Mercury Content In Tissues Research Articles

Аккумуляция ртути в двустворчатых моллюсках в гидроэкосистеме устьевой области реки Красная (Вьетнам)

The article presents analysis of mercury content in different tissues such as gills, mantle, hepatopancreas and body (leg) in 4 species of bivalve molluscs in the estuary of the Red River in Vietnam. The studies were carried out in 2016–2021 during the main hydrological seasons (during the summer flood and winter low water) at 37 stations in the delta and estuarine coast of the Red River. There are shown the dependences of mercury content in mollusc tissues on the age parameters (length and mass of tissues) and on the content of pollutant in dissolved, suspended forms of near-bottom water layers and in bottom sediments. The mercury content in the tissues of molluscs varies whithin 0,023 ± 0,001 to 0,459 ± 0,007 mg/kg wet weight. The highest content of mercury was found in the hepatopancreas 
 of Austriella corrugata, and the lowest - in the leg of Lutraria rhynchaena. Significant close positive correlations were registered between the mercury concentrations in the mollusc tissues and the mercury content in the near-bottom water layer and in bottom sediments (r from 0.68 to 0.92, p < 0.05). All studied species of molluscs are classified as macroconcentrators of mercury in water; Austriella corrugata can actively accumulate mercury not only from the water, but also from the bottom sediments. Bivalve molluscs can be used as an object of biomonitoring when studying the distribution of mercury in the estuary of the Red River.

Do the total mercury concentrations detected in fish from Czech ponds represent a risk for consumers?

Mercury is one of the important pollutants of the environment. Therefore, it’s necessary to monitor quantity of mercury especially in aquatic ecosystems. The main goal of the presented study was to compare the content of total mercury in tissues of fish coming from the Czech Republic, an important carp exporter, with focus on comparison of mercury content between 3 different ponds, its comparison between different fish species and between different tissues of the same species, and estimation whether the mercury content in tissues meets the limit given in the Commission Regulation (EC) No. 1881/2006 or not. Total mercury concentration was measured in 90 fish specimen sampled from three ponds (Velky Kocelovicky, Mysliv and Zehunsky) in autumn 2018. The values of total mercury in fish tissues was measured by atomic absorption spectrometry. The content of total mercury in the tissues decreased as follows: muscle > liver > gonads > scales. The highest average content of total mercury in muscle was 0.1517 ± 0.0176 mg/kg coming from pike caught in Velky Kocelovicky pond. In contrast, the lowest average content of total mercury in muscle 0.0036 ± 0.0003 mg/kg was found in carp tissue coming from the locality of Zehunsky pond. We confirmed that the predatory fish are more exposed to mercury than non-predatory fish. None of the monitored localities exceeded the set regulatory limit. Thus, our study shows that fish coming from these ponds are safe in terms of total mercury content.

Assessment of total mercury content in tissues of Mullus argentinae in Rio de Janeiro, Brazil

Assessment of total mercury content in tissues of Mullus argentinae in Rio de Janeiro, Brazil

Mechanism of renal injury and apoptosis in rats with nephrotic syndrome induced by mercury

Objective: To investigate the relationship between renal injury and apoptosis in rats with nephrotic syndrome induced by mercury, in order to find out the pathogenesis. Methods: Forty-eight healthy male SPF-grade BN (Brown-Norway) rats were divided into the control group and the exposure group by random number table. The nephrotic syndrome was caused by subcutaneous injection of HgCl(2) (1 mg/ml) in the abdominal weight per kg of body weight. The control group was injected with the same volume of NaCl as the exposure group. Some rats were sacrificed on the 14th, 21st, 28th, and 35th days, and the serum kidney injury indicators creatinine (CRE) and urea nitrogen (BUN) were detected, and the renal tissue mercury content was detected; the in situ terminal transferase labeling technology (TUNEL) was detected Apoptosis, immunofluorescence detection of Cyt C content, Western blot detection of mitochondrial pathway apoptosis-related proteins [B-cell lymphoma 2 (Bcl-2) , Bcl-2 related X protein (BAX) , cysteine proteinase 3 (Caspase 3) ], mitogen-activated protein kinase (MAPK) signaling pathway-related proteins[p38 mitogen-activated protein kinase (P38MAPK) , extracellular regulatory protein kinase (ERK) ] expression. Results: Compared with the control group, the BUN content in the serum of rats in the exposure group was significantly increased on days 7, 21, and 28, the CRE content was significantly increased on 21 days, the CRE content was significantly decreased on 28 and 35 days, and the organ coefficient and renal mercury content were 14 to 35 days. Significantly increased, and the differences were statistically significant (P<0.05) . Compared with the control group, rats in the exposed group showed increased glomerular stroma, tubule dilatation and other renal cell apoptosis at 14 to 35 days, and Cyt C expression was obvious in the exposed groups at 14, 21 days. Compared with the control group, the BAX content of the rats in the exposed group was significantly increased on the 21st day, the content of Caspase 3 in the rats on the 14th and 21st days was significantly increased, and the content of the P38MAPK in the 35th day was significantly increased (P<0.05) . Conclusion: HgCl(2) may cause renal cell damage through the mitochondrial pathway of apoptosis and cause nephrotic syndrome, and the MAPK signaling pathway may regulate this process and exert an inhibitory effect on apoptosis.

Variations in Tissue Mercury Contents in Three Species of Adult Salamanders in Streams in Western Maryland.

The purpose of this study was to improve our understanding of the relationship between mercury in three species of adult salamanders and relatively pristine first-order streams in western Maryland. We measured the tissue mercury content of 106 northern two-lined salamanders (Eurycea bislineata bislineata), 111 northern dusky (Desmognathus fuscus), and 107 Allegheny mountain dusky (Desmognathus ocrophaeus) salamanders collected during three sampling periods. Averaged over our entire data set, northern two-lined salamanders had significantly greater tissue mercury contents (29.57 ± 1.32ngg-1) than northern dusky (20.95 ± 0.78ngg-1) and Allegheny mountain dusky salamanders (22.84 ± 1.23ngg-1). This may be due in part to the longer larval period of the northern two-lined salamanders (24-36 vs. 0-10months). A longer larval period suggests that the northern two-lined larvae were consuming a fully aquatic diet for a longer time period, which is likely to be higher in mercury compared with a more terrestrial diet. The tissue mercury content in northern two-lined and northern dusky salamanders were strongly correlated with the average total mercury, methyl mercury, and dissolved organic carbon concentrations in stream water. In contrast, the tissue mercury content of the more terrestrial salamander, the Allegheny mountain dusky, was not correlated with stream water chemistry. This suggest that the mercury in the terrestrial prey consumed by the Allegheny mountain dusky salamanders is not directly linked to the mercury in stream water. Our results also suggest that the aquatic salamanders could be important bioindicators of mercury contamination of small streams.

Mercury Concentrations in Northern Two-Lined Salamanders from Stream Ecosystems in Garrett County, Maryland.

The purpose of this study was to increase our understanding of the bioaccumulation of mercury in northern two-lined salamanders (Eurycea bislineata bislineata) in freshwater stream ecosystems. We collected 111 adults and 131 larval northern two-lined salamanders from six streams in Garrett County, Maryland. These salamanders were collected in April, July, and September 2010. We measured the size and tissue mercury content in all of these salamanders. We also measured the total and methyl mercury concentrations in stream water on monthly basis from April through December 2010. Averaged over all stream ecosystems, adult northern two-lined salamanders had significantly greater total mercury concentrations than larval salamanders (29.6 vs. 23.8ngg-1). For individual stream ecosystems, the mean tissue mercury contents in adult northern two-lined salamanders were significantly greater than the mean tissue mercury contents in larval northern two-lined salamanders for Bear Pen and Mill Run. Adult and larval salamanders from the Little Savage River and Mud Lick had 1.5-2 times greater mean tissue mercury contents than salamanders in all other streams. These two streams also had significantly greater total and methyl mercury concentrations. Despite their different life-stage feeding behaviors (terrestrial vs. aquatic), the tissue mercury contents of adult (r=0.76) and larval (r=0.79) northern two-lined salamanders were strongly linked to the methyl mercury concentrations in stream water. This implies that northern two-lined salamanders may be a useful bioindicator of mercury pollution in relatively pristine stream ecosystems.

Changes in mercury concentration in muscles, ovaries and eggs of European eel during maturation under controlled conditions

The degradation of the environment, namely due to pollution causes increasing impact on the organisms living on it, especially those at the top of the trophic chain. The accumulation of heavy metals such as mercury in live organisms may have a negative effect on the efficiency of reproduction. The aim of this study was to determine the mercury (Hg) content in muscles, ovaries and eggs during final maturation of gametes and after ovulation of European eel females. To this end, 65 (53 as treated and 12 as control) female European eels collected in Poland were analysed for mercury content. Eels were caught during commercial fishing activities in fresh water in the Warmia and Mazury region. Females were stimulated with carp pituitary homogenate (CPH) at 18mgkg−1, at 5-day intervals, for 20 weeks. The hormones were not given to the fish in the control group. The mercury content in tissues was determined by atomic absorption using a Milestone DMA-80 and analysis showed statistically significant differences (P < 0.05) between the content of mercury in muscle, ovary and eggs. The total mercury concentration in females following spawning increased in muscles and ovaries. Female eel eggs (0.0031 ± 0.0003mgkg−1 w/w) were found to contain eight times less mercury than their ovaries (0.026 ± 0.002mgkg−1 w/w) and 78 times less than their muscles (0.24 ± 0.03mgkg−1 w/w). The concentration of mercury in both muscles and ovaries in fish increases after spawning, which can additionally confirm that mercury is transmitted in small amounts from the mother's body to eggs.

Synergistic Effects of Dietary Vitamin C, E and Selenomethionine on Growth Performance, Tissue Mercury Content and Oxidative Biomarkers of Juvenile Olive Flounder,Paralichthys olivaceus(Temminck &amp; Schlegel) Toxified with the High Dietary Methylmercury

A 10-week feeding trial was conducted to evaluate the tissue level synergistic effects of dietary vitamin C, E and selenomethionine (SeMet) on dietary methylmercury (MeHg) toxicity in juvenile olive flounder, Paralichthys olivaceus. Eight semi-purified diets were formulated to contain two different vitamin C levels as L-ascorbyl-2-monophosphate (400 and 800 mg AMP/kg diet), two vitamin E levels as DL-α-tocopheryl acetate (100 and 200 mg TA/kg diet) and two selenium (Se) levels as selenomethionine (2 and 4 mg SeMet/kgdiet) on the constant mercury (Hg) level (20 mg MeHg/kgdiet). Eight experimental diets, in a 2×2×2 factorial design (C400E100Se2, C400E100Se4, C400E200Se2, C400E200Se4, C800E100Se2, C800E100Se4, C800E200Se2 and C800E200Se4) were fed to triplicate group of fishes averaging 3.12±0.04g (mean±SD) in the semi-recirculation system. After 10 weeks of feeding trial, weight gain (WG) offish fed diets containing C400E200Se4, C800E100Se2 and C800E200Se2 were significantly higher than those of fish fed diets containing C400E100Se2 and C400E100Se4 (P<0.05). Feed efficiency (FE), specific growth rate (SGR), protein efficiency ratio (PER) showed a similar trend as WG. The most significant depleting trend of mercury accumulation was found in kidney tissue. Tissue oxidative biomarkers like superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS) in liver and kidney tissues improved up to higher levels of vitamin C, E and Se. Therefore, these findings indicated that the best combinations of dietary antioxidant levels could be C400E200Se4 or C800E200Se2 diet based on WG by analysis of variance (ANOVA) test in terms of reducing tissue MeHg content in juvenile olive flounder.

Protective role of melatonin in myocardial oxidative damage induced by mercury in murine model

This study was designed to investigate the electrophysiological, hemodynamic and biochemical parameters of mercuric chloride and methylmercury exposure on cardiovascular functions and its modulation by melatonin in vivo. Wistar albino rats were divided into six group containing 10 animals each. Mercuric chloride (3.75 µM/L) in drinking water and methylmercury (0.5 mg/kg/day) through gavage, given for 1 month, induced a statistically significant increase (p < 0.001) in left ventricular end diastolic pressure, blood and cardiac tissue mercury content and myocardial lipid peroxides compared to control. Significant attenuation (p < 0.05) of baroreflex sensitivity and depletion of myocardial endogenous antioxidants (p < 0.001) viz. Reduced glutathione (GSH) and superoxide dismutase (SOD) were also found in the mercury-exposed groups as compared to control group. Mercury exposure followed by subacute treatment with melatonin (4 µg/mL/day) in drinking water for 1 month significantly lowered (p < 0.01) left ventricular end diastolic pressure and lipid peroxide levels and increased baroreceptor sensitivity (p < 0.001) and also levels of GSH and SOD (p < 0.001) as compared to mercury-exposed rats. The results of our study provide clear evidence that elevated oxidative stress and altered baroreflex mechanisms caused by mercury intoxication may be the contributing factors responsible for impairment of cardiovascular functions and melatonin may exhibit cardioprotective property against subacute heavy metal intoxication and enhance the antioxidant defense against mercury-induced oxidative myocardial injury in rats.

Mercury content in tissues of rats given diet containing dental amalgam powder.

Mercury content in tissues of rats given diet containing dental amalgam powder.

Differential elimination of mercury during maturation of leguminous seeds

The pods of Acacia koa, Canavalia cathartica, Leucaena leucocephala, Samanea saman and six other leguminous species lose as much as 75–85 % of their tissue water during maturation, but show no loss in tissue mercury content. Unlike fruit, seeds not only lose most of their water content, but also at least 75 % of their mercury during the maturation process. It is suggested that selective elimination is more likely to take place by bio-volatilization rather than by translocation, and that the phenomenon allows for detoxification of a cytogenetically hazardous chemical substance.

Effect of dental amalgam restorations on the mercury content of nerve tissues.

In an autopsy study in two men and an experimental study performed on three female beagles the mercury burden of nerve tissues was determined. Nerve tissues from the head and face region and from three peripheral nerves were analyzed for mercury content with the aid of atomic absorption spectroscopy. In the dogs dental amalgam restorations were placed so as to investigate the possible influence from the amalgam on the mercury content of the tissues under study. The mercury content in man and dogs differed widely from one nerve to another, with no apparent relation to the number, type, or location of tooth restorations.

Mercury and selenium content and chemical form in vegetable crops grown on sludge-amended soil.

The content and chemical form of mercury and selenium were assessed for several vegetable crops grown on sludge-amended and untreated soil. Total edible tissue mercury and selenium content of sludge-grown crops averaged four and two times higher, respectively, than that of crops grown on untreated soil. In terms of plant/soil concentration factors, selenium was more readily assimilated by crops than mercury. Crops from sludged and untreated soil had methylmercury levels averaging 14.0 and 4.4%, respectively, of the total tissue mercury content. An average of 24% of the total tissue selenium content was present as hexavalent selenium.

Subacute toxicity of methylmercury in the adult cat

A dose of 0.25 mg Hg/kg/day was administered po to 2 groups of cats for 12–14 weeks, either as pure methylmercuric chloride or as methylmercury-contaminated fish. A control group received a diet containing uncontaminated fish. Clinical signs of methylmercury intoxication consisting of ataxia, intention tremor and impaired righting reflex and convulsions developed between 55 and 96 days in both treated groups, at which time the total dose received was between 14 and 24 mg Hg/kg. Tissue mercury content was similar in both groups of treated animals, as were the pathologic changes. Lesions were found in the cerebellar vermis and the cerebral cortex. The changes consisted of loss of nerve cells with replacement by reactive and fibrillary gliosis. Chromosome studies of terminal bone marrow samples showed no abnormalities. A separate group of 8 cats received a single oral dose of 203H-labelled methylmercuric chloride, and the blood mercury concentration was measured weekly. The t 1 2 for the elimination of mercury from blood was found to be 39 ± 4 days (mean ± SE).

Exposure mode to mercury vapor and body burden in the rat and its decreasing pattern

The author exposed rats to mercury vapor and measured mercury content in tissues. Exposure modes consisted of two groups; the HS, high concentration-short term exposure group (6.0mg/m3 in Hg concentration×1 hr. in daily duration of exposure, 3.0×1 and 1.5×1) and the LL, low concentration-long term exposure group (1.0×6, 1.0×3 and 1.0×1.5). Each exposure was continued 5 days a week for 2 or 4 consecutive weeks in an exposure chamber. Quantitative mercury determination was performed by a dithizone method. Mercury concentration of the lungs of the HS group after both the 2 and 4 weeks exposure was higher than that of the lungs of the LL group. That of the other tissues of the HS group was lower than that of the LL group. Mercury content in tissues of rats treated by the exposure mode 1.0×6 was measured up to 16 weeks after the termination of mercury exposure. The mercury content decreased lineally in semilogarithmic scales. The half time of mercury content of the lungs was about 13 days, the shortest and that of the brain was about 210 days, the longest among tissues.