Cold Vapor Atomic Absorption Spectrometry Research Articles

Electrochemical sensing of Pb2+, Cu2+, and Hg2+ by an aminoclay-based porous covalent organic polymer/ multi-walled carbon nanotubes modified glassy carbon electrode

We present a novel electrochemical sensor for the simultaneous detection of Lead (Pb2+), Copper (Cu2+), and Mercury (Hg2+) ions in seafood samples using differential pulse anodic stripping voltammetry (DPASV) technique. The sensor incorporates an aminoclay-based porous covalent organic polymer (AC-PCOP) derived from the polymerization of aminoclay and 1,3,5-benzenetricarboxylic acid (trimesic acid). To enhance conductivity, the AC-PCOP is combined with multi-walled carbon nanotubes (MWCNTs) and utilized for modifying the surface of the glassy carbon electrode (GCE). The AC-PCOP was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and infrared spectroscopy (IR). These analyses confirmed the presence of a hierarchical architecture in the AC-PCOP, which exhibited a spherical shape. The proposed modifier facilitates the deposition-stripping process and electron diffusion between electrolyte and heavy metal ions. Optimized conditions yielded limit of detections (LODs) of 0.0006, 0.0016, and 0.0003 nM, with linear ranges from 0.002 to 1000 nM, 0.005 to 1000 nM, and 0.001 to 1000 nM for Pb2+, Cu2+, and Hg2+, respectively. The sensor successfully measured these ions in seafood samples. Control experiments and validation were performed using cold vapor atomic absorption spectrometry (CVAAS) to determine the ions in the chosen food samples.

Microelements, Fatty Acid Profile, and Selected Biomarkers in Grass Carp (Ctenopharyngodon idella) Muscle Tissue: Seasonal Variations and Health Risk Assessment

AbstractThe study assesses associations between microelement levels, fatty acid composition, and oxidative stress markers in grass carp muscle in the summer and autumn seasons. Additionally, various factors were considered, including the estimated daily intake (EDI), target hazard quotient (THQ), total THQ (TTHQ), and metal pollution index (MPI), to evaluate potential health risks for consumers. The microelements (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Ni, Pb, Se, Sr, and Zn) were determined using inductively coupled plasma optical emission spectrometry (ICP-OES), and total mercury was determined using cold-vapor atomic absorption spectroscopy (CV-AAS). Fatty acid profiling was realized using gas chromatography (GC) detection with a flame ionization detector (FID). The overall tendency of microelement levels was as follows: Fe > Zn > Al > Sr > Ba > Ni > Se > Cr> Cu > Mn > Pb > As > Li > Hg; <LOQ (below limit of quantification): Cd, and Co. The correlation analysis between concentrations of trace elements (Al, Ba, Cr, Cu, Mn, Li, Sr, Zn, and Hg) and the fatty acids (C16:0, C16:1, C18:1n9c, C18:2n6c, C20:4n6c, EPA, and DHA), as well as between Al, Ba, Fe, or Hg and oxidative stress markers (superoxide dismutase—SOD, glutathione peroxidase—GPx, or total antioxidant status—TAS), revealed statistically significant interactions in different seasons. THQ values were lower than 1; TTHQ values ranged from 0.27 to 0.76. The main toxic elements forming TTHQ were Hg and Ni (49%). The calculated health risk assessment indices indicate a low concentration of observed elements and low risks associated with the consumption of grass carp muscle from the tested location, although concentrations and THQ of mercury and nickel may be of slight concern.

Development and initial evaluation of a combustion-based sample introduction system for direct isotopic analysis of mercury in solid samples via multi-collector ICP-mass spectrometry

High-precision isotopic analysis of mercury (Hg) using multi-collector ICP-mass spectrometry (MC-ICP-MS) is a powerful method for obtaining insight into the sources, pathways and sinks of this toxic metal. Modification of a commercially available mercury analyzer (Teledyne Leeman Labs, Hydra IIc – originally designed for quantification of Hg through sample combustion, collection of the Hg vapor on a gold amalgamator, subsequent controlled release of Hg and detection using cold vapor atomic absorption spectrometry CVAAS) enabled the system to be used for the direct high-precision Hg isotopic analysis of solid samples using MC-ICP-MS – i.e., without previous sample digestion and subsequent dilution. The changes made to the mercury analyzer did not compromise its (simultaneous) use for Hg quantification via CVAAS. The Hg vapor was mixed with a Tl-containing aerosol produced via pneumatic nebulization, creating wet plasma conditions, and enabling the use of Tl as an internal standard for correction of instrumental mass discrimination. Accurate and precise (0.10 ‰ 2SD, δ202Hg, n = 5) results were obtained for an in-house standard solution of Hg (20 ng Hg sample intake). Initial validation relied on the successful analysis of two solid certified reference materials of biological origin (BCR CRM 464 Tuna fish and NRC-CNRC TORT-3 Lobster hepatopancreas). It was shown that instrumental mass discrimination can be adequately corrected for by relying on the use of an aqueous Hg standard solution (NIST SRM 3133), without the need of matrix-matching. The novel setup developed thus allows for direct high-precision isotopic analysis of Hg in solid samples, thus enhancing the sample throughput. It is also suited for samples for which low amounts are available only and/or that are characterized by low Hg concentrations.

Blood Concentration of Macro- and Microelements in Women Who Are Overweight/Obesity and Their Associations with Serum Biochemistry.

Risk elements in blood matrices can affect human health status through associations with biomarkers at multiple levels. The aim of this study was to analyze 15 macro- and microelements in the blood serum of women with overweight (BMI of ≥25 kg/m2) and obesity (BMI of ≥30 kg/m2) and to examine possible associations with biochemical, liver enzymatic parameters, and markers of oxidative stress. Based on the power calculation, the study involved women (in the postmenopausal stage) with overweight (n = 26) and obesity (n = 22), aged between 50-65 years. Multifrequency bioelectrical impedance analysis was used to measure body composition parameters. Concentrations of elements were determined by inductively coupled plasma optical emission spectrometry, and Hg was measured using cold-vapor atomic absorption spectroscopy. Individuals with obesity, as indicated by a higher BMI, percentage of body fat, and visceral fat area, had elevated serum levels of Ca, Mg, Fe, Al, Sr, Pb, and Hg. Concentrations of Al, Cu, K, Sb, Zn, and Pb significantly affected biochemical and liver function markers in women with overweight or obesity. Elements such as Cu and Al were associated with increased total cholesterol. The correlation analysis between total antioxidant status and Cu, Al, and Ni confirmed associations in both groups. Our findings underscore the importance of addressing excess body weight and obesity in relation to risk elements. The results of the research could be beneficial in identifying potential targets for the treatment or prevention of comorbidities in people with obesity.

Participatory assessment of pollution and health risk in artisanal and small-scale gold mining communities in Colombia

The predominantly Afro-descendant communities of Yolombó and La Toma depend on the region's rich natural resources through livelihoods such as farming, fishing, and artisanal and small-scale gold mining (ASGM). Previous studies of the region have identified elevated levels of mercury in several surface and groundwater sites. Furthermore, recent regional studies have identified human health risks associated with mercury exposure through hazard quotient (HQ) modeling and global sensitivity and uncertainty analysis (GSUA). However, there has yet to be a comprehensive analysis of water pollution involving different metals and metalloids potentially present in ASGM-influenced areas to estimate the associated environmental and human health impacts. In this study, we employed a participatory methodology to identify sources of exposure in Colombian ASGM communities through surveys, consumption diaries, and interviews. We then screened for relevant metals and metalloids through groundwater analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES) and cold vapor atomic absorption spectrometry (CV-AAS). Furthermore, we calculated water pollution indices, including heavy metal pollution index (HPI), degree of contamination (Cd), heavy metal toxicity load (HMTL) and heavy metal evaluation index (HEI). Finally, we quantified human health risks related to groundwater consumption through the HQ and hazard index (HI). Although the groundwater assessed in this study generally meets United States and Colombian regulatory standards, heightened Fe, Mn, and Al levels were observed. The pollution indices generally agreed that three of the sites tested showed medium to high pollution levels. The HI showed that the combined effect of all metals tested did not substantiate risk for most participants. However, the HI of one participant, a child, exceeded the 1.00 threshold. Furthermore, the presence of Pb, despite meeting regulatory limits, necessitates further scrutiny due to its substantial impact on pollution and human health hazard indices.

Background levels of heavy metals in the water of Khadzhibey estuary

In the Odesa region, heavy metal contamination of fishery water bodies is a pressing problem. The accumulation of heavy metals in fish depends on the physiological and biochemical activity of the organism and the physical and chemical parameters of the water body. Most heavy metals enter the fish's body through the gills, skin, and digestive organs. Copper, zinc, and plumbum accumulate in the skin, gills, and liver, while cadmium and mercury accumulate in the kidneys. The level of heavy metal pollution in the water of the Khadzhibey estuary was measured and determined in 2022–2023. The following methods were used to determine the content of heavy metals in water: atomic emission spectroscopy using an EMAS-200 CCD instrument to determine cadmium, copper, zinc, and plumbum; cold vapor atomic absorption spectroscopy using the “Julia-2M” method to determine the content of mercury. Toxicological studies of water were carried out in the water hygiene and ecology laboratory of the Ukrainian Research Institute of Transport Medicine and at the Department of Veterinary Hygiene, Sanitation, and Expertise of Odesa State Agrarian University. The study found that the content of heavy metals in the water of the Khadzhibey estuary is not constant and fluctuates depending on the season. The maximum levels of heavy metals are observed in summer (plumbum and cadmium) and autumn (zinc, copper and mercury). It was found that cadmium, plumbum, copper, and mercury content does not exceed the maximum permissible levels for marine fisheries. The zinc content in the water of the Khadzhibey estuary exceeds the maximum permitted concentration by 2.65%. The zinc content in the studied water samples is a stress factor affecting the meat quality of common carp (Cyprinus carpio) and round goby (Neogobius melanostomus).

Trace Metals Distribution in Tissues of 10 Different Shark Species from the Eastern Mediterranean Sea

As long-living apex predators, sharks tend to bioaccumulate trace metals through their diet. The distribution of Al, As, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, V, Zn and Hg in different tissues (muscle, liver, heart, gills and gonads) of large-size (58–390 cm) sharks, some of which rare, of the eastern Mediterranean Sea was studied. Trace metals analyses in samples originating from ten different Chondrichthyes species were performed by inductively coupled plasma–mass spectrometry (ICP-MS) and Cold Vapor Atomic Absorption Spectrometry (CVAAS) for Hg. Data on trace metal levels are for the first time reported herewith for the species O. ferox and H. nakamurai. Higher median concentrations of trace metals were generally determined in the liver. The concentrations of Hg, Cs and As in the muscle increased proportionally with body length. Statistically significant differences between sexes were recorded for Hg, Cr, Ni and As (p = 0.015) in the muscle tissues of P. glauca. Muscle tissue Hg concentrations exceeded the EU maximum limit (1 μg g−1 wet weight) in 67% of the individuals sampled, with the highest concentrations detected in O. ferox and S. zygaena, whereas regarding Pb (limit 0.30 μg g−1 ww), the corresponding percentage was 15%. Arsenic concentrations were also of concern in almost all shark tissues examined.

Accumulation of mercury in muscle of orange-spotted spinefoot(Siganus guttatus Bloch, 1787) by age and season in the coastal Quang Binh

Orange-spotted spinefoot (Siganus guttatus) is not only a fish with high economic value, rich in nutrients, but also popular with people for consumption. This research was carried out from November 2021 to May 2022, in the coastal and estuaries of Quang Binh province. A total of 60 samples of orange-spotted spinefoot were collected by age group, wet season, and dry season to analyse the accumulation of mercury (Hg) in their muscles. The Hg concentration was analysed by cold vapour atomic absorption spectroscopy. Research results showed a strong correlation between the length and weight of fish both in the wet and dry seasons. The age group has a strong influence on the accumulation of Hg in their muscles, the older fish group has a higher aggregation of Hg than the younger fish group. Although the average value of Hg concentration in the muscle of orange-spotted spinefoot in the dry season is higher than in the wet season, analysis results of “Tukey’s HSD test” showed that there was no significant difference.

A flow-batch lab-in-syringe foam microextraction platform for the simultaneous preconcentration and in situ membraneless gas-liquid separation of mercury prior to cold vapor atomic absorption spectrometry

Herein, the proof-of-concept of a novel lab-in-syringe (LIS) foam microextraction platform is presented as a front-end to cold vapor atomic absorption spectrometry (CVAAS) for the simultaneous preconcentration and membraneless gas-liquid separation (GLS) of inorganic mercury in biological samples. The proposed method is based on the on-line formation of the ammonium pyrrolidine dithiocarbamate complex with mercury that was retained in the pores of polyurethane foam immobilized on the piston of the LIS system. Metal complex elution and in situ mercury vapor generation are accomplished inside the microsyringe in a flow-batch format, while the separation of vapor species is achieved via the membraneless GLS found at the top of the syringe’s barrel. Under optimized operation conditions, for 90 s preconcentration time, the limit of detection was 0.02 μg L−1 and the repeatability (RSD) was 3.8% (at the 0.5 μg L−1 concentration level), within a working range extending up to 4.0 μg L−1. The practicality of the novel manifold was demonstrated using the Blue Applicability Grade Index, while the accuracy of the method was evaluated using certified reference materials and spiked samples.

The effect of selenium co-ingestion on mercury bioaccessibility in contaminated fish of the Amazon region

Mercury (Hg) is a toxic element that contaminates humans by consuming fish with high concentrations due to biomagnification in the food chain. This situation primarily impacts the riverside population in the Amazon region, as fish is their staple food. The interaction between selenium (Se) and Hg is well known due to their respective conceptual Pearson (soft-soft) characteristics. However, there needs to be more understanding of the impact of Se co-ingestion on Hg bioaccessibility. This scenario has prompted the investigation into the effects of consuming Se-rich food on the potential bioaccessibility of Hg when simultaneously ingesting contaminated fish. Cold vapor atomic absorption spectrometry (CV-AAS) measured Hg, and a hydride generator (HG-AAS) was used for Se. The results indicated that the piscivorous species Cichla sp. (Tucunaré fish) exhibited a Hg concentration over twice the limit established by the European Commission: 2.94 ± 0.21 μg g−1 for raw fish and 2.64 ± 0.16 μg g−1 for cooked fish. Concomitant ingestion of beans can reduce the potential bioaccessibility of Hg by 42% (68.4 to 25.8), and Brazil nuts co-ingestion can be reduced by 45% (68.4 to 23.1). However, due to the high fish consumption in the riverside population's diet, the Hazard Index (HI) and Target Hazard Quotient (THQ) values, including beans and Brazil nuts, exceeded the safe limit, even though THQ had decreased by 55%, and 66% with adding beans and Brazil nuts, respectively. These findings underscore the significant potential of Se in reducing Hg bioaccessibility through co-ingestion of foods containing this element. Additionally, it highlights the importance of considering regional dietary habits when assessing potential health risks. The results also sound like a warning about the food safety of the local communities.

Identification and Characterization of Mercury Contamination in Vegetables and Herbs Cultivated on a Commercial Vertical Indoor Farming System with Light-Emitting Diode Lighting: Unveiling an Unusual Food Safety Risk of Some Improperly Manufactured High-Density Agricultural Production Systems.

Artificial grow lights, such as light-emitting diodes (LEDs) and fluorescent grow lights, are commonly used in modern day indoor farming, citing advantages in energy efficiency and a higher controlled environment. However, the use of LEDs poses a risk in mercury contaminations as a result of its production process, specifically LEDs with polyurethane encapsulates that were traditionally produced using mercury resins as a catalyst. A total of 10.0 ppm of mercury was detected in a curly kale sample harvested from an indoor hydroponic vegetable farm, exceeding Singapore Food Regulation's limit of 0.05 ppm. Vegetables, farming inputs, and surface swabs from the affected farm were analyzed using wet acid digestion followed by cold vapor atomic absorption spectroscopy analysis. The investigation found high concentrations of mercury in the LED encapsulant, and the encapsulant material was identified to be polyurethane by Fourier transform infrared spectroscopy and pyrolysis-gas chromatography-mass spectrometry analysis, indicating the source of mercury contamination to be the LED polyurethane encapsulant.

Analytical method for the determination of Hg from the organs of some terrestrial plants using cold vapor atomic absorption spectrometry

The aim of the study was to develop a new method for mercury determination from plants grown on mercury-polluted soils as well as to evaluate the mobility and bioavailability of mercury in the soil and its transfer to different plant organs (root, stem, leaves) from three different plants, such as mustard (Sinapis alba), thyme (Thymus serpyllum) and wild thyme. A cold vapor atomic absorption spectrometry (CV-AAS) method for the detection of mercury in plants was developed. The developed method was validated in the laboratory and was verified using two different certified reference materials (CRMs) type matrices, namely: NIST 1515 Apple Leaves and BCR-482 Lichen.

Mercury Determination in Fish Using Cold Vapour-Atomic Absorption Spectrometry (CV-AAS) with Sodium Borohydride (NaBH4) as the Reductor

Marine fish can potentially accumulate heavy metal pollutants, such as mercury, from anthropogenic activities that can harm people who consume it. Marine fishes like Bandeng fish (Chanos chanos), Banjar fish (Rastrelliger kanagurta), Bawal Hitam fish (Parastromateus niger), Selar Kuning fish (Atule mate), Tenggiri fish (Scomberomorini), and Tuna fish (Thunnini) are consumed a lot by people in Bandung City. All these fish were analyzed using the CV-AAS method with the United States – Environment Protection Agency (USEPA, 2006), and the reducing agent was replaced by stannous (II) chloride with sodium borohydride. Variations in the sample preparation process include drying the sample using an oven and freeze dryer. SEM-EDX in the frozen-dried samples shows that the fibbers’ morphology is intact, while the fibbers are damaged in the hot-dried samples. During characterization using FTIR, there is a slight shift in wave number. The mercury concentrations obtained from every sample were below 0.5 mg/kg based on the Indonesian National Standard (SNI) 2009 standard for total mercury in fish. Therefore, it can be concluded that the samples are safe to be consumed. Validation methods showed that 0.3% sodium borohydride as the reductor can be used to analyze mercury and replace stannous (II)chloride. However, further studies are needed to determine the optimal concentration of sodium borohydride (NaBH4) in the marine fish samples as a reduction agent.

Distribution of Mercury in Drained Peatlands as the Effect of Secondary Transformation of Soil Organic Matter

Peat organic soils play a major role in the accumulation of soil organic matter (SOM) and the mercury (Hg) cycle. Large mercury resources in peatlands can be a source of methylmercury for many decades and centuries, even if deposition is significantly reduced. The organic matter of peatland soils drained for agricultural use is subject to secondary transformation, which may affect the accumulation and resources of mercury. The aim of our work is to assess the secondary transformation of organic matter in the soils of drained peatlands of the temperate climate zone and to examine whether it affects mercury resources and profile distribution in organic soils. Field research was conducted in peatlands located in eastern Poland. In the present study, evaluation of secondary transformations occurring after drainage was based on observations of soil morphological characteristics, physical and chemical properties as well as fractional composition of organic matter of the identified soil horizons (to depth 70 cm). Standard cold vapor atomic absorption spectrometry (CV-AAS) was used to measure the total mercury content. In our research, we found a significant effect of the secondary transformation of organic matter occurring in drained peatlands of the temperate climate zone on the total mercury content and stock in soils. The highest content and differentiation of mercury occurred in murshic horizons (up to a maximum depth of 43 cm). The average mercury content of the distinguished soil horizons is grouped in the following series (in μg kg−1): M1 (212.0) > M2 (182.8) > M3 (126.3) > Pt (84.9). The mercury stock, up to a depth of 70 cm in the tested soils, ranged from 17.5 to 39.6 mg m−2. As much as 82.2% of soil mercury was found in the upper murshic horizons. We found strong correlations between soil properties characteristically variable in the secondary transformation process and total mercury content. The increased content of humic substances in murshic horizons caused a significant increase in the total mercury content. Our research is of great importance for soil monitoring, as the amount of determined mercury was greatly influenced by the depth of sampling (up to 25 cm). The results of the research should be taken into account when planning the restoration of peatlands of the temperate climate zone. There is a potential risk that elevated mercury concentrations in the upper murshic horizons may be a source of methylmercury for a long period of time. In peat soils with a high concentration of mercury, the risk of contamination with this toxic metal should be determined before re-irrigation.

Spatial distribution of Hg in Pra River Basin, Southwestern Ghana using HF acid combination method

The study assessed the spatial distribution of total mercury (THg) in soils, sediments, mining wastes, and Au-rich Hg-contaminated tailings from artisanal and small-scale gold mining (ASGM) from Offin, Lower and Upper Pra, Birim, and Anum Rivers, Pra River Basin, Southwestern Ghana. THg measurement using Cold Vapor Atomic Absorption Spectrometry (CVAAS) after acid digestion with HNO3/HCl/HF and k0-INAA, as a reference method, and both provided comparable results. A digestion method, HNO3/HClO2/H2SO4 acid mixture before CVAAS provided lower results, which indicates that the use of HF is of fundamental importance in THg analysis based on acid digestion and its omission may significantly underestimate the presence of Hg in soils and sediments. THg in soils, sediments, Au-rich Hg-contaminated tailings, and mining wastes from the river basin were liberated into a solution for measurement using HNO3/HCl/HF. The study revealed Offin and Lower Pra Rivers showed high distribution (ranges; mg Hg kg-1) of THg in soils (103-770) and sediments (0.20-20.8), respectively; Upper Pra and Anum rivers showed the lowest THg in soils (2.20-3.20) and sediments (0.004-0.02), respectively. About 76.0% of THg in sediments was lower than the USEPA guideline of 0.2mg Hg kg-1. The highest mean THg (mg Hg kg-1) in Au-rich Hg-contaminated tailings (1673 ± 4.8, n = 4) and mining wastes (17.3-21.5) were from the river Offin. The study showed Offin (Dunkwa-on-Offin site 1) and Lower Pra (Beposo Township) rivers are Hg hotspots that need attention.

Study of mercury release in dental amalgam wearers by measuring salivary and urinary mercury

Background. Mercury amalgam remains the most effective and least expensive dental filling material. Mercury is considered by the World Health Organization (WHO) as one of the ten chemicals or groups of chemicals that are extremely concerning for public health. The aim of our study is to assess exposure to mercury from dental amalgams through the measurement of salivary and urinary mercury. Population and methods. This is a prospective, analytical study carried out at the National Toxicology Center of Algiers during the year 2004. The study included 48 subjects with dental amalgams and 12 subjects without amalgams. Mercury levels in saliva and urine were measured by cold vapor atomic absorption spectrometry using the "Flow Inject Mercury System". Results. Compared to other studies, the urinary mercury values in our study are relatively high. This observation is also true for our controls. For salivary values, our subjects have levels (after chewing) that remain within the same range. The comparison of urinary and salivary means shows a significant difference between subjects with three or more amalgams and controls. There is also a significant correlation between the number of fillings and salivary concentrations. Among all amalgam bearers, there is no significant correlation between urinary and salivary concentrations. Elevated levels were noted in our controls compared to foreign studies, indicating probable general exposure (food, atmosphere, etc.). Conclusion. There is a real exposure to mercury from dental amalgams, but is this exposure harmful to the health of the bearers? This risk remains "acceptable" as long as we stay below the accepted limits. It is necessary to protect at-risk groups (pregnant and breastfeeding women, children, and adolescents) from this exposure.

Mercury in Selected Abiotic and Biotic Elements in Two Lakes in Poland: Implications for Environmental Protection and Food Safety

Mercury, which tends to bioaccumulate and biomagnify in aquatic food webs, poses a potential health risk to wildlife and to consumers of predatory fish in particular. Its concentration in biota can be high even at low environmental concentrations. Therefore, the aim of this study was to determine mercury in both abiotic (water and sediment) and biotic elements (common reed (Phragmites australis) and fish: pike (Esox lucius), bream (Abramis brama) and roach (Rutilus rutilus)) in the context of assessing the pollution of two lakes in Poland and the safety of fish consumers. The possibility of Hg biomagnification in fish was also considered. Mercury was determined by means of cold vapor atomic absorption spectrometry (CVAAS). The concentrations of Hg in water and bottom sediments of Lake Ińsko were lower than in Lake Wisola. In the bottom sediments of both lakes, a positive correlation was found between the Hg content and organic matter. The concentration of mercury in the organs of common reed did not exceed 0.017 mg/kg dry weight (dw), and its distribution can be presented as follows: root > leaves > stems > rhizomes. In fish organs from both lakes, the average mercury content did not exceed 0.086 mg/kg of wet weight (ww) and in most cases it was the highest in pike. Higher values were only observed in the muscles and skin of roach. This indicates a lack of biomagnification in the relationships between planktivorous-predatory and benthivores-predatory fish. Based on the maximum levels of mercury in fish and the calculated parameters, i.e., estimated daily intake (EDI), target hazard quotient (THQ) and tolerable weekly intake (TWI), the muscles of the examined fish were found to be safe for consumption. The average dietary exposure to total mercury (THg) and methylmercury (MeHg) was below 0.3% of the TWI.

Quality of Phosphate Rocks from Various Deposits Used in Wet Phosphoric Acid and P-Fertilizer Production.

Phosphate rocks (PRs) play a crucial role in ensuring the availability of phosphorous for the world's food needs. PRs are used to manufacture phosphoric acid in the wet process as well as P-fertilizers. The chemical and mineralogical compositions of PRs from Djebel Onk (Algeria), Khneifiss (Syria), Negev (Israel), Bou Craa (Morocco), and Khouribga (Morocco) are discussed in this study. PRs were characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), cold vapor atomic absorption spectrometry (CVAAS), ion chromatography (IC), and X-ray diffraction (XRD), as well as gravimetric and potentiometric methods. All PRs were mainly composed of CaO, P2O5, SiO2, F, SO3, Na2O, MgO, Al2O3, Fe2O3, SrO, and K2O at the level of wt.%. The P2O5 content accounted for 28.7-31.2%, which indicates that these are beneficial rocks to a marketable product. The degree of PR purity expressed by the minor elements ratio index (MER index) varied from 2.46% to 10.4%, and the CaO/P2O5 weight ratio from 1.6 to 1.9. In addition, the occurrence of trace elements such as As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Ti, V, U, and Zn, as well as Cr(VI) and Cl ions at the level of mg∙kg-1 was found. Since PRs will be used to produce P-fertilizers, their composition was compared with the regulatory parameters set up by EU Regulation 2019/1009 related to the heavy metals (As, Cd, Pb, Ni, Hg, Cu, Zn) and Cr(VI) contents in inorganic fertilizers. The heavy metals and Cr(VI) content in all PRs did not exceed the limit values. XRD analysis revealed that fluorapatite, hydroxyapatite, carbonate fluorapatite, and carbonate hydroxyapatite were the dominant minerals. The accuracy and precision of the used methods were evaluated by analysis of standard reference materials (SRM) for Western Phosphate Rock (NIST 694). The recovery was 85.3% for U and 109% for K2O, and the RSD ranged from 0.67% to 12.8%.

Elution behavior of mercury in desulfurization gypsum produced in a coal-fired power plant

Batch and semi-batch elution tests were conducted to determine the elution pattern and dissolvable amount of mercury in desulfurization gypsum produced in a coal-fired power plant. Two gypsum samples obtained from double-contact-flow-type desulfurization equipment were used. Chemical forms of mercury in gypsum were identified by temperature programmed desorption–cold vapor atomic absorption spectroscopy. The elution behavior of mercury varied significantly with the testing method. In the batch elution test, an industrial standard method, mercury eluted into the water rapidly and was then adsorbed by gypsum. This behavior was kinetically simulated with the sequential elution and adsorption of mercury, showing the maximum elution peak. In contrast, in the semi-batch method, the adsorption phenomenon was negligible, and the ultimate amount of eluted mercury could be determined. Thus, the semi-batch method is more accurate for evaluating mercury elution from desulfurization gypsum.

Determination of Heavy Metal Residues in Tropical Fruits near Industrial Estates in Rayong Province, Thailand: A Risk Assessment Study

This study determined the extent of heavy metal contamination of local fruit in Rayong, Thailand, an area where an industrial base is adjacent to agricultural areas. Dietary exposure to agricultural products grown in contaminated areas can cause multiple adverse effects to the human body. In order to avoid such undesirable effects, concentrations of heavy metals [arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn)] were investigated in popular tropical fruits from three districts of Rayong, namely Wang Chan, Klang and Mueang. The levels of heavy metals were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and cold vapor-atomic absorption spectrometry (CV-AAS). Levels of the six heavy metals in sampled fruits (durian, jackfruit, pineapple, rambutan, long kong, and mangosteen) were in the range of 0.0004-6.7095 mg/kg; 16.7% of fruit samples exceeded maximum permissible limits of Pb. Based on health risk assessments, values of estimated daily intake (EDI) were less than those of maximum tolerable daily intake. However, for non-carcinogenic risks, high hazard index (HI) values were found in some markets while for carcinogenic risks (CRs), CR values of three fruits (durian, jackfruit, and mangosteen) exceeded acceptable levels. Therefore, long-term fruit consumption could impact health of local consumers. These results provided insight into the need for regular monitoring of heavy metal concentrations in potentially contaminated fruits and for prevention of its potential effects.