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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 and selenium levels, and selenium:mercury molar ratios of brain, muscle and other tissues in bluefish (Pomatomus saltatrix) from New Jersey, USA  

PubMed Central

A number of contaminants affect fish health, including mercury and selenium, and the selenium: mercury molar ratio. Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for consumption of saltwater fish. Yet the relative ameliorating effects of selenium on toxicity within fish have not been examined, nor has the molar ratio in different tissues, (i.e. brain). We examined mercury and selenium levels in brain, kidney, liver, red and white muscle, and skin and scales in bluefish (Pomatomus saltatrix) from New Jersey to determine whether there were toxic levels of either metal, and we computed the selenium: mercury molar ratios by tissues. Total mercury averaged 0.32 ± 0.02 ppm wet weight in edible muscle and 0.09 ± 0.01 ppm in brain. Selenium concentration averaged 0.37 ± 0.03 in muscle and 0.36 ± 0.03 ppm in brain. There were significant differences in levels of mercury, selenium, and selenium: mercury molar ratios, among tissues. Mercury and selenium levels were correlated in kidney and skin/scales. Mercury levels were highest in kidney, intermediate in muscle and liver, and lowest in brain and skin/scales; selenium levels were also highest in kidney, intermediate in liver, and were an order of magnitude lower in the white muscle and brain. Mercury levels in muscle, kidney and skin/scales were positively correlated with fish size (length). Selenium levels in muscle, kidney and liver were positively correlated with fish length, but in brain; selenium levels were negatively correlated with fish length. The selenium: mercury molar ratio was negatively correlated with fish length for white muscle, liver, kidney, and brain, particularly for fish over 50 cm in length, suggesting that older fish experience less protective advantages of selenium against mercury toxicity than smaller fish, and that consumers of bluefish similarly receive less advantage from eating larger fish. PMID:23202378

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

2015-01-01

3

Tissue-level biomarkers and biological effect of mercury on sentinel slugs, Arion ater  

Microsoft Academic Search

The present investigation was to determine the extent to which mercury (Hg) provokes measurable effects on the structure of the digestive gland of slugs as well as to relate the extent of these effects to the cell and tissue distribution of Hg. For this purpose, slugs (Arion ater) received various dietary concentrations of Hg (from 0 to 1,000 µg Hg\\/g

I. Marigómez; M. Soto; M. Kortabitarte

1996-01-01

4

Brain and tissue levels of mercury after chronic methylmercury exposure in the monkey  

SciTech Connect

Estimated half-lives of mercury following methylmercury exposure in humans are 52-93 d for whole body and 49-164 d for blood. In its most recent 1980 review, the World Health Organization concluded that there was no evidence to suggest that brain half-life differed from whole-body half-life. In the present study, female monkeys (Macaca fascicularis) were dosed for at least 1.7 yr with 10, 25, or 50 micrograms/kg.d of mercury as methylmercuric chloride. Dosing was discontinued, and blood half-life was determined to be about 14 d. Approximately 230 d after cessation of dosing, monkeys were sacrificed and organ and regional brain total mercury levels determined. One monkey that died while still being dosed had brain mercury levels three times higher than levels in blood. Theoretical calculations were performed assuming steady-state brain:blood ratios of 3, 5, or 10. Brain mercury levels were at least three orders of magnitude higher than those predicted by assuming the half-life in brain to be the same as that in blood. Estimated half-lives in brain were between 56 (brain:blood ratio of 3) and 38 (brain:blood ratio of 10) d. In addition, there was a dose-dependent difference in half-lives for some brain regions. These data clearly indicate that brain half-life is considerably longer than blood half-life in the monkey under conditions of chronic dosing.

Rice, D.C.

1989-01-01

5

Wild boar tissue levels of cadmium, lead and mercury in seven regions of continental Croatia.  

PubMed

Concentrations of cadmium, mercury and lead were analysed by atomic absorption spectrometry in the kidney and muscle of free-living wild boar (n = 169) from hunting grounds in seven counties of continental Croatia. Mean levels of metals (mg/kg) in muscle and kidney of boars ranged as follows: Cd: 0.005-0.016 and 0.866-4.58, Pb: 0.033-0.15 and 0.036-0.441, Hg: 0.004-0.012 and 0.04-0.152. In all seven regions, concentrations exceeded the permitted values (muscle and kidney mg/kg: cadmium 0.05/1; lead 0.1/0.5; mercury 0.03/0.1) in 13.6% and 71.6% of samples (muscle and kidney, respectively) for cadmium; 13.6% and 8.9% for lead; 19.5% and 2.4% for mercury. There were significant differences among the regions. Vukovar-Srijem and Virovitica-Podravina Counties were highly contaminated with cadmium, Sisak-Moslavina and Virovitica-Podravina Counties with lead and Brod-Posavina County had highest mercury concentrations. These results suggest a detailed investigation of physiological and environmental factors contributing to accumulation of metals in boars. PMID:20405101

Bilandzi?, Nina; Sedak, Marija; Doki?, Maja; Simi?, Branimir

2010-06-01

6

Tissue-level biomarkers and biological effect of mercury on sentinel slugs, Arion ater.  

PubMed

The present investigation was to determine the extent to which mercury (Hg) provokes measurable effects on the structure of the digestive gland of slugs as well as to relate the extent of these effects to the cell and tissue distribution of Hg. For this purpose, slugs (Arion ater) received various dietary concentrations of Hg (from 0 to 1,000 microg Hg/g food) as chloride for 30 days and were histologically examined every third day. Autometallography was used to demonstrate Hg as black silver deposits (BSD) in paraffin sections. The lysosomes and residual bodies of digestive cells resulted to be the major accumulation sites. In addition, Hg was also evidenced in lipofuscine granules of vacuoles in excretory cells but, however, it was rarely observed within calcium cells. Generally, the extent of BSD increased with dietary Hg concentration and exposure time but, however, it became significant lowered after exposure to 1,000 microg Hg/g food for 30 when the digestive epithelium appeared almost devoid of digestive cells. On the other hand, significant changes were recorded in the quantitative structure of digestive tubules. Mean Epithelial Thickness (MET), Mean Luminal Radius (MLR) and Mean Diverticular Radius (MDR) were recorded as measures of the sublethal biological effect of Hg. MET, MLR/MET and MET/MDR were affected by Hg concentration (C), exposure time (T) and CxT interaction, changes in MET, MLR, MLR/MET and MET/MDR being explained by regression models after logarithmic transformation of the data. In order to explain the nature of the changes in the quantitative structure of the digestive tubules this investigation was complemented with qualitative histological observations. According to them, the excretory activity in digestive cells was initially enhanced. Afterwards, the relative numbers of digestive cells declined until the extreme cases of exposure to 1, 000 microg Hg/g for 27 to 30 days in which the digestive epithelium was mostly comprised of calcium and excretory cells. Concomitantly, some changes took place in blood vessels where Leydig cells became disrupted and the connective tissue layers thickened. Finally, it is suggested to use slugs in soil quality assessment as sentinel organisms ("Slug Watch") in which biomarkers of exposure to metallic pollutants and of biological effect are recorded. PMID:8687990

Marigómez, I; Soto, M; Kortabitarte, M

1996-07-01

7

Development of a method for the determination of ultra-trace level mercury in adipose tissue by cold vapour atomic fluorescence spectrometry  

PubMed Central

A method for the determination of total mercury in rat adipose tissue by cold vapour atomic fluorescence spectrometry (CVAFS) has been developed. Adipose samples were initially subjected to a lyophilization procedure in order to facilitate the homogenization and accurate weighing of small tissue aliquots (~50 mg). A closed vessel microwave digestion procedure using a mixture of sulphuric and nitric acids was used to liberate mercury from the adipose matrix. All mercury species were quantitatively oxidized to Hg(II) by a potassium bromate/bromide oxidation, then reduced to Hg(0) vapour by stannous chloride prior to fluorescence detection. The CVAFS exhibited a linear range of 10 pg Hg/ml to 120 pg Hg/ml. The method detection limit in solution was 2 pg Hg/ml, or 1 ng Hg/g adipose tissue, based on a nominal 50 mg sample and a final volume of 25 ml. A reference material from the National Research Council of Canada (DOLT-2, trace metals in dogfish liver) was prepared in quadruplicate in order to assess the accuracy and precision of the method. Mercury in this material was recovered at 2.22 ± 0.08 ? g/g, which is 104% of the certified level (2.14 ± 0.10 ? g/g). PMID:18924864

Levine, Keith E.; Fernando, Reshan A.; Lang, M.; Essader, Amal; Handy, Robert W.; Collins, Bradley J.

2000-01-01

8

Mercury levels in selected tissues of three kingfisher species; Ceryle rudis, Alcedo atthis , and Halcyon smyrnensi, from Shadegan Marshes of Iran  

Microsoft Academic Search

This study presents concentrations of mercury in tissues (feather, kidney, liver, and muscle) of three kingfisher species\\u000a from Shadegan Marshes located in the Khuzestan province in the lowlands of southwestern Iran at the head of the Persian Gulf.\\u000a The order of mercury concentrations in tissues of all the kingfishers such as pied kingfisher (Ceryle rudis), common kingfisher (Alcedo atthis) and

Rasool Zamani-Ahmadmahmoodi; Abbas Esmaili-Sari; Seyed Mahmoud Ghasempouri; Mozhgan Savabieasfahani

2009-01-01

9

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

E-print Network

1 Accumulation of mercury in the tissues of the common octopus Octopus vulgaris (L.) in two 340 (2005) 113- 122" DOI : 10.1016/j.scitotenv.2004.08.012 #12;2 Abstract: Mercury concentrations were mercury concentrations in different tissues were examined as were correlations between mercury levels

Paris-Sud XI, Université de

10

Interpreting hair mercury levels in individual patients.  

PubMed

Evaluation of mercury exposure in an individual patient ideally includes the presenting history, physical examination, consideration of the differential diagnosis, and mercury analysis of blood and urine specimens. Analysis of mercury in hair specimens may supply useful supplemental information about exposure to organic compounds such as methylmercury, particularly to help reconstruct the pattern of prior exposure. The most appropriate specimen is generally terminal-type hair from the occipital-neck junction, clamped to maintain strand alignment, and oriented to the scalp. Hair from the initial 0.5 cm adjacent to the scalp represents on average 1-3 wk before collection, and consideration of the time frame represented by the specimen is an important part of the evaluation. Literature reports describe hair mercury levels as high as 2400 microg/g. Hair mercury level is usually <1 microg/g in individuals who do not eat fish but may be >30 microg/g in those who frequently consume fish with high mercury content. Hair mercury level is often not correlated with blood mercury concentration or symptoms of mercury toxicity, and reports of hair contamination by exogenous mercury are not uncommon. Hair mercury level is notoriously prone to misinterpretation and should be used with an understanding of its limitations. PMID:16951265

Nuttall, Kern L

2006-01-01

11

Temporal and spatial trends in freshwater fish tissue mercury concentrations associated with mercury emissions reductions.  

PubMed

Mercury (Hg) concentrations were monitored from 1999 to 2011 in largemouth bass (LMB) and yellow perch (YP) in 23 lakes in Massachusetts USA during a period of significant local and regional Hg emissions reductions. Average LMB tissue Hg concentration decreases of 44% were seen in 13 of 16 lakes in a regional Hg "hotspot" area. YP in all lakes sampled in this area decreased 43% after the major emissions reductions. Comparative decreases throughout the remainder of the state were 13% and 19% for LMB and YP respectively. Annual tissue mercury concentration rate decreases were 0.029 (LMB) and 0.016 mg Hg/kg/yr (YP) in the hotspot. In lakes around the rest of the state, LMB showed no trend and YP Hg decreased 0.0068 mg Hg/kg/yr. Mercury emissions from major point sources in the hotspot area decreased 98%, and 93% in the rest of the state from the early 1990s to 2008. The significant declines in fish Hg concentrations in many lakes occurred over the second half of a two decade decrease in Hg emissions primarily from municipal solid waste combustors and, secondarily, from other combustion point sources. In addition to the substantial Hg emissions reductions achieved in Massachusetts, further regional, national and global emissions reductions are needed for fish Hg levels to decrease below fish consumption advisory levels. PMID:24494622

Hutcheson, Michael S; Smith, C Mark; Rose, Jane; Batdorf, Carol; Pancorbo, Oscar; West, Carol Rowan; Strube, Joseph; Francis, Corey

2014-02-18

12

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

13

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

14

Chronic Low-Level mercury exposure and neuropsychological functioning  

Microsoft Academic Search

To measure the effects of chronic low-level exposure to inorganic mercury, the neuropsychological performances of 13 female dental auxiliary workers with elevated head mercury levels (as measured by an X-ray fluorescence technique) were compared with 13 workers with no measurable mercury levels. Workers with elevated mercury levels scored significantly less well on the Recurrent Figures, and SCL-90-R, but not on

Barbara P. Uzzell; Jacqueline Oler

1986-01-01

15

Mercury levels in freshwater fish of the state of South Carolina.  

PubMed

Samples of fish from freshwater sources of rivers, lakes and ponds all over the state of South Carolina were collected during the Summer of 1974 and 1975. The fish collected were Bass, Bluegill, Redbreast, Catfish, Shad, Carp, Crappie, Mudfish and Pike. Samples were analyzed using the flameless atomic absorption procedure outlined by Hatch and Ott, and Uthe et al as modified for use with Perkin-Elmer, Coleman MAS-50 mercury analyzer. Triplicate samples of fish tissue were analyzed by wet digestion method. The mean mercury levels in ppb were determined for baseline mercury levels. A significant finding of this report is that those species for which fish of widely differing weights were analyzed, larger fish had higher mercury levels. Mercury levels exceeding the U.S. Food and Drug Administration guideline of 500 ppb for fish tissues have been found in the Mudfish from Edisto River and Pike fish from Lake Murray. Higher levels of mercury occurred in the highly vascularized blood tissues of liver and kidney than in muscle. Carnivorous and bottom-feeding fishes are the most reliable indicators of mercury pollution. PMID:836979

Koli, A K; Williams, W R; McClary, E B; Wright, E L; Burrell, T M

1977-01-01

16

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

17

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-fired power plants, point sources that release mercury into the atmosphere. Understanding mercury dynamics

18

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

19

Evaluation of Mercury in Urine as an Indicator of Exposure to Low Levels of Mercury Vapor  

Microsoft Academic Search

We conducted a pooled analysis to investigate the relationship between exposure to elemental mercury in air and resulting urinary mercury levels, specifically at lower air levels relevant for envi- ronmental exposures and public health goals (i.e., < 50 µg\\/m3 down to 1.0 µg\\/m3). Ten studies reporting paired air and urine mercury data (149 samples total) met criteria for data quality

Joyce S. Tsuji; Pamela R. D. Williams; Melanie R. Edwards; Krishna P. Allamneni; Michael A. Kelsh; Dennis J. Paustenbach; Patrick J. Sheehan

2002-01-01

20

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

21

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

22

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

23

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.

24

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

25

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...

26

Hair mercury levels in Amazonian populations: spatial distribution and trends  

PubMed Central

Background Mercury is present in the Amazonian aquatic environments from both natural and anthropogenic sources. As a consequence, many riverside populations are exposed to methylmercury, a highly toxic organic form of mercury, because of their intense fish consumption. Many studies have analysed this exposure from different approaches since the early nineties. This review aims to systematize the information in spatial distribution, comparing hair mercury levels by studied population and Amazonian river basin, looking for exposure trends. Methods The reviewed papers were selected from scientific databases and online libraries. We included studies with a direct measure of hair mercury concentrations in a sample size larger than 10 people, without considering the objectives, approach of the study or mercury speciation. The results are presented in tables and maps by river basin, displaying hair mercury levels and specifying the studied population and health impact, if any. Results The majority of the studies have been carried out in communities from the central Amazonian regions, particularly on the Tapajós River basin. The results seem quite variable; hair mercury means range from 1.1 to 34.2 ?g/g. Most studies did not show any significant difference in hair mercury levels by gender or age. Overall, authors emphasized fish consumption frequency as the main risk factor of exposure. The most studied adverse health effect is by far the neurological performance, especially motricity. However, it is not possible to conclude on the relation between hair mercury levels and health impact in the Amazonian situation because of the relatively small number of studies. Conclusions Hair mercury levels in the Amazonian regions seem to be very heterogenic, depending on several factors. There is no obvious spatial trend and there are many areas that have never been studied. Taking into account the low mercury levels currently handled as acceptable, the majority of the Amazonian populations can be considered exposed to methylmercury contamination. The situation for many of these traditional communities is very complex because of their high dependence on fish nutrients. It remains difficult to conclude on the Public Health implication of mercury exposure in this context. PMID:20025776

2009-01-01

27

Mercury  

NASA Technical Reports Server (NTRS)

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, Faith (editor); Chapman, Clark R. (editor); Matthews, Mildred Shapley (editor)

1988-01-01

28

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

E-print Network

Accumulation of mercury in the tissues of the common octopus Octopus vulgaris (L.) in two August 2004 Abstract Mercury concentrations were measured in tissues of 12 individuals of Octopus, gills, mantle, arms, and gonads). Correlations between mercury concentrations in different tissues were

Pierce, Graham

29

A screening-level mercury deposition model for wetland ecosystems  

SciTech Connect

A highly aggregated, three-compartment, carbon cycling model was constructed for a screening-level simulation of net carbon, phosphorus, and mercury deposition in the Everglades Nutrient Removal Project, a 3,742-acre constructed wetland in South Florida. The model was initialized using ENR or Everglades values for model variables. The model was calibrated to calculate biomass turnover, decomposition, and release rates that reproduced the observed apparent phosphorus settling rate constant and the observed organic and inorganic carbon and total phosphorus concentrations in surface sediments. The mercury deposition rate was calculated by partitioning water column mercuric ion onto settling organic and inorganic carbon particles using site-specific or literature values for partition coefficients. From the annual mass balance budget for total mercury calculated with site-specific or literature values, the phosphorus-calibrated model reproduced the observed total mercury concentrations in surface sediments from a typical Everglades marsh within screening-level tolerances.

Fink, L.E. [South Florida Water Management District, West Palm Beach, FL (United States)

1995-12-31

30

Increased blood mercury levels in patients with Alzheimer's disease  

Microsoft Academic Search

Summary.   Alzheimer's disease (AD) is a common neurodegenerative disorder that leads to dementia and death. In addition to several\\u000a genetic parameters, various environmental factors may influence the risk of getting AD. In order to test whether blood levels\\u000a of the heavy metal mercury are increased in AD, we measured blood mercury concentrations in AD patients (n = 33), and compared

C. Hock; G. Drasch; S. Golombowski; F. Müller-Spahn; B. Willershausen-Zönnchen; P. Schwarz; U. Hock; J. H. Growdon; R. M. Nitsch

1998-01-01

31

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

32

Distribution of mercury in the tissues of five species of freshwater fish from Lake Mead, USA.  

PubMed

Total mercury (Hg) concentrations were determined in seven tissues (skeletal muscle, liver, blood, gonad, brain, gill, and heart) of 59 striped bass and four tissues (muscle, liver, blood, and gonad) of 69 largemouth bass, 76 channel catfish, 12 bluegill, and 22 blue tilapia collected from Lake Mead, USA. Mercury levels generally increased according to trophic level and fish length. For striped bass, mean Hg levels (ng g(-1), wet mass) were highest in the liver (531), followed by muscle (309), heart (186), gonad (136), brain (77), gill (52), and blood (36). Similarly, Hg levels in the catfish and tilapia were liver > muscle > gonad > blood. In contrast, largemouth bass and bluegill had the highest levels in muscle, followed by liver, gonad, and blood. Generally, Hg levels were strongly correlated among the tissues, especially for blood/muscle and blood/liver. As the body burden of Hg increased, the concentration in blood and organs increased relative to the concentration in muscle. The trend was most pronounced for the liver. These relationships could form the basis of a predictive model and suggest that blood and muscle (plugs) could be useful for a non-lethal measure of Hg concentration and exposure in fish. For the striped bass, elevated Hg levels in the tissues were also correlated with degree of emaciation. Liver-to-muscle ratios were similar to literature values, except for tilapia with an average ratio of approximately 1.7, which is higher than generally reported for non-piscivores. Finally, this study demonstrates the usefulness of a solid sampling approach in trace element monitoring, especially as pertaining to in vivo analysis, analysis of a large number of samples and reduction of contamination risk. PMID:14587853

Cizdziel, J; Hinners, T; Cross, C; Pollard, J

2003-10-01

33

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

34

Mercury levels in sediments and mangrove oysters, Crassostrea rizophorae, from the north coast of Villa Clara, Cuba.  

PubMed

Total mercury levels were quantified in sediments and oyster tissues (Crassostrea rizophorae) from the Sagua la Grande River estuary and offshore mangrove keys 19 km downstream of a chlor-alkali plant (CAP) in Villa Clara, Cuba. Relatively elevated total mercury levels were found in sediments from the estuary itself, ranging from 0.507 to 1.81 ?g g(-1) dry weight. However, levels were lower in sediments from the keys farther from the estuary. Oyster mercury levels were always acceptable for human consumption, although levels significantly correlated in sediments and oysters across sampling sites (p < 0.05), which suggests that mercury from the CAP is impacting coastal water quality conditions. PMID:22323046

Olivares-Rieumont, S; Lima, L; Rivero, S; Graham, D W; Alonso-Hernandez, C; Bolaño, Y

2012-04-01

35

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

36

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...

37

Are liver and renal lesions in East Greenland polar bears (Ursus maritimus) associated with high mercury levels?  

PubMed Central

Background In the Arctic, polar bears (Ursus maritimus) bio-accumulate mercury as they prey on polluted ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). Studies have shown that polar bears from East Greenland are among the most mercury polluted species in the Arctic. It is unknown whether these levels are toxic to liver and kidney tissue. Methods We investigated the histopathological impact from anthropogenic long-range transported mercury on East Greenland polar bear liver (n = 59) and kidney (n = 57) tissues. Results Liver mercury levels ranged from 1.1–35.6 ?g/g wet weight and renal levels ranged from 1–50 ?g/g wet weight, of which 2 liver values and 9 kidney values were above known toxic threshold level of 30 ?g/g wet weight in terrestrial mammals. Evaluated from age-correcting ANCOVA analyses, liver mercury levels were significantly higher in individuals with visible Ito cells (p < 0.02) and a similar trend was found for lipid granulomas (p = 0.07). Liver mercury levels were significantly lower in individuals with portal bile duct proliferation/fibrosis (p = 0.007) and a similar trend was found for proximal convoluted tubular hyalinisation in renal tissue (p = 0.07). Conclusion Based on these relationships and the nature of the chronic inflammation we conclude that the lesions were likely a result of recurrent infections and ageing but that long-term exposure to mercury could not be excluded as a co-factor. The information is important as it is likely that tropospheric mercury depletion events will continue to increase the concentrations of this toxic heavy metal in the Sub Arctic and Arctic marine food webs. PMID:17439647

Sonne, Christian; Dietz, Rune; Leifsson, Pall S; Asmund, Gert; Born, Erik W; Kirkegaard, Maja

2007-01-01

38

Maternal Fish Consumption, Mercury Levels, and Risk of Preterm Delivery  

PubMed Central

Background Pregnant women receive mixed messages about fish consumption in pregnancy because unsaturated fatty acids and protein in fish are thought to be beneficial, but contaminants such as methylmercury may pose a hazard. Methods In the Pregnancy Outcomes and Community Health (POUCH) study, women were enrolled in the 15th to 27th week of pregnancy from 52 prenatal clinics in five Michigan communities. At enrollment, information was gathered on amount and category of fish consumed during the current pregnancy, and a hair sample was obtained. A segment of hair closest to the scalp, approximating exposure during pregnancy, was assessed for total mercury levels (70–90% methylmercury) in 1,024 POUCH cohort women. Results Mercury levels ranged from 0.01 to 2.50 ?g/g (mean = 0.29 ?g/g; median = 0.23 ?g/g). Total fish consumption and consumption of canned fish, bought fish, and sport-caught fish were positively associated with mercury levels in hair. The greatest fish source for mercury exposure appeared to be canned fish. Compared with women delivering at term, women who delivered before 35 weeks’ gestation were more likely to have hair mercury levels at or above the 90th percentile (? 0.55 ?g/g), even after adjusting for maternal characteristics and fish consumption (adjusted odds ratio = 3.0; 95% confidence interval, 1.3–6.7). Conclusion This is the first large, community-based study to examine risk of very preterm birth in relation to mercury levels among women with low to moderate exposure. Additional studies are needed to see whether these findings will be replicated in other settings. PMID:17366817

Xue, Fei; Holzman, Claudia; Rahbar, Mohammad Hossein; Trosko, Kay; Fischer, Lawrence

2007-01-01

39

Mercury levels of marine fish commonly consumed in Peninsular Malaysia.  

PubMed

This study was conducted to determine the concentration of total mercury in the edible portion of 46 species of marine fish (n?=?297) collected from selected major fish landing ports and wholesale markets throughout Peninsular Malaysia. Samples were collected in June to December 2009. Prior to analysis, the fish samples were processed which consisted of drying at 65 °C until a constant weight was attained; then, it was grounded and digested by a microwave digestion system. The analytical determination was carried out by using a mercury analysis system. Total mercury concentration among fish species was examined. The results showed that mercury concentrations were found significantly higher (p?mercury concentrations were also higher in carnivorous fish especially in the species with more predatory feeding habits. Besides, the family group of Latidae (0.537?±?0.267 mg/kg in dried weight), Dasyatidae (0.492?±?0.740 mg/kg in dried weight), and Lutjanidae (0.465?±?0.566 mg/kg in dried weight) showed significantly (p?mercury levels compared to other groups. Fish collected from Port Klang (0.563?±?0.509 mg/kg in dry weight), Kuala Besar (0.521?±?0.415 mg/kg in dry weight), and Pandan (0.380?±?0.481 mg/kg in dry weight) were significantly higher (p?=?0.014) in mercury concentrations when compared to fish from other sampling locations. Total mercury levels were significantly higher (p?20 cm) and were positively related with fish size (length and weight) in all fish samples. Despite the results, the level of mercury in marine fish did not exceed the permitted levels of Malaysian and JECFA guideline values at 0.5 mg/kg methylmercury in fish. PMID:25256581

Ahmad, Nurul Izzah; Noh, Mohd Fairulnizal Mohd; Mahiyuddin, Wan Rozita Wan; Jaafar, Hamdan; Ishak, Ismail; Azmi, Wan Nurul Farah Wan; Veloo, Yuvaneswary; Hairi, Mohd Hairulhisam

2014-09-26

40

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...

41

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

42

Method development and sample processing of water, soil, and tissue for the analysis of total and organic mercury by cold vapor atomic fluorescence spectrometry  

Microsoft Academic Search

Atomic Fluorescence-based methods have been developed for measuring ultratrace levels of mercury (Hg) in environmental (water, soil) and biological (fish tissue) samples. In addition, methods for preparation of water, soil, and tissue samples have been developed. For the analysis of total Hg in soil, sediment and fish the samples are digested with concentrated nitric acid in sealed glass ampules, and

R. D. Jones; M. E. Jacobson; R. Jaffe; J. West-Thomas; C. Arfstrom; A. Alli

1995-01-01

43

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

44

Mercury and selenium content and chemical form in human and animal tissue.  

PubMed

The content, chemical form, and distribution of mercury and selenium were determined for selected samples of human and animal tissue by gas chromatography. Methylmercury averaged 38.7% of the total mercury content in homogenized human brain. For human heart, spleen, liver, kidney and placenta, methylmercury comprised 40.2%, 57.0%, 39.6%, 6.0% and 57.1% respectively, of the total mercury content. Similar results were obtained for the heart and liver of a whitetail deer. Methylmercury represented 9.1%, 62.9% and 24.1% of the total mercury content in seal liver, seal meat and deer meat, respectively. For all samples, a significant portion of the total selenium content, averaging 27%, was present as selenate (Se VI). Tissue selenium content did not correlate with the corresponding mercury content. In brain, heart and placenta, and in seal liver and meat, 53% to 80% of the total mercury content was water-extractable. For human kidney, liver and spleen, and deer meat, only 15% to 45% of the total mercury was extractable. On a percentage basis, inorganic mercury was more extractable than methylmercury, except for human kidney and liver, and deer meat. For all samples, except kidney, liver and deer meat, 55% to 76% of the total selenium content was water-extractable, Se VI being more extractable on a percentage basis than selenite (Se IV) and selenide (Se-II). PMID:7242026

Cappon, C J; Smith, J C

1981-01-01

45

Determination of total mercury in nuts at ultratrace level.  

PubMed

Total mercury, at ?g kg(-1) level, was determined in different types of nuts (cashew nut, Brazil nuts, almond, pistachio, peanut, walnut) using a direct mercury analyser after previous sample defatting and by cold vapour atomic fluorescence spectrometry. There is not enough sensitivity in the second approach to determine Hg in previously digested samples due to the strong matrix effect. Mercury levels in 25 edible nut samples from Brazil and Spain were found in the range from 0.6 to 2.7?g kg(-1) by using the pyrolysis of sample after the extraction of the nut fat. The accuracy of the proposed method was confirmed by analysing certified reference materials of Coal Fly Ash-NIST SRM 1633b, Fucus-IAEA 140 and three unpolished Rice Flour NIES-10. The observed results were in good agreement with the certified values. The recoveries of different amounts of mercury added to nut samples ranged from 94 to 101%. RSD values corresponding to three measurements varied between 2.0 and 14% and the limit of detection and quantification of the method were 0.08 and 0.3?g kg(-1), respectively. PMID:25064238

da Silva, Maria José; Paim, Ana Paula S; Pimentel, Maria Fernanda; Cervera, M Luisa; de la Guardia, Miguel

2014-08-01

46

Levels of mercury in alligators (Alligator mississippiensis) collected along a transect through the Florida Everglades  

USGS Publications Warehouse

As part of a multi-agency study of alligator health, 28 American alligators (Alligator mississippiensis) were captured along a transect through the Florida Everglades in 1999. Liver and tail muscle tissues were sampled and analyzed on a wet weight basis for total mercury (THg) using cold-vapor atomic absorption spectrophotometry. All tissues had detectable concentrations of THg that ranged from 0.6 to 17 mg/kg in liver and from 0.1 to 1.8 mg/kg in tail muscle. THg was more concentrated in liver tissue than tail muscle, but levels were highly correlated between tissues. THg concentrations in tissue differed significantly among locations, with animals from Everglades National Park (ENP) having mean concentrations of THg in liver (10.4 mg/kg) and tail muscle (1.2 mg/kg) that were two-fold higher than basin-wide averages (4.9 and 0.64 mg/kg, respectively). The reasons for higher contamination of ENP alligators were unclear and could not be explained by differences in sex, length, weight or animal age. While ??15N values were positively correlated with THg concentrations in tail muscle, spatial patterns in isotopic composition did not explain the elevated THg levels in ENP alligators. Therefore, it appears that ENP alligators were more highly exposed to mercury in their environment than individuals in other areas. Comparisons to a previous survey by Yanochko et al. [Arch Environ Contam Toxicol 32 (1997) 323] suggest that mercury levels have declined in some Everglades alligators since 1994. ?? 2002 Elsevier Science B.V. All rights reserved.

Rumbold, D.G.; Fink, L.E.; Laine, K.A.; Niemczyk, S.L.; Chandrasekhar, T.; Wankel, S.D.; Kendall, C.

2002-01-01

47

DISTRIBUTION OF MERCURY IN THE TISSUES OF FIVE SPECIES OF FRESHWATER FISH FROM LAKE MEAD, USA  

EPA Science Inventory

Total mercury (Hg) concentrations were determined in seven tissues (skeletal muscle, liver, blood, gonad, brain, gill, and heart) of 59 striped bass and four tissues (muscle, liver, blood, and gonad) of 69 largemouth bass, 76 channel catfish, 12 bluegill, and 22 blue tila...

48

Maternal and umbilical cord blood levels of mercury, lead, cadmium, and essential trace elements in Arctic Canada  

Microsoft Academic Search

Maternal and umbilical cord blood levels of mercury (Hg), lead (Pb), cadmium (Cd), and the trace elements copper (Cu), zinc (Zn), and selenium (Se) are reported for Inuit, Dene\\/Metis, Caucasian, and Other nonaboriginal participants from Arctic Canada. This is the first human tissue monitoring program covering the entire Northwest Territories and Nunavut for multiple contaminants and establishes a baseline upon

Shawn G. Donaldsong; Jay Van Oostdamg; J. Butler Walker

49

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

PubMed

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 392Hgppmdw) than the general population sampled. PMID:21867998

Marino, Kady B; Hoover-Miller, Anne; Conlon, Suzanne; Prewitt, Jill; O'Shea, Stephen K

2011-11-01

50

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

51

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

52

Hair mercury levels versus freshwater fish consumption in household members of Swedish angling societies  

Microsoft Academic Search

Hair mercury levels were determined in 143 individuals from households of members in angling societies in an area of Sweden with many lakes that have freshwater fish with relatively high mercury levels. Thus, the individuals had a potentially high intake of methyl mercury. The mean mercury concentration of pike and perch was approximately 0.7mg\\/g. One-third of the subjects consumed these

Cecilia Johnsson; Gerd Sallsten; Andrejs Schutz; Anna Sjors; Lars Barregarda

53

Unexpectedly high mercury level in pelleted commercial fish feed  

Microsoft Academic Search

An unexpectedly high mercury (Hg) level was found in a pelleted commercial fish feed used to feed fish in laboratory and fish farm settings. Mean total Hg (T-Hg) concentration in the commercial fish pellets was 66 ppb. Mean total selenium (T-Se) concentration in the pellets was 1,120 ppb (ranging from 790 to 1,360 ppb). Total Hg and Se in the

Monica Heekyoung Choi; Joseph J. Cech

1998-01-01

54

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.

55

Mercury  

MedlinePLUS

... several forms. Metallic mercury is a shiny, silver-white, odorless liquid. If heated, it is a colorless, odorless gas. It also combines with other elements to form powders or crystals. Mercury is in many products. Metallic ...

56

Mercury  

MedlinePLUS

... aimed to continue agency efforts to reduce mercury pollution, as part of the international commitments of the ... and processing is a major cause of air pollution from mercury. EPA and Argonne National Laboratory worked ...

57

Glutathione level after long-term occupational elemental mercury exposure.  

PubMed

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 degrees ) 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 degrees -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 degrees 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. PMID:17706633

Kobal, Alfred Bogomir; Prezelj, Marija; Horvat, Milena; Krsnik, Mladen; Gibicar, Darija; Osredkar, Josko

2008-05-01

58

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

59

Evaluating the potential efficacy of mercury total maximum daily loads on aqueous methylmercury levels in four coastal watersheds.  

PubMed

Of the approximately 780 U.S. EPA approved mercury total maximum daily loads (TMDLs), most specify a reduction in total mercury (Hg(T)) loads to reduce methylmercury levels in fish tissue, assuming a 1:1 correspondence. However, mercury methylation is more complex, and therefore, proposed load reductions may not be adequate. Using multiple regression with microlevel and macrolevel variables, the potential efficacy of mercury TMDLs on decreasing aqueous methylmercury levels was investigated in four coastal watersheds: Mugu Lagoon (CA), San Francisco Bay Estuary, Long Island Sound, and south Florida. Hg(T) and methylmercury levels were positively correlated in all watersheds except in Long Island Sound, where spatial differences explained over 40% of the variability in methylmercury levels. A mercury TMDL would be least effective in Long Island Sound due to spatial heterogeneity but most effective in south Florida, where the ratio between aqueous Hg(T) and methylmercury levels was close to 1 and the 95% confidence interval was narrow, indicating a probable reduction in aqueous methylmercury levels if Hg(T) loads were reduced. PMID:18754452

Rothenberg, Sarah E; Ambrose, Richard F; Jay, Jennifer A

2008-08-01

60

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...

61

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

62

Determination of total mercury in biological tissue by isotope dilution ICPMS after UV photochemical vapor generation.  

PubMed

A method is developed for the determination of trace mercury in biological samples using photo chemical vapor generation (PVG) and isotope dilution inductively coupled plasma mass spectrometry (ID ICPMS) detection. Biological tissues were solubilized in formic acid. Subsequently, the sample solutions were exposed to an ultraviolet (UV) source for the reduction of mercury into vapor species prior to ICPMS measurements. The formic acid served not only as a tissue solubilizer in the sample preparation procedure, but also as a photochemical reductant for mercury in the PVG process. The problem arising from the opaque formic acid digested solution was efficiently solved by using ID method. The optimum conditions for sample treatment and PVG were investigated. A limit of detection (LOD) of 0.5 pg g(-1), based on an external calibration, provided 350-fold improvement over that obtained by utilizing conventional pneumatic nebulization sample introduction. Method validation was demonstrated by the determination of total mercury in several biological tissue certified reference materials (CRMs). The results were in good agreement with the certified values. PMID:24209355

Liu, Rui; Xu, Mo; Shi, Zeming; Zhang, Jiayun; Gao, Ying; Yang, Lu

2013-12-15

63

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

64

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 (R² < 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

65

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

66

Lead, cadmium and mercury levels in the 2010 Korean diet.  

PubMed

This study analysed the level of contamination of harmful heavy metals in 3820 food samples available in Korea in 2010. A total of 119 types of samples were collected, including corns, vegetables, fruits, fishes, mollusks, shellfish, crustaceans, seaweed, bean products, meats and eggs from seven major cities. These samples were analysed using ICP-MS after pre-treatment with a microwave-digestion system. Results of lead, cadmium and mercury analyses were compared with the standard specifications of Korea Food Standards Codex. As a result, high levels of Pb, Cd and Hg were detected in "cockle," "dried-squid" and "shark-meat." Acceptable intake for consumers was checked using provisional tolerable weekly intake values. Such results will be utilised as data on the exposure of human body through foods. In addition, satisfactory results were obtained through purchase and analysis of National Institute of Science and Technology-certified reference materials to obtain reliability on analysis results. PMID:24786406

Kim, Jae Hoon; Lee, Ji Yeon; Seo, Joo Ee; Jeong, Ji Yoon; Jung, Ki Kyung; Yoon, Hae Jung; Park, Kyung Su

2012-01-01

67

Mercury burden and health impairment in dental auxilaries. Final report  

Microsoft Academic Search

An effort was made to develop a safe and effective x-ray fluorescence system for monitoring mercury and other elements in human tissues in-situ, to determine mercury levels in 207 dental auxiliaries exposed to dental amalgam on the job, to evaluate mercury in matching nonexposed populations and in 298 dentists using mercury amalgam, and to evaluate deficiencies in central and peripheral

I. M. Shapiro; P. Bloch; I. I. Ship; L. Spitz; A. Summer

1988-01-01

68

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

Microsoft Academic Search

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

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

2012-01-01

69

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

70

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

71

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

72

Mercury and histopathology of the vulnerable goliath grouper, Epinephelus itajara, in U.S. waters: a multi-tissue approach.  

PubMed

Goliath grouper have undergone significant global population declines with potential biological extinction for some subpopulations. Although overfishing and habitat loss are important drivers of these declines, the negative effects of contaminants may also play a role. The life history patterns of goliath grouper may make this species especially prone to exposure to contaminants and may exacerbate bioaccumulation of toxic substances, including mercury, which has documented detrimental health effects. Therefore, we analyzed mercury (in muscle, liver, kidney, gonad, and brain tissue) and the histology of key organs (liver, kidney and gill tissue) in 56 goliath groupers from U.S. waters. Total mercury concentration was greatest in liver tissue, followed by kidney, muscle, gonad, and brain. Maximum mercury concentration ranged from 22.68 ?g/g in liver tissue to 0.89 ?g/g in brain tissue. Mean mercury concentration ranged from 2.87 ?g/g in liver tissue to 0.37 ?g/g in brain tissue with a mean of 0.63 ?g/g in muscle. Mean mercury concentrations observed in goliath grouper from U.S. waters were within the range known to cause direct health effects in fish after long-term exposure. The lesions and histological changes observed in the liver, kidney, and gills of goliath groupers were similar to those found in other fish following laboratory mercury-exposure trials and to those found in mercury-contaminated fish in wild populations carrying similar or even lower concentrations. We suggest that exposure to mercury and other environmental influences such as pathogens and reduced temperatures could be co-factors in the histological effects or anomalies observed in the present study, and resulting stresses may be involved in the observed population declines in the species. PMID:23830062

Adams, Douglas H; Sonne, Christian

2013-10-01

73

Ultralow Level Mercury Treatment Using Chemical Reduction and Air Stripping: Scoping Report  

SciTech Connect

Data collected during the first stage of a Savannah River Technology Center (SRTC) Strategic Research and Development Project confirmed the efficacy of chemical reduction and air stripping/sparging as an ultralow level mercury treatment concept for waters containing Hg(II). The process consists of dosing the water with low levels of stannous chloride to convert the mercury to Hg. This form of mercury can easily be removed from the water by air stripping or sparging. Samples of Savannah River Site (SRS) groundwater containing approximately 130 ng/L of total mercury (as Hg(II)) were used for the study. In undosed samples, sparging removed 0 percent of the initial mercury. In the dosed samples, all of the removals were greater than 94 percent, except in one water type at one dose. This sample, which was saturated with dissolved oxygen, showed a 63 percent reduction in mercury following treatment at the lowest dose. Following dosing at minimally effective levels and sparging, treated water contained less than 10 ng/L total mercury. In general, the data indicate that the reduction of mercury is highly favored and that stannous chloride reagent efficiently targets the Hg(II) contaminant in the presence of competing reactions. Based on the results, the authors estimated that the costs of implementing and operating an ultralow level mercury treatment process based on chemical reduction and stripping/sparging are 10 percent to 20 percent of traditional treatment technologies.

Looney, B.B.

2000-08-18

74

Mercury  

MedlinePLUS

... and fluid loss, kidney failure, and likely death. Chronic brain damage from organic mercury is difficult to ... MJ, eds. Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose . 4th ed. Philadelphia, PA: Saunders ...

75

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

76

Mercury in the pelagic food web of Lake Champlain.  

PubMed

Lake Champlain continues to experience mercury contamination resulting in public advisories to limit human consumption of top trophic level fish such as walleye. Prior research suggested that mercury levels in biota could be modified by differences in ecosystem productivity as well as mercury loadings. We investigated relationships between mercury in different trophic levels in Lake Champlain. We measured inorganic and methyl mercury in water, seston, and two size fractions of zooplankton from 13 sites representing a range of nutrient loading conditions and productivity. Biomass varied significantly across lake segments in all measured ecosystem compartments in response to significant differences in nutrient levels. Local environmental factors such as alkalinity influenced the partitioning of mercury between water and seston. Mercury incorporation into biota was influenced by the biomass and mercury content of different ecosystem strata. Pelagic fish tissue mercury was a function of fish length and the size of the mercury pool associated with large zooplankton. We used these observations to parameterize a model of mercury transfers in the Lake Champlain food web that accounts for ecosystem productivity effects. Simulations using the mercury trophic transfer model suggest that reductions of 25-75% in summertime dissolved eplimnetic total mercury will likely allow fish tissue mercury concentrations to drop to the target level of 0.3 ?g g(-1) in a 40-cm fish in all lake segments. Changes in nutrient loading and ecosystem productivity in eutrophic segments may delay any response to reduced dissolved mercury and may result in increases in fish tissue mercury. PMID:22193540

Miller, Eric K; Chen, Celia; Kamman, Neil; Shanley, James; Chalmers, Ann; Jackson, Brian; Taylor, Vivien; Smeltzer, Eric; Stangel, Pete; Shambaugh, Angela

2012-04-01

77

Mercury in the Pelagic Food Web of Lake Champlain  

PubMed Central

Lake Champlain continues to experience mercury contamination resulting in public advisories to limit human consumption of top trophic level fish such as walleye. Prior research suggested that mercury levels in biota could be modified by differences in ecosystem productivity as well as mercury loadings. We investigated relationships between mercury in different trophic levels in Lake Champlain. We measured inorganic and methyl mercury in water, seston, and two size fractions of zooplankton from 13 sites representing a range of nutrient loading conditions and productivity. Biomass varied significantly across lake segments in all measured ecosystem compartments in response to significant differences in nutrient levels. Local environmental factors such as alkalinity influenced the partitioning of mercury between water and seston. Mercury incorporation into biota was influenced by the biomass and mercury content of different ecosystem strata. Pelagic fish tissue mercury was a function of fish length and the size of the mercury pool associated with large zooplankton. We used these observations to parameterize a model of mercury transfers in the Lake Champlain food web that accounts for ecosystem productivity effects. Simulations using the mercury trophic transfer model suggest that reductions of 25 to 75% in summertime dissolved eplimnetic total mercury will likely allow fish tissue mercury concentrations to drop to the target level of 0.3 µg g?1 in a 40-cm fish in all lake segments. Changes in nutrient loading and ecosystem productivity in eutrophic segments may delay any response to reduced dissolved mercury and may result in increases in fish tissue mercury. PMID:22193540

Chen, Celia; Kamman, Neil; Shanley, James; Chalmers, Ann; Jackson, Brian; Taylor, Vivien; Smeltzer, Eric; Stangel, Pete; Shambaugh, Angela

2013-01-01

78

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

79

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

80

REVIEW OF PUBLISHED LITERATURE FOR MEASUREMENT OF MERCURY AND METHYL MERCURY LEVELS FOR FISH AND FISH-EATING BIRDS IN CARSON RIVER  

EPA Science Inventory

This project involves conducting a literature search with the goal of identifying "robust" methods for measuring mercury concentrations in biological tissues. Mercury is a significant contaminant of concern in Region 9, due in large part to the extensive mining activities of the...

81

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

82

Mercury Reduction and Removal from High Level Waste at the Defense Waste Processing Facility - 12511  

SciTech Connect

The Defense Waste Processing Facility processes legacy nuclear waste generated at the Savannah River Site during production of enriched uranium and plutonium required by the Cold War. The nuclear waste is first treated via a complex sequence of controlled chemical reactions and then vitrified into a borosilicate glass form and poured into stainless steel canisters. Converting the nuclear waste into borosilicate glass is a safe, effective way to reduce the volume of the waste and stabilize the radionuclides. One of the constituents in the nuclear waste is mercury, which is present because it served as a catalyst in the dissolution of uranium-aluminum alloy fuel rods. At high temperatures mercury is corrosive to off-gas equipment, this poses a major challenge to the overall vitrification process in separating mercury from the waste stream prior to feeding the high temperature melter. Mercury is currently removed during the chemical process via formic acid reduction followed by steam stripping, which allows elemental mercury to be evaporated with the water vapor generated during boiling. The vapors are then condensed and sent to a hold tank where mercury coalesces and is recovered in the tank's sump via gravity settling. Next, mercury is transferred from the tank sump to a purification cell where it is washed with water and nitric acid and removed from the facility. Throughout the chemical processing cell, compounds of mercury exist in the sludge, condensate, and off-gas; all of which present unique challenges. Mercury removal from sludge waste being fed to the DWPF melter is required to avoid exhausting it to the environment or any negative impacts to the Melter Off-Gas system. The mercury concentration must be reduced to a level of 0.8 wt% or less before being introduced to the melter. Even though this is being successfully accomplished, the material balances accounting for incoming and collected mercury are not equal. In addition, mercury has not been effectively purified and collected in the Mercury Purification Cell (MPC) since 2008. A significant cleaning campaign aims to bring the MPC back up to facility housekeeping standards. Two significant investigations are being undertaken to restore mercury collection. The SMECT mercury pump has been removed from the tank and will be functionally tested. Also, research is being conducted by the Savannah River National Laboratory to determine the effects of antifoam addition on the behavior of mercury. These path forward items will help us better understand what is occurring in the mercury collection system and ultimately lead to an improved DWPF production rate and mercury recovery rate. (authors)

Behrouzi, Aria [Savannah River Remediation, LLC (United States); Zamecnik, Jack [Savannah River National Laboratory, Aiken, South Carolina, 29808 (United States)

2012-07-01

83

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

84

Investigation of increased mercury levels in the fisheries of Lower East Fork Poplar Creek (Lefpc), Oak Ridge Reservation, Tennessee  

SciTech Connect

The DOE Western Environmental Technology Office (WETO) is supporting remediation efforts on the U.S. Department of Energy Oak Ridge Reservation in Oak Ridge, Tennessee by performing this study. MSE Technology Applications, Inc. (MSE) has performed a series of literature reviews and bench-scale testing to further evaluate the mercury problem in the Lower East Fork Poplar Creek (LEFPC) at Oak Ridge. The primary problem is that total mercury (HgT) levels in LEFPC water decrease, while HgT levels in sunfish muscle tissue increase, with distance away from the National Security Complex (NSC), despite extensive source control efforts at the facility and within downstream riparian zones. Furthermore, dissolved methylmercury (d-MeHg) levels increase downstream from the NSC, especially during warm weather and/or high flow events. MSE performed four test series that focused on conversion of aqueous phase elemental mercury (Hg deg. A) to methyl mercury (MeHg) by algal-bacterial bio-films (periphyton) present in the stream-bed of LEFPC. Small (mg/L) quantities of un-sulphured molasses and peptone were added to some of the Hinds Creek samples to stimulate initial bacterial growth. Other Hinds Creek samples either were dosed with glutaraldehyde to preclude microbial growth, or were wrapped in aluminum foil to preclude Hg photochemical redox effects. The bench-scale testing for Phase II was completed August 2006. The final reporting and the planning for Phase III testing are in progress. (authors)

Byrne-Kelly, D.; Cornish, J.; Hart, A. [MSE Technology Applications, Inc., 200 Technology Way, Butte, MT (United States); Southworth, G. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Sims, L. [Bechtel Jacobs Company, Oak Ridge, TN (United States)

2007-07-01

85

Mercury Levels along the Food Chain and Risk for Exposed Populations  

Microsoft Academic Search

Mercury was not regarded as a pollutant of primary importance until many deaths due to mercury poisoning occurred in the 1950s. More recently, adverse health effects have been documented at relatively low exposure levels, and monitoring data must now be interpreted in this light. The Mediterranean basin has been studied in great detail over the past 20 years because of

A. Renzoni; F. Zino; E. Franchi

1998-01-01

86

Determination of mercury in fish tissue using a minianalyzer based on cold vapor atomic absorption spectrometry at the 184.9 nm line.  

PubMed

A sensitive method was proposed and optimized for the determination of total mercury in fish tissue by using wet digestion, followed by cold vapor atomic absorption spectrometry (CVAAS) at the main resonance line of mercury (184.9 nm). The measurements were made using a new type of a non-dispersive mercury minianalyzer. This instrument was initially designed and built for atmospheric mercury-vapor detection. For determining mercury in aqueous samples, the minianalyzer was linked with a mercury/hydride system, Perkin Elmer Model MHS-10. To check the method, the analyzed samples were spiked with a standard solution of mercury. The recoveries of mercury spiked to wet fish tissue were >90% for 0.5 - 0.8 g samples. The results showed a better sensitivity (about 2.5 times higher) when using the mercury absorption line at 184.9 nm compared with the sensitivity obtained by conventional CVAAS at 253.7 nm. PMID:17878589

Rizea, Maria-Cristina; Bratu, Maria-Cristina; Danet, Andrei Florin; Bratu, Adrian

2007-09-01

87

Dietary Predictors of Maternal Prenatal Blood Mercury Levels in the ALSPAC Birth Cohort Study  

PubMed Central

Background: Very high levels of prenatal maternal mercury have adverse effects on the developing fetal brain. It has been suggested that all possible sources of mercury should be avoided. However, although seafood is a known source of mercury, little is known about other dietary components that contribute to the overall levels of blood mercury. Objective: Our goal was to quantify the contribution of components of maternal diet to prenatal blood mercury level. Methods: Whole blood samples and information on diet and sociodemographic factors were collected from pregnant women (n = 4,484) enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). The blood samples were assayed for total mercury using inductively coupled plasma dynamic reaction cell mass spectrometry. Linear regression was used to estimate the relative contributions of 103 dietary variables and 6 sociodemographic characteristics to whole blood total mercury levels (TBM; untransformed and log-transformed) based on R2 values. Results: We estimated that maternal diet accounted for 19.8% of the total variation in ln-TBM, with 44% of diet-associated variability (8.75% of the total variation) associated with seafood consumption (white fish, oily fish, and shellfish). Other dietary components positively associated with TBM included wine and herbal teas, and components with significant negative associations included white bread, meat pies or pasties, and french fries. Conclusions: Although seafood is a source of dietary mercury, seafood appeared to explain a relatively small proportion of the variation in TBM in our UK study population. Our findings require confirmation, but suggest that limiting seafood intake during pregnancy may have a limited impact on prenatal blood mercury levels. Citation: Golding J, Steer CD, Hibbeln JR, Emmett PM, Lowery T, Jones R. 2013. Dietary predictors of maternal prenatal blood mercury levels in the ALSPAC birth cohort study. Environ Health Perspect 121:1214–1218;?http://dx.doi.org/10.1289/ehp.1206115 PMID:23811414

Steer, Colin D.; Hibbeln, Joseph R.; Emmett, Pauline M.; Lowery, Tony; Jones, Robert

2013-01-01

88

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

89

Fish consumption and hair mercury levels in women of childbearing age, Martin County, Florida.  

PubMed

The health effects of mercury in humans are mostly on the developing nervous system. Pregnant women and women who are breastfeeding must be targeted in order to decrease mercury exposure to the populations at highest risk-infants, unborn fetuses, and young children. This purpose of this study is to understand the demographics of fish-consumption patterns among women of childbearing age (including pregnant women) in Martin County, Florida, and to analyze the associations of mercury levels in participants' hair with socio-demographic variables in order to better design prevention messages and campaigns. Mercury concentrations in hair samples of 408 women ages 18-49 were assessed. Data on demographic factors, pregnancy status, fish consumption, and awareness of fish advisories were collected during personal interviews. Data were analyzed using descriptive statistics and multivariate logistic regression. The geometric and arithmetic means of hair mercury concentration were 0.371 and 0.676 µg/g of hair. One-fourth of the respondents had a concentration ?1 µg/g of hair. Consuming a higher number of fish meals per month, consumption of commercially purchased or locally caught fish higher in mercury, White race and income ?$75,000 were positively associated with the likelihood of having higher hair mercury levels. This study confirms the existence of a higher overall mean hair mercury level and a higher percentage of women with ?1 µg/g hair mercury level than those reported at the national level and in other regional studies. This suggests the need for region-specific fish consumption advisories to minimize mercury exposure in humans. PMID:24807406

Nair, Anil; Jordan, Melissa; Watkins, Sharon; Washam, Robert; DuClos, Chris; Jones, Serena; Palcic, Jason; Pawlowicz, Marek; Blackmore, Carina

2014-12-01

90

Hair mercury level of coastal communities in Malaysia: a linkage with fish consumption  

Microsoft Academic Search

Hair mercury level was assessed in four coastal communities in Malaysia with relation to fish consumption between gender,\\u000a age, and rural and urban area. Mercury level was found at a range of 0.01–21.00 (?g\\/g dry wt). The average mercury levels\\u000a were 13.69, 10.85, 9.94, and 6.78 ?g\\/g dry wt for communities in Kedah, Terengganu, Johor, and Selangor, respectively. The\\u000a same order

Parvaneh Hajeb; Jinap Selamat; Ahmad Ismail; Fatimah Abu Bakar; Jamilah Bakar; Hanifah Nuryani Lioe

2008-01-01

91

Localizing Organomercury Uptake And Accumulation in Zebrafish Larvae at the Tissue And Cellular Level  

SciTech Connect

Using synchrotron x-ray fluorescence mapping, we have examined the uptake and localization of organic mercury in zebrafish larvae. Strikingly, the greatest accumulation of methyl and ethyl mercury compounds was highly localized in the rapidly dividing lens epithelium, with lower levels going to brain, optic nerve, and various other organs. The data suggest that the reported impairment of visual processes by mercury may arise not only from previously reported neurological effects, but also from direct effects on the ocular tissue. This novel approach is a powerful tool for directly investigating the molecular toxicology of heavy metals, and should be equally applicable to the study of a wide range of elements in developing embryos.

Korbas, M.; Blechinger, S.R.; Krone, P.H.; Pickering, I.J.; George, G.N.

2009-05-20

92

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.

93

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

94

Methylmercury levels and bioaccumulation in the aquatic food web of a highly mercury-contaminated reservoir.  

PubMed

The low Ebro River basin (NE Spain) represents a particular case of chronic and long-term mercury pollution due to the presence of an industrial waste (up to 436 ?g/g of Hg) coming from a chlor-alkali plant Albeit high total mercury (THg) levels have been previously described in several aquatic species from the surveyed area, methylmercury (MeHg) values in fish individuals have never been reported. Accordingly, in order to investigate bioaccumulation patterns at different levels of the aquatic food web of such polluted area, crayfish and various fish species, were analysed for THg and MeHg content. At the hot spot, THg mean values of crayfish muscle tissue and hepatopancreas were 10 and 15 times, respectively, greater than the local background level. Higher mean THg concentrations were detected in piscivorous (THg=0.848 ± 0.476 ?g/g wet weight (ww); MeHg=0.672 ± 0.364 ?g/g ww) than in non-piscivorous fish (THg=0.305 ± 0.163 ?g/g ww; MeHg=0.278 ± 0.239 ?g/g ww). Although these results indicated that THg in fish increased significantly with increasing trophic position, the percentage of the methylated form of Hg was not strongly influenced by differences in relative trophic position. This is an important finding, since the fraction of THg as MeHg in the top fish predator was unexpectedly lower than for other species of the aquatic food chain. Moreover, mean THg concentrations in piscivorous fish exceed the maximum level recommended for human consumption. From our findings, it is clear that for this specific polluted system, speciation becomes almost mandatory when risk assessment is based on MeHg, since single measurements of THg are inadequate and could lead to an over- or under-estimation of contamination levels. PMID:21658770

Carrasco, Luis; Benejam, Lluís; Benito, Josep; Bayona, Josep M; Díez, Sergi

2011-10-01

95

Total mercury in muscle tissue of five shark species from Brazilian offshore waters: effects of feeding habit, sex, and length.  

PubMed

This study was carried out to assess mercury levels in fish from Brazilian offshore waters. Generally sharks have relatively high mercury levels which are also affected by diet, age (associated with length), and sex. Total mercury levels were determined in five shark species with different habits (Carcharhinus signatus, Mustelus canis, Mustelus norrisi, Squalus megalops, and Squalus mitsukurii) which were collected during 1997 in southern Brazil's offshore waters. The highest mercury concentrations, all above the limit established by Brazilian legislation (0.5 microg.g(-1)), were detected in piscivorous species (C. signatus, S. megalops, and S. mitsukurii) with averages of 1.77+/-0.56, 1.9+/-0.58, and 2.22+/- 0.72 microg.g(-1), respectively, while species that feed mainly on invertebrates (M. canis and M. norrisi) had averages of 0.41+/-0.35 and 0.36+/-0.28 microg.g(-1). These results indicate that feeding habits influence total mercury level in sharks. Methylmercury (as a percentage of total mercury) determined in S. mitsukurii and M. canis also showed an influence of feeding habit. Positive correlations between mercury concentration and length were statistically significant (P<0.05) for all species, except M. norrisi. Although mercury levels were generally higher in males than in females for all species (with the exception of S. mitsukurii), a statistically significant correlation was observed only for M. canis. PMID:12176009

Penedo de Pinho, Alexandra; Davée Guimarães, Jean Remy; Martins, Agnaldo S; Costa, P A S; Olavo, G; Valentin, Jean

2002-07-01

96

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

97

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

98

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

99

Low-Cost Options for Moderate Levels of Mercury Control  

SciTech Connect

On March 15, 2005, EPA issued the Clean Air Mercury Rule, requiring phased-in reductions of mercury emissions from electric power generators. ADA-ES, Inc., with support from DOE/NETL and industry partners, is conducting evaluations of EPRI's TOXECON II{trademark} process and of high-temperature reagents and sorbents to determine the capabilities of sorbent/reagent injection, including activated carbon, for mercury control on different coals and air emissions control equipment configurations. DOE/NETL targets for total mercury removal are {ge}55% (lignite), {ge}65% (subbituminous), and {ge}80% (bituminous). Based on work done to date at various scales, meeting the removal targets appears feasible. However, work needs to progress to more thoroughly document and test these promising technologies at full scale. This is the final site report for tests conducted at MidAmerican's Louisa Station, one of three sites evaluated in this DOE/NETL program. The other two sites in the program are MidAmerican's Council Bluff Station and Entergy's Independence Station. MidAmerican's Louisa Station burns Powder River Basin (PRB) coal and employs hot-side electrostatic precipitators with flue gas conditioning for particulate control. This part of the testing program evaluated the effect of reagents used in the existing flue gas conditioning on mercury removal.

Sharon Sjostrom

2006-03-31

100

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

101

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

102

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

103

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...

104

Consumption of tomato products is associated with lower blood mercury levels in Inuit preschool children.  

PubMed

Some evidence suggests that various diet components and nutrients, including vegetables, fruit and food-derived antioxidants, could mitigate contaminant exposure and/or adverse health effects of contaminants. To examine the effect of the consumption of tomato products on blood mercury levels in Inuit preschool children, 155 Inuit children (25.0±9.1months) were recruited from 2006-2008 in Nunavik childcare centers (northern Québec, Canada). Food frequency questionnaires were completed at home and at the childcare center, and total blood mercury concentration was measured by inductively coupled plasma-mass spectrometry. Multivariate regression analysis was performed after multiple imputation. The median blood concentration of mercury was 9.5nmol/L. Age, duration of breastfeeding, annual consumption frequency of seal meat, and monthly consumption frequency of tomato products were significant predictors of blood mercury levels, whereas annual consumption frequencies of beluga muktuk, walrus, Arctic char, and caribou meat were not. Each time a participant consumed tomato products during the month before the interview was associated with a 4.6% lower blood mercury level (p=0.0005). All other significant predictors in the model were positively associated with blood mercury levels. Further studies should explore interactions between consumption of healthy store-bought foods available in Arctic regions and contaminant exposure. PMID:23127601

Gagné, Doris; Lauzière, Julie; Blanchet, Rosanne; Vézina, Carole; Vaissière, Emilie; Ayotte, Pierre; Turgeon O'Brien, Huguette

2013-01-01

105

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

106

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

107

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

108

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

109

Analysis of total mercury in human tissues prepared by microwave decomposition using a hydride generator system coupled to an atomic absorption spectrometer  

Microsoft Academic Search

A fast and efficient procedure has been developed for the analysis of total mercury in human tissues and blood using a hydride vapor generator system coupled to an atomic absorption spectrometer (HVG–AA). Tissue and blood samples were digested in a pressurized microwave decomposition system and the digest diluted prior to formation of free mercury vapor and analysis by atomic absorption.

Xenophon Cominos; Sotiris Athanaselis; Artemis Dona; Antonios Koutselinis

2001-01-01

110

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

111

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

112

Mercury, Cadmium, and Lead Levels in Human Placenta: A Systematic Review  

PubMed Central

Background: Placental tissue may furnish information on the exposure of both mother and fetus. Mercury (Hg), cadmium (Cd), and lead (Pb) are toxicants of interest in pregnancy because they are associated with alterations in child development. Objectives: The aim of this study was to summarize the available information regarding total Hg, Cd, and Pb levels in human placenta and possible related factors. Methods: We performed a systematic search of PubMed/MEDLINE, EMBASE, Lilacs, OSH, and Web of Science for original papers on total Hg, Cd, or Pb levels in human placenta that were published in English or Spanish (1976–2011). Data on study design, population characteristics, collection and analysis of placenta specimens, and main results were extracted using a standardized form. Results: We found a total of 79 papers (73 different studies). Hg, Cd, and Pb levels were reported in 24, 46, and 46 studies, respectively. Most studies included small convenience samples of healthy pregnant women. Studies were heterogeneous regarding populations selected, processing of specimens, and presentation of results. Hg concentrations > 50 ng/g were found in China (Shanghai), Japan, and the Faroe Islands. Cd levels ranged from 1.2 ng/g to 53 ng/g and were highest in the United States, Japan, and Eastern Europe. Pb showed the greatest variability, with levels ranging from 1.18 ng/g in China (Shanghai) to 500 ng/g in a polluted area of Poland. Conclusion: The use of the placenta as a biomarker to assess heavy metals exposure is not properly developed because of heterogeneity among the studies. International standardized protocols are needed to enhance comparability and increase the usefulness of this promising tissue in biomonitoring studies. PMID:22591711

Esteban-Vasallo, María D.; Aragonés, Nuria; Pollan, Marina; López-Abente, Gonzalo

2012-01-01

113

Comparative effects of copper, cadmium and mercury on tissue glycogen of the catfish, Heteropneustes fossils (Bloch).  

PubMed

Copper (Cu), cadmium (Cd) and mercury (Hg) at concentrations of 12.5 mg/l, caused a decline in the glycogen level of liver, muscle, brain and kidney of Heteropneustes fossilis. A significant increase in the glycogen content of brain was caused by low concentrations (5 and 7.5 mg/l) of both Cd and Hg 5 mg/l Cu raised the kidney glycogen level, while the same dose of Hg raised liver glycogen. It is suggested that heavy metals in low concentrations act through the endocrine system, creating hormone and/or enzyme imbalance. PMID:7090004

Srivastava, D K

1982-04-01

114

Assessment of total mercury levels in Clarias gariepinus from the Sagua la Grande River, Cuba.  

PubMed

Total mercury levels (Thg) were quantified in Clarias gariepinus captured from the Sagua la Grande River (Cuba) in the vicinity of an active chlor-alkali plant, and relationships among place of capture; fish size, weight, and sex; and THg levels were assessed. THg levels ranged from 67 to 375 ng/g ww in collected fish, never exceeding the Cuban recommended maximum limit for fish consumption of 500 ng/g ww. No significant correlation was observed between mercury levels and fish allometric characteristics (p < 0.05); however, levels were significantly higher in fish captured below the chlor-alkali facility, suggesting a connection between mercury bioaccumulation and plant discharges. PMID:18841320

De La Rosa, D; Lima, L; Olivares-Rieumont, S; Graham, D W; Enriquez, I; Diaz, O; Bastías, J M; Muñoz, O

2009-01-01

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, 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

116

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

...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...

2012-07-01

117

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

...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...

2013-07-01

118

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

...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...

2014-07-01

119

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

...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...

2011-07-01

120

Mercury in Freshwater Fish of Northeast North America – A Geographic Perspective Based on Fish Tissue Monitoring Databases  

Microsoft Academic Search

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

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

2005-01-01

121

Assessment of Caudal Fin Clips as a Non-lethal Technique for Predicting Muscle Tissue Mercury Concentrations in Largeouth Bass  

EPA Science Inventory

The statistical relationship between total mercury (Hg) concentration in clips from the caudal fin and muscle tissue of largemouth bass (Micropterus salmoides) from 26 freshwater sites in Rhode Island, USA was developed and evaluated to determine the utility of fin clip analysis ...

122

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...

123

Relationship between the prenatal exposure to low-level of mercury and the size of a newborn’s cerebellum  

Microsoft Academic Search

Exposure to methylmercury at any stage of central nervous system development could induce alterations and result in severe congenital abnormalities. Total mercury level in maternal hair during pregnancy correlates well with blood levels of methylmercury and with total mercury levels in fetal brain.A prospective study has been conducted and a total of 137 childbearing women living at the coastal region

I. Bilic Cace; A. Milardovic; I. Prpic; R. Krajina; O. Petrovic; P. Vukelic; Z. Spiric; M. Horvat; D. Mazej; J. Snoj

2011-01-01

124

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

PubMed

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 (<1.3ng/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 (20.7bar). However, higher operating pressures (?34.5bar) 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?m to 0.74±0.2?m after UF. PMID:22410725

Urgun-Demirtas, Meltem; Benda, Paul L; Gillenwater, Patricia S; Negri, M Cristina; Xiong, Hui; Snyder, Seth W

2012-05-15

125

Influence of Methylmercury from Tributary Streams on Mercury Levels in Savannah River Asiatic Clams  

SciTech Connect

Average methylmercury levels in five Savannah River tributary streams sampled 11 times over two years were nearly twice as high as in the Savannah River. Total mercury levels in the tributaries did not differ significantly from the river. All of the tributaries drained extensive wetlands that would be expected to support comparatively high rates of methylation. Mercury concentrations in Asiatic clams (Corbicula fluminea) collected from the discharge plumes of Savannah River tributaries were significantly higher than in Asiatic clams collected from the Savannah River upstream from the tributary mouths . These results indicate that streams draining wetlands into coastal plain rivers can create localized areas of elevated methylmercury with resulting increases in the mercury levels of river biota.

Paller, M.H.

2004-03-01

126

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

127

Tissue distribution of different mercurial compounds analyzed by the improved FI-CVAAS.  

PubMed

Mercury contents in biological samples can be measured by cold vapor atomic absorption spectroscopy combined with the flow-injection analysis system. However, water vapor in the absorption cell attenuated and distorted the signals. This study described the strategy to overcome this problem by adding an additional gas-liquid separator after the mixing/separator assembly. This modification can efficiently minimize the moisture in the transfer line and in the absorption cell. This improved technique was adopted to study the differential tissue distribution of methylmercury and HgS after oral administration to mice for five consecutive days. The present study suggests that the insoluble HgS (the main constituent of a Chinese mineral drug, cinnabar, used as a sedative) can still be absorbed from gastrointestinal tract and distributed to various tissues including the brain. As compared with methylmercury, the total amount of HgS accumulated in the tissues ranging about one five-thousandth of methylmercury, which is well correlated with the biological activity of HgS reported previously. PMID:12166816

Yen, Cheng-Chieh; Liu, Shing-Hwa; Chen, Wen-Kang; Lin, Ruey-Hseng; Lin-Shiau, Shoei-Yn

2002-01-01

128

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

129

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

130

Symptoms of intoxication in dentists associated with exposure to low levels of mercury.  

PubMed

The present study examined the effects of occupational exposure of a group of dentists to low levels of mercury. The study population consisted of 106 dentists and 94 general practitioners (referent group), from private and public clinics in Shiraz city. Subjects were requested to complete a questionnaire on demographic variables, suspicious symptoms of intoxication and work practices. Additionally, atmospheric and urinary concentrations of mercury were measured by Atomic Absorption Spectroscopy technique. The data were analysed by ?(2) test, independent sample t-test and multivariate logistic regression analysis, where applicable. Both groups were similar as far as most demographic and socioeconomic variables, but age and number of personal amalgam fillings, were concerned. Median of atmospheric concentration of mercury was found to be 3.35 ?g/m(3). Likewise, the urinary concentration of mercury in dentists was estimated to be 3.16 ?g/g creatinine. This value was significantly higher than that of the referent group. Similarly, analysis of the data revealed that neuropsychological, muscular, respiratory, cardiovascular and dermal symptoms were more prevalent in dentists. Our findings indicate that occupational exposure of dentists to mercury, even at low levels, is associated with a significant increase in the prevalence of symptoms of intoxication. PMID:21173523

Neghab, Masoud; Choobineh, Alireza; Hassan Zadeh, Jafar; Ghaderi, Ebrahim

2011-01-01

131

Ecological characterization of streams, and fish-tissue analysis for mercury and lead at selected locations, Fort Gordon, Georgia, June 1999 to May 2000  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Ga., documented the ecological condition of selected water-bodies on the Fort Gordon military installation from June 1999 to May 2000. This study includes stream-habitat assessments, aquatic invertebrate and fish-community surveys in selected stream reaches, and analyses of mercury and lead concentrations in largemouth bass (Micropterous salmoides) muscle tissue from three impoundments. Assessment surveys indicate lower habitat value scores in some streams draining the more developed areas on Fort Gordon. A small tributary to Butler Creek--which drains parking lots associated with military motor pools and other impervious surfaces--is characterized by moderate levels of bank erosion and excess sediment in the stream channel compared to reference sites. Four other stream reaches are more similar to reference streams in respect to habitat conditions. Invertebrate communities in streams draining these urbanized watersheds are inhabited by 13 to 16 taxa per reach; whereas, 23 and 33 taxa were collected from the two reference stream reaches. Measures of invertebrate abundance, taxa richness, Ephemeroptera, Plecoptera, and Tricoptera Index are lower in streams draining urbanized watersheds. Measures of community similarity also indicate differences between streams draining urbanized areas and reference streams. Streams draining developed areas on Fort Gordon are inhabited by 3 to 10 fish species and included more species regarded as tolerant of degraded water-quality conditions; whereas, the two reference stream reaches support 4 and 10 species, respectively, including one species considered intolerant of degraded water-quality conditions. Mercury was detected in all largemouth bass collected from three impoundments on Fort Gordon. Wet-weight mercury concentrations in fish tissue analyzed from all sites range from 0.08 micrograms per gram to 1.33 micrograms per gram. Median mercury concentrations in fish tissue are 0.83 micrograms per gram at Soil Erosion Lake, 0.72 micrograms per gram at Lower Leitner Lake, and 0.22 micrograms per gram at Gordon Lake. Median mercury concentrations in fish tissue analyzed from Soil Erosion Lake and Lower Leitner Lake are more than two times higher than U.S. Environmental Protection Agency recommendation of 0.3 micrograms per gram for fish consumption. Lead concentrations are below the minimum reporting limit for all specimens analyzed from reservoirs sampled at Fort Gordon.

Gregory, M. Brian; Stamey, Timothy C.; Wellborn, John B.

2001-01-01

132

Mercury in Morelet's Crocodile Eggs from Northern Belize  

Microsoft Academic Search

Recent studies have examined mercury accumulation in crocodilians. However, though most researchers have focused on tissue\\u000a concentrations, few have examined mercury levels in crocodilian eggs. In July 1995, we analyzed mercury in 31 nonviable Morelet's\\u000a crocodile (Crocodylus moreletii) eggs collected from eight nests across three localities in northern Belize. All eggs were found to contain mercury. Based\\u000a on an individual

T. R. Rainwater; B. M. Adair; S. G. Platt; T. A. Anderson; G. P. Cobb; S. T. McMurry

2002-01-01

133

Mercury species in lymphoid and non-lymphoid tissues after exposure to methyl mercury: Correlation with autoimmune parameters during and after treatment in susceptible mice  

SciTech Connect

Methylmercury (MeHg) is present in the environment as a result of the global cycling of mercury, although anthropogenic sources may dramatically increase the availability in confined geographical areas. Accumulation of MeHg in the aquatic food chain is the dominating way of exposure in mammals, which accumulate MeHg in all organs, including Brain. Demethylation has been described in the organs, especially in phagocytic cells, but mainly in the flora of the intestinal tract. While most of the inorganic mercury (Hg{sup 2+}) formed in the intestine is excreted, a fraction is reabsorbed which together with the local demethylation increases the organ Hg{sup 2+} concentration. MeHg is a well-known immunosuppressive agent, while Hg{sup 2+} is associated with immunostimulation and autoimmunity especially in genetically susceptible rodents, creating a syndrome, i.e. mercury-induced autoimmunity (HgIA). This study aimed at exploring the effect of MeHg with regard to HgIA, and especially the immunological events after stopping treatment, correlated with the presence of MeHg and Hg{sup 2+} in the organs. Treatment of A.SW mice for 30 days with 4.2 mg MeHg/L drinking water (corresponding to approximately 420 {mu}g Hg/kg body weight/day) caused all the HgIA features observed after primary treatment with inorganic Hg, except systemic immune complex deposits. The total Hg concentration was 5-fold higher in the kidneys as compared with lymph nodes, but the fraction of Hg{sup 2+} was similar (17-20%). After stopping treatment, the renal and lymph node MeHg concentration declined according to first order kinetics during the initial 4-6 weeks, but then slower. A similar decline in the organ Hg{sup 2+} concentration occurred during the initial 2 weeks after stopping treatment but then ceased, causing the Hg{sup 2+} concentration to exceed that of MeHg in the lymph nodes and kidneys after 3 and 8 weeks, respectively. The selective increase in lymph node Hg{sup 2+} fraction is likely to be due to demethylation of MeHg in the macrophage-rich lymphoid tissue. The major autoantibody in HgIA, anti-fibrillarin antibodies, tended to increase during the initial 6 weeks after stopping treatment, while all other HgIA features including antichromatin antibodies declined to control levels after 2-4 weeks. This indicates differences in either dose requirement or induction mechanisms for the different HgIA parameters. The selective accumulation of Hg{sup 2+} in lymph nodes following MeHg treatment should be taken into account when the effect of MeHg on the immune system is evaluated.

Havarinasab, Said [Molecular and Immunological Pathology (AIR), Department of Molecular and Clinical Medicine, Linkoeping University, SE-581 85 Linkoeping (Sweden); Bjoern, Erik [Department of Chemistry, Analytical Chemistry, Umea University, SE-901 87 Umea (Sweden); Nielsen, Jesper B. [Department of Environmental Medicine, University of Southern Denmark, DK-5230 Odense (Denmark); Hultman, Per [Molecular and Immunological Pathology (AIR), Department of Molecular and Clinical Medicine, Linkoeping University, SE-581 85 Linkoeping (Sweden)]. E-mail: perhu@imk.liu.se

2007-05-15

134

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

135

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

136

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.

137

Mercury in polar bears from Alaska  

SciTech Connect

Alaskan polar bear (Ursus maritimus) muscle and liver samples collected in 1972 were analyzed for total mercury. Bears north of Alaska had more mercury than bears west of Alaska. The only difference between young and adult animals was in the northern area where adults had more mercury in liver tissue than young animals. Levels were probably not high enough to be a serious threat to bears.

Lentfer, J.W.; Galster, W.A.

1987-04-01

138

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

139

The presence of mercury selenide in various tissues of the striped dolphin: evidence from ?-XRF-XRD and XAFS analyses.  

PubMed

Marine mammals accumulate mercury in their tissues at high concentration and detoxify by forming mercury selenide (HgSe, tiemannite) mainly in the liver. We investigated the possibility of formation of HgSe in various tissues (liver, kidney, lung, spleen, pancreas, muscle and brain) other than the liver of the striped dolphin (Stenella coeruleoalba). We applied a combination method of micro-X-ray fluorescence (?-XRF) imaging and micro-X-ray diffraction (?-XRD) using a synchrotron radiation X-ray microbeam to analyze the tissue samples directly with minimal sample preparation. By this method, many accumulation points for Hg and Se on a micron scale were found in thin sections of the spleen and liver tissue and consequently, the XRF spectra and the XRD pattern of the hot spots confirmed the presence of tiemannite, HgSe. On the other hand, the insoluble fractions after enzyme digestion of the nuclear and mitochondrial fractions of all tissues were subjected to X-ray absorption fine structure (XAFS) analysis. XAFS analysis confirmed the presence of HgSe in all the tissues examined (liver, kidney, lung, spleen, pancreas, muscle and brain) of the striped dolphin. The presence of HgSe in all the tissues examined suggests that Se would be involved in the detoxification process of Hg in various tissues other than the liver. This contribution seems to be large especially in the liver and spleen but relatively small in the kidney, pancreas and brain, because the proportion of insoluble fraction containing HgSe was lower in these tissues (25 to 46%). This is the first report on the presence of tiemannite HgSe in various tissues of marine mammals. PMID:21468440

Nakazawa, Emiko; Ikemoto, Tokutaka; Hokura, Akiko; Terada, Yasuko; Kunito, Takashi; Tanabe, Shinsuke; Nakai, Izumi

2011-07-01

140

Mercury pollution in Malaysia.  

PubMed

Although several studies have been published on levels of mercury contamination of the environment, and of food and human tissues in Peninsular Malaysia, there is a serious dearth of research that has been performed in East Malaysia (Sabah and Sarawak). Industry is rapidly developing in East Malaysia, and, hence, there is a need for establishing baseline levels of mercury contamination in environmental media in that part of the country by performing monitoring studies. Residues of total mercury and inorganic in food samples have been determined in nearly all previous studies that have been conducted; however, few researchers have analyzed samples for the presence of methlymercury residues. Because methylmercury is the most toxic form of mercury, and because there is a growing public awareness of the risk posed by methylmercury exposure that is associated with fish and seafood consumption, further monitoring studies on methylmercury in food are also essential. From the results of previous studies, it is obvious that the economic development in Malaysia, in recent years, has affected the aquatic environment of the country. Primary areas of environmental concern are centered on the rivers of the west Peninsular Malaysian coast, and the coastal waters of the Straits of Malacca, wherein industrial activities are rapidly expanding. The sources of existing mercury input to both of these areas of Malaysia should be studied and identified. Considering the high levels of mercury that now exists in human tissues, efforts should be continued, and accelerated in the future, if possible, to monitor mercury contamination levels in the coastal states, and particularly along the west Peninsular Malaysian coast. Most studies that have been carried out on mercury residues in environmental samples are dated, having been conducted 20-30 years ago; therefore, the need to collect much more and more current data is urgent. Furthermore, establishing baseline levels of mercury exposure to humans in Malaysia will be useful in establishing the levels at which detrimental effects in both humans and marine life may occur, and therefore the levels at which warning should be raised or limits established. In particular, we believe that two or three monitoring centers should be established in Peninsular Malaysia, and one in East Malaysia for the specific purpose of monitoring for the presence of hazardous environmental chemicals, and particularly monitoring for heavy metals such as mercury that reach food that is subject to consistent human consumption. PMID:22610296

Hajeb, Parvaneh; Jinap, S; Ismail, Ahmad; Mahyudin, Nor Ainy

2012-01-01

141

Mercury vapor pressure of flue gas desulfurization scrubber suspensions: effects of pH level, gypsum, and iron.  

PubMed

Calcium-based scrubbers designed to absorb HCl and SO(2) from flue gases can also remove oxidized mercury. Dissolved mercury halides may have an appreciable partial vapor pressure. Chemical reduction of the dissolved mercury may increase the Hg emission, thereby limiting the coremoval of mercury in the wet scrubbing process. In this paper we evaluate the effects of the pH level, different gypsum qualities, and iron in flue gas desulfurization (FGD) scrubber suspensions. The impact of these parameters on mercury vapor pressure was studied under controlled laboratory conditions in model scrubber suspensions. A major influence is exerted by pH values above 7, considerably amplifying the mercury concentration in the vapor phase above the FGD scrubber suspension. Gypsum also increases the mercury re-emission. Fe(III) decreases and Fe(II) increases the vapor pressure significantly. The consequences of the findings for a reliable coremoval of mercury in FGD scrubbers are discussed. It is shown that there is an increased risk of poor mercury capture in lime-based FGD scrubbers in comparison to limestone FGD scrubbers. PMID:22324514

Schuetze, Jan; Kunth, Daniel; Weissbach, Sven; Koeser, Heinz

2012-03-01

142

Determination of total mercury in chicken feed, its translocation to different tissues of chicken and their manure using cold vapour atomic absorption spectrometer.  

PubMed

In this study, the contents of total mercury (Hg) present in poultry feed, tissues of broiler chicken and manure were assessed. For this purpose, chicken feeds (five brands), different tissues of broiler chicken of two age groups (1-3 and 4-6 week) and manure samples were collected from five commercial poultry farms of Hyderabad, Pakistan. The Hg concentrations in feeds, chicken tissues (leg, muscle, liver and heart) and manure samples were determined by CVAAS, prior to microwave assisted acid digestion in closed vessels. For validation, a certified reference material, DORM-2 was used. The limit of detection and quantitation were 0.117 and 0.382 microg/kg, respectively The Hg concentration in different chicken feed were found in the range of 8.57-16.5 microg/kg. The concentration of Hg in chicken tissues were found in the range of 2.54-5.54 microg/kg (liver), 1.27-3.86 microg/kg (muscles) and 2.13-3.27 microg/kg (heart). The bioaccumulation factors (BAF) for Hg in different tissues were found in the range of 0.092-0.269. The obtained data shows the high correlation coefficient between feed and manure, while low r-values were obtained between Hg levels in feed and tissues of broiler chicken of two age groups. PMID:20304027

Shah, A Q; Kazi, T G; Baig, J A; Afridi, H I; Kandhro, G A; Khan, S; Kolachi, N F; Wadhwa, S K

2010-06-01

143

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 exposure, and in total 8731 teeth of polar bears were analysed. Dental Hg levels ranged from 0.6 to 72.3 ng

Paris-Sud XI, Université de

144

Mercury burden and health impairment in dental auxilaries. Final report  

SciTech Connect

An effort was made to develop a safe and effective x-ray fluorescence system for monitoring mercury and other elements in human tissues in-situ, to determine mercury levels in 207 dental auxiliaries exposed to dental amalgam on the job, to evaluate mercury in matching nonexposed populations and in 298 dentists using mercury amalgam, and to evaluate deficiencies in central and peripheral nervous systems resulting from the mercury exposure. Mercury levels were below 20 micrograms/gram in 60% of the dentists and 90% of the dental auxiliaries. Dentists with the higher mercury concentrations in their heads or wrists had considerably longer median motor distal latencies and median F-wave latency. Five of them demonstrated abnormalities consistent with carpal tunnel syndrome; seven had polyneuropathies defined as reduced motor or sensory conduction velocities of response amplitudes in two or more nerves. Neuropsychological tests indicated both groups of dental workers were adversely affected by mercury exposure.

Shapiro, I.M.; Bloch, P.; Ship, I.I.; Spitz, L.; Summer, A.

1988-01-01

145

Surveying Mercury Levels in Hair, Blood and Urine of under 7-Year Old Children from a Coastal City in China  

PubMed Central

Aim: The average mercury load in children under 7-years old was determined in a populated but not overly industrial coastal area in China. Methods: 395 blood samples, 1072 urine samples, and 581 hair samples were collected from 1076 children, aged 0 to 6 years, from eight representative communities of Xiamen, China. Mercury levels in the samples were surveyed. Results: The 95% upper limits of mercury in blood, urine, and hair for the children were 2.30, 1.50 and 2100.00 ?g/kg, respectively. Levels tended to increase with age. Correlation analyses showed that mercury levels in blood and urine correlated with those in hair (n = 132), r = 0.49, p < 0.0001 and r = 0.20, p = 0.0008; however, blood mercury levels did not correlate with urine levels (n = 284), r = 0.07, p = 0.35. Conclusions: Surveying the average mercury load in children 0 to 6 years, and the 95% upper limit value of mercury in their blood, urine, and hair should help guide risk assessment and health management for children. PMID:25419876

Chen, Guixia; Chen, Xiaoxin; Yan, Chonghuai; Wu, Xingdong; Zeng, Guozhang

2014-01-01

146

Mercury contamination in human hair and some marine species from Sfax coasts of Tunisia: levels and risk assessment.  

PubMed

The aim of this study was to measure the mercury (Hg) contents of three marine fish and common seafood species (Diplodus annularis, Sarpa salpa and Sepia officinalis) at two sampling sites in the gulf of Gabes, i.e. Sidi Mansour (polluted site) and Kerkennah (control site). These species are frequently consumed by the population living at the Sfax coasts of Tunisia, particularly by the families of fisherman. Additionally, the hair mercury levels of 55 volunteers (28 women, 27 men) were analysed and the daily total mercury intake through the fish and seafood diet was estimated. The key findings were: (1) the mercury contents of the examined fish and seafood species frequently exceeded the regulatory guideline value of 0.5 mg/kg, (2) no site-specific differences in hair mercury contents were found, (3) fish and seafood consumption is probably the major contributor of mercury exposure in this population, (4) the daily mercury intake through frequent consumption of D. annularis exceeds the US EPA reference dose. Further studies are necessary to evaluate the health risks associated with such high mercury exposure levels in order to allow optimal counseling and therapy of the concerned population and to avoid future impairment of human health, particularly children's health. PMID:21136288

Mezghani-Chaari, Sawssan; Hamza, A; Hamza-Chaffai, A

2011-09-01

147

Mercury-resistant bacteria from salt marsh of Tagus Estuary: the influence of plants presence and mercury contamination levels.  

PubMed

Mercury (Hg) contamination of aquatic systems has been recognized as a global, serious problem affecting both wildlife and humans. High levels of Hg, in particular methylmercury (MeHg), were detected in surface sediments of Tagus Estuary. MeHg is neurotoxic and its concentration in aquatic systems is dependent upon the relative efficiency of reduction, methylation, and demethylation processes, which are mediated predominantly by the microbial community, in particular mercury-resistant (HgR) bacteria. Plants in contaminated ecosystems are known to take up Hg via plant roots. Therefore, the aims of this study were to (1) isolate and characterize HgR bacteria from a salt marsh of Tagus Estuary (Rosário) and (2) determine HgR bacteria levels in the rhizosphere and, consequently, their influence in metal cycling. To accomplish this objective, sediments samples were collected during the spring season in an area colonized by Sacocornia fruticosa and Spartina maritima and compared with sediments without plants. From these samples, 13 aerobic HgR bacteria were isolated and characterized morphologically, biochemically, and genetically, and susceptibility to Hg compounds, Hg(2+), and MeHg was assessed by determination of minimal inhibitory concentration (MIC). Genetically, the mer operon was searched by polymerase chain reaction (PCR) and 16S rRNA sequencing was used for bacterial identification. Results showed that the isolates were capable of growing in the presence of high Hg concentration with MIC values for HgCl2 and MeHgCl in the ranges of 1.7-4.2 ?g/ml and 0.1-0.9 ?g/ml, respectively. The isolates from sediments colonized with Sacocornia fruticosa displayed higher resistance levels compared to ones colonized with Spartina maritima. Bacteria isolates showed different capacity of Hg accumulation but all displayed Hg volatilization capabilities (20-50%). Mer operon was found in two isolates, which genetically confirmed their capability to convert Hg compounds by reducing them to Hg(0). Thus, these results are the first evidence of the relevance of interaction between bacteria and plants in Hg cycling in Tagus Estuary. PMID:25072727

Figueiredo, Neusa L L; Areias, Andreia; Mendes, Ricardo; Canário, João; Duarte, Aida; Carvalho, Cristina

2014-01-01

148

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

149

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

150

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

151

Inorganic mercury exposure, mercury-copper interaction, and DMPS treatment in rats.  

PubMed Central

The aim of this study was to evaluate the efficiency of oral treatment with sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) on reducing mercury deposits in rat kidney after chronic exposure to inorganic mercury. The effect on kidney copper levels was also evaluated. The results showed that after two months of exposure to 50 ppm of mercury (as mercuric chloride) the concentration of mercury in the kidney was 124 micrograms/g wet tissue. At the same time copper concentration rose from 11 to 77 micrograms/g. DMPS treatment caused 2- and almost 4-fold reduction of mercury and copper, respectively. This study demonstrates that chronic exposure to inorganic mercury may alter metabolism of copper and that DMPS is an effective means for reduction of both mercury and copper. PMID:7843122

Blanusa, M; Prester, L; Radi?, S; Kargacin, B

1994-01-01

152

Total mercury determination in different tissues of broiler chicken by using cloud point extraction and cold vapor atomic absorption spectrometry.  

PubMed

A cloud point extraction (CPE) method has been developed for the determination of total mercury (Hg) in different tissues of broiler chicken by cold vapor atomic absorption spectrometry (CVAAS). The broiler chicken tissues (leg, breast, liver and heart) were subjected to microwave assisted digestion in a mixture of nitric acid and hydrogen peroxide (2:1 ratio), prior to preconcentration by CPE. Various parameters such as the amount of ammonium O,O-diethyldithiophosphate (DDTP), concentrations of Triton X-114, equilibrium temperature, time and centrifugation have been studied in order to find the best conditions for the determination of mercury. For validation of proposed method a certified reference material, DORM-2 was used. No significant difference p>0.05 was observed between the experimental results and the certified values of CRM (paired t-test). The limit of detection and quantitation obtained under the optimal conditions were 0.117 and 0.382 microg/kg, respectively. The accumulation of Hg in different tissues were found in the order of, liver>muscles>heart. The concentration of Hg in chicken tissues were found in the range of 1.57-2.75, 1.40-2.27, 1.55-4.22, and 1.39-2.61 microg/kg in leg, breast, liver and heart, respectively. PMID:19766690

Shah, A Q; Kazi, T G; Baig, J A; Afridi, H I; Kandhro, G A; Arain, M B; Kolachi, N F; Wadhwa, S K

2010-01-01

153

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

154

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

155

Zinc, cadmium, mercury and selenium in polar bears (Ursus maritimus) from Central East Greenland  

SciTech Connect

Muscle, liver, and kidney tissues from 38 polar bears (Ursus maritimus) caught in the Scoresby Sound area, Central East Greenland, were analysed for zinc, cadmium, mercury and selenium. In general, cadmium concentrations were low in muscle, liver and kidney tissue. This finding can be explained by low cadmium levels in the blubber of ringed seals. The concentration of mercury in muscle tissue was low, whereas concentrations in liver and kidney tissue were relatively high. Mercury and cadmium were positively correlated with age in liver and kidney. Zinc was positively correlated with in kidney, and selenium was correlated with age in liver. Contrary to other marine mammals, polar bears had higher mercury levels in the kidneys than in the liver. In all three tissues polar bears had significantly lower cadmium levels than ringed seals from the same area. Mercury levels were significantly lower in the muscle tissue of polar bears than in ringed seals, where-as levels in the liver and kidney were significantly higher. The previous geographic trend for cadmium and mercury found in Canadian polar bears could be extended to cover East Greenland as well. Hence cadmium levels were higher in Greenland than in Canada, while the opposite was the case for mercury. Greenland polar bears had higher mercury and cadmium contents in livers and kidneys than polar bears from Svalbard. The mercury levels in muscle and liver tissue from polar bears from East Greenland were twice as high as found in bears from western Alaska, but half the levels found in northern Alaska. Cadmium and zinc were partially correlated in kidney tissue, and this was found for mercury and selenium as well. Cadmium and zinc showed molar ratios close to unity with the highest concentrations occurring in kidney tissue, while the levels of zinc exceeded cadmium in muscle and liver tissue by up to several decades. Mercury and selenium showed molar ratios close to unity in liver and kidneys. 56 refs., 5 figs., 6 tabs.

Dietz, R. [Greenland Environmental Research Institute, Copenhagen (Denmark); Born, E.W. [Greenland Fisheries Research Institute, Copenhagen (Denmark); Agger, C.T. [National Environmental Research Institute, Roskilde (Denmark); Nielsen, C.O. [Ravnsnaesvej, Birkerod (Denmark)

1995-02-01

156

Association between Low-level Mercury Exposure and Neurobehavioral Functions in Korean Adults Living in a Coastal City  

PubMed Central

Objectives The aim of this study was to determine the association between low-level mercury exposure and neurobehavioral functions in adults living in coastal regions of Korea. Methods We selected 172 adults aged 20-65 years living in a city in the coastal region of Korea. A sociodemographic survey was conducted, mercury levels in the blood, urine, and hair were measured, and the associations according to computerized neurobehavioral tests were determined using univariate analysis. After adjustment for associated variables, a multivariate linear regression analysis was performed. Results The geometric mean mercury levels in the blood, urine, and hair were 5.41 µg/L (range, 0.00-15.84 µg/L), 1.17 µg/g-creatinine (range, 0.00-32.86 µg/g-creatinine), and 1.37 mg/kg (range, 0.42-6.56 mg/kg), respectively. Variables that were associated with simple reaction time according to the neurobehavioral test results were age and urine mercury level. Variables associated with choice reaction time were the recent use of Korean traditional medicine and urine mercury level. Variables associated with the right-hand finger tapping speed test were age, gender, smoking behavior, education level, monthly household income, and urine mercury level. Variables associated with the left-hand finger tapping speed test were age, gender, education level, and urine mercury level. After adjustment for associated variables, there was no significant association between urine mercury level and simple reaction time (?=25.96; p=0.47), choice reaction time (?=50.37; p=0.32), or the number of left-hand finger taps (?=-1.54; p=0.21). However, urine mercury level was significantly associated with the number of right-hand finger taps (?=-3.86; p=0.01). Conclusions We found no evidence that low-level mercury exposure in adults is associated with deficits in neurobehavioral functions. A longer follow-up study is required to confirm this conclusion. PMID:24303351

Kim, Rock Bum; Kim, Byoung-Gwon; Kim, Yu-Mi; Hong, Young-Seoub; You, Chang-Hun

2013-01-01

157

[Mercury levels in fish consumed by the Sai Cinza indigenous community, Munduruku Reservation, Jacareacanga County, State of Pará, Brazil].  

PubMed

This study evaluated fish consumption and mercury levels in fish consumed by an indigenous community in the State of Pará. Eighty fish samples were collected (barbado, surubim, traíra, tucunaré, piranha, aruanã, caratinga, aracu, mandiá, jandiá, and pacu). Mercury analysis was performed using a Mercury Analyzer HG-3500. Average mercury concentration in carnivorous species was 0.293 (g/g (SD=0.104), while in non-carnivorous species it was 0.112 (g/g (SD=0. 036). Brazilian legislation establishes a maximum permissible limit of 0.5 (g/g for fish consumption. No significant correlation was found between fish length or weight and mercury concentration. Types of fish most frequently consumed by the community were tucunaré, pacu, jaraqui, traíra, aracu, matrinchã, and caratinga. Carnivorous species, especially tucunaré and traíra, amongst the most frequently eaten, had higher mercury levels than non-carnivorous species. Frequency of consumption is crucial to assess the risk of mercury contamination in communities who lack alternative food sources. PMID:10409785

Brabo, E D; Santos, E D; Jesus, I M; Mascarenhas, A F; Faial, K F

1999-01-01

158

Exon-level Expression Profiling of Ocular Tissues  

PubMed Central

The normal gene expression profiles of the tissues in the eye are a valuable resource for considering genes likely to be involved with disease processes. We profiled gene expression in ten ocular tissues from human donor eyes using Affymetrix Human Exon 1.0 ST arrays. Ten different tissues were obtained from six different individuals and RNA was pooled. The tissues included: retina, optic nerve head (ONH), optic nerve (ON), ciliary body (CB), trabecular meshwork (TM), sclera, lens, cornea, choroid/retinal pigment epithelium (RPE) and iris. Expression values were compared with publically available Expressed Sequence Tag (EST) and RNA-sequencing resources. Known tissue-specific genes were examined and they demonstrated correspondence of expression with the representative ocular tissues. The estimated gene and exon level abundances are available online at the Ocular Tissue Database. PMID:23500522

Wagner, Alex H.; Anand, Nikhil; Wang, Wan-Heng; Chatterton, Jon E.; Sun, Duo; Shepard, Allan; Jacobson, Nasreen; Pang, Iok-Hou; DeLuca, Adam; Casavant, Thomas L.; Scheetz, Todd E.; Mullins, Robert; Braun, Terry A.; Clark, Abbot F.

2013-01-01

159

Tissue Mercury Concentrations in Alligators ( Alligator mississippiensis ) from the Florida Everglades and the Savannah River Site, South Carolina  

Microsoft Academic Search

.   Mercury pollution is a serious problem in some areas of\\u000a the southeastern United States. Due to biomagnification, long-lived predators\\u000a should have high Hg concentrations in affected areas. American alligators\\u000a (Alligator mississippiensis) are important predators in many\\u000a southwestern wetlands, but little information is available on Hg\\u000a concentrations in this species. We collected tissues from alligators\\u000a inhabiting two sites in the

G. M. Yanochko; C. H. Jagoe; I. L. Brisbin Jr.

1997-01-01

160

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

161

Age-dependent lower or higher levels of hair mercury in autistic children than in healthy controls.  

PubMed

An association between autism and early life exposure to mercury is a hotly debated issue. In this study, 91 autistic Polish children, male and female, 3-4 and 7-9 years old, were compared to 75 age- and sex-matched healthy children with respect to: demographic, perinatal, clinical and developmental measures, parental age, birth order, morphometric measures, vaccination history, and hair mercury content. In demographic and perinatal measures there were no consistent differences between the autistic and control groups. Autistic children had a significantly greater prevalence of adverse reactions after vaccinations and abnormal development than controls. Between 45 and 80% of autistic children experienced developmental regress. Autistic children significantly differed from healthy peers in the concentrations of mercury in hair: younger autistics had lower levels, while older - higher levels than their respective controls. The results suggest that autistic children differ from healthy children in metabolism of mercury, which seems to change with age. PMID:20628443

Majewska, Maria Dorota; Urbanowicz, Ewa; Rok-Bujko, Paulina; Namyslowska, Irena; Mierzejewski, Pawe?

2010-01-01

162

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

PubMed Central

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

2014-01-01

163

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

164

Fish mercury distribution in Massachusetts, USA lakes  

SciTech Connect

The sediment, water, and three species of fish from 24 of Massachusetts' (relatively) least-impacted water bodies were sampled to determine the patterns of variation in edible tissue mercury concentrations and the relationships of these patterns to characteristics of the water, sediment, and water bodies (lake, wetland, and watershed areas). Sampling was apportioned among three different ecological subregions and among lakes of differing trophic status. The authors sought to partition the variance to discover if these broadly defined concepts are suitable predictors of mercury levels in fish. Average muscle mercury concentrations were 0.15 mg/kg wet weight in the bottom-feeding brown bullheads (Ameriurus nebulosus); 0.31 mg/kg in the omnivorous yellow perch (Perca flavescens); and 0.39 mg/kg in the predaceous largemouth bass (Micropterus salmoides). Statistically significant differences in fish mercury concentrations between ecological subregions in Massachusetts, USA, existed only in yellow perch. The productivity level of the lakes (as deduced from Carlson's Trophic Status Index) was not a strong predictor of tissue mercury concentrations in any species. pH was a highly (inversely) correlated environmental variable with yellow perch and brown bullhead tissue mercury. Largemouth bass tissue mercury concentrations were most highly correlated with the weight of the fish (+), lake size (+), and source area sizes (+). Properties of individual lakes appear more important for determining fish tissue mercury concentrations than do small-scale ecoregional differences. Species that show major mercury variation with size or trophic level may not be good choices for use in evaluating the importance of environmental variables.

Rose, J.; Hutcheson, M.S.; West, C.R.; Pancorbo, O.; Hulme, K.; Cooperman, A.; DeCesare, G.; Isaac, R.; Screpetis, A.

1999-07-01

165

Mercury levels in lichens from different host trees around a chlor-alkali plant in New Brunswick, Canada.  

PubMed

Mercury concentrations were determined in the epiphytic lichen Hypogymnia physodes along five transects starting from a chlor-alkali plant located at Dalhousie, New Brunswick, a landfill site and a nearby electricity generating station. Lichen samples were collected from white birch (Betula papyrifera) and spruce (Picea sp.) or balsam fir (Abies balsamea). Average lichen background mercury values were 0.088+/-0.005 microg/g from white birch and 0.148+/-0.046 microg/g from spruce trees, with a detection limit of 0.05 microg/g. The chlor-alkali plant and a power plant were identified, respectively, as a major source and a minor source of elevated mercury levels in lichens. At 125 m north-west of the New Brunswick Power plant, 0.28 microg/g Hg were found in Hypogymnia physodes from spruce trees, while at 250 m west (downwind) of the chlor-alkali plant, 3.66 microg/g of mercury were determined. High values, 0.98 microg/g in lichens from spruce trees and 0.79 microg/g in lichen samples from white birch were also measured at 125 m south of the chlor-alkali plant and decreased exponentially with distance. The sphere of influence of the chlor-alkali plant with respect to mercury deposition was estimated to extend 2.4-3.4 km from the plant. The mercury concentrations in Hypogymnia physodes collected from white birch were significantly lower than the concentrations in the same lichen from spruce trees in areas with elevated levels of mercury, but not in areas with low mercury levels. The magnitude of this difference dropped with distance from the source. PMID:12109479

Sensen, Marion; Richardson, David H S

2002-07-01

166

Expression of hepatic metallothionein messenger RNA in feral and caged fish species correlates with muscle mercury levels.  

PubMed

Metallothioneins (MTs) are low-molecular-weight cytosolic proteins that are induced by cellular stress as well as exposure to various heavy metals including mercury. Excessive residues of mercury have recently been identified in various fish species of the lower Ouachita River system in Arkansas. Fillets of mature largemouth bass (Micropterus salmoides) collected from Woodard Lake, an ox-bow lake of the Ouachita River, possessed muscle residues of mercury ranging from 0.3 to 1.0 ppm (micrograms/g). To assess the usefulness of using MT expression as a biomarker of mercury exposure, livers and fillets were obtained from feral bass of Woodard Lake. Ouachita served as a control site having mercury residues below detection. Analyses using a ribonuclease protection assay with winter flounder MT cDNA revealed that bass had significantly elevated levels of MT mRNA which correlated (r2 = 0.756) with the levels of mercury in muscle fillets. To further explore the water quality of Woodard Lake, 10 juvenile channel catfish were housed in cages and placed where feral collections were made in both sites for 2 weeks. Mercury was not detected in muscle or liver and no significant difference in hepatic MT mRNA was observed. These data demonstrate that MT mRNA expression can be used as a tool to assess exposure to heavy metals and suggest that the elevated levels of mercury in large predatory fish may be due to trophic magnification rather than a single point-source exposure. PMID:7498068

Schlenk, D; Zhang, Y S; Nix, J

1995-08-01

167

Sub-clinical neurobehavioral abnormalities associated with low level of mercury exposure through fish consumption.  

PubMed

In order to assess early neurotoxic effects associated with relatively low levels of mercury absorbed through fish eating, two groups of 22 adult male subjects, habitual consumers of tuna fish, and 22 controls were examined using a cross-sectional field study. The assessment included neurobehavioral tests of vigilance and psychomotor function, hand tremor measurements and serum prolactin assessment. Mercury in urine (U-Hg) and serum prolactin (sPRL) were measured in all exposed subjects and controls, whereas measurements of the organic component of mercury in blood (O-Hg) were available for only 10 exposed and six controls. U-Hg was significant higher among exposed subjects (median 6.5 microg/g of creatinine, range 1.8-21.5) than controls (median 1.5 microg/g of creatinine, range 0.5-5.3). The median values of O-Hg were 41.5 microg/l among the tuna fish eaters and 2.6 microg/l in the control group. Both U-Hg and O-Hg were significantly correlated with the quantity of fish consumed per week. Significant differences in sPRL were found between exposed (12.6 ng/ml) and controls (9.1 ng/ml). Individual sPRL were significantly correlated with both U-Hg and O-Hg levels. The neurobehavioral performance of subjects who consumed tuna fish regularly was significantly worse on color word reaction time, digit symbol reaction time and finger tapping speed (FT). After considering the education level and other covariates, the multiple stepwise regression analysis indicated that O-Hg concentration was most significantly associated with individual performance on these tests, accounting for about 65% of the variance in test scores. PMID:12900074

Carta, Plinio; Flore, Costantino; Alinovi, Rossella; Ibba, Antonio; Tocco, Maria Giuseppina; Aru, Gabriella; Carta, Roberta; Girei, Emanuela; Mutti, Antonio; Lucchini, Roberto; Randaccio, Francesco Sanna

2003-08-01

168

Mercury in seabird feathers: insight on dietary habits and evidence for exposure levels in the western Indian Ocean.  

PubMed

Breast feathers were used to estimate mercury levels in six marine birds nesting in the tropical western Indian Ocean, i.e. Sooty Tern (Sterna fuscata), Brown Noddy (Anous stolidus), Lesser Noddy (Anous tenuirostris), Audubon Shearwater (Puffinus lherminieri bailloni), Barau's Petrel (Pterodroma baraui) and the White-tailed Tropicbird (Phaethon lepturus). Juveniles consistently showed lower plumage mercury than adults. The lowest mean level was noted in juvenile Sooty Terns from the Glorioso Archipelago (0.05 microg g(-1)). The highest levels were obtained for adult Barau's Petrels from Reunion Island (0.96 microg g(-1)). An inter-site analysis of Sooty Tern showed higher mercury levels in birds nesting on Juan de Nova Island. Levels were low in comparison with values reported in the plumage of seabirds worldwide. The potential impacts of the size, the type (fish/cephalopod) and the origin (epi-/meso-pelagic) of prey on mercury intake in birds are discussed. Although the diet composition of individuals within a species appeared to be quite variable, combining results on mercury levels with common knowledge of each species allowed additional information on their dietary and foraging habits to be unraveled. PMID:17659323

Kojadinovic, Jessica; Bustamante, Paco; Churlaud, Carine; Cosson, Richard P; Le Corre, Matthieu

2007-10-01

169

Mercury Concentrations in Plant Tissues as Affected by FGDG Application to Soil  

Technology Transfer Automated Retrieval System (TEKTRAN)

Flue Gas Desulfurization Gypsum (FGDG) is produced by reducing sulfur dioxide emissions from themo-electric coal-fired power plants. The most common practice of FGDG production may trap some of the Mercury (Hg) present in the coal that normally would escape as vapor in the stack gases. Concern for t...

170

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...

171

Long-term changes in fish mercury levels in the historically impacted English-Wabigoon River system (Canada).  

PubMed

The English-Wabigoon River system in Northwestern Ontario, Canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. This study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in Walleye, Northern Pike and Lake Whitefish, three species important for sport and subsistence fishing in this region, using dynamic linear modeling and piecewise regression. For all lakes and species, there is a significant decline (36-94%) in mercury concentrations through time; however, there is evidence that this decline is either slowing down or levelling off. Concentrations in the English-Wabigoon fish are elevated, and may still present a potential health risk to humans consuming fish from this system. Various biotic and abiotic factors are examined as possible explanations to slowing rates of decline in mercury concentrations observed in the mid-1980s. PMID:22785387

Neff, Margaret R; Bhavsar, Satyendra P; Arhonditsis, George B; Fletcher, Rachael; Jackson, Donald A

2012-09-01

172

Optical and Electrical Studies of the Double Acceptor Levels of the Mercury Vacancies in HgCdTe  

NASA Astrophysics Data System (ADS)

Correlations between photoluminescence and temperature-dependent Hall measurements were carried out on unintentionally doped HgCdTe epilayers with cadmium composition of 32.7%. These films were grown by liquid-phase epitaxy and post-annealed under different conditions as follows: a p-type annealing was used to control the mercury vacancy concentration, and an n-type annealing under saturated mercury atmosphere was used to fill the mercury vacancies. Comparison of the results obtained by these two characterization techniques allowed us to identify the two acceptor energy levels of the mercury vacancy. Moreover, the "U-negativity" of the vacancy was evidenced: the ionized state V- is stabilized under the neutral state V0 by the dominance of the Jahn-Teller effect over Coulombic repulsion. Finally, three epilayers with different cadmium compositions were also characterized to complete this study.

Gemain, F.; Robin, I. C.; Brochen, S.; De Vita, M.; Gravrand, O.; Lusson, A.

2012-10-01

173

Influence of waste dump remediation on the levels of mercury in the air.  

PubMed

Mercury concentrations in air were measured at three measuring sites in the vicinity of a waste dump Jakusevec in Zagreb, Croatia over a 4-year period, from the beginning to the end of remediation. Measurements at the beginning of the remediation show that the concentrations of mercury at all three measuring sites were relatively high. Annual mercury mass concentrations in 2001 were between 17 and 445 ng m(-3). Annual mercury averages in 2004 ranged from 8 to 10 ng m(-3). Mercury variations were analysed with regard to the meteorological conditions. The results of this investigation show that in regard to mercury, the remediation was successful. PMID:20401647

Pehnec, Gordana; Sisovi?, Anica; Vadji?, Vladimira; Zuzul, Silva

2010-05-01

174

The mercury burden of the Czech population: An integrated approach  

Microsoft Academic Search

In this paper an integrated approach in assessment of the population exposure from various sources of total mercury (THg) oral intake in the Czech Republic is presented. The information on total mercury levels in diet, drinking water, surface urban soil and body fluids and tissues stem from the Czech national Environmental Health Monitoring System (EHMS) operated since 1994. The THg

Vladimíra Puklová; Andrea Krsková; Milena ?erná; Mája ?ejchanová; Irena ?eh??ková; Ji?í Ruprich; Karel Kratzer; R?žena Kubínová; Magdaléna Zimová

2010-01-01

175

LOCATIONAL DIFFERENCES IN MERCURY AND SELENIUM LEVELS IN 19 SPECIES OF SALTWATER FISH FROM NEW JERSEY  

PubMed Central

Individuals who fish, and their families that ingest self-caught fish, make decisions about where to fish, what type of fish to eat, and the quantity of fish to eat. While federal and state agencies often issue consumption advisories for some fish with high mercury (Hg) concentrations, advisories seldom provide the actual metal levels to the general public. There are few data for most saltwater fish, and even less information on variations in Hg levels in fish within a state or geographical region. The objective of this study was to provide Hg concentrations from 19 species of fish caught in different locations in New Jersey to (1) test the hypothesis that mean metal levels vary geographically, (2) provide this information to individuals who fish these coastal waters, and (3) provide a range of values for risk assessors who deal with saltwater fish exposure in the Northeastern United States. Selenium (Se) was also examined because of its purported moderating effect on the toxicity of Hg. Hg levels showed significant geographical variation for 10 of 14 species that were caught in more than one region of New Jersey, but there were significant locational differences for Se in only 5 of the fish. Mercury levels were significantly lower in fish collected from northern New Jersey (except for ling, Molva molva), compared to other regions. As might be expected, locational differences in Hg levels were greatest for fish species with the highest Hg concentrations (shark, Isurus oxyrinchus; tuna, Thunnus thynnus and T. albacares; striped bass, Morone saxatilis; bluefish, Pomatomus saltatrix). Fishers and their families might reduce their risk from Hg exposure not only by selecting fish generally lower in Hg, but by fishing predominantly in some regions over others, further lowering the potential risk. Health professionals might use these data to advise patients on which fish are safest to consume (in terms of Hg exposure) from particular geographical regions. PMID:21598171

Burger, Joanna; Jeitner, Christian; Gochfeld, Michael

2014-01-01

176

Variability of mercury and selenium levels in clutches of Audouin's gulls (Larus audouinii) breeding at the Chafarinas Islands, Southwest Mediterranean.  

PubMed

We determined mercury and selenium in 43 eggs (eggshell, albumen, and yolk) which belong to different clutch sizes of Audouin's gull from the Chafarinas Islands. The results were compared with those obtained previously with the same species at the Ebro Delta. Both, the intra- and the interclutch sources of variability have been examined. There is an effect of the female on mercury and selenium concentrations in a clutch, which supports the use of eggs as monitoring tools. The distribution pattern of mercury among albumen, yolk and eggshell, the dynamics of this element during the laying process, as well as data concerning egg formation strategies suggest that the mercury in the albumen corresponds mainly to the mercury acquired by the female while feeding in the breeding area. The mercury and selenium levels of the eggs from the Chafarinas Islands were lower than those of the Ebro Delta, which can be due to differences in both the marine contamination and the diet in the two colonies. PMID:10790510

Sanpera, C; Morera, M; Ruiz, X; Jover, L

2000-07-01

177

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 ...

178

Differential Sex, Morphotype and Tissue Accumulation of Mercury in the Crab Carcinus maenas  

Microsoft Academic Search

Carcinus maenas is an invasive species of recognised economical and ecological importance in which mercury accumulation could be a pathway\\u000a for bioamplification through food webs. Little information is available about differential accumulation between crab sexes\\u000a and morphotypes. Taking this in mind, a set of different industrial discharge scenarios were investigated in 96-h laboratory\\u000a experiments for assessing the accumulation of inorganic

Sónia Costa; Ivan Viegas; Eduarda Pereira; Armando C. Duarte; Carlos M. Palmeira; Miguel A. Pardal

179

Influences on Mercury Bioaccumulation Factors for the Savannah River  

SciTech Connect

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118 km reach of the Savannah River demonstrated that species specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat and season related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 106 for largemouth bass, 1.4 x 106 for sunfishes, and 2.5 x 106 for white catfish. Inaccurate and imprecise BAFs can result in unnecessary economic impact or insufficient protection of human health. Determination of representative and precise BAFs for mercury in fish from large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle from the entire area and all habitats to be represented by the TMDL.

Paller, M.H.

2003-05-06

180

Influences on mercury bioaccumulation factors for the Savannah River.  

PubMed

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous methyl mercury samples collected at a number of locations and over several seasons in a 118-km reach of the Savannah River demonstrated that species-specific BAFs varied by factors of three to eight. Factors contributing to BAF variability were location, habitat, and season-related differences in fish muscle tissue mercury levels and seasonal differences in dissolved methyl mercury levels. Overall (all locations, habitats, and seasons) average BAFs were 3.7 x 10(6) for largemouth bass, 1.4 x 10(6) for sunfishes, and 2.5 X 10(6) for white catfish. Determination of representative BAFs for mercury in fish from large rivers necessitates collecting large and approximately equal numbers of fish and aqueous methyl mercury samples over a seasonal cycle from the entire area and all habitats to be represented by the TMDL. PMID:15106676

Paller, M H; Bowers, J A; Littrell, J W; Guanlao, A V

2004-02-01

181

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

182

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

183

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

184

Corn extracts lower tissue arsenic level in rat.  

PubMed

This study was carried out to see whether corn extracts could reduce the accumulation of arsenic in different tissues of rat. Exposure to arsenic (700 microg/rat/day) orally for 15 days led to significant accumulation of arsenic and significant reduction in the concentration of reduced glutathione (GSH) in different tissues. While water, salt, ethanol and alkali extracts of corn were co-administered at a dose of 0.5 mL/rat/day orally by stomach tube during last 8 days, arsenic concentration decreased significantly in all tissues and reduced glutathione (GSH) concentration increased significantly in tissues except heart and skin. Among the extracts, water extract produced maximum reduction of arsenic (69.07% in liver, 64.98% in kidney, 63.47% in lung, 57.55% in heart and 69.30% in skin) and elevation of reduced glutathione level in all tissues (17.03% in liver, 46.73% in lung, 32.67% in heart and 55.38% in skin) except kidney, in which maximum elevation of reduced glutathione was attained by ethanol extract (23.14%). This study suggests that corn extracts might protect rats from accumulation of arsenic in different tissues and oxidative stress, which is reflected by the increasing reduced glutathione concentration in those tissues. PMID:19637542

Chowdhury, Noor Jahan Alam; Misbahuddin, Mir; Rahman, Md Sayedur

2009-04-01

185

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 Resources: EPA General Info on Mercury - http://www.epa.gov/mercury/about.htm FDA Mercury Levels in Seafood.htm World Health Organization Key Facts on Mercury - http://www.who.int/mediacentre/factsheets/fs361

Miami, University of

186

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

187

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

188

Total and organic mercury in liver, kidney and muscle of waterbirds from wetlands of the Caspian Sea, Iran.  

PubMed

We measured and compared total and organic mercury in liver, kidney, and muscle of the Great Cormorant (Phalacrocorax carbo), mallard (Anas platyrhynchos), and coot (Fulica atra) from the Caspian Sea wetlands in Iran. For the Great Cormorant organic mercury in liver, kidney and muscle comprised 82 %, 79 % and 58 % of total mercury. In the mallard same values were 46 %, 54 %, and 64 %. For coot total mercury was: 0.1 ± 0.0, 0.1 ± 0.01, 0.03 ± 0.01 in liver kidney and muscle respectively. We detected no organic mercury. In general older birds that feed on higher trophic levels can accumulate more mercury in their tissues. PMID:22527004

Aazami, J; Esmaili-Saria, A; Bahramifar, N; Savabieasfahani, M

2012-07-01

189

Relationship between the prenatal exposure to low-level of mercury and the size of a newborn's cerebellum.  

PubMed

Exposure to methylmercury at any stage of central nervous system development could induce alterations and result in severe congenital abnormalities. Total mercury level in maternal hair during pregnancy correlates well with blood levels of methylmercury and with total mercury levels in fetal brain. A prospective study has been conducted and a total of 137 childbearing women living at the coastal region with term, normal pregnancies were included and their newborns evaluated by ultrasonography. Mothers and their newborns are divided in two groups according to their hair mercury levels; examined group with high body levels of mercury (? 1 ?g/g) and control group with low body levels of mercury (<1 ?g/g). Neurosonographic examination was conducted to all newborns. Two dimensions of cerebellum in the sagital-medial plane have been measured: maximum height and width starting from the roof of the fourth chamber. Majority of mothers had hair mercury levels lower than 1 ?g/g (N = 107). Mean value was 0.88 ?g/g (SD 1.24), ranging from 0.02 to 8.71 ?g/g. There was no significant difference between the two groups when it comes to the width of cerebellum (Mann-Whitney test: Z = 1471; p = 0.141). However, comparison related to the length of cerebellum shows statistically significant smaller cerebellum in newborns whose mother had hair mercury levels higher than 1 ?g/g (Mann-Whitney test: Z = 2329; p = 0.019). Our results lead to a conclusion that prenatal exposure to, what we consider to be, low-levels of methylmercury does influence fetal brain development detected as decreased size of newborn's cerebellum. From a clinical point of view, a question related to the influence of prenatal low-level methylmercury exposure on fetal neurodevelopment remains open. Our further objectives are to direct the research towards performing detailed neuropshychological tests on children at the age of 18 months. Such tests could indicate the presence of subtle neurological or neuropsychological deficits. PMID:21195558

Cace, I Bilic; Milardovic, A; Prpic, I; Krajina, R; Petrovic, O; Vukelic, P; Spiric, Z; Horvat, M; Mazej, D; Snoj, J

2011-04-01

190

Anthropogenic impacts on mercury concentrations and nitrogen and carbon isotope ratios in fish muscle tissue of the Truckee River watershed, Nevada, USA.  

PubMed

The lower Truckee River originates at Lake Tahoe, California/Nevada (NV), USA and ends in the terminal water body, Pyramid Lake, NV. The river has minimal anthropogenic inputs of contaminants until it encounters the cities of Reno and Sparks, NV, and receives inflows from Steamboat Creek (SBC). SBC originates at Washoe Lake, NV, where there were approximately six mills that used mercury for gold and silver amalgamation in the late 1800s. Since then, mercury has been distributed down the creek to the Truckee River. In addition, SBC receives agricultural and urban nonpoint source pollution, and treated effluent from the Reno-Sparks water reclamation facility. Fish muscle tissue was collected from different species in SBC and the Truckee River and analyzed for mercury and stable isotopes. Nitrogen (delta(15)N) and carbon (delta(13)C) isotopic values in these tissues provide insight as to fish food resources and help to explain their relative Hg concentrations. Mercury concentrations, and delta(15)N and delta(13)C values in fish muscle from the Truckee River, collected below the SBC confluence, were significantly different than that found in fish collected upstream. Mercury concentrations in fish tissue collected below the confluence for all but three fish sampled were significantly greater (0.1 to 0.65 microg/g wet wt.) than that measured in the tissue collected above the confluence (0.02 to 0.1 microg/g). Delta(15)N and delta(13)C isotopic values of fish muscle collected from the river below the confluence were higher and lower, respectively, than that measured in fish collected up river, most likely reflecting wastewater inputs. The impact of SBC inputs on muscle tissue isotope values declined down river whereas the impact due to Hg inputs showed the opposite trend. PMID:16084983

Sexauer Gustin, Mae; Saito, Laurel; Peacock, Mary

2005-07-15

191

Bioaccumulation of mercury in pelagic fishes in NW Gulf of Mexico  

E-print Network

Total mercury (Hg) levels were determined in the tissues of ten taxa of pelagic fishes, with a special emphasis on apex predators (large vertebrates). Highest Hg levels were observed in blue marlin (Makaira nigricans), carcharhinid sharks (Genus...

Cai, Yan

2006-08-16

192

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

193

Maternal and umbilical cord blood levels of mercury, lead, cadmium, and essential trace elements in Arctic Canada  

SciTech Connect

Maternal and umbilical cord blood levels of mercury (Hg), lead (Pb), cadmium (Cd), and the trace elements copper (Cu), zinc (Zn), and selenium (Se) are reported for Inuit, Dene/Metis, Caucasian, and Other nonaboriginal participants from Arctic Canada. This is the first human tissue monitoring program covering the entire Northwest Territories and Nunavut for multiple contaminants and establishes a baseline upon which future comparisons can be made. Results for chlorinated organic pesticides and PCBs for these participants have been reported elsewhere. Between May 1994 and June 1999, 523 women volunteered to participate by giving their written informed consent, resulting in the collection of 386 maternal blood samples, 407 cord samples, and 351 cord:maternal paired samples. Geometric mean (GM) maternal total mercury (THg) concentrations ranged from 0.87{mu}g/L (SD=1.95) in the Caucasian group of participants (n=134) to 3.51{mu}g/L (SD=8.30) in the Inuit group (n=146). The GM of the Inuit group was 2.6-fold higher than that of the Dene/Metis group (1.35{mu}g/L, SD=1.60, n=92) and significantly higher than those of all other groups (P<0.0001). Of Inuit women participants, 3% (n=4) were within Health Canada's level of concern range (20-99{mu}g/L) for methylmercury (MeHg) exposure. Of Inuit and Dene/Metis cord samples, 56% (n=95) and 5% (n=4), respectively, exceeded 5.8{mu}g/L MeHg, the revised US Environmental Protection Agency lower benchmark dose. GM maternal Pb was significantly higher in Dene/Metis (30.9{mu}g/L or 3.1{mu}g/dL; SD=29.1{mu}g/L) and Inuit (31.6{mu}g/L, SD=38.3) participants compared with the Caucasian group (20.6{mu}g/L, SD=17.9) (P<0.0001). Half of all participants were smokers. GM blood Cd in moderate smokers (1-8 cigarettes/day) and in heavy smokers (>8 cigarettes/day) was 7.4-fold higher and 12.5-fold higher, respectively, than in nonsmokers. The high percentage of smokers among Inuit (77%) and Dene/Metis (48%) participants highlights the need for ongoing public health action directed at tobacco prevention, reduction, and cessation for women of reproductive age. Pb and THg were detected in more than 95% of all cord blood samples, with GMs of 21 {mu}g/L and 2.7{mu}g/L, respectively, and Cd was detected in 26% of all cord samples, with a GM of 0.08{mu}g/L. Cord:maternal ratios from paired samples ranged from 0.44 to 4.5 for THg, from 0.5 to 10.3 for MeHg, and 0.1 to 9.0 for Pb. On average, levels of THg, MeHg, and Zn were significantly higher in cord blood than in maternal blood (P<0.0001), whereas maternal Cd, Pb, Se, and Cu levels were significantly higher than those in cord blood (P<0.0001). There was no significant relationship between methylmercury and selenium for the range of MeHg exposures in this study. Ongoing monitoring of populations at risk and traditional food species, as well as continued international efforts to reduce anthropogenic sources of mercury, are recommended.

Butler Walker, Jody [J. Butler Walker and Associates, 15 Balsam Crescent, Whitehorse, YT Y1A 4V6 (Canada)]. E-mail: jody@butlerwalker.ca; Houseman, Jan [Formerly Inuvik Regional Human Contaminants Monitoring Program coordinators, Inuvik, NT (Canada); Seddon, Laura [Formerly Mackenzie and Kitikmeot Maternal and Cord Blood Monitoring Program coordinators, Yellowknife, NT (Canada); McMullen, Ed [J. Butler Walker and Associates, Whitehorse, YT (Canada); Tofflemire, Karen [Formerly Inuvik Regional Human Contaminants Monitoring Program coordinators, Inuvik, NT (Canada); Mills, Carole [Formerly Mackenzie and Kitikmeot Maternal and Cord Blood Monitoring Program coordinators, Yellowknife, NT (Canada); Corriveau, Andre [Government of the Northwest Territories (GNWT), Department of Health and Social Services, Yellowknife, NT (Canada); Weber, Jean-Philippe [Laboratoire de Toxicologie, Institut national de sante publique du Quebec, Sainte-Foy, QC (Canada); LeBlanc, Alain [Laboratoire de Toxicologie, Institut national de sante publique du Quebec, Sainte-Foy, QC (Canada); Walker, Mike [Health Canada, Safe Environments Programme, Ottawa, ON (Canada); Donaldson, Shawn G. [Health Canada, Safe Environments Programme, Ottawa, ON (Canada); Van Oostdam, Jay [Health Canada, Safe Environments Programme, Ottawa, ON (Canada)

2006-03-15

194

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

195

Mercury bioacumulation in four tissues of Podocnemis erythrocephala (Podocnemididae: Testudines) as a function of water parameters.  

PubMed

A number of environmental factors influence the dynamics of Hg in aquatic ecosystems, yet few studies have examined these factors for turtles, especially from South America. Red-headed river turtle (Podocnemis erythrocephala) is easy to capture in the black waters of Rio Negro, making it the turtle species that is consumed most often by people of the region. In this study, environmental factors and turtle size were investigated to determine their influence on the Hg concentration in blood, muscle, liver and carapace of the red-headed river turtle. Factors investigated included turtle length, pH, dissolved organic carbon and availability of potential methylation sites (floodplain forests and hydromorphic soils). The study was conducted in the Rio Negro basin, where we collected water and turtle blood, muscle, liver and carapace samples from 12 tributaries for chemical analysis. Through radar imagery and existing soil maps with GIS, the percentage of alluvial floodplains and hydromorphic soils (potential methylation sites) was estimated for each drainage basin at sampling points. The mean Hg concentration in blood of P. erythrocephala was 1.64 ng g(-1) (SD=1.36), muscle 33 ng g(-1) (SD=11), liver 470 ng g(-1) (SD=313) and carapace 68 ng g(-1) (SD=32). Sex or length did not influence the Hg concentration in P. erythrocephala blood, muscle and liver, but Hg increased in carapace tissue when length size increased (ANCOVA p=0.007). In the multiple regression analysis, none of the environmental factors studied had a significant relation with blood, muscle, liver and carapace. P. erythrocephala moves among habitats and in the open and interconnected aquatic systems of the Amazon basin, characterized by high levels of limnological variability, a good bioindicator of Hg concentration needs to be relatively sedentary to represent a specific habitat. However, the levels of Hg in liver were sufficient to pose a potential risk to humans that consume them, suggesting the usefulness of P. erythrocephala as a bioindicator. PMID:19022475

Schneider, Larissa; Belger, Lauren; Burger, Joanna; Vogt, Richard C

2009-01-15

196

Total mercury, cadmium and lead levels in main export fish of Sri Lanka.  

PubMed

Total mercury (Hg), cadmium (Cd) and lead (Pb) levels were determined in the muscle of four commercialised exported fish species Thunnus albacares (yellowfin tuna), Xiphias gladius (swordfish), Makaira indica (black marlin) and Lutjanus sp (red snapper) collected from the Indian Ocean, Sri Lanka, during July 2009-March 2010 and measured by atomic absorption spectrophotometry. Results show that swordfish (n = 176) contained the highest total Hg (0.90 ± 0.51 mg/kg) and Cd (0.09 ± 0.13 mg/kg) levels, whereas yellowfin tuna (n = 140) contained the highest Pb levels (0.11 ± 0.16 mg/kg). The lowest total Hg (0.16 ± 0.11 mg/kg), Cd (0.01 ± 0.01 mg/kg) and Pb (0.04 ± 0.04 mg/kg) levels were found in red snapper (n = 28). Black marlin (n = 24) contained moderate levels of total Hg (0.49 ± 0.37), Cd (0.02 ± 0.02) and Pb (0.05 ± 0.05). Even though there are some concerns during certain months of the year, this study demonstrates the safety of main export fish varieties in terms of total Hg, Cd and Pb. PMID:25070289

Jinadasa, B K K K; Edirisinghe, E M R K B; Wickramasinghe, I

2014-12-01

197

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

198

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

199

Chronic low-level mercury exposure, BDNF polymorphism, and associations with cognitive and motor function.  

PubMed

Potential cognitive and motor effects from exposure to elemental mercury (Hg(0)) were examined in the presence and absence of a polymorphism (Val66Met) in brain-derived neurotrophic factor (BDNF). A group of 194 male dentists (DDs) and 233 female dental assistants (DAs) were occupationally exposed to mercury and had no history of kidney or nervous system disorders. Acute exposure was measured using spot urinary Hg (HgU) concentrations (average 3.32 and 1.98 microg/l, respectively) and indices of chronic occupational exposure (26.3 and 14.9 years, respectively, weighted for historical exposures). The BDNF status was 68% and 66% wild type, 26% and 30% single substitution, and 5% and 4% full mutation for DDs and DAs, respectively. DDs and DAs were evaluated separately. Regression analyses controlled for age, premorbid intelligence, alcohol consumption, and education. Statistically significant adverse associations with HgU (p<.05) were found for nine measures among DDs (Digit Span (Forward), Digit and Spatial Span(Backward), Visual Reproduction, Finger Tapping(Dominant, Alternate, and Alternate Partialed), Hand Steadiness, and Tracking), and eight measures among DAs (Digit Span(Forward), Visual Reproduction, Pattern Discrimination(Rate), Symbol Digit(Rate), Trailmaking B, Finger Tapping(Dominant and Alternate Partialed), and Hand Steadiness). The BDNF status was associated with four measures in DDs and three measures in DAs. Joint effects were found for Finger Tapping(Alternate and Alternate Partialed) in DDs and Hand Steadiness and Trailmaking B in DAs. Joint effects were additive in all cases. Performance on verbal intelligence and reaction time were not associated with either HgU or BDNF status. A test of threshold effect for the association of Hand Steadiness with HgU demonstrated no lower boundary in both DDs and DAs. No associations were observed with estimates of chronic mercury exposure. Our findings are applicable to exposure levels of the general population and identify a potentially vulnerable group with a BDNF polymorphism. PMID:16301096

Echeverria, Diana; Woods, James S; Heyer, Nicholas J; Rohlman, Dianne S; Farin, Federico M; Bittner, Alvah C; Li, Tingting; Garabedian, Claire

2005-01-01

200

Fish Consumption, Low-Level Mercury, Lipids, and Inflammatory Markers in Children  

PubMed Central

There is considerable evidence that consuming fish has numerous health benefits, including a reduced risk of cardiovascular disease. However, fish is also the primary source of human exposure to mercury (Hg). In a cross-sectional study of 9–11 year old children (N = 100), we measured fish consumption, blood lipids, total blood Hg, diurnal salivary cortisol (4 samples collected throughout the day), and performed a proteomic analysis of serum proteins using spectral count shotgun proteomics. Children that consumed fish had a significantly more atheroprotective lipid profile but higher levels of blood Hg relative to children that did not consume fish. Although the levels of blood Hg were very low in these children (M = 0.77 ?g/L; all but 1 participant had levels below 3.27 ?g/L), increasing blood Hg was significantly associated with blunted diurnal cortisol levels. Blood Hg was also significantly associated with acute-phase proteins suggesting systemic inflammation, and several of these proteins were found to significantly reduce the association between Hg and diminished cortisol when included in the model. This study of a pediatric population is the first to document an association between blood Hg, systemic inflammation, and endocrine disruption in humans, in a pediatric sample. Without a better understanding of the long-term consequences of an atheroprotective lipid profile relative to blunted diurnal cortisol and systemic inflammation, a determination of the risk-benefit ratio for fish consumption by children is not possible. PMID:22030286

Gump, Brooks B.; MacKenzie, James A.; Dumas, Amy K.; Palmer, Christopher D.; Parsons, Patrick J.; Segu, Zaneer M.; Mechref, Yehia S.; Bendinskas, Kestutis

2011-01-01

201

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, Michael A.; Kajdacsy-Balla, A.

2011-01-01

202

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

E-print Network

mesopelagic zone Mercury is a trace element distributed throughout the earth's atmosphere, biosphere cycles, resulting in retention of trace amounts of this metal in plants and animals. Inter- and intra of higher-mercury containing deeper-water prey organisms in the diets of the deeper- ranging predators, X

Hawai'i at Manoa, University of

203

The influence of fish length on tissue mercury dynamics: implications for natural resource management and human health risk.  

PubMed

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

2013-02-01

204

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

205

Factors Affecting Mercury and Selenium Levels-in New Jersey Flatfish: Low Risk to Human Consumers  

PubMed Central

Some fish contain high levels of mercury (Hg), which could pose a risk to fish eaters themselves or their children. In making decisions about fish consumption, people must decide whether to eat fish, how much to eat, what species to eat, and what size fish to eat, as well as suitable (or unsuitable) locations, among other factors. Yet to make sound decisions, people need to know the levels of Hg in fish as a function of species, size, and location of capture. Levels of Hg and selenium (Se) were examined in three species of flatfish (fluke or summer flounder [Paralichthys dentatus], winter flounder [Pseudopleuronectes americanus], and windowpane [Scophthalmus aquosus]) from New Jersey as a function of species, fish size, season, and location. Flatfish were postulated to have low levels of Hg because they are low on the food chain and are bottom feeders, and data were generated to provide individuals with information on a species that might be safe to eat regularly. Although there were interspecific differences in Hg levels in the 3 species, total Hg levels averaged 0.18, 0.14, and 0.06 ppm (?g/g, wet weigh) in windowpane, fluke, and winter flounder, and selenium levels averaged 0.36, 0.35, and 0.25 ppm, respectively. For windowpane, 15% had Hg levels above 0.3 ppm, but no individual fish had Hg levels over 0.5 ppm. There were no significant seasonal differences in Hg levels, although Se was significantly higher in fluke in summer compared to spring. There were few geographical differences among New Jersey locations. Correlations between Hg and Se levels were low. Data, based on 464 fish samples, indicate that Hg levels are below various advisory levels and pose little risk to typical New Jersey fish consumers. A 70-kg person eating 1 meal (8 oz or 227 g) per week would not exceed the U.S. Environmental Protection Agency reference dose of 0.1 ?g/kg body weight/d of methylmercury (MeHg). However, high-end fish eaters consuming several such meals per week may exceed recommended levels. PMID:19557613

Burger, Joanna; Jeitner, Christian; Donio, Mark; Shukla, Sheila; Gochfeld, Michael

2014-01-01

206

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

207

Superpredation increases mercury levels in a generalist top predator, the eagle owl.  

PubMed

Superpredation can increase the length of the food chain and potentially lead to mercury (Hg) bioaccumulation in top predators. We analysed the relationship of Hg concentrations in eagle owls Bubo bubo to diet composition and the percentage of mesopredators in the diet. Hg levels were measured in the adult feathers of eagle owls from 33 owl territories in the south-western Iberian Peninsula, and in three trophic levels of their prey: primary consumers, secondary consumers and mesopredators. In addition, we studied 6,181 prey in the eagle owl diet. Hg concentrations increased along the food chain, but the concentrations in eagle owls showed considerable variation. The Hg concentration in eagle owls increased when the percentage of mesopredators in the diet increased and the percentage of primary consumers decreased. Superpredation is often related to food stress, and the associated increase in accumulation of Hg may cause additional negative effects on vertebrate top predators. Hg levels in these eagle owl populations are relatively low, but future monitoring is recommended. PMID:21298339

Lourenço, Rui; Tavares, Paula C; del Mar Delgado, Maria; Rabaça, João E; Penteriani, Vincenzo

2011-06-01

208

Mercury Concentrations in Fish from Lake Mead, USA, Related to Fish Size, Condition, Trophic Level, Location, and Consumption Risk  

Microsoft Academic Search

Total mercury (Hg) concentrations were determined in the skeletal muscle of 339 fish collected during the fall of 1998 and\\u000a spring of 1999 from Lake Mead, USA, the nation's largest human-made reservoir. Five species of fish representing a range of\\u000a trophic levels and the lake's principal game fishes were studied. Hg generally increased with trophic level and fish size.\\u000a Median

J. V. Cizdziel; T. A. Hinners; J. E. Pollard; E. M. Heithmar; C. L. Cross

2002-01-01

209

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

210

Landscape-level patterns of mercury contamination of fish in North Texas, USA.  

PubMed

Mercury (Hg) is a toxic metal that is found in aquatic food webs and is hazardous to humans. An emerging conceptual model predicts that the areas of the landscape that have the potential to contain food webs with elevated concentrations of Hg are those that receive high amounts of Hg and sulfate deposition and have high coverage of forests and wetlands and low coverage of agriculture. The objective of the present study was to test this conceptual model using concentrations of Hg in largemouth bass (Micropterus salmoides) from 145 reservoirs in four ecoregions of North Texas. The highest level of Hg contamination in fish was in the South Central Plains, the ecoregion that receives the highest levels of Hg and sulfate deposition and contains extensive forest and wetland habitat and little agriculture. The present study has important implications for other areas of the United States, because the South Central Plains extend into parts of Oklahoma, Louisiana, and Arkansas, covering a total area of 152,132 km(2) of the southern United States. PMID:21647946

Drenner, Ray W; Chumchal, Matthew M; Wente, Stephen P; McGuire, Mandy; Drenner, S Matthew

2011-09-01

211

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

212

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

213

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...

214

An XAFS Investigation of Mercury and Selenium in Beluga Whale Tissues  

Microsoft Academic Search

High dietary methylmercury (MeHg) exposures are often associated with increased accumulation of selenium (Se), particularly in tissues with rapid rates of selenocysteine synthesis. Conversely, increased dietary Se intakes result in increased accumulation of Hg, possibly because of mutual sequestration in insoluble HgSe complexes. In the current study, results from Hg X-ray absorption fine structure (XAFS) spectroscopy of lyophilized liver and

Frank E. Huggins; Stephen A. Raverty; Ole S. Nielsen; Nicholas E. Sharp; J. David Robertson; Nicholas V. C. Ralston

2009-01-01

215

Hydrolysis of carbohydrates in roach ( Rutilus rutilus (L.)) at different levels of mercury accumulation  

Microsoft Academic Search

It has been shown that chronic exposure to dietary mercury results in the intensive accumulation of this metal in roach yearlings.\\u000a The concentrations of accumulated mercury in their organisms were proportional to the amount of metal added to water of experimental\\u000a tanks. Increased Hg content in the organisms (0.05–0.16 mg\\/kg) of developing juvenile roaches decreases the activity of digestive\\u000a carbohydrases

I. L. Golovanova; V. T. Komov; V. A. Gremyatchikh

2008-01-01

216

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

PubMed

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(2), HgCl(2), NaAsO(2) and MnCl(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(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(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(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(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(2) enhanced AMPK activation in a dose-dependent manner in the liver, skeletal muscle and WAT; HgCl(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. PMID:22019852

Kawakami, Takashige; Hanao, Norihide; Nishiyama, Kaori; Kadota, Yoshito; Inoue, Masahisa; Sato, Masao; Suzuki, Shinya

2012-01-01

217

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...

218

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

219

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

220

IMPACT OF ELIMINATING MERCURY REMOVAL PRETREATMENT ON THE PERFORMANCE OF A HIGH LEVEL RADIOACTIVE WASTE MELTER OFFGAS SYSTEM  

SciTech Connect

The Defense Waste Processing Facility at the Savannah River Site processes high-level radioactive waste from the processing of nuclear materials that contains dissolved and precipitated metals and radionuclides. Vitrification of this waste into borosilicate glass for ultimate disposal at a geologic repository involves chemically modifying the waste to make it compatible with the glass melter system. Pretreatment steps include removal of excess aluminum by dissolution and washing, and processing with formic and nitric acids to: (1) adjust the reduction-oxidation (redox) potential in the glass melter to reduce radionuclide volatility and improve melt rate; (2) adjust feed rheology; and (3) reduce by steam stripping the amount of mercury that must be processed in the melter. Elimination of formic acid pretreatment has been proposed to eliminate the production of hydrogen in the pretreatment systems; alternative reductants would be used to control redox. However, elimination of formic acid would result in significantly more mercury in the melter feed; the current specification is no more than 0.45 wt%, while the maximum expected prior to pretreatment is about 2.5 wt%. An engineering study has been undertaken to estimate the effects of eliminating mercury removal on the melter offgas system performance. A homogeneous gas-phase oxidation model and an aqueous phase model were developed to study the speciation of mercury in the DWPF melter offgas system. The model was calibrated against available experimental data and then applied to DWPF conditions. The gas-phase model predicted the Hg{sub 2}{sup 2-}/Hg{sup 2+} ratio accurately, but some un-oxidized Hg{sup 0} remained. The aqueous model, with the addition of less than 1 mM Cl{sub 2} showed that this remaining Hg{sup 0} would be oxidized such that the final Hg{sub 2}{sup 2+}/Hg{sup 2+} ratios matched the experimental data. The results of applying the model to DWPF show that due to excessive shortage of chloride, only 6% of the mercury fed is expected to be chlorinated, mostly as Hg{sub 2}Cl{sub 2}, while the remaining mercury would exist either as elemental mercury (90%) or HgO (4%).

Zamecnik, J; Alexander Choi, A

2009-03-17

221

Regional differences in mercury levels in aquatic ecosystems: A discussion of possible causal factors with implications for the Tennessee river system and the Northern Hemisphere  

NASA Astrophysics Data System (ADS)

Concern about mercury pollution from atmospheric deposition has risen markedly in the last decade because of high levels of mercury in freshwater fish from relatively pristine waters. Whereas high concentrations have been found principally in Canada, the northern United States, and Scandinavia, they have also recently been observed throughout much of Florida. Recent surveys of the Tennessee River system, however, have found no locations where fish levels exceed EPA guidelines for fish consumption. This paper evaluates a number of factors that may cause certain regions in the northern hemisphere to experience unacceptable fish mercury levels while other regions do not. Relevant regional differences include: (1) Waters of the Tennessee River system are generally nonacidic (pH>6) and well buffered, whereas 16%, 22%, and 40% of the lakes in upper Midwest, Northeast, and Florida, respectively, have acid-neutralizing capacities below 50 µeq/liter. Acidity correlates highly with fish mercury levels in a number of lake surveys, and experimental manipulations of acidity have significantly raised fish mercury levels. (2) The ratio of land area to water surface area in the Tennessee Valley averages about 30, whereas it is 15 in the upper Midwest and 6 in Florida. Low ratios allow mercury in precipitation to be directly deposited to aquatic bodies, without an opportunity for the mercury to be sequestered by terrestrial ecosystems. (3) Stream organic matter concentrations in Florida, the upper Midwest, and Sweden are 2 10 times those in the Tennessee Valley. Mercury binds strongly to organic matter, and organic matter transport in runoff is a major pathway by which mercury enters aquatic ecosystems.

Joslin, J. Devereux

1994-07-01

222

Mercury contamination in turtles and implications for human health.  

PubMed

Mercury contamination threatens many ecosystems worldwide. Methylmercury bioaccumulates at each trophic level, and biomagnifies within individuals over time. Long-lived turtles often occupy high trophic positions and are likely to accumulate mercury in contaminated habitats. Millions of turtles worldwide are sold in Asia for human consumption, and consumers may be at risk if turtles contain high levels of mercury. The authors dissected 71 turtles from 14 food trade species and analyzed their tissues (liver, kidneys, muscle, claws, and scutes) for total mercury content. Mercury was generally highest in carnivores, and lowest in herbivores. Liver and scutes had the highest concentrations. The authors compared mercury concentrations with consumption limits developed by the U.S. Environmental Protection Agency and Food and Drug Administration to evaluate mercury in fish tissue. Several samples exceeded the recommended 1,900 parts per billion (ppb) consumption threshold, indicating that consumers who eat certain turtle species frequently may be at risk for mercury-related health problems. PMID:20556939

Green, Aaliyah D; Buhlmann, Kurt A; Hagen, Cris; Romanek, Christopher; Gibbons, J Whitfield

2010-06-01

223

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

224

Mercury in herons, egrets, and their foods  

Microsoft Academic Search

Mercury concentration levels were measured in herons and egrets and their foods collected in the southwestern Lake Erie region. Primary wing feathers, breast muscle, liver, and brain tissues were analyzed from 432 great blue herons (Ardea herodias), 44 black-crowned night herons (Nycticorax nycticorax), and 43 great egrets (Casmerodius albus). Concentrations were higher in island nesting birds than birds collected at

R. D. Hoffman; R. D. Curnow

1979-01-01

225

Removal of mercury from soil with earthworms  

SciTech Connect

Earthworms can live in soils containing high quantities of mercury, lead, and zinc. The worms (Lumbricus terrestris) concentrate these heavy metals in their tissues. The use of these worms to reduce the quantities of mercury and other heavy metals in soils may be practical. In July, 1993, a preliminary study was made using earthworms and soils with differing amounts of mercury, The quantities were 0.0 grams, 0.5 grams, and 1.0 grams of mercury as mercuric chloride. Earthworms were placed into these soils for two or more weeks, then harvested. The worms were rinsed with deionized water, then dissolved in nitric acid. Each sample was prepared for analysis with the addition of HNO{sub 3}, H{sub 2}SO{sub 4}, potassium permanganate, and hydrozylamine hydrochloride. A Jerome Instrument gold foil analyzer was used to determine levels of mercury after volatilizing the sample with stannous chloride. Worms exposed to contaminated soils remove 50 to 1,400 times as much mercury as do worms in control soils. In a hypothetical case, a site contaminated with one pound of mercury, 1,000 to 45,000 worms would be required to reduce mercury levels to background levels in the soil (about 250 ppb). After harvesting worms in contaminated soil they could be dried (90% of their weight is water), and the mercury regained by chemical processes. Soil conducive to earthworm survival is required. This includes a well aerated loamy soil, proper pH (7.0), and periodic watering and feeding. There are several methods of harvesting worms, including flooding and electricity. Large numbers of worms can be obtained from commercial growers.

Dorfman, D. [Monmouth Coll., West Long Branch, NJ (United States)

1994-12-31

226

Plant Uptake of Mercury from Contaminated Soil, Oxford, Alabama  

NASA Astrophysics Data System (ADS)

Mercury contamination in the Oxford, Alabama, area is well documented in soil tests in the Snow Creek watershed. In this investigation, mercury levels in soils as well as local plant species were examined. The objectives of the study were first determining the amount of mercury in the soil and then to determine to what degree this mercury is taken in by plant tissue from specimens at each survey site. Variation in accumulation within the individual plant species (leaves, stems) was also examined. Protocols developed for this study were used to achieve both objectives and also to ascertain if a particular plant species hyper accumulates this toxin at levels that would make it useful in bioremediation of mercury contamination in the area.

Steffy, D. A.; Nichols, A. C.

2005-12-01

227

Relationship between Blood Mercury Level and Risk of Cardiovascular Diseases: Results from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV) 2008–2009  

PubMed Central

Limited epidemiologic data is available regarding the cardiovascular effects of mercury exposure. The purpose of this study was to determine the relationship between mercury exposure from fish consumption and cardiovascular disease in a nationally representative sample of Korean adults using the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV 2008~2009). Survey logistic regression models accounting for the complex sampling were used to estimate the odds ratios (OR) adjusted for fish consumption frequency, age, education, individual annual income, household annual income, body mass index (BMI), waist circumference (WC), alcohol consumption status, and smoking status. The mean blood mercury level in the population was 5.44 ?g/L. Trends toward increased blood mercury levels were seen for increased education level (P=0.0011), BMI (P<0.0001), WC (P<0.0001), and fish (i.e., anchovy) consumption frequency (P=0.0007). The unadjusted OR for hypertension in the highest blood mercury quartile was 1.450 [95% confidential interval (CI): 1.106~1.901] times higher than that of the lowest quartile. The fish consumption-adjusted OR for hypertension in the highest blood mercury quartile was 1.550 (95% CI: 1.131~2.123) times higher than that of the lowest quartile, and the OR for myocardial infarction or angina in the highest blood mercury quartile was 3.334 (95% CI: 1.338~8.308) times higher than that of the lowest quartile. No associations were observed between blood mercury levels and stroke. These findings suggest that mercury in the blood may be associated with an increased risk of hypertension and myocardial infarction or angina in the general Korean population. PMID:25580399

Kim, Young-Nam; Kim, Young A; Yang, Ae-Ri; Lee, Bog-Hieu

2014-01-01

228

Effects of coadministered sodium selenite on short-term distribution on methyl mercury in the rat  

SciTech Connect

Adult male Sprague-Dawley rats received iv injections of 1 ..mu..mole of methyl mercury/kg alone or coadministered with 5 ..mu..mole of sodium selenite/kg. Tissue concentrations of methyl mercury were determined at 5, 20, and 60 min after treatment. Selenite treatment produced a significant increase in cerebral methyl mercury concentrations and a significant decrease in kidney methyl mercury concentrations at all time points. The concentration of methyl mercury in liver was significantly increased by selenite coadministration at 5 and 20 min but at 60 min after injection the concentration was not significantly different from that found in rats receiving methyl mercury alone. Selenite treatment also significantly lowered blood methyl mercury concentrations at all time points. This decrease was associated with a significant decrease in the concentration of methyl mercury in erythrocytes at 5, 20, and 60 min. Plasma methyl mercury levels at 5 min postinjection were slightly higher in selenite-treated rats but were significantly lower in treated animals at 20 and 60 min. Treatment of rats with selenite did not specifically alter the extent of methyl mercury binding to glutathione in the 108,000 g supernatant of cerebrum of in erythrocyte hemolysates. In rats receiving either methyl mercury alone or with selenite, low-molecular-weight methyl mercury complexes could not be detected in plasma 5 min after iv injection.

Thomas, D.J.; Smith, J.C.

1984-08-01

229

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

230

Serum vitamin D levels may not reflect tissue-level vitamin D in sarcoidosis.  

PubMed

Hypercalcemia in sarcoidosis is due to three mechanistic reasons: (1) systemic conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D by the enzyme 1-? hydroxylase produced by activated monocyte/macrophage system, (2) production of parathormone-related peptide (PTHrP) by the sarcoid granuloma, (3) tissue-level conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D by 1-?hydroxylase produced by local monocyte/macrophage system in the sarcoid granuloma. We report two cases of one proposed mechanism of hypercalcaemia in sarcoidosis (mechanism 3). Both individuals presented with sarcoidosis and 25-hydroxyvitamin D deficiency and developed symptomatic hypercalcaemia with vitamin D replacement. Given their low serum parathormone and parathormone-related peptide levels, low serum 25-hydroxy vitamin D and normal serum 1,25-dihydroxyvitamin D, the systemic 25-hydroxy vitamin D deficiency may not have reflected an increased activity of vitamin D at the local granulomatous tissue level. PMID:24663253

Berlin, Jill Lauren; Shantha, Ghanshyam Palamaner Subash; Yeager, Henry; Thomas-Hemak, Linda

2014-01-01

231

Total Blood Mercury Levels and Depression among Adults in the United States: National Health and Nutrition Examination Survey 2005–2008  

PubMed Central

Background Mercury is a neurotoxicant linked with psychiatric symptoms at high levels of exposure. However, it is unclear whether an association is present at the low exposure levels in the US adult population. Materials and Methods Cross-sectional associations of total blood mercury and depression were assessed in 6,911 adults age ?20 in the National Health and Nutrition Examination Survey (NHANES), 2005–2008. The Patient Health Questionnaire-9 was used to assess depression (high likelihood of a depressive spectrum disorder diagnosis; score 5–27). Results Unadjusted survey weighted logistic regression suggested that higher total blood mercury was associated with lower odds of depression (Odds Ratio ?=?0.49, 95% Confidence Interval: 0.36–0.65, comparing the highest and lowest mercury quintiles). This association largely disappeared after adjustment for sociodemographic variables (income-poverty ratio, education, marital status). However, in age-stratified analyses, this inverse relationship remained in older adults (age ?40) even after adjustment for sociodemographic variables. Simulation analyses adjusting for expected confounding effects of fish intake suggested that the inverse relationship among older adults may be plausibly attributed to residual confounding (Odds Ratio ?=?0.75, 95% Confidence Interval: 0.50–1.12, comparing the highest and lowest mercury quintiles). Conclusions Higher total blood mercury was not associated with increased odds of depression. The lower odds of depression in older adults with higher total blood mercury may be due to residual confounding. PMID:24244482

Ng, Tsz Hin H.; Mossey, Jana M.; Lee, Brian K.

2013-01-01

232

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

233

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...

234

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

235

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

236

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.

WGBH Educational Foundation

2010-12-23

237

Elevated tissue factor and tissue factor pathway inhibitor circulating levels in ischaemic heart disease patients.  

PubMed

Several studies have shown that thrombosis and inflammation play an important role in the pathogenesis of Ischaemic Heart Disease (IHD). In particular, Tissue Factor (TF) is responsible for the thrombogenicity of the atherosclerotic plaque and plays a key role in triggering thrombin generation. The aim of this study was to evaluate the TF/Tissue Factor Pathway Inhibitor (TFPI) system in patients with IHD. We have studied 55 patients with IHD and not on heparin [18 with unstable angina (UA), 24 with effort angina (EA) and 13 with previous myocardial infarction (MI)] and 48 sex- and age-matched healthy volunteers, by measuring plasma levels of TF, TFPI, Prothrombin Fragment 1-2 (F1+2), and Thrombin Antithrombin Complexes (TAT). TF plasma levels in IHD patients (median 215.4 pg/ml; range 72.6 to 834.3 pg/ml) were significantly (p<0.001) higher than those found in control subjects (median 142.5 pg/ml; range 28.0-255.3 pg/ml). Similarly, TFPI plasma levels in IHD patients were significantly higher (median 129.0 ng/ml; range 30.3-316.8 ng/ml; p<0.001) than those found in control subjects (median 60.4 ng/ml; range 20.8-151.3 ng/ml). UA patients showed higher amounts of TF and TFPI plasma levels (TF median 255.6 pg/ml; range 148.8-834.3 pg/ml; TFPI median 137.7 ng/ml; range 38.3-316.8 ng/ml) than patients with EA (TF median 182.0 pg/ml; range 72.6-380.0 pg/ml; TFPI median 115.2 ng/ml; range 47.0-196.8 ng/ml) and MI (TF median 213.9 pg/ml; range 125.0 to 341.9 pg/ml; TFPI median 130.5 ng/ml; range 94.0-207.8 ng/ml). Similar levels of TF and TFPI were found in patients with mono- or bivasal coronary lesions. A positive correlation was observed between TF and TFPI plasma levels (r = 0.57, p<0.001). Excess thrombin formation in patients with IHD was documented by TAT (median 5.2 microg/l; range 1.7-21.0 microg/l) and F1+2 levels (median 1.4 nmol/l; range 0.6 to 6.2 nmol/l) both significantly higher (p<0.001) than those found in control subjects (TAT median 2.3 microg/l; range 1.4-4.2 microg/l; F1+2 median 0.7 nmol/l; range 0.3-1.3 nmol/l). As in other conditions associated with cell-mediated clotting activation (cancer and DIC), also in IHD high levels of circulating TF are present. Endothelial cells and monocytes are the possible common source of TF and TFPI. The blood clotting activation observed in these patients may be related to elevated TF circulating levels not sufficiently inhibited by the elevated TFPI plasma levels present. PMID:9531029

Falciani, M; Gori, A M; Fedi, S; Chiarugi, L; Simonetti, I; Dabizzi, R P; Prisco, D; Pepe, G; Abbate, R; Gensini, G F; Neri Serneri, G G

1998-03-01

238

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

239

Mercury in various tissues of three mustelid species and other trace metals in liver of European otter from Eastern Finland.  

PubMed

Mercury concentrations were monitored in European otter (Lutra lutra), European polecat (Mustela putorius) and European pine marten (Martes martes) collected in Eastern Finland during the period 1972-2008. Otters mainly eat fish, which is an important reason to monitor the bioaccumulation of mercury in this predator. In this species, the highest concentrations were found in fur followed by liver and kidney, and the mercury concentrations increased with increasing age and body weight. Males showed in general higher concentrations than females of otters. The food of European polecat consists of small mammals, frogs, birds and insects from both aquatic and terrestrial food chains. The mercury concentrations were lower than in otters without significant differences related to body weight or sex. In European pine martens, the concentrations were rather evenly distributed except for two specimens with high concentrations. Also, concentrations of some other metals (Al, Cd, Cu, Fe, Mn, Ni, Pb and Zn) were analysed from liver samples of otter. Possible adverse effects of mercury on the Finnish populations of these mustelids are discussed. PMID:23974535

Lodenius, M; Skarén, U; Hellstedt, P; Tulisalo, E

2014-01-01

240

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

241

Influences on Mercury Bioaccumulation Factors for the Savannah River  

Microsoft Academic Search

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous

Paller

2003-01-01

242

Influences on Mercury Bioaccumulation Factors for the Savannah River  

Microsoft Academic Search

Mercury TMDLs (Total Maximum Daily Loads) are a regulatory instrument designed to reduce the amount of mercury entering a water body and ultimately to control the bioaccumulation of mercury in fish. TMDLs are based on a BAF (bioaccumulation factor), which is the ratio of methyl mercury in fish to dissolved methyl mercury in water. Analysis of fish tissue and aqueous

M. H. Paller; J. A. Bowers; J. W. Littrell; A. V. Guanlao

2004-01-01

243

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 analysis, you will be able to conclude which species have the highest levels of mercury contamination

Miami, University of

244

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

245

Neuropsychological Functioning after Mercury Exposure  

Microsoft Academic Search

Visuographic and self-reported emotional changes were observed in dentists with elevated mercury levels. Although these changes were mild, their presence suggests subtoxic hazards associated with dental practice and underscore a continual need for maintaining mercury hygiene.

Barbara P. Uzzell

1988-01-01

246

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

247

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

248

Mercury concentrations in fish from Lake Mead, USA, related to fish size, condition, trophic level, location, and consumption risk.  

PubMed

Total mercury (Hg) concentrations were determined in the skeletal muscle of 339 fish collected during the fall of 1998 and spring of 1999 from Lake Mead, USA, the nation's largest human-made reservoir. Five species of fish representing a range of trophic levels and the lake's principal game fishes were studied. Hg generally increased with trophic level and fish size. Median Hg concentrations (ng/g wet mass) were 277 in striped bass, 168 in channel catfish, 160 in largemouth bass, 75 in bluegill, and 8 in blue tilapia. Overall, fish from Las Vegas Bay and Boulder Basin had the lowest Hg concentrations, possibly a result of biodilution in this biologically productive area. In general, fish-mercury advisories might include a warning about consuming fillet from emaciated fish, based on the finding that Hg concentrations in 59 striped bass (captured during a scarce-food season) correlated inversely ( r = -0.89, p < 0.001) with a fish nutritional-status factor. This is consistent with starvation-concentration, whereby Hg in fish muscle is lost at a slower rate than the muscle mass. The median concentration found for 139 striped bass corresponds to a recommended risk-based consumption limit of three 8-oz. (227-g) meals per month for a 70-kg adult. Finally, this paper serves as a useful archive for future research and long-term studies of Hg in Lake Mead fish. PMID:12202927

Cizdziel, J V; Hinners, T A; Pollard, J E; Heithmar, E M; Cross, C L

2002-10-01

249

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...

250

Corn extracts lower tissue arsenic level in rat  

Microsoft Academic Search

This study was carried out to see whether corn extracts could reduce the accumulation of arsenic in different tissues of rat. Exposure to arsenic (700µg\\/rat\\/day) orally for 15 days led to significant accumulation of arsenic and significant reduction in the concentration of reduced glutathione (GSH) in different tissues. While water, salt, ethanol and alkali extracts of corn were co-administered at

Noor Jahan; Alam Chowdhury; Mir Misbahuddin

2009-01-01

251

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.

252

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

253

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

254

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

255

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

PubMed

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. PMID:24656750

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

2014-05-15

256

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

257

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

258

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

259

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

260

[A theoretical study on the maximum permissible concentration of mercury vapor (author's transl)].  

PubMed

Mercury concentrations in the brain of man exposed to mercury vapor at or around the maximum permissible concentration were estimated by two mathematical models using informatins obtained from human and animal experiments. (formula: see text) Ac=concentration in the brain, C=concentration in air, V=ventilation volume, T=daily exposure time, R=proportion of mercury vapor retained after a single inhalation, D=proportion distributed to the brain, W=weight of the brain, b=elimination constant of mercury vapor in the brain, d=elimination constant of mercuric mercury in the brain, c=proportion of oxidization of elemental mercury in the brain. Model 1 is composed from a simple hypothesis that mercury vapor retained in the brain takes a single elimination coefficient, and in Model 2, a modification of Model 1, the part of elemental mercury retained in the brain is oxidized and thus has a different biological half-time from elemental mercury. During exposure to mercury vapor at the concentration of 0.05 mgHg/m3, estimated concentrations in the brain by Model 1 do not exceed a hypothetical critical concentration in the brain of 1.0 micrometerHg/g tissue but the estimated concentration by Model 2 exceeds this level. PMID:529559

Satoh, H; Suzuki, T

1979-05-01

261

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

262

Effects of numerical tolerance levels on an atmospheric chemistry model for mercury  

SciTech Connect

A Box Model was developed to investigate the atmospheric oxidation processes of mercury in the environment. Previous results indicated the most important influences on the atmospheric concentration of HgO(g) are (i) the flux of HgO(g) volatilization, which is related to the surface medium, extent of contamination, and temperature, and (ii) the presence of Cl{sub 2} in the atmosphere. The numerical solver which has been incorporated into the ORganic CHemistry Integrated Dispersion (ORCHID) model uses the Livermore Solver of Ordinary Differential Equations (LSODE). In the solution of the ODE`s, LSODE uses numerical tolerances. The tolerances effect computer run time, the relative accuracy of ODE calculated species concentrations and whether or not LSODE converges to a solution using this system of equations. The effects of varying these tolerances on the solution of the box model and the ORCHID model will be discussed.

Ferris, D.C.; Burns, D.S.; Shuford, J. [ENSCO, Inc., Melbourne, FL (United States)] [and others

1996-12-31

263

Student Exposure to Mercury Vapors.  

ERIC Educational Resources Information Center

Discusses the problem of mercury vapors caused by spills in high school and college laboratories. Describes a study which compared the mercury vapor levels of laboratories in both an older and a newer building. Concludes that the mercurial contamination of chemistry laboratories presents minimal risks to the students. (TW)

Weber, Joyce

1986-01-01

264

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...

265

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 ...

266

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

267

Metallothionein biosynthesis as a detoxification mechanism in mercury exposure in fish, spotted scat (Scatophagus argus).  

PubMed

It is of crucial importance to study on the biomarkers types to assess the specification of the pollutants and health status of marine ecosystems in environmental evaluation projects. In this respect, total metallothionein biosynthesis and mercury bioaccumulation in the liver and gills under acute mercury exposure were investigated in fish, Scat (Scatophagus argus). Spotted scat was exposed to different mercury concentrations (0, 10, 20, 30) for 24, 48, 72 h. Total MT levels were determined by enzyme-linked immunosorbent assay (ELISA) method. Mercury contents were determined through cold vapor atomic absorption spectrometry (CVAAS). Induction of MT during exposure was tissue specific, displaying different response pattern in gills and liver. Mercury accumulated in liver much higher than in gills and the latter also showed lower MT level (P<0.05). MT biosynthesis in liver showed a significant (P<0.05) increase after exposure to different mercury concentration with increase in exposure time, whereas total MT content did not significantly (P>0.05) change in gills except for 72 h exposure at 30 ?g l(-1). Nonetheless, the relationship between MT biosynthesis and Mercury bioaccumulation in both tissues was significant (P<0.05). The results suggest that this form of MT in S. argus was Hg inducible and could be extended as a biomarker of mercury pollution in marine ecosystems. PMID:20499274

Sinaie, Mahmood; Bastami, Kazem Darvish; Ghorbanpour, Masoud; Najafzadeh, Hossein; Shekari, Majid; Haghparast, Sara

2010-12-01

268

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

269

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

PubMed

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

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

271

Spatial variation of mercury levels in nesting Bonelli's eagles from Southwest Portugal: effects of diet composition and prey contamination.  

PubMed

Mercury (Hg) was determined in adult Bonelli's eagles (Hieraaetus fasciatus) and their avian prey, from samples of feathers collected between 1992 and 2001 at the nesting sites of 21 pairs in Southwest Portugal. Eagle Hg levels showed great variation, reflecting primarily differences in diet composition and food chain biomagnification. Concentrations were positively correlated with the dietary proportion of insectivorous and omnivorous birds (e.g. egrets, corvids and thrushes), with very low levels for pairs feeding mainly on herbivores (e.g. rabbits, pigeons and partridges). Differences in prey contamination among breeding territories added to dietary effects in determining variation of Hg levels in eagles, shaping a spatial pattern that was largely consistent with a source of contamination in a coal-burning power-plant lying upwind of the study area. Despite this presumed contamination, Hg levels seemed to be of little concern to this eagle population, though there might be subtle deleterious effects on the reproductive output of a few pairs. This study emphasizes the need to account for dietary effects when biomonitoring Hg contamination using birds of prey. PMID:15620600

Palma, Luís; Beja, Pedro; Tavares, Paula C; Monteiro, Luís R

2005-04-01

272

FABP4 Dynamics in Obesity: Discrepancies in Adipose Tissue and Liver Expression Regarding Circulating Plasma Levels  

PubMed Central

Background FABP4 is predominantly expressed in adipose tissue, and its circulating levels are linked with obesity and a poor atherogenic profile. Objective In patients with a wide BMI range, we analyze FABP4 expression in adipose and hepatic tissues in the settings of obesity and insulin resistance. Associations between FABP4 expression in adipose tissue and the FABP4 plasma level as well as the main adipogenic and lipolytic genes expressed in adipose tissue were also analyzed. Methods The expression of several lipogenic, lipolytic, PPAR family and FABP family genes was analyzed by real time PCR. FABP4 protein expression in total adipose tissues and its fractions were determined by western blot. Results In obesity FABP4 expression was down-regulated (at both mRNA and protein levels), with its levels mainly predicted by ATGL and inversely by the HOMA-IR index. The BMI appeared as the only determinant of the FABP4 variation in both adipose tissue depots. FABP4 plasma levels showed a significant progressive increase according to BMI but no association was detected between FABP4 circulating levels and SAT or VAT FABP4 gene expression. The gene expression of FABP1, FABP4 and FABP5 in hepatic tissue was significantly higher in tissue from the obese IR patients compared to the non-IR group. Conclusion The inverse pattern in FABP4 expression between adipose and hepatic tissue observed in morbid obese patients, regarding the IR context, suggests that both tissues may act in a balanced manner. These differences may help us to understand the discrepancies between circulating plasma levels and adipose tissue expression in obesity. PMID:23139800

Ceperuelo-Mallafré, Victoria; Garrido-Sanchez, Lourdes; Miranda, Merce; Clemente-Postigo, Mercedes; Pérez-Pérez, Rafael; Peral, Belen; Cardona, Fernando; Fernández-Real, Jose Manuel; Tinahones, Francisco J.; Vendrell, Joan

2012-01-01

273

Mercury content in commercially available finfish in the United States.  

PubMed

Seventy-seven finfish species (300 composites of three fish) were obtained from commercial vendors in six regions of the United States: Great Lakes, mid-Atlantic, New England, northwest, southeast, and southwest. Total mercury in fish muscle tissue ranged from 1 ppb (channel catfish) to 1,425 ppb (king mackerel). Of the top 10 most commonly consumed seafoods in the United States, all finfish species, including salmon species (13 to 62 ppb), Alaskan pollock (11 ppb), tilapia (16 ppb), channel catfish (1 ppb), Atlantic cod (82 ppb), and pangasius (swai) (2 ppb), had low total mercury concentrations. However, two large predatory species, king mackerel and swordfish (1,107 ppb), contained mercury concentrations above the current U.S. Food and Drug Administration action level of 1,000 ppb, indicating that consumers may be unaware that species that are high in mercury are being sold in the marketplace. PMID:25198598

Cladis, Dennis P; Kleiner, Alison C; Santerre, Charles R

2014-08-01

274

Extremely elevated methyl mercury levels in water, sediment and organisms in a Romanian reservoir affected by release of mercury from a chlor-alkali plant.  

PubMed

We examined mercury (Hg) biogeochemistry and biomagnification in the Babeni Reservoir, a system strongly affected by the release of Hg from a chlor-alkali plant. Total mercury (THg) concentrations in river water reached 88 ng L(-1) but decreased rapidly in the reservoir (to 9 ng L(-1)). In contrast, monomethylmercury (MMHg) concentrations increased from the upstream part of the reservoir to the central part (0.7 ng L(-1)), suggesting high methylation within the reservoir. Moreover, vertical water column profiles of THg and MMHg indicated that Hg methylation mainly occurred deep in the water column and at the sediment-water interface. The discharge of Hg from a chlor-alkali plant in Valcea region caused the highest MMHg concentrations ever found in non-piscivorous fish worldwide. MMHg concentrations and bioconcentration factors (BCF) of plankton and macrophytes revealed that the highest biomagnification of MMHg takes place in primary producers. PMID:24216231

Bravo, Andrea Garcia; Cosio, Claudia; Amouroux, David; Zopfi, Jakob; Chevalley, Pierre-Alain; Spangenberg, Jorge E; Ungureanu, Viorel-Gheorghe; Dominik, Janusz

2014-02-01

275

Environmental mercury concentrations in cultured low-trophic-level fish using food waste-based diets.  

PubMed

In this study, different types of food wastes were used as the major source of protein to replace the fish meal in fish feeds to produce quality fish (polyculture of different freshwater fish). During October 2011-April 2012, the concentrations of Hg in water, suspended particulate matter, and sediment of the three experimental fish ponds located in Sha Tau Kok Organic Farm were monitored, and the results were similar to or lower than those detected in commercial fish ponds around the Pearl River Delta (PRD) region (by comparing data of previous and present studies). Health risk assessments indicated that human consumption of grass carp (Ctenopharyngodon idellus), a herbivore which fed food waste feed pellets would be safer than other fish species: mud carp (Cirrhina molitorella), bighead carp (Hypophthalmichthys nobilis), and largemouth bass (Lepomis macrochirus). Due to the lower species diversity and substantially shorter food chains of the polyculture system consisting of only three fish species, the extent of Hg biomagnification was significantly lower than other polyculture ponds around PRD. Furthermore, the use of food waste instead of fish meal (mainly consisted of contaminated trash fish) further reduced the mercury accumulation in the cultured fish. PMID:25087497

Cheng, Zhang; Mo, Wing Yin; Man, Yu Bon; Lam, Cheung Lung; Choi, Wai Ming; Nie, Xiang Ping; Liu, Yi Hui; Wong, Ming Hung

2015-01-01

276

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

277

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

278

ARSENIC, CADMIUM, CHROMIUM, LEAD, MERCURY, AND SELENIUM LEVELS IN BLOOD OF FOUR SPECIES OF TURTLES FROM THE AMAZON IN BRAZIL  

PubMed Central

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 bio-indicator. 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

2014-01-01

279

Nasal Associated Lymphoid Tissue of the Syrian Golden Hamster Expresses High Levels of PrPC  

PubMed Central

The key event in the pathogenesis of the transmissible spongiform encephalopathies is a template-dependent misfolding event where an infectious isoform of the prion protein (PrPSc) comes into contact with native prion protein (PrPC) and changes its conformation to PrPSc. In many extraneurally inoculated models of prion disease this PrPC misfolding event occurs in lymphoid tissues prior to neuroinvasion. The primary objective of this study was to compare levels of total PrPC in hamster lymphoid tissues involved in the early pathogenesis of prion disease. Lymphoid tissues were collected from golden Syrian hamsters and Western blot analysis was performed to quantify PrPC levels. PrPC immunohistochemistry (IHC) of paraffin embedded tissue sections was performed to identify PrPC distribution in tissues of the lymphoreticular system. Nasal associated lymphoid tissue contained the highest amount of total PrPC followed by Peyer’s patches, mesenteric and submandibular lymph nodes, and spleen. The relative levels of PrPC expression in IHC processed tissue correlated strongly with the Western blot data, with high levels of PrPC corresponding with a higher percentage of PrPC positive B cell follicles. High levels of PrPC in lymphoid tissues closely associated with the nasal cavity could contribute to the relative increased efficiency of the nasal route of entry of prions, compared to other routes of infection. PMID:25642714

Clouse, Melissa D.; Shikiya, Ronald A.; Bartz, Jason C.; Kincaid, Anthony E.

2015-01-01

280

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

281

Predicting bone remodeling around tissue- and bone-level dental implants used in reduced bone width.  

PubMed

The objective of this study was to predict time-dependent bone remodeling around tissue- and bone-level dental implants used in patients with reduced bone width. The remodeling of bone around titanium tissue-level, and titanium and titanium-zirconium alloy bone-level implants was studied under 100 N oblique load for one month by implementing the Stanford theory into three-dimensional finite element models. Maximum principal stress, minimum principal stress, and strain energy density in peri-implant bone and displacement in x- and y- axes of the implant were evaluated. Maximum and minimum principal stresses around tissue-level implant were higher than bone-level implants and both bone-level implants experienced comparable stresses. Total strain energy density in bone around titanium implants slightly decreased during the first two weeks of loading followed by a recovery, and the titanium-zirconium implant showed minor changes in the axial plane. Total strain energy density changes in the loading and contralateral sides were higher in tissue-level implant than other implants in the cortical bone at the horizontal plane. The displacement values of the implants were almost constant over time. Tissue-level implants were associated with higher stresses than bone-level implants. The time-dependent biomechanical outcome of titanium-zirconium alloy bone-level implant was comparable to the titanium implant. PMID:23876712

Eser, Atilim; Tonuk, Ergin; Akca, Kivanc; Dard, Michel M; Cehreli, Murat Cavit

2013-09-01

282

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...

283

The Empire Knight: Patterns of mercury contamination in sediment and biota at a marine site  

SciTech Connect

The Empire Knight, a merchant ship carrying approximately 7.3 metric tons of elemental mercury in its cargo, sank in a storm off the Maine coast in 1 944. Unique attributes of the site include the deep water marine conditions (80 m) and mercury originally in elemental form. Recent evaluations of the site were undertaken to determine environmental risk of the remaining mercury and possible remedial actions. Data collected in 1993 for this risk evaluation included sediment core samples, and a variety of biota samples. Biota were analyzed for total and methylmercury, and the following patterns examined: percent methylmercury, variability between species groups, and spatial patterns related to sediment contamination. Sediment contamination was largely confined to the immediate area near the wreck, with levels decreasing to background within 60 m. Invertebrates within this area had elevated levels of mercury in tissue. Most contamination was in an inorganic form, with percentages of methyl to total mercury below 20%, except for crab and lobster. Most of the residual mercury appears to be largely unavailable to biota, with local invertebrates comprising the main biological receptors. Evidence of bioaccumulation of mercury in higher trophic level organisms was not found, thus mercury did not appear to be a source of contamination beyond the immediate area the wreck.

Hoff, R.Z. [NOAA Hazmat, Seattle, WA (United States)

1995-12-31

284

Mercury accumulation in largemouth bass (Micropterus salmoides) in a Florida Lake  

Microsoft Academic Search

Rates of mercury accumulation were examined in male and female largemouth bass (Micropterus salmoides) from Lake Tohopekaliga, Florida, to establish methods for fish consumption advisories for the protection of human health. In addition, concentrations were determined in five lower trophic level fish species. Total mercury concentrations in adult largemouth bass muscle tissue ranged from 0.16 to 1.10 µg\\/g (fresh weight)

T. R. Lange; H. E. Royals; L. L. Connor

1994-01-01

285

Theoretical bounds for the influence of tissue-level ductility on the apparent-level strength of human trabecular bone.  

PubMed

The role of tissue-level post-yield behavior on the apparent-level strength of trabecular bone is a potentially important aspect of bone quality. To gain insight into this issue, we compared the apparent-level strength of trabecular bone for the hypothetical cases of fully brittle versus fully ductile failure behavior of the trabecular tissue. Twenty human cadaver trabecular bone specimens (5mm cube; BV/TV=6-36%) were scanned with micro-CT to create 3D finite element models (22-micron element size). For each model, apparent-level strength was computed assuming either fully brittle (fracture with no tissue ductility) or fully ductile (yield with no tissue fracture) tissue-level behaviors. We found that the apparent-level ultimate strength for the brittle behavior was only about half the value of the apparent-level 0.2%-offset yield strength for the ductile behavior, and the ratio of these brittle to ductile strengths was almost constant (mean±SD=0.56±0.02; n=20; R(2)=0.99 between the two measures). As a result of this small variation, although the ratio of brittle to ductile strengths was positively correlated with the bone volume fraction (R(2)=0.44, p=0.01) and structure model index (SMI, R(2)=0.58, p<0.01), these effects were small. Mechanistically, the fully ductile behavior resulted in a much higher apparent-level strength because in this case about 16-fold more tissue was required to fail than for the fully brittle behavior; also, there was more tensile- than compressive-mode of failure at the tissue level for the fully brittle behavior. We conclude that, in theory, the apparent-level strength behavior of human trabecular bone can vary appreciably depending on whether the tissue fails in a fully ductile versus fully brittle manner, and this effect is largely constant despite appreciable variations in bone volume fraction and microarchitecture. PMID:23497799

Nawathe, Shashank; Juillard, Frédéric; Keaveny, Tony M

2013-04-26

286

Mercury in the Amazon.  

PubMed

Release and spreading of mercury from gold mining is a widespread problem in the Amazon area. Today we have rather good knowledge of the mercury situation. Tens of investigations have considered mainly concentrations in fish and human hair. Metallic mercury is used for amalgamation of gold, and the mercury is released by evaporation at reburning sites. The first extraction (burning) is performed in the field at the garimpos and the second (reburning) in gold shops in towns. This practice may cause severe exposure to elemental mercury by inhalation for people working with gold purification. Mercury is also released in substantial amounts to rivers and lakes. This mercury may be bioaccumulated as methylmercury in aquatic food chains. Predatory fish often contain mercury in concentrations that far exceed the safety norms in Brazil. As many people eat fish daily, there is a high exposure to methylmercury. Neurological disorders have been found in exposed persons. Methylmercury concentrations in hair are often at levels that may cause clinical symptoms of Minamata disease. The greatest health hazard index values have been estimated for people eating contaminated fish. PMID:9666740

Lodenius, M; Malm, O

1998-01-01

287

Chronic low-level mercury exposure, BDNF polymorphism, and associations with self-reported symptoms and mood.  

PubMed

Recent reports have described neurobehavioral impairments in human subjects carrying a V66M polymorphism in the gene encoding brain-derived neurotrophic factor (BDNF). Inasmuch as ventral nervous system (CNS) deficits associated with this BDNF polymorphism are similar to those observed among subjects with chronic exposure to elemental mercury (Hg degrees ), we examined the potential effect of this BDNF polymorphism on symptoms and mood in an established cohort of dental practitioners with chronic low-level Hg degrees exposure. Self-reported symptoms and mood were obtained by computerized questionnaire from 193 male dentists (DTs) and 230 female dental assistants (DAs). Spot urine samples were analyzed for mercury concentrations to evaluate recent exposure. Detailed work histories were obtained to calculate chronic indices of Hg degrees exposure. Buccal cell samples were obtained to identify the V66M polymorphism of BDNF. Scores for 11 current and 12 recent and chronic symptom groups, along with six mood factors, were evaluated with respect to recent and chronic Hg degrees exposure and BDNF polymorphism. Multiple regression analysis controlled for age, race, socioeconomic status, tobacco and alcohol use, self-reported health problems, and medications. Separate evaluations were conducted for DTs and DAs. Twenty-three associations between recent or chronic Hg degrees exposure and BDNF status and self-reported symptoms were observed with p < 0.10. All but three were in the expected direction (symptom scores increasing with Hg degrees exposure or BDNF polymorphism), and all but six were among DAs. All eight correlations between chronic exposure indices and recent and chronic symptoms among DAs were in the expected direction. All seven associations between BDNF and symptoms were in the expected direction and split between DTs and DAs. All three associations with mood factors were among DAs and in the expected direction. These results indicate that among DAs very low levels of occupational Hg degrees exposure are associated with increased symptoms. The BDNF polymorphism is also associated with increased symptom and mood scores. Notably, Hg degrees and BDNF polymorphism were additive with respect to their associations with the same symptom group. PMID:15254338

Heyer, Nicholas J; Echeverria, Diana; Bittner, Alvah C; Farin, Federico M; Garabedian, Claire C; Woods, James S

2004-10-01

288

Soft Tissue Discrimination Using Magnetic Resonance Elastography with a New Elastic Level Set Model  

NASA Astrophysics Data System (ADS)

Magnetic resonance elastography (MRE) noninvasively images the propagation of mechanical waves within soft tissues. The elastic properties of soft tissues can then be quantified from MRE wave snapshots. Various algorithms have been proposed to obtain their inversion for soft tissue elasticity. Anomalies are assumed to be discernible in the elasticity map. We propose a new elastic level set model to directly detect and track abnormal soft tissues in MRE wave images. It is derived from the Mumford-Shah functional, and employs partial differential equations for function modeling and smoothing. This level set model can interpret MRE wave images without elasticity reconstruction. The experimental results on synthetic and real MRE wave images confirm its effectiveness for soft tissue discrimination.

Li, Bing Nan; Chui, Chee Kong; Ong, Sim Heng; Washio, Toshikatsu; Numano, Tomokazu; Chang, Stephen; Venkatesh, Sudhakar; Kobayashi, Etsuko

289

Inorganic: the other mercury.  

PubMed

There is a broad array of mercury species to which humans may be exposed. While exposure to methylmercury through fish consumption is widely recognized, the public is less aware of the sources and potential toxicity of inorganic forms of mercury. Some oral and laboratory thermometers, barometers, small batteries, thermostats, gas pressure regulators, light switches, dental amalgam fillings, cosmetic products, medications, cultural/religious practices, and gold mining all represent potential sources of exposure to inorganic forms of mercury. The route of exposure, the extent of absorption, the pharmacokinetics, and the effects all vary with the specific form of mercury and the magnitude and duration of exposure. If exposure is suspected, a number of tissue analyses can be conducted to confirm exposure or to determine whether an exposure might reasonably be expected to be biologically significant. By contrast with determination of exposure to methylmercury, for which hair and blood are credible indicators, urine is the preferred biological medium for the determination of exposure to inorganic mercury, including elemental mercury, with blood normally being of value only if exposure is ongoing. Although treatments are available to help rid the body of mercury in cases of extreme exposure, prevention of exposure will make such treatments unnecessary. Knowing the sources of mercury and avoiding unnecessary exposure are the prudent ways of preventing mercury intoxication. When exposure occurs, it should be kept in mind that not all unwanted exposures will result in adverse health consequences. In all cases, elimination of the source of exposure should be the first priority of public health officials. PMID:18044248

Risher, John F; De Rosa, Christopher T

2007-11-01

290

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

291

Expression of Hepatic Metallothionein Messenger RNA in Feral and Caged Fish Species Correlates with Muscle Mercury Levels  

Microsoft Academic Search

Metallothioneins (MTs) are low-molecular-weight cytosolic proteins that are induced by cellular stress as well as exposure to various heavy metals including mercury. Excessive residues of mercury have recently been identified in various fish species of the lower Quachita River system in Arkansas. Fillets of mature largemouth bass (Micropterus salmoides) collected from Woodard Lake, an ox-bow lake of the Ouachita River,

D. Schlenk; Y. S. Zhang; J. Nix

1995-01-01

292

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

293

Mercury heavy-metal-induced physiochemical changes and genotoxic alterations in water hyacinths [Eichhornia crassipes (Mart.)].  

PubMed

Mercury heavy metal pollution has become an important environmental problem worldwide. Accumulation of mercury ions by plants may disrupt many cellular functions and block normal growth and development. To assess mercury heavy metal toxicity, we performed an experiment focusing on the responses of Eichhornia crassipes to mercury-induced oxidative stress. E. crassipes seedlings were exposed to varying concentrations of mercury to investigate the level of mercury ions accumulation, changes in growth patterns, antioxidant defense mechanisms, and DNA damage under hydroponics system. Results showed that plant growth rate was significantly inhibited (52 %) at 50 mg/L treatment. Accumulation of mercury ion level were 1.99 mg/g dry weight, 1.74 mg/g dry weight, and 1.39 mg/g dry weight in root, leaf, and petiole tissues, respectively. There was a decreasing trend for chlorophyll a, b, and carotenoids with increasing the concentration of mercury ions. Both the ascorbate peroxidase and malondialdehyde contents showed increased trend in leaves and roots up to 30 mg/L mercury treatment and slightly decreased at the higher concentrations. There was a positive correlation between heavy metal dose and superoxide dismutase, catalase, and peroxidase antioxidative enzyme activities which could be used as biomarkers to monitor pollution in E. crassipes. Due to heavy metal stress, some of the normal DNA bands were disappeared and additional bands were amplified compared to the control in the random amplified polymorphic DNA (RAPD) profile. Random amplified polymorphic DNA results indicated that genomic template stability was significantly affected by mercury heavy metal treatment. We concluded that DNA changes determined by random amplified polymorphic DNA assay evolved a useful molecular marker for detection of genotoxic effects of mercury heavy metal contamination in plant species. PMID:25323404

Malar, Srinivasan; Sahi, Shivendra Vikram; Favas, Paulo J C; Venkatachalam, Perumal

2014-10-18

294

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

295

Pattern of mercury accumulation in different tissues of migratory and resident birds: Western reef heron (Egretta gularis) and Siberian gull (Larus heuglini) in Hara International Wetland-Persian Gulf.  

PubMed

The Hara Mangrove Forest of the Persian Gulf is undergoing increasing pollution from industrial, municipal, and petroleum sources; however, little research in ecotoxicology has been carried out in this ecosystem. In the present study, mercury distribution and accumulation were investigated in muscle, liver, kidney, and feather of the resident Western reef heron (n?=?15) and the migratory Siberian gull (n?=?15). We also evaluated the relation between Hg concentrations, sex, and age (juvenile vs. adult). Results showed that the highest concentrations of Hg were recorded in the feather (35?±?0.14-3.0?±?0.27 mg kg(-1) dw) and at 3.7-, 1.6-, and 1.3-fold in muscle, kidney, and liver, respectively. Concentrations of mercury in tissues of migratory birds were two times higher than in resident birds; geographical differences and feeding habits were used to explain these variations. We found a weak relationship between Hg concentrations in feathers and internal tissues (r???0.50); conversely, liver presented strong positive correlations with other soft tissues, especially kidney (p?>?0.05; r?=?0.82). Results showed that sex and age have no significant effects on T-Hg accumulation in these birds (p?>?0.05; r?mercury pollution in this region. PMID:25492705

Majidi, Yousef; Bahramifar, Nader; Ghasempouri, Seyed Mahmoud

2015-01-01

296

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

297

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

298

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

299

Detection of Genetically Altered Copper Levels in Drosophila Tissues by Synchrotron X-Ray Fluorescence Microscopy  

PubMed Central

Tissue-specific manipulation of known copper transport genes in Drosophila tissues results in phenotypes that are presumably due to an alteration in copper levels in the targeted cells. However direct confirmation of this has to date been technically challenging. Measures of cellular copper content such as expression levels of copper-responsive genes or cuproenzyme activity levels, while useful, are indirect. First-generation copper-sensitive fluorophores show promise but currently lack the sensitivity required to detect subtle changes in copper levels. Moreover such techniques do not provide information regarding other relevant biometals such as zinc or iron. Traditional techniques for measuring elemental composition such as inductively coupled plasma mass spectroscopy are not sensitive enough for use with the small tissue amounts available in Drosophila research. Here we present synchrotron x-ray fluorescence microscopy analysis of two different Drosophila tissues, the larval wing imaginal disc, and sectioned adult fly heads and show that this technique can be used to detect changes in tissue copper levels caused by targeted manipulation of known copper homeostasis genes. PMID:22053217

Lye, Jessica C.; Hwang, Joab E. C.; Paterson, David; de Jonge, Martin D.; Howard, Daryl L.; Burke, Richard

2011-01-01

300

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...

301

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

302

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...

303

A screening level probabilistic risk assessment of mercury in Florida Everglades food webs.  

PubMed

A screening level probabilistic assessment of risks was performed on three species of piscivorous wildlife at the top of Everglades aquatic food webs: the American alligator (Alligator mississippiensis), the great egret (Egretta alba), and the raccoon (Procyon lotor varius). Ranges of dietary exposure concentrations (and probability distribution functions) were derived for two general areas of the Everglades: Shark Slough and the southcentral Everglades (highly contaminated with Hg), and the northern Everglades (a lower Hg contaminated area in and near Water Conservation Area 1). Ranges of toxicity reference values and probability distribution functions were derived from literature on the toxicity of dietary methyl Hg to birds and mammals. Probability distributions of risk estimates for each receptor were generated using Monte Carlo simulations and indicated that piscivorous wildlife feeding in the south-central region of the Everglades are at high risk from consumption of Hg-contaminated prey. Alligators had 100% exceedences of chronic risk thresholds, and great egrets had 99% exceedences. In the northern Everglades, exceedences of chronic risk thresholds were substantially lower but were still present (6-34% exceedences). Results support previous studies suggesting that top predators of the Everglades may be at risk from Hg contamination and indicate that Hg risks are location-dependent. PMID:11139184

Duvall, S E; Barron, M G

2000-11-01

304

Linking Influenza Virus Tissue Tropism to Population-Level Reproductive Fitness  

PubMed Central

Influenza virus tissue tropism defines the host cells and tissues that support viral replication and contributes to determining which regions of the respiratory tract are infected in humans. The location of influenza virus infection along the respiratory tract is a key determinant of virus pathogenicity and transmissibility, which are at the basis of influenza burdens in the human population. As the pathogenicity and transmissibility of influenza virus ultimately determine its reproductive fitness at the population level, strong selective pressures will shape influenza virus tissue tropisms that maximize fitness. At present, the relationships between influenza virus tissue tropism within hosts and reproductive fitness at the population level are poorly understood. The selective pressures and constraints that shape tissue tropism and thereby influence the location of influenza virus infection along the respiratory tract are not well characterized. We use mathematical models that link within-host infection dynamics in a spatially-structured human respiratory tract to between-host transmission dynamics, with the aim of characterizing the possible selective pressures on influenza virus tissue tropism. The results indicate that spatial heterogeneities in virus clearance, virus pathogenicity or both, resulting from the unique structure of the respiratory tract, may drive optimal receptor binding affinity–that maximizes influenza virus reproductive fitness at the population level–towards sialic acids with ?2,6 linkage to galactose. The expanding cell pool deeper down the respiratory tract, in association with lower clearance rates, may result in optimal infectivity rates–that likewise maximize influenza virus reproductive fitness at the population level–to exhibit a decreasing trend towards deeper regions of the respiratory tract. Lastly, pre-existing immunity may drive influenza virus tissue tropism towards upper regions of the respiratory tract. The proposed framework provides a new template for the cross-scale study of influenza virus evolutionary and epidemiological dynamics in humans. PMID:22952637

Reperant, Leslie A.; Kuiken, Thijs; Grenfell, Bryan T.; Osterhaus, Albert D. M. E.; Dobson, Andrew P.

2012-01-01

305

Folate levels in mucosal tissue but not methylenetetrahydrofolate reductase polymorphisms are associated with gastric carcinogenesis  

PubMed Central

AIM: To evaluate whether folate levels in mucosal tissue and some common methylenetetrahydrofolate reductase (MTHFR) variants are associated with the risk of gastric cancer through DNA methylation. METHODS: Real-time PCR was used to study the expression of tumor related genes in 76 mucosal tissue samples from 38 patients with gastric cancer. Samples from the gastroscopic biopsy tissues of 34 patients with chronic superficial gastritis (CSG) were used as controls. Folate concentrations in these tissues were detected by the FOL ACS: 180 automated chemiluminescence system. MTHFR polymorphisms were analyzed by PCR-RFLP, and the promoter methylation of tumor-related genes was determined by methylation-specific PCR (MSP). RESULTS: Folate concentrations were significantly higher in CSG than in cancerous tissues. Decreased expression and methylation of c-myc accompanied higher folate concentrations. Promoter hypermethylation and loss of p16INK4A in samples with MTHFR 677CC were more frequent than in samples with the 677TT or 677CT genotype. And the promoter hypermethylation and loss of p21WAF1 in samples with MTHFR 677CT were more frequent than when 677CC or 677TT was present. The 677CT genotype showed a non-significant higher risk for gastric cancer as compared with the 677CC genotype. CONCLUSION: Lower folate levels in gastric mucosal tissue may confer a higher risk of gastric carcinogenesis through hypomethylation and overexpression of c-myc. PMID:17171786

Weng, Yu-Rong; Sun, Dan-Feng; Fang, Jing-Yuan; Gu, Wei-Qi; Zhu, Hong-Yin

2006-01-01

306

Mercury and Your Health  

MedlinePLUS

... the Risk of Exposure to Mercury Learn About Mercury What is Mercury? What is Metallic Mercury? Toxicological ... PDF - 3.6MB) En Español (PDF - 1.8MB) Mercury Resources CDC’s Fourth National Report on Human Exposure ...

307

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

308

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

309

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

PubMed

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

310

Chronic treatment with anesthetic propofol attenuates ?-amyloid protein levels in brain tissues of aged mice  

PubMed Central

Alzheimer’s disease (AD) is the most common form of dementia. At the present time, however, AD still lacks effective treatments. Our recent studies showed that chronic treatment with anesthetic propofol attenuated brain caspase-3 activation and improved cognitive function in aged mice. Accumulation of ?-amyloid protein (A?) is a major component of the neuropathogenesis of AD dementia and cognitive impairment. We therefore set out to determine the effects of chronic treatment with propofol on A? levels in brain tissues of aged mice. Propofol (50 mg/kg) was administrated to aged (18 month-old) wild-type mice once a week for 8 weeks. The brain tissues of mice were harvested one day after the final propofol treatment. The harvested brain tissues were then subjected to enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Here we report that the propofol treatment reduced A? (A?40 and A?42) levels in the brain tissues of the aged mice. Moreover, the propofol treatment decreased the levels of ?-site amyloid precursor protein cleaving enzyme (the enzyme for A? generation), and increased the levels of neprilysin (the enzyme for A? degradation) in the brain tissues of the aged mice. These results suggested that the chronic treatment with propofol might reduce brain A? levels potentially via decreasing brain levels of ?-site amyloid precursor protein cleaving enzyme, thus decreasing A? generation; and via increasing brain neprilysin levels, thus increasing A? degradation. These preliminary findings from our pilot studies have established a system and postulated a new hypothesis for future research. PMID:24725331

2014-01-01

311

Metabolic factors, adipose tissue, and plasminogen activator inhibitor-1 levels in Type 2 diabetes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plasminogen activator inhibitor-1 (PAI-1) production by adipose tissue is increased in obesity, and its circulating levels are high in type 2 diabetes. PAI-1 increases cardiovascular risk by favoring clot stability, interfering with vascular remodeling, or both. We investigated in obese diabetic per...

312

Effect of dietary copper and zinc levels on tissue copper, zinc, and iron in male rats  

Microsoft Academic Search

The interaction between dietary copper and zinc as determined by tissue concentrations of trace elements was investigated\\u000a in male Sprague-Dawley rats. Animals were fed diets in a factorial design with two levels of copper (0.5, 5 ?g\\/g) and five\\u000a levels of zinc (1, 4.5, 10, 100, 1000 ?g\\/g) for 42 d. In rats fed the low copper diet, as dietary

Carl L. Keen; Nancy H. Reinstein; Jo Goudey-Lefevre; Michael Lefevre; Bo Lönnerdal; Barbara O. Schneeman; Lucille S. Hurley

1985-01-01

313

ELF (extremely-low-frequency) field interactions at the animal, tissue and cellular levels  

SciTech Connect

A description is given of the fundamental physical properties of extremely-low-frequency (ELF) electromagnetic fields, and the mechanisms through which these fields interact with the human body at a macroscopic level. Biological responses to ELF fields at the tissue, cellular and molecular levels are summarized, including new evidence that ELF field exposure produces alterations in gene expression and the cytoplasmic concentrations of specific proteins.

Tenforde, T.S.

1990-10-01

314

Ecological effects of mercury in aquatic ecosystems  

SciTech Connect

As a result of former mining operations, roughly 100 tons of mercury were released into Clear Lake, California. In 1992 the authors conducted a baseline survey designed to evaluate the levels and potential effects of mercury within this aquatic ecosystem. Both surficial sediments and cores confirm a clear exponential decline in total mercury and methyl mercury as a function of distance from the mine site. The ratio of methyl/total mercury in surficial sediments, however, increases exponentially as a function of distance from the mine. Declines in total mercury in water were not as steep as for sediments. Plankton, oligochaetes and chironomids also exhibited exponential declines in total mercury but not methyl mercury as a function of distance from the mine. Patterns of invertebrate population and community level parameters will be discussed in relation to mercury and other potential pollutants. Fish showed increasing mercury levels with increasing body size and the following species specific differences: carp < silversides < channel catfish < largemouth bass. Some higher than expected levels of methyl mercury were found at sites distant from the mine. An hypothesis to explain these methyl mercury distributions as a function of bioavailability will be presented.

Suchanek, T.H.; Richerson, P.J. [Univ. of California, Davis, CA (United States). Division of Environmental Studies

1994-12-31

315

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

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

316

Physiological responses to mercury in feral carp populations inhabiting the low Ebro River (NE Spain), a historically contaminated site.  

PubMed

The low Ebro River course (Northeast Spain) is historically affected by mercury pollution due to a chlor-alkali plant operating at the town of Flix for more than a century. River sediments analysed during the last 10 years showed high mercury levels in the river section starting just downstream the factory and spanning some 90km, down to the river delta. The possible environmental impact was studied by a combination of field and laboratory studies. Mercury concentrations in liver, kidney and muscle of feral carp (Cyprinus carpio) sampled downstream Flix were one to two orders of magnitude higher than those from carps sampled upstream Flix. Elevated levels of mercury in these samples associated with significant increases on the concentration of reduced glutathione (GSH) in liver and on mRNA expression of two metallothionein genes, MT1 and MT2, in kidney and, partially, in scales, but not in liver. Conversely, no biochemical evidence for oxidative stress or DNA damage was found in these tissues. Non-contaminated carps subjected to intraperitoneal mercury injection resulted in a 20-fold increase of MT1 and MT2 mRNA levels in carp kidney, with minimal changes in liver levels. Our data suggests the coordinate increase of metallothionein mRNA in kidney and of GSH in liver constitutes an excellent marker of exposure to sub-toxic mercury levels in carps. This study also demonstrates that apparently healthy fish populations may exceed the mercury contamination acceptable for human consumption. PMID:19482362

Navarro, Anna; Quirós, Laia; Casado, Marta; Faria, Melissa; Carrasco, Luís; Benejam, Lluís; Benito, Josep; Díez, Sergi; Raldúa, Demetrio; Barata, Carlos; Bayona, Josep M; Piña, Benjamin

2009-06-28

317

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

318

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.

Meagher, Richard B.

2005-06-01

319

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

320

Trace element distribution in heart tissue sections studied by nuclear microscopy is changed in coxsackie virus B3 myocarditis in methyl mercury-exposed mice  

Microsoft Academic Search

Methyl mercury (MeHg) has been shown to change Coxsackie virus type B3 (CB3) myocarditis in a direction compatible with the\\u000a development of chronic disease. Murine models of CB3 myocarditis closely mimic the pathogenesis in humans. There are also\\u000a indications that metals, such as mercury, and trace elements may interact and adversely affect viral replication and development\\u000a of inflammatory lesions. The

Nils-Gunnar Ilbäck; Ulf Lindh; Lars Wesslén; Jan Fohlman; Göran Friman

2000-01-01

321

Landfill impacts on aquatic plant communities and tissue metal levels at Indiana Dunes National Lakeshore  

SciTech Connect

One important environmental issue facing Northwest Indiana and park management at Indiana Dunes National Lakeshore (INOU) is the contamination of water, sediment and biota by persistent toxic substances. Aquatic plant communities were used to evaluate the water/organismal quality of the Grand Calumet Lagoons and two dunal ponds (pannes) at Gary, Indiana, which are partially located in the Miller Woods Unit of INDU. The lagoon is divided into several areas, the USX Lagoon is located between sections of a large industrial landfill (steel slag and other material). The Marquette Lagoon is located further away from the landfill and tends to be upgradient from the landfill. The West Panne (WP) is located next to the landfill, while the East Panne (EP) is separated from the landfill and the WP by a high dune ridge. Plant populations shift toward fewer submergent aquatics, with a higher abundance of tolerant taxa in the western section of the USX Lagoon. These differences are supported by cluster analysis. Heavy metals in root tissue of Scirpus americanus and other plant species from the pannes were significantly higher than those found in shoots. Shoot tissue metal levels in plants collected from the lagoons were higher than root tissue metal levels. The WP site has the most elevated tissue metal levels for most metals assayed, while the EP site shows similar contaminant levels. The plant distributions observed and tissue metal concentrations measured suggest that INDU`s aquatic plant community has been affected by the industrial landfill and that there exists a hydrological connection between the ponds.

Stewart, P.M. [National Biological Service, Porter, IN (United States). Lake Michigan Ecological Station; Scribailo, R.W. [Purdue Univ.North Central, Westville, IN (United States). Section of Biology and Chemistry

1995-12-31

322

The Chemical Nature of Mercury in Human Brain Following Poisoning or Environmental Exposure  

PubMed Central

Methylmercury is among the most potentially toxic species to which human populations are exposed, both at high levels through poisonings and at lower levels through consumption of fish and other seafood. However, the molecular mechanisms of methylmercury toxicity in humans remain poorly understood. We used synchrotron X-ray absorption spectroscopy (XAS) to study mercury chemical forms in human brain tissue. Individuals poisoned with high levels of methylmercury species showed elevated cortical selenium with significant proportions of nanoparticulate mercuric selenide plus some inorganic mercury and methylmercury bound to organic sulfur. Individuals with a lifetime of high fish consumption showed much lower levels of mercuric selenide and methylmercury cysteineate. Mercury exposure did not perturb organic selenium levels. These results elucidate a key detoxification pathway in the central nervous system and provide new insights into the appropriate methods for biological monitoring. PMID:22826746

2010-01-01

323

Mercury Bubbles  

Microsoft Academic Search

I HAVE on several occasions noticed the beautiful bubbles described by Mr. Wright and Sir William Crookes (pp. 8 and 37). On each occasion I was purifying mercury in the following way. I half filled a rather large Woulffe's bottle with mercury and poured on to it weak nitric acid. Then, in order to keep, the whole in a state

A. T. Hare

1908-01-01

324

A case for in vivo mass-independent fractionation of mercury isotopes in fish  

NASA Astrophysics Data System (ADS)

The recent discovery of mass-independent fractionation of mercury isotopes allows new constraints to be placed on the mercury cycle. Here we report new Hg isotopic analyses of zooplankton and fish from different trophic levels of a freshwater lake (Lake Jackson, Florida) bearing systematic mass-independent fractionation of mercury isotopes. Fish muscle tissues show a progressive enrichment in the odd-mass mercury isotopes having odd atomic mass numbers (199 and 201) with increasing trophic level. Trophic level was determined based on nitrogen isotopic composition as well as fish stomach content. Zooplankton in the lake contain mercury with ?199Hg and ?201Hg values of +0.43 (±0.07)‰ and +0.44 (±0.07)‰, respectively. The ?199Hg values increase by ˜1‰ from ˜+0.4‰ in zooplankton, juvenile bluegill, and several other small fishes to ?199Hg = +1.36‰ for the Florida gar, which is the top predator fish in the lake. Previous observations of odd-mass-number isotope enrichment of mercury have been explained by photoreduction and demethylation of methyl mercury in the water column or as isotope effects related to microbial methylation. However, our data and the data of Jackson et al. (2008) are also consistent with in vivo production of mass-independent fractionation. Considering the alternatives, mass-independent fractionation by metabolic processes is the most straightforward explanation for the mercury isotope data. There are two known mechanisms for mass-independent fractionation of mercury, i.e., the nuclear volume effect and the magnetic isotope effect. While the data are insufficient to serve as proof, the magnitude of the mass-independent effect and the nearly equal enrichment of 199Hg and 201Hg seem most suggestive of a magnetic isotope effect.

Das, Reshmi; Salters, Vincent J. M.; Odom, A. Leroy

2009-11-01

325

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

326

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

327

Dental Amalgam Exposure and Urinary Mercury Levels in Children: The New England Children’s Amalgam Trial  

Microsoft Academic Search

METHODS: We analyzed time-sensitive longitudinal amalgam exposure data in children randomized to amalgam restorations (n = 267) during the 5-year New England Children's Amalgam Trial. We calculated 8 measures of amalgam, evaluating current versus cumulative exposure, teeth versus sur- faces, and total versus posterior occlusal amalgams. Urine samples collected during follow-up years 3-5 were analyzed for mercury excretion. Multivariate models

Nancy Nairi Maserejian; Felicia L. Trachtenberg; Susan F. Assmann; Lars Barregard

2007-01-01

328

Validation of freezing tissues and cells for analysis of DNA strand break levels by comet assay  

PubMed Central

The comet analysis of DNA strand break levels in tissues and cells has become a common method of screening for genotoxicity. The large majority of published studies have used fresh tissues and cells processed immediately after collection. However, we have used frozen tissues and cells for more than 10 years, and we believe that freezing samples improve efficiency of the method. We compared DNA strand break levels measured in fresh and frozen bronchoalveolar cells, and lung and liver tissues from mice exposed to the known mutagen methyl methanesulphonate (0, 25, 75, 112.5mg/kg). We used a high-throughput comet protocol with fully automated scoring of DNA strand break levels. The overall results from fresh and frozen samples were in agreement [R 2 = 0.93 for %DNA in tail (%TDNA) and R 2 = 0.78 for tail length (TL)]. A slightly increased %TDNA was observed in lung and liver tissue from vehicle controls; and TL was slightly reduced in bronchoalveolar lavage cells from the high-dose group. In our comet protocol, a small block of tissue designated for comet analysis is frozen immediately at tissue collection and kept deep frozen until rapidly homogenised and embedded in agarose. To demonstrate the feasibility of long-term freezing of samples, we analysed the day-to-day variation of our internal historical negative and positive comet assay controls collected over a 10-year period (1128 observations, 11 batches of frozen untreated and H2O2-treated A549 lung epithelial cells). The H2O2 treatment explained most of the variation 57–77% and the day-to-day variation was only 2–12%. The presented protocol allows analysis of samples collected over longer time span, at different locations, with reduced variation by reducing number of electrophoreses and is suitable for both toxicological and epidemiological studies. The use of frozen tissues; however, requires great care during preparation before analysis, with handling as a major risk factor. PMID:24136994

Jackson, Petra

2013-01-01

329

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

330

Mercury contamination study for flight system safety  

NASA Technical Reports Server (NTRS)

The effects and prevention of possible mercury pollution from the failure of solar electric propulsion spacecraft using mercury propellant were studied from tankage loading of post launch trajector injection. During preflight operations and initial flight mode there is little danger of mercury pollution if proper safety precautions are taken. Any spillage on the loading, mating, transportation, or launch pad areas is obvious and can be removed by vacuum cleaning soil and chemical fixing. Mercury spilled on Cape Kennedy ground soil will be chemically complexed and retained by the sandstone subsoil. A cover layer of sand or gravel on spilled mercury which has settled to the bottom of a water body adjacent to the system operation will control and eliminate the formation of toxic organic mercurials. Mercury released into the earth's atmosphere through leakage of a fireball will be diffused to low concentration levels. However, gas phase reactions of mercury with ozone could cause a local ozone depletion and result in serious ecological hazards.

Gorzynski, C. S., Jr.; Maycock, J. N.

1972-01-01

331

Quinolone levels in serum and maxillofacial tissues under ibuprofen co-administration following surgical trauma.  

PubMed

Administration of antibiotics is considered to be an important factor, during or after operational procedures in the maxillofacial area, in order to avoid post-surgical complications. Furthermore, administration of anti-inflammatory drugs is often prescribed for control of the post-operative pain. The aim of this study was to determine the levels of quinolones in serum and tissues (parotid gland, tongue, mandible), during traumatic injury in the oral cavity, with or without co-administration of ibuprofen, a non-steroidal anti-inflammatory drug. Four groups of Wistar rats, (A, B control), (C, D experimental) were used. In the experimental group, traumatic injury was performed through the whole length of the cheek. Groups B and D received ibuprofen. The quinolone levels in serum and tissues were estimated by the inhibition zone of B. subtilis. Free fatty acid (FFA) levels and the adrenal weight, considered as a stress index, were increased in trauma groups. Quinolone concentrations in serum and in most of the tissues were significantly higher in the experimental groups compared to the controls. However, the co-administration of ibuprofen caused a higher increase of the quinolone levels in the control animals than in the experimental groups. PMID:15758358

Trachilis, A; Saranteas, T; Potamianou, A; Mourouzis, C; Tesseromatis, C

2003-06-01

332

A homogenization sampling procedure for calculating trabecular bone effective stiffness and tissue level stress.  

PubMed

A homogenization sampling procedure is introduced which allows computation of effective trabecular bone stiffness and individual trabecula level stress based on precise models of trabecular bone architecture. Three-dimensional digitized images of 53 trabecular bone specimens with a resolution of 50 microns per voxel were directly converted into three-dimensional finite element meshes by making each voxel an 8-node isoparametric brick element. Owing to the large mesh of 8000 elements, an element-by-element preconditioned conjugate gradient (EBEPCG) program was written to solve the local homogenization finite element equations. Predicted effective stiffness measures correlated well with experimental results (R2 > 0.73). The predicted effective stiffness tended to under estimate the experimental values. Average absolute errors in effective stiffness estimates ranged between 31 and 38% for the sampling procedure compared to a range 49-150% for a regression fit to volume fraction squared. Trabecula level stress ranged between -200 and +300 times that predicted by analyzing trabecular bone as a continuum. Both tensile and compressive tissue stresses were engendered by a continuum compressive stress. Trabecula level strain energy density (SED) ranged between 0 and 100 times the continuum SED value for two trabecular specimens. In conclusion, the homogenization sampling procedure consistently predicted the influence of trabecular bone architecture on effective stiffness. It can also provide trabecular tissue stress and strain estimates for arbitrary global loading of whole bones. Tissue stresses and strains showed large variations compared to corresponding continuum level quantities. PMID:8188724

Hollister, S J; Brennan, J M; Kikuchi, N

1994-04-01

333

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

334

Mercury in freshwater fish and clams from the Cerro Prieto geothermal field of Baja California, Mexico  

SciTech Connect

Several reports have expressed concern about the potential toxicity hazards and environmental contamination of mercury emissions from geothermal fields in Hawaii, New Zealand, Iceland, California and Mexico. Inorganic mercury discharged from the sources may accumulate in the sediments of rivers or lakes and, after microbiological methylation may become concentrated in the edible tissue of fish. This study involves assessment of geothermal mercury pollution arising from Cerro Prieto. For this purpose the fish Tilapia mossambica and the clam Corbicula fluminea were collected from the freshwater courses of the Mexicali Valley. Reports indicated that in 1982, 13 t of T. mossambica were destinated for human consumption. A further aim was to provide base line data and information relevant to the level of mercury contamination for the Mexicali Valley.

Gutierrez-Galindo, E.A.; Munoz, G.F.; Flores, A.A.

1988-08-01

335

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

336

Neurobehavioral changes in response to alterations in gene expression profiles in the brains of mice exposed to low and high levels of mercury vapor during postnatal development.  

PubMed

This study examined the relationship between neurobehavioral changes and alterations in gene expression profiles in the brains of mice exposed to different levels of Hg(0) during postnatal development. Neonatal mice were repeatedly exposed to mercury vapor (Hg(0)) at a concentration of 0.057 mg/m(3) (low level), which was close to the current threshold value (TLV), and 0.197 mg/m(3) (high level) for 24 hr until the 20(th) day postpartum. Behavioral responses were evaluated based on changes in locomotor activity in the open field test (OPF), learning ability in the passive avoidance response test (PA), and spatial learning ability in the Morris water maze (MM) at 12 weeks of age. No significant differences were observed in the three behavioral measurements between mice exposed to the low level of Hg(0) and control mice. On the other hand, total locomotive activity in mice exposed to the high level of Hg(0) was significantly decreased and central locomotion was reduced in the OPF task. Mercury concentrations were approximately 0.4 ?g/g and 1.9 ?g/g in the brains of mice exposed to the low and high levels of Hg(0), respectively. Genomic analysis revealed that the expression of 2 genes was up-regulated and 18 genes was down-regulated in the low-level exposure group, while the expression of 3 genes was up-regulated and 70 genes was down-regulated in the high-level exposure group. Similar alterations in the expression of seven genes, six down-regulated genes and one up-regulated gene, were observed in both groups. The results indicate that an increase in the number of altered genes in the brain may be involved in the emergence of neurobehavioral effects, which may be associated with the concentration of mercury in the brain. Moreover, some of the commonly altered genes following exposure to both concentrations of Hg(0) with and without neurobehavioral effects may be candidates as sensitive biomarker genes for assessing behavioral effects in the early stages of development. PMID:25056781

Yoshida, Minoru; Honda, Akiko; Watanabe, Chiho; Satoh, Masahiko; Yasutake, Akira

2014-08-01

337

Age-specific profiles of tissue-level composition and mechanical properties in murine cortical bone  

PubMed Central

There is growing evidence that bone composition and tissue-level mechanical properties are significant determinants of skeletal integrity. In the current study, Raman spectroscopy and nanoindentation testing were co-localized to analyze tissue-level compositional and mechanical properties in skeletally mature young (4 or 5 months) and old (19 months) murine femora at similar spatial scales. Standard multivariate linear regression analysis revealed age-dependent patterns in the relationships between mechanical and compositional properties at the tissue scale. However, changes in bone material properties with age are often complex and nonlinear, and can be missed with linear regression and correlation-based methods. A retrospective data mining approach was implemented using non-linear multidimensional visualization and classification to identify spectroscopic and nanoindentation metrics that best discriminated bone specimens of different age-classes. The ability to classify the specimens into the correct age group increased by using combinations of Raman and nanoindentation variables (86–96% accuracy) as compared to using individual measures (59–79% accuracy). Metrics that best classified 4 or 5 month and 19 month specimens (2-age classes) were mineral to matrix ratio, crystallinity, modulus and plasticity index. Metrics that best distinguished between 4, 5 and 19 month specimens (3-age classes) were mineral to matrix ratio, crystallinity, modulus, hardness, cross-linking, carbonate to phosphate ratio, creep displacement and creep viscosity. These findings attest to the complexity of mechanisms underlying bone tissue properties and draw attention to the importance of considering non-linear interactions between tissue-level composition and mechanics that may work together to influence material properties with age. The results demonstrate that a few non-linearly combined compositional and mechanical metrics provide better discriminatory information than a single metric or a single technique. PMID:22285889

Raghavan, Mekhala; Sahar, Nadder D.; Kohn, David H.; Morris, Michael D.

2012-01-01

338

Combined multi-gene analysis at the RNA and protein levels in single FFPE tissue sections.  

PubMed

Novel approaches of individualized medicine require rapid analyses of comprehensive multi-gene expression patterns both at the RNA and protein levels. Optimally these analyses are achieved with minimal amounts of tissues, which are derived from routine procedures of clinical diagnostics. We demonstrate the parallel analyses of gene expression of six different genes at the RNA and protein levels in two consecutive sections of routinely processed FFPE tissues. This was achieved by combination of multi-epitope-ligand cartography (MELC) and fully automatically magnetic bead-based RNA extraction and subsequent qRT-PCR analysis. Our work provides proof-of-principle that comprehensive analyses of multi-gene expression patterns can be achieved by the combination of these two high content technologies. This may provide new perspectives for the determination of pathogenic gene expression in the framework of individualized medicine. PMID:23583336

Ostalecki, Christian; Konrad, Andreas; Thurau, Elisabeth; Schuler, Gerold; Croner, Roland S; Pommer, Ansgar J; ael Stürzl, Mich

2013-08-01

339

Elevated mitochondrial cisplatin-DNA adduct levels in rat tissues after transplacental cisplatin exposure.  

PubMed

Although there is evidence that the toxic effects of cis-diamminedichloroplatinum(II) (cisplatin) include morphologically abnormal mitochondria, direct demonstrations of mitochondrial DNA damage by this chemotherapeutic agent have rarely been reported. Here we show that, in rats exposed to a single dose of cisplatin during gestation, cisplatin-DNA binding levels in both maternal and fetal liver and brain mitochondrial DNA are higher than those observed in genomic DNA. Pregnant F344/NCr rats were injected i.p. with either 5 or 15 mg cisplatin/kg body wt at 18 days of gestation and killed 24 h later. Cisplatin-DNA adducts were determined by dissociation-enhanced lanthanide fluoroimmunoassay using a cisplatin-DNA standard modified in the same range as the biological samples. Values for genomic cisplatin-DNA adducts in multiple maternal and fetal tissues have been presented elsewhere. Here, genomic DNA adduct levels for liver, brain, kidney and placenta are reported again for comparison with mitochondrial DNA adduct levels in the same tissues. In maternal and fetal brain, mitochondrial DNA adduct levels were approximately 7- to 50-fold higher than genomic DNA adduct levels, and in fetal liver they were approximately 2- to 16-fold higher than genomic DNA adduct levels. These studies demonstrate extensive cisplatin-DNA adduct formation in brain and liver mitochondria of fetal rats exposed transplacentally and suggest that mitochondrial DNA in some organs may be a particular target for cisplatin genotoxicity. PMID:9054594

Giurgiovich, A J; Diwan, B A; Olivero, O A; Anderson, L M; Rice, J M; Poirier, M C

1997-01-01

340

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

341

Mercury in sediment and fish from North Mississippi Lakes.  

PubMed

Sediments and/or fish were collected from Sardis, Enid and Grenada Lakes, which are located in three different watersheds in North Mississippi, in order to assess mercury contamination. The mean total mercury concentration in sediments from Enid Lake in 1997 was 0.154 mg Hg/kg, while 1998 sediment concentrations in Sardis, Enid and Grenada Lakes were 0.112, 0.088 and 0.133 mg Hg/kg, respectively. Sediment mercury concentrations in 1999 were similar in all three lakes but, generally lower than 1998. Mean total mercury concentrations in edible fillets of fish collected from Enid Lake in 1998 were above the human health FDA action level (> 1.0 mg Hg/kg) for bass (1.40), crappie (1.69) and gar (1.89); however, tissue concentrations were less than 1.0 mg Hg/kg in carp (0.63) and catfish (0.82). Human hazard indexes for each species was > or = 1 for both adults and children, indicating that there is a potential for toxic effects to occur. In addition, calculated consumption limits indicate that adults may consume 4-12 oz. of fish per month, depending on the species consumed. For children, 2 oz. per month may be consumed. Further studies are needed to determine the exact environmental consequences and human health impacts associated with mercury contamination in North Mississippi and the Southeastern United States. PMID:11272915

Huggett, D B; Steevens, J A; Allgood, J C; Lutken, C B; Grace, C A; Benson, W H

2001-03-01

342

Levels of non-essential elements in muscle from harp seal (Phagophilus groenlandicus) and hooded seal (Cystophora cristata) caught in the Greenland Sea area.  

PubMed

The non-essential elements, arsenic, cadmium, mercury and lead, inevitably accumulate in marine top predators such as seals. The concentration of these elements and the essential element selenium, due to its proposed protective properties against mercury toxicity in marine mammals, were measured in muscle, liver and kidney from reproductive active females of harp seal (Phagophilus groenlandicus) and hooded seal (Cystophora cristata) caught in the drift ice between Iceland and East Greenland. Arsenic levels were below 1 microg/g w.w. in all analysed samples, and were therefore low compared to other seafood products. The concentrations of arsenic found in the present study were comparable to the results reported in a similar study from 1985. Mean concentrations of total mercury in muscle from the present study were higher than levels in other seafood products. The levels of total mercury from the present study showed a tendency of lower levels in all tissue samples compared to the study from 1985. Methyl mercury displayed a trend of a lower ratio of methyl mercury to total mercury as the concentration of total mercury increased, indicating a demethylation of methyl mercury at high total mercury concentrations (e.g. mercury in liver of hooded seal). The concentration ratio of methyl mercury to total mercury in muscle samples was more than 75%, with total mercury concentration less than 0.5 microg/g w.w., whereas the ratio for liver was as low as 0.2% with a total mercury concentration of 128 microg/g w.w. The molar concentration ratios of selenium to mercury showed that selenium was present in a molar surplus to mercury in all tissues with low mercury concentration. However, there seemed to be a general mobilisation of selenium in liver and kidney tissues of harp seal and hooded seal, whereas an extraordinary mobilisation seemed to take place at hepatic mercury concentrations exceeding 50 microg/g w.w. The mean concentrations of lead in muscles in the present study were higher than in fish and other seafood products from the Barents Sea. The lead concentrations from the present study were lower than levels reported in the 1985 study. However, the levels of the non-essential elements analysed in muscle from the two seal species in the present study should not prevent the use of seal meat in human nutrition. PMID:16368127

Brunborg, Linn Anne; Graff, Ingvild Eide; Frøyland, Livar; Julshamn, Kåre

2006-08-01

343

Food chain transfer and potential renal toxicity of mercury to small mammals at a contaminated terrestrial field site.  

PubMed

Mercury concentrations were determined in surface soil and biota at a contaminated terrestrial field site and were used to calculate transfer coefficients of mercury through various compartments of the ecosystem based on trophic relationships. Mercury concentrations in all compartments (soil, vegetation, invertebrates, and small mammals) were higher than mercury concentrations in corresponding samples at local reference sites. Nonetheless, mercury concentrations in biota did not exceed concentrations in the contaminated surface soil, which averaged 269 ?g g(-1). Plant tissue concentrations of mercury were low (0.01 to 2.0 ?g g(-1)) and yielded soil to plant transfer coefficients ranging from 3.7×10(-5) for seeds to 7.0×10(-3) for grass blades. Mercury concentrations in invertebrates ranged from 0.79 for harvestmen (Phalangida) to 15.5 ?g g(-1) for undepurated earthworms (Oligochaeta). Mean food chain transfer coefficients for invertebrates were 0.88 for herbivores/omnivores and 2.35 for carnivores. Mean mercury concentrations in target tissue (kidney) were 1.16±1.16 ?g g(-1) for the white-footed mouse (Peromyscus leucopus), a granivore, and 38.8±24.6 ?g g(-1) for the shorttail shrew (Blarina brevicauda), an insectivore. Transfer coefficients for diet to kidney were 0.75 and 4.40 for P. leucopus and B. brevicauda, respectively. A comparison of kidney mercury residues measured in this study with values from controlled laboratory feeding studies from the literature indicate that B. brevicauda but not P. leucopus may be ingesting mercury at levels that are nephrotoxic. PMID:24201735

Talmage, S S; Walton, B T

1993-12-01

344

Mercury toxicity and the protective role of selenium in eel, Anguilla anguilla.  

PubMed

The aim of the study was to determine the impact trace metals, mainly toxic ones, on the condition of eel (Anguilla anguilla) inhabiting four regions of Poland. Metal concentrations in eel muscle tissues were studied as functions of size, region, and season 2011-2012. The levels of metals were also used for risk assessment on consumer health. Copper and zinc occurred at concentrations that could only have positive impacts on eel condition. Low levels of cadmium and lead did not impair the condition of the fish. However, mercury occurred at high levels and increased with fish length and season. The mercury levels in eels were compared with the threshold of toxicity (500-1,200 ?g kg(-1)), which can cause changes in biochemical processes and impair fish reproduction. The concentration of mercury was 1,010 ?g kg(-1) in one specimen of the 120 samples examined, and in 16 specimens, it exceeded 500 ?g kg(-1). The toxic effects of the mercury could have been attenuated by the selenium in the muscles of the eel, especially in the muscles of smaller specimens in which the Se/Hg molar ratio was higher than 1 with a positive correlation between these two elements. In larger specimens measuring in excess of 70 cm, this coefficient was below 1, and the mercury to selenium correlation was negative, which meant that the protective effects of selenium were weaker. The mercury in the muscles of large specimens at levels exceeding 500 ?g kg(-1) could have weakened eel condition and also posed a threat to consumer health. The cadmium and lead in the muscles of the eel did not affect the condition of the fish. Mercury weakened the condition of large eel, A. anguilla. Selenium protected small- and medium-sized eel against the toxic effects of mercury. PMID:25099659

Polak-Juszczak, Lucyna; Robak, Stanis?aw

2015-01-01

345

The Relation between Plasma Tissue Factor and Oxidized LDL Levels in Acute Coronary Syndromes  

Microsoft Academic Search

Aim: Tissue factor (TF) is a low-molecular-weight glycoprotein responsible for the initiation of the coagulation cascade. The relation between oxidized low-density lipoprotein (Ox-LDL), that has been shown to be involved in atherogenesis, and TF has not been evaluated before in circulating plasma. The aim of this study was to determine plasma levels of TF and Ox-LDL in acute coronary syndrome

Ebru Emekli-Alturfan; Isik Basar; A. Ata Alturfan; Faruk Ayan; Lale Koldas; Huriye Balci; Nesrin Emekli

2010-01-01

346

Amitriptyline enhances extracellular tissue levels of adenosine in the rat hindpaw and inhibits adenosine uptake.  

PubMed

Local administration of amitriptyline into the rat hindpaw produces peripheral antinociception; this is reduced by adenosine receptor antagonists and appears to involve endogenous adenosine. The present study used peripheral microdialysis: (a) to determine whether amitriptyline could enhance extracellular tissue levels of endogenous adenosine in the rat hindpaw and (b) to examine mechanisms by which such an increase could occur. Local injection of amitriptyline into the plantar hindpaw, at doses that produce peripheral antinociception (100-300 nmol), produced an increase in local extracellular levels of adenosine. When injected in combination with formalin, which also enhances such levels of adenosine, an additive increase was observed. This adenosine originated partly as nucleotide, as inhibition of ecto-5'-nucleotidase reduced the amount of adenosine detected in the probe following administration of amitriptyline. When administered in combination with exogenous adenosine, amitriptyline augmented recovery of adenosine in the probe. Pretreatment of rats with capsaicin augmented the ability of amitriptyline to increase adenosine levels detected in the dialysis probe; it also enhanced tissue recovery of exogenously administered adenosine. In uptake studies using cultured rat C6 glioma cells, amitriptyline inhibited adenosine uptake by an adenosine transporter (IC50 0.37 +/- 0.12 mM). In enzyme assays, amitriptyline had no effect on adenosine kinase or adenosine deaminase activity. These results demonstrate that amitriptyline: (a) enhances extracellular tissue levels of adenosine in the rat hindpaw following local administration in vivo and (b) inhibits adenosine uptake but has no effect on metabolism in vitro. Therefore, increased extracellular adenosine levels in vivo appear to result partially from extracellular conversion of nucleotide and partially from inhibition of uptake. PMID:16156010

Sawynok, Jana; Reid, Allison R; Liu, Xue Jun; Parkinson, Fiona E

2005-08-22

347

Mercury and cadmium uptake from seawater and from food by the Norway lobster Nephrops norvegicus  

SciTech Connect

Norway lobsters, nephrops norvegicus, were fed on a mercury- and cadmium-rich diet for up to 50 d or were exposed to sublethal concentrations of organic mercury, inorganic mercury, or cadmium in seawater for 30 d. Cadmium taken up from seawater accumulated mainly in the hepatopancreas and gill, while it accumulated mainly in the hepatopancreas after feeding. Both organic and inorganic mercury taken up from seawater accumulated mainly in the gill, while highest concentrations were found in the hepatopancreas after the feeding experiment. Accumulation of organic mercury was higher than that of inorganic mercury. Although all treatments resulted in the accumulation of mercury and cadmium from seawater and food, tissue distribution of metals differed significantly among treatments. Distributions of organic and inorganic mercury also varied among tissues after uptake from seawater, with organic mercury being more evenly distributed among tissues than inorganic mercury, the latter being found predominantly in the gill.

Canli, M.; Furness, R.W. [Univ. of Glasgow (United Kingdom). Div. of Environmental and Evolutionary Biology

1995-05-01

348

Local Mechanical Stimuli Regulate Bone Formation and Resorption in Mice at the Tissue Level  

PubMed Central

Bone is able to react to changing mechanical demands by adapting its internal microstructure through bone forming and resorbing cells. This process is called bone modeling and remodeling. It is evident that changes in mechanical demands at the organ level must be interpreted at the tissue level where bone (re)modeling takes place. Although assumed for a long time, the relationship between the locations of bone formation and resorption and the local mechanical environment is still under debate. The lack of suitable imaging modalities for measuring bone formation and resorption in vivo has made it difficult to assess the mechanoregulation of bone three-dimensionally by experiment. Using in vivo micro-computed tomography and high resolution finite element analysis in living mice, we show that bone formation most likely occurs at sites of high local mechanical strain (p<0.0001) and resorption at sites of low local mechanical strain (p<0.0001). Furthermore, the probability of bone resorption decreases exponentially with increasing mechanical stimulus (R2?=?0.99) whereas the probability of bone formation follows an exponential growth function to a maximum value (R2?=?0.99). Moreover, resorption is more strictly controlled than formation in loaded animals, and ovariectomy increases the amount of non-targeted resorption. Our experimental assessment of mechanoregulation at the tissue level does not show any evidence of a lazy zone and suggests that around 80% of all (re)modeling can be linked to the mechanical micro-environment. These findings disclose how mechanical stimuli at the tissue level contribute to the regulation of bone adaptation at the organ level. PMID:23637993

Schulte, Friederike A.; Ruffoni, Davide; Lambers, Floor M.; Christen, David; Webster, Duncan J.; Kuhn, Gisela; Müller, Ralph

2013-01-01

349

Volcanic mercury in Pinus canariensis  

NASA Astrophysics Data System (ADS)

Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 ?g kg-1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 ?g kg-1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 ?g kg-1) and bark (6.0 ?g kg-1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.

Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis

2013-08-01

350

Volcanic mercury in Pinus canariensis.  

PubMed

Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 ?g kg(-1)) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 ?g kg(-1)). Thus, mercury emissions originating from the eruption remained only as a mark-in pyroclastic wounds-and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 ?g kg(-1)) and bark (6.0 ?g kg(-1)) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species. PMID:23760570

Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis

2013-08-01

351

Thyroid of lake sturgeon, Acipenser fulvescens. I. Hormone levels in blood and tissues.  

PubMed

The authors measured thyroid hormone (TH) levels in plasma, whole carcass, and tissues of cultured 2-year-old immature lake sturgeon held in fresh water and in serum of adults at spawning time from the Winnipeg River. Circulating thyroxine (T4) and 3,5,3'-triiodothyronine (T3) levels were low (T4 approximately 0.3 ng/ml, T3 approximately 0.2 ng/ml) in all cultured fish and most adults, but a few of the latter had exceptionally high T4 and T3 levels. The percentages of blood TH found in erythrocytes were 19.5% (T4), 6.1% (T3) and 6.9% (reverse T3 = rT3). Equilibrium dialysis showed much higher percentages of plasma free (F) FT4 (1.1%), FT3 (0.4%), and FrT3 (3,3',5'-triiodothyronine = rT3, 3.0%) for sturgeon than for rainbow trout, indicating more limited TH binding to sturgeon plasma sites. However, concentrations of FT4 and FT3 were close to those reported for salmonids. T3 levels exceeded T4 levels in most extrathyroidal tissues of cultured sturgeon but in most cases were less than 0.1 ng/g and 10 to 100 times lower than reported for salmonids; only the whole brain T3 concentration (5.6 ng/g) approached that of salmonids. The digested thyroid contained 21.3 ng T3/g and 2.4 ng T4/g. The authors conclude that lake sturgeon have a low circulating reserve of bound TH but have FT4 and FT3 concentrations close to those of salmonids. The high thyroidal T3:T4 ratio and low tissue T4 levels suggest that, in contrast to teleosts studied to date, the thyroid may be a significant direct source of T3, the primary TH in sturgeon tissues. High serum T4 and T3 levels in some sturgeon at spawning time may suggest a thyroid role in reproduction. PMID:11825034

Plohman, James C; Dick, Terry A; Eales, J Geoffrey

2002-01-01

352

Selenium inhibits the phytotoxicity of mercury in garlic (Allium sativum)  

SciTech Connect

To investigate the influence of selenium on mercury phytotoxicity, the levels of selenium and mercury were analyzed with inductively coupled plasma-mass spectrometry (ICP-MS) in garlic tissues upon exposure to different dosages of inorganic mercury (Hg{sup 2+}) and selenite (SeO{sub 3}{sup 2?}) or selenate (SeO{sub 4}{sup 2?}). The distributions of selenium and mercury were examined with micro-synchrotron radiation X-ray fluorescence (?-SRXRF), and the mercury speciation was investigated with micro-X-ray absorption near edge structure (?-XANES). The results show that Se at higher exposure levels (>1 mg/L of SeO{sub 3}{sup 2?} or SeO{sub 4}{sup 2?}) would significantly inhibit the absorption and transportation of Hg when Hg{sup 2+} levels are higher than 1 mg/L in culture media. SeO{sub 3}{sup 2?} and SeO{sub 4}{sup 2?} were found to be equally effective in reducing Hg accumulation in garlic. The inhibition of Hg uptake by Se correlates well with the influence of Se on Hg phytotoxicity as indicated by the growth inhibition factor. Elemental imaging using ?-SRXRF also shows that Se could inhibit the accumulation and translocation of Hg in garlic. ?-XANES analysis shows that Hg is mainly present in the forms of Hg–S bonding as Hg(GSH){sub 2} and Hg(Met){sub 2}. Se exposure elicited decrease of Hg–S bonding in the form of Hg(GSH){sub 2}, together with Se-mediated alteration of Hg absorption, transportation and accumulation, may account for attenuated Hg phytotoxicity by Se in garlic. -- Highlights: ? Hg phytotoxicity can be mitigated by Se supplement in garlic growth. ? Se can inhibit the accumulation and transportation of Hg in garlic tissues. ? Localization and speciation of Hg in garlic can be modified by Se.

Zhao, Jiating [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Gao, Yuxi, E-mail: gaoyx@ihep.ac.cn [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Yu-Feng; Hu, Yi; Peng, Xiaomin [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Dong, Yuanxing [Department of Physics, Xinzhou Teachers University, Xinzhou 034000 (China)] [Department of Physics, Xinzhou Teachers University, Xinzhou 034000 (China); Li, Bai; Chen, Chunying [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chai, Zhifang, E-mail: chaizf@ihep.ac.cn [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2013-08-15

353

Mercury in the Anthropocene Ocean  

E-print Network

The toxic metal mercury is present only at trace levels in the ocean, but it accumulates in fish at concentrations high enough to pose a threat to human and environmental health. Human activity has dramatically altered the ...

Lamborg, Carl

354

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

355

Human Exposure and Health Effects of Inorganic and Elemental Mercury  

PubMed Central

Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety. PMID:23230464

Zheng, Wei

2012-01-01

356

Mercury in Nelson’s Sparrow Subspecies at Breeding Sites  

E-print Network

Background: Mercury is a persistent, biomagnifying contaminant that can cause negative effects on ecosystems. Marshes are often areas of relatively high mercury methylation and bioaccumulation. Nelson’s Sparrows (Ammodramus nelsoni) use marsh habitats year-round and have been documented to exhibit tissue mercury concentrations that exceed negative effects thresholds. We sought to further characterize the potential risk of Nelson’s Sparrows to mercury exposure by sampling individuals from sites within the range of each of its subspecies.

Virginia L Winder; Steven D. Emslie

2012-01-01

357

The effects of low-level radiofrequency and microwave radiation on brain tissue and animal behaviour.  

PubMed

There has been much public interest and controversy about the effects of exposure to low levels of microwave and radiofrequency radiation. Of particular interest are reports of radiation-induced changes in brain tissue and animal behaviour. This review considers the evidence supporting some of these effects. The main conclusions of the review are: The levels of tracer substances in the brain tissue of conscious or anaesthetized animals can be altered by acute exposure to microwave radiation that is sufficient to raise the brain temperature by several degrees Celsius. However, the results of such experiments are difficult to interpret, being in some cases contradictory or influenced by various confounding factors, and the data cannot be considered sufficient to recommend a threshold for human tolerance. The evidence that calcium ion exchange in living nervous tissues is affected by amplitude-modulated radiofrequency and microwave radiation is inconclusive. Exposure sufficient to cause an increase in core temperature of about 1 degree C, corresponding to specific energy absorption rates of about 2-8 W kg-1 may adversely affect animal behaviour. PMID:3533816

Blackwell, R P; Saunders, R D

1986-11-01

358

Got Mercury?  

NASA Technical Reports Server (NTRS)

Many lamps used in various spacecraft contain elemental mercury, which is efficiently absorbed through the lungs as a vapor. The liquid metal vaporizes slowly at room temperature, but may be completely vaporized when lamps are operating. Because current spacecraft environmental control systems are unable to remove mercury vapors, we considered short-term and long-term exposures. Using an existing study, we estimated mercury vapor releases from lamps that are not in operation during missions lasting less than or equal to 30 days; whereas we conservatively assumed complete vaporization from lamps that are operating or being used during missions lasing more than 30 days. Based on mercury toxicity, the Johnson Space Center's Toxicology Group recommends stringent safety controls and verifications for any hardware containing elemental mercury that could yield airborne mercury vapor concentrations greater than 0.1 mg/m3 in the total spacecraft atmosphere for exposures lasting less than or equal to 30 days, or concentrations greater than 0.01 mg/m3 for exposures lasting more than 30 days.

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

2010-01-01

359

Bothrops jararaca Venom Metalloproteinases Are Essential for Coagulopathy and Increase Plasma Tissue Factor Levels during Envenomation  

PubMed Central

Background/Aims Bleeding tendency, coagulopathy and platelet disorders are recurrent manifestations in snakebites occurring worldwide. We reasoned that by damaging tissues and/or activating cells at the site of the bite and systemically, snake venom toxins might release or decrypt tissue factor (TF), resulting in activation of blood coagulation and aggravation of the bleeding tendency. Thus, we addressed (a) whether TF and protein disulfide isomerase (PDI), an oxireductase involved in TF encryption/decryption, were altered in experimental snake envenomation; (b) the involvement and significance of snake venom metalloproteinases (SVMP) and serine proteinases (SVSP) to hemostatic disturbances. Methods/Principal Findings Crude Bothrops jararaca venom (BjV) was preincubated with Na2-EDTA or AEBSF, which are inhibitors of SVMP and SVSP, respectively, and injected subcutaneously or intravenously into rats to analyze the contribution of local lesion to the development of hemostatic disturbances. Samples of blood, lung and skin were collected and analyzed at 3 and 6 h. Platelet counts were markedly diminished in rats, and neither Na2-EDTA nor AEBSF could effectively abrogate this fall. However, Na2-EDTA markedly reduced plasma fibrinogen consumption and hemorrhage at the site of BjV inoculation. Na2-EDTA also abolished the marked elevation in TF levels in plasma at 3 and 6 h, by both administration routes. Moreover, increased TF activity was also noticed in lung and skin tissue samples at 6 h. However, factor VII levels did not decrease over time. PDI expression in skin was normal at 3 h, and downregulated at 6 h in all groups treated with BjV. Conclusions SVMP induce coagulopathy, hemorrhage and increased TF levels in plasma, but neither SVMP nor SVSP are directly involved in thrombocytopenia. High levels of TF in plasma and TF decryption occur during snake envenomation, like true disseminated intravascular coagulation syndrome, and might be implicated in engendering bleeding manifestations in severely-envenomed patients. PMID:24831016

Yamashita, Karine M.; Alves, André F.; Barbaro, Katia C.; Santoro, Marcelo L.

2014-01-01

360

Neuropsychological assessment at school-age and prenatal low-level exposure to mercury through fish consumption in an Italian birth cohort living near a contaminated site.  

PubMed

The relative effects of prenatal and postnatal low-level mercury exposure and fish intake on child neurodevelopment are still controversial. Limited evidence is available from Mediterranean populations. In this prospective study, we measured the Verbal and Performance IQ in Italian children at school-age who were resident in an area declared as a National contaminated site because of mercury pollution, taking into account the possible beneficial effect of fish consumption and potential confounders. A mother-child cohort made up of 242 children was established at birth in Northeastern Italy in 2001. Their mothers were interviewed approximately 2 months after delivery to determine type, quantity, and origin of fish consumed during pregnancy and about a number of mother, child and family characteristics. Total mercury (THg) and methyl mercury (MeHg) were assessed in maternal hair and breast milk and in the child's hair. When children reached 7-9 years of age, 154 (63.6%) parents gave consent to participate in a follow-up evaluation. On that occasion, a child's hair sample was collected to determine the current concentration of THg, mothers were asked to complete a self-administered questionnaire, and children underwent neuropsychological testing. Verbal IQ, performance IQ and full scale IQ were measured by the Wechsler Intelligence Scale for Children (WISC III) administered by psychologists at school or local health centers. Demographic, socioeconomic and lifestyle information, medical information of the child's family and the child's dietary habits were collected using a questionnaire filled in by mothers. Multivariable linear regression models were used to evaluate the association between prenatal THg exposure through fish consumption of mothers in pregnancy and children's IQ after adjustment for possible confounders such as fish consumption of mothers in pregnancy, child's fish consumption at follow-up, child's birthweight, maternal cigarette smoking during pregnancy, house size and property place of residence during pregnancy and gender. THg in the child's hair at 7 years of age was fairly correlated with THg in maternal hair at delivery (rs=0.35; p<0.0001) and was strongly correlated with child's seafood consumption (rs=0.50, p<0.0001). No differences in maternal THg levels were found when comparing children with low or extremely low or high or extremely high scores vs others, considering separately full scale, verbal, and performance IQs. Children born from mothers with hair THg levels greater than or equal to 2000ng/g had full scale, verbal and performance IQs which were 4-5 points lower than children born from women with lower THg levels, but these differences were not statistically significant. Fresh fish intake of mothers in pregnancy was slightly positively associated with full scale and performance but not so with verbal IQs. Canned fish showed to be negatively associated with all the outcome variables. Unexpectedly, children born to mothers from one town showed IQ scores significantly lower than the other children; however, none of the many variables considered in these analyses could explain this result. The relatively low Hg levels found in the biological samples did not provide evidence of high and extensive Hg exposure in this population. Although THg levels in maternal and child's biological samples are correlated with fish consumption, the effects of THg and fish on neurological outcomes go in opposite directions. These results do not allow to develop recommendations regarding fish consumption in pregnancy but suggest that keeping THg hair levels<2000ng/g might be desirable. PMID:23523155

Deroma, L; Parpinel, M; Tognin, V; Channoufi, L; Tratnik, J; Horvat, M; Valent, F; Barbone, F

2013-07-01

361

CALORIE RESTRICTION MODIFIES UBIQUINONE AND COQ TRANSCRIPTS LEVELS IN MOUSE TISSUES  

PubMed Central

We studied ubiquinone (Q), Q homologue ratio and steady-state levels of mCOQ transcripts in tissues from mice fed ad libitum or under calorie restriction. Maximum ubiquinone levels on a protein basis were found in kidney and heart, followed by liver, brain and skeletal muscle. Liver and skeletal muscle showed the highest Q9/Q10 ratios with significant inter-individual variability. Heart, kidney, and particularly brain exhibited lower Q9/Q10 ratios and inter-individual variability. In skeletal muscle and heart, the most abundant mCOQ transcript was mCOQ7, followed by mCOQ8, mCOQ2, mPDSS2, mPDSS1 and mCOQ3. In non muscular tissues (liver, kidney and brain) the most abundant mCOQ transcript was mCOQ2, followed by mCOQ7, mCOQ8, mPDSS1, mPDSS2, and mCOQ3. Calorie restriction increased both ubiquinone homologues and mPDSS2 mRNA in skeletal muscle, but mCOQ7 was decreased. In contrast, Q9 and most mCOQ transcripts were decreased in heart. Calorie restriction also modified Q9/Q10 ratio, which was increased in kidney and decreased in heart without alterations of mPDSS1 or mPDSS2 transcripts. We demonstrate for the first time that unique patterns of mCOQ transcripts exist in muscular and non-muscular tissues, and that Q and COQ genes are targets of calorie restriction in a tissue-specific way. PMID:21447381

Parrado, Cristina; López-Lluch, Guillermo; Rodríguez-Bies, Elisabet; Santa-Cruz, Sara; Navas, Plácido; Ramsey, Jon J.; Villalba, José M.

2011-01-01

362

Mercury in fish tissue of Idaho lakes vs. those of the Northeastern United States as it relates to the moderating effects of selenium  

EPA Science Inventory

The primary methyl-mercury (MeHg) exposure mode to wildlife and humans is through the consumption of aquatic organisms, particulary fish. Selenium has been demonstrated to moderate the toxicity of MeHg in every test animal type examined to date. A molar ratio of Se:Hg >1 appear...

363

Effects of selenium, cadmium, mercury, tellurium, arsenic, silver and cobalt on white muscle disease in lambs and effect of dietary forms of arsenic on its accumulation in tissues  

Microsoft Academic Search

The effects of feeding low selenium diets containing additions of cadmium (1 ppm), mercury (0.5 ppm), tellurium (2 ppm), arsenic (1 and 5 ppm), silver (50 ppm), or cobalt (25 ppm) to pregnant ewes on the development of white muscle disease (WMD) in their lambs were investigated. Some ewes were injected with selenium to serve as positive controls. The inclusion

P. D. Whanger; P. H. Weswig; J. A. Schmitz; J. E. Oldfield

1976-01-01

364

CD44 affects the expression level of FOS?like antigen 1 in cervical cancer tissues.  

PubMed

Cervical carcinoma is the second most prevalent type of malignancy in females worldwide. The crucial etiological factors involved in the development of cervical carcinoma include infection with the papillomavirus, and the structural or functional mutation of oncogenes and tumor suppressor genes. CD44 refers to a multifunctional family of type I transmembrane proteins. These proteins have been implicated in numerous biological processes, including cell adhesion, cell migration and metastasis. The present study examined the differences in the expression levels of ATP-binding cassette sub-family G member 2, CD24, CD44, CD133, cytokeratin (CK) 14 and CK19 between cervical cancer tissues and corresponding normal non-tumor tissues by flow cytometry. Then, the CD44+ or CD44? cells from cervical cancer tissues were sorted for identification and confirmation of differential expression by flow cytometry. The results demonstrated that the expression level of CD44 in cervical cancer tissues was higher than in the corresponding non-tumor normal tissues (t=3.12; P=0.0102). Compared with the CD44? cells, the FOS-like antigen 1 (Fra-1), nestin, nuclear receptor subfamily 4, group A, member 2, OCT4 and p63 genes were highly expressed in CD44+ cells. The fold changes were 3.55, 3.55, 2.46, 2.87 and 2.56, respectively (P<0.05). However, BMI1 polycomb ring finger oncogene, ck5, tumor protein p53 and lactotransferrin genes exhibited low expression levels in CD44+ cells. It was verified by western blot analysis and flow cytometry that Fra-1 was highly expressed in CD44+ cells. Fra-1 was a potential target of miR-19a and miR-19b. The expression of miR-19a and miR-19b was downregulated by ~50% in CD44+ cells compared with CD44? cells. These findings suggested that CD44 dysregulated the activation of the Fra?1 gene. The interaction of Fra-1 and CD44 may therefore be important in cervical carcinoma. PMID:24604526

Xiao, Songshu; Zhou, Yanhong; Jiang, Jianfa; Yuan, Le; Xue, Min

2014-05-01

365

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

366

Light induced changes in quinolone levels in rat serum and tissues.  

PubMed

Circadian rhythm may induce alterations of the pharmacokinetic properties of several drugs in clinical use. The aim of the study was to investigate whether lighting conditions alter the quinolone (pefloxacin) levels in serum and tissues and to determine any accumulation of the drug in the skin. Thirty male Wistar rats were divided into groups A, B, C, (n=10). The animals of group A were housed under 12h light/12h dark conditions, group B under 24h UV and group C was kept in complete darkness. All animals received 5 doses of 11mg/Kg pefloxacin every 8h for 48h.Pefloxacin levels were determined in serum, skin and femur by the inhibition zone in E.coli. in vitro. Pefloxacin concentrations in serum were increased in 24h darkness living status and decreased in 24h UV conditions as compared to group A animals. Additionally, both skin and femur pefloxacin levels were decreased under dark and UV conditions. In conclusion total light as well as total dark exposure may lead to pefloxacin pharmacokinetic changes which may have implications in the effectiveness of the drug in tissues. PMID:15726883

Tesseromatis, C; Kotsiou, A; Mourouzis, C; Saranteas, Th; Potamianou, A; Vairactaris, E

2004-01-01

367

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

368

Polychlorinated biphenyl levels in the tissues of exposed and nonexposed humans.  

PubMed Central

Polychlorinated biphenyls (PCBs) are synthetic chemicals, manufactured in volume from about 1929 to the 1970s. Environmental contamination by PCBs has been documented in various substances, including human tissue. PCBs have been measured in human tissue by a variety of analytical methods. PCB levels have been reported as an approximation of total PCB content expressed in terms of a commercial mixture, by identification and quantification of chromatographic peaks, or by qualitative and quantitative characterization of specific congeners. Until recently, the coplanar mono-ortho- and di-ortho substituted PCBs, which are especially toxic and present in significant concentration in humans from industrial countries, had not been measured in human tissues. Examples of various types of commonly used analyses are presented in general population subjects and in persons who experienced special exposure. In this paper, the usefulness of PCB blood determinations following potential exposure is demonstrated, and their application in health studies is illustrated from a number of case studies. Coplanar PCB, mono-ortho-substituted and di-ortho-substituted PCB levels in human blood are presented and compared with polychlorinated dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in the U.S. population. Dioxin toxic equivalents for the two groups of chemicals are calculated and compared. It is found that mono-ortho-substituted and, to a lesser extent, coplanar PCBs, contribute substantially to dioxin toxic equivalents (TEq) in blood from U.S. adults. Because of substantial PCB contribution to dioxin toxic equivalents, total dioxinlike toxicity can only be determined if dioxins, dibenzofurans, and dioxinlike PCBs are measured.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8187704

Schecter, A; Stanley, J; Boggess, K; Masuda, Y; Mes, J; Wolff, M; Fürst, P; Fürst, C; Wilson-Yang, K; Chisholm, B

1994-01-01

369

Effects of Hypolimnetic Oxygenation on Mercury Cycling in Twin Lake, Washington  

NASA Astrophysics Data System (ADS)

The accumulation of mercury in freshwater aquatic food webs is a widespread health concern. Nearly one-third of US lakes have fish consumption advisories in place due to elevated concentrations of mercury in fish tissue. Mercury, primarily from fossil fuel combustion, is widely deposited across the landscape in the form of ionic mercury. The deposited ionic mercury can be transformed to toxic methylmercury by anaerobic bacteria in anoxic waters and sediments. Once produced, methylmercury is taken up by algae and seston, and then biomagnified up the aquatic food web with levels increasing in successive trophic levels. This presentation summarizes three years (2008-2010) of mercury monitoring at North and South Twin Lakes, moderately deep (maximum depth ~15 m) meso-eutrophic lakes located on the Colville Indian Reservation in eastern Washington State. The objective of the study was to evaluate spatial and temporal patterns of the total and methyl mercury in the water column and zooplankton before and after the implementation of hypolimnetic oxygenation in North Twin Lake in 2009. The working hypothesis was that maintenance of an oxic hypolimnion would repress methylmercury enrichment in bottom waters, and subsequent uptake into zooplankton. Initial results confirm that oxygenation repressed hypolimnetic enrichment of methylmercury. In 2008, prior to oxygenation, peak levels of methylmercury in anaerobic bottom waters of North and South Twin Lakes were 0.4-0.6 ng/L. In 2009 levels were less than 0.05 ng/L in oxygenated North Twin Lake, but were again elevated in anaerobic bottom waters of South Twin Lake. Interestingly, during a two-week oxygenation test in North Twin Lake in the fall of 2008, bottom waters exhibited a short-term and reversible loss of methylmercury that correlated with a decrease in dissolved iron and manganese. Regarding zooplankton, total mercury was higher in zooplankton from oxygenated North Twin Lake relative to non-oxygenated South Twin Lake, particularly late in the fall. Analytical work and data analysis is ongoing to measure methylmercury in zooplankton and normalize mercury levels in zooplankton to zooplankton density to account for the potential effects of biodilution. This study sheds light on the complex biogeochemistry and bioaccumulation of mercury in lakes and the effects of hypolimnetic oxygenation on methylmercury cycling in lake ecosystems. With few management options available to resource managers, and limited near-term improvements expected from source control efforts, applied research is needed to evaluate the effectiveness of in-lake management strategies, such as lake oxygenation, in repressing mercury accumulation in aquatic biota.

Beutel, M.; Dent, S.; Reed, B.; Moore, B.; Yonge, D.; Shallenberger, E.

2010-12-01

370

Increased levels of tetra-antennary N-linked glycan but not core fucosylation are associated with hepatocellular carcinoma tissue  

PubMed Central

Background Alterations in glycosylation have long been associated with the development of cancer. In the case of primary hepatocellular carcinoma (HCC), one alteration that has often been associated is increased amounts of fucose attached to the N-glycans of serum proteins secreted by the liver. Methods In an effort to determine the origin of this increased fucosylation, we have performed N-linked glycan analysis of HCC tissue, the surrounding non tumor tissue, and compared this to tissue from a non diseased adult liver. Results Surprisingly, no difference in the level of fucosylation was observed from the three donor groups, suggesting that the increased levels of fucosylation observed in serum of those with HCC is not the result of increased synthesis of fucosylated proteins in the cancer tissue. On the other hand, increased levels of a tetra-antennary glycan were observed in the HCC tissue as compared to the surrounding tissue or to the non diseased livers. Conclusions This represents, to our knowledge, one of the first reports associating increased levels of branching with the development of HCC. Impact The identification of increased levels of tetra-antennary glycan on liver tumor tissue, as opposed to adjacent or non diseased tissue may lead to improved detection of HCC. PMID:22490318

Mehta, Anand; Norton, Pamela; Liang, Hongyan; Comunale, Mary Ann; Wang, Mengjun; Rodemich-Betesh, Lucy; Koszycki, Alex; Noda, Katsuhisa; Miyoshi, Eiji; Block, Timothy

2012-01-01

371

Expression levels of serine/glycine metabolism-related proteins in triple negative breast cancer tissues.  

PubMed

To evaluate the expression levels of serine/glycine metabolism-related proteins (PHGDH, PSAT, PSPH, SHMT, and GLDC) in six different subtypes of triple negative breast cancer (TNBC) patients and gain insight into their implications. Formalin-fixed, paraffin-embedded tissues from 129 TNBC patients were assembled into tissue microarrays. Immunohistochemical staining was performed for serine/glycine metabolism-related proteins (PHGDH, PSAT, PSPH, SHMT, and GLDC) and surrogate immunohistochemical markers (CK5/6, EGFR, claudin 3, claudin 4, claudin 7, E-cadherin, STAT1, interleukin-8 [IL-8], AR, and GGT-1) for identifying the molecular subtype of TNBC. TNBC subtype classifications included the following: basal-like (CK5/6-positive and/or EGFR-positive), molecular apocrine (AR-positive and/or GGT-1-positive), claudin-low (claudin 3-, claudin 4-, claudin 7-negative and/or E-cadherin-negative), immune-related (IL-8-negative and stromal STAT1-positive), mixed (features from two or more of the four subtypes), and null (no features from any of the four subtypes). Tissues from basal marker-positive patients showed increased expression levels of tumoral PHGDH compared with those from basal marker-negative patients (p?=?0.029); lack of stromal SHMT1 expression was significantly correlated with T stage (p?=?0.016). Multivariate Cox analysis revealed that a lack of stromal SHMT1 expression was an independent prognostic factor for predicting a shorter disease-free survival period (hazard ratio 4.002, 95 % confidence interval [CI] 1.077-14.83, p?=?0.038); furthermore, a lack of tumoral PHGDH expression was predictive of a shorter overall survival rate (hazard ratio 3.053, 95 % CI 1.002-9.305, p?=?0.050). In conclusion, the most abundantly expressed serine/glycine metabolism-related protein in basal-like TNBC tissues was tumoral PHGDH, and expression levels of stromal SHMT1 and tumoral PHGDH were inversely correlated with clinical prognostic factors. Also, this study is the first to assess serine/glycine relationships at the protein level in regards to clinical outcomes. PMID:24390667

Noh, Songmi; Kim, Do Hee; Jung, Woo Hee; Koo, Ja Seung

2014-05-01

372

Mercury bioaccumulation in organisms from three Puerto Rican estuaries.  

PubMed

We analyzed mercury levels in shrimp (Palaemonetes sp.), Blue Crabs (Callinectes sp.), fish (Tarpon Megalops atlantica and Tilapia Tilapia mossambica), lizards (Ameiva exsul), Cattle Egret (Bubulcus ibis) and Moorhen (Gallinula chloropus) in three estuaries in Puerto Rico in 1988. There were no quantifiable concentrations greater than the method detection limit of mercury in shrimp, crabs and lizards from any site. Mercury levels were also below detection limits in Tilapia, except for specimens collected at Frontera Creek, allegedly contaminated with mercury. However, mercury levels ranged from 92-238 ?g/kg (wet weight) in Tarpon, a predaceous fish that feeds on smaller fish. Few of the birds had detectable levels of mercury. Our results indicate relatively low concentrations of mercury in biota collected in all of the three estuaries at most trophic levels, although 10 of 12 Tarpon fillet samples from Frontera had detectable mercury compared to 3 of 12 fillet samples for the other two lagoons. PMID:24226951

Burger, J; Cooper, K; Saliva, J; Gochfeld, D; Lipsky, D; Gochfeld, M

1992-09-01

373

Effects of a Low Level Laser on Periodontal Tissue in Hypofunctional Teeth  

PubMed Central

Malocclusions, such as an open bite and high canines, are often encountered in orthodontic practice. Teeth without occlusal stimuli are known as hypofunctional teeth, and numerous atrophic changes have been reported in the periodontal tissue, including reductions in blood vessels in the periodontal ligament (PDL), heavy root resorption, and reduced bone mineral density (BMD) in the alveolar bone. Low Level Laser (LLL) has been shown to have a positive effect on bone formation and the vasculature. Although the recovery of hypofunctional teeth remains unclear, LLL is expected to have a positive influence on periodontal tissue in occlusal hypofunction. The aim of the present study was to elucidate the relationship between LLL and periodontal tissue in occlusal hypofunction. Twenty-four male rats aged 5 weeks were randomly divided into control and hypofunctional groups. An anterior metal cap and bite plate were attached to the maxillary and mandibular incisors in the hypofunctional group to simulate occlusal hypofunction in the molars. LLL irradiation was applied to the maxillary first molar through the gingival sulcus in half of the rats. Rats were divided into four groups; control, control+LLL, hypofunctional, and hypofunctional+LLL. Exposure to LLL irradiation was performed for 3 minutes every other day for 2 weeks. Animals were examined by Micro-CT at 5 and 7 weeks and were subsequently sacrificed. Heads were resected and examined histologically and immunohistologically. The hypofunctional group had obvious stricture of the PDL. However, no significant differences were observed in the PDL and alveolar bone between the hypofunctional+LLL and the control groups. In addition, the expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF)-positive cells were higher in the hypofunctional + LLL group than in the hypofunctional group. These results indicated that LLL enhanced the production of bFGF and VEGF in the periodontal tissue of hypofunctional teeth. PMID:24927024

Hayashi, Hidetaka; Terao, Akiko; Kunimatsu, Ryo; Kawata, Toshitsugu

2014-01-01

374

Improved prediction of rat cortical bone mechanical behavior using composite beam theory to integrate tissue level properties.  

PubMed

Tissue level characteristics of bone can be measured by nanoindentation and microspectroscopy, but are challenging to translate to whole bone mechanical behavior in this hierarchically structured material. The current study calculated weighted section moduli from microCT attenuation values based on tissue level relationships (Z(lin,a) and Z(lin,b)) between mineralization and material properties to predict whole bone mechanical behavior. Z(lin,a) was determined using the equation of the best fit linear regression between indentation modulus from nanoindentation and mineral:matrix ratio from Raman spectroscopy. To better represent the modulus of unmineralized tissue, a second linear regression with the intercept fixed at 0 was used to calculate Z(lin,b). The predictive capability of the weighted section moduli calculated using a tissue level relationship was compared with average tissue level properties and weighted section moduli calculated using an apparent level relationship (Z(exp)) between Young's Modulus and mineralization. A range of bone mineralization was created using vitamin D deficiency in growing rats. After 10 weeks, left femurs were scanned using microCT and tested to failure in 3 point bending. Contralateral limbs were used for co-localized tissue level mechanical properties by nanoindentation and compositional measurements by Raman microspectroscopy. Vitamin D deficiency reduced whole bone stiffness and strength by ?35% and ?30%, respectively, but only reduced tissue mineral density by ?10% compared with Controls. Average tissue level properties did not correlate with whole bone mechanical behavior while Z(lin,a), Z(lin,b), and Z(exp) predicted 54%, 66%, and 80% of the failure moment respectively. This study demonstrated that in a model for varying mineralization, the composite beam model in this paper is an improved method to extrapolate tissue level data to macro-scale mechanical behavior. PMID:23021607

Kim, Grace; Boskey, Adele L; Baker, Shefford P; van der Meulen, Marjolein C H

2012-11-15

375

Mercury levels assessment in hair of riverside inhabitants of the Tapajós River, Pará State, Amazon, Brazil: Fish consumption as a possible route of exposure.  

PubMed

The study present evaluated the levels of mercury (Hg) and methylmercury (MeHg) in hair samples of people from Barreiras community, riverside inhabitants of the Tapajós River (Pará, Brazil), an area impacted by clandestine gold mining, as well as we analyzed the levels of Hg and Se (selenium) in nine fish species (carnivores and non-carnivorous) from the Tapajós River, which stand out as the main species consumed by riverside inhabitants, to evaluate a relationship between frequency of fish consumption and Hg concentration, and also to evaluate possible mechanisms of fish protection (or non-protection) to Hg exposure by Se. Furthermore we analyze the water quality to evaluate the environmental trophic state, fact responsible by creating conditions that can potentiate the effects of toxic mercury. Concentrations of Hg and MeHg were analyzed in hair samples of 141 volunteers in different age band. Of those, 84.40% of samples present values above the threshold for biological tolerance, which is 6.00?gg(-1) of total Hg in hair. Total Hg, in men there was a variation of 2.07-24.93?gg(-1), while for women the variation was 4.84-27.02?gg(-1). Consequently, the level of MeHg in men presented a variation of 1.49-19.57?gg(-1), with an average of 11.68?gg(-1), while with women the variation was from 3.73 to 22.35?gg(-1), with an average of 10.38?gg(-1). In fish species, Hg concentrations in carnivorous species had an average of 0.66?gg(-1), higher than that permitted by current legislation, ranging from 0.30 to 0.98?gg(-1), while the non-carnivorous species have values below the recommended by the legislation averaging 0.09?gg(-1), ranging between 0.02 and 0.44?gg(-1). For Se in fish, show that among carnivores, the contents of Se ranged between 0.18 and 0.54?gg(-1) with a mean of 0.34?gg(-1), while for non-carnivores these values were of the order of 0.16-0.56?gg(-1), with an average of 0.32?gg(-1). In surface water quality variables at the sampling points all showed values in accordance with the range established by current legislation. In this regard, the results provided by this study, while not conclusive, are strong indicators that despite not having been shown the relationship between the concentration of mercury in hair and feeding habits along the Tapajós River basin communities showed that a plausible correlation exists between levels of mercury and selenium in fish. This fact may serve as a subsidy to research human health, because in the Amazon, there is still a lot to examine with regards to the full understanding of the Se cycle. PMID:25467850

Faial, Kleber; Deus, Ricardo; Deus, Simonny; Neves, Ramiro; Jesus, Iracina; Santos, Elisabeth; Alves, Cláudio Nahum; Brasil, Davi

2014-11-11

376

Pairwise comparisons of ten porcine tissues identify differential transcriptional regulation at the gene, isoform, promoter and transcription start site level  

SciTech Connect

Highlights: •Transcriptome sequencing yielded 223 mill porcine RNA-seq reads, and 59,000 transcribed locations. •Establishment of unique transcription profiles for ten porcine tissues including four brain tissues. •Comparison of transcription profiles at gene, isoform, promoter and transcription start site level. •Highlights a high level of regulation of neuro-related genes at both gene, isoform, and TSS level. •Our results emphasize the pig as a valuable animal model with respect to human biological issues. -- Abstract: The transcriptome is the absolute set of transcripts in a tissue or cell at the time of sampling. In this study RNA-Seq is employed to enable the differential analysis of the transcriptome profile for ten porcine tissues in order to evaluate differences between the tissues at the gene and isoform expression level, together with an analysis of variation in transcription start sites, promoter usage, and splicing. Totally, 223 million RNA fragments were sequenced leading to the identification of 59,930 transcribed gene locations and 290,936 transcript variants using Cufflinks with similarity to approximately 13,899 annotated human genes. Pairwise analysis of tissues for differential expression at the gene level showed that the smallest differences were between tissues originating from the porcine brain. Interestingly, the relative level of differential expression at the isoform level did generally not vary between tissue contrasts. Furthermore, analysis of differential promoter usage between tissues, revealed a proportionally higher variation between cerebellum (CBE) versus frontal cortex and cerebellum versus hypothalamus (HYP) than in the remaining comparisons. In addition, the comparison of differential transcription start sites showed that the number of these sites is generally increased in comparisons including hypothalamus in contrast to other pairwise assessments. A comprehensive analysis of one of the tissue contrasts, i.e. cerebellum versus heart for differential variation at the gene, isoform, and transcription start site (TSS), and promoter level showed that several of the genes differed at all four levels. Interestingly, these genes were mainly annotated to the “electron transport chain” and neuronal differentiation, emphasizing that “tissue important” genes are regulated at several levels. Furthermore, our analysis shows that the “across tissue approach” has a promising potential when screening for possible explanations for variations, such as those observed at the gene expression levels.

Farajzadeh, Leila; Hornshøj, Henrik; Momeni, Jamal; Thomsen, Bo; Larsen, Knud; Hedegaard, Jakob; Bendixen, Christian; Madsen, Lone Bruhn, E-mail: LoneB.Madsen@agrsci.dk

2013-08-23

377

Global Mercury Pathways in the Arctic Ecosystem  

NASA Astrophysics Data System (ADS)

The sudden depletions of atmospheric mercury which occur during the Arctic spring are believed to involve oxidation of gaseous elemental mercury, Hg(0), rendering it less volatile and more soluble. The Hg(II) oxidation product(s) are more susceptible to deposition, consistent with the observation of dramatic increases in snow mercury levels during depletion events. Temporal correlations with ozone depletion events and the proliferation of BrO radicals support the hypothesis that oxidation of Hg(0) occurs in the gas phase and results in its conversion to RGM (Reactive Gaseous Mercury). The mechanisms of Hg(0) oxidation and particularly Hg(II) reduction are as yet unproven. In order to evaluate the feasibility of proposed chemical processes involving mercury in the Arctic atmosphere and its pathway after deposition on the snow from the air, we investigated mercury speciation in air and snow pack at Resolute, Nunavut, Canada (latitude 75° N) prior to and during snow melt during spring 2003. Quantitative, real-time information on emission, air transport and deposition were combined with experimental studies of the distribution and concentrations of different mercury species, methyl mercury, anions, total organic carbon and total inorganic carbon in snow samples. The effect of solar radiation and photoreductants on mercury in snow samples was also investigated. In this work, we quantify mercury removed from the air, and deposited on the snow and the transformation to inorganic and methyl mercury.

Lahoutifard, N.; Lean, D.

2003-12-01

378

Levels of heavy metals in tissues of shingi fish (Heteropneustes fossilis) from Buriganga River, Bangladesh.  

PubMed

Heavy metal pollution was reported in commercially valuable freshwater edible fish in the Buriganga River, Bangladesh. The concentrations of As, Pb, Cd, Cr, Zn, and Cu were investigated in the muscle, gill, stomach, intestine, and liver of Heteropneustes fossilis caught at three stations to assess the degree of fish pollution by heavy metals. Significant differences in concentrations of analyzed elements were observed among different tissues, but not among the stations. The ranges of the measured concentrations (?g/g dry weight) in the tissues of H. fossilis were as follows: arsenic concentration was (0.2-0.4), (0.82-0.90), (3.29-3.99), (2.20-2.80), and (2.41-2.90), that of lead was (1.79-2.20), (4.95-6.55), (10.36-13.38), (5.74-9.70), and (18.20-18.79), that of cadmium was (0.3-0.4), (2.87-4.27), (1.03-1.63), (1.55-4.59), and (2.25-5.50), that of chromium was (1.40-1.70), (3.52-3.72), (2.28-5.29), (2.77-3.79), and (4.25-8.65), that of zinc was (24.47-28.82), (16.82-18.80), (20.22-22.20), (22.86-26.68), and (60.82-67.80), and that of copper was (7.80-8.50), (6.22-6.81), (38.21-44.25), (17.07-21.03), and (43.24-47.30) in the muscle, gill, stomach, intestine, and liver, respectively. This research showed that the liver appeared to be the main heavy metal storage tissue, while the muscle had the lowest levels of analyzed metals. The concentrations of metal in the muscles not exceeded the acceptable levels for a food source for human consumption. PMID:23132754

Begum, Aleya; Mustafa, Ahmed Ismail; Amin, Md Nurul; Chowdhury, Tasrina Rabia; Quraishi, Shamshad Begum; Banu, Nasrin

2013-07-01

379

River transport of mercury from artisanal and small-scale gold mining and risks for dietary mercury exposure in Madre de Dios, Peru.  

PubMed

Artisanal and small-scale gold mining (ASGM) is a major contributor to deforestation and the largest anthropogenic source of atmospheric mercury worldwide. Despite significant information on the direct health impacts of mercury to ASGM miners, the impact of mercury contamination on downstream communities has not been well characterized, particularly in Peru's Madre de Dios region. In this area, ASGM has increased significantly since 2000 and has led to substantial political and social controversy. This research examined the spatial distribution and transport of mercury through the Madre de Dios River with distance from ASGM activity. This study also characterized risks for dietary mercury exposure to local residents who depend on fish from the river. River sediment, suspended solids from the water column, and fish samples were collected in 2013 at 62 sites near 17 communities over a 560 km stretch of the Madre de Dios River and its major tributaries. In areas downstream of known ASGM activity, mercury concentrations in sediment, suspended solids, and fish within the Madre de Dios River were elevated relative to locations upstream of mining. Fish tissue mercury concentrations were observed at levels representing a public health threat, with greater than one-third of carnivorous fish exceeding the international health standard of 0.5 mg kg(-1). This study demonstrates that communities located hundreds of kilometers downstream of ASGM activity, including children and indigenous populations who may not be involved in mining, are at risk of dietary mercury exposure that exceed acceptable body burdens. This report represents the first systematic study of the region to aid policy decision-making related to ASGM activities in Peru. PMID:25573610

Diringer, Sarah E; Feingold, Beth J; Ortiz, Ernesto J; Gallis, John A; Araújo-Flores, Julio M; Berky, Axel; Pan, William K Y; Hsu-Kim, Heileen

2015-02-11

380

Insulin action in aging man: evidence for tissue-specific differences at low physiologic insulin levels.  

PubMed

This study examined the effect of age on insulin action in several tissues. Euglycemic insulin clamp studies were performed on healthy young (n = 7, 20 to 35 years, 10 and 20 mU/m2 X min insulin infusions) and old (n = 7, 66 to 80 years, 8 and 16 mU/m2 X min insulin infusions) adults. Insulin values were similar during both the lower (young, 24 +/- 1.6, old, 24 +/- 2.1 microU/ml) and higher (young, 40 +/- 3.3; old, 39 +/- 3.8 microU/ml) insulin infusion rates. Although suppression of hepatic glucose output (HGO) was more rapid (p less than .05) in the elderly group at each dose, HGO was eventually suppressed to similar levels in both age groups (low dose: young, 34.4 +/- 10.8, old, 25.3 +/- 1.8 mg/m2 X min; higher dose: young, 22.8 +/- 10.2, old, 6.2 +/- 2.1 mg/m2 X min). Glucose disposal was less (p less than .01) in the aged group at both insulin infusion rates. Suppression of C-peptide was slower in the elderly participants (p less than .05) in the low dose study. Suppression of free fatty acid and glucagon levels was the same in each age group. We concluded that the insulin resistance of aging is not generalized to all tissues. PMID:3546473

Meneilly, G S; Minaker, K L; Elahi, D; Rowe, J W

1987-03-01

381

Semiquantitative probe for radiation-induced normal tissue damage at the molecular level  

SciTech Connect

Sheep antibodies to bovine type I collagen were employed in the immunohistochemical detection of type I collagen in lung tissue sections of irradiated LAF1 mice. A video image digitizing system was developed to estimate collagen levels, by assigning a numerical value (0-63) to each of approximately 53,800 picture elements (pixels) in the microscope field, according to the collagen-dependent fluorescence intensity at each locus. For lungs harvested 52 weeks subsequent to graded doses of 60Co gamma radiation between 0 and 10 Gy, a dose-dependent increase in type I collagen was observed in the alveolar walls. A reproducible increase was evident for doses as low as 5 Gy: doses of 7 to 10 Gy elicited type I collagen levels significantly elevated with respect to those of age-matched controls. These results are consistent with a role for type I collagen in the development of radiation-induced pulmonary fibrosis. The assay system developed here will be used to explore the role of connective tissue macromolecules in the development of radiation pneumonitis and fibrosis.

Miller, G.; Siemann, D.; Scott, P.; Dawson, D.; Muldrew, K.; Trepanier, P.; McGann, L.

1986-01-01

382

Snapping turtles (Chelydra serpentina) as monitors for mercury contamination of aquatic environments.  

PubMed

We assessed the distribution of mercury in snapping turtles (Chelydra serpentina) by analyzing front shoulder muscle, back leg muscle, tail muscle, blood, liver, and marginal carapacial scute (shell) of 26 adult turtles from five small lakes. Total mercury concentration in muscle ra