women with PCOS and weight-matched controls. Two-way analysis of variance models were fit to evaluate the effect of PCOS status and weight class on TF and other parameters. The TF levels were significantly higher in lean women with PCOS compared to lean controls. Plasminogen activator inhibitor 1 (PAI-1) levels were significantly higher in obese participants compared to lean participants after controlling for PCOS status. The TF levels directly correlated with percentage of truncal fat and plasma levels of PAI-1, testosterone, androstendione, and dehydroepiandrosterone-sulfate; and inversely correlated with insulin sensitivity index-OGTT(IS(OGTT)). Circulating TF is elevated in PCOS independent of obesity, but both PCOS and obesity contribute to a prothrombotic state. In PCOS, abdominal adiposity and hyperandrogenism may exacerbate the risk of atherothrombosis. PMID:22327820

González, Frank; Kirwan, John P; Rote, Neal S; Minium, Judi

2013-01-01

225

Heavy metal concentrations in feathers of common loons (Gavia immer) in the Northeastern United States and age differences in mercury levels.  

PubMed

Feathers serve as a useful, non-destructive approach for biomonitoring some aspects of environmental quality. Birds can eliminate over 90% of their body burden of mercury by sequestration in growing feathers, and they molt their feathers at least annually. Thus mercury concentrations should not vary in avian feathers as a function of age. We tested the null hypothesis that there are no age differences in the concentrations of mercury, lead, cadmium, selenium, copper, chromium and manganese in the feathers of immature and adult common loons Gavia immer from the Northeastern United States where the species is declining. Adults had significantly higher mean levels of mercury (20245 ppb) than immature loons (9677 ppb), but there were no age-related differences for other elements. Even with the small number of immatures, females had significantly higher levels of mercury than males, although the gender difference was not significant for adults. PMID:24213705

Burger, J; Pokras, M; Chafel, R; Gochfeld, M

1994-03-01

226

The processing of simulated high-level radioactive waste sludges containing nitrites and mercury  

SciTech Connect

The reaction of formic acid with simulated alkaline sludge containing mercury and nitrite was studied in an engineering-scale facility. Quantification of offgas production was performed, with the major offgases being CO{sub 2} and NO{sub x}. A small amount of CO was also found. The NO{sub x} was scrubbed in the offgas condenser and formed very acidic solutions of nitrous and nitric acids. These acids dissolved mercury that was stripped from the sludge. However, the overall efficiency of mercury stripping was greater than expected, and the final mercury concentration in the sludge was lower than expected. The NO{sub x} in the offgas also caused large temperature rises in the offgas system due to the exothermic reaction of NO with O{sub 2}. This temperature rise had a detrimental effect on the performance of the Formic Acid Vent Condenser, such that redesign is being contemplated. 6 refs., 6 figs., 3 tabs.

Zamecnik, J.R.; Hutson, N.D.; Ritter, J.A.; Carter, J.T.

1991-01-01

227

Linking cellulose fiber sediment methyl mercury levels to organic matter decay and major element composition.  

PubMed

Methylation of mercury (Hg) to highly toxic methyl Hg (MeHg), a process known to occur when organic matter (OM) decomposition leads to anoxia, is considered a worldwide threat to aquatic ecosystems and human health. We measured temporal and spatial variations in sediment MeHg, total Hg (THg), and major elements in a freshwater lagoon in Sweden polluted with Hg-laden cellulose fibers. Fiber decomposition, confined to a narrow surface layer, resulted in loss of carbon (C), uptake of nitrogen (N), phosphorus (P), and sulfur (S), and increased MeHg levels. Notably, fiber decomposition and subsequent erosion of fiber residues will cause buried contaminants to gradually come closer to the sediment-water interface. At an adjacent site where decomposed fiber accumulated, there was a gain in C and a loss of S when MeHg increased. As evidenced by correlation patterns and vertical chemical profiles, reduced S may have fueled C-fixation and Hg methylation at this site. PMID:24420263

Regnell, Olof; Elert, Mark; Höglund, Lars Olof; Falk, Anna Helena; Svensson, Anders

2014-11-01

228

Inter- and intraclutch variation in egg mercury levels in marine bird species from the Canadian Arctic.  

PubMed

Mercury (Hg) is a toxic metal that has been of increasing concern in the Canadian Arctic. We measured total Hg in eggs of three marine birds (Arctic terns Sterna paradisaea, common eiders Somateria mollissima borealis, long-tailed ducks Clangula hyemalis) that breed in the Canadian Arctic, to compare Hg laying order effects from the same clutch and to examine Hg among species. Early-laid eggs of all three species had 24-48% higher Hg concentrations than late laid eggs. Arctic terns had approximately twice the concentration of Hg in their eggs as the two duck species, and Hg in eider eggs from the High Arctic was higher than Hg in eggs from the Low Arctic. Higher Hg in tern eggs was consistent with this species occupying a higher trophic position in marine food webs, as indicated by stable nitrogen isotope (delta(15)N) values. The egg-laying sequence may need to be considered for Hg biomonitoring studies where small samples sizes are planned, and early eggs may be preferable for such studies since early eggs may be more representative of potential maximum levels of Hg in the marine food webs. PMID:19962722

Akearok, Jason A; Hebert, Craig E; Braune, Birgit M; Mallory, Mark L

2010-01-15

229

Phytoremediation of Ionic and Methyl Mercury Pollution  

SciTech Connect

Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to control the chemical speciation, electrochemical state, transport, and aboveground binding of mercury in order to manage this toxicant. To advance this mercury phytoremediation strategy, our planned research focuses on the following Specific Aims: (1) to increase the transport of mercury to aboveground tissue; (2) to identify small mercury binding peptides that enhance hyperaccumulation aboveground; (3) to test the ability of multiple genes acting together to enhance resistance and hyperaccumulation; (4) to construct a simple molecular system for creating male/female sterility, allowing engineered grass, shrub, and tree species to be released indefinitely at contaminated sites; (5) to test the ability of transgenic cottonwood and rice plants to detoxify ionic mercury and prevent methylmercury release from contaminated sediment; and (6) to initiate field testing with transgenic cottonwood and rice for the remediation of methylmercury and ionic mercury. The results of these experiments will enable the phytoremediation of methyl- and ionic mercury by a wide spectrum of deep-rooted, fast-growing plants adapted to diverse environments. We have made significant progress on all six of these specific aims as summarized below.

Meagher, Richard B.

2005-06-01

230

Cattle egret ( Bubulcus ibis ) and Little egret ( Egretta garzetta ) as monitors of mercury contamination in Shadegan Wetlands of south-western Iran  

Microsoft Academic Search

Mercury concentrations in feather, liver, kidney, and muscle tissue of Little egret (n?=?8) and Cattle egret (n?=?3) from Shadegan Wetlands in south-western Iran were examined. Liver of Little egret had significantly higher mercury compared\\u000a to Cattle egret (p?mercury values were consistently larger in Little egret when compared to Cattle egret, but mercury\\u000a levels found in feather, kidney,

Rasool Zamani-Ahmadmahmoodi; Abbas Esmaili-Sari; Mozhgan Savabieasfahani; Nader Bahramifar

2010-01-01

231

Relationship between mercury accumulation in young-of-the-year yellow perch and water-level fluctuations  

USGS Publications Warehouse

A three-year (2001 -2003) monitoring effort of 14 northeastern Minnesota lakes was conducted to document relationships between water-level fluctuations and mercury bioaccumulation in young-of-the-year (YOY) yellow perch (Perca flavescens) collected in the fall of each year at fixed locations. Six of those lakes are located within or adjacent to Voyageurs National Park and are influenced by dams on the outlets of Rainy and Namakan lakes. One site on Sand Point Lake coincides with a location that has nine years of previous monitoring suitable for addressing the same issue over a longer time frame. Mean mercury concentrations in YOY yellow perch at each sampling location varied significantly from year to year. For the 12-year monitoring site on Sand Point Lake, values ranged from 38 ng gww-1 in 1998 to 200 ng gww -1 in 2001. For the 14-lake study, annual mean concentrations ranged by nearly a factor of 2, on average, for each lake over the three years of record. One likely factor responsible for these wide variations is that annual water-level fluctuations are strongly correlated with mercury levels in YOY perch for both data sets. ?? 2005 American Chemical Society.

Sorensen, J. A.; Kallemeyn, L. W.; Sydor, M.

2005-01-01

232

Effects of reservoir drawdown and refill on mercury levels in fish and other biota  

SciTech Connect

Mercury bioavailability from contaminated sediments is controlled by methylation, related to bacterial activity and degradable organic material. These variables may be affected by large changes in water level and chemistry in a reservoir. At Par Pond, a 1,200 ha impoundment on the USDOE Savannah River Site, South Carolina, potential failure of an earthen dam prompted lowering the reservoir by 3 meters over a two month period in 1991, decreasing water volume about 70%. The reservoir was refilled over a two month period in 1995. Largemouth bass (Micropterus salmoides) were sampled at quarterly intervals before, during and after the drawdown. Length and weight were determined, and liver and muscle analyzed for total Hg. Hg was also measured in top level predators (alligators), forage fish, macrophytes and invertebrates. From Fall 1991 Winter 1994--5, Hg ranged from 0.05 to 2.0 ug/g wet mass in bass muscle, and was strongly related to fish size, based on about 400 fish. Condition factor rose soon after drawdown, then declined as forage populations collapsed. Using fish size as covariate, bass muscle Hg was greater in spring 1992 than all other sampling dates. However, after 3 years of drawdown, there was no overall trend in bass Hg. Forage species differed in Hg, with highest concentrations in brook silversides (0.13 {micro}g Hg/g wet mass in 2 g fish). Alligators contained up to 20 {micro}g Hg/g dry mass in liver. Refill caused inundation of terrestrial plants on exposed sediments, and microbial action associated with the decay of these may enhance Hg methylation. Experiments with caged fish are underway to measure uptake rates.

Jagoe, C.H.; Salice, C.; Yabnochko, G.; Grasman, B.T.; Youngblood, T. [Savannah River Ecology Lab., Aiken, SC (United States)

1995-12-31

233

Concentrations of 17 elements, including mercury, in the tissues, food and abiotic environment of Arctic shorebirds  

Microsoft Academic Search

Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates

Anna L. Hargreaves; Douglas P. Whiteside; Grant Gilchrist

2011-01-01

234

Mercury study report to Congress. Volume 6. Characterization of human health and wildlife risks from anthropogenic mercury emissions in the United States. Sab review draft  

SciTech Connect

The volume of the draft Mercury Study Report to Congress characterizes risk for mercury emitted to the environment from anthropogenic sources. The characterization volume describes human and wildlife health effects of mercury exposure with accompanying analysis of uncertainty in quantitative risk estimates. Exposure pathways for selected human and wildlife populations to mercury are considered, again accompanied by a discussion of uncertainty. The size of the fish-eating U.S. population and quantities of mercury consumed in fish are estimated, as are the number of maternal-fetal pairs for whom maternal fish consumption is projected to exceed levels identified to be of concern. Literature reports of mercury concentrations in tissues of fish-eating wildlife species are presented. The sizes of selected wildlife populations identified as potentially exposed to quantities of methylmercury associated with adverse health effects are estimated. An overall characterization of risk of mercury to human subpopulations and selected fish-consuming wildlife species is developed.

Mahaffey, K.R.; Schoeny, R.; Rice, G.E.; Keating, M.H.

1996-06-01

235

Concentrations of 17 elements, including mercury, in the tissues, food and abiotic environment of Arctic shorebirds.  

PubMed

Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates and shorebird blood to assess evidence for bioconcentration and biomagnification within the Arctic-based food chain. We tested whether elements in blood, feathers and eggs of six shorebird species (Pluvialis squatarola, Calidris alpina, C. fuscicollis, Phalaropus fulicarius, Charadrius semipalmatus, and Arenaria interpres) were related to fitness endpoints: adult body condition, blood-parasite load, egg size, eggshell thickness, nest duration, and hatching success. To facilitate comparison to other sites, we summarise the published data on toxic metals in shorebird blood and egg contents. Element concentrations and invertebrate composition differed strongly among habitats, and habitat use and element concentrations differed among shorebird species. Hg, Se, Cd, Cu, and Zn bioconcentrated from soil to invertebrates, and Hg, Se and Fe biomagnified from invertebrates to shorebird blood. As, Ni, Pb, Co and Mn showed significant biodilution from soil to invertebrates to shorebirds. Soil element levels were within Canadian guidelines, and invertebrate Hg levels were below dietary levels suggested for the protection of wildlife. However, maximum Hg in blood and eggs approached levels associated with toxicological effects and Hg-pollution in other bird species. Parental blood-Hg was negatively related to egg volume, although the relationship varied among species. No other elements approached established toxicological thresholds. In conclusion, whereas we found little evidence that exposure to elements at this site is leading to the declines of the species studied, Hg, as found elsewhere in the Canadian Arctic, is of potential concern for breeding bird populations. PMID:21762958

Hargreaves, Anna L; Whiteside, Douglas P; Gilchrist, Grant

2011-09-01

236

MERCURY IN THE ENVIRONMENT  

EPA Science Inventory

Mercury is released from a variety of sources and exhibits a complicated chemistry. According to the Mercury Study Report to Congress, mercury fluxes and budgets in water, soil, and other media have increased by a factor of two to five over pre-industrial levels. The primary expo...

237

Assessment of total and organic mercury levels in blue sharks (Prionace glauca) from the south and southeastern Brazilian coast.  

PubMed

Mercury occurrence was evaluated in samples of edible muscle tissue of 27 blue sharks (Prionace glauca) caught in the Atlantic Ocean, adjacent to the south and southeastern Brazilian coast, indicating a slight increase in comparison with previous data obtained for the same studied area and being higher than those fish caught at different sites of the Atlantic Ocean. Total Hg concentrations ranged from 0.46 to 2.40 mg kg(-1) with the organic Hg fraction ranging between 0.44 and 2.37 mg kg(-1). A negative correlation between total Hg concentration in muscle tissue and blue shark size was obtained, and 40% of samples analyzed had Hg concentrations higher than 1.0 mg kg(-1) Hg, the maximum concentration permitted in Brazilian predator fish. Data obtained showed that total Hg can be used as a reliable predictor of organic Hg in blue shark muscle because 95 to 98% of the total Hg measured was found to be organic mercury. The wide range of Hg concentrations obtained for our set of samples can be explained by the heterogeneity of sampled population and the large size of the studied area. Given the adverse toxicological effects of Hg on animals and humans, a regular monitoring program of Hg contamination in Brazilian marine ecosystem can be recommended. PMID:24801656

de Carvalho, Gabriel Gustinelli Arantes; Degaspari, Iracema Alves Manoel; Branco, Vasco; Canário, João; de Amorim, Alberto Ferreira; Kennedy, Valerie Helen; Ferreira, José Roberto

2014-06-01

238

Biomagnification of Mercury and Selenium in Blue Shark Prionace glauca from the Pacific Ocean off Mexico  

Microsoft Academic Search

The aim of this study was to determine the biomagnification of mercury through the principal prey of the blue shark, Prionace glauca, off the western coast of Baja California Sur, Mexico, as well as the relationship between mercury and selenium in blue sharks.\\u000a High levels of mercury were found in shark muscle tissues (1.39?±?1.58 ?g\\/g wet weight); these values are above

Ofelia Escobar-Sánchez; Felipe Galván-Magaña; René Rosíles-Martínez

239

Mercury concentrations in the Australian fur seal Arctocephalus pusillus from SE Australian waters  

SciTech Connect

Marine carnivores such as seals and sea lions occupy an important position in the upper trophic level of the marine food web and this, together with their longevity, makes these marine mammals useful indicators of mercury accumulation in the marine environment. Little information exists on mercury concentrations in marine mammals from the southern hemisphere. This paper reports total mercury concentrations in the tissues of the Australian Fur Seal Arctocephalus pusillus from southeastern Australian waters.

Bacher, G.J.

1985-10-01

240

CORRELATION OF DNA METHYLATION WITH MERCURY CONTAMINATION IN MARINE ORGANISMS: A CASE STUDY OF NOAA MUSSEL WATCH TISSUE SAMPLES  

E-print Network

American oysters (Crassostrea virginica) obtained from the NOAA Mussel Watch program were screened for DNA methylation, a type of epigenetic response to stressors. Oysters were collected from sites in the Gulf of Mexico having high mercury...

Brinkmeyer, Robin; Taylor, Robert; Germ, Kaylyn E.

2011-08-04

241

Correlates between feeding ecology and mercury levels in historical and modern arctic foxes (Vulpes lagopus).  

PubMed

Changes in concentration of pollutants and pathogen distribution can vary among ecotypes (e.g. marine versus terrestrial food resources). This may have important implications for the animals that reside within them. We examined 1) canid pathogen presence in an endangered arctic fox (Vulpes lagopus) population and 2) relative total mercury (THg) level as a function of ecotype ('coastal' or 'inland') for arctic foxes to test whether the presence of pathogens or heavy metal concentration correlate with population health. The Bering Sea populations on Bering and Mednyi Islands were compared to Icelandic arctic fox populations with respect to inland and coastal ecotypes. Serological and DNA based pathogen screening techniques were used to examine arctic foxes for pathogens. THg was measured by atomic absorption spectrometry from hair samples of historical and modern collected arctic foxes and samples from their prey species (hair and internal organs). Presence of pathogens did not correlate with population decline from Mednyi Island. However, THg concentration correlated strongly with ecotype and was reflected in the THg concentrations detected in available food sources in each ecotype. The highest concentration of THg was found in ecotypes where foxes depended on marine vertebrates for food. Exclusively inland ecotypes had low THg concentrations. The results suggest that absolute exposure to heavy metals may be less important than the feeding ecology and feeding opportunities of top predators such as arctic foxes which may in turn influence population health and stability. A higher risk to wildlife of heavy metal exposure correlates with feeding strategies that rely primarily on a marine based diet. PMID:23671561

Bocharova, Natalia; Treu, Gabriele; Czirják, Gábor Árpád; Krone, Oliver; Stefanski, Volker; Wibbelt, Gudrun; Unnsteinsdóttir, Ester Rut; Hersteinsson, Páll; Schares, Gereon; Doronina, Lilia; Goltsman, Mikhail; Greenwood, Alex D

2013-01-01

242

Correlates between Feeding Ecology and Mercury Levels in Historical and Modern Arctic Foxes (Vulpes lagopus)  

PubMed Central

Changes in concentration of pollutants and pathogen distribution can vary among ecotypes (e.g. marine versus terrestrial food resources). This may have important implications for the animals that reside within them. We examined 1) canid pathogen presence in an endangered arctic fox (Vulpes lagopus) population and 2) relative total mercury (THg) level as a function of ecotype (‘coastal’ or ‘inland’) for arctic foxes to test whether the presence of pathogens or heavy metal concentration correlate with population health. The Bering Sea populations on Bering and Mednyi Islands were compared to Icelandic arctic fox populations with respect to inland and coastal ecotypes. Serological and DNA based pathogen screening techniques were used to examine arctic foxes for pathogens. THg was measured by atomic absorption spectrometry from hair samples of historical and modern collected arctic foxes and samples from their prey species (hair and internal organs). Presence of pathogens did not correlate with population decline from Mednyi Island. However, THg concentration correlated strongly with ecotype and was reflected in the THg concentrations detected in available food sources in each ecotype. The highest concentration of THg was found in ecotypes where foxes depended on marine vertebrates for food. Exclusively inland ecotypes had low THg concentrations. The results suggest that absolute exposure to heavy metals may be less important than the feeding ecology and feeding opportunities of top predators such as arctic foxes which may in turn influence population health and stability. A higher risk to wildlife of heavy metal exposure correlates with feeding strategies that rely primarily on a marine based diet. PMID:23671561

Krone, Oliver; Stefanski, Volker; Wibbelt, Gudrun; Unnsteinsdottir, Ester Rut; Hersteinsson, Pall; Schares, Gereon; Doronina, Lilia; Goltsman, Mikhail; Greenwood, Alex D.

2013-01-01

243

Levels of Persistent Organic Pollutant Residues in Human Adipose and Muscle Tissues in Singapore  

Microsoft Academic Search

Persistent organic pollutants (POPs), due to their persistence and bioconcentration in lipid-rich tissue, bioaccumulate in food chains, resulting in elevated concentrations in humans. This study was performed to determine and compare levels of POPs in human adipose and muscle tissues in the female population of Singapore. In total, 36 human adipose tissues and 8 human muscle tissues were collected from

Qing Qing Li; Annamalai Loganath; Yap Seng Chong; Jing Tan; Jeffrey Philip Obbard

2006-01-01

244

Species- and size-specific variability of mercury concentrations in four commercially important finfish and their prey from the northwest Atlantic.  

PubMed

Total mercury was analyzed as a function of body length, season, and diet in four commercially and recreationally important marine fish, bluefish (Pomatomus saltatrix), goosefish (Lophius americanus), silver hake (Merluccius bilinearis), and summer flounder (Paralichthys dentatus), collected from continental shelf waters of the northwest Atlantic Ocean. Mercury levels in the dorsal muscle tissue of 115 individuals ranged from 0.006 to 1.217 ?g/g (wet weight) and varied significantly among species. The relationship between predator length and mercury concentration was linear for bluefish and summer flounder, while mercury levels increased with size at an exponential rate for silver hake and goosefish. Mercury burdens were the highest overall in bluefish, but increased with size at the greatest rate in silver hake. Seasonal differences were detected for bluefish and goosefish with mercury levels peaking during summer and spring, respectively. Prey mercury burdens and predator foraging habits are discussed as the primary factors influencing mercury accumulation. PMID:21310437

Staudinger, Michelle D

2011-04-01

245

Chlorinated hydrocarbon and mercury levels in bald eagles (Haliaeetus leucocephalus) found dead in British Columbia, 1988--1993  

SciTech Connect

Liver samples from 70 bald eagles found dead or dying in British Columbia between 1988 and 1993 were analyzed for organochlorine and mercury levels. A subset of 11 eagles found around the Strait of Georgia, an area of known pulp mill pollution, in summer (and therefore presumably resident birds) were analyzed for polychlorinated dibenzo-p-dioxins (PCDDS) and polychlorinated dibenzofurans (PCDFs). Levels of DDE and PCBs ranged from less than 1 mg/kg to 190 and 65 mg/kg respectively. Levels of other organochlorines were generally less than 1 mg/kg, with the exception of some chlordane-related compounds which were occasionally over 2 mg/kg. All birds analyzed for PCDDs/PCDFs contained detectable levels of the major 2,378-substituted isomers. Some birds had extremely high levels, one eagle collected near a kraft pulp mill site contained: 400 ng/kg 2378-TCDD, 1400 ng/kg 12378-PnCDD and 4400 ng/kg 123678-HxCDD. All but two eagles had > 1 mg/kg dry wt. of mercury in liver; most contained less than 1 0 mg/kg d.w. but one bird had 130 mg/kg, a level of toxicological concern. All carcasses were autopsied and cause of death determined wherever possible. The relationship between cause of death and sublethal exposure to OCs and Hg is analyzed and discussed.

Elliott, J.E.; Wilson, L.K. [Canadian Wildlife Service, Delta, British Columbia (Canada); Norstrom, R.J. [Canadian Wildlife Service, Ottawa, Ontario (Canada); Langelier, K.M. [Island Veterinary Hospital, Nanaimo, British Columbia (Canada)

1994-12-31

246

Ecological and physiological parameters of mercury and cesium-137 accumulation in the raccoon  

SciTech Connect

Raccoons from 4 regions in the southeastern Coastal Plain were evaluated for mercury content. Mercury content of hair when used as an indicator of total body mercury content was significantly different among 3 of the 4 areas: Okefenokee Swamp, Eglin Air Force Base, and Sapelo Island on the Georgia Coast. Raccoons from Echols County Georgia were not significantly different from those of the Okefenokee. Mercury in the liver and kidney was significantly different between Okefenokee and Sapelo. There was a strong correlation between the age of the raccoon and the mercury in hair, with older animals having higher concentrations. This relationship was also valid for most other tissues. There was evidence that mercury content in some tissues was correlated with the season and the body condition of the raccoon. Mercury was not transferred through the placenta to the fetal raccoons. There was a strong relationship of mercury content to raccoon behavioral characteristics. Raccoon body weight was slightly different between the areas studied. Cesium-137 values in raccoons were significantly different between the Okefenokee and Sapelo Island. Cesium-137 content was correlated with raccoon age, body weight, and mercury content. Generally non-detectable levels of chlorinated hydrocarbons and PCB were found in Okefenokee raccoons. Mercury concentrations in crayfish were generally low but probably of importance in the raccoon food chain. The biological half life of mercury in brain, gonad, pancreas, spleen, heart, and lung was approximately 52 days. The half-life of mercury in muscle was 35 days. Mercury content of hair, liver, and kidney decreased at very slow rates, with biological half lives of 229, 108, and 138 days. This was probably due to the role of these tissues in clearance of mercury from the body, and to the molting pattern of raccoon hair.

Davis, A.H.

1981-01-01

247

Measurement of cesium and mercury emissions from the vitrification of simulated high level radioactive waste  

SciTech Connect

In the Defense Waste Processing Facility at the Savannah River Site, it is desired to measure non-radioactive cesium in the offgas system from the glass melter. From a pilot scale melter system, offgas particulate samples were taken on filter paper media and analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The ICP-MS method proved to be sufficiently sensitive to measure cesium quantities as low as 0.135 {mu}g, with the sensitivity being limited by the background cesium present in the filter paper. This sensitivity allowed determination of cesium decontamination factors for four of the five major components of the offgas system. In addition, total particulate measurements were also made. Measurements of mercury decontamination factors were made on the same equipment; the results indicate that most of the mercury in the offgas system probably exists as elemental mercury and HgCl{sub 2}, with some HgO and Hg{sub 2}Cl{sub 2}. The decontamination factors determined for cesium, total particulate, and mercury all compared favorably with the design values.

Zamecnik, J.R.

1992-12-31

248

Inter and intraclutch variation in egg mercury levels in marine bird species from the Canadian Arctic  

Microsoft Academic Search

Mercury (Hg) is a toxic metal that has been of increasing concern in the Canadian Arctic. We measured total Hg in eggs of three marine birds (Arctic terns Sterna paradisaea, common eiders Somateria mollissima borealis, long-tailed ducks Clangula hyemalis) that breed in the Canadian Arctic, to compare Hg laying order effects from the same clutch and to examine Hg among

Jason A. Akearok; Craig E. Hebert; Birgit M. Braune; Mark L. Mallory

2010-01-01

249

Cytogenetic damage related to low levels of methyl mercury contamination in the Brazilian Amazon  

E-print Network

, Mitotic Index, Cytogenetics. INTRODUCTION Since the late seventies extensive gold mining op- erations, from mining operations and lixiviation of soils after deforesta- tion, is considered to be the main clinical signs and symptoms of mercury poisoning occur. The first apparent biological effect

Long, Bernard

250

Tissue dependent variations of DNA methylation and endoreduplication levels during tomato fruit development and ripening  

Microsoft Academic Search

Tomato fruit cells are characterized by a strong increase in nuclear ploidy during fruit development. Average ploidy levels\\u000a increased to similar levels (above 50C) in two distinct fruit tissues, pericarp and locular tissue. However, ploidy profiles\\u000a differed significantly between these two tissues suggesting a tissue-specific control of endoreduplication in tomato fruit.\\u000a To determine possible relationships between endoreduplication and epigenetic mechanisms,

E. Teyssier; G. Bernacchia; S. Maury; A. How Kit; L. Stammitti-Bert; D. Rolin; P. Gallusci

2008-01-01

251

DIETARY METHYL MERCURY EXPOSURE IN AMERICAN KESTRELS; PILOT STUDY  

EPA Science Inventory

Anthropogenic mercury emissions have increased atmospheric mercury levels about threefold since the advent of industrial activity. Atmospheric deposition is the primary source of mercury in the environment hence mercury contamination has increased in similar fashion. Methyl mercu...

252

Increased peroxisome proliferator?activated receptor ? expression levels in visceral adipose tissue, and serum CCL2 and interleukin-6 levels during visceral adipose tissue accumulation.  

PubMed

This study was conducted to determine the mRNA and protein expression levels of peroxisome proliferator?activated receptors (PPARs) in visceral adipose tissue, as well as serum adipokine levels, in Sprague Dawley rats. The rats were fed either a normal (control rats) or excessive (experimental rats) intake of food for 8 or 16 weeks, then sacrificed, at which time visceral and subcutaneous adipose tissues, as well as blood samples, were collected. The mRNA and protein expression levels of PPARs in the visceral adipose tissues were determined using reverse transcription-polymerase chain reaction and Western blotting, respectively. In addition, the levels of adipokines in the serum samples were determined using commercial ELISA kits. The results revealed that at 8 weeks, the mass of subcutaneous adipose tissue was higher than that of the visceral adipose tissue in the experimental rats, but the reverse occurred at 16 weeks. Furthermore, at 16 weeks the experimental rats exhibited an upregulation of PPAR? mRNA and protein expression levels in the visceral adipose tissues, and significant increases in the serum levels of CCL2 and interleukin (IL)-6 were observed, compared with those measured at 8 weeks. In conclusion, this study demonstrated that the PPAR? expression level was likely correlated with serum levels of CCL2 and IL-6, molecules that may facilitate visceral adipose tissue accumulation. In addition, the levels of the two adipokines in the serum may be useful as surrogate biomarkers for the expression levels of PPAR? in accumulated visceral adipose tissues. PMID:25324014

Yogarajah, Thaneswary; Bee, Yvonne-Tee Get; Noordin, Rahmah; Yin, Khoo Boon

2015-01-01

253

Mercury Calculator  

NSDL National Science Digital Library

This interactive calculator produced by Teachers' Domain helps you determine the mercury levels in various types of fish, and enables you to make more informed choices about which fish are safe to eat and which should be avoided or eaten infrequently.

Foundation, Wgbh E.

2010-12-23

254

Cadmium and mercury accumulation in European hare (Lepus europaeus): age-dependent relationships in renal and hepatic tissue.  

PubMed

A total of 63 European hares have been collected from five Serbian agricultural regions. The hares assayed were divided into four age groups (3-6 months, 12 months, 12-24 months, and 24-36 months) and investigated upon presence at cadmium (Cd) and mercury (Hg) in the kidney and liver. The positive significant correlation (Ps-Pearson's coefficient) between Cd concentrations in the kidney and liver within age group the 3-6 months was found (Ps?=?0.81, p?levels in the kidney were not significant between presented age groups (p?>?0.05). Statistically significant differences were registered between Hg content in the liver of the hares aged 24-36 and 12 months (p??0.05). The strong statistically significant associations were registered between Cd and Hg content in the liver (Cd L/Hg L) in the age group 3-6 and 12-24 months (Cd L/Hg L, Ps?=?0.94; p?

Petrovi?, Zoran; Teodorovi?, Vlado; Djuri?, Spomenka; Mili?evi?, Dragan; Vrani?, Danijela; Luki?, Mirjana

2014-12-01

255

Mercury exposure, serum antinuclear/antinucleolar antibodies, and serum cytokine levels in mining populations in Amazonian Brazil: a cross-sectional study.  

PubMed

Mercury is an immunotoxic substance that has been shown to induce autoimmune disease in rodent models, characterized by lymphoproliferation, overproduction of immunoglobulin (IgG and IgE), and high circulating levels of auto-antibodies directed at antigens located in the nucleus (antinuclear auto-antibodies, or ANA) or the nucleolus (antinucleolar auto-antibodies, or ANoA). We have reported elevated levels of ANA and ANoA in human populations exposed to mercury in artisanal gold mining, though other confounding variables that may also modulate ANA/ANoA levels were not well controlled. The goal of this study is to specifically test whether occupational and environmental conditions (other than mercury exposure) that are associated with artisanal gold mining affect the prevalence of markers of autoimmune dysfunction. We measured ANA, ANoA, and cytokine concentrations in serum and compared results from mercury-exposed artisanal gold miners to those from diamond and emerald miners working under similar conditions and with similar socio-economic status and risks of infectious disease. Mercury-exposed gold miners had higher prevalence of detectable ANA and ANoA and higher titers of ANA and ANoA as compared to diamond and emerald miners with no occupational mercury exposure. Also, mercury-exposed gold miners with detectable ANA or ANoA in serum had significantly higher concentrations of pro-inflammatory cytokines IL-1beta, TNF-alpha, and IFN-gamma in serum as compared to the diamond and emerald miners. This study provides further evidence that mercury exposure may lead to autoimmune dysfunction and systemic inflammation in affected populations. PMID:20176347

Gardner, Renee M; Nyland, Jennifer F; Silva, Ines A; Ventura, Ana Maria; de Souza, Jose Maria; Silbergeld, Ellen K

2010-05-01

256

MERCURY DEPOSITION AND LAKE QUALITY TRENDS  

EPA Science Inventory

Watershed factors influence the differing trends in mercury residue levels. Fish mercury concentrations show positive correlations with water color, methylmercury concentrations, and plankton mercury, and negative correlations with pH and alkalinity....

257

Mercury levels of Nelson’s and saltmarsh sparrows at wintering grounds in Virginia, USA  

Microsoft Academic Search

Nelson’s and saltmarsh sparrows (Ammodramus nelsoni and A. caudacutus) have recently been recognized as separate species, and because of their limited distributions and the susceptibility of\\u000a their wetland habitats to climate change, these two new species are of conservation concern. Both species are known to bioaccumulate\\u000a mercury at breeding sites in New England, USA where their ranges overlap, with the

Daniel A. CristolFletcher; Fletcher M. Smith; Claire W. Varian-Ramos; Bryan D. Watts

258

Interrelationships between mercury levels in yearling yellow perch, fish condition and water quality  

Microsoft Academic Search

Yearling yellow perch were collected from sixteen Muskoka-Haliburton lakes to determine interrelationships between water quality, Hg residues in fish and fish condition. The lakes studied were Precambrian shield lakes with a pH range of 5.6 to 7.3 and total inflection point alkalinities of 0.4 to 16.0 mg L-1. Mercury residues in yellow perch ranged from 31 to 233 ng g-1

K. Suns; G. Hitchin

1990-01-01

259

Temporal Trends in Beluga, Narwhal and Walrus Mercury Levels: Links to Climate Change  

Microsoft Academic Search

\\u000a The exposure of Arctic marine mammals to contaminants may change via ecological dynamics in response to climate change. For\\u000a example, changes to the structure of the food web or shifts in regional foraging could affect dietary exposure. We examined\\u000a the temporal variation of total mercury (THg) concentrations in Hudson Bay beluga (Delphinapterus leucas) and Foxe Basin walrus (Odobenus rosmarus rosmarus)

A. Gaden; G. A. Stern

260

Multiscale mechanobiology: mechanics at the molecular, cellular, and tissue levels  

PubMed Central

Mechanical force is present in all aspects of living systems. It affects the conformation of molecules, the shape of cells, and the morphology of tissues. All of these are crucial in architecture-dependent biological functions. Nanoscience of advanced materials has provided knowledge and techniques that can be used to understand how mechanical force is involved in biological systems, as well as to open new avenues to tailor-made bio-mimetic materials with desirable properties. In this article, we describe models and show examples of how force is involved in molecular functioning, cell shape patterning, and tissue morphology. PMID:23731596

2013-01-01

261

How do tissues respond to damage at the cellular level? The role of cytokines in irradiated tissues  

NASA Technical Reports Server (NTRS)

The capacity of ionizing radiation to affect tissue function, control tumor growth and elicit pathological sequelae has been attributed in great part to its effects on cellular DNA, which, as the transmitter of genetic information, can both register damage and perpetuate it. Nonetheless, multicellular organisms function as the result of the cooperation of many cell types. What then occurs when individual cells are damaged by ionizing radiation? Is tissue response a sum of cellular effects such as cell death and DNA damage? Or does the tissue respond as a coherent unit to the damage of its parts? In this paper, data in support of the latter model that indicate a role for cytokines, in particular transforming growth factor beta1, as critical components of extracellular signaling pathways that mediate tissue response to radiation will be reviewed. The key to manipulating the consequences of radiation exposure lies in understanding the complex interplay of events initiated at the cellular level, but acting on the tissue.

Barcellos-Hoff, M. H.; Chatterjee, A. (Principal Investigator)

1998-01-01

262

Residue levels of polychlorobiphenyls, ?DDT, and mercury in bird species commonly preyed upon by the peregrine falcon ( Falco peregrinus Tunst.) in Sweden  

Microsoft Academic Search

The levels of polychlorobiphenyls (PCBs), SDDT, and total mercury were analyzed in samples of common prey species of the peregrine falcon in two falcon territories, one in northern and one in southern Sweden. Resident and herbivorous prey species showed low residue levels, while elevated levels were found in birds feeding on animals in aquatic habitats. According to biomass, waders accounted

Peter Lindberg; Tjelvar Odsjö; Lars Reutergftrdh

1985-01-01

263

High levels of maternally transferred mercury do not affect reproductive output or embryonic survival of northern watersnakes (Nerodia sipedon).  

PubMed

Maternal transfer is an important exposure pathway for contaminants because it can directly influence offspring development. Few studies have examined maternal transfer of contaminants, such as mercury (Hg), in snakes, despite their abundance and high trophic position in many ecosystems where Hg is prevalent. The objectives of the present study were to determine if Hg is maternally transferred in northern watersnakes (Nerodia sipedon) and to evaluate the effects of maternal Hg on reproduction. The authors captured gravid female watersnakes (n?=?31) along the South River in Waynesboro, Virginia, USA, where an extensive Hg-contamination gradient exists. The authors measured maternal tissue and litter Hg concentrations and, following birth, assessed (1) reproductive parameters (i.e., litter size and mass, neonate mass); (2) rates of infertility, death during development, stillbirths, malformations, and runts; and (3) the overall viability of offspring. Mercury concentrations in females were strongly and positively correlated with concentrations in litters, suggesting that N. sipedon maternally transfer Hg in proportion to their tissue residues. Maternal transfer resulted in high concentrations (up to 10.10?mg/kg dry wt total Hg) of Hg in offspring. The authors found little evidence of adverse effects of Hg on these measures of reproductive output and embryonic survival, suggesting that N. sipedon may be more tolerant of Hg than other vertebrate species. Given that this is the first study to examine the effects of maternally transferred contaminants in snakes and that the authors did not measure all reproductive endpoints, further research is needed to better understand factors that influence maternal transfer and associated sublethal effects on offspring. PMID:23233365

Chin, Stephanie Y; Willson, John D; Cristol, Daniel A; Drewett, David V V; Hopkins, William A

2013-03-01

264

Accumulation of mercury in the tissues of the common octopus Octopus vulgaris (L.) in two localities on the Portuguese coast  

E-print Network

1932 and 1968 (Smith and Smith, 1975). Mercury is rare in the earth's crust, being present for human consumption. D 2004 Elsevier B.V. All rights reserved. Keywords: Toxic element; Marine pollution/or anthropogenic sources--or from air deposition (NAS, 2000). Although most indications are that atmospheric

Pierce, Graham

265

Accumulation of mercury in the tissues of the common octopus Octopus vulgaris (L.) in two localities on the Portuguese coast  

E-print Network

(Japan) between 1932 and 1968 (Smith and Smith, 1975). Mercury is rare in the earth's crust, being within the range of values legally defined as safe for human consumption. Keywords: Toxic element; Marine/or anthropogenic sources--or from air deposition (NAS, 2000). Although most indications are that atmospheric

Paris-Sud XI, Université de

266

Temporal trend of mercury in polar bears (Ursus maritimus) from4 Svalbard using teeth as a biomonitoring tissue5  

E-print Network

1 1 2 3 Temporal trend of mercury in polar bears (Ursus maritimus) from4 Svalbard using teeth and carbon stable isotopes in teeth of polar bear29 (Ursus maritimus) from Svalbard as biotracers of temporal changes in Hg pollution exposure30 between 1964 and 2003. Teeth were regarded as a good matrix of the Hg

Paris-Sud XI, Université de

267

Mecury in Fin Clips and Scales as Assessment Methods for Predicting Muscle Tissue Mercury Concentrations in Red Drum and Snook  

EPA Science Inventory

Non-lethal techniques for assessing total mercury concentrations in fish are desired because they minimize impacts on fish populations and allow trends in Hg accumulation to be assessed through repeated sampling of individual fish. This study developed relationships of Hg concent...

268

MERCURY LEVELS IN FISH FROM THE UPPER PENINSULA OF MICHIGAN (ELS SUBREGION 2B) IN RELATION TO LAKE ACIDITY  

EPA Science Inventory

The accumulation of mercury by fish and the potential human health effects of eating mercury-contaminated fish have been well documented. owever, elevated mercury concentrations in fish from dilute, low-pH lakes have only recently been associated with increased lake acidity. ever...

269

A novel tissue model for angiogenesis: evaluation of inhibitors or promoters in tissue level  

PubMed Central

A novel tissue model for angiogenesis (TMA) is established for effective evaluation of angiogenesis inhibitors or promoters in vitro. Lung tissues were cultured in fibrinogen “sandwich” structure which resembled the formation of neovessels in vivo. The cells and capillary-like structures grew from the lung tissues were identified as endothelial cells and neovessels. Both immunohistochemisty and western blot results indicated that autocrine VEGF bound to the KDR and induced KDR autophosphorylation that could induce the proliferation of endothelial cells and their migration as well as the formation of microvessels on the lung tissue edge. With addition of the TMA, the murine VEGF and cultured medium produced by A549 tumor cells apparently promoted the increase of neovessels. Sorafenib as a tumor angiogenesis inhibitor and Tongxinluo as an angiogenesis promoter were both used to evaluate the TMA performance and they exhibited a good effect on neovessels in the TMA. The model established imitated angiogenesis in vivo and could well serve as an effective method in evaluating the angiogenesis inhibitors or promoters, and could also be practical for screening small molecules that affect blood vessel formation. PMID:24424154

Dai, Bingling; Zhang, Yanmin; Zhan, Yingzhuan; Zhang, Dongdong; Wang, Nan; He, Langchong

2014-01-01

270

Temporal trends (1989–2011) in levels of mercury and other heavy metals in feathers of fledgling great egrets nesting in Barnegat Bay, NJ  

SciTech Connect

There is an abundance of data for levels of metals from a range of species, but relatively few long-term time series from the same location. In this paper I examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers from fledgling great egrets (Ardea alba) collected at nesting colonies in Barnegat Bay, New Jersey from 1989 to 2011. The primary objectives were to test the null hypotheses that (1) There were no temporal differences in metal levels in feathers of fledgling great egrets, and (2) Great egrets nesting in different areas of Barnegat Bay (New Jersey) did not differ in metal levels. There were significant yearly variations in levels of all heavy metals in feathers of fledgling great egret, but levels decreased significantly from 1989 to 2011 only for lead (1470 ppb to 54.3 ppb), cadmium (277 ppb to 30.5 ppb), and manganese (only since 1996; 2669 ppb to 329 ppb)). Although mercury levels decreased from 2003–2008 (6430 ppb to 1042 ppb), there was no pattern before 2003, and levels increased after 2008 to 2610 ppb in 2011. Lead, cadmium, chromium, manganese and mercury were higher in feathers from great egrets nesting in the northern part of the bay, and selenium was highest in feathers from mid-bay. The lack of a temporal decline in mercury levels in feathers of great egrets is cause for concern, since the high levels in feathers from some years (means as high as 6430 ppb) are in the range associated with adverse effects (5000 ppb for feathers). -- Highlights: ? Metals were monitored in feathers of great egrets from Barnegat Bay, New Jersey. ? Levels of cadmium and lead decreased significantly from 1989–2011. ? Mercury levels in feathers from great egrets did not decline from 1989–2011. ? Metal levels were generally higher in great egrets and black-crowned night heron feathers than in snowy egrets.

Burger, Joanna, E-mail: burger@biology.rutgers.edu [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey 08854-8082, USA and also with Environmental and Occupational Health Sciences Institute (EOHSI), Piscataway, New Jersey (United States)] [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey 08854-8082, USA and also with Environmental and Occupational Health Sciences Institute (EOHSI), Piscataway, New Jersey (United States)

2013-04-15

271

Mercury Speciation in Fish Tissues from a Mediterranean River Basin: The Tagus River (Central Spain) as a Case Study  

Microsoft Academic Search

An assessment of mercury (Hg) accumulation in fish from the Tagus River aquatic system (central Spain), which has been influenced\\u000a by pollution from industrial and urban development, was performed. Total Hg (THg), inorganic Hg (IHg), and monomethylmercury\\u000a (MMHg) were determined in muscle and liver of different fish species, including Cyprinus carpio, Ameiurus melas, and Chondrostoma miegii, sampled from three locations.

J. J. Berzas Nevado; R. C. Rodríguez Martín-Doimeadios; F. J. Guzmán Bernardo; M. Jiménez Moreno; M. J. Patiño Ropero; A. de Marcos Serrano

272

Trace level voltammetric determination of heavy metals and total mercury in tea matrices (Camellia sinensis).  

PubMed

An analytical procedure regarding the voltammetric determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) by square wave anodic stripping voltammetry (SWASV) in matrices involved in food chain is proposed. In particular, tea leaves were analyzed as real samples. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 acidic attack mixture; 0.01 mol L(-1) EDTA-Na2+ 0.15 mol L(-1) NaCl + 0.5 mol L(-1) HCl was employed as the supporting electrolyte. The voltammetric measurements were carried out using a conventional three electrode cell, employing, as working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode (HMDE). The analytical procedure has been verified on the standard reference materials Spinach Leaves NIST-SRM 1570a, Tomato Leaves NIST-SRM 1573a and Apple Leaves NIST-SRM 1515. For all the elements, the precision as repeatability, expressed as relative standard deviation (sr) was of the order of 3-5%, while the trueness, expressed as relative error (e) was of the order of 3-7%. Once set up on the standard reference materials, the analytical procedure was applied to commercial tea leaves samples. A critical comparison with spectroscopic measurements is also discussed. PMID:24416778

Melucci, Dora; Locatelli, Marcello; Locatelli, Clinio

2013-12-01

273

Phytoremediation of Ionic and Methyl Mercury P  

SciTech Connect

Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and/or sequester toxic heavy metal pollutants as an environmentally friendly alternative to physical remediation methods. We have focused this phytoremediation research on soil and water-borne ionic and methylmercury. Mercury pollution is a serious world-wide problem affecting the health of human and wild-life populations. Methylmercury, produced by native bacteria at mercury-contaminated wetland sites, is a particularly serious problem due to its extreme toxicity and efficient biomagnification in the food chain. We engineered several plant species (e.g., Arabidopsis, tobacco, canola, yellow poplar, rice) to express the bacterial genes, merB and/or merA, under the control of plant regulatory sequences. These transgenic plants acquired remarkable properties for mercury remediation. (1) Transgenic plants expressing merB (organomercury lyase) extract methylmercury from their growth substrate and degrade it to less toxic ionic mercury. They grow on concentrations of methylmercury that kill normal plants and accumulate low levels of ionic mercury. (2) Transgenic plants expressing merA (mercuric ion reductase) extract and electrochemically reduce toxic, reactive ionic mercury to much less toxic and volatile metallic mercury. This metal transformation is driven by the powerful photosynthetic reducing capacity of higher plants that generates excess NADPH using solar energy. MerA plants grow vigorously on levels of ionic mercury that kill control plants. Plants expressing both merB and merA degrade high levels of methylmercury and volatilize metallic mercury. These properties were shown to be genetically stable for several generations in the two plant species examined. Our work demonstrates that native trees, shrubs, and grasses can be engineered to remediate the most abundant toxic mercury pollutants. Building on these data our working hypothesis for the next grant period is that transgenic plants expressing the bacterial merB and merA genes will (a) remove mercury from polluted soil and water and (b) prevent methylmercury from entering the food chain. Our specific aims center on understanding the mechanisms by which plants process the various forms of mercury and volatilize or transpire mercury vapor. This information will allow us to improve the design of our current phytoremediation strategies. As an alternative to volatilizing mercury, we are using several new genes to construct plants that will hyperaccumulate mercury in above-ground tissues for later harvest. The Department of Energy's Oak Ridge National Laboratory and Brookhaven National Laboratory have sites with significant levels of mercury contamination that could be cleaned by applying the scientific discoveries and new phytoremediation technologies described in this proposal. The knowledge and expertise gained by engineering plants to hyperaccumulate mercury can be applied to the remediation of other heavy metals pollutants (e.g., arsenic, cesium, cadmium, chromium, lead, strontium, technetium, uranium) found at several DOE facilities.

Meagher, Richard B.

1999-06-01

274

Relationship between mercury levels in hair and fish consumption in a population living near a hydroelectric tropical dam.  

PubMed

In the present study, total mercury (T-Hg) concentrations were assessed in human hair samples (n = 76) and fish muscle (n = 33) collected at Urrá dam, upstream Sinú river, northwestern Colombia. Based on interviews with study participants, weekly intakes of total mercury (WIT-Hg) and methylmercury (WIMeHg) by fish consumption were also estimated. T-Hg concentrations in hair samples ranged from 0.40 to 24.56 ?g/g dw. The highest concentrations were recorded in children (CH) (2-15 years old, n = 24) with significant differences (p < 0.05) with respect to women of childbearing age (WCHA) (16-49 years old, n = 29) and the rest of the population (RP) (n = 23), which were not significantly different. The highest T-Hg concentrations in muscle tissue were recorded in the carnivorous fish (0.65-2.25 ?g/g wet weight, ww), with significant differences (p < 0.05) compared to non-carnivorous fish (0.16-0.54 ?g/g ww). WIT-Hg recorded the highest values in CH (2.18-50.41 ?g/kg/week), with significant differences (p < 0.05) with respect to WCHA (2.02-23.54 ?g/kg/week) and RP (1.09-24.71 ?g/kg/week), which were not significantly different. Correlation analysis showed a significant relationship between weekly fish consumption and hair T-Hg in CH (r = 0.37, p < 0.05) and WCHA (r = 0.44, p < 0.05). This association was also observed with the number of days per week with fish consumption in CH (r = 0.37, p < 0.05) and WCHA (r = 0.45, p < 0.05). These results suggest that Hg exposure in people inhabiting the Urrá dam should be carefully monitored, particularly in vulnerable groups such as CH and WCHA. PMID:23242864

Marrugo-Negrete, José Luis; Ruiz-Guzmán, Javier Alonso; Díez, Sergi

2013-02-01

275

Mercury concentrations in breast feathers of three upper trophic level marine predators from the western Aleutian Islands, Alaska  

USGS Publications Warehouse

Mercury (Hg) is a toxic element distributed globally through atmospheric transport. Agattu Island, located in the western Aleutian Islands, Alaska, has no history of point-sources of Hg contamination. We provide baseline levels of total mercury (THg) concentrations in breast feathers of three birds that breed on the island. Geometric mean THg concentrations in feathers of fork-tailed storm-petrels (Oceanodroma furcata; 6703 ± 1635, ng/g fresh weight [fw]) were higher than all other species, including snowy owl (Bubo scandiacus; 2105 ± 1631, ng/g fw), a raptor with a diet composed largely of storm-petrels at Agattu Island. There were no significant differences in mean THg concentrations of breast feathers among adult Kittlitz’s murrelet (Brachyramphus brevirostris; 1658 ± 1276, ng/g fw) and chicks (1475 ± 671, ng/g fw) and snowy owls. The observed THg concentrations in fork-tailed storm-petrel feathers emphasizes the need for further study of Hg pollution in the western Aleutian Islands.

Kaler, Robb S. A.; Kenney, Leah A.; Bond, Alexander L.; Eagles-Smith, Collin A.

2014-01-01

276

Regulation of tissue oxygen levels in the mammalian lens  

PubMed Central

Opacification of the lens nucleus is a major cause of blindness and is thought to result from oxidation of key cellular components. Thus, long-term preservation of lens clarity may depend on the maintenance of hypoxia in the lens nucleus. We mapped the distribution of dissolved oxygen within isolated bovine lenses and also measured the rate of oxygen consumption (Q?O2) by lenses, or parts thereof. To assess the contribution of mitochondrial metabolism to the lens oxygen budget, we tested the effect of mitochondrial inhibitors on Q?O2 and partial pressure of oxygen (PO2). The distribution of mitochondria was mapped in living lenses by 2-photon microscopy. We found that a steep gradient of PO2 was maintained within the tissue, leading to PO2 < 2 mmHg in the core. Mitochondrial respiration accounted for approximately 90% of the oxygen consumed by the lens; however, PO2 gradients extended beyond the boundaries of the mitochondria-containing cell layer, indicating the presence of non-mitochondrial oxygen consumers. Time constants for oxygen consumption in various regions of the lens and an effective oxygen diffusion coefficient were calculated from a diffusion–consumption model. Typical values were 3 × 10?5 cm2 s?1 for the effective diffusion coefficient and a 5 min time constant for oxygen consumption. Surprisingly, the calculated time constants did not differ between differentiating fibres (DF) that contained mitochondria and mature fibres (MF) that did not. Based on these parameters, DF cells were responsible for approximately 88% of lens oxygen consumption. A modest reduction in tissue temperature resulted in a marked decrease in Q?O2 and the subsequent flooding of the lens core with oxygen. This phenomenon may be of clinical relevance because cold, oxygen-rich solutions are often infused into the eye during intraocular surgery. Such procedures are associated with a strikingly high incidence of postsurgical nuclear cataract. PMID:15272034

McNulty, Richard; Wang, Huan; Mathias, Richard T; Ortwerth, Beryl J; Truscott, Roger J W; Bassnett, Steven

2004-01-01

277

Arsenic, cadmium, chromium, lead, mercury, and selenium levels in blood of four species of turtles from the Amazon in Brazil.  

PubMed

Using blood as a method of assessing metal levels in turtles may be useful for populations that are threatened or endangered or are decreasing. In this study the levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in blood of four species of turtles from the tributaries of the Rio Negro in the Amazon of Brazil were examined. The turtles included the six-tubercled Amazon (river) turtle (Podocnemis sextuberculata), red-headed Amazon (river) turtle (Podocnemis erythrocephala), big-headed Amazon (river) turtle (Peltocephalus dumerilianus), and matamata turtle (Chelus fimbriatus). Blood samples were taken from the vein in the left hind leg of each turtle. There were significant interspecific differences in the sizes of the turtles from the Rio Negro, and in concentrations of Pb, Hg, and Se; the smallest species (red-headed turtles) had the highest levels of Pb in their blood, while Se levels were highest in big-headed turtles and lowest in red-headed turtles. Hg in blood was highest in matamata, intermediate in big-headed, and lowest in the other two turtles. Even though females were significantly larger than males, there were no significant differences in metal levels as a function of gender, and the only relationship of metals to size was for Cd. Variations in metal levels among species suggest that blood may be a useful bioindicator. Metal levels were not high enough to pose a health risk to the turtles or to consumers, such as humans. PMID:19953418

Burger, Joanna; Jeitner, Christian; Schneider, Larissa; Vogt, Richard; Gochfeld, Michael

2010-01-01

278

Levels and temporal trends (1983-2003) of persistent organic pollutants (POPs) and mercury (Hg) in seabird eggs from Northern Norway.  

PubMed

The main objective of this study was to investigate possible temporal trends of persistent organic pollutants (POPs) and mercury in eggs of herring gulls (Larus argentatus), black-legged kittiwakes (Rissa tridactyla), common guillemots (Uria aalge) and Atlantic puffins (Fratercula arctica) in Northern Norway. Eggs were collected in 1983, 1993 and 2003. Egg concentrations of POPs (PCB congeners IUPAC numbers: CB-28, 74, 66, 101, 99, 110, 149, 118, 153, 105, 141, 138, 187, 128, 156, 157, 180, 170, 194, 206, HCB, alpha-HCH, beta-HCH, gamma-HCH, oxychlordane, trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor, p,p'-DDE, o,p'-DDD, p,p'-DDD, o,p'-DDT and p,p'-DDT) and mercury were quantified. Generally, POP levels decreased between 1983 and 2003 in all species. No significant temporal trend in mercury levels was found between 1983 and 2003. PMID:18262696

Helgason, Lisa B; Barrett, Rob; Lie, Elisabeth; Polder, Anuschka; Skaare, Janneche U; Gabrielsen, Geir W

2008-09-01

279

Environmental Geochemistry of Mercury Mines in Alaska  

NSDL National Science Digital Library

This U.S. Geological Survey fact sheet investigates potential environmental contamination around naturally occurring, mercury-rich mineral deposits in Alaska. Testing of mercury levels in streams and sediments is described, as well as mercury levels in fish downstream from mines and the environmental effects of mercury entering the food chain.

280

Lifespan mercury accumulation pattern in Liza aurata : Evidence from two southern European estuaries  

NASA Astrophysics Data System (ADS)

Mercury accumulation throughout the lifespan of Liza aurata (Risso, 1810) was analysed in four tissues (muscle, gills, liver and brain) in two southern European coastal ecosystems with distinct mercury contamination. Specimens from four to five age classes were captured in two sampling sites in the Ria de Aveiro (Laranjo bay and Mira), a system historically contaminated by industrial mercury, and in one site in the Mondego estuary, assumed as a mercury-free ecosystem. Mercury concentration in all tissues was found to be significantly higher in the Ria de Aveiro (Laranjo bay) compared to the Mondego, in accordance with the environmental contamination (water, sediments and suspended particulate matter). Significant differences inside the Ria de Aveiro (between the Mira and Laranjo bay) were only detected in the liver. This tissue registered the highest levels of mercury (ranging from 0.11 to 4.2 ?g g -1 ) in all sampling sites, followed by muscle, brain, and gills. In all sampling sites and tissues was denoted a mercury dilution pattern along the lifecycle (except in liver at the Mondego, the reference area where the concentrations are always very low). An exponential trend was found in the metal age variation patterns in Laranjo (the most contaminated area) and a linear trend in the Mira and the Mondego (the least contaminated areas). Organic mercury concentration in muscle generally accounted for over 95% of total mercury concentration, and followed the same accumulation pattern of total mercury. This fish species is of lesser importance in mercury transfer to adjacent coastal areas and although the consumption of fish from Laranjo may present some risk for the humans, this risk decreases with fish age/size.

Tavares, S.; Oliveira, H.; Coelho, J. P.; Pereira, M. E.; Duarte, A. C.; Pardal, M. A.

2011-10-01

281

Mercury hazards from gold mining to humans, plants, and animals  

USGS Publications Warehouse

Mercury contamination of the environment from historical and ongoing mining practices that rely on mercury amalgamation for gold extraction is widespread. Contamination was particularly severe in the immediate vicinity of gold extraction and refining operations; however, mercury--especially in the form of water-soluble methylmercury--may be transported to pristine areas by rainwater, water currents, deforestation, volatilization, and other vectors. Examples of gold mining-associated mercury pollution are shown for Canada, the United States, Africa, China, the Philippines, Siberia, and South America. In parts of Brazil, for example, mercury concentrations in all abiotic materials, plants, and animals--including endangered species of mammals and reptiles--collected near ongoing mercury-amalgamation gold mining sites were far in excess of allowable mercury levels promulgated by regulatory agencies for the protection of human health and natural resources. Although health authorities in Brazil are unable to detect conclusive evidence of human mercury intoxication, the potential exists in the absence of mitigation for epidemic mercury poisoning of the mining population and environs. In the United States, environmental mercury contamination is mostly from historical gold mining practices, and portions of Nevada remain sufficiently mercury-contaminated to pose a hazard to reproduction of carnivorous fishes and fish-eating birds. Concentrations of total mercury lethal to sensitive representative natural resources range from 0.1 to 2.0 ug/L of medium for aquatic organisms; from 2200 to 31,000 ug/kg body weight (acute oral) and 4000 to 40,000 ug/kg (dietary) for birds; and from 100 to 500 ug/kg body weight (daily dose) and 1000 to 5000 ug/kg diet for mammals. Significant adverse sublethal effects were observed among selected aquatic species at water concentrations of 0.03 to 0.1 ug Hg/L. For some birds, adverse effects--mainly on reproduction--have been associated with total mercury concentrations (in ug/kg fresh weight) of 5000 in feather, 900 in egg, and 50 to 100 in diet; and with daily intakes of 640 ug/kg body weight. Sensitive nonhuman mammals showed significant adverse effects of mercury when daily intakes were 250 ug/kg body weight, when dietary levels were 1100 ug/kg, or when tissue concentrations exceeded 1100 ug/kg. Proposed mercury criteria for protection of aquatic life range from 0.012 ug/L for freshwater life to 0.025 ug/L for marine life; for birds, less than 100 ug/kg diet fresh weight; and for small mammals, less than 1100 ug/kg fresh weight diet. All of these proposed criteria provide, at best, minimal protection.

Eisler, R.

2004-01-01

282

Mercury levels in muscle of six species of turtles eaten by people along the Rio Negro of the Amazon basin.  

PubMed

Mercury levels in the Amazon River are generally high, but there are no published studies on Hg levels in turtles from the region. In this study, levels of Hg were examined in the muscle of six species of turtles in the Rio Negro in the Amazon basin of Brazil, including Podocnemis unifilis, Podocnemis expansa, Podocnemis erythrocephala, Podocnemis sextuberculata, Peltocephalus dumerilianus, and Chelus fimbriatus. It is important to analyze Hg levels in chelonians in this region because of the potential health risk to humans and other receptors that eat them, as well as their potential use as bioindicators. The effect of sex, weight, and carapace length on Hg concentrations in turtle muscle was examined to determine if the levels represent a health risk to riverine people. There was a significant interspecific difference in Hg levels but no differences as a function of size or gender. The highest Hg level was found in Chelus fimbriatus (mean = 432 ppb, standard deviation +/- 196 ppb), followed by Peltocephalus dumerilianus (106 +/- 41 ppb), Podocnemis expansa (62 +/- 49 ppb), P. sextuberculata (61 +/- 40 ppb), P. unilifis (35 +/- 17 ppb), and P. erythrocephala (33.1 +/- 17 ppb). Of the species studied, the piscivorous C. fimbriatus had the highest Hg level. Hg levels in turtles were similar to the levels found in fish from the same basin. Levels of Hg in the muscle of C. fimbriatus are sufficiently high to pose a potential risk to humans who consume them. This study represents the first comparative study of Hg levels in muscle of six species of turtles. PMID:19621205

Schneider, Larissa; Belger, Lauren; Burger, Joanna; Vogt, Richard C; Ferrara, Camila R

2010-02-01

283

JV Task 96 - Phase 2 - Investigating the Importance of the Mercury-Selenium Interaction  

SciTech Connect

In order to improve the understanding of the mercury issue, it is vital to study mercury's effects on selenium physiology. While mercury present in the environment or food sources may pose health risks, the protective effects of selenium have not been adequately considered in establishing regulatory policy. Numerous studies report that vulnerability to mercury toxicity is inversely proportional to selenium status or level. However, selenium status has not been considered in the development of the reference dosage levels for mercury exposure. Experimental animals fed low-selenium diets are far more vulnerable to mercury toxicity than animals fed normal selenium, and animals fed selenium-rich diets are even more resistant. Selenium-dependent enzymes in brain and endocrine tissues can be impaired by excessive mercury exposure, apparently because mercury has an extremely high binding affinity for selenium. When selenium becomes bound to mercury, it is unable to participate in the metabolic cycling of selenoprotein synthesis. Because of mercury-dependent impairments of selenoprotein synthesis, various antioxidant and regulatory functions in brain biochemistry are compromised. This report details a 2-year multiclient-funded research program designed to examine the interactions between mercury and selenium in animal models. The studies explored the effects of dietary intakes of toxic amounts of methylmercury and the protective effects of the normal dietary range of selenium in counteracting mercury toxicity. This study finds that the amounts of selenium present in ocean fish are sufficient to protect against far larger quantities of methylmercury than those present in typical seafoods. Toxic effects of methylmercury exposure were not directly proportional to mercury concentrations in blood, brain, or any other tissues. Instead, mercury toxicity was proportional to molar ratios of mercury relative to selenium. In order to accurately assess risk associated with methylmercury or mercury exposures, mercury-selenium ratios appear to be far more accurate and effective in identifying risk and protecting human and environmental health. This study also finds that methylmercury toxicity can be effectively treated by dietary selenium, preventing the death and progressive disabilities that otherwise occur in methylmercury-treated subjects. Remarkably, the positive response to selenium therapy was essentially equivalent regardless of whether or not toxic amounts of methylmercury were still administered. The findings of the Physiologically Oriented Integration of Nutrients and Toxins (POINT) models of the effects of mercury and selenium developed in this project are consistent with the hypothesis that mercury toxicity arises because of mercury-dependent inhibition of selenium availability in brain and endocrine tissues. This appears to occur through synergistic effects of mercury-dependent inhibition of selenium transport to these tissues and selective sequestration of the selenium present in the tissues. Compromised transport of selenium to the brain and endocrine tissues would be particularly hazardous to the developing fetus because the rapidly growing tissues of the child have no selenium reserves. Therefore, maternal consumption of foods with high mercury-selenium ratios is hazardous. In summation, methylmercury exposure is unlikely to cause harm in populations that eat selenium-rich diets but may cause harm among populations that consume certain foods that have methylmercury present in excess of selenium.

Nicholas Ralston; Laura Raymond

2008-03-01

284

LONG-TERM CHANGES IN MERCURY CONCENTRATIONS IN FISH FROM THE MIDDLE SAVANNAH RIVER  

SciTech Connect

Total mercury levels were measured in largemouth bass (Micropterus salmoides), ''sunfishes'' (Lepomis spp)., and ''catfish'' (primarily Ameiurus spp.) from 1971 to 2004 in the middle reaches of the Savannah River, which drains the coastal plain of the southeastern U.S. Mercury levels were highest in 1971 but declined over the next ten years due to the mitigation of point sources of industrial pollution. Mercury levels began to increase in the 1980s as a possible consequence of mercury inputs from tributaries and associated wetlands where mercury concentrations were significantly elevated in water and fish. Mercury levels in Savannah River fish decreased sharply in 2001-2003 coincident with a severe drought in the Savannah River basin, but returned to previous levels in 2004 with the resumption of normal precipitation. Regression models showed that mercury levels in Savannah River fish changed significantly over time and were affected by river discharge. Despite temporal changes, there was little overall difference in Savannah River fish tissue mercury levels between 1971 and 2004.

Paller, M; Bill Littrell, B

2007-01-02

285

Laboratory Protocol for Measuring the Bioaccumulation of Mercury by Earthworms  

NASA Astrophysics Data System (ADS)

Protocol was developed for a series of laboratory tests to determine if Canadian earthworms ( Lumbricus terrestris) can hyperaccumulate mercury from the soil in which they live. Two batches of 300 hundred worms each were measured for mercury uptake by establishing 3 populations (one control and two of known contamination). Populations were sampled every two weeks. Worm lengths were measured as an indicator of worm age and health. Worm tissue was processed by a modified EPA Method 7470 consisting of freeze drying, vacuum extraction, oxidation and acid extraction of the mercury. Each sample needed 2.000 g dry weight of worm tissue required 5 to 6 worms to be homogenized. Mercury concentration in the extraction fluid was measured by a CETAC M-6100 cold vapor mercury analyzer with an ASX-400 Autosampler having a method detection limit of 0.05 ppb. QA/QC activities such as calibration of instrumentation, spike samples, blank samples, reagent control samples, triplicate samples, and standard samples ensure acurate and precise measurements of mercury levels in tissue samples.

Steffy, D.; Nichols, A.; McLaughlin, A.

2007-12-01

286

Increased striatal dopamine synthesis is associated with decreased tissue levels of tyrosine.  

PubMed

Tyrosine levels do not generally affect indices of dopamine (DA) synthesis or efflux under basal conditions, but can do so when DA synthesis is increased. One possibility is that a high rate of DA synthesis depletes the normally adequate pool of endogenous tyrosine. To study this, we administered drugs known to preferentially increase striatal DA synthesis and examined DOPA levels in striatal microdialysate during perfusion with NSD-1015. In additional groups, we also measured DA, tyrosine and large neutral amino acids in striatal microdialysate, as well as in tissue from striatum and medial prefrontal cortex (MPFC). gamma-butyrolactone (GBL) (750 mg/kg i.p.) increased DOPA levels in striatal microdialysate, increased tissue DA levels in the MPFC and striatum, but lowered tissue tyrosine levels only in striatum. In striatal microdialysate, GBL markedly lowered DA levels; tyrosine levels were only marginally lower. Haloperidol (HAL) (1.0 mg/kg s.c.)+/-amfonelic acid (AFA) (5 mg/kg i.p.) increased striatal DOPA accumulation, increased striatal DA efflux, lowered striatal tissue tyrosine levels, but did not affect microdialysate tyrosine levels. There were no consistent changes in levels of other large neutral amino acids. We conclude that increased tyrosine hydroxylation can significantly deplete the endogenous pool of tyrosine. Under such conditions, near normal extracellular tyrosine levels are maintained despite lower tissue levels. The data are consistent with a net transfer of tyrosine from non-DAergic cells to DA terminals in support of DA synthesis. PMID:16934236

Bongiovanni, Rodolfo; Young, Damon; Newbould, Erica; Jaskiw, George E

2006-10-18

287

Changes in brain monoamine levels and monoamine oxidase activity in the catfish, Clarias batrachus, during chronic treatments with mercurials  

SciTech Connect

In mammals, the central nervous system is the primary target for CH{sub 3}Hg poisoning which is clinically known as Minamata disease. Hg is a widely recognized neurotoxin and has been reported to impair brain monoamine neurotransmitter metabolism. Reports on effects of Hg on brain monoamine activity in fishes are scarce. In the present study, therefore, changes in the brain monoamine levels and the degradation enzyme, monoamine oxidase (MAO), are described in the catfish, Clarias batrachus, exposed to sublethal concentrations of mercuric chloride (HgCl{sub 2}-inorganic Hg), methylmercuric chloride (CH{sub 3}HgCl-organic Hg), and a commercial mercurial fungicide formulation, emisan 6 (methoxyethyl Hg-organic Hg) for 45, 90 and 180 d during gonadal recrudescence. These intervals correspond to late preparatory, prespawning and spawning phases, respectively, of the annual reproductive cycle of the catfish.

Kirubagaran, R.; Joy, K.P. (Banaras Hindu Univ., Varanasi (India))

1990-07-01

288

Corticosterone in relation to tissue cadmium, mercury and selenium concentrations and social status of male lesser scaup (Aythya affinis).  

PubMed

Combined lesser scaup (Aythya affinis) and greater scaup (A. marila) populations have declined steadily from the 1970s. Accompanying the population decline have been two shifts in lesser scaup demographics: a decrease in the proportion of young birds and an increase in male to female ratio. In addition, there are concerns about potential effects of contaminants and trace elements. These metals may influence the stress response and corticosterone secretion. We examined impacts of cadmium, selenium and mercury on the stress response in relation to social status in male lesser scaup near Yellowknife, NWT May to June 2004 and 2005. Kidney cadmium and liver selenium and mercury ranged 0.78-93.6, 2.12-9.64, and 0.56-3.71 microg/g, dry weight, respectively. Results suggest that corticosterone release may be influenced by complex contaminant interactions in relation to body condition and body size. When cadmium was high and birds were in good body condition, there was a negative relationship between liver selenium and corticosterone (R(2) = 0.60, n = 10, P = 0.008) but not in birds with poor body condition (R(2) = 0.07, n = 9, P = 0.50). Unfortunately we were unable to draw any conclusions about metals and social status in relation to corticosterone or glucose and T(4). This study emphasizes the complex nature of biological systems and the importance of considering interactions to characterize effects of metals. PMID:18677562

Pollock, Brady; Machin, Karen L

2009-01-01

289

Determination of mercury in fish from rivers and lakes in Hungary by atomic absorption technique.  

PubMed

In 1975, in cooperation with 8 County Hygienic Stations, total mercury content in fish from rivers and lakes in Hungary was measured. The mercury content in fish muscle-tissue from 164 fish samples averaged 0.36 mg/kg. Average levels in different fish species ranged from 0.10 to 0.57 mg/kg. The amount of mercury in fish from rivers and lakes, with the exception of the Danube, was, in general, lower than the tolerance level (0.50 mg/kg) as adopted in many countries. Mercury levels in fish from Lake Balaton did not amount to more than 0.30 mg/kg. The circulating cold vapour atomic absorption method was used to determined the mercury content in the fish samples. PMID:888150

Gergely, A; Soós, K; Erdélyi, L; Cieleszky, V

1977-06-01

290

MERCURY IN MARINE LIFE DATABASE  

EPA Science Inventory

The purpose of the Mercury in Marine Life Project is to organize information on estuarine and marine species so that EPA can better understand both the extent of monitoring for mercury and level of mercury contamination in the biota of coastal environments. This report follows a ...

291

ATMOSPHERIC MERCURY TRANSPORT AND DEPOSITION  

EPA Science Inventory

The current state of our scientific understanding the mercury cycle tells us that most of the mercury getting into fish comes from atmospheric deposition, but methylation of that mercury in aquatic systems is required for the concentrations in fish to reach harmful levels. We st...

292

2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN LEVELS IN ADIPOSE TISSUE OF VIETNAM VETERANS  

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been detected at levels ranging from 20 to 173 parts per trillion in adipose tissue from three Vietnam veterans who were 'heavily exposed' to Herbicide Orange. Some tissue samples from other Vietnam veterans and from controls also co...

293

Preliminary evaluation of the use of homing pigeons as biomonitors of mercury in urban areas of the USA and China.  

PubMed

Mercury was determined in the tissues (feather, lung, liver, and kidney) of homing pigeons (Columbia livia domestica) from both the USA (Glendora, California and Midland, Texas) and China (Beijing and Chengdu). Among these cities, mercury concentrations were greatest in samples from Beijing, which is known to have relatively high levels of airborne mercury. Among the tissues, levels were highest in the feather, followed by kidney, liver, and lung. There was no significant trend for mercury with pigeon age, weight, or sex, except for mercury with bird weight in the lung of the Beijing samples. Overall, the data adds to the growing body of evidence that the homing pigeon can serve as a useful biomonitor in urban areas. PMID:23229303

Cizdziel, James V; Dempsey, Sara; Halbrook, Richard S

2013-03-01

294

Temporal trends (1989-2011) in levels of mercury and other heavy metals in feathers of fledgling great egrets nesting in Barnegat Bay, NJ.  

PubMed

There is an abundance of data for levels of metals from a range of species, but relatively few long-term time series from the same location. In this paper I examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers from fledgling great egrets (Ardea alba) collected at nesting colonies in Barnegat Bay, New Jersey from 1989 to 2011. The primary objectives were to test the null hypotheses that (1) There were no temporal differences in metal levels in feathers of fledgling great egrets, and (2) Great egrets nesting in different areas of Barnegat Bay (New Jersey) did not differ in metal levels. There were significant yearly variations in levels of all heavy metals in feathers of fledgling great egret, but levels decreased significantly from 1989 to 2011 only for lead (1,470 ppb to 54.3 ppb), cadmium (277 ppb to 30.5 ppb), and manganese (only since 1996; 2,669 ppb to 329 ppb)). Although mercury levels decreased from 2003-2008 (6,430 ppb to 1,042 ppb), there was no pattern before 2003, and levels increased after 2008 to 2,610 ppb in 2011. Lead, cadmium, chromium, manganese and mercury were higher in feathers from great egrets nesting in the northern part of the bay, and selenium was highest in feathers from mid-bay. The lack of a temporal decline in mercury levels in feathers of great egrets is cause for concern, since the high levels in feathers from some years (means as high as 6,430 ppb) are in the range associated with adverse effects (5,000 ppb for feathers). PMID:23434313

Burger, Joanna

2013-04-01

295

Mercury Quest  

NSDL National Science Digital Library

In this module, students pretend they have been hired as an environmental consulting firm to deliver testimony for the hearing to develop a mercury pollution reduction plan for the State. In order to accomplish this task their consulting company must: inventory and assess current sources of mercury pollution to the extent feasible, including both (fictitious) Ramford County and regional sources of mercury pollution; review the current science on mercury deposition, transport, and exposure pathways; review the current science on the impacts of mercury pollution on public health and ecosystems; review existing mercury pollution policies in other states and in the US; and review strategies for clean up and reduction of exposure to mercury.

296

Levels of persistent organic pollutant residues in human adipose and muscle tissues in Singapore.  

PubMed

Persistent organic pollutants (POPs), due to their persistence and bioconcentration in lipid-rich tissue, bioaccumulate in food chains, resulting in elevated concentrations in humans. This study was performed to determine and compare levels of POPs in human adipose and muscle tissues in the female population of Singapore. In total, 36 human adipose tissues and 8 human muscle tissues were collected from volunteer expectant mothers admitted to the National University Hospital Singapore for cesarean section delivery between August 2003 and January 2005. Samples were analyzed using a validated and quality-assured gas chromatography-mass spectroscopy (GC-MS) method in conjunction with microwave-assisted extraction (MAE). Analytes recoveries from certified reference materials, that is, IRMM-446 (polychlorinated biphenyls [PCBs] in pork fat) and BCR-430 (organochlorine pesticides in pork fat), were between 70 and 130%, indicating reliable analytical precision for this methodology. MAE efficiency for polybrominated diphenyl ethers (PBDEs) was compared to Soxhlet extraction (SE) efficiency and yielded comparable results (variation < 13%). Analytical results indicate that p,p'-DDE of the dichlorodiphenyltrichloroethane (DDT) residues group is the predominant compound in adipose tissue, followed by beta-hexachlorocyclohexane (beta-HCH) among HCH isomers, then hexachlorobenzene (HCB) compound and specific PCB and PBDE congeners. Among the 36 adipose tissues, the lipid contents in adipose tissue were in the range of 60% to 95%, while in the 8 muscle tissues, lipids were undetectable. However, the profile of PCBs and pesticide residues present in muscle tissues were similar to those in adipose tissues. PMID:16982531

Li, Qing Qing; Loganath, Annamalai; Chong, Yap Seng; Tan, Jing; Obbard, Jeffrey Philip

2006-11-01

297

The effect of mercury and PCBs on organisms from lower trophic levels of a Georgia salt marsh.  

PubMed

We examined several indicators of salt marsh function, focusing on primary producers, microbes, and grass shrimp, at a Superfund site (LCP) contaminated with mercury and polychlorinated biphenyls (PCBs) and a reference site (Cross-River) in Georgia. Primary production of Spartina alterniflora was assessed by measuring peroxidase activity (POD), glutathione concentration (tGSH), photosynthesis (A(net)), and transpiration (E). Microbial populations were assessed by measuring living-fungal standing crop (as ergosterol) and Microtox(R). Grass shrimp (Palaemonetes pugio) reproductive potential was determined by measuring individual egg mass, average egg area, brood size, and brood mass of gravid females. Comparison of the sites suggested that P. pugio reproduction was affected at the LCP site, but we were unable to document clear negative effects on other organisms we investigated. Due to natural environmental gradients, the Cross-River site may not have been a perfect control for the LCP site. Therefore, data from just the LCP site were reanalyzed using multiple regression. Fungal biomass was related to methylmercury concentrations, but the direction of the relationship differed between wholly dead shoots (positive) and partially dead shoots (negative). S. alterniflora POD was positively related to methylmercury concentrations. S. alterniflora A(net) and E were negatively related to elevation and salinity, respectively. Despite high levels of contamination at the LCP site, our results provided only suggestive evidence for impacts on organisms at lower trophic levels. PMID:11116336

Wall, V D; Alberts, J J; Moore, D J; Newell, S Y; Pattanayek, M; Pennings, S C

2001-01-01

298

Low Systemic Testosterone Levels Induce Androgen Maintenance in Benign Rat Prostate Tissue  

PubMed Central

Prostate cancer (PC) is both an age and androgen-dependent disease. Paradoxically, systemic levels of androgens decline with age as the risk of PC rises. While there is no correlation between systemic androgen levels and the risk of PC, systemic androgen levels do not reflect the levels of androgen in prostate tissue. In metastatic PC, changes in the androgen biosynthesis pathway during hormone therapy cause increased levels of androgens in cancer tissue and contribute to continued androgen receptor (AR) signaling. It is possible that similar changes occur in normal prostate tissue as androgens decline with age and that this contributes to tumorigenesis. We sought to determine if the rat prostate is able to maintain functional levels of androgens despite low serum testosterone (T). Rats were castrated and implanted with capsules to achieve castrate, normal, sub- and supra-physiological levels of T. After six weeks of treatment, LC-MS/MS was used to quantify the levels of T and dihydrotestosterone (DHT) in serum and prostate tissue. QRT-PCR was used to quantify expression of genes involved in the androgen/AR signaling axis. Despite having significantly different levels of T and DHT in the serum, T and DHT concentrations in prostate tissue from different T treatment groups were very similar. Furthermore, the expression of androgen-regulated genes in the prostate was similar among all T treatment groups, demonstrating that the rat prostate can maintain a functional level of androgens despite low serum T levels. Low T treatment resulted in significant alterations in the expression of androgen biosynthesis genes, which may be related to maintaining functional androgen levels. PMID:23709748

Zhou, Ye; Otto-Duessel, Maya; He, Miaoling; Markel, Susan; Synold, Tim; Jones, Jeremy O.

2013-01-01

299

Mercury contamination in bank swallows and double-crested cormorants from the Carson River, Nevada  

SciTech Connect

An ecological risk assessment was performed in conjunction with a remedial investigation at the Carson River Mercury Site (CRMS) in northwestern Nevada. Large quantities of mercury used in the processing of gold and silver during mining operations in the mid to late 1800s are distributed throughout the Carson River ecosystem. Previous investigations indicated elevated levels of mercury in soil, sediment, water, and the aquatic food chain. Bird exposure to mercury was determined by measuring total mercury and monomethyl mercury in blood and feather samples from 15 unfledged double-crested cormorants (Phalacrocorax auritus), and in blood, feather, and liver samples from 18 juvenile bank swallows (Riparia riparia) at both the CRMS and uncontaminated background locations. Monomethyl mercury accounted for 90 to 98% of the total mercury in the samples. Total mercury concentrations in bird tissues collected at the CRMS were significantly higher than at background locations. Average total mercury concentrations (wet weight) for the swallow blood, liver, and feather samples collected at the CRMS were 2.63, 3.96, and 2.01 mg/kg, respectively; compared with 0.74, 1,03, and 1.84 mg/kg, respectively at the background area. Average total mercury concentrations for cormorant samples collected at the CRMS were 17.07 mg/kg for blood, and 105.1 1 mg/kg for feathers. Cormorant samples collected at the background location had average total mercury concentrations of 0.49 mg/kg for blood and 8.99 mg/kg for feathers. Results are compared with published residue-effects levels to evaluate avian risks.

Kim, R.; Brewer, R.; Peterson, S.C.; Mach, C. [Ecology and Environment, Inc., Buffalo, NY (United States)

1995-12-31

300

A comparative study of diazepam levels in bone marrow versus serum, saliva and brain tissue  

Microsoft Academic Search

Summary The distribution of diazepam in biological fluids and tissues of rats was examined 1, 2, 4 and 8 h after intraperitoneal administration by using a radioimmunoassay with specific anti-diazepam antibody. The diazepam levels in serum, saliva, brain and bone marrow decreased over a period of 2h and levelled off 4h after administration. The diazepam concentration in bone marrow was

T. Takatori; S. Tomii; K. Terazawa; M. Nagao; M. Kanamori; Y. Tomaru

1991-01-01

301

Auto-aggressive metallic mercury injection around the knee joint: a case report  

PubMed Central

Background Accidental or intentional subcutaneous and/or intramuscular injection of metallic mercury is an uncommon form of poisoning. Although it does not carry the same risk as mercury vapour inhalation, it may cause destructive early and late reactions. Case Presentation Herein we present the case of a 29-year-old male patient who developed an obsessive-compulsive disorder causing auto-aggressive behaviour with injection of elemental mercury and several other foreign bodies into the soft tissues around the left knee about 15 years before initial presentation. For clinical examination X-rays and a CT-scan of the affected area were performed. Furthermore, blood was taken to determine the mercury concentration in the blood, which showed a concentration 17-fold higher than recommended. As a consequence, the mercury depots and several foreign bodies were resected marginally. Conclusion Blood levels of mercury will decrease rapidly following surgery, especially in combination with chelating therapy. In case of subcutaneous and intramuscular injection of metallic mercury we recommend marginal or wide excision of all contaminated tissue to prevent migration of mercury and chronic inflammation. Nevertheless, prolonged clinical and biochemical monitoring should be performed for several years to screen for chronic intoxication. PMID:22093686

2011-01-01

302

Phytotoxicity of biosolids and screening of selected plant species with potential for mercury phytoextraction.  

PubMed

Mercury contaminated stockpiles of biosolids (3.5-8.4 mg kg(-1) Hg) from Melbourne Water's Western Treatment Plant (MW-WTP) were investigated to evaluate the possibility for their phytoremediation. Nine plant species (Atriplex codonocarpa, Atriplex semibaccata, Austrodanthonia caespitosa, Brassica juncea, Brassica napus, Gypsophila paniculata, Sorghum bicolor, Themeda triandra and Trifolium subterraneum) were screened for phytoextraction potential in Hg-contaminated biosolids from MW-WTP. In addition, the same plant species were germinated and grown in two other substrates (i.e. potting mix and potting mix spiked with mercury(II)). Growth measurements and the mercury uptake for all three substrates were compared. Some plant species grown in potting mix spiked with mercury(II) grew more vigorously than in the other two substrates and showed higher levels of sulphur in their tissues. These results suggested that the mercury stress activated defence mechanisms and it was hypothesised that this was the likely reason for the enhanced production of sulphur compounds in the plant species studied which stimulated their growth. Some species did not grow in biosolids because of the combined effect of high mercury toxicity and high salt content. Atriplex conodocarpa and Australodanthonia caespitose proved to be the most suitable candidates for mercury phytoextraction because of their ability to translocate mercury from roots to the above-ground tissues. PMID:19775810

Lomonte, Cristina; Doronila, Augustine I; Gregory, David; Baker, Alan J M; Kolev, Spas D

2010-01-15

303

Influence of ecological factors and of land use on mercury levels in fish in the Tapajós River basin, Amazon.  

PubMed

Mercury (Hg) contamination of riparian communities and of environmental compartments of the Amazon can be directly related to the occupation of the territory. The objective of this study was to identify the characteristics of aquatic environments that are associated with high levels of Hg in ichthyofauna. Our research aimed at determining the influence of variables related to fish ecology, types of aquatic environment, fishing activities by local riparian populations, and watershed use on the levels of contamination of ichthyofauna. Six sites were sampled during two distinct periods of the hydrological cycle: at the beginning of descending waters and during low waters. We focused on ten dominant fish species representing four trophic levels: Curimata inornata, Geophagus proximus, Schizodon vittatum, Leporinus fasciatus, Anostomoides laticeps, Hemiodus unimaculatus, Caenotropus labyrinthicus, Hoplias malabaricus, Plagioscion squamosissimus, Acestrorhynchus falcirostris. The study sites, which included lotic and lentic habitats, are exploited year-round by local riparian communities. Spatial variations in Hg contamination in ichthyofauna were determined by factorial analysis of variance taking into account fish diets, seasons, and sampling sites. Multiple regressions were used to check the influence of ecological and anthropogenic variables and variables related to watershed uses, on Hg levels in key species representing the four trophic groups. Each variable was checked independently. Next, multiple regressions were used to verify the concomitant influence of selected variables. Independently of the study site and the phase of the hydrologic cycle, fish Hg contamination followed the trend piscivores>omnivores>herbivores>detritivores. In all the aquatic study sites, Hg levels measured in predatory species were often higher than the 500 ng/g fresh weight threshold. Mean Hg levels in key species were significantly higher during descending waters in lotic environments, and during low waters in lentic environments. Data from this study demonstrated that simple models based on watershed use and on easily obtained variables such as the suspended particulate matter (SPM) load and SPM Hg concentrations, number of inhabitants, habitat types, and the stage in the hydrological cycle enable very good prediction of Hg levels in fish. Our cartographical data clearly showed that the watershed site with the highest aquatic vegetation cover (6% of the open water body) and with the lowest forest cover (62% of the land) corresponded to the highest Hg concentrations in fish. Conversely, the watershed site with 94% forest cover and 1% aquatic vegetation corresponded to the lowest levels Hg concentrations in fish. These results suggest that land uses of watersheds play a key role in the level of Hg contamination of local ichthyofauna. PMID:19356749

Sampaio da Silva, D; Lucotte, M; Paquet, S; Davidson, R

2009-05-01

304

Trace-level mercury ion (Hg2+) analysis in aqueous sample based on solid-phase extraction followed by microfluidic immunoassay.  

PubMed

Mercury is considered the most important heavy-metal pollutant, because of the likelihood of bioaccumulation and toxicity. Monitoring widespread ionic mercury (Hg(2+)) contamination requires high-throughput and cost-effective methods to screen large numbers of environmental samples. In this study, we developed a simple and sensitive analysis for Hg(2+) in environmental aqueous samples by combining a microfluidic immunoassay and solid-phase extraction (SPE). Using a microfluidic platform, an ultrasensitive Hg(2+) immunoassay, which yields results within only 10 min and with a lower detection limit (LOD) of 0.13 ?g/L, was developed. To allow application of the developed immunoassay to actual environmental aqueous samples, we developed an ion-exchange resin (IER)-based SPE for selective Hg(2+) extraction from an ion mixture. When using optimized SPE conditions, followed by the microfluidic immunoassay, the LOD of the assay was 0.83 ?g/L, which satisfied the guideline values for drinking water suggested by the United States Environmental Protection Agency (USEPA) (2 ?g/L; total mercury), and the World Health Organisation (WHO) (6 ?g/L; inorganic mercury). Actual water samples, including tap water, mineral water, and river water, which had been spiked with trace levels of Hg(2+), were well-analyzed by SPE, followed by microfluidic Hg(2+) immunoassay, and the results agreed with those obtained from reduction vaporizing-atomic adsorption spectroscopy. PMID:23186342

Date, Yasumoto; Aota, Arata; Terakado, Shingo; Sasaki, Kazuhiro; Matsumoto, Norio; Watanabe, Yoshitomo; Matsue, Tomokazu; Ohmura, Naoya

2013-01-01

305

Stevia, cyclamate and saccharin - natural and artificial sweeteners - exert no effect on sulfane levels in tissues.  

PubMed

The interactions among natural and artificial sweeteners and endogenous sulfur metabolism have never been investigated. CBA strain mice were administered orally stevia, cyclamate or saccharin in doses of 5 mg/kg of body weight in water solutions each. The measurements of the free and acid-labile sulfane (H2S) tissue concentrations in brain, heart, liver and kidney were performed with Siegel spectrophotometric modified method. No differences in comparisons between hydrogen sulfide concentrations in the control group and each sweetener group within every tissue type were noted. In conclusion, stevia, cyclamate and saccharine do not change the endogenous sulfur metabolism to the extent of causing sulfane tissue levels alterations. PMID:24858558

Wilinski, Bogdan; Opoka, Wlodzimierz; Somogyi, Eugeniusz; Piotrowska, Joanna; Wilinski, Jerzy

2013-01-01

306

Method and system for in vivo measurement of bone tissue using a two level energy source  

NASA Technical Reports Server (NTRS)

Methods and apparatus are provided for radiologically determining the bone mineral content of living human bone tissue independently of the concurrent presence of adipose and other soft tissues. A target section of the body of the subject is irradiated with a beam of penetrative radiations of preselected energy to determine the attenuation of such beam with respect to the intensity of each of two radiations of different predetermined energy levels. The resulting measurements are then employed to determine bone mineral content.

Cameron, J. R.; Judy, P. F. (inventors)

1976-01-01

307

Tocotrienol levels in adipose tissue of benign and malignant breast lumps in patients in Malaysia.  

PubMed

Data on dietary exposure to vitamin E by plasma or adipose tissue concentrations of alpha-tocopherol (alpha-T) in observational studies have failed to provide consistent support for the idea that alpha-T provides women with any protection from breast cancer. In contrast, studies indicate that alpha, gamma, and delta-tocotrienols but not alpha-T have potent anti-proliferative effects in human breast cancer cells. Our aim was to investigate whether there was a difference in tocopherol and tocotrienol concentrations in malignant and benign adipose tissue, in a Malaysian population consuming predominantly a palm oil diet. The study was undertaken using fatty acid levels in breast adipose tissue as a biomarker of qualitative dietary intake of fatty acids. The major fatty acids in breast adipose tissue of patients (benign and malignant) were oleic acid (45-46%), palmitic (28-29%) and linoleic (11-12%). No differences were evident in the fatty acid composition of the two groups. There was a significant difference (p=0.006) in the total tocotrienol levels between malignant (13.7 +/- 6.0 microg/g) and benign (20+/-6.0 microg/g) adipose tissue samples. However, no significant differences were seen in the total tocopherol levels (p=0.42) in the two groups. The study reveals that dietary intake influences adipose tissue fatty acid levels and that adipose tissue is a dynamic reservoir of fat soluble nutrients. The higher adipose tissue concentrations of tocotrienols in benign patients provide support for the idea that tocotrienols may provide protection against breast cancer. PMID:17704032

Nesaretnam, Kalanithi; Gomez, Patricia Alison; Selvaduray, Kanga Rani; Razak, Ghazali Abdul

2007-01-01

308

A comparison of mercury cycling in Lakes Michigan and Superior  

Microsoft Academic Search

Mercury cycling in Lake Superior and Lake Michigan was evaluated based on measurements of mercury levels, modeling of evasional fluxes, and development of first-order mass balance models. Total mercury, methylmercury, and dissolved gaseous mercury were measured on sampling cruises in Lake Michigan (2005) and Lake Superior (2006). Average total mercury concentrations in unfiltered surface water were higher in Lake Michigan

Jeffrey D. Jeremiason; Linda A. Kanne; Tara A. Lacoe; Melissa Hulting; Matt F. Simcik

2009-01-01

309

Mercury in turtles from the Asian food trade.  

E-print Network

??Mercury contamination threatens many ecosystems worldwide. Methyl mercury bioaccumulates at each trophic level, and biomagnifies within individuals over time. Long-lived turtles often occupy high trophic… (more)

Green, Aaliyah

2007-01-01

310

Reel danger: power plant mercury pollution and the fish we eat  

SciTech Connect

This study is based on the first available data from US EPA's ongoing National Study of Chemical Residues in Lake Fish Tissue. From 1999-2001, EPA collected approximately two composite samples of one predator fish species and one bottom-dwelling fish species at 260 lakes, for a total of 520 composite samples, or 2,547 fish. It was found that every fish tested was contaminated with mercury. 55% of the fish tested contained mercury levels that exceed EPA's 'safe' limit for women of childbearing age, and 76% exceeded the safe limit for children under age three. Predator fish, including smallmouth bass, walleye, largemouth bass, lake trout, and Northern pike, had the highest average mercury concentrations. Coal-fired power plants are the single largest source of mercury emissions, contributing 41% of US mercury emissions. They released 90,370 pounds of mercury into the air in 2002, the most recent year for which EPA data are available. In January 2004, the Bush administration issued a proposal for regulating mercury from power plants. In the author's opinion, the EPA's proposal would delay even modest reductions in mercury emissions from power plants until after 2025. In contrast, the Clean Air Act calls for the maximum achievable reductions by 2008. It is recommended that the Bush administration reverse course and require coal-fired power plants to reduce mercury emissions by at least 90% by 2008. 79 refs., 4 figs., 11 tabs., 3 apps.

Figdor, E. [US Public Interest Research Group Education Fund (US PIRG) for Clear the Air, Washington, DC (United States)

2004-08-15

311

Ammonium thiosulphate enhanced phytoextraction from mercury contaminated soil--results from a greenhouse study.  

PubMed

According to the 'hard and soft' acid-base principle, mercury is a 'soft metal' and will preferentially form soluble chemical complexes with sulphur-containing ligands. In this work mercury uptake by Chenopodium glaucum L. growing on mercury-contaminated soil was promoted using ammonium thiosulphate. The relative geochemical fractionation of mercury in the soil was subsequently investigated as a function of plant growth with and without thiosulphate amendment. The results indicate that the solubility of mercury is significantly increased through the application of thiosulphate to the soil. Substantially higher mercury levels were found in C. glaucum L. treated with 2 g kg(-1) thiosulphate of soil when compared to the non-treated plants. Compared with initial soil, soluble and exchangeable fractions were increased both in planted and planted treated plants. However, no significant difference was observed between the soils of the planted and planted treated plants. The oxide-bound mercury concentration was significantly decreased for the planted soil (treated and non-treated) at the end of the experiment. Moreover, this fraction was highly correlated with the plant tissue mercury concentration. Taken together, thiosulphate assisted phytoextraction could be used to reduce environmental risk apparent for mercury-contaminated soil through reducing the oxide bound fractions, while managing the bioavailable fractions (compared with no treated plant). PMID:21122988

Wang, Jianxu; Feng, Xinbin; Anderson, Christopher W N; Qiu, Guangle; Ping, Li; Bao, Zhengduo

2011-02-15

312

High levels of mercury contamination in multiple media of the Carson River Drainage Basin of Nevada: Implications for risk assessment  

Microsoft Academic Search

Approximately 5.5 x 10[sup 9] g (4.0 x 10[sup 5] l) of mercury was discharged into the Carson River Drainage Basin of west-central Nevada during processing of the gold- and silver-rich Comstock ore in the late 1800s. For the past 13 decades, mercury has been redistributed throughout 500 km[sup 2] of the basin, and concentrations are some of the highest

M. S. Gustin; G. E. Jr. Taylor; T. L. Leonard

1994-01-01

313

Silicon tissue assay: a measurement of capsular levels from chemotherapeutic port-a-catheter devices.  

PubMed

A plethora of data has been used to condemn and defend the role of silicone and its association with "adjuvant disease." In the ongoing attempt to enhance our knowledge, we have chosen to identify tissue silicon levels (n = 15) in capsules that form around chemotherapeutic port-a-catheter devices, which consist of a metal dome encapsuled by silicone. We have compared these levels with previously established silicon levels in augmented breast capsules, distant tissue sites in these same augmented women, and nonaugmented cadaveric tissues from various geographic locations in the United States. All specimens were harvested by a "no touch" technique, not formalin fixed, frozen, and shipped to an independent toxicology laboratory for analysis. Inductively coupled plasma atomic emission spectroscopy was employed to obtain the tissue silicon measurements. Results demonstrated silicon values ranging from nondetectable in 9 patients to as high as 41 micrograms/gm. These values fell in between our cadaveric (0.5 to 6.8 micrograms/gm) and augmented tissue silicon levels (18 to 8700 micrograms/gm). Although the sample size is small and the power of statistical analysis is low, there was no correlation between the patient's silicon level and age, type of cancer, type of chemotherapeutic agent, radiation therapy, or length of time the port-a-catheters were in place. Although detectable levels of silicon identified around port-a-catheter devices were higher than expected, it is impossible to make any conclusions about these levels and the role of a potential collagen-vascular disease. What we have shown, however, is that silicone breast implants may not be the only medical device that can elevate tissue silicon levels. Our data seem to suggest that there may be a progression of measurable tissue silicon levels based on the amount of environmental or device-related silicon exposure a person has had at a particular time in his or her life. It is our belief that as we identify these tissue silicon levels, they will serve as a baseline and reference for further scientific studies. PMID:9105363

Evans, G R; Baldwin, B J

1997-04-01

314

Serum Levels of Matrix Metalloproteinases-2 and -9 and Their Tissue Inhibitors in Inflammatory Neuromuscular Disorders  

Microsoft Academic Search

We monitored serum levels of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) before and during intravenously applied immunoglobulin (IVIG) therapy in 33 patients with chronic immune-mediated neuropathies and myopathies and 15 controls. Baseline MMP-2 and TIMP-2 serum levels were lower and MMP-9 and TIMP-1 serum levels higher in all patients compared to age-matched controls. Eight days after IVIG treatment,

S. Hurnaus; W. Mueller-Felber; D. Pongratz; B. G. H. Schoser

2006-01-01

315

Mercury levels in Great Lakes herring gull ( Larus argentatus) eggs, 1972–1992  

Microsoft Academic Search

Since 1971, the herring gull (Larus argentatus) has been used as a sentinel species for monitoring the levels of persistent contaminants in the Great Lakes ecosystem. In this study, 21 herring gull colonies in the Great Lakes and connecting channels were sampled during 1972–1976, 1981–1983, 1985 and 1992. For each year, 10 eggs (usually) were collected from each colony site

M. D. Koster; D. P. Ryckman; D. V. C. Weseloh; J. Struger

1996-01-01

316

Effects of brief hypoxia and hyperoxia on tissue element levels in the development chick embryo  

SciTech Connect

Brief hypoxia or hyperoxia has been shown to affect growth and metabolism of chick embryos during the later stages of development. The objective of this experiment was to alter the availability of oxygen to chick embryos developing in ovo and to determine the effects on tissue levels of Zn, Cu, Fe and Mn. Hypoxia reduced embryo, heart, brain and liver wts (wet wt), whereas, hyperoxia increased embryo, heart, lung and liver wts compared to normoxic controls. Chorioallantoic membrane (CAM) wt was increased by hypoxia and reduced by hyperoxia. Livers from hyperoxic embryos contained more Zn, Fe and Mn and less Cu than livers from hypoxic or normoxic embryos. Tissue levels of Zn, Cu, Fe and Mn were reduced in brains from hypoxic compared to hyperoxic or normoxic embryos. Hyperoxia increased the concentrations of Zn and Cu in CAM; whereas, hypoxia reduced the levels of Zn and Fe. The amounts of Zn and Cu were increased in hyperoxic compared to normoxic lungs. Hearts from hyperoxic embryos had more Zn, Cu and Mn than hypoxic or normoxic hearts. Hypoxic yolk sac contained more Zn, Cu and Mn than hyperoxic or normoxic yolk sac. Except for yolk sac, the amounts of Zn, Cu, Fe and Mn in tissues from normoxic embryos increased from day 15 to day 18 of incubation in concert with tissue growth. The authors conclude that the availability of O{sub 2} to the developing chick embryo affects tissue trace element levels either through its effects on tissue growth or via effects on the regulation of trace element uptake and assimilation by the tissues.

Richards, M.P.; Stock, M.K.; Metcalfe, J. (Dept. of Agriculture, Beltsville, MD (United States) Oregon Health Sciences Univ., Portland (United States))

1991-03-15

317

Mercury speciation in piscivorous fish from mining-impacted reservoirs  

USGS Publications Warehouse

Guadalupe Reservoir (GUA), California, and Lahontan Reservoir (LAH), Nevada, U.S. are both affected either directly or indirectly by the legacy of gold and silver mining in the Sierra Nevada during the nineteenth century. Analysis of total mercury in fish from these lentic systems consistently indicate elevated concentrations (>1 ??g??g-1 wet weight; hereinafter, all concentrations are reported as wet weight unless indicated otherwise) well above the U.S. Environmenal Protection Agency's human consumption advisory level for fish (<0.3 ??g??g-1). Replicate X-ray absorption near edge structure (XANES) analyses on largemouth bass and hybrid striped bass from GUA and LAH were performed to determine predominant chemical species of mercury accumulated by these high-trophic-level piscivores that are exposed to elevated mercury through trophic transfer in mining-impacted lentic systems. Despite distinct differences in mercury source, the proximity of the source, and concentrations of complexing ligands, results of XANES analysis clearly indicated that mercury accumulated in these individual fish from the two reservoirs were dominated by methylmercury cysteine complexes. These findings are consistent with results from commercial fish species inhabiting marine environments which are presumed to include differing mercury sources (e.g., atmospheric, hydrothermal, or benthic). The dominance of methylmercury cysteine complexes in muscle tissues of fish obtained from such contrasting environments and exposure conditions suggests that a generic toxicological model for the consumption of fish could be applicable over a wide range of ecologic settings. ?? 2007 American Chemical Society.

Kuwabara, J.S.; Arai, Y.; Topping, B.R.; Pickering, I.J.; George, G.N.

2007-01-01

318

Mercury burdens in Chinese mitten crabs (Eriocheir sinensis) in three tributaries of southern San Francisco Bay, California, USA  

USGS Publications Warehouse

Chinese mitten crabs (Eriocheir sinensis), endemic to Asia, were first reported in the San Francisco Bay in 1992. They are now established in nearly all San Francisco Bay tributaries. These crabs accumulate more metals, such as mercury, than crustaceans living in the water column. Because their predators include fish, birds, mammals and humans, their mercury burdens have an exceptional potential to impact the ecosystem and public health. We sought to elucidate the potential threat of mitten crab mercury burdens in three adjacent streams in southern San Francisco Bay, one of which is known to be contaminated with mercury. Mitten crabs had hepatopancreas concentrations of total mercury and methylmercury that did not differ among streams. The maximum burden we measured was below the action level of 1 ppm recommended by the USEPA. Hepatopancreas concentrations of methylmercury declined with increasing crab size, suggesting a mechanism for mercury excretion and that predators might reduce mercury exposure if they select larger crabs. Because mercury may be heterogeneously distributed among tissues, estimation of the impacts of crab mercury burdens on the environment requires more data on the feeding preferences of predators. Hepatopancreas concentrations of mercury decline with crab size, which may have important consequences for bio-magnification in food webs. ?? 2004 Elsevier Ltd. All rights reserved.

Hui, C.A.; Rudnick, D.; Williams, E.

2005-01-01

319

SFRSF: Mercury  

NSDL National Science Digital Library

This South Florida Restoration Science Forum page discusses the problem with mercury in restoring habitats and ecosystems in southern Florida. This study looks at the origin of mercury in the water and atmosphere, and how Everglades restoration will affect mercury risks. Managing water quality and quantity to reduce risks, and understanding the food web to determine entry points and biomagnification are also discussed. Locations where mercury toxicity is above the healthy limit are identified. There are links for more information provided.

320

The stem cell niche: tissue physiology at a single cell level  

PubMed Central

Stem cells are the critical unit affecting tissue maintenance, regeneration, and repair, with particular relevance to the tissues with high cell turnover. Stem cell regulation accommodates the conflicting needs of prompt responsiveness to injury and long-term preservation through quiescence. They are, in essence, the fundamental unit by which a tissue handles changing physiologic needs throughout the lifetime of the organism. As such, they are the focal point of dynamic tissue function, and their governance is physiology expressed at a cellular and molecular level. Here, we discuss the multiple components representing the stem cell niche in hematopoiesis and argue for a unbiased mapping of the niche constituents under different conditions as the first step in developing systems physiology. PMID:22945635

Hoggatt, Jonathan; Scadden, David T.

2012-01-01

321

N-Palmitoylethanolamine depot injection increased its tissue levels and those of other acylethanolamide lipids  

PubMed Central

N-Palmitoylethanolamine (NAE 16:0) is an endogenous lipid signaling molecule that has limited water solubility, and its action is short-lived due to its rapid metabolism. This poses a problem for use in vivo as oral administration requires a high concentration for significant levels to reach target tissues, and injection of the compound in a dimethyl sulfoxide- or ethanol-based vehicle is usually not desirable during long-term treatment. A depot injection of NAE 16:0 was successfully emulsified in sterile corn oil (10 mg/kg) and administered in young DBA/2 mice in order to elevate baseline levels of NAE 16:0 in target tissues. NAE 16:0 levels were increased in various tissues, particularly in the retina, 24 and 48 hours following injections. Increases ranged between 22% and 215% (above basal levels) in blood serum, heart, brain, and retina and induced an entourage effect by increasing levels of other 18 carbon N-Acylethanolamines (NAEs), which ranged between 31% and 117% above baseline. These results indicate that NAE 16:0 can be used as a depot preparation, avoiding the use of inadequate vehicles, and can provide the basis for designing tissue-specific dosing regimens for therapies involving NAEs and related compounds. PMID:23976843

Grillo, Stephanie L; Keereetaweep, Jantana; Grillo, Michael A; Chapman, Kent D; Koulen, Peter

2013-01-01

322

Mercury and Selenium in a Mining-Affected Watershed of the Rocky Mountain Northwest  

NASA Astrophysics Data System (ADS)

The moderating effect of selenium on mercury toxicity is well established, although mechanisms and environmental implications of this interaction are still a field of intensive research. The Upper Clark Fork River Basin in northwestern Montana offers a suitable field site to test some of the emerging models, as a history of intensive metals mining created sub-watersheds with variable combinations of mercury and selenium sources. To address various levels of the food web, we analyzed a preliminary set of sediments, fish tissues and osprey (Pandion haliaetus) blood samples from various locations throughout the watershed. Sediment mercury concentrations vary between 0.02 and over 10 mg/kg, and selenium in sediments ranges from undetectable to 5 mg/kg in the most contaminated reaches. Mercury levels in fish range from 0.03 to 1.5 mg/kg (wet wt) and are highly dependent on the geographic location, in addition to fish species and size. Mercury concentrations in blood of nestling osprey chicks vary between 97 and 730 ?g/L, with the majority of the variability explained by geographic location. Total mercury concentration in sediment can explain some of the variability in fish and ospreys; however, mercury accumulation in these organisms is also affected by factors such as the environmental methylation potential and possibly the sequestration of mercury in selenium compounds that are not prone to biomagnification in the food web. This hypothesis is supported by the geographic distribution of selenium and mercury levels in osprey blood: Relatively high selenium concentrations (~2000 ?g/L) are associated with the lowest blood mercury levels, despite relatively high mercury levels in the local sediments (~1 mg/kg). In reaches with the lowest selenium concentrations in osprey blood (430 ?g/L), the blood mercury levels are relatively high, despite very low sediment mercury levels. Analysis of this data points toward the role of bioavailable selenium in modifying the fate of mercury in the food web of a large river system in the Rocky Mountain Northwest.

Langner, H.

2011-12-01

323

Mercury residues in wood ducks and wood duck foods in eastern Tennessee  

SciTech Connect

Liver, breast muscle and body fat from 50 juvenile and five adult wood ducks (Aix sponsa) collected on the Holston River, Tennessee were analyzed for total mercury content. Black fly larvae (Simulium vittatum) sago pondweed (Potamogeton pectinatus), tapegrass (Vallisneria americanus), water stargrass (Heteranthera dubia), Elodea canadensis, and river bottom sediments were also analyzed to elucidate the distribution of mercury in the wood duck's environment. Liver tissues of juveniles contained the highest mean concentration of mercury (0.42 ppm). Mercury in breast muscle and body fat of juveniles averaged 0.15 and 0.10 ppm, respectively. Residues in corresponding tissues of adults were lower. Of environmental components tested, sediments had the highest mean concentration (0.76 ppm). Black fly larvae and aquatic plants had mean levels below 0.10 ppm.

Lindsay, R.C.; Dimmick, R.W.

1983-04-01

324

Mercury residues in wood ducks and wood duck foods in eastern Tennessee.  

PubMed

Liver, breast muscle and body fat from 50 juvenile and five adult wood ducks (Aix sponsa) collected on the Holston River, Tennessee were analyzed for total mercury content. Black fly larvae (Simulium vittatum) sago pondweed (Potamogeton pectinatus), tapegrass (Vallisneria americanus), water stargrass (Heteranthera dubia), Elodea canadensis, and river bottom sediments were also analyzed to elucidate the distribution of mercury in the wood duck's environment. Liver tissues of juveniles contained the highest mean concentration of mercury (0.42 ppm). Mercury in breast muscle and body fat of juveniles averaged 0.15 and 0.10 ppm, respectively. Residues in corresponding tissues of adults were lower. Of environmental components tested, sediments had the highest mean concentration (0.76 ppm). Black fly larvae and aquatic plants had mean levels below 0.10 ppm. PMID:6887432

Lindsay, R C; Dimmick, R W

1983-04-01

325

MERCURY SOURCE IDENTIFICATION AND RISK MANAGEMENT RECOMMENDATIONS FOR FISH TISSUE CONSUMPTION FROM LIVESTOCK PONDS ON THE CHEYENNE RIVER SIOUX TRIBAL LANDS.  

EPA Science Inventory

In a collaborative 3 year study with the Cheyenne River Sioux Tribe Department of Environmental Protection (CRST DEP), and the Agencies' Environmental Response Team (ERT, Edison N.J.) Region VIII investigated Hg levels in fish tissues from the Cheyenne River and Lake Oahe in nort...

326

Got Mercury?  

NASA Technical Reports Server (NTRS)

Many of the operational and payload lighting units used in various spacecraft contain elemental mercury. If these devices were damaged on-orbit, elemental mercury could be released into the cabin. Although there are plans to replace operational units with alternate light sources, such as LEDs, that do not contain mercury, mercury-containing lamps efficiently produce high quality illumination and may never be completely replaced on orbit. Therefore, exposure to elemental mercury during spaceflight will remain possible and represents a toxicological hazard. Elemental mercury is a liquid metal that vaporizes slowly at room temperature. However, it may be completely vaporized at the elevated operating temperatures of lamps. Although liquid mercury is not readily absorbed through the skin or digestive tract, mercury vapors are efficiently absorbed through the respiratory tract. Therefore, the amount of mercury in the vapor form must be estimated. For mercury releases from lamps that are not being operated, we utilized a study conducted by the New Jersey Department of Environmental Quality to calculate the amount of mercury vapor expected to form over a 2-week period. For longer missions and for mercury releases occurring when lamps are operating, we conservatively assumed complete volatilization of the available mercury. Because current spacecraft environmental control systems are unable to remove mercury vapors, both short-term and long-term exposures to mercury vapors are possible. Acute exposure to high concentrations of mercury vapors can cause irritation of the respiratory tract and behavioral symptoms, such as irritability and hyperactivity. Chronic exposure can result in damage to the nervous system (tremors, memory loss, insomnia, etc.) and kidneys (proteinurea). Therefore, the JSC Toxicology Group recommends that stringent safety controls and verifications (vibrational testing, etc.) be applied to any hardware that contains elemental mercury that could yield airborne mercury vapor concentrations greater than 0.1 mg/cu m in the total spacecraft atmosphere for exposures lasting 30 days or less or 0.01 mg/cu m mercury vapor for exposures lasting more than 30 days. We also encourage the use of alternative devices that do not contain mercury.

Meyers, Valerie E.; McCoy, J. Torin; Garcia, Hector D.; James, John T.

2009-01-01

327

Phytoremediation of ionic and methyl mercury pollution  

SciTech Connect

'The long-term objective of the research is to manipulate single-gene traits into plants, enabling them to process heavy metals and remediate heavy-metal pollution by resistance, sequestration, removal, and management of these contaminants. The authors are focused on mercury pollution as a case study of this plant genetic engineering approach. The working hypothesis behind this proposal was that transgenic plants expressing both the bacterial organo mercury lyase (merB) and the mercuric ion reductase gene (merA) will: (A) remove the mercury from polluted sites and (B) prevent methyl mercury from entering the food chain. The results from the research are so positive that the technology will undoubtedly be applied in the very near future to cleaning large mercury contaminates sites. Many such sites were not remediable previously due to the excessive costs and the negative environmental impact of conventional mechanical-chemical technologies. At the time this grant was awarded 20 months ago, the authors had successfully engineered a small model plant, Arabidopsis thaliana, to use a highly modified bacterial mercuric ion reductase gene, merA9, to detoxify ionic mercury (Hg(II)), reducing it to much less toxic and volatile metallic Hg(0) (Rugh et al., 1996). Seeds from these plants germinate, grow, and set seed at normal growth rates on levels of Hg(II) that are lethal to normal plants. In assays on transgenic seedlings suspended in a solution of Hg(II), 10 ng of Hg(0) was evolved per min per mg wet weight of plant tissue. At that time, the authors had no information on expression of merA in any other plant species, nor had the authors tested merB in any plant. However, the results were so startlingly positive and well received that they clearly presaged a paradigm shift in the field of environmental remediation.'

Meagher, R.B.

1998-06-01

328

Prognostic value of tissue and circulating levels of IMP3 in prostate cancer.  

PubMed

Tissue levels of the oncofetal protein insulin-like growth factor 2 (IGF2) messenger RNA-binding protein 3 (IMP3) have been associated with poor prognosis in multiple human malignancies. However, its circulating levels have not yet been analyzed. Therefore, the aim of this study was to assess the prognostic value of both serum and tissue levels of IMP3 in prostate cancer (PC). IMP3 protein expression was analyzed in 124 PC and 13 benign prostate hyperplasia (BPH) patients using immunohistochemistry. Gene expression levels of IMP3 and its molecular target IGF2 were analyzed in 29 frozen and 26 paraffin-embedded PC tissues using real-time polymerase chain reaction and immunohistochemistry. Serum IMP3 levels were assessed in 94 PC and 20 BPH patients as well as in 20 controls using enzyme-linked immunosorbent assay. IMP3 immunostaining was present in 0% (0/13) of BPHs, 15% (15/101) of clinically localized PCs and 65% (15/23) of palliatively treated metastatic PCs (p < 0.001). Accordingly, serum IMP3 concentrations were significantly higher in PC compared to BPH patients which were higher than those in controls (p < 0.001 each). The highest concentrations were detected in metastatic PC patients (p = 0.036). In patients who underwent radical prostatectomy high IMP3 serum levels were independently associated with poor cancer-specific survival. IMP3 gene and protein expressions were not correlated with those of IGF2. In conclusion, we found enhanced IMP3 levels in tissue and serum samples of PC patients compared to non-PC men. Moreover, IMP3 was associated with metastasis and PC-specific survival. The tumor promoting effect of IMP3 appears to be independent from its regulatory role on IGF2 in PC. PMID:24615121

Szarvas, Tibor; Tschirdewahn, Stephan; Niedworok, Christian; Kramer, Gero; Sevcenco, Sabina; Reis, Henning; Shariat, Shahrokh F; Rübben, Herbert; vom Dorp, Frank

2014-10-01

329

Quantification of Chitinase mRNA Levels in Human and Mouse Tissues by Real-Time PCR: Species-Specific Expression of Acidic Mammalian Chitinase in Stomach Tissues  

PubMed Central

Chitinase hydrolyzes chitin, which is an N-acetyl-D-glucosamine polymer that is present in a wide range of organisms, including insects, parasites and fungi. Although mammals do not contain any endogenous chitin, humans and mice express two active chitinases, chitotriosidase (Chit1) and acidic mammalian chitinase (AMCase). Because the level of expression of these chitinases is increased in many inflammatory conditions, including Gaucher disease and mouse models of asthma, both chitinases may play important roles in the pathophysiologies of these and other diseases. We recently established a quantitative PCR system using a single standard DNA and showed that AMCase mRNA is synthesized at extraordinarily high levels in mouse stomach tissues. In this study, we applied this methodology to the quantification of chitinase mRNAs in human tissues and found that both chitinase mRNAs were widely expressed in normal human tissues. Chit1 mRNA was highly expressed in the human lung, whereas AMCase mRNA was not overexpressed in normal human stomach tissues. The levels of these mRNAs in human tissues were significantly lower than the levels of housekeeping genes. Because the AMCase expression levels were quite different between the human and mouse stomach tissues, we developed a quantitative PCR system to compare the mRNA levels between human and mouse tissues using a human-mouse hybrid standard DNA. Our analysis showed that Chit1 mRNA is expressed at similar levels in normal human and mouse lung. In contrast, the AMCase expression level in human stomach was significantly lower than that expression level observed in mouse stomach. These mRNA differences between human and mouse stomach tissues were reflecting differences in the chitinolytic activities and levels of protein expression. Thus, the expression level of the AMCase in the stomach is species-specific. PMID:23826286

Ohno, Misa; Togashi, Yuto; Tsuda, Kyoko; Okawa, Kazuaki; Kamaya, Minori; Sakaguchi, Masayoshi; Sugahara, Yasusato; Oyama, Fumitaka

2013-01-01

330

Mercury concentrations of fish, river water, and sediment in the Río Ramis-Lake Titicaca watershed, Peru  

Microsoft Academic Search

This study reports the first set of data on the concentration of mercury in muscle tissue of several varieties of fish from Lake Titicaca, including the pejerrey (Basilichthyes bonariensis), the carachi (Orestias), and 2 types of indigenous catfish (Trichomycterus). Approximately 27% of the pejerrey and 75% of the carachi exceeded the US EPA fish tissue-based water quality criterion level of

Christopher H. Gammons; Darell G. Slotton; Butch Gerbrandt; Willis Weight; Courtney A. Young; Richard L. McNearny; Eugenio Cámac; Ruben Calderón; Henri Tapia

2006-01-01

331

Mercury, lead, and cadmium in blue crabs, Callinectes sapidus, from the Atlantic coast of Florida, USA: a multipredator approach.  

PubMed

Blue crabs, Callinectes sapidus, from the Atlantic coast of Florida were analyzed for total mercury, methylmercury, lead, and cadmium. Paired samples of two tissue types were analyzed for each crab, (1) muscle tissue (cheliped and body muscles) and (2) whole-body tissue (all organs, muscle tissue and connective tissue), for evaluation of the concentration of metals available to human consumers as well as estuarine predators. There were clear patterns of tissue-specific partitioning for each metal. Total mercury was significantly greater in muscle tissue (mean=0.078 µg/g) than in whole-body tissue (mean=0.055 µg/g). Conversely, whole-body concentrations of lead and cadmium (means=0.131 and 0.079 µg/g, respectively) were significantly greater than concentrations in muscle (means=0.02 and 0.029 µg/g, respectively). There were no significant correlations between any metal contaminant and crab size. Cadmium levels were significantly greater in the muscle tissue of females, but, no other sex-related differences were seen for other metals or tissue types. Methylmercury composed 93-100% of the total mercury in tissues. Compared to previous blue crab studies from different regions of the United States, mean concentrations of mercury, lead, and cadmium were relatively low, although isolated groups or individual blue crabs accumulated high metal concentrations. PMID:24507459

Adams, Douglas H; Engel, Marc E

2014-04-01

332

Regulation of Potassium Transport in Leaves: from Molecular to Tissue Level  

PubMed Central

Over millions of years, plants have evolved a sophisticated network of K+ transport systems. This Botanical Briefing provides an overview of K+ transporters in various leaf tissues (epidermis, mesophyll, guard cells and vascular system) at both the cellular and organelle levels. Despite the tremendous progress in our knowledge of genes encoding K+ transport systems in plants, understanding has not developed of coordinated functioning and operation of these genes or proteins in the context of whole plant physiology and plant–environment interaction. This Botanical Briefing is aimed at filling that gap by analysing electrophysiological and molecular evidence for mechanisms coordinating K+ transport between various leaf cells and tissues in changing environments. PMID:14500326

SHABALA, SERGEY

2003-01-01

333

THERMODYNAMIC REACTION CONSTANTS FOR MODELING AQUEOUS ENVIRONMENTAL MERCURY SPECIATION  

EPA Science Inventory

Unacceptably high fish tissue mercury residues are responsible for the majority of fish consumption advisories issued in 48 states of the United States of America. Mercury also has emerged as a transboundary contaminant of global concern. Although monomethylmercury is generally...

334

Mercury Accumulation and Biomagnification in Ospreys (Pandion haliaetus) in the James Bay and Hudson Bay Regions of Québec  

PubMed

Mercury exposure was examined in adults and nestlings of ospreys (Pandion haliaetus) from lakes, rivers, and hydroelectric reservoirs in northern Québec between 1989 and 1991 by assessing the amount of mercury transferred from fish to ospreys, which are voracious fish-eaters. The high mercury concentrations detected in adult feathers and tissues (feathers, blood, liver, kidneys, muscles, brain) of nestlings indicate an increase in mercury availability at recently constructed hydroelectric reservoirs (10-12 years for the La Grande-2 Reservoir). With mean total mercury levels of 37.3 mg/kg and 1.9 mg/kg in feathers (dry weight) and in blood (wet weight), respectively, contamination rates were, in both tissues, five times higher for chicks born near the La Grande Reservoirs (western sector) than in those reared in natural habitats. Furthermore, the mean quantity of total mercury in 40-day-old chicks reared near a reservoir was 10.5 mg, compared with to 1.6 mg for those reared in a natural environment. Modeling of mercury transfer from fish to osprey nestlings showed that the mercury level in chicks' blood provides a good estimate of mercury concentrations in ingested food. In addition, the relationship between mercury concentrations in the blood and that in feathers indicates that substantial biomagnification of mercury occurs from the ingested dose to the feathers. The intensity of this biomagnification varies with the age of the chicks and reaches a maximum value as the flight feathers start to form (at 20-25 days of age) declining thereafter until the bird is 45 days old and growth of those feathers is complete. Nevertheless, the mean number of young fledged on reservoirs where mercury exposure is greatest (>40 mg/kg of Hg in chicks' feathers) did not differ (1.6 +/- 0.7) from that observed elsewhere in built-up environments (1.9 +/- 0.7) or in natural habitats (2.0 +/- 0.7) (H = 4.39; p = 0.11). Storage of mercury in growing feathers (86% of all mercury in osprey) prevents accumulation in living tissues, thereby protecting the chick from related toxic effects. However, toxicological problems may arise after fledging. In particular, attention should be paid to postfledging survival before concluding that mercury exposure is insufficiently high in Osprey young reared at reservoirs. PMID:9680526

DesGranges; Rodrigue; Tardif; Laperle

1998-08-01

335

Increased levels of serum tissue inhibitor of metalloproteinase-1 but not metalloproteinase-3 in atopic dermatitis  

PubMed Central

Matrix metalloproteinases and their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs), contribute to inflammation-induced tissue destruction and subsequent remodeling for maintenance of tissue homeostasis. Since the production of these enzymes and their inhibitors is regulated by mediators such as proinflammatory cytokines and growth factors, elevated levels of serum TIMPs and/or MMPs have been documented in patients with several inflammatory disorders. In this study, we examined the role of TIMPs and MMPs in the pathogenesis of atopic dermatitis (AD) by evaluating the serum levels of TIMP-1 and MMP-3 in 40 patients with AD and 20 control subjects by ELISA. The serum TIMP-1 levels were significantly higher in AD patients in exacerbation status than in nonatopic subjects, whereas serum MMP-3 levels were not significantly different between them. As a result, AD patients revealed significantly elevated TIMP-1/MMP-3 ratios. The levels of serum TIMP-1 were significantly reduced in AD patients following conventional treatments. Significantly higher values of peripheral eosinophil counts, serum levels of IgE and lactate dehydrogenase, eruption score, and eruption area were noted in the AD patients with elevated TIMP-1 levels when compared with those with normal values. Moreover, the points of chronic eruptions such as lichenification and prurigo were significantly higher in the patients with elevated TIMP-1 levels than those with normal TIMP-1, while those of acute lesions such as oozy/microvesicles and oedema were not different between these groups. Serum TIMP-1 level may be a useful marker to estimate the long-term disease activity of AD. PMID:11876751

KATOH, N; HIRANO, S; SUEHIRO, M; IKENAGA, K; YASUNO, H

2002-01-01

336

Blood levels of lead, cadmium, and mercury in the Korean population: Results from the Second Korean National Human Exposure and Bio-monitoring Examination  

SciTech Connect

In Korea, there have been a number of efforts to measure levels of exposure to environmental pollutants among the population. This paper focuses on investigating the distribution of, extent of, and factors influencing the blood levels of lead, cadmium, and mercury in the Korean population, working from data obtained from the Second Korean National Human Exposure and Bio-monitoring Examination. To that end, blood metal concentrations were analyzed from a total of 2369 participants who were 18 years of age and older. The geometric mean concentrations and their 95% confidence intervals of metals in blood were found to be lead, 1.72 {mu}g/dL (95% CI, 1.68-1.76); cadmium, 1.02 {mu}g/L (95% CI, 1.00-1.05); and mercury, 3.80 {mu}g/L (95% CI, 3.66-3.93). Regression analyses indicate that the levels of metals in the blood are mainly influenced by gender, age, and the education levels of the participants. Current smoking status is also found to be a significant factor for increasing both lead and cadmium levels. Although our study, as the first nationwide survey of exposure to environmental pollutants in Korea, has value on its own, it should be expanded and extended in order to provide information on environmental exposure pathways and to watch for changes in the level of exposure to environmental pollutants among the population.

Son, Ji-Young [Department of Public Health, Graduate School of Hanyang University, Hanyang University, Seoul (Korea, Republic of)] [Department of Public Health, Graduate School of Hanyang University, Hanyang University, Seoul (Korea, Republic of); Lee, Jinheon [Department of Environmental Education, Kongju National University (Korea, Republic of)] [Department of Environmental Education, Kongju National University (Korea, Republic of); Paek, Domyung [Department of Environmental Health, School of Public Health, Seoul National University, Seoul (Korea, Republic of)] [Department of Environmental Health, School of Public Health, Seoul National University, Seoul (Korea, Republic of); Lee, Jong-Tae, E-mail: jtlee@korea.ac.kr [Department of Environmental Health, College of Health Science, Korea University, San 1 Jeongreung-dong, Seongbuk-gu, Seoul, Korea 136-703 (Korea, Republic of)] [Department of Environmental Health, College of Health Science, Korea University, San 1 Jeongreung-dong, Seongbuk-gu, Seoul, Korea 136-703 (Korea, Republic of)

2009-08-15

337

Critical levels of atmospheric pollution: criteria and concepts for operational modelling of mercury in forest and lake ecosystems  

Microsoft Academic Search

Mercury (Hg) is regarded as a major environmental concern in many regions, traditionally because of high concentrations in freshwater fish, and now also because of potential toxic effects on soil microflora. The predominant source of Hg in most watersheds is atmospheric deposition, which has increased 2- to >20-fold over the past centuries. A promising approach for supporting current European efforts

Markus Meili; Kevin Bishop; Lage Bringmark; Kjell Johansson; John Munthe; Harald Sverdrup; Wim de Vries

2003-01-01

338

Cholinesterase and monoamine oxidase activity in relation to mercury levels in the cerebral cortex of wild river otters  

Microsoft Academic Search

Mercury (Hg) is a global pollutant that is neurotoxic to many mammalian species. The present study was conducted to determine if the bioaccumulation of Hg by wild river otters (Lontra canadensis) could be related to variations in the activities of key neurochemical enzymes. River otters were collected from Ontario and Nova Scotia (Canada) during the trapping seasons, spanning 2002-2004, and

N Basu; A M Scheuhammer; R D Evans; M OBrien; H M Chan

2007-01-01

339

Blood Levels of Mercury Are Related to Diagnosis of Autism: A Reanalysis of an Important Data Set  

Microsoft Academic Search

The question of what is leading to the apparent increase in autism is of great importance. Like the link between aspirin and heart attack, even a small effect can have major health implications. If there is any link between autism and mercury, it is absolutely crucial that the first reports of the question are not falsely stating that no link

M. Catherine DeSoto; Robert T. Hitlan

2007-01-01

340

Chemical Form Matters: Differential Accumulation of Mercury Following Inorganic and Organic Mercury Exposures in Zebrafish Larvae  

SciTech Connect

Mercury, one of the most toxic elements, exists in various chemical forms each with different toxicities and health implications. Some methylated mercury forms, one of which exists in fish and other seafood products, pose a potential threat, especially during embryonic and early postnatal development. Despite global concerns, little is known about the mechanisms underlying transport and toxicity of different mercury species. To investigate the impact of different mercury chemical forms on vertebrate development, we have successfully combined the zebrafish, a well-established developmental biology model system, with synchrotron-based X-ray fluorescence imaging. Our work revealed substantial differences in tissue-specific accumulation patterns of mercury in zebrafish larvae exposed to four different mercury formulations in water. Methylmercury species not only resulted in overall higher mercury burdens but also targeted different cells and tissues than their inorganic counterparts, thus revealing a significant role of speciation in cellular and molecular targeting and mercury sequestration. For methylmercury species, the highest mercury concentrations were in the eye lens epithelial cells, independent of the formulation ligand (chloride versus L-cysteine). For inorganic mercury species, in absence of L-cysteine, the olfactory epithelium and kidney accumulated the greatest amounts of mercury. However, with L-cysteine present in the treatment solution, mercuric bis-L-cysteineate species dominated the treatment, significantly decreasing uptake. Our results clearly demonstrate that the common differentiation between organic and inorganic mercury is not sufficient to determine the toxicity of various mercury species.

Korbas, Malgorzata; MacDonald, Tracy C.; Pickering, Ingrid J.; George, Graham N.; Krone, Patrick H. (Saskatchewan)

2013-04-08

341

High levels of polychlorinated biphenyls in tissues of Atlantic turtles stranded in the Canary Islands, Spain.  

PubMed

Polychlorinated biphenyls (PCBs 28, 31, 52, 101, 138, 153, 180, and 209) were measured in tissue samples (liver and fat) from 30 loggerhead turtles Caretta caretta, 1 green turtle Chelonia mydas, and 1 leatherback Dermochelys coriacea stranded on the coasts of the Canary Islands, trying to establish a possible relation between PCB concentrations and the lesions and causes of death. Tissues from these turtles contained higher levels of PCBs than those reported in turtles from other geographical regions. Sigma PCB concentrations (1980+/-5320 ng g(-1)wet wt.) in the liver of loggerheads were higher than in the adipose tissue (450+/-1700 ng g(-1)wet wt.). Concentrations of PCB 209 in the liver (1200+/-3120 ng g(-1)wet wt.) of loggerheads and in the liver (530 ng g(-1)wet wt.) and adipose tissue (500 ng g(-1)wet wt.) of the leatherback were remarkable. Frequencies of detection of PCB 209 in the liver (15.5%) and adipose tissue (31%) were also remarkable. Cachexia was detected in 7 turtles (22%) and septicemia was diagnosed in 10 turtles (31%). Statistically, a positive correlation was detected between Sigma PCBs concentration and cachexia. Poor physical condition, cachexia and/or septicaemia could explain the high levels of PCBs and tissue distribution. However, no histological lesions exclusively attributed to the acute effects of PCBs were described. The most prevalent histological lesions were ulcerative and purulent oesophagitis, purulent dermatitis, necrotizing enteritis, and granulomatous pneumonia. The bacteria most frequently isolated were Escherichia coli, Staphylococcus sp., and Aeromonas sp. Although immunosupression as a result of PCBs pollution has been described previously, other factors in this study, such as incidental fishing, nutritional status, and exposition to different micro-organisms, make it difficult to establish a clear association between PCB concentrations and causes of death. PMID:19062067

Orós, J; González-Díaz, O M; Monagas, P

2009-01-01

342

Precise optical dosimetry in low-level laser therapy of soft tissues in oral cavity  

NASA Astrophysics Data System (ADS)

The new low level laser therapy (LLLT) is widely applied for treatment of diseases of the oral mucosa and parodont. Depending on indication, different optical tips and light-guides are used to create beams with a required shape. However, to the best of our knowledge, the developed irradiation geometries are usually proposed assuming validity of Bouger-Lambert law. This hardly corresponds to the real situation because of the dominating multiple scattering within 600-1200 nm range that destroys correlation between the emitted laser beam and the spatial distribution of the absorbed dose inside the tissue. The aim of this work is to base the dosimetry of the LLLT procedures of periodontal tissues on radiation transfer theory using a flexible Monte-Carlo code. We studied quantitatively the influence of tissue optical parameters (absorption and scattering coefficients, tissue refraction index, anisotropy factor) on decreasing of correlation between the emitted beam and the energy deposition for converging or diverging beams. We evaluated energy deposition for the developed by us LLLT system in a 3-D model of periodontal tissues created using a cross-sectional image of this region with internal structural information on the gingival and the tooth. The laser source is a CW diode laser emitting elliptical beam within 650-675 nm at output power 5-30 mW. To determine the geometry of the irradiating beam we used CCD camera Spiricon LBA 300.

Stoykova, Elena V.; Sabotinov, O.

2004-06-01

343

Obesity And Laboratory Diets Affects Tissue Malondialdehyde (MDA) Levels In Obese Rats  

NASA Astrophysics Data System (ADS)

This study was conducted to investigate the interaction of obesity and laboratory diets on tissue malondialdehyde levels in rats. Female Zucker obese and lean rats were maintained on either regular grain-based diet or purified casein diet for two weeks, orally gavaged at day 50 with 65 mg/kg DMBA and sacrificed 24 hrs later. Malondialdehyde (MDA) levels were measured in blood and harvested tissues. Data were recorded as mean ± SEM and analyzed statistically. Results show that the obese group on purified casein diet had reduction of MDA levels in the brain, duodenum, liver, lung and kidney tissues as compared to lean group, p <0.05. Obese group on grain-based diet showed significant increase in MDA levels only in the duodenum, p <0.05. We conclude that dietary intervention differentially affects the oxidative markers in obese rats. It appears that purified casein diets were more effective than grain-based diet in reduction of oxidative stress in obese rats.

Chowdhury, Parimal; Scott, Joseph; Holley, Andy; Hakkak, Reza

2010-04-01

344

Human exposure to metals: levels in autopsy tissues of individuals living near a hazardous waste incinerator.  

PubMed

The concentrations of a number of metals were determined in the brain, bone, kidney, liver, and lung of 20 autopsied subjects who had lived, at least 10 years, in the neighborhood of a hazardous waste incinerator (HWI) in Tarragona (Catalonia, Spain). Results were compared with those obtained in 1998 (baseline survey) and previous surveys (2003 and 2007). Arsenic, Be, Ni, Tl, and V showed concentrations below the corresponding detection limits in all tissues. Cadmium showed the highest levels in the kidney, with a mean value of 21.15 ?g/g. However, Cd was found below the detection limit in the brain and bone. Chromium showed similar concentrations in the kidney, brain, and lung (range of mean values, 0.57-0.66 ?g/g) and higher in the bone (1.38 ?g/g). In turn, Hg was below the detection limit in all tissues with the exception of the kidney, where the mean concentration was 0.15 ?g/g (range, <0.05-0.58 ?g/g). On the other hand, Mn could be detected in all tissues showing the highest levels in the liver and kidney (1.45 and 1.09 ?g/g, respectively). Moreover, Pb showed the highest concentrations in bone (mean, 1.39 ?g/g; range, <0.025-4.88 ?g/g). Finally, Sn could be detected only in some tissue samples, reaching the highest values in the bone (0.17 ?g/g). The current metal levels in human tissues from individuals living near the HWI of Tarragona are comparable and of a similar magnitude to previously reported results corresponding to general populations, as well as those of our previous surveys. PMID:24728924

Mari, Montse; Nadal, Martí; Schuhmacher, Marta; Barbería, Eneko; García, Francisco; Domingo, José L

2014-06-01

345

Historical and other patterns of monomethyl and inorganic mercury in the Florida panther (Puma concolor coryi).  

PubMed

Since the late 1980s, elevated levels of mercury have been reported in the tissues of the Florida panther (Puma concolor coryi) from the Florida Everglades. The extent, degree, and length of time of mercury contamination in the Florida panther are unknown. The objective of this study was to determine the historical and other patterns of monomethyl and inorganic mercury in the Florida panther by analysis of mercury in panther hair from museum collections. In addition, this study evaluated the effects of preservation of skins on mercury concentrations in hair and the representativeness of museum collections for evaluating historical trends of contamination in the Florida panther. Hair from 42 Florida panther specimens collected from 1896 to 1995 was analyzed for both monomethyl and inorganic mercury. Monomethyl mercury (MMHg) and inorganic mercury (IHg) were found in all specimens. Monomethyl mercury in hair from untanned skins was significantly higher than MMHg in hair from tanned skins. For untanned specimens, the mean MMHg concentration in hair was 1.62 +/- 1.87 mug/g (range 0.11 to 6.68 mug/g, n = 16). Monomethyl mercury accounted for 88% of the total mercury in untanned Florida panther hair. No sexual or geographical differences were found. Although MMHg is generally stable in hair, the tanning process appears to reduce the amount of MMHg in hair. In addition, exogenous IHg contamination of the panther hair was found in museum specimens, especially in older specimens. The implication of these and other factors in interpreting results of museum studies is discussed. The presence of MMHg in panther hair since the 1890s indicates long-term and widespread exposure of the Florida panther to mercury. Levels of MMHg are significantly greater in the 1990s than the 1890s. When combined with field studies of mercury in the Florida panther, considerable individual variability is observed, reflecting short-term changes in exposure of individual panthers to mercury. Although museum specimens showed a significant increase in MMHg over the last 100 years, they did not show the magnitude of increase that field populations of Florida panthers did. A number of Florida panthers appeared to be at risk from mercury over their lifetimes, especially individuals from the early 1990s. PMID:15657808

Newman, J; Zillioux, E; Rich, E; Liang, L; Newman, C

2005-01-01

346

A comparative study of diazepam levels in bone marrow versus serum, saliva and brain tissue.  

PubMed

The distribution of diazepam in biological fluids and tissues of rats was examined 1, 2, 4 and 8 h after intraperitoneal administration by using a radioimmunoassay with specific anti-diazepam antibody. The diazepam levels in serum, saliva, brain and bone marrow decreased over a period of 2 h and levelled off 4 h after administration. The diazepam concentration in bone marrow was much higher than in serum, saliva and brain, suggesting an accumulation of diazepam in this tissue. This indicates that bone marrow could be a very useful material for the detection of diazepam in skeletonized remains. The diazepam concentrations in bone marrow, serum, saliva and brain showed a linear relationship (r = 0.860-0.997), indicating that a valid estimate of diazepam concentration in blood can be made from bone marrow samples. PMID:1931735

Takatori, T; Tomii, S; Terazawa, K; Nagao, M; Kanamori, M; Tomaru, Y

1991-01-01

347

DNA adduct level in lung tissue may act as a risk biomarker of lung cancer  

Microsoft Academic Search

Lung cancer is a leading cause of mortality in Taiwan. We hypothesised that high susceptibility to DNA damage in the target organ acts as a risk biomarker for the development of lung cancer. To verify this hypothesis, the aromatic\\/hydrophobic DNA adduct levels of non-tumorous adjacent lung tissues from 73 primary lung cancer patients and 33 non-cancer controls were evaluated by

Y.-W Cheng; C.-Y Chen; P Lin; C.-P Chen; K. H Huang; T.-S Lin; M.-H Wu; H Lee

2000-01-01

348

Decreasing aqueous mercury concentrations to achieve safe levels in fish: examining the water-fish relationship in two point-source contaminated streams  

SciTech Connect

East Fork Poplar Creek (EFPC) and White Oak Creek (WOC) are two mercury-contaminated streams located on the Department of Energy s Oak Ridge Reservation in east Tennessee. East Fork Poplar Creek is the larger and more contaminated of the two, with average aqueous mercury (Hg) concentrations exceeding those in reference streams by several hundred-fold. Remedial actions over the past 20 years have decreased aqueous Hg concentrations in EFPC by 85 %. Fish fillet concentrations, however, have not responded to this decrease in aqueous Hg and remain above the U.S. Environmental Protection Agency s ambient water quality criterion (AWQC) of 0.3 mg/kg. The lack of correlation between aqueous and fish tissue Hg concentrations in this creek has led to questions regarding the usefulness of target aqueous Hg concentrations and strategies for future remediation efforts. White Oak Creek has a similar contamination history but aqueous Hg concentrations in WOC are an order of magnitude lower than in EFPC. Despite the lower aqueous Hg concentrations, fish fillet concentrations in WOC have also been above the AWQC, making the most recent aqueous Hg target of 200 ng/L in EFPC seem unlikely to result in an effective decrease in fillet Hg concentrations. Recent monitoring efforts in WOC, however, suggest an aqueous total Hg threshold above which Hg bioaccumulation in fish may not respond. This new information could be useful in guiding remedial actions in EFPC and in other point-source contaminated streams.

Mathews, Teresa J [ORNL; Southworth, George R [ORNL; Peterson, Mark J [ORNL; Roy, W Kelly [ORNL; Ketelle, Richard H [ORNL; Valentine, Charles S [ORNL; Gregory, Scott M [ORNL

2013-01-01

349

Critical levels of atmospheric pollution: criteria and concepts for operational modelling of mercury in forest and lake ecosystems.  

PubMed

Mercury (Hg) is regarded as a major environmental concern in many regions, traditionally because of high concentrations in freshwater fish, and now also because of potential toxic effects on soil microflora. The predominant source of Hg in most watersheds is atmospheric deposition, which has increased 2- to >20-fold over the past centuries. A promising approach for supporting current European efforts to limit transboundary air pollution is the development of emission-exposure-effect relationships, with the aim of determining the critical level of atmospheric pollution (CLAP, cf. critical load) causing harm or concern in sensitive elements of the environment. This requires a quantification of slow ecosystem dynamics from short-term collections of data. Aiming at an operational tool for assessing the past and future metal contamination of terrestrial and aquatic ecosystems, we present a simple and flexible modelling concept, including ways of minimizing requirements for computation and data collection, focusing on the exposure of biota in forest soils and lakes to Hg. Issues related to the complexity of Hg biogeochemistry are addressed by (1) a model design that allows independent validation of each model unit with readily available data, (2) a process- and scale-independent model formulation based on concentration ratios and transfer factors without requiring loads and mass balance, and (3) an equilibration concept that accounts for relevant dynamics in ecosystems without long-term data collection or advanced calculations. Based on data accumulated in Sweden over the past decades, we present a model to determine the CLAP-Hg from standardized values of region- or site-specific synoptic concentrations in four key matrices of boreal watersheds: precipitation (atmospheric source), large lacustrine fish (aquatic receptor and vector), organic soil layers (terrestrial receptor proxy and temporary reservoir), as well as new and old lake sediments (archives of response dynamics). Key dynamics in watersheds are accounted for by quantifying current states of equilibration in both soils and lakes based on comparison of contamination factors in sediment cores. Future steady-state concentrations in soils and fish in single watersheds or entire regions are then determined by corresponding projection of survey data. A regional-scale application to southern Sweden suggests that the response of environmental Hg levels to changes in atmospheric Hg pollution is delayed by centuries and initially not proportional among receptors (atmosphere > soils not equal sediments>fish; clearwater lakes > humic lakes). This has implications for the interpretation of common survey data as well as for the implementation of pollution control strategies. Near Hg emission sources, the pollution of organic soils and clearwater lakes deserves attention. Critical receptors, however, even in remote areas, are humic waters, in which biotic Hg levels are naturally high, most likely to increase further, and at high long-term risk of exceeding the current levels of concern:

Meili, Markus; Bishop, Kevin; Bringmark, Lage; Johansson, Kjell; Munthe, John; Sverdrup, Harald; de Vries, Wim

2003-03-20

350

Soft Tissue Mobilization and PNF Improve Range of Motion and Minimize Pain Level in Shoulder Impingement  

PubMed Central

[Purpose] The aim of this study was to evaluate the effects of soft tissue mobilization and PNF on pain level, and shoulder ROM in patients with shoulder impingement syndrome. [Subjects and Methods] Thirty patients with painful and limited glenohumeral ROM activities were selected. The subjects were randomly assigned to an experimental group (n=15), which received treatment consisting of soft tissues mobilization and the PNF technique. The control group received an ultrasound treatment. Pain level, glenohumeral external rotation and overhead reach were measured before and after the intervention in groups. [Results] The experimental group showed a significant reduction in pain level in comparison with the control group. The values for Shoulder external rotation showed a significant improvement. The mean value for overhead reach in the experimental group significantly increased. [Conclusion] The combination of soft tissue mobilization for the subscapularis for 7 minutes and 5 repetitions of the contract-relax PNF technique for the shoulder internal rotator muscles followed by 5 repetitions of a PNF facilitated abduction and external rotation diagonal pattern was found to be effective in reducing pain and improving glenohumeral external rotation and overhead reach during a single intervention session.

Al Dajah, Salameh Bweir

2014-01-01

351

Epicardial adipose tissue thickness and NGAL levels in women with polycystic ovary syndrome  

PubMed Central

Background Polycystic ovary syndrome (PCOS) is associated with an increased cardiovascular disease (CVD) risk and early atherosclerosis. Epicardial adipose tissue thickness (EATT) is clinically related to subclinical atherosclerosis. In the present study, considering the major role of neutrophil gelatinase-associated lipocalin (NGAL) which is an acute phase protein rapidly releasing upon inflammation and tissue injury, we aimed to evaluate NGAL levels and EATT in PCOS patients and assess their relationship with cardiometabolic factors. Methods 64 patients with PCOS and 50 age- and body mass index-matched healthy controls were included in the study. We evaluated anthropometric, hormonal and metabolic parameters. EATT was measured by echocardiography above the free wall of the right ventricle. Serum NGAL and high-sensitive C- reactive protein (hsCRP) levels were measured by ELISA. Results Mean EATT was 0,38 +/-0,16 mm in the PCOS group and 0,34 +/-0,36 mm in the control group (p?=?0,144). In the obese PCOS group (n?=?44) EAT was thicker compared to the obese control group (n?=?41) (p?=?0.026). Mean NGAL levels of the patients with PCOS were 101,98 +/-21,53 pg/ml, while mean NGAL levels were 107,40 +/-26,44 pg/ml in the control group (p?=?0,228). We found a significant positive correlation between EATT and age, BMI, waist circumference, fasting insulin, HOMA-IR, triglyceride and hsCRP levels in PCOS group. Conclusions Thickness of the epicardial adipose tissue can be used to follow the risk of CVD development in obese PCOS cases. However serum NGAL levels do not differ in patients with PCOS and control group. PMID:24528623

2014-01-01

352

Regional Adipose Tissue and Lipid and Lipoprotein Levels in HIV-Infected Women  

PubMed Central

Background HIV infection and antiretroviral therapy are associated with dyslipidemia, but the association between regional body fat and lipid levels is not well described. Methods Multivariable linear regression analyzed the association between magnetic resonance imaging–measured regional adipose tissue and fasting lipids in 284 HIV-infected and 129 control women. Results Among African Americans, HIV-infected women had higher triglyceride (116 vs. 83 mg/dL; P < 0.001), similar high-density lipoprotein (HDL; 52 vs. 50 mg/dL; P = 0.60), and lower low-density lipoprotein (LDL; 99 vs. 118 mg/dL; P = 0.008) levels than controls. Among whites, HIV-infected women had higher triglyceride (141 vs. 78 mg/dL; P < 0.001), lower HDL (46 vs. 57 mg/dL; P < 0.001), and slightly lower LDL (100 vs. 107 mg/dL; P = 0.059) levels than controls. After adjustment for demographic and lifestyle factors, the highest tertile of visceral adipose tissue (VAT) was associated with higher triglyceride (+85%, 95% confidence interval [CI]: 55 to 121) and lower HDL (?9%, 95% CI: ?18 to 0) levels in HIV-infected women; the highest tertile of leg subcutaneous adipose tissue (SAT) was associated with lower triglyceride levels in HIV-infected women (?28%, 95% CI: ?41 to ?11) and controls (?39%, 95% CI: ?5 to ?18). After further adjustment for adipose tissue, HIV infection remained associated with higher triglyceride (+40%, 95% CI: 21 to 63) and lower LDL (?17%, 95% CI: ?26 to ?8) levels, whereas HIV infection remained associated with lower HDL levels (?21%, 95% CI: ?29 to ?12) in whites but not in African Americans (+8%, 95% CI: ?2 to 19). Conclusions HIV-infected white women are more likely to have proatherogenic lipid profiles than HIV-infected African American women. Less leg SAT and more VAT are important factors associated with adverse lipid levels. HIV-infected women may be at particular risk for dyslipidemia because of the risk for HIV-associated lipoatrophy. PMID:18197118

Currier, Judith; Scherzer, Rebecca; Bacchetti, Peter; Heymsfield, Steven; Lee, Daniel; Sidney, Stephen; Tien, Phyllis C.

2009-01-01

353

Bioaccumulation and biomagnification of total mercury in four exploited shark species in the Baja California Peninsula, Mexico.  

PubMed

The present study determined the average mercury bioaccumulation in the muscle tissue of four shark species (Carcharhinus falciformis, Prionace glauca, Sphyrna zygaena and Isurus oxyrinchus) captured in the Baja California Peninsula. We also evaluated biomagnification of some prey consumed by sharks. All sharks' species had mercury levels over the limit specified by the Mexican government for human consumption. Blue shark (P. glauca) presented highest mercury values (1.96 ± 1.48 ?g/g Hg d.w.) and it was the unique specie that showed a negative correlation with mercury content (Rs = -0.035, p = 0.91). Scomber japonicus was the prey with high content of mercury (0.57 ± 0.02 ?g/g). PMID:22187022

Maz-Courrau, A; López-Vera, C; Galván-Magaña, F; Escobar-Sánchez, O; Rosíles-Martínez, R; Sanjuán-Muñoz, A

2012-02-01

354

Mercury residues in free-grazing cattle and domestic fowl form the artisanal gold mining area of Geita district, Tanzania.  

PubMed

Environmental contamination with mercury from artisanal gold mines in Tanzania has been widely reported. People living around mining villages keep domestic animals which are allowed to feed freely in mercury-contaminated areas. This study investigated Hg accumulation in the liver and muscle tissue of cattle and domestic fowl reared in mining villages. Total mercury levels up to 436 and 820 microg/kg wet weight were found in liver samples taken from cattle and domestic fowl, respectively. Significantly higher mercury concentrations were found in liver samples collected at mining villages (p<0.05) than those taken from the reference area. While mercury concentrations in liver samples exceeded the acceptable maximum concentrations for humans set in the Netherlands and Poland, the Hg concentrations in muscle were below the limits of most countries. It is recommended that the keeping of freely grazing cattle and domestic fowl in or around artisanal gold mines should be avoided. PMID:19798780

Chibunda, R T; Janssen, C R

2009-11-01

355

Gill Na +,K +ATPase activity in largemouth bass ( Micropterus salmoides) from three reservoirs with different levels of mercury contamination  

Microsoft Academic Search

Exposure to high concentrations of dissolved mercury (Hg) causes gill pathologies and interferes with ion and osmoregulation in fish. Although the gill ion-exchange enzyme Na+,K+-ATPase is inhibited by Hg in laboratory experiments, the concentrations that produce such effects are much higher than normally found in natural waters. However, Stagg et al. (1992, Mar. Environ. Res., 33: 255–266) found a significant

Charles H. Jagoe; Patricia L. Shaw-Allen; Sandy Brundage

1996-01-01

356

A Comparison of Mercury Levels in Feathers and Eggs of Osprey ( Pandion haliaetus ) in the North American Great Lakes  

Microsoft Academic Search

.   Osprey (Pandion haliaetus) eggs and chick feathers were collected for mercury analysis from nests at four Great Lakes study areas in Ontario (three\\u000a “naturally formed” lakes in southern Ontario and one reservoir in northern Ontario) and two New Jersey study areas in 1991–1994.\\u000a Adult osprey feathers were sampled from three Great Lakes study areas in 1991. Feathers sampled from

K. D. Hughes; P. J. Ewins; K. E. Clark

1997-01-01

357

Reduced tissue-level stiffness and mineralization in osteoporotic cancellous bone.  

PubMed

Osteoporosis alters bone mass and composition ultimately increasing the fragility of primarily cancellous skeletal sites; however, effects of osteoporosis on tissue-level mechanical properties of cancellous bone are unknown. Dual-energy X-ray absorptiometry (DXA) scans are the clinical standard for diagnosing osteoporosis though changes in cancellous bone mass and mineralization are difficult to separate using this method. The goal of this study was to investigate possible difference in tissue-level properties with osteoporosis as defined by donor T scores. Spine segments from Caucasian female cadavers (58-92 years) were used. A T score for each donor was calculated from DXA scans to determine osteoporotic status. Tissue-level composition and mechanical properties of vertebrae adjacent to the scan region were measured using nanoindentation and Raman spectroscopy. Based on T scores, six samples were in the Osteoporotic group (58-74 years) and four samples were in the Not Osteoporotic group (65-92 years). The indentation modulus and mineral to matrix ratio (mineral:matrix) were lower in the Osteoporotic group than the Not Osteoporotic group. Mineral:matrix ratio decreased with age (r (2) = 0.35, p = 0.05), and the indentation modulus increased with areal bone mineral density (r (2) = 0.41, p = 0.04). This study is the first to examine cancellous bone composition and mechanical properties from a fracture prone location with osteoporosis. We found differences in tissue composition and mechanical properties with osteoporosis that could contribute to increased fragility in addition to changes in trabecular architecture and bone volume. PMID:24888692

Kim, Grace; Cole, Jacqueline H; Boskey, Adele L; Baker, Shefford P; van der Meulen, Marjolein C H

2014-08-01

358

Leptin secretion from adipose tissue in women. Relationship to plasma levels and gene expression.  

PubMed Central

The role of expression and secretion of the ob gene product, leptin, for the regulation of plasma leptin levels has been investigated in vitro using abdominal subcutaneous adipose tissue of 20 obese, otherwise healthy, and 11 nonobese women. Body mass index (BMI, mean+/-SEM; kg/m2) in the two groups was 41+/-2 and 23+/-1, respectively. Fat cell volume was 815+/-55 pl in the obese and 320+/-46 pl in the nonobese group. In the obese group, plasma leptin concentrations and adipose leptin mRNA (relative to gamma actin) were increased five and two times, respectively. Moreover, adipose tissue secretion rates per gram lipid weight or per fat cell number were also increased two and seven times, respectively, in the obese group. There were strong linear correlations (r = 0.6-0.8) between plasma leptin, leptin secretion, and leptin mRNA. All of these leptin measurements correlated strongly with BMI and fat cell volume (r = 0.7- 0.9). About 60% of the variation in plasma leptin could be attributed to variations in leptin secretion rate, BMI, or fat cell volume. We conclude that elevated circulating levels of leptin in obese women above all result from accelerated secretion rates of the peptide from adipose tissue because of increased ob gene expression. However, leptin mRNA, leptin secretion, and circulating leptin levels are all more closely related to the stored amount of lipids in the fat cells of adipose tissue than they are to an arbitrary division into obese versus nonobese. PMID:9153282

Lonnqvist, F; Nordfors, L; Jansson, M; Thorne, A; Schalling, M; Arner, P

1997-01-01

359

[Mercury concentration and its distribution in Nycticorax nycticorax and Chinese Ardeola bacchus fledglings at Huangpu District of Guangzhou City, China].  

PubMed

In this study, live fledglings of Nycticorax nycticorax and Ardeola bacchus at the Huangpu District of Guangzhou City were collected, and their primary feather, breast feather, tail feather, liver, chest muscle and egg shell were sampled for mercury determination. The results showed that these two heron species had a very similar distribution pattern of mercury concentration in their tissues and organs, i. e., tail feather > breast and primary feather > liver > chest muscle > egg shell. Ardeola bacchus had higher levels of mercury in all its tissues than Nycticorax nycticorax. There were significant interspecific differences in mercury level for breast feather and primary feather. Because the collection of breast feather is easier and not harmful to birds, it is better to use it rather than primary or tail feather to monitor environmental pollution. The mercury level in breast feather was ten times higher than that in liver, lower than that in tail feather, but not significantly different to that in primary feather. The mercury concentrations in the tissues of Nycticorax nycticorax and Ardeola bacchus from Huangpu District of Guangzhou were similar to those from the suburbs of Chengdu, Sichuan Province, but lower than those from Taihu Lake, Jiangsu Province and higher than those from Hong Kong. PMID:15852945

Zou, Fasheng; Yang, Qiongfang; Li, Yanhong; Cui, Kunyan

2005-02-01

360

Effect of metallothionein core promoter region polymorphism on cadmium, zinc and copper levels in autopsy kidney tissues from a Turkish population  

SciTech Connect

Metallothioneins (MTs) are metal-binding, low molecular weight proteins and are involved in pathophysiological processes like metabolism of essential metals, metal ion homeostasis and detoxification of heavy metals. Metallothionein expression is induced by various heavy metals especially cadmium, mercury and zinc; MTs suppress toxicity of heavy metals by binding themselves to these metals. The aim of this study was to investigate the association between the - 5 A/G metallothionein 2A (MT2A) single nucleotide polymorphism (SNP) and Cd, Zn and Cu levels in the renal cortex from autopsy cases. MT2A core promoter region - 5 A/G SNP was analyzed by PCR-RFLP method using 114 autopsy kidney tissues and the genotype frequencies of this polymorphism were found as 87.7% homozygote typical (AA), 11.4% heterozygote (AG) and 0.9% homozygote atypical (GG). In order to assess the Cd, Zn and Cu levels in the same autopsy kidney tissues, a dual atomic absorption spectrophotometer system was used and the average levels of Cd, Zn and Cu were measured as 95.54 {+-} 65.58 {mu}g/g, 181.20 {+-} 87.72 {mu}g/g and 17.14 {+-} 16.28 {mu}g/g, respectively. As a result, no statistical association was found between the - 5 A/G SNP in the MT2A gene and the Zn and Cu levels in the renal cortex (p > 0.05), but considerably high accumulation of Cd was monitored for individuals having AG (151.24 {+-} 60.21 {mu}g/g) and GG genotypes (153.09 {mu}g/g) compared with individuals having AA genotype (87.72 {+-} 62.98 {mu}g/g) (p < 0.05). These results show that the core promoter region polymorphism of metallothionein 2A increases the accumulation of Cd in human renal cortex.

Kayaalti, Zeliha, E-mail: kayaalti@medicine.ankara.edu.t [Ankara University Institute of Forensic Medicine, Institute of Forensic Medicine, Ankara University, Dikimevi, 06590, Ankara (Turkey); Mergen, Goerkem; Soeylemezoglu, Tuelin [Ankara University Institute of Forensic Medicine, Institute of Forensic Medicine, Ankara University, Dikimevi, 06590, Ankara (Turkey)

2010-06-01

361

Cadmium, zinc, copper, arsenic, selenium and mercury in seabirds from the Barents Sea: levels, inter-specific and geographical differences.  

PubMed

Trace elements Cd, Zn, Cu, As, Se and Hg were analysed in muscle and liver of Brünnich's guillemot, Common guillemot, Puffin, Black guillemot, Little auk, Razorbill, Common eider, King eider, Glaucous gull, Herring gull, Black-legged kittiwake, Northern fulmar and Arctic tern collected in 1991-1992 at the main breeding colonies in the Barents Sea. The highest levels of the most toxic elements Cd and Hg were found in birds nesting north of Spitsbergen. Extremely high levels of As were detected in tissues of all seabird species collected at colonies in Chernaya Guba (Novaya Zemlya), where nuclear tests were carried out in the 1960s. In general, levels of all of the trace elements in the Barents Sea seabirds were similar or lower in comparison with those reported for the same seabird species from the other Arctic areas. Data on metallothionein concentrations in different seabird species need to be collected in order to understand the mechanism of bioaccumulation and possible toxic effects of trace elements in Arctic seabirds. PMID:12699923

Savinov, Vladimir M; Gabrielsen, Geir W; Savinova, Tatiana N

2003-05-01

362

Biomagnification of mercury and selenium in blue shark Prionace glauca from the Pacific Ocean off Mexico.  

PubMed

The aim of this study was to determine the biomagnification of mercury through the principal prey of the blue shark, Prionace glauca, off the western coast of Baja California Sur, Mexico, as well as the relationship between mercury and selenium in blue sharks. High levels of mercury were found in shark muscle tissues (1.39?±?1.58 ?g/g wet weight); these values are above the allowed 1.0 ?g/g for human consumption. The mercury to selenium molar ratio was 1:0.2. We found a low correlation between mercury bioaccumulation and shark size. Juveniles have lower concentrations of mercury than adults. Regarding the analyzed prey, the main prey of the blue shark, pelagic red crab, Pleuroncodes planipes, bioaccumulated 0.04?±?0.01 ?g/g Hg wet weight, but the prey with higher bioaccumulation was the bullet fish Auxis spp. (0.20?±?0.02 ?g/g wet weight). In terms of volume, the red crab P. planipes can be the prey that provides high levels of mercury to the blue shark. PMID:21465285

Escobar-Sánchez, Ofelia; Galván-Magaña, Felipe; Rosíles-Martínez, René

2011-12-01

363

Bioaccumulation of Mercury in Sharks  

E-print Network

Bioaccumulation of Mercury in Sharks Part 2 a Using a subset of data collected on RJD shark research trips, you will analyze the mercury levels found in the Florida Sharks we catch. Based on your, and hypothesize why that might be. You will also be able to determine whether eating shark is a risk to human

Miami, University of

364

Mercury in ambient air at the Oak Ridge Y-12 Plant, July 1986-December 1990.  

National Technical Information Service (NTIS)

At the Oak Ridge Y-12 Plant, airborne mercury levels are elevated over background levels as a result of mercury vaporization from mercury-contaminated soils, fugitive exhaust from Building 9201-4 (a former lithium isotope separation facility contaminated ...

R. R. Turner, M. A. Bogle, L. L. Heidel, L. M. McCain

1991-01-01

365

Mercury Thermometer Replacement Alternatives Thermometer Description Non-Mercury Non-Mercury Non-Mercury  

E-print Network

Mercury Thermometer Replacement Alternatives Length Thermometer Description Non-Mercury Non-Mercury Non-Mercury Range / Division VWR-Enviro-Safe® Fisherbrand® Brooklyn Thermometer Company Inc. Total/A #12;Mercury Thermometer Replacement Alternatives Length Thermometer Description Non-Mercury Non-Mercury

366

Accumulation levels and characteristics of some pesticides in human adipose tissue samples from Southeast China.  

PubMed

This paper presents a comprehensive study of pesticide levels and bio-accumulation characteristics in human adipose tissues among residents of Southeast China. A large number of adipose samples (n=633) were selected for 58 pesticides and were analyzed by high sensitive Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS). The results showed that POPs pesticides were frequently detected, including 2,4'-DDD, 2,4'-DDE, 2,4'-DDT, 4,4'-DDD, 4,4'-DDE, 4,4'-DDT, ?-HCH, ?-HCH, ?-HCH, ?-HCH, hexachlorobenzene (HCB), and mirex. Other detected pesticide species were dicofol, methamidophos and chlordimeform, which have rarely been reported. Comparing to different countries, the concentrations of total DDT and HCH in these three Chinese southeastern sites were in the middle range, whereas the HCB and mirex were in the lower end. A significant correlation was observed between region as well as age and POPs pesticide levels. Some pesticide residue levels were also found significantly correlated to occupation. However, there was no significant correlation between gender and pesticides. Meanwhile, it is interesting to find that mortality of malignant tumors tends to associate with the pesticides levels in human adipose tissue. More importantly, the measured data presented in this study provide realistic information which is useful for assessing human exposure to pesticides in the general population of Southeast China. PMID:21722941

Wang, Na; Shi, Lili; Kong, Deyang; Cai, Daoji; Cao, Yanzhong; Liu, Yongming; Pang, Guofang; Yu, Rongbin

2011-08-01

367

Modelling the effect of gap junctions on tissue-level cardiac electrophysiology.  

PubMed

When modelling tissue-level cardiac electrophysiology, a continuum approximation to the discrete cell-level equations, known as the bidomain equations, is often used to maintain computational tractability. Analysing the derivation of the bidomain equations allows us to investigate how microstructure, in particular gap junctions that electrically connect cells, affect tissue-level conductivity properties. Using a one-dimensional cable model, we derive a modified form of the bidomain equations that take gap junctions into account, and compare results of simulations using both the discrete and continuum models, finding that the underlying conduction velocity of the action potential ceases to match up between models when gap junctions are introduced at physiologically realistic coupling levels. We show that this effect is magnified by: (i) modelling gap junctions with reduced conductivity; (ii) increasing the conductance of the fast sodium channel; and (iii) an increase in myocyte length. From this, we conclude that the conduction velocity arising from the bidomain equations may not be an accurate representation of the underlying discrete system. In particular, the bidomain equations are less likely to be valid when modelling certain diseased states whose symptoms include a reduction in gap junction coupling or an increase in myocyte length. PMID:24338526

Bruce, Doug; Pathmanathan, Pras; Whiteley, Jonathan P

2014-02-01

368

A Ketogenic Diet Increases Brown Adipose Tissue Mitochondrial Proteins and UCP1 Levels in Mice  

PubMed Central

We evaluated the effects of feeding a ketogenic diet (KD) for a month on general physiology with emphasis on brown adipose tissue (BAT) in mice. KD did not reduce the caloric intake, or weight or lipid content of BAT. Relative epididymal fat pads were 40% greater in the mice fed the KD (P = 0.06) while leptin was lower (P < 0.05). Blood glucose levels were 30% lower while D-?-hydroxybutyrate levels were about 3.5-fold higher in the KD group. Plasma insulin and leptin levels in the KD group were about half of that of the mice fed NIH-31 pellets (chow group). Median mitochondrial size in the inter-scapular BAT (IBAT) of the KD group was about 60% greater, whereas the median lipid droplet size was about half of that in the chow group. Mitochondrial oxidative phosphorylation proteins were increased (1.5–3-fold) and the uncoupling protein 1 levels were increased by threefold in mice fed the KD. The levels of PPAR?, PGC-1?, and Sirt1 in KD group were 1.5–3-fold while level of Sirt3 was about half of that in the chow-fed group. IBAT cyclic AMP levels were 60% higher in the KD group and cAMP response element binding protein was 2.5-fold higher, suggesting increased sympathetic system activity. These results demonstrate that a KD can also increase BAT mitochondrial size and protein levels. PMID:23233333

Srivastava, Shireesh; Baxa, Ulrich; Niu, Gang; Chen, Xiaoyuan; Veech, Richard L.

2013-01-01

369

Resolvin E1 Regulates Inflammation at the Cellular and Tissue Level and Restores Tissue Homeostasis In Vivo1  

Microsoft Academic Search

Resolvin E1 (RvE1) is a potent proresolving mediator of inflammation derived from omega-3 eicosapentaenoic acid that acts locally to stop leukocyte recruitment and promote resolution. RvE1 displays potent counter-regulatory and tissue-protective actions in vitro and in vivo. Periodontal disease is a local inflammatory disease initiated by bacteria characterized by neutrophil- mediated tissue injury followed by development of a chronic immune

Hatice Hasturk; Alpdogan Kantarci; Emilie Goguet-Surmenian; Amanda Blackwood; Chris Andry; Charles N. Serhan; Thomas E. Van Dyke

370

[Levels and distribution of 15 rare earth elements in tumor and normal lung tissue from the patients with lung cancer].  

PubMed

Ten tumor tissue and normal tissue around tumors were collected from the patients with lung cancer. After digested by mixed acids(HNO3:HClO4 = 10:1), 15 rare-earth elements (REEs) in the tissue were measured directly by ELAN 5000 ICP-MS. Tissue levels and distribution of 15 REEs were analyzed and compared with those in healthy human lung tissue measured in the same condition. Re (rhenium) was used as an internal standard element to compensate for matrit inhibition and sensitivity drift. Recoveries of standard addition for REEs was 92.9%-111.3% and the precision was 0.96%-3.07%. Results showed that levels of 15 REEs in normal tissues around the tumor was as 2.07-2.51 times high as those in the tumor tissue, while the REE distribution curves of them was similar. There were positive abnormalities of Ce and negative abnormalities of Eu in REE curves of both tissue after chondrite-normalized. Compared REE level and distribution pattern in normal tissue with those in tumor tissue from patients with lung cancer, it was found that contents of light REE in lung tissue of health human were much higher while the contents of media and heavy REE were much lower. LREE/HREE in the tumor tissue and normal tissue with lung cancer and health human lung tissue were 12.99, 13.72 and 44.11 respectively. This study suggested that there might be light REEs accumulation in human lung tissue compared with REE distribution in the air particulates and soil. Light REEs accumulation in the lung of healthy people was more obviously than that in patients with lung cancer. PMID:14650179

Zhang, Jinliang; Chen, Qing; Wang, Naifen; Zhang, Jing

2003-09-01

371

Mercury, pets' and hair: baseline survey of a priority environmental pollutant using a noninvasive matrix in man's best friend.  

PubMed

Pet cats and dogs have been successfully used as indicators of environmental pollution by a great variety of chemicals, including metals. However, information on mercury (a well know priority environmental pollutant) concentrations in household pets tissues and/or organs is scarce. Thus, in the present work we quantified total mercury (Hg(Total)) in blood and hair samples from twenty-six household dogs. The obtained results disclose relatively low levels of total mercury in the surveyed dogs, with values ranging from 0.16 to 12.38 ng g(-1) in blood; and from 24.16 to 826.30 ng g(-1) in hair. Mercury concentrations were independent of gender, age and diet type. A highly significant positive correlation was established between total mercury in blood and hair, validating the latter as a surrogate, non-invasive matrix for mercury exposure evaluation. Additionally, the obtained blood to hair ratio (200) is similar to the one described for humans reinforcing the suitability of dogs as sentinels. Overall, the determination of total mercury levels in dogs' hair samples proved to be a good screening method for the estimation of mercury burden in this species. We propose the quantification of Hg(Total) in hair as a screening method for sentinels like household pets to be performed in routine veterinary visits. PMID:24085603

Sousa, Ana C A; Teixeira, Isa Sofia de Sá; Marques, Bruna; Vilhena, Hugo; Vieira, Lisete; Soares, Amadeu M V M; Nogueira, António J A; Lillebø, Ana I

2013-11-01

372

Blood glucose partition and levels of glycolytic enzymes in erythrocytes and somatic tissues of penguins.  

PubMed

1. A comparative study was carried out on blood glucose partition and glucose metabolism of penguin erythrocytes and somatic tissues. Pygoscelidae penguins (Pygoscelis antarctica and P. papua) were used in these experiments. 2. Blood glucose partition was established by assaying whole blood and plasma glucose in several individuals of the gentoo and chinstrap penguins. 3. It was found that almost all the whole blood sugar is compartmentalized at the plasma site, the red blood cells being ineffective in regard to glucose metabolism. 4. Levels of hexokinase, phosphoglucose isomerase, phosphofructokinase, fructose bisphosphate aldolase, glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, phosphopyruvate hydratase (enolase), pyruvate kinase, alpha-glycerolphosphate dehydrogenase and fructose bisphosphate phosphatase were estimated in the erythrocytes of both gentoo and chinstrap penguins, the same determinations being carried out also on the somatic tissues (leg muscle, breast muscle, heart muscle, liver and brain) of the gentoo. PMID:2924538

Rosa, R; Rodrigues, E; Bacila, M

1989-01-01

373

Cellular burdens and biological effects on tissue level caused by inhaled radon progenies  

E-print Network

In the case of radon exposure, the spatial distribution of deposited radioactive particles is highly inhomogeneous in the central airways. The objective of this research is to investigate the consequences of this heterogeneity regarding cellular burdens in the bronchial epithelium and to study the possible biological effects on tissue level. Applying a computational fluid dynamics program, the deposition distribution of inhaled radon daughters has been determined in a bronchial airway model for 23 minutes of work in the New Mexico uranium mine corresponding to 0.0129 WLM exposure. A numerical epithelium model based on experimental data has been utilized in order to quantify cellular hits and doses. Finally, a carcinogenesis model considering cell death induced cell cycle shortening has been applied to assess the biological responses. Computations present, that cellular dose may reach 1.5 Gy, which is several orders of magnitude higher than tissue dose. The results are in agreement with the histological findin...

Madas, Balázs G; Farkas, Árpád; Sz?ke, István

2014-01-01

374

Controlled Systemic Delivery by Polymeric Implants Enhances Tissue and Plasma Curcumin Levels Compared with Oral Administration  

PubMed Central

Curcumin possess potent anti-inflammatory and anti-proliferative activities but with poor biopharmaceutical attributes. To overcome these limitations, curcumin implants were developed and tissue (plasma, brain and liver) curcumin concentrations were measured in female ACI rats for 3 months. Biological efficacy of tissue levels achieved was analyzed by modulation of hepatic cytochromes. Curcumin implants exhibited diffusion-mediated biphasic release pattern with ~2-fold higher in vivo release as compared to in vitro. Plasma curcumin concentration from implants was ~3.3 ng/ml on day 1 which dropped to ~0.2 ng/ml after 3 months whereas only 0.2–0.3 ng/ml concentration was observed from 4–12 days with diet and was undetected subsequently. Almost 10 fold higher curcumin levels were observed in brain on day 1 from implants compared with diet (30.1±7.3 vs 2.7±0.8 ng/g) and were higher even after 90 days (7.7±3.8 vs 2.2±0.8 ng/g). Although, curcumin levels were similar in liver from both the routes (~25–30 ng/g from day 1–4 and ~10–15 ng/g at 90 days), implants were more efficacious in altering hepatic CYP1A1 levels and CYP3A4 activity at ~28 fold lower doses. Curcumin implants provided much higher plasma and tissue concentrations and are a viable alternative for delivery of curcumin to various organs like brain. PMID:22227368

Bansal, Shyam S.; Kausar, Hina; Vadhanam, Manicka V.; Ravoori, Srivani; Gupta, Ramesh C.

2012-01-01

375

Elevated Circulating Levels and Tissue Expression of Pentraxin 3 in Uremia: A Reflection of Endothelial Dysfunction  

PubMed Central

Elevated systemic pentraxin 3 (PTX3) levels appear to be a powerful marker of inflammatory status and a superior outcome predictor in patients with chronic kidney disease (CKD). As previous data imply that PTX3 is involved in vascular pathology and that adipose tissue mass may influence circulating PTX3 levels, we aimed to study the importance of adipose tissue expression of PTX3 in the uremic milieu and its relation to endothelial dysfunction parameters. Plasma PTX3 and abdominal subcutaneous adipose tissue (SAT) PTX3 mRNA levels were quantified in 56 stage 5 CKD patients (median age 57 [range 25–75] years, 30 males) and 40 age and gender matched controls (median age 58 [range 20–79] years, 27 males). Associations between PTX3 measures and an extensive panel of clinical parameters, including surrogate markers of endothelial function, were assessed. Functional ex vivo studies on endothelial status and immunohistochemical staining for PTX3 were conducted in resistance subcutaneous arteries isolated from SAT. SAT PTX3 mRNA expression correlated with plasma PTX3 concentrations (rho?=?0.54, p?=?0.0001) and was increased (3.7 [0.4–70.3] vs. 1.2 [0.2–49.3] RQ, p?=?0.02) in CKD patients with cardiovascular disease (CVD), but was not significantly different between patients and controls. The association to CVD was lost after adjustments. SAT PTX3 mRNA levels were independently correlated to asymmetric dimethylarginine and basal resistance artery tone developed after inhibition with nitric oxide synthase and cyclooxygenase (rho?=??0.58, p?=?0.002). Apparent positive PTX3 immunoreactivity was observed in both patient and control arteries. In conclusion, fat PTX3 mRNA levels are associated with measures of endothelial cell function in patients with CKD. PTX3 may be involved in adipose tissue-orchestrated mechanisms that are restricted to the uremic milieu and modify inflammation and vascular complications in CKD patients. PMID:23658833

Witasp, Anna; Rydén, Mikael; Carrero, Juan Jesús; Qureshi, Abdul Rashid; Nordfors, Louise; Näslund, Erik; Hammarqvist, Folke; Arefin, Samsul; Kublickiene, Karolina; Stenvinkel, Peter

2013-01-01

376

Effect of 3-methylcholanthrene-induced increases in ascorbic acid levels on tissue. beta. -glucuronidase activity in rats  

SciTech Connect

The interrelationship between tissue ascorbic acid levels and tissue ..beta..-glucuronidase activity was examined in rats injected with 3-methylcholanthrene, an agent which induces ascorbic acid synthesis in rats. Six Fisher 344 rats were dosed intraperitoneally (IP) with 30 mg/kg of 3-methylcholanthrene. Ascorbic acid levels and ..beta..-glucuronidase (..beta..-G) activity were determined for lung, liver and kidney tissues. In a follow-up study, rats were dosed for three consecutive days with 3-methylcholanthrene. Controls in both groups were dosed IP with Emulphor (EL-620). Animals were sacrificed one week after the final dosage and lung, liver and kidney tissues were examined.

Calabrese, E.J.; Barrett, T.J.; Leonard, D.A.; Horton, H.M.; Kenyon, E.M.

1988-01-01

377

Levels of mercury in muscle and liver of star-spotted dogfish (Mustelus manazo) from the northern region of Japan: a comparison with spiny dogfish (Squalus acanthias).  

PubMed

We analyzed mercury (Hg) concentrations in muscle and liver samples of star-spotted dogfish (Mustelus manazo) caught off the northern region of Japan and compared them with those of spiny dogfish (Squalus acanthias) caught in the same region. The average body length of male star-spotted dogfish specimens was significantly smaller than that of female specimens, reflecting the slower growth rate of male fish. Hg concentrations in liver and muscle increased with increases in body length and estimated age of both male and female star-spotted dogfish specimens. However, the relationships between Hg concentration in liver or muscle and body length or estimated age of male specimens differed markedly from those of female specimens, reflecting differences in growth rate and cessation of growth on reaching maturity. Marked increases in Hg concentration in liver of male and female star-spotted dogfish specimens were observed slightly later than increases in Hg concentration in muscle of those specimens due to growth cessation. These marked increases in Hg in liver may reflect increases in Hg due to the formation of mercury selenide. Similar results were previously reported in spiny dogfish specimens, except spiny dogfish showed only trace levels of Hg in liver (Endo et al., Chemosphere 77:1333-1337, 2009). The greater lipid content in liver and the larger liver size in spiny dogfish may explain the much lower levels of Hg observed in liver of spiny dogfish compared with those in the star-spotted dogfish. PMID:23271344

Endo, Tetsuya; Hisamichi, Yohsuke; Kimura, Osamu; Ogasawara, Hideki; Ohta, Chiho; Koga, Nobuyuki; Kato, Yoshihisa; Haraguchi, Koichi

2013-04-01

378

Dependence of blood levels of HSP70 and HSP90 on genotypes of HSP70, GSTT1, and GSTM1 gene polymorphism in individuals chronically exposed to mercury.  

PubMed

The relationship between blood levels of HSP72, HSP72+HSP73, and HSP90 and genotypes of three polymorphisms of the HSP70 family, HSPA1L (2437T/C) and HSPA1B (2074G/C and 1267A/G) as well as GSTT1 and GSTM1 polymorphisms was studied in 82 men chronically exposed to mercury. Of these, 40 men were exposed to mercury for more than 10 years (group 1) and 42 developed chronic mercuric intoxication (group 2). The groups differed significantly by TT (p=0.004) and TC (p=0.007) genotypes of HSPA1L gene locus 2437T/C. Differences in the heat shock protein content associated with HSP70 gene polymorphism were detected only for HSPA1B gene locus 2074G/C and consisted in reduction of HSP90 (p=0.020) and HSP72 (p=0.056) for GG genotype in group 2 in comparison with group 1. Combination of GSTT1(+)/GSTM1(0/0) genotypes was associated with reduction of the protein levels, while variants including GSTT1(0/0) were associated with a significant elevation thereof. PMID:23330093

Chernyak, Yu I; Itskovich, V B; Baduev, B K; Borovskii, G B

2012-11-01

379

FINAL REPORT ON THE AQUATIC MERCURY ASSESSMENT STUDY  

SciTech Connect

In February 2000, the United States Environmental Protection Agency (EPA) Region 4 issued a proposed Total Maximum Daily Load (TMDL) for total mercury in the middle and lower Savannah River. The initial TMDL, which would have imposed a 1 ng/l mercury limit for discharges to the middle/lower Savannah River, was revised to 2.8 ng/l in the final TMDL released in February 2001. The TMDL was intended to protect people from the consumption of contaminated fish, which is the major route of mercury exposure to humans. The most bioaccumulative form of mercury is methylmercury, which is produced in aquatic environments by the action of microorganisms on inorganic mercury. Because of the environmental and economic significance of the mercury discharge limits that would have been imposed by the TMDL, the Savannah River Site (SRS) initiated several studies concerning: (1) mercury in SRS discharges, SRS streams and the Savannah River, (2) mercury bioaccumulation factors for Savannah River fish, (3) the use of clams to monitor the influence of mercury from tributary streams on biota in the Savannah River, and (4) mercury in rainwater falling on the SRS. The results of these studies are presented in detail in this report. The first study documented the occurrence, distribution and variation of total and methylmercury at SRS industrial outfalls, principal SRS streams and the Savannah River where it forms the border with the SRS. All of the analyses were performed using the EPA Method 1630/31 ultra low-level and contaminant-free techniques for measuring total and methylmercury. Total mercury at National Pollutant Discharge Elimination System (NPDES) outfalls ranged from 0.31-604 ng/l with a mean of 8.71 ng/l. Mercury-contaminated groundwater was the source for outfalls with significantly elevated mercury concentrations. Total mercury in SRS streams ranged from 0.95-15.7 ng/l. Mean total mercury levels in the streams varied from 2.39 ng/l in Pen Branch to 5.26 ng/l in Tims Branch. Methylmercury ranged from 0.002 ng/l in Upper Three Runs to 2.60 ng/l in Tims Branch. Total mercury in the Savannah River ranged from 0.62 ng/l to 43.9 ng/l, and methylmercury ranged from 0.036 ng/l to 7.54 ng/l. Both total and methylmercury concentrations were consistently high in the river near the mouth of Steel Creek. Total mercury was positively correlated with methylmercury (r = 0.88). Total mercury bound to particulates ranged from 41% to 57% in the river and from 28% to 90% in the streams. Particulate methylmercury varied from 9% to 37% in the river and from 6% to 79% in the streams. Small temporary pools in the Savannah River swamp area near and around Fourmile Branch had the highest concentrations observed in the Savannah River watershed, reaching 1,890 ng/l for total mercury and 34.0 ng/l for methylmercury. The second study developed a mercury bioaccumulation factor (BAF) for the Savannah River near SRS. A BAF is the ratio of the concentration of mercury in fish flesh to the concentration of mercury in the water. BAFs are important in the TMDL process because target concentrations for mercury in water are computed from BAFs. Mercury BAFs are known to differ substantially among fish species, water bodies, and possibly seasons. Knowledge of such variation is needed to determine a BAF that accurately represents average and extreme conditions in the water body under study. Analysis of fish tissue and aqueous methylmercury samples collected at a number of locations and over several seasons in a 110 km (68 mile) reach of the Savannah River demonstrated that BAFs for each species under study varied by factors of three to eight. Influences on BAF variability were location, habitat and season-related differences in fish mercury levels and seasonal differences in methylmercury levels in the water. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 10{sup 6} for largemouth bass, 1.4 x 10{sup 6} for sunfishes, and 2.5 x 10{sup 6} for white catfish. This study showed that determination of representative BAFs for large rivers requires the collect

Halverson, N

2008-09-30

380

Antioxidant system activation by mercury in Pfaffia glomerata plantlets  

Microsoft Academic Search

Oxidative stress caused by mercury (Hg) was investigated in Pfaffia\\u000a glomerata plantlets grown in nutrient solution using sand as substrate. Thirty-day-old acclimated plants were treated for 9 days with\\u000a four Hg levels (0, 1, 25 and 50 ?M) in the substrate. Parameters such as growth, tissue Hg concentration, toxicity indicators\\u000a (?-aminolevulinic acid dehidratase, ?-ALA-D, activity), oxidative damage markers (TBARS, lipid peroxidation, and

N. S. Calgaroto; G. Y. Castro; D. Cargnelutti; L. B. Pereira; J. F. Gonçalves; L. V. Rossato; F. G. Antes; V. L. Dressler; E. M. M. Flores; M. R. C. Schetinger; F. T. Nicoloso

2010-01-01

381

Comparable Low-Level Mosaicism in Affected and Non Affected Tissue of a Complex CDH Patient  

PubMed Central

In this paper we present the detailed clinical and cytogenetic analysis of a prenatally detected complex Congenital Diaphragmatic Hernia (CDH) patient with a mosaic unbalanced translocation (5;12). High-resolution whole genome SNP array confirmed a low-level mosaicism (20%) in uncultured cells, underlining the value of array technology for identification studies. Subsequently, targeted Fluorescence In-Situ Hybridization in postmortem collected tissues demonstrated a similar low-level mosaicism, independently of the affected status of the tissue. Thus, a higher incidence of the genetic aberration in affected organs as lung and diaphragm cannot explain the severe phenotype of this complex CDH patient. Comparison with other described chromosome 5p and 12p anomalies indicated that half of the features presented in our patient (including the diaphragm defect) could be attributed to both chromosomal areas. In contrast, a few features such as the palpebral downslant, the broad nasal bridge, the micrognathia, microcephaly, abnormal dermatoglyphics and IUGR better fitted the 5p associated syndromes only. This study underlines the fact that low-level mosaicism can be associated with severe birth defects including CDH. The contribution of mosaicism to human diseases and specifically to congenital anomalies and spontaneous abortions becomes more and more accepted, although its phenotypic consequences are poorly described phenomena leading to counseling issues. Therefore, thorough follow–up of mosaic aberrations such as presented here is indicated in order to provide genetic counselors a more evidence based prediction of fetal prognosis in the future. PMID:21203572

Veenma, Danielle; Beurskens, Niels; Douben, Hannie; Eussen, Bert; Noomen, Petra; Govaerts, Lutgarde; Grijseels, Els; Lequin, Maarten; de Krijger, Ronald; Tibboel, Dick; de Klein, Annelies; Van Opstal, Dian

2010-01-01

382

A multispecies-monitoring study about bioaccumulation of mercury in Iranian birds (Khuzestan to Persian Gulf): Effect of taxonomic affiliation and trophic level.  

PubMed

In the present study, the first baseline concentration of mercury (Hg) in different species of Iranian birds was investigated. From April to October 2005, the tail feathers of 100 birds belonging to 27 species (14 families) from different places in southwest Iran (Khuzestan to Persian Gulf) were collected. The Hg levels were evaluated in relation to taxonomic affiliation and trophic level (type of food). The results showed that the Hg levels in the feathers were between 0.07 and 4.71mg/kg dry weight (dw), and there was a significant effect of taxonomic groups in relation to Hg concentration (p<0.001). The highest mercury concentrations were in Laridae and Ciconidae. Alcedinidae had intermediate values, whereas Upupidae, Glareolidae, Scolopacidae, Turdidae, Ardeidae, Anatidae were in subsequent orders; and the lowest concentrations of Hg were in Rallidae, Cuculidae, Pycnonotidae, Corvidae and Columbidae. The results indicated a significant difference between the trophic levels (p<0.001). Fish predators had the highest level of Hg (3.07mg/kg). Invertebrate predators and herbivorous birds had the lowest concentration of Hg (0.84 and 0.64mg/kg, respectively), whereas crab and fish predators and omnivorous birds had moderate values (1.73 and 1.70mg/kg, respectively). In the present study, the concentration of Hg was significantly higher in tail feathers than in primary and secondary (p<0.001). A significant positive correlation among Hg concentration of feather types was observed (r>0.96). The results obtained in this study indicated that among 100 birds tested, 6% of them had Hg concentrations greater than 5mg/kg in feather (adverse level). PMID:19665701

Zolfaghari, Ghasem; Esmaili-Sari, Abbas; Ghasempouri, Seyed Mahmoud; Baydokhti, Raziyeh Rajabi; Hassanzade Kiabi, Bahram

2009-10-01

383

Organic and total mercury in muscle tissue of five aquatic birds with different feeding habits from the SE Gulf of California, Mexico.  

PubMed

We measured organic and total Hg in muscle tissue of five species of aquatic birds from the south-eastern gulf of California region, Mexico. Concentrations of total and organic Hg measured in Pelecanus occidentalis were the highest (2.85 and 2.68 microgg(-1)); lowest values of organic Hg (0.20 microgg(-1)) and total Hg (0.47 microgg(-1)) were detected in Anas discors and Anas clypeata, respectively. Differences of Hg levels were related to feeding habits, being concentrations in birds of piscivorous habits more elevated than corresponding values in non-piscivorous species. PMID:19419748

Ruelas-Inzunza, J; Hernández-Osuna, J; Páez-Osuna, F

2009-07-01

384

Elemental mercury exposure among children of thermometer plant workers  

SciTech Connect

Because evidence of mercury exposure was found among workers of a mercury thermometer-manufacturing plant in March 1984, the Vermont Department of Health studied the workers' children for both exposure to mercury and evidence of mercury toxicity. The median urine mercury level of 23 workers' children was 25 micrograms/L. This was significantly higher than the level (5 micrograms/L) among 39 children randomly selected from nonworkers' households in the same community (P less than .001). Mercury-in-air levels measured in workers' homes were higher than those measured in control homes. A significant correlation was found between the urine mercury levels of the workers' children and the urine mercury levels of their working parents. No child had frank mercury toxicity. No evidence of neurologic toxicity among exposed children was discovered by a pediatric neurologist who examined these and unexposed children without knowledge of their exposure status. This is the first report demonstrating mercury exposure in children of mercury workers. Although toxic effects of mercury were not demonstrated at these levels of exposure, children of mercury workers are at risk for mercury exposure and potential mercury toxicity.

Hudson, P.J.; Vogt, R.L.; Brondum, J.; Witherell, L.; Myers, G.; Paschal, D.C.

1987-06-01

385

Accumulation levels and characteristics of some pesticides in human adipose tissue samples from Southeast China  

Microsoft Academic Search

This paper presents a comprehensive study of pesticide levels and bio-accumulation characteristics in human adipose tissues among residents of Southeast China. A large number of adipose samples (n=633) were selected for 58 pesticides and were analyzed by high sensitive Gas Chromatography–Tandem Mass Spectrometry (GC–MS\\/MS). The results showed that POPs pesticides were frequently detected, including 2,4?-DDD, 2,4?-DDE, 2,4?-DDT, 4,4?-DDD, 4,4?-DDE, 4,4?-DDT,

Na Wang; Lili Shi; Deyang Kong; Daoji Cai; Yanzhong Cao; Yongming Liu; Guofang Pang; Rongbin Yu

2011-01-01

386

Mercury CEM Calibration  

SciTech Connect

Mercury continuous emissions monitoring systems (CEMS) are being implemented in over 800 coal-fired power plant stacks. The power industry desires to conduct at least a full year of monitoring before the formal monitoring and reporting requirement begins on January 1, 2009. It is important for the industry to have available reliable, turnkey equipment from CEM vendors. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The generators are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 requires that calibration be performed with NIST-traceable standards (Federal Register 2007). Traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued an interim traceability protocol for elemental mercury generators (EPA 2007). The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The document is divided into two separate sections. The first deals with the qualification of generators by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the generator models that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma/mass spectrometry performed by NIST in Gaithersburg, MD. The outputs of mercury generators are compared to one another using a nesting procedure which allows direct comparison of one generator with another and eliminates analyzer variability effects. The qualification portion of the EPA interim traceability protocol requires the vendors to define generator performance as affected by variables such as pressure, temperature, line voltage, and shipping. WRI is focusing efforts to determine actual generator performance related to the variables defined in the qualification portion of the interim protocol. The protocol will then be further revised by EPA based on what can actually be achieved with the generators. Another focus of the study is to evaluate approaches for field verification of generator performance. Upcoming work includes evaluation of oxidized mercury calibration generators, for which a separate protocol will be prepared by EPA. In addition, the variability of the spectrometers/analyzers under various environmental conditions needs to be defined and understood better. A main objective of the current work is to provide data on the performance and capabilities of elemental mercury generator/calibration systems for the development of realistic NIST traceability protocols for mercury vapor standards for continuous emission CEM calibration. This work is providing a direct contribution to the enablement of continuous emissions monitoring at coal-fired power plants in conformance with the CAMR. EPA Specification 12 states that mercury CEMs must be calibrated with NIST-traceable standards (Federal Register 2005). The initial draft of an elemental mercury generator traceability protocol was circulated by EPA in May 2007 for comment, and an interim protocol was issued in August 2007 (EPA 2007). Initially it was assumed that the calibration and implementation of mercury CEMs would be relatively simple, and implementation would follow the implementation of the Clean Air Interstate Rule (CAIR) SO{sub 2} and NO{sub x} monitoring, and sulfur emissions cap and trade. However, mercury has proven to be significantly more difficult

John Schabron; Joseph Rovani; Mark Sanderson

2008-02-29

387

Lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of Canada geese of the New Jersey Meadowlands  

Microsoft Academic Search

The New Jersey Meadowlands are located within the heavily urbanized New York\\/New Jersey Harbor Estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the Hackensack River and nearby waterways. These extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. Persistent contaminants

Nellie Tsipoura; Joanna Burger; Michael Newhouse; Christian Jeitner; Michael Gochfeld; David Mizrahi

2011-01-01

388

Chronic adrenocorticotrophic hormone treatment alters tricyclic antidepressant efficacy and prefrontal monoamine tissue levels.  

PubMed

Several animal models are currently utilised in the investigation of major depressive disorder; however, each is validated by its response to antidepressant pharmacotherapy. Few animal models consider the notion of antidepressant treatment resistance. Chronic daily administration of adrenocorticotropic hormone (ACTH) or corticosterone can alter behavioural responses to antidepressants, effectively blocking antidepressant efficacy. Herein, we demonstrate that ACTH-(1-24) (100?g/day; 14 days) blocks the immobility-reducing 'antidepressant' effects of a single dose of imipramine (10mg/kg) in the forced swim test. This finding was accompanied by altered monoamine tissue levels in the prefrontal cortex (PFC) 1h after exposure to the acute stress of the forced swim test. PFC tissue from ACTH pre-treated animals contained significantly higher serotonin, noradrenaline and adrenaline concentrations relative to saline pre-treated controls. Conversely, dopamine levels were significantly decreased. Altered plasma corticosterone responses to ACTH injections were observed over the treatment course. Measures were taken on treatment days 1, 4, 8, 11, 14 and 15. ACTH administration initially enhanced plasma corticosterone levels, however, these normalised to levels consistent with control animals by day 14. No differences in corticosterone levels were observed across the treatment time course in saline-treated animals. Taken together these results indicate that pre-treatment with ACTH (100?g/day; 14 days) blocks the antidepressant effects of imipramine (10mg/kg), significantly alters key PFC monoamine responses to stress and downregulates glucocorticoid responses. These results suggest that chronic ACTH treatment is a promising paradigm for elucidation of mechanisms mediating antidepressant treatment resistance. PMID:23276607

Walker, Adam J; Burnett, Sandy A; Hasebe, Kyoko; McGillivray, Jane A; Gray, Laura J; McGee, Sean L; Walder, Ken; Berk, Michael; Tye, Susannah J

2013-04-01

389

Phytoremediation of Ionic and Methyl Mercury Pollution  

SciTech Connect

Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of human and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate,