Elevated Metal Concentrations Research Articles

P1273 High Crohn's Disease incidence associated with multiple heavy metal contamination in agricultural soils: findings from the CROPS project in Northern France

Abstract Background Crohn's Disease (CD) is a chronic intestinal disease with an unclear etiology and suspected environmental risk factors. The CROPS (CROhn’s disease and Pollution of Soils) project was initiated in Northern France to investigate links between the high incidence of CD and environmental pollutants. In this context, we combined data of a population-based registry of Inflammatory Bowel Disease (IBD) with environmental sampling data to identify the environmental profile of multi-contamination associated with high incidence. Methods This ecological study was conducted at the municipal level within the coverage area of the registry in Northern France. All patients diagnosed between 2000 and 2017 were included (n=9,019). Spatial clusters of significantly high (n=4) and low (n=4) CD incidence, adjusted for age and sex, were identified based on patients' residence addresses at diagnosis. Within these clusters, environmental sampling was performed across 240 sites using a hexagonal grid to ensure 30 samples per cluster. A total of 490 parameters were analyzed: 306 in soil (including emerging pollutants such as hormones and antibiotics, polycyclic aromatic hydrocarbons [PAHs], heavy metals, and pesticides), 152 in tap water (examining heavy metals and PAHs), and 30 in lichens (assessing heavy metals as indicators of air quality). Multi-contamination indices, such as the Mean Impregnation Ratio (MIR) and Pollution Index, were applied. Data analysis included Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Analysis of Variance (ANOVA) tests. Results High-incidence clusters, predominantly agricultural, had elevated heavy metal concentrations in soil (notably chromium, arsenic, zinc, and nickel), sulfadiazine in soils, high nitrate levels in water, and heavy metals in lichens. Low-incidence clusters, with greater urbanization, showed elevated PAHs in soil, heavy metals in water, and BPA in soils. Pollution profiles aligned with different land covers, with significant findings for agricultural lands (p<0.0001). A positive correlation between the relative risk and soil’s MIR for heavy metals in agricultural zones was noted (r=0.557, p=0.005). Conclusion These findings suggest a possible link between high CD incidence and heavy metal exposure in agricultural lands. Profiles of pollution were created for each cluster. Future studies should expand on pesticide and agricultural pollutant analysis to strengthen this hypothesis, and consider individual-level epidemiological approaches to further elucidate these potential environmental risk factors.

A systematic review on concentration of residential indoor air metals and health risk assessment

This review evaluates metal concentrations in indoor air within residential buildings, focusing on original research published in English from 2010 to 2022. We conducted a comprehensive literature search across Google Scholar, ScienceDirect, and SpringerLink, identifying 34 relevant studies measuring metal concentrations in various residential environments. Data extraction revealed significant regional variations, with urban homes exhibiting higher metal concentrations compared to rural and industrial areas. Chromium (Cr) levels in urban regions reached 116.00±170.00 mg/kg, compared to 63.40±34.80 mg/kg in rural areas and 30.90±16.90 mg/kg in industrial regions. Nickel (Ni) concentrations were also higher in urban homes at 86.10±126.00 mg/kg, versus 27.60±9.08 mg/kg in rural and 20.40±7.65 mg/kg in industrial settings. The living room showed the highest metal concentrations, with lead (Pb) at 170.00±NA mg/kg and nickel (Ni) at 174.00±144.00 mg/ kg, significantly higher than in bedrooms and kitchens (p<0.05). Seasonal variations indicated elevated warm season metal concentrations, with iron (Fe) measured at 11,200 ± 9830 mg/kg. Health risk assessments highlighted a total cancer risk (CR) of 1.59 × 10⁻³ in industrial areas, exceeding acceptable limits (10⁻5 to 10⁻⁶). The ingestion pathway was the primary route for both cancer and non-cancer risks, with copper (Cu) posing the highest potential cancer risk across all regions. These findings emphasize the need for monitoring and regulation of indoor metal concentrations, particularly in industrial areas.

Characterization and Environmental Impact of Produced Water from Oil Fields in the Sirte Basin, Libya

This study evaluates the characteristics and environmental implications of produced water discharged from Zaltan, Al-Lahib, and Al-Jabal oil fields in the Sirte Basin, Libya. The fields collectively produce 217,800 barrels of untreated produced water daily, containing exceptionally high levels of total dissolved solids (TDS) ranging from 40,000 ppm (Zaltan) to 160,000 ppm (Al-Lahib). Elevated concentrations of heavy metals, including mercury (100 mg/L), iron (105 mg/L), and lead (65 mg/L) in Al-Lahib, far exceed safe environmental limits. Inorganic ions such as chloride (26,658 mg/L), nitrate (10,034 mg/L), and bicarbonate (12,806 mg/L) contribute to significant salinization and groundwater contamination risks. These findings highlight the severe environmental impact of produced water discharge, including soil degradation, ecosystem disruption, and threats to public health. Implementing advanced treatment technologies, such as reverse osmosis, electrocoagulation, and constructed wetlands, is recommended to mitigate these risks and ensure sustainable water management.

Phragmites australis elevated concentrations of soil-bound heavy metals and magnetic particles in a typical urban plateau lake wetland, China.

Vegetation change significantly altered the hydrological processes and soil erosion within riparian ecosystems. It is unclear how change in managed vegetation types affect the geochemical behavior of heavy metals (HMs) and magnetic particles in karst riparian areas. Two soil depths of 0-20cm and 20-40cm were taken in alien species Phragmites australis (P. australis), native species Juncus effuses and Schoenoplectus tabernaemontan in a typical urban plateau Lake wetland, Caohai lake, China. Low-frequency mass magnetic susceptibility (χLF), anhysteretic remanent susceptibility (χARM), isothermal remanent magnetization, Cd, Cr, Cu, Sb, Ni and Zn were determined. Compared with Juncus effuses and Schoenoplectus tabernaemontani, P. australis habitat had the higher values of HMs, χLF, χARM, and isothermal remanent magnetization in top-soils. Frequency-dependent magnetic susceptibility ranged from 4.84% to 10.87% in top-soils and 6.82%-9.95% in sub-soils, lithogenic/pedogenic factors mainly masked the contribution of anthropogenic factors to magnetic signal enhancement. The correlation between variations of Cu and Sb with χARM and isothermal remanent magnetization was found to be significant in top-soils, but not in sub-soils. P. australis tended to promote the enrichment of HMs and enhancement of magnetic signal, the impact of P. australis expansion on the distribution of soil HMs and magnetic particles in Caohai riparian wetland should be not disregarded.

Vitamin E Intake Attenuated the Association Between Elevated Blood Heavy Metal (Pb, Cd, and Hg) Concentrations and Diabetes Risk in Adults Aged 18-65 Years: Findings from 2007-2018 NHANES.

The association between heavy metal exposure and diabetes is controversial and vitamin E (VE) may reduce diabetes risk. We aimed to examine the associations between blood heavy metals (BHMs) and diabetes risk and VE's role in the relationship. From the 2007-2018 NHANES, 10,721 participants aged ≥ 18 were included for multiple statistical analyses, which revealed that BHMs and dietary VE intake were negatively associated with diabetes and fasting plasma glucose (FPG). The diabetes prevalence in each quartile (Q) of heavy metal exposure increased with age, but within age Q4, it generally decreased with exposure quartiles. Moreover, BHMs were positively associated with all-cause and diabetes-related mortalities with aging, which induced an age breakpoint of 65 years for age-stratified analyses on the associations between BHMs and diabetes risk. In those aged > 65, BHMs were negatively correlated with diabetes risk and its biomarkers; however, in adults aged 18-65, the correlation was positive. At higher VE intake levels, blood lead was associated with a lower diabetes risk and all three BHMs demonstrated lower FPG levels than those at lower VE intake levels. In conclusion, consuming sufficient VE and avoiding heavy metal exposure are highly recommended to reduce diabetes risk.

Intersection of Wildfire and Legacy Mining Poses Risks to Water Quality.

Mining and wildfires are both landscape disturbances that pose elevated and substantial hazards to water supplies and ecosystems due to increased erosion and transport of sediment, metals, and debris to downstream waters. The risk to water supplies may be amplified when these disturbances occur in the same watershed. This work describes mechanisms by which the intersection of mining and wildfire may lead to elevated metal concentrations in downstream waters: (1) conveyance of metal-rich ash and soil to surface waters, (2) increased dissolution and transport of dissolved metals due to direct contact of precipitation with mine waste, (3) increased erosion and transport of metal-rich sediment from mining waste, (4) remobilization of previously deposited metal-contaminated floodplain sediment by higher postfire flood flows, and (5) increased metal transport from underground mine workings. Predicted increases in wildfire size, frequency, and burn severity, together with the ongoing need for metal resources, indicate that improved mapping, monitoring, modeling, and mitigation techniques are needed to manage the geochemical hazard of the intersection of wildfire and mining and implications for water availability.

Potentially harmful elements in mining sites in Ghana: assessment of their carcinogenic and non-carcinogenic health risks for children and adults

PurposePotentially harmful elements (PHEs) in the soil at gold mining sites can endanger the health and sustainability of the local community. We examined the potential health risks associated with the presence of PHEs (Al, Cd, Cu, Fe, Hg, Mn, Pb, Sb, Se and Ti) in the soils of active, closed/abandoned/former and profile gold mine sites in Ghana.Design/methodology/approachWe collected 102 soil samples from these mine sites, analysed them for their total element contents and calculated the geo-accumulation index, enrichment factor, contamination factor and pollution load index (PLI) (Igeo). We calculated the risks to human health by utilizing the hazard index (HI) and hazard quotient (HQ) for adult males, adult females and children who may ingest contaminated soil particles.FindingsThe average total Cd concentration in the soils was above the global average of 0.2 mg/kg for abandoned (2.86 mg/kg), active (3.93 mg/kg) and profile (4.04 mg/kg) areas. Mercury was detected at elevated concentrations in the soil of active mines (0.92 mg/kg), profiles (0.89 mg/kg) and abandoned mines (0.87 mg/kg). In the active, abandoned and profile soils, titanium concentrations were 14.18, 6.74 and 4.82 mg/kg, respectively, in several folds above the global average of 0.57 mg/kg. The majority of the sites were contaminated with Cd, Hg and Ti based on the calculated PLI values (active = 2.04, abandoned = 1.77 and profile = 2.7). Cadmium, mercury, lead and titanium in mine spoils were found to be correlated with aluminium, iron, manganese, pH, total carbon, clay content and phosphorus in a multivariate analysis using correlation and principal component analysis.Research limitations/implicationsBoth natural and anthropogenic processes contributed to the elevated metal contents in the mining sites, as indicated by the investigation’s results. The children’s hazard index values exceeded the threshold of 1.0, indicating the presence of non-carcinogenic risks.Practical implicationsGreen space technology (e.g. revegetation) may thus be critical for preserving public health and reviving the ecological integrity of the contaminated sites.Originality/valueThis study highlights health risks to local communities in southwest Ghana by investigating the presence of potentially harmful elements in soils from gold mining sites for the first time. It assesses non-carcinogenic and carcinogenic health risks using a methodology recommended by the US Environmental Protection Agency for soil-to-human health risk assessment, especially for children. The study highlights how contamination has been found, making green space technology essential for preserving ecological integrity and protecting public health. The inclusion of geospatial distribution mapping of PTEs offers a visual depiction of the spread of contamination at both active and closed mining sites.

Role of Polyphosphate as an Inorganic Chaperone to Prevent Protein Aggregation Under Copper Stress in Saccharolobus solfataricus.

Polyphosphates are biopolymers composed of phosphate monomers linked by high-energy phosphoanhydride bonds. They are present across all life domains, serving as a source of energy, metal chelators, and playing a crucial role in stress defense. In Escherichia coli, polyphosphates also function as inorganic molecular chaperones. The present study aims to investigate whether polyphosphate serves a similar chaperone function in archaea, using Saccharolobus solfataricus as a model organism. To this end, polyphosphate was extracted and quantified, the ADP/ATP ratio was determined, insoluble protein extracts were analyzed at different time points after copper exposure, and qPCR was performed to measure the expression of stress-related genes. PolyP was extracted after exposing the archaeon S. solfataricus to different copper concentrations. We determined that polyP degradation is directly correlated with metal concentration. At the minimum inhibitory concentration (MIC) of 2 mM Cu2+, polyP degradation stabilized 2 h after exposure and showed no recovery even after 24 h. The ADP/ATP ratio was measured and showed differences in the presence or absence of polyP. The analysis of proteins precipitated under copper stress showed a higher proportion of insoluble proteins at an elevated metal concentration. On the other hand, increased protein precipitation was detected in the absence of polyP. Gene expression analysis via qPCR was conducted to assess the expression of genes involved in chaperone and chaperonin production, copper resistance, oxidative stress response, and phosphate metabolism under prolonged copper exposure, both in the presence and absence of polyP. The results indicated an upregulation of all the chaperonins measured in the presence of polyP. Interestingly, just some of these genes were upregulated in polyP's absence. Despite copper stress, there was no upregulation of superoxide dismutase in our conditions. These results highlight the role of polyP in the copper stress response in S. solfataricus, particularly to prevent protein precipitation, likely due to its function as an inorganic chaperone. Additionally, the observed protein precipitation could be attributable to interactions between copper and some amino acids on the protein structures rather than oxidative stress induced by copper exposure, as previously described in E. coli. Our present findings provide new insights into the protective role of polyP as an inorganic chaperone in S. solfataricus and emphasize its importance in maintaining cellular homeostasis under metal stress conditions.

Using mercury and lead stable isotopes to assess mercury, lead, and trace metal source contributions to Great Salt Lake, Utah, USA

Great Salt Lake is a critical habitat for migratory birds that is threatened by elevated metal concentrations, including mercury (Hg) and lead (Pb), and is subject to severe hydrologic changes, such as declining lake level. When assessing metal profiles recorded in Great Salt Lake sediment, a large data gap exists regarding the sources of metals within the system, which is complicated by various source inputs to the lake and complex biogeochemistry. Here, we leverage Hg and Pb stable isotopes to track relative changes in metal source contributions to Great Salt Lake over time. Mercury and Pb concentrations increase in sediments deposited after 1920 and peak between 1965 and 1995, following closure of several local smelters and the onset of increased emission controls. The nominal associations above are confirmed via Hg stable isotopes in pre-1920 background sediments, which reflect atmospheric inputs from regional and global origin, whereas Hg and Pb stable isotopes together indicate that elevated metal concentrations in mid-late 20th century sediments reflect increased mining/smelting inputs. The observed minimal rebound towards pre-1920 Pb isotope signatures in 21st century sediments indicates that mining/smelting inputs, though reduced, remain a primary source of Pb to Great Salt Lake. In contrast, the more pronounced rebound of Hg stable isotope signatures to pre-1920 values indicate a greater contribution of atmospheric inputs of regional/global origin to current Hg inputs, though Hg concentrations are ~10 times greater than pre-1920 background values due to global increases in atmospheric Hg concentrations or possibly slow recovery from local contamination. The importance of regional/global Hg sources to the system suggests that reductions in Hg bioaccumulation in the open water food webs of Great Salt Lake are more dependent on national and global reductions in Hg emissions and management strategies to limit methylmercury production within system. This work highlights the utility of using coupled Hg and Pb stable isotope values to assess trace metal pollution sources and pathways in aquatic systems.

Investigating MerR's Selectivity: The Crosstalk Between Cadmium and Copper Under Elevated Stress Conditions.

Bacteria respond to metal pollution through sensors that control the uptake and the detoxification machineries. Specificity in metal recognition is therefore a prerequisite for triggering the appropriate response, particularly when facing a mixture of metals. In response to Cu+, the purple bacterium Rubrivivax gelatinosus induces the efflux Cu+-ATPase CopA by the Cu+ regulator CopR. However, genetic analyses have suggested the presence of additional regulators. Here, we show that CadR, the Cd2+ sensor, is involved in Cd2+ and Cu+ tolerance and demonstrate that CopR and CadR share common target genes. Interestingly, expression of the Cu+ detoxification and efflux (CopI/CopA) system was induced by Cd2+ and downregulated in the double mutant copRcadR-. This double mutant was more sensitive to low Cu+ concentration than the single copR- mutant, and accumulation of coproporphyrin III pointed to a significantly decreased expression of CopA. Furthermore, analyses of Cd2+ toxicity in the cadR- mutant suggested that although CopR is Cu+ selective, CopR is involved in Cd2+ response since the addition of Cu+ alleviates Cd2+ toxicity. Based on our current knowledge of metal transport across the inner membrane, Cd2+ and Cu+ do not share common efflux routes nor do they share common regulators. Nevertheless, the crosstalk between Cd2+ and Cu+ tolerance systems is demonstrated in the present study. The modulation of Cu+ detoxification by a Cd2+ regulator in vivo places emphasis on the relaxed selectivity, under elevated metal concentration, in MerR regulators.

Microbial communities of urban and industrial polluted soils in the Russian Arctic

The Russian Arctic presents a unique environment for studying the effects of anthropogenic pressure on soil microbial communities under severe climatic conditions. This study investigated the impact of chemical pollution on soil microbial properties by comparing urban and industrially polluted soils in Murmansk region with natural Podzols. Urban soils exhibited significant alterations, including shifts in pH and increased carbon and nutrient contents compared to natural soils. Industrially polluted soils near the copper‑nickel smelter were characterized by elevated heavy metal concentration, while those near the aluminum smelter showed high fluorine and aluminum content. In both cases, carbon content and pH remained similar to natural soils. Industrial emissions significantly changed the soil microbiome, with effects varying depending on the pollution source and chemical composition of the emissions. Soils near the copper‑nickel smelter showed a decline in bacterial gene copies and actinomycete mycelium length, with a predominance of Chloroflexii and Ascomycota. Conversely, soils near the aluminum smelter exhibited less pronounced changes, with Proteobacteria and Basidiomycota being prevalent. Despite these differences, both industrially impacted sites displayed reduced microbial diversity, regardless of the composition of the emissions. In contrast, urban soils demonstrated increased microbial diversity, likely attributed to the emergence of new, favorable ecological niches. Microbial communities in both cities were similar, dominated by Proteobacteria and Ascomycota, and displayed an increase in bacterial gene copies compared to natural soils. These findings highlight the contrasting influences of urban and industrial development on soil microbial communities. While industrial activities suppress microbial life, urbanization fosters the creation of new niches, promoting microbial diversity. This underscores the potential of urban soils to support diverse microbial communities, which is crucial for sustainable development and ecological strategies in Arctic cities.

Human exposure to heavy metals and possible public health risks via consumption of mussels M. galloprovincialis from the Albanian sea cost

Heavy metals in the marine environment are significant contaminants that readily bioaccumulate in the tissues of aquatic organisms, particularly in filter-feeding animals such as bivalve molluscs. Human exposure to elevated concentrations of heavy metals, including essential elements such as Fe, Cu, and Zn, through the consumption of seafood can lead to various pathological effects. Research has demonstrated that among bivalve molluscs, mussels are the most effective indicators for monitoring marine pollution. Consequently, this study focused on the species Mytilus galloprovincialis to evaluate the levels of Al, As, Cd, Cr, Cu, Fe, Mg, Ni, Pb, and Zn in the two primary harvesting areas of Albania and to assess the associated human health risks from mussel consumption. The results revealed a concerning situation, particularly for Pb and Cd, with average concentrations of 2.15 μg/g and 4.14 μg/g, respectively, significantly exceeding the limits established by Regulation (EC) No. 915/2023. The levels of the other investigated elements also raised concerns, as only half of them were within the dietary intake values recommended by scientific authorities for weekly consumption of 250 g of mussels.

Optimizing in-situ upgrading of heavy crude oil via catalytic aquathermolysis using a novel graphene oxide-copper zinc ferrite nanocomposite as a catalyst

Unconventional resources, such as heavy oil, are increasingly being explored and exploited due to the declining availability of conventional petroleum resources. Heavy crude oil poses challenges in production, transportation, and refining, due to its high viscosity, low API gravity, and elevated sulfur and metal content. Improving the quality of heavy oil can be achieved through the application of steam injection, which lowers the oil’s viscosity and enhances its flow. However, steam injection alone falls short of meeting the growing demand for higher-quality petroleum products. Catalytic upgrading is therefore being investigated as a viable solution to improve heavy oil quality. This study experimentally investigates the application of two novel catalysts, namely copper-substituted zinc ferrite (ZCFO) synthesized via the sol–gel combustion method and a graphene oxide-based nanocomposite (GO-ZCFO) with different ratios, for catalyzing aquathermolysis reactions in the steam injection process, with the aim of enhancing the in-situ upgrading of heavy oil. These catalysts underwent characterization using X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscopy (TEM). Their catalytic performance was assessed utilizing a high-pressure/high-temperature reactor (300 ml), with a comprehensive analysis of the changes in the physical and chemical properties of the heavy oil before and after upgrading. This analysis included measurements of sulfur content, SARA fractions, viscosity, API gravity, and Gas Chromatography (GC) of saturated hydrocarbons and evolved gases. All upgrading experiments, including both catalytic and non-catalytic aquathermolysis processes, were conducted under a reaction time of 6 h, a reaction temperature of 320 °C, and high pressure (86–112 bar). The results indicated that the introduction of the proposed catalysts as additives into the upgrading system resulted in a significant reduction in sulfur content. This, in turn, led to a decrease in resin and asphaltene content, an increase in the content of saturated hydrocarbon, particularly low-molecular-weight alkanes, and ultimately, a reduction in viscosity along with higher API gravity of the crude oil. GO-ZCFO with a weight ratio (50:50) exhibited the best catalytic performance. The heavy crude oil, upgraded with this 50:50 ratio, exhibited significant enhancements, including a 29.26% reduction in sulfur content, a 21.27% decrease in resin content, a 37.60% decrease in asphaltene content, a 46.92% increase in saturated hydrocarbon content, a 66.48% reduction in viscosity, and a 25.49% increase in API gravity. In comparison, the oil upgraded through non-catalytic aquathermolysis showed only marginal improvements, with slight reductions in sulfur content by 5.41%, resin content by 3.60%, asphaltene content by 11.36%, viscosity by 17.89%, and inconsiderable increases in saturated hydrocarbon content by 9.9% and API gravity by 3.02%. The GO-ZCFO, with its high catalytic activity, stands as a promising catalyst that contributes to improving the in-situ upgrading and thermal conversion of heavy crude oil.

Simple fuzzy classification of metal qualities of Ona River, Ibadan, Nigeria, and its implication for fish production and other uses

Elevated concentrations of metals in rivers can pose significant risks to human health. Consequently, it is essential to monitor metal levels in river water to minimize human exposure, particularly through consumption of harvested fish and other uses. This study examined the water quality of the Ona River in Ibadan, Nigeria. Seven potentially toxic elements (PTEs), namely Fe, Cu, Mn, Zn, Pb, Cd, Cr and four macronutrients: Mg, Na, K, Ca were investigated. Surface and pore water samples were collected from six sampling points during the peak of the dry and the rainy seasons. These were analyzed according to standard procedures and processed using the Simple Fuzzy Classification (SFC) model with four classes. The results revealed that the PTEs: Fe, Pb, Cd, Cr, and Mn were detected above guideline limits in several sampling points, indicating possible contamination from anthropogenic sources. Simple fuzzy classification puts the quality of water in the investigated portion of the river in the range of 67.4–88.5% in the C1 (pristine) category during the dry season and 61.9–88.6% in C1 (pristine) during rainy season. However, there were membership functions of up to 58.7 and 63.2; 61.2 and 75.4 as well as 44.3 and 43.5% in C2, C3, and C4 categories (contaminated, polluted and extremely polluted, respectively) during the first and second sampling, respectively. Due to the high concentrations of toxic and bioaccumulative metals in the river, efforts should be made to control the discharge of pollutants into the river. These will prevent human health exposure risks tendencies for various uses, including fish production.

Pyrite trace metal and sulfur isotopic compositions track metalliferous fluid circulation within the Ordovician/Silurian organic-rich black shales in the eastern Sichuan Basin, southwestern China

Depicting metalliferous fluid flows in sedimentary basins has a remarkable implication for understanding the formation and evolution of organic-rich sediments. The Middle-Upper Yangtze region in South China hosts voluminous gaseous hydrocarbons and MVT-type ZnPb deposits. Natural gases are mainly distributed in the Sichuan Basin, yet ZnPb deposits are found in surrounding regions of the basin. Such a unique distribution pattern implies that the interplay between metalliferous fluids and organic-rich sediments may be extensive in the boundary of these two types of deposits. A typical Ordovician/Silurian (Wufeng/Longmaxi formations) organic-rich black shale outcrop occurs in the eastern boundary of the Sichuan Basin. Pyrites are frequently distributed across this section, providing an ideal opportunity to investigate features of metalliferous fluids and their potential impacts on organic-rich sediments. Pyrites associated with high-angle carbonate veinlets are recognized in the studied area, and this group of pyrites (“Group 2”) commonly display planar-laminated morphologies, moderate δ34S values (0.78 ‰–8.86 ‰), and elevated trace metal contents (Ni, Pb, Mn, Mo, Tl, and REE) than those not associated with carbonate veinlets. These features suggest that this group of pyrites may be precipitated via local metalliferous fluid flows. Besides, pyrites with relatively lower trace metal contents can be further divided into two groups, including a group of euhedral/subhedral pyrites with more depleted δ34S values (−18.06 ‰ – -1.15 ‰; “Group 1”) and a group of planar-laminated/cubic pyrites with enriched δ34S values (10.55 ‰–37.62 ‰; “Group 3”). Pyrites of Group 1 and Group 3 may be formed via bacterial sulfate reduction (BSR) and thermochemical sulfate reduction (TSR), respectively. The discovery of fluid-related, trace-metal-enriched pyrites implies that fluid circulation within organic-rich black shales has the potential to remobilize, transport, and re-deposit trace metals. Besides, metalliferous fluid may also promote organic matter maturation within the Sichuan Basin. The outcomes of this study, combined with previous findings of metalliferous fluid flows in the center of the basin and ZnPb mineralization belts surrounding the basin, imply that a widespread Ediacaran-Palaeozoic fluid circulation system may exist in the Middle-Upper Yangtze region.

Investigating the Spatial Patterns of Heavy Metals in Topsoil and Asthma in the Western Salt Lake Valley, Utah

Mining activities, particularly in large excavations like the Bingham Canyon Copper Mine in Utah, have been increasingly linked to respiratory conditions due to heavy-metal-enriched waste and dust. Operating continuously since 1906, the Bingham Canyon Copper Mine contributes 4.4% of the Salt Lake Valley PM2.5 pollution. However, the extent of its contributions to larger-sized particulate matter (PM10) dust, soil and water contamination, and human health impacts is largely unknown. Aerosol optical depth data from Sentinel-2 imagery revealed discernible dust clouds downwind of the mine and smelter on non-prevailing-wind days, suggesting potential heavy metal dispersion from this fugitive dust and subsequent deposition to nearby surface soils. Our analysis of topsoils from across the western Salt Lake Valley found mean arsenic, copper, lead, and zinc concentrations to be well above global background concentrations. Also, the minimum values for arsenic and maximum values for lead were well above the US EPA regional screening levels for residential soils. Thus, arsenic is the metal of greatest concern for impacts on human health. Elevated concentrations of all metals were most notable near the mine, smelter, and tailings pond. Our study linked these elevated heavy metal levels to regional asthma outcomes through cluster analysis and distance-related comparison tests. Significant clusters of high asthma rates were observed in regions with elevated topsoil heavy metal concentrations, impacting both low- and high-income neighborhoods. The findings of this preliminary study suggest that the mine, smelter, and recent construction activities, especially on lands reclaimed from former tailings ponds, could be contributing to atmospheric dust containing high levels of heavy metals and exacerbating asthma outcomes for residents. However, the methods used in the study with aggregated health outcome data cannot determine causal links between the heavy metal contents of soil and health outcomes; they can only point to potential links and a need for further investigation. Such further investigation should involve individual-level data and control for potential confounding factors, such as socioeconomic status, access to healthcare, and lifestyle factors, to isolate the effect of metal exposures on asthma outcomes. This study focused on atmospheric deposition as a source of heavy metal enrichment of topsoil. However, future research is also essential to assess levels of heavy metals in subsoil parent materials and local surface and groundwaters to be able to assess the links between the sources or methods of soil contamination and health outcomes.

Evaluation of human and ecological health risks associated with the potentially toxic heavy metals in groundwater of Vellore city, Tamil Nadu, India

Groundwater pollution by heavy metals is a significant and alarming threat globally, through its chronic effect on human health and ecosystem. The current study evaluated the identification and risk assessment of heavy metals in groundwater of the Vellore city, Tamilnadu, India. Groundwater samples were collected from 32 locations over a continuous period of 2022–2023 for every three months on seasonal basis. The samples were analysed for pH, Total Dissolved Solids (TDS), Hardness and heavy metals (Al, As, Ba, Cd, Cu, Pb, Al and Zn). The analysed mean concentrations of these heavy metals were found in the order: As > Cd > Pb > Ba >Zn >Al> Cu. Elevated concentrations of heavy metals were observed in 2022, likely influenced by rainfall and land use patterns. Heavy metals such as Al, As, Pb, and Cd exceeded the BIS limits and whereas Ba, Cu, and Zn concentrations remain within desirable limits. Groundwater Quality Index (GWQI) classified 41% as 'unfit for drinking'. Ecological risk indices (ERI) indicate significant contamination in 34% of samples, with Al and Pb being primary contributors. Non-carcinogenic health risk assessments reveal, chronic hazards, where children facing higher risks followed by men and women groups. Carcinogenic risk assessments indices such as Heavy metal pollution Index (HPI) shown 25% of samples in critical quality, Heavy metal Evaluation Index (HEI) evaluated all samples were in low contamination and Contamination Index (CI) shown 72% samples under high contamination posing high risk to humans. Probable Cancer Risk (PCR) values for As, Pb, and Cd exceed acceptable ranges across all demographic groups posing cancer risk to humans particularly children. The present study highlights the need for groundwater treatment and regulatory interventions to mitigate health and ecological risks due to the contamination of heavy metals in Vellore city.

Biochar Derived from Sewage Sludge: The Impact of Pyrolysis Temperature on Chemical Properties and Agronomic Potential

The rising volume of sewage sludge from urbanization poses substantial environmental and public health concerns, underscoring the urgency for the implementation of effective waste management strategies. The objective of this study was to evaluate the influence of pyrolysis temperature on the chemical composition and agronomic potential of biochar derived from sewage sludge. The pyrolysis process was conducted at temperatures ranging from 400 °C to 800 °C, and the resulting biochar was analyzed for pH, electrical conductivity, metal content, and carbon fractions. Additionally, phytotoxicity tests were conducted to assess the impact of the biochar on plant germination. The findings indicated that elevated pyrolysis temperatures resulted in an elevated alkalinity, electrical conductivity, and concentration of alkali metals in the biochar. Conversely, these processes resulted in a reduction in total organic carbon content and an increase in heavy metal content, which may limit the potential for biochar to be used in agricultural applications. The phytotoxicity tests indicated that the biochar produced at lower temperatures (400 °C) exhibited positive effects on plant growth when administered at doses of 5 and 10 t·ha−1. Conversely, the biochar produced at higher temperatures (800 °C) demonstrated significant toxicity. The findings indicate that the pyrolysis temperature is a critical factor in determining the suitability of biochar for agricultural applications. The production of biochar at lower temperatures may offer agronomic benefits, whereas the use of higher temperatures increases stability but is associated with the risk of higher heavy metal concentrations.

A comparative study of the efficacy of alginate lyases in the presence of metal ions elevated in the cystic fibrosis lung milieu

Pseudomonas aeruginosa, a common cause of morbidity in cystic fibrosis, chronically infects the patient's lungs by forming an alginate-containing biofilm. Alginate lyases are polysaccharide lyases that lyse alginate and are, therefore, potential biofilm-disruptive agents. However, cystic fibrosis sputum contains high levels of metals such as iron and zinc. The efficacy of alginate lyases under these conditions of elevated metal concentrations has not been categorically determined. Here, we have assessed the enzyme activity of two exolytic and five endolytic alginate lyases in the presence of metal ions (Fe2+, Zn2+, Mn2+, Mg2+, Ca2+, Ni2+, Cu2+) elevated in the cystic fibrosis lung milieu. Several of these alginate lyases exhibited increased activity in the presence of Ca2+, and the polysaccharide lyase family 7 members studied here exhibited decreased activity in the presence of Zn2+. The enzyme activity of the PL7 alginate lyases from Cellulophaga algicola (CaAly/CaFLDAly) and Vibrio sp. (VspAlyVI) was not affected in the presence of a mix of all the above-mentioned metal ions at the elevated concentrations found in the cystic fibrosis lung milieu. Specific alginate lyases might, therefore, retain the ability to degrade the alginate-containing Pseudomonas biofilm in the presence of metal ions elevated in the cystic fibrosis lung milieu.

Magnetite nanoparticles from representative coal fired power plants in China: Dust removal capture and their final atmospheric emission

Information on the emission of coal combustion-sourced magnetite nanoparticles (MNPs) is lacking, which is critical for their health-related risks. In this study, MNPs in coal fly ashes (CFAs) from various coal-fired power plants (CFPPs) in China equipped with various dust removal devices were extracted and quantified using single particle ICP-MS. The number concentrations of MNPs in CFAs captured by dust removal increased with stage, while their size decreased. Among all the dust removal devices, electrostatic-fabric-integrated precipitators showed the best removal of MNPs. Furthermore, throughout all the coal combustion by-products in a typical CFPP, MNPs in EFA (fly ash escaped from the stack) showed the highest number concentration (1.2 × 107 particles/mg) and lowest size (78 nm). Although the mass of CFA escaping through the stack is extremely low, it still had an emission rate of 1.9 × 1015 particles/h, contributing 3.56 % of the total emissions of MNPs in number. In addition, the purity of MNPs and their associated toxic metals showed a size-dependent variation pattern. As the particle size of MNPs decreased, the proportion of Fe in MNPs increased from 43 % in bottom ash (BA) to 84 % in EFA, while the abundance of trace toxic metals in EFA was 3.3 times higher than that of BA. These MNPs with the highest purity can adsorb elevated concentrations of toxic metals, and can be discharged directly into the atmosphere, posing a risk of synergistic toxicity.