Determination Of Mercury Levels Research Articles

Evaluation of mercury levels in Pangasius and Cod fillets traded in Sicily (Italy)

Predator fishes at the top of the aquatic food chain can accumulate large concentrations of metals and their consumption, consequently, makes a significant contribution, in particular, to mercury intake. The aim of this study was to determine mercury levels in fillets of two predatory species: pangasius (Pangasius hypophthalmus) from the Vietnam region of Megong and Chao Pharayai and cod (Gadus morhua) from the Baltic and North Sea, both being commercially important in the Italian market. A comparative analysis of these two imported fish species was carried out as a risk assessment for consumer safety. The results showed the presence of higher mercury levels in pangasius (0.41 ± 0.08 mg kg−1) than in cod (0.11 ± 0.004 mg kg−1) fillets. These data underline the importance of monitoring on imported fish before marketing, to evaluate better the risk of mercury exposure through fish and seafood consumption, and of selecting safer fishes for consumption by those groups more sensitive to the toxic effects of this metal.

Mercury in Environmental and Biological Samples Using Online Combustion with Sequential Atomic Absorption and Fluorescence Measurements: A Direct Comparison of Two Fundamental Techniques in Spectrometry

In this laboratory experiment, students quantitatively determine the concentration of an element (mercury) in an environmental or biological sample while comparing and contrasting the fundamental techniques of atomic absorption spectrometry (AAS) and atomic fluorescence spectrometry (AFS). A mercury analyzer based on sample combustion, concentration of mercury by gold amalgamation, and AAS is coupled to a mercury-specific AFS system, allowing for the same sample to be carried through the two systems. This provides a direct and accurate comparison between the methods that is readily understandable by students. By calculating figures of merit for each technique, including the method detection limit, sensitivity, dynamic range, precision, and accuracy, students gain a better understanding of each quantity, and how they can be used to compare instruments and select the most suitable method under particular circumstances. Following an inquiry-based pedagogy, students determine mercury levels in solid samples (e.g., soil, leaves, fish, hair, tobacco, etc.) that they choose, collect, and analyze directly, without time-consuming and potentially hazardous hot-acid digestions. Overall, the lab promotes critical thinking about performance characteristics of different instruments and environmental analyses and is suitable for an instrumental analysis or environmental chemistry course.

Scalp hair and saliva as biomarkers in determination of mercury levels in Iranian women: Amalgam as a determinant of exposure

The aim of this study was to determine the relationship between mercury concentrations in saliva and hair in women with amalgam fillings and its relation with age and number of amalgam fillings. Eighty-two hair and saliva samples were collected randomly from Iranian women who have the same fish consumption pattern and free from occupational exposures. The mean ± SD age of these women was 29.37 ± 8.12 (ranged from 20 to 56). The determination of Hg level in hair samples was carried out by the LECO, AMA 254, Advanced Mercury Analyzer according to ASTM, standard No. D-6722. Mercury concentration in saliva samples was analyzed by PERKIN-ELMER 3030 Cold Vapor Atomic Absorption Spectrophotometer. The mean ± SD mercury level in the women was 1.28 ± 1.38 μg/g in hair and 4.14 ± 4.08 μg/l in saliva; and there were positive correlation among them. A significant correlation was also observed between Hg level of saliva (Spearman's ρ = 0.93, P < 0.001) and hair (Spearman's ρ = 0.92, P < 0.001) with number of amalgam fillings. According to the results, we can conclude that amalgam fillings may be an effective source for high Hg concentration in hair and releasing the mercury to the saliva samples.

Mercury(II) and methyl mercury speciation on Streptococcus pyogenes loaded Dowex Optipore SD-2

A solid phase extraction procedure based on speciation of mercury(II) and methyl mercury on Streptococcus pyogenes immobilized on Dowex Optipore SD-2 has been established. Selective and sequential elution with 0.1 mol L −1 HCl for methyl mercury and 2 mol L −1 HCl for mercury(II) were performed at pH 8. The determination of mercury levels was performed by cold vapour atomic absorption spectrometry (CVAAS). Optimal analytical conditions including pH, amounts of biosorbent, sample volumes, etc., were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries were also investigated. The capacity of biosorbent for mercury(II) and methyl mercury was 4.8 and 3.4 mg g −1. The detection limit (3 sigma) of the reagent blank for mercury(II) and methyl mercury was 2.1 and 1.5 ng L −1. Preconcentration factor was calculated as 25. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure is performed by the analysis of standard reference material (NRCC-DORM 2 Dogfish Muscle). The procedure was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and environmental samples.

Body burdens of mercury in lower Hudson River area anglers

The Hudson River has been a federally designated Superfund site for over 20 years. Discharges of industrial waste and of treated and untreated sewage and atmospheric deposition have introduced mercury and other persistent pollutants to the Hudson River ecosystem. Despite New York and New Jersey health advisories, many local anglers and their family members continue to consume fish caught from the river. To evaluate associations between body burden of mercury and local fish consumption, we conducted a cross-sectional study of 191 anglers recruited from piers and fishing clubs. Participants were administered a questionnaire to obtain information on local fish consumption, and 65% (124 individuals) provided a blood sample used to determine mercury levels. Mercury levels ranged from below the limit of detection (0.75 ng/mL) to 24.0 ng/mL. Participants who reported eating locally caught fish had significantly higher levels of mercury (mean ( M)=2.4 ng/mL, standard error (SE)=1.2) than anglers who never ate locally caught fish ( M = 1.3 ng / mL , SE=1.1). A positive dose–response pattern was also observed, where participants who reported eating locally caught fish more than once a week had higher mercury levels ( M = 2.6 ng / mL , SE=1.1) than anglers eating fish less frequently ( M = 2.0 ng / mL , SE=1.2) or never at all ( M = 1.3 ng / mL , SE=1.1). These findings indicate that consumption of fish caught from the lower Hudson River area is a route of human exposure to mercury for the angling community.

Effect of iodine on mercury concentrations in dental-unit wastewater

This study was undertaken to determine whether iodine used to control bacteria in dental unit waterlines could increase mercury concentrations in dental wastewater. The study was conducted in four parts. Part 1. Solutions containing iodine in concentrations ranging from zero (control) to 20 mg/L were mixed with ground and sieved dental amalgam and then allowed to equilibrate by settling. Cold vapor atomic absorption spectrometry was used to determine mercury levels in the settled supernatants at 24 h and at 7 days. Part 2. Deionized water was pumped through an iodine-releasing water-treatment cartridge, collected, and mixed with ground and sieved dental amalgam. Mercury levels in settled supernatants were measured at 24 h and at 7 days. Part 3. Iodine in water from two commercial iodine-releasing cartridges was measured using Inductively Couple Plasma Mass Spectrometry. Part 4. Baseline mercury levels in settled supernatants from wastewater collected from two dental chairs were compared to samples taken from chairs equipped with iodine-releasing cartridges. Part 1. A linear correlation between iodine and mercury concentration (r2=0.9167 and 0.9459, respectively, both P<0.001) was seen at both 24 h and 7 days. Part 2. Mean mercury levels in 24h samples were 3.0 times higher than the controls (0.2864 mg/L compared with 0.0939mg/L for the 24 h controls). Mean mercury levels in the 7-day samples were 5.9 times higher than the 7-day controls (0.2048 mg/L compared with 0.0348 mg/L for the 7-day controls). Part 3. The effluent from two iodine-releasing cartridges showed iodine concentrations averaging 3.2 mg/L (n=10, SD=0.8, range=2.5-4.6). Part 4. Data from the clinical study showed a statistically significant 2.5-fold increase in mercury levels with iodine-containing samples compared to baseline (0.0853 mg/L, n=18, SD=0.0441 and 0.0345 mg/L, n=18, SD=0.0145, respectively; P<0.001). Data suggest that iodine can increase concentrations of dissolved mercury in dental unit wastewater.

Exposição humana ao mercúrio na Amazônia brasileira: uma perspectiva histórica

The objective of the present article was to present the most important data generated by a multicentric study carried out by Brazilian researchers who, with the support of national and international institutions, worked during the 1990s to describe human exposure to mercury in gold mining areas in the Brazilian Amazon. Three sets of procedures were followed with residents of the Tocantins and Xingu river basins: (1) clinical examination, based on a standardized protocol and performed by a single researcher, in order to identify five basic levels of contamination; (2) determination of mercury levels in blood, hair, and urine, using atomic absorption spectrophotometry (Xingu Project); and (3) investigation of genotoxicity by using four cytogenetic indicators. During the first stage, 41 individuals were studied. Mercury was found in miners and their family members. Contamination was significantly associated with occupation and showed a differential correlation with genotoxicity indicators. After that, the Xingu project, which encompassed 625 individuals, focused on 417 Kayapó natives from the Gorotire and Djudjetiktire villages; 142 miners; and 66 riverine individuals (ribeirinhos). The highest levels of methylmercury in hair and total mercury in blood and urine were found among the Indian population. Contamination with inorganic forms of mercury was also observed in the blood, hair, and urine of Indians. Following a specific recommendation from the World Health Organization, special attention was given to pregnant Gorotire and Djudjetiktire women, who, although not directly exposed to mercury vapors, showed considerable levels of mercury intoxication. Despite this worrisome scenario, a number of social achievements in the 1990s point to new standards of dignity in health care and of social ethics in Brazil that could benefit everyone, including the victims of environmental injury.

Determination of mercury levels in human urine and blood by ultraviolet-visible spectrophotometry.

A method for the determination of mercury levels in biological samples, i.e., human urine and blood, has been developed using an incomplete cubane-type sulfur-bridged molybdenum aqua complex, Mo3S4(4+)(aq), with analysis by spectrophotometry. The primary advantage of the method is that when the 'complex' is dissolved in sulfuric acid it reacts directly with mercury, produced by the addition of a reducing agent to samples containing mercury(II), giving an intense coloration. Levels of mercury in the biological samples can be determined using the 'complex' dissolved in sulfuric acid. The detection limit for mercury(II) in urine and blood was 0.05 ppm at the wavelength of maximum absorption (lambda max = 556 nm).

Genotoxicity and bioaccumulation of methyl mercury and mercuric chloride in vivo in the newt Pleurodeles waltl.

Larvae and embryos of the urodele amphibian Pleurodeles waltl were raised for several days in water containing low concentrations of methyl mercuric chloride (CH3HgCl) or mercuric chloride (HgCl2). Examination of squash preparations from treated embryos showed that both compounds induced chromosome breaks and c-mitosis. Examination of blood smears from the larvae demonstrated a higher level of micronucleated erythrocytes in the animals raised in the mercury-containing water than in controls raised in uncontaminated water. The bioaccumulation of both compounds was evaluated by determination of mercury levels in the larvae. After 12 days of treatment, concentration factors (concentration in the organism/concentration in the water) of approximately 1200 and approximately 600 were found for methyl mercury and mercuric chloride, respectively.

Mercury content in sharks.

Prior to the occurrence of the Minamata disaster in Japan in which 46 people were killed and nearly I00 seriously injured by eating fish and shellfish contaminated by an alkylmercury compound (KURLAND et al. 1960) there had been few attempts to determine mercury levels in fish. However, RAFDER & SNEKVIK in 1941 reported levels in freshwater and marine fish from contaminated areas markedly higher than those found in uncontaminated waters. Prom 1964 to 1967, studies were conducted on fish in Sweden, and mercury concentrations of several ppm were reported, as was the observation that fish were found to contain mercury higher than that noted in waters from which they had been caught (VOSTEL 1972). Also, positive correlation between mercury concentrations in muscle tissue to total weiqht and age was confirmed (BACHE et al. 1971). This paper reports the analytical results relating

Determination of mercury levels in the brain by neutron activation analysis: In memory of Dr S. Alhshimi, ex-head of the health physics department, nuclear research center

Brain concentration of mercury as low as 100 ppm were determined by detecting the 368 keV prompt γ-radiation emitted during the 199Hg( n,γ) 200Hg reaction at doses of 102 mrem. Phantom studies demonstrated that the assay was accurate to within ±3,2%. A 60 cm 3 Ge(Li) detector of 2.14 keV resolution at the 60Co line was used to view the parietal region of the skull. Spatial consideration is given to the dose measurements. An approach to achieve minimum shielding weight and greatest reduction in background is described. A metallic artificial mole is used to control variation in head position.

Magnitude of Mercury Levels in Fish Muscle Tissue from South Carolina Waters

Abstract Many of the world’s great gastronomic materpieces are based on fish from both freshwater and saltwater. The danger for human health, due to fish consumption, has been very well recognized. A survey of mercury residues in freshwater fish was undertaken to see if the problem of the magnitude of mercury contamination was evident in the South Carolina Fishery. These investigations were initiated to determine mercury levels in fish from a variety of South Carolina Waters. Samples of fish from freshwater sources all over the state of South Carolina were collected during 1974 and 1975. The species composition of the collections generally reflects the fish populations of the water sampled. Mercury determinations were made on 100 samples of fish taken from 22 locations covering 46 South Carolina counties. Triplicate samples of fish tissues were analyzed using flameless atomic absorption procedures. Findings of this report are that magnitude of mercury levels of fish from Lake Jocassee and Edisto River have been found to be higher than other waterways surveyed. Mercury levels exceeding the U. S. Food and Drug Administration guideline of 0.5 ppm have been found in Brown Trout, Pike and Mudfish. Different patterns of mercury concentration occurred between different tissues. Larger fish contain higher concentration of mercury than do smaller fish of the same species.