Concentrations Of Toxic Metals Research Articles

Treatment of Acid Mine Water from the Breiner-Băiuț Area, Romania, Using Iron Scrap

Acid mine drainage (AMD) forms in mining areas during or after mining operations cease. This is a primary cause of environmental pollution and poses risks to human health and the environment. The hydrographic system from the Maramureș mining industry (especially the Baia Mare area) was heavily contaminated with heavy metals for many years due to mining activity, and after the closing of mining activity, it continues to be polluted due to water leaks from the abandoned galleries, the pipes, and the tailing ponds. The mineralization in the Băiuț area, predominantly represented by pyrite and marcasite associated with other sulfides, such as chalcopyrite, covelline, galena, and sphalerite, together with mine waters contribute to the formation of acid mine drainage. The Breiner-Băiuț mining gallery (copper mine) permanently discharges acidic water into the rivers. The efficiency of iron scrap (low-cost absorbent) for the treatment of mine water from this gallery was investigated. The treatment of mine water with iron shavings aimed to reduce the concentration of toxic metals and pH. Mine water from the Breiner-Baiut mine, Romania, is characterized by high acidity, pH = 2.75, and by the association of many heavy metals, whose concentration exceeds the limit values for the pollutant loading of wastewater discharged into natural receptors: Cu—71.1 mg/L; Zn—42.5 mg/L; and Fe—122.5 mg/L. Iron scrap with different weights (200 g, 400 g, and 600 g) was put in contact with 1.5 L of acid mine water. After 30 days, all three treatment variants showed a reduction in the concentrations of toxic metals. A reduction in Cu concentration was achieved below the permissible limit. In all three samples, the Cu concentrations were 0.005 for Sample 1, 0.001 for Sample 2, and <LOQ for Sample 3. The Zn concentration decreased significantly compared to the original mine water concentration from 42.5 mg/L to 1.221 mg/L, 1.091 mg/L, and 0.932 mg/L. These values are still above the permissible limit (0.5 mg/L). The Fe concentration increased compared to the original untreated water sample due to the dissolution of iron scrap. This research focuses on methods to reduce the toxic metal concentration in mine water, immobilizing (separating) certain toxic metals in sludge, and immobilizing various compounds on the surface of iron shavings in the form of insoluble crystals.

Assessment of the relationship between vascular diseases and exposure to toxic metals

Aims: Understanding the factors in the etiology of vascular diseases is crucial for prevention. This study assesses the relationship between toxic metal exposure and vascular disease development. Methods: Blood samples from 41 healthy volunteers and 48 cardiovascular disease patients were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The participants' health data were obtained from hospital records. Results: ICP-MS results showed higher levels of As (5.97 µg/L), Cd (0.44 µg/L), Hg (0.48 µg/L), Pb (37.10 µg/L), Se (75.76 µg/L), Cu (1611.99 µg/L), Mn (14.55 µg/L), Co (0.14 µg/L), Mo (1.93 µg/L), and Ni (0.25 µg/L) in the experimental group. Conversely, Zn (557.0 µg/L), Cr (4.12 µg/L), and Sb (2.35 µg/L) levels were lower. Triglyceride (135.99 mg/dl), folate (8.77 ng/dl), and T3 (1.30 ng/dl) were higher, while HDL (44.13 mg/dl) was lower in the experimental group. Conclusion: These findings suggest a potential relationship between higher exposure to certain toxic metals and the development of vascular diseases. The higher concentrations of toxic metals in the blood of patients with vascular diseases underline the need for further research to confirm these associations and explore potential mechanisms.

Toxic metals and other elements in Svalbard reindeer: Establishing baselines and assessing non-invasive sampling for biomonitoring.

Pollutants emitted from all over the world may reach pristine areas, such as the Arctic. The Svalbard reindeer (Rangifer tarandus platyrhynchus) has been the subject of a few studies reporting toxic metal concentrations. However, these studies either date back a few decades or exclusively used non-invasive samples (e.g., faeces and fur), leaving us without an updated assessment of the concentrations in internal tissues and target organs. This study is the first to present the concentrations of the toxic metals mercury (Hg), cadmium (Cd), and lead (Pb) in both invasive and non-invasive samples from female Svalbard reindeer. The highest concentrations of both Hg and Cd were found in the kidneys (x̄=0.68μg/g and 16.3μg/g dw, respectively). The highest concentration of Pb was found in faeces (x̄=2.62μg/g dw), followed by liver (x̄=0.28μg/g dw). While both Cd and Pb concentrations in Svalbard reindeer were comparable to levels reported in other reindeer subspecies or circumpolar wildlife, Hg concentrations were lower than those reported in most other studies on reindeer. Conversely, Hg levels in Svalbard reindeer were still higher than levels reported in wildlife from central Europe, demonstrating the influence of long-range transport of Hg to the Arctic. By comparing the toxic metal concentrations in different sample types, we confirm a relationship between Hg concentrations in invasive and non-invasive samples, with faeces being the most promising proxy for soft tissue Hg concentrations. Consequently, future Hg biomonitoring efforts may be carried out with relatively simple sampling procedures and without sacrificing Svalbard reindeer.

Escherichia coli growing under antimicrobial gallium nitrate stress reveals new processes of tolerance and toxicity

Metals have been used throughout history to manage disease. With the rising incidence of antibiotic-resistant bacterial strains, metal-based antimicrobials (MBAs) have re-emerged as an alternative to combat infections. Gallium nitrate has shown promising efficacy against several pathogens. Although its main toxicity mechanisms have focused on oxidative stress and its “trojan horse” iron mimetic strategy, there are still many knowledge gaps in the full-systems response elicited to counteract its toxic effects, especially in non-acute toxicity models that evaluate longer exposure times. In this study, we explore the transcriptomic response profile of Escherichia coli K12 BW25113 when challenged to grow planktonically for 10 h in the presence of a sublethal inhibitory concentration of gallium nitrate. 581 genes were significantly up-regulated, and 791 down-regulated. Some of the affected biological systems identified in our analysis include iron homeostasis, sulfate metabolism, oxidative and nitrosative stress response, cysteine biosynthesis, anaerobic respiration, toxin-antitoxin interactions, and DNA repair. Altogether, this work provides a valuable snapshot of how E. coli acclimates to this MBA and expands the current knowledge of mechanisms of sensitivity and tolerance. This is a significant step in understanding how bacteria can adjust their physiology to coexist with sublethal concentrations of toxic metals.

A ten-year historical analysis of urban PM10 and exceedance filters along the Northern Wasatch Front, UT, USA.

The Great Salt Lake (Utah, USA) is reducing in size, which raises several ecological concerns, including the effect of an increasing area of dry playa exposed by the retreating lake. This study focuses solely on concerns about the toxicity of metals in the dust blowing off the playa. Although considerable efforts have been made to understand aeolian dust in urban areas along the Wasatch Front, located just east and south of the Great Salt Lake, there is still a need to consolidate existing research and to conduct a compositional analysis of the dust found in these urban areas. We investigated the dust reaching urban monitoring sites around the Great Salt Lake that are managed by the Utah Division of Air Quality. By analyzing historical data, we found that the decrease in the Great Salt Lake's surface area has not led to a statistically significant increase in dust events in urban areas. Windrose plots align with prior research, indicating that heightened dust levels in urban areas coincide with winds originating from the south or west, passing over identified playas and deserts such as the Milford Flats, Sevier Dry Lake, Tule Dry Lake, Great Salt Lake Desert, Dugway Proving Grounds, and the West Desert of Utah. Metallic compositional analysis of urban dust was used to evaluate potential health risks associated with the dust using the hazard quotient, air regional screening levels, and cancer risk methods. This analysis revealed no significant increase in concentrations of toxic metals. However, this is not to preclude a risk of dust-related health concerns, especially due to pre-existing arsenic and lead levels. SYNOPSIS: This study provides insights into dust-related health risks and environmental impacts in Utah, analyzing dust exposure from shrinking Great Salt Lake.

In Situ Phytoremediation of Mine Tailings with High Concentrations of Cadmium and Lead Using Dodonaea viscosa (Sapindaceae).

The waste generated during metal mining activities contains mixtures of heavy metals (HM) that are not biodegradable and can accumulate in the surrounding biota, increasing risk to human and environmental health. Plant species with the capacity to grow and develop on mine tailings can be used as a model system in phytoremediation studies. Dodonaea viscosa (L.) Jacq. is a shrub with wide geographical distribution and the ability to establish itself in mine tailings. The Sierra de Huautla Biosphere Reserve in Mexico contains a metallurgic district where mining activities have generated 780 million kg of waste with large concentrations of toxic heavy metals, mainly cadmium and lead. The present study evaluated the phytoremediation potential of D. viscosa in in situ conditions on soils contaminated with HMs (exposed) and reference sites (non-exposed) for one year. Also, the effects of cadmium (Cd) and lead (Pb) exposure in D. viscosa were analyzed via DNA damage (comet assay) morphological and physiological characters in exposed vs non-exposed individuals. The concentration of Cd and Pb was measured through atomic absorption spectrophotometry in the roots and leaves of plants. In total, 120 D. viscosa individuals were established, 60 growing in exposed and 60 in non-exposed soils. Exposed individuals of D. viscosa hyperaccumulated Cd and Pb in roots and leaves. At the end of the experiment, eight out of twelve characters under evaluation decreased significantly in HM-exposed plants in relation to individuals growing in non-exposed soils, except for stomatal index, stomatal coverage, and fresh leaf biomass. The micro-morphological and physiological traits of D. viscosa were not influenced by Cd and Pb bioaccumulation. In contrast, the bioaccumulation of Cd and Pb significantly influenced the macro-morphological characters and genetic damage; this last biomarker was 3.2 times higher in plants growing in exposed sites. The bioconcentration factor (BCF) of Cd and Pb in root and leaf tissue increased significantly over time. The mean BCF in root and leaf tissue was higher for Pb (877.58 and 798.77) than for Cd (50.86 and 23.02). After 12 months of exposure, D. viscosa individuals growing on mine tailing substrate showed that the total HM phytoextraction capacity was 7.56 kg∙ha-1 for Pb and 0.307 kg∙ha-1 for Cd. D. viscosa shows potential for phytoremediation of soils contaminated with Cd and Pb, given its capacity for establishing and developing naturally in contaminated soils with HM. Along with its bioaccumulation, biomass production, abundance, and high levels of bioconcentration factors, but without affecting plant development and not registering associated herbivores, it may incorporate HM into the trophic chain.

Trace metal accumulations in commercially important fish and crab species from impacted tropical estuary, India: implications on human health risk assessment.

Despite the beneficial role of aquatic food, bioaccumulation of trace metals can increase health risk for consumers. We conducted a comprehensive study to understand the levels of various trace metals (Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn and Mn) in fish (Nematalosa nasus, Gerres filamentosus, Arius arius, Gerres erythrourus, Sardinella fimbriata, Caranx ignobilis, Etroplus suratensis, Mugil cephalus, Sillago sihama, and Euryglossa orientalis) and crab (Portunus pelagicus and Scylla serrata) species collected from Netravathi-Gurupur estuary, India and evaluated the potential health risks to humans by measuring target health hazard (THQ), hazard index (HI), estimated daily (EDI) and weekly (EWI) intake and cancer risk (CR). The hierarchy of toxic metal content in studied species was Fe>Pb>Cr>Mn>Zn>Cu>Ni>Cd>Co. The concentration of heavy metals were distinctly lower than the threshold value as suggested by World Health Organization and Food Safety and Standards Authority of India, except for Cr and Pb in few species. THQ values were below the acceptable limit. However, the estimated mean HI values were >1 for children, indicating they may be vulnerable to health risk due to continuous consumption of contaminated aquatic species from the study area. In contrast, the cancer risk for Cr, Cd, and Pb was below the acceptable range. Principal component analysis (PCA) discerned nearby petrochemical industry, electroplating industry, pesticides and fertilizer from agricultural runoff, as the potential sources of metal bioaccumulation in different tissues. Although the study reveals that metal contamination in aquatic species does not pose any immediate human health effect, continuous monitoring of the study area is recommended, as some metals have demonstrated their ability to accumulate in the tissues.

Essential and toxic metal concentrations in biological samples of multiple sclerosis patients: A systematic review and meta-analysis.

The role of trace elements and toxic metals on human health has been extensively discussed concerning disease pathogenesis and risk factors of diseases. In this systematic review and meta-analysis, we aimed to investigate arsenic (As), cadmium (Cd), lead (Pb), iron (Fe), zinc (Zn), and magnesium (Mg) levels in individuals with multiple sclerosis (MS) and healthy controls. We searched different databases/search engines for this systematic review and meta-analysis, including Web of Science, PubMed, Scopus, and Google Scholar, until June 27, 2024. Out of 5466 studies identified, 65 met our eligibility criteria and were included in the systematic review. For the meta-analysis, 58 studies with 10420 participants (5316 multiple sclerosis patients and 5104 healthy controls) had adequate data for inclusion. Results from the pooled data, analyzed using a random-effects model, revealed higher levels of As (Hedge's g = 4.00 μg/l, 95% CI = 2.03 to 5.98, P <0.001; I2 = 97.69%, P<0.001) and Cd (Hedge's g = 1.20 μg/l, 95% CI = 0.13 to 2.27, P = 0.028; I2 = 97.99%, P<0.001) in multiple sclerosis patients compared to healthy ones. However, no significant differences were observed in the concentrations of Zn, Fe, Mg, and Pb between the two groups. This study identified elevated As and Cd levels in MS patients, indicating the need for targeted interventions and public health guidelines for toxic metal exposure. Limiting exposure to contaminated environments and maintaining essential element levels through natural resources or supplements is essential, as there may be a possible relationship between multiple sclerosis and the concentrations of these elements in humans.

Spatial Distribution, Source Apportionment, and Pollution Assessment of Toxic Metals Around Agricultural Soils Based on APCS-MLR Receptor Modelling: A Case Study of the Northern Slope of Tianshan Mountains

To investigate the contamination status and analyze the sources of soil toxic metal contamination on the northern slopes of the East Tianshan mountain industrial belt in Xinjiang, northwest China, this study measured the contents of six common toxic metals such as Zn, Cu, Cr, Pb, Hg and As in 82 surface soil (0–20 cm), and using the ground accumulation index, pollution load index, and improved weighted index assessed the contamination characteristics of the soil and using a semi-variance function and APCS-MLR model the identified the potential sources of contamination. The results indicate that the average concentrations of Pb, Hg, and As are significantly higher than the background values in Xinjiang. The average ranking of toxic metal content is as follows: Zn &gt; Cr &gt; Pb &gt; Cu &gt; Hg &gt; as. A single-factor pollution index analysis shows that As and Pb pollution are severe, while Hg and Cu pollution are moderate. The improved weighted index shows that moderate lead pollution accounts for 6.1% and severe lead pollution accounts for 54.88%; 98.88% of arsenic is severely contaminated. The APCS-MLR model identified three main sources of heavy metals: Cu and Cr as industrial production sources, Pb and Zn as transportation and agricultural activity sources, and As, Cr, Cu, Hg, and Zn as natural and mixed pollution sources. This study provides a solid scientific basis for the prevention and control of toxic metal pollution in agricultural soils, thus ensuring food security and sustainable development in the region.

Health risk assessment of lead and cadmium in milk-based products of Iran

The primary objective of this study is to assess the health risks associated with lead (Pb) and cadmium (Cd) contamination in dairy products consumed in Iran. To conduct the research, 132 samples of cow milk, yogurt, cream, and doogh (a traditional Iranian beverage) were collected from both traditional and industrial livestock farms in Zanjan, Iran. The samples were microwave-digested, and an atomic absorption spectrophotometer equipped with a graphite furnace was used to determine toxic metals contents. The findings of the study revealed that the average concentrations of Pb in milk and dairy product exceeded the permitted limits. The mean ± se levels of Pb and Cd in milk, yogurt, doogh, and cream were 92.64 ± 8.73, 52.19 ± 8.42, 78.80 ± 12.89, 106.07 ± 8.94 μg/kg and 2.34 ± 0.22, 1.21 ± 0.20, 2.59 ± 0.57, 5.61 ± 0.63 μg/kg, respectively. For the purpose of exposure assessment, the chronic daily intake (CDI) was utilized, while the Hazard Quotient (HQ) and Total Hazard Quotient (THQ) were employed for non-carcinogenic risk assessment. Additionally, the Incremental Lifetime Cancer Risk (ILCR) was utilized for carcinogenic risk assessment. The results revealed that the highest exposure to Pb and Cd in the P 95th of CDI were observed in milk, followed by yogurt, doogh, and cream. According to our finding, the HQ and THQ values for potentially toxic elements (PTEs) related to the consumption of dairy products in the P 95th of cumulative probability were below 1. The results indicate that the ILCR of Cd (P 95th) due to the consumption of dairy products falls within the acceptable risk range (10−4 to 10−6). While our findings indicate levels of Cd in dairy products, it is important to note that there are currently no established standards for permissible Cd concentrations in Iran. Therefore, further research and regulatory frameworks are needed to ensure public safety.

Assessment of some heavy metals concentration in turkey meat in Kurdistan province and their relationship with oxidative stress and human health indicators.

The accumulation of heavy metals is closely related to biochemical parameters and the overall health of both animals and humans. Given the high nutritional value of turkey meat, this study aimed to assess the concentrations of toxic and non-toxic heavy metals in the breast, thigh, and liver tissues of turkeys and examine their relationship with oxidative stress biomarkers. In this cross-sectional study, 150 samples of turkey breast, thigh, and liver from Kurdistan province were collected using a cluster random sampling method. The concentrations of toxic and non-toxic heavy metals were measured using ICP-MS. The correlation between oxidative stress parameters and metal concentrations was investigated. Additionally, the target hazard quotient (THQ) and total risk (TR) for toxic heavy metals were calculated as health indicators. The results indicated that toxic heavy metals, including arsenic, cadmium, and mercury, had significantly higher accumulation in the liver compared to other turkey tissues (P < 0.05). Non-toxic metals, except for magnesium, also demonstrated higher levels in the liver (P < 0.01). The lowest antioxidant enzyme activities of SOD and GPx were observed in the liver, while the highest activities were found in the breast. However, the MDA concentration in the liver (8.96 ± 1.67) was significantly higher than in other tissues (P = 0.016). There was a significant negative correlation between the concentrations of arsenic, cadmium, and mercury and the activities of SOD and GPx enzymes. Conversely, the correlation between MDA and non-toxic metals, including selenium, zinc, and magnesium, was negative (P < 0.05). The accumulation of metals such as arsenic, mercury, copper, and cobalt exceeded permissible levels. The THQ for toxic metals was acceptable; however, the TR for arsenic in the breast, thigh, and liver tissues was within the carcinogenic range. Therefore, reducing and controlling the sources of arsenic as a toxic metal with oxidative effects in turkeys in Kurdistan province requires stringent monitoring and management.

Toxic metal concentration and ecological risk assessment in surface water, soil sediment, and atmosphere in two selected creeks in Rivers State

Toxic metal concentration and ecological risk assessment in surface water, soil sediment, and atmosphere in two selected creeks in Rivers State

Metals in Wildfire Suppressants.

Frequent and severe wildfires have led to increased application of fire suppression products (long-term fire retardants, water enhancers, and Class A foams) in the American West. While fire suppressing products used on wildfires must be approved by the U.S. Forest Service, portions of their formulations are trade secrets. Increased metals content in soils and surface waters at the wildland-urban interface has been observed after wildfires but has primarily been attributed to ash deposition or anthropogenic impact from nearby urban areas. In this study, metal concentrations in several fire suppression products (some approved by the U.S. Forest Service, and some marketed for consumer use) were quantified to evaluate whether these products could contribute to increased metal concentrations observed in the environment postfire. Long-term fire retardants contained concentrations of toxic metals (V, Cr, Mn, Cu, As, Cd, Sb, Ba, Tl, and Pb) 4-2,880 times greater than drinking water regulatory limits, and potentially greater than some aquatic toxicity thresholds when released into the environment. Water enhancers and Class A foams contained some metals, but at lower concentrations than fire retardants. Based on these concentrations and retardant application records, we estimate fire retardant application in the U.S. contributed approximately 380,000 kg of toxic metals to the environment between 2009 and 2021.

Health risk assessment of toxic metals and DNA damage in somatic and germ cells by soil and groundwater of a major cement factory in Nigeria.

The waste generated from cement manufacturing is an important source of heavy metal contamination of groundwater and soil. This study investigated the concentration of toxic metals in the soil of a major cement factory and nearby groundwater. Ecological and carcinogenic risks of the metals were calculated. Potential reproductive toxicity and genotoxic effects of the samples were assessed in sex and somatic cells of male mice using sperm abnormalities and bone marrow micronucleus (MN) assays, respectively. Also, the serum ALP, ALT, AST, Total Testosterone (TT), Luteinizing Hormone (LH), and Follicle Stimulating Hormone (FSH); and liver SOD and CAT activities were measured in the treated mice. Cr, Cu, Ni, Zn, Mn, Cd, and Pb levels in the soil and groundwater exceeded the allowable maximum standard. Ingestion and dermal contact were the most probable routes of human exposure with children having about three times higher probability of exposure to the metals than the adults. Ni, Pb, and Cr presented carcinogenic risks in children and adults. In the MN result, nuclear abnormalities in the studied mice especially micronucleated polychromatic erythrocytes increased significantly (p < 0.05). Compared to the negative control, the ratio of PCE/NCE showed the cytotoxicity of the two samples. Data further showed a significant increase in the serum ALP, AST, and ALT while the liver CAT and SOD activities concomitantly decreased in the exposed mice. Sperm morphology result showed that the samples contained constituents capable of inducing reproductive toxicity in exposed organisms, with alterations to the concentrations of TT, LH, and FSH. Toxic metal constituents of the samples were believed to induce these reported reproductive toxicity and genotoxic effect. These results showed the environmental pollution caused by cement factory and the potential effects the pollutants might have on exposed eukaryotic organisms.

Potential of Selected Species of Spiraea L. for Phytoremediation of Heavy Metals from Soils of Urban Areas

Four taxa of Spiraea were selected for this study: S. × cinerea Zabel ‘Grefsheim’, S. nipponica Maxim. ‘Snowmound’, S. splendens É. N. Baumann ex K. Koch and S. × vanhouttei (Briot) Carrière growing for a minimum of 5 years along heavily trafficked traffic routes. This study included the genus Spiraea due to its popularity in horticultural practice (commercial availability, widespread in urban environments). In addition, the use of ornamental shrubs for phytoremediation in urban green spaces effectively combines the aesthetic needs of residents with those of caring for the urban environment. This study was conducted in Poznań (population 550,000, the fifth largest city in Poland). Soils and foliage were examined in spring and autumn. Soil pH and specific electrolytic conductivity (EC) were determined. The content of micronutrients (Cu, Fe, Mn, Ni, Zn) and toxic heavy metals (Cd, Cr, Pb) in soil dry matter and leaves was determined. The uptake capacity of bioavailable forms of heavy metals by Spiraea from the soil was analyzed by determining the bioconcentration factor (BCF). It was found that the studied taxa meet the basic requirements for plants used for soil phytoremediation processes, especially for chromium phytoextraction. The degree of salinity of the tested soils did not pose a threat to the shrubs growing there, and most of the sites, despite the alkaline reaction, are suitable for their cultivation. S. × cinerea and S. × vanhouttei have BCFs for lead &lt;1. The remaining taxa are characterized by strong concentrations of all analyzed elements. A particularly high BCF, above 10, was recorded for chromium and high for manganese and nickel.

Comprehensive analysis of nutritive and toxic metal contents in canned tuna: Implications for safety and consumer health

Ca, Mg, K, Na, Fe, Cu, Mn, Zn, Ni, Cr, As, Cd, Pb and Hg levels of canned tuna fish marketed in Turkey were determined by inductively coupled plasma mass spectrometry. Ca content ranged from 80 to 2930 mg/kg, Mg from 900 to 1910 mg/kg, Na from 5930 to 12130 mg/kg, and K from 6930 to 44340 mg/kg. Fe (4.73–27.34 mg/kg), Cu (0.21 and 0.98 mg/kg), Mn (0.12–0.44 mg/kg), Zn (32–45 mg/kg), Ni (0.88–2.06 mg/kg) and Cr (0.03–0.11 mg/kg) contents of the canned foods did not exceed the provisional tolerable weekly intake limit. Cd was detected in two groups (C4=0.02 mg/kg, C18=0.15 mg/kg), while Pb was found in one group (C10=0.48 mg/kg). As content ranged from 0.27 to 1.75 mg/kg in all groups. Most of the tuna cans contained Hg between 0.046 and 0.099 mg/kg, but the highest concentration was found in sample C4 (0.81 mg/kg). Based on the increased lifetime cancer risk findings, the consumption limits of Group 4 and Group 14 should be limited to around 60 g/week (less for children). As a result of the findings that were obtained from this study careful observations should be followed up for the safer consumption of canned tuna.

Metal contamination in mangrove tissues, seeds, and associated sediments from the Vattanam mangrove forest of Palk Bay, southeastern India: An ecological risk assessment

In the present work, the concentrations of toxic heavy metals in mangrove sediments, mangrove leaves, and seeds collected from five stations in the Vattanam mangrove of Palk Bay, southeastern India, as well as the effects of the monsoon season on toxic heavy metals concentrations were determined. The concentrations were 17.5 μg/g for zinc (Zn), 9.11 μg/g for copper (Cu), and 6.03 μg/g for lead (Pb) in sediments; 10.71 μg/g (Zn) and 8.94 μg/g (Cu) in mangrove leaves; and 26.24 μg/g (Zn) and 17.01 μg/g (Cu) in mangrove seeds. At all sampling stations, the Cd concentration was below the limit of detection. These mangroves seem to have adapted successfully to their environment given their selective intake of only essential metals (Cu and Zn) and the restricted movement of non-essential metals (Cd and Pb). The concentrations of metals were below the maximum residual limits regulated by national and international standard limits.

Photosystems functioning, the content of chemical elements, flavonoids and brassinosteroids in leaves of chimera Cornus controversa

he formation of chimera is a well-known phenomenon in variegated ornamental and wild plants, but the biochemical peculiarities of this phenomenon are not well studied. The purpose of this work was to conduct a comparative study of the photosynthetic apparatus functioning, the content of macro-, microelements, flavonoids and brassinosteroids in the variegated and green leaves of the periclinal chimera Cornus controversa plant grown in the collection of M. M. Gryshko National Botanical Garden of the NAS of Ukraine. Sampling was made during the period from June to October 2022. The content of photosynthetic pigments and brassinosteroids was measured spectrophotometrically, autofluorescence of leaf tissues was studied using an inverted microscope with a multi-channel fluorescence imaging system, Normalized difference vegetation index (NDVI) – using GreenSeeker devices and fluorimeter, the level of macro- and microelements – using plasma emission spectrometer. Phenolic secondary metabolites were separated by HPTLC. To assess the protective capacity of flavonoids, a bioassay on the germination of radish seeds Raphanus in the presence of AlCl3 was used. It was shown that green leaves of C. controversa chimera, compared to variegated ones, had a twice as high NDVI index, maintained photosynthetic function longer in autumn, and had higher content of macronutrients (Mg, Ca and S) but lower concentration of toxic metals (Al, Cu, Fe, Zn, Ti). Instead, variegated leaves accumulated more brassinosteroids and phenolic metabolites, which were found not only to reduce the toxic effect of aluminum but also to have a growth-stimulating effect on the roots of radish seedlings. Such specialization of green and variegated leaves may contribute to better plant chimeras adaptation to environmental pollution. Keywords: brassinosteroids, Cornus controversa, macroelements, microelements, NDVI index, periclinal chimera, phenolic metabolites, photosynthetic pigments, tissue autofluorescence

Metal tolerance of Río Tinto fungi.

Southwest Spain's Río Tinto is a stressful acidic microbial habitat with a noticeably high concentration of toxic heavy metals. Nevertheless, it has an unexpected degree of eukaryotic diversity in its basin, with a high diversity of fungal saprotrophs. Although some studies on the eukaryotic diversity in Rio Tinto have been published, none of them used molecular methodologies to describe the fungal diversity and taxonomic affiliations that emerge along the river in different seasons. The aim of the present study was to isolate and describe the seasonal diversity of the fungal community in the Río Tinto basin and its correlation with the physicochemical parameters existing along the river's course. The taxonomic affiliation of 359 fungal isolates, based on the complete internal transcribed spacer DNA sequences, revealed a high degree of diversity, identifying species belonging primarily to the phylum Ascomycota, but representatives of the Basidiomycota and Mucoromycota phyla were also present. In total, 40 representative isolates along the river were evaluated for their tolerance to toxic heavy metals. Some of the isolates were able to grow in the presence of 1000 mM of Cu2+, 750 mM of As5+ and Cd2+, and 100 mM of Co2+, Ni2+, and Pb2+.

Human Exposure through the Diet to Arsenic and Other Toxic Elements: A Literature Review of Scientific Studies Conducted in Catalonia, Spain, in the Current Century.

Human exposure to arsenic and other toxic elements such as cadmium, lead and mercury may lead to a wide range of adverse health effects. In relation to this, it is well established that the diet is the main route of exposure to both essential and toxic trace elements. In recent years, the levels of toxic elements in foodstuffs have been measured in numerous studies conducted all over the world. Scientific databases show that, in the current century, China and Spain have been the countries where the most surveys on this topic have been carried out. Regarding Spain, Catalonia is the region where most studies aimed at determining the concentrations of trace elements in food have been performed. The objective of this paper was to review the studies carried out in Catalonia on the concentrations of As and toxic metals (including Cd, Hg and Pb) in food, as well as their estimated dietary intakes (EDIs). The results of total diet studies (TDSs) and duplicate diet (DD) studies have been included. For most toxic elements, a continued reduction in the EDI has been observed. This reduction is associated with a decrease in their concentrations in food, and with certain changes in dietary habits. Fish and seafood is the food group showing the highest content of toxic elements. However, none of the adult groups exceeded-in general-the safety thresholds for As, Cd, Hg and Pb established by the European Food Safety Agency (EFSA).