High Amounts Of Hg Research Articles

Toxicological risk in individuals exposed to methylmercury and total mercury through daily-consumed foodstuffs in one of the mining regions of Bajo Cauca, Antioquia, Colombia

Mercury (Hg), and its different chemical forms, such as methylmercury (MeHg), are highly toxic compounds that affect the environment as well as human and animal health. Specifically, mining practices may cause these metals to be present in water, air, soil, and food. This study examines the concentration levels of Hg and MeHg in locally-consumed foodstuffs, including fish, pork, chicken, yam, plantain, and cassava, in a specific region of Antioquia (Colombia) by assessing the toxicological risk to the population due to the exploitation of open-pit alluvial mining in the area. Among foods examined, the highest amount of Hg was found in fish > pork > chicken > cassava > plantain > yam (ranging from 207.87 to 0.23 μg/g). Conversely, MeHg was identified in cassava > fish > plantain > chicken > yam > pork in amounts ranging from 1.567 to 0.434 μg/g. The risk exposure factors of the acceptable daily intake (ADI) and the provisional tolerable weekly intake (PTWI) for Hg and MeHg exhibited a trend similar to the amount of metal in the assessed foods. This work contributed to characterizing and preventing public health problems in a mining population in the Bajo Cauca region of Antioquia, which requires special attention due to their potential exposure to Hg and MeHg through the most locally consumed foods.

Dietary Intake of Toxic Heavy Metals with Major Groups of Food Products-Results of Analytical Determinations.

Food contains a complex matrix of various substances, including essential nutrients, non-nutritive substances, and toxins, including metals. The main purpose of the study was to evaluate the contribution of major groups of food products to an overall intake of toxic heavy metals (Cd, Pb, Hg, and Ni) using a combination of the 24-dietary recall technique, the ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) method, and chemometric tools. The obtained results reveal that there is a high potential risk of developing nephrotoxicity through the dietary intake of Pb in the case of both genders. The dietary intake determined for other elements (Cd, Hg, and Ni) was far below the limits established by European Food Safety Authority (EFSA). Principal Component Analysis (PCA) supported analytical determinations and revealed that cereals and vegetables were major contributors to a total intake of Cd (39.6 and 17.4% of the total exposure, respectively), Ni (40.4 and 19.3%), and Hg (16.8 and 19.6%), while water and beverages were major dietary sources of Pb (31% of the total daily intake). In contrast, eggs, fats and oils, and milk and dairy products provided the smallest amounts of Cd, Pb, and Ni. Despite containing high amounts of Hg, considering very low consumption, fish were not found to be an important source of this element.

Risk of Mercury Ingestion from Canned Fish in Poland.

In this study, total mercury content was determined in 84 canned fish corresponding to commonly consumed brands (over 14 different producers), which were purchased from local markets in Poland in the years 2019–2020. For comparison purposes, samples of both the matrix in which the fish were kept along with the seafood samples were measured. The analyses were carried out using the cold vapor AAS technique. Statistical analyses were employed to identify significant differences in mercury content in relation to the selected criteria such as fish species, type of fish (predatory, non-predatory) and the producer brand. The obtained results were compared against domestic and international standards as well as with the literature data in order to evaluate the safety of the canned fish consumption. The study revealed that none of canned fish exceeded the acceptable levels set by the FAO/WHO. The highest amount of Hg was recorded for canned tuna (maximum 351.30 µg/kg, mean 74.38 µg/kg). Further, the estimated tolerable dose of weekly mercury intake suggests that the consumption of over 1.8 cans of fish with the highest mean mercury content should not pose a risk to consumers in Poland according to international standards. Among the ten highest mean results for mercury, five of them belonged to canned tuna (Bonito species) kept in different matrices. These consisted of seven domestic and three imported brands of fish products, which is a worrying message for a local community. Mercury content in predatory fish differed significantly from the results gathered for non-predatory fish and the total amount of mercury in studied canned fish corresponded to their status in the aquatic food chain. Moreover, significant differences were stated between various fish species and fishing areas. Fish caught in the Atlantic Ocean (cod and herring) presented higher mercury content than the ones from closed seas.

Reducing Mercury and Increasing Gold in Artisanal Gold MInes

Background: Thirty seven percent of global mercury (Hg) pollution stems from small-scale or artisanal gold mining (AGM) usually in impoverished rural communities in developing countries. Small-scale AGM is a main source of income for millions of people. Hg is used to form an amalgam with gold ore and when fired, gold metal remains. We know Hg is toxic to miners, children, waterways and wildlife. There are ways to reduce this pollutionMethods: Forty years ago a small-scale gold miner in Philippines developed a mercury-free gold extraction method, borax, which apart from being nontoxic has two important benefits: it has higher gold-recovery and miners do not need to purchase expensive and toxic Hg. Furthermore,waste tailings from AGM contain high amounts of Hg which slowly evaporates and contributes to global pollution. Appelglobal and partners have developed methods—Peter Plates-- to recover much of the Hg bound gold in the tailings. A byproduct of recovery produces greater amounts of gold – a win-win procedure.Results: The borax Hg-free gold extraction method has positive environmental and health benefits, and has also been shown to recover between 50 to74% more gold than the traditional method. Projects demonstrating Hg-free gold extraction have been carried out in Philippines, Uganda, Mozambique, Mongolia and Peru. In January 2019, a project was carried out in Uganda demonstrating that Hg-free gold extraction required 10 percent longer processing time, but recovered 40% more gold than traditional Hg methods.Conclusion: In contrast with Hg, borax gold mining methods offer clear environmental and worker benefits, and Appelglobal Hg recovery reduces water pollution and increases gold metal recovery. Adopting these methods will benefit informal gold miners and their communities.

Phytofiltration of As3+, As5+, and Hg by the aquatic macrophyte Potamogeton pusillus L, and its potential use in the treatment of wastewater

ABSTRACTThe aim of this paper was to investigate the capacity of the aquatic macrophyte Potamogeton pusillus to remove As3+, As5+, and Hg from aqueous solutions. The plants were exposed to 0 mg.L−1, 0.1 mg.L−1, 0.5 mg.L−1, 1 mg.L−1, or 2 mg.L−1 of As3+, As5+, and Hg for 20 days. The results obtained for the individual removal of As3+, As5+, and Hg from water solutions, together with their accumulation in P. pusillus, indicate that this plant can be effectively used for the removal of Hg and of moderate concentrations of As3+ or As5+ (0.1 mg.L−1) from aquatic systems. Roots and leaves accumulated the highest amount of As when the plant was exposed to As5+, but when it was exposed to As3+, the root accumulated the highest amount of As, and the leaves, the highest amount of Hg. When compared to other aquatic plants species, the results showed that P. pusillus demonstrated a higher Hg accumulation (2465 ± 293 µg.g−1) when the transfer coefficient was 40,580 ± 3762 L.kg −1, showing the great potential of this macrophyte for phytoremediation of water contaminated with Hg. To the extent of our knowledge, this is the first report on bioaccumulation of As3+, As5+, and Hg by P. pusillus.

Occurrence and speciation of arsenic and mercury in estuarine sediments affected by mining activities (Asturias, northern Spain)

Sediments contaminated by Hg and As from two historical mining areas have been deposited in the Nalón estuary (Asturias, northern Spain) since 1850. Total mercury (Hgtotal) concentrations in the sediments range from 0.20 μg g−1 to 1.33 μg g−1, most of it in the form of sulphides. Concentrations of methylmercury (303.20–865.40 pg g−1) are up to two orders of magnitude lower than the concentration of Hgtotal. Total As concentration (Astotal) is enriched compared to the background level for the area. The relative abundance of As(V) on As(III) in the sediments ranges from 97.6% to 100%, whereas inorganic Hg accounts for more than 99% of the total Hg. The occurrence of the most toxic species, inorganic As(III) and organic methylmercury, seem to be related to redox conditions together with the amounts of sulphur which act as natural barriers which inhibit the biological and chemical speciation processes. Despite the high amounts of Hg and As present in the sediments, their transference to the water column appear to be limited thus converting sediments in an effective sink of both elements. Special attention should be paid to potential variations of the environmental conditions which might increase the element mobility and exchange between sediments and the water column.

Tolerance of the forest soil microbiome to increasing mercury concentrations

Mercury (Hg) occurs naturally in soil and can reach high concentrations in the environment due to anthropogenic activities; however, little is known about its impact on the soil microbiome. Here, we tested the impact of different concentrations of Hg on soil bacterial and fungal communities by carrying out microcosm experiments with seven different forest soils. The highest concentration of Hg (32 μg Hg g−1 dry soil) caused severe diversity loss and shifts in the bacterial and fungal community structures and composition. Bioavailable Hg was reduced in soils with the highest proportion of clay, but the impact of Hg on microbial community structures was still evident in these soils. Lower concentrations of Hg (≤3.2 μg Hg g−1 dry soil) had only a limited effect on the soil microbiome. Fungal communities were generally less affected than the bacterial communities. The bacterial Hg-detoxification capacity, as assessed by mercuric reductase gene abundance, was reduced in soils with the lowest amount bioavailable Hg. We found a wide range of Hg-responsive taxa in soils spiked with high amounts of Hg, although they were generally not specific to any soil type or taxonomic group. Overall, our data show that the impacts of Hg on the soil microbiome and its detoxification responses depend on soil characteristics.

Direct online HPLC-CV-AFS method for traces of methylmercury without derivatisation: a matrix-independent method for urine, sediment and biological tissue samples.

Mercury (Hg) is a global pollutant which occurs in different species, with methylmercury (MeHg) being the critical compound due to its neurotoxicity and bioaccumulation through the food chain. Methods for trace speciation of MeHg are therefore needed for a vast range of sample matrices, such as biological tissues, fluids, soils or sediments. We have previously developed an ultra-trace speciation method for methylmercury in water, based on a preconcentration HPLC cold vapour atomic fluorescence spectrometry (HPLC-CV-AFS) method. The focus of this work is mercury speciation in a variety of sample matrices to assess the versatility of the method. Certified reference materials were used where possible, and samples were spiked where reference materials were not available, e.g. human urine. Solid samples were submitted for commonly used digestion or extraction processes to obtain a liquid sample for injection into the analytical system. For MeHg in sediment samples, an extraction procedure was adapted to accommodate MeHg separation from high amounts of Hg(2+) to avoid an overload of the column. The recovery for MeHg determination was found to be in the range of 88-104% in fish reference materials (DOLT-2, DOLT-4, DORM-3), lobster (TORT-2), seaweed (IAEA-140/TM), sediments (ERM(®)-CC580) and spiked urine and has been proven to be robust, reliable, virtually matrix-independent and relatively cost-effective. Applications in the ultra-trace concentration range are possible using the preconcentration up to 200 mL, while for higher MeHg-containing samples, lower volumes can be applied. A comparison was carried out between species-specific isotope dilution gas chromatography inductively coupled plasma mass spectrometry (SSID-GC-ICP-MS) as the gold standard and HPLC-CV-AFS for biological tissues (liver, kidney and muscle of pilot whales), showing a slope of 1.008 and R (2) = 0.97, which indicates that the HPLC-CV-AFS method achieves well-correlated results for MeHg in biological tissues.

Total Mercury in Lake Neusiedl, Austria

Between May and September 2011 a total of 361 samples from water, sediment, macrophytes and fish tissues from the shallow, slightly alkaline Lake Neusiedl were measured for their total mercury content with cold vapour atomic absorption spectroscopy (CV-AAS). Hg content of surface water was below the LOD of 0.1 μg/L and the sediments displayed contents between 0.025 and 0.113 μg/g dw, significantly correlated with the proportion of organic components (fig 1). Although these results do not point to an anthropogenic pollution of the lake, considerable amounts of mercury could be measured in fish samples and macrophytes. Both investigated submerged plant species, namely Potamogeton pectinatus and Myriophyllum spicatum show a high potential for bioaccumulation of Hg, presenting mean values of 0.245 ± 0.152 and 0.298 ± 0.115 μg/g dw respectively. Compared to freshwater fish from other unpolluted sites high amounts of Hg could be measured (fig. 2). Biomagnification and significant differences could be observed when comparing muscle samples of the planctivorous fish species rudd Scardinus erythrophthalmus (n = 10, mean = 0.084 μg/g ww) with the piscivorous perch Perca fluviatilis (n = 21, mean = 0.184 μg/g ww) or pike-perch Sander lucioperca (n=9, mean = 0.205 μg/g ww) respectively. Significantly lower values were measured in the muscle of the piscivorous pike Esox lucius (n = 25, mean = 0.135 μg/g ww) in which a strong correlation between fish age and Hg content did not occur. In addition the muscle/liver ratio of Hg in pike was significantly lower compared to the other fish species, which points to a different Hg metabolism in pike, maybe under the specific saline alkaline conditions of this lake.

Determination of total and bioavailable heavy and trace metals in South African commercial herbal concoctions using ICP-OES

In South Africa, the use of commercial herbal concoctions is becoming very popular. However, due to lack of Good Manufacturing Practices there is a possibility of heavy metal contamination in these commercial herbal concoctions. The aim of this investigation was to screen for heavy metal and trace elements in commercial herbal concoctions used in traditional medicine to treat various kinds of ailments in South Africa. This is the first investigation in which metal concentrations in commercial herbal concoctions was measured. Fourteen herbal concoctions were obtained from traditional herbal (muthi) shops and were subjected to analysis for total and bioavailable metal concentrations using Inductively Coupled Plasma-Optical Emission Spectrophotometry (ICP-OES). Of all the concoctions tested only Vusa umzimba and Sejeso herbal mixture contained high amounts of Cd (2.2 and 0.6mg/kg) respectively, exceeding the safety limit of 0.3mg/kg (WHO, 1998). Vusa umzimba also exhibited high amounts of bioavailable Cd (1.2mg/kg) thereby making it unsafe for human consumption. Surprisingly very high amounts of Hg were detected in Ingwe muthi mixture and Sejeso herbal mixture (14.9 and 12.3mg/kg) respectively. These by far exceeds the weekly allowance limit of 2μg/kg given by WHO/UN committee (2007). Relatively high amounts of Pb were found in Sejeso herbal mixture. The levels of bioavailable metals detected in this study raise concerns, not only for consumer safety, but also the quality of herbal concoctions available as part of the traditional medicinal practice in South Africa.

Atmospheric Particle Bound Mercury Hg(p) Concentrations and Amounts in Total Suspended Particulates and Dry Deposition at an Industrial and Wetland Sampling Sites in Taiwan

The focus of this study is to observe the seasonal variations of particulate bound mercury Hg(p) concentration and amount of Hg(p) (ng/g) in total suspended particulates (TSP) and dry deposition at two (industrial and wetland) characteristic sampling sites in Taiwan, during the years 2009–2010. Concentrations of Hg(p) from each sample (quartz filter, overhead projection film) were analyzed by a direct Hg(p) analyzer DMA-80. Approximately 30 mg of the filter sample was loaded directly into the DMA-80 and analyzed. The results indicated that the mean highest Hg(p) in TSP (expressed in ng/m3) and dry deposition (expressed in ng/m2/min) both occurred at the industrial site (Quan-xing) while the corresponding mean lowest Hg(p) concentrations occurred at the wetland site (Gao-mei). Also, the mean highest amount of Hg(p) (expressed in ng/g) in TSP and dry deposition occurred at the industrial site (Quan-xing), while the mean lowest amount of Hg(p) occurred at the wetland site (Gao-mei). Metal products manufacturing and heavily loaded traffic during weekdays were possible sources responsible for the high concentrations of Hg(p) observed at Quan-xing (industrial) sampling site.

Spectroscopic characterization of Cicer arietinum metallothionein 1

The plant metallothioneins differ distinctively from other metallothionein families with respect to the cysteine distribution patterns, the presence of aromatic amino acids in most and histidine in some forms, as well as long cysteine-free amino acid stretches between cysteine-rich regions. Although known for more than 25 years, research activity on plant metallothioneins has been low increasing only in the past few years. In the following, we will present the first characterization of Cicer arietinum (chickpea) MT1. In this root-specific protein two cysteine-rich regions with six cysteine residues each are separated by a 42 amino acids long linker region. A synthetic gene encoding MT1 was designed, cloned into a suitable vector, and the protein was over-expressed in Escherichia coli. We could show, that MT1 has the ability to coordinate up to five Zn 2+ or Cd 2+ ions and even higher amounts of Hg 2+. According to titration experiments pH-dependent zinc– and cadmium–thiolate cluster stability in MT1 is considerably lower than in vertebrate metallothioneins. The approximate contribution of secondary structural elements to the overall structure was assessed with circular dichroism and infrared spectroscopy. Hypothetical metal–thiolate cluster structures will be presented.

Residual mercury content and leaching of mercury and silver from used amalgam capsules

Objective: The objective of this investigation was to carry out residual mercury (Hg) determinations and toxicity characteristic leaching procedure (TCLP) analysis of used amalgam capsules. Methods: For residual Hg analysis, 25 capsules (20 capsules for one brand) from each of 10 different brands of amalgam were analyzed. Total residual Hg levels per capsule were determined using United States Environmental Protection Agency (USEPA) Method 7471. For TCLP analysis, 25 amalgam capsules for each of 10 brands were extracted using a modification of USEPA Method 1311. Hg analysis of the TCLP extracts was done with USEPA Method 7470A. Analysis of silver (Ag) concentrations in the TCLP extract was done with USEPA Method 6010B. Results: Analysis of the residual Hg data resulted in the segregation of brands into three groups: Dispersalloy™ capsules, Group A, retained the most Hg (1.225 mg/capsule). These capsules were the only ones to include a pestle. Group B capsules, Valliant PhD™, Optaloy™ II, Megalloy™ and Valliant Snap Set™, retained the next highest amount of Hg (0.534–0.770 mg/capsule), and were characterized by a groove in the inside of the capsule. Group C, Tytin™ regular set double-spill, Tytin FC™, Contour™, Sybraloy™ regular set, and Tytin™ regular set single-spill retained the least amount of Hg (0.125–0.266 mg/capsule). TCLP analysis of the triturated capsules showed Sybraloy™ and Contour™ leached Hg at greater than the 0.2 mg/l Resource Conservation and Recovery Act (RCRA) limit. Significance: This study demonstrated that residual mercury may be related to capsule design features and that TCLP extracts from these capsules could, in some brands, exceed RCRA Hg limits, making their disposal problematic. At current RCRA limits, the leaching of Ag is not a problem.