Elevated Concentrations Of Pb Research Articles

Assessment and bioaccumulation of heavy metal contaminants in Golden Mahseer (Tor putitora Hamilton, 1822)

Unpolluted freshwater is a crucial component for maintaining the health of humans. This study aimed to investigate the bioaccumulation and potential health hazards of heavy metal contaminants (Fe, Cd, Cr, Cu, Pb) in water, sediments, and tissues of the golden mahseer fish (Tor putitora) from Zhob River to assess their suitability for human consumption. Samples (soil, water, and fish) were collected from the Zhob River, and Flame Atomic Absorption Spectrometry (FAAS) was employed to measure the concentration of these metals found in soil, water, and various fish body tissues (muscles, skin, gills, and liver). The overall results revealed that water quality parameters, i.e., temperature and pH were found within tolerable ranges, while electrical conductivity and turbidity exceeded the permissible limits of FAO/WHO for fish. Furthermore, this study also identified elevated concentrations of Pb in water and soil, as well as Fe and Cd in soil beyond the standards set by the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA). In contrast, the concentrations of other targeted metals examined in fish body tissues were found below the permissible limits set by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO), indicating the suitability of this fish species for human consumption. The estimated daily intake (EDI) of these targeted metals in various fish body tissues was found to be within the recommended dietary allowance (RDA), suggesting no associated health risks for the local population. Furthermore, both the Target Hazard Quotient (THQ) and Total Target Hazard Quotient (TTHQ) values measured in this study were less than one, indicating the absence of potential non-carcinogenic health risks related to the consumption of this riverine mahseer fish, but combined metal intake may pose potential health risks. Carcinogenic risk assessment for some metals like Cd, Cr, and Pb revealed no cancer risk for consumers. Moreover, our present research observed comparatively high bioaccumulation (BAF) of each targeted metal in the fish liver from both Zhob River water and soil as compared to other body tissues. Multivariate analysis, including the correlation matrix, revealed strong and significant correlations (P < 0.05) among heavy metal pairs (Fe/Cr, Fe/Pb, Cr/Fe, Cr/Pb, Pb/Fe, Pb/Cr). Hierarchical cluster analysis and Principal Component Analysis (PCA) were utilized to trace the origins of these metals, attributing their presence to nearby rock weathering, mining, as well as municipal and agricultural activities. These factors were recognized as potential sources of heavy metal bioaccumulation in riverine fish. Thus, our current study concluded that the Zhob River was contaminated with these heavy metals and emphasized the need to prevent domestic and industrial sewage inflow. The monitoring of these metals in the food chain was also underscored as crucial for reducing all kinds of associated health risks. This study provides the first report on heavy metal distribution in highly abundant and edible mahseer fishes of the Zhob River.

Mixed lead sources in tin metal: Implications for using lead isotopes to study tin artifacts

Methods for provenancing copper, lead, and silver using the isotopic composition of lead are well-established. Lead isotope analysis holds promise for the study of tin metal as well, as long as one accounts for the U-Th-Pb systematics of cassiterite (SnO2) and chaîne opératoire of tin production. Although Precambrian cassiterite may contain 10s of ppm Pb or more (predominantly radiogenic 206Pb), Phanerozoic examples typically contain only a few parts per million Pb. However, all but one of the 133 raw tin ingots excavated from European Bronze Age shipwrecks contains more Pb than could have come from cassiterite alone, as do six of the twelve analyzed tin objects interpreted to have been derived from the ores of southern Africa. Accordingly, almost all tin objects must contain Pb from external cassiterite sources and interpretation of LIA must account for this contamination. The nature of the contaminant (sulfides, U-Th-bearing minerals, silicates) can be inferred from patterns in Pb concentration and LI values. The 3 major sources of Pb that can typically be identified in tin artifacts are original Pb from the tin ore, radiogenic Pb produced in-situ due to U decay, and external Pb added during the cassiterite smelting and ingot production. As cassiterite has high U/Pb but low Th/Pb, the 208Pb/204Pb may be representative of the initial Pb incorporated in the mineral. This is assuming either that no external Pb is added during the ore processing or that the added Pb is from coeval sulfides from the same Pb ore provenance. In such cases 208Pb/204 Pb can be used to estimate a Pb model age, which in turn can be used for provenance estimate of the ingots. If the addition of Pb is from U-Th-mineral contaminants to the ore concentrate, then this will also increase 208Pb/204Pb and point to erroneously young model Pb ages. In such cases, the problem would be evident in positively correlated values of 206Pb/204Pb and 208Pb/204Pb. If Pb concentrations are above a certain threshold (approximately 5 ppm). LIA typical common Pb isotope ratios will be clear indication that external, non-cassiterite Pb, is added to the tin artifact. This tin could be from impurities in the ore (e.g., inclusions in cassiterite, impurities in the ore concentrate, or added during ore smelting and/or metal processing. Overall, elevated Pb concentrations accompanied with non-radiogenic Pb isotopes typical for common Pb, is a clear indication that significant amount of external (contaminant) Pb is added to the tin artifact.

Fractionation and leaching of Cd, Cu, Fe, Pb, and Zn from smelter residues of an old environmental liability in Argentina

An integrated chemical and mineralogical characterization approach was applied to smelter wastes collected from 50-year-old dump sites in Argentina. Characterization included pseudo-total element concentrations, acid generation/neutralization potential, sequential extractions, pH-dependent leaching kinetics, and mineralogical analysis of all residues. These analyses provided detailed information on the reactivity of the minerals in the waste material and associated metal release. Cadmium and Zn were the elements of greatest environmental concern due to their high mobility. On average, the release of Zn and Cd in pH-dependent leaching essays reached 17.6% (up to 5.24 mg g−1) and 52.7% (up to 0.02 mg g−1) of the pseudo-total content, respectively. Moreover, Cd and Zn were also the metals that showed the higher proportions of labile fractions associated to the adsorbed and exchangeable fraction (60–92% for Cd and 19–38% for Zn). Since Cd and Zn concentrations in the residue are not high enough to form their own minerals, a large proportion of these elements would be weakly adsorbed on Fe oxyhydroxides. In contrast, the low release of Cu, Pb and Fe would be associated with these elements being incorporated into the crystalline structure of insoluble or very poorly soluble minerals. Lead is incorporated into plumbojarosite and anglesite. Copper was mainly in association with Fe oxyhydroxides and may also have been incorporated into the plumbojarosite structure. The latter could act as a sink especially for Pb under the acidic conditions of the smelter residue. Despite the elevated concentrations of Pb observed in the residue, it showed a very low mobility (≈0.1%), indicating that it is mostly stabilized. Nevertheless, the smelter residue is a continuous source of metals requiring remediation.

The Relationship Between Metal Exposure and HPV Infection: Evidence from Explainable Machine Learning Methods.

HPV is a ubiquitous pathogen implicated in cervical and other cancers. Although vaccines are available, they do not encompass all subtypes. Meanwhile, metal exposure may elevate the risk of HPV infection and amplify its carcinogenic potential, but studies to further elucidate this relationship are insufficient.This study entailed a cross-sectional analysis utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. The study sample comprised 2765 women. Multivariate logistic regression was employed to examine the association between single metal exposure and HPV infection, weighted quantile sum (WQS) regression was utilized for assessing the mixed metal exposure effect, and the XGBoost + SHapley Additive exPlanations (SHAP) to evaluate the contribution of metal exposure in HPV infection.Multivariate logistic regression analysis indicated that elevated Co concentration was inversely associated with HPV infection (OR 0.891; 95% CI 0.814-0.975), while elevated Pb concentration correlated with an increased HPV infection (OR 1.176; 95% CI 1.074-1.287). Regression analysis of the WQS for mixed metal exposure suggested that the WQS index was potentially linked to an increased likelihood of HPV infection in the positive direction (OR 1.249; 95% CI 1.052-1.482), with no significant association observed in the negative direction (OR 0.852; 95% CI 0.713-1.017). SHAP analysis prioritized the importance of characteristics: number of sexual partners, marital status, poverty-to-income ratio (PIR), Co, Pb, and alcohol consumption.Exposure to Pb was associated with an increase in the incidence of HPV infection, whereas Co exposure demonstrated an inverse relationship. The composite exposure to multiple metals showed a positive association with the prevalence of HPV infection. These findings indicate that exposure to metals could potentially escalate the prevalence of HPV infection.

RETRACTED: A semi-arid climate's use of exploratory data analysis (EDA) as a reliable non-parametric method for geochemical mapping

In this study, exploratory data analysis (EDA) methods, specifically boxplots, were employed to examine the composition of stream sediments in the Collo area of Northeast Algeria. The region's diverse lithological formations, interactions between permanent and temporary watercourses, intermittent flash floods, rugged topography, and fluctuating climatic conditions contribute significantly to data variability. Utilizing the boxplot's capabilities, our analytical approach successfully identified outliers, recorded the actual distribution of data, and determined skewness without the need for prior data processing, often required in conventional statistical studies. The boxplot proved to be an effective tool, offering insights into the geographical distribution of elemental concentrations, including iron (Fe), zinc (Zn), copper (Cu), arsenic (As), chromium (Cr), and lead (Pb). Geochemical mapping, driven by a robust class selection mechanism developed from the boxplot, revealed strong geographical correlations. A notable northeastern anomaly, characterized by elevated concentrations of Pb, Zn, Cu, and As, aligned with known base-metal sulfide and arsenopyrite mineralization sites. Additionally, outlier data for Cr indicated proximity to a plagioclase-lherzolite intrusion and known chromite deposits. The geographical distribution of iron, corresponding with known magnetite and hematite resources, was effectively highlighted using robust class selection based on boxplot analysis. This comprehensive investigation underscores the value of EDA methods in identifying mineralization trends amid the complex variability of the Collo area.

Is the milk we drink safe from elevated concentrations of prioritised heavy metals/metalloids? – A global systematic review and meta-analysis followed by a cursory risk assessment reporting

Milk has been globally recognised as a comprehensive and vital food source for centuries. However, the presence of heavy metals and metalloids (metal(loid)s) in milk is a global problem. As metal(loid)s are present in the soil due to natural geogenic and various anthropogenic activities, these metal(loid)s are bio-transferred into animal feed, which further results in the presence of metal(loid)s in milk due to bio transfer/accumulation. This systematic review collated information from published literature between 2000 and 2021. It focused on the global issue of metal(loid)s in milk, posing potential health risks. These contaminants enter the food chain through the bio-transfer/accumulation process from soil to animal feed to milk. The key metal(loid)s examined are arsenic (As), mercury (Hg), lead (Pb), and cadmium (Cd). A meta-analysis of 66 selected papers revealed the widespread presence of these contaminants in milk samples globally, with Pb being the most studied (43 %). This research estimated metal(loid)s levels or concentrations as 12.71 (95 % Confidence Interval (CI) = 0.16–25.26), 16.09 (95 % CI = 4.31–27.70), 197.04 (95 % CI = 75.28–318.18), 31.67 (95 % CI = 20.14–43.20) μg/kg (ppb) for As, Hg, Pb, and Cd, respectively using Stata™. The metal(loid) concentrations in milk were within the threshold limits other than Pb and Cd. Some studies in America, Africa, and Asia reported elevated Pb and Cd concentrations, raising health concerns. The simulated Risk Quotients (RQ) and Integrated Risk Quotient (IRQ) values generally remain above one, indicating potential human health risks. Notably, the IRQ value increases with more metal(loid)s consideration. Subgroup analysis indicates low-fat milk contains higher metal(loid)s concentrations. While metal(loid)s concentrations in milk largely comply with safety limits, some regions exhibit concerning concentrations. Therefore, continued surveillance to address potential health risks associated with metal(loid)s in milk is necessary to ensure dairy products' safety.

Health risk assessment of potentially toxic elements in the riparian zone of the Sava River (southeastern Europe): effects of high and low water events

This study evaluated the source apportionment and level of contamination with potential toxic elements (PTEs)—As, Cd, Cr, Cu, Ni, Pb and Zn—in a riparian zone of the Sava River by calculating the Enrichment Factor (EF) and the Geo-Accumulation Index (Igeo). The study analysed the non-carcinogenic and carcinogenic health risks to both adults and children in the local population. Soil and sediment samples collected during high and low water events from 12 sites along 945 km of the river were screened. Elevated soil contents of As, Cr, Cu, Ni, and Zn were observed along the middle and lower stretches from Županja (ZUP) to Belgrade (BEO), and an elevated Cu content was detected in the upper stretch Čatež (CAT), highlighting these elements as a potential risk for the human population. Elevated As, Cd Cr, Ni, and Zn levels in the sediment were also detected, with the Ni content three times higher than the Permissible Exposure Limit (PEL) values, indicating high contamination. The study established that As, Cr, and Ni primarily originate from geological sources; Cu, Pb, and Zn are predominantly from anthropogenic sources; and Cd originates from both geological and anthropogenic sources. Although the EF and Igeo varied along the entire river stretch, they were significantly higher for most elements in the lower stretch, indicating intensive anthropogenic contamination and potential health risks. The carcinogenic and non-carcinogenic risks associated with soils and sediments during high and low water events did not imply a potential risk for adults. However, As, Cd, Cr, and Pb potentially pose the greatest non-carcinogenic risk for children in both high and low water events, with ingestion as the main route of exposure. According to our findings, the elevated concentrations of As, Cd, Cr, and Pb in the Sava River basin (SRB) pose a significant potential health risk to the local population based on several factors: the high levels of these elements, their potential contamination risk as determined by the EF and Igeo, and their bioavailability and solubility. Although the cumulative Total Hazard Index (THI) and Total Carcinogenic Risk (TCR) values are low, particularly in the lower stretch of the Sava River, these elements still present a high potential health threat.

Trace metal accumulation through the environment and wildlife at two derelict lead mines in Wales

Trace metal pollution is globally widespread, largely resulting from human activities. Due to the persistence and high toxicity of trace metals, these pollutants can have serious effects across ecosystems. However, few studies have directly assessed the presence and impact of trace metal pollution across ecosystems, specifically across multiple environmental sources and animal taxa. This study was designed to assess the environmental health impacts of trace metal pollution by assessing its extent and possible transfer into wildlife in the areas surrounding two abandoned metalliferous mine complexes in Wales in the UK. Water, sediment, and soil at the mine sites and in areas downstream had notably elevated concentrations of Pb, Zn, and, to a lesser extent, Cd and Cu, when compared to nearby control sites. These high trace metal concentrations were mirrored in the body burdens of aquatic invertebrates collected in the contaminated streams both at, and downstream of, the mines. Wood mice collected in contaminated areas appeared to be able to regulate their Zn and Cu tissue concentrations, but, when compared to wood mice from a nearby control site, they had significantly elevated concentrations of Cd and, particularly, Pb, detected in their kidney, liver, and bone samples. The Pb concentrations found in these tissues correlated strongly with local soil concentrations (kidney: ρ = 0.690; liver: ρ = 0.668, bone: ρ = 0.649), and were potentially indicative of Pb toxicity in between 10 % and 82 % of the rodents sampled at the mine sites and in areas downstream. The high trace metal concentrations found in the environment and in common prey species (invertebrates and rodents) indicates that trace metal pollution can have far-reaching, ecosystem-wide health impacts long after the polluting activity has ceased, and far beyond the originating site of the pollution.

The seasonal variation of Asian dust, anthropogenic PM, and their sources in Dushanbe, Tajikistan

Central Asia's arid climate and growing population make it susceptible to air pollution from mineral dust and anthropogenic sources. To assess the impact of these pollution sources on local air quality, the chemical composition of PM10 aerosol particles was collected within a year at Dushanbe, Tajikistan. Primary sources of the pollutants, their impact on PM10 composition, and their seasonal trends were assessed. The measurement approach employed analysis of trace metals, ions, organic compounds, laboratory investigations, diagnostic ratio calculations, all complemented by positive matrix factor analysis. The results reveal that for about 70% of the year, PM10 levels (80 ± 55 μg m−3 as the annual average) in Dushanbe were higher than the WHO limits, with varying levels during the seasons. Summer concentrations peaked up to 434 μg m−3 due to a combined mineral and road dust influence. Interestingly, winter concentrations reached 152 μg m−3 due to strong contributions (about 64%) from residential heating and fossil fuel combustion, often triggered during sub-10 °C temperatures. Mineral dust events were associated with elevated concentrations of trace metals, including Zn and Pb, alongside organic carbon and high-chain n - alkanes. During such events, Ca/Fe, Ca/Al ratios exceeded those of Saharan dust, suggesting a high salt content in Asian dust, potentially influenced by dried-off lake emissions. It was striking to observe that winter periods exhibited concerning levels of carcinogenic PAHs, such as benzo(b)fluoranthene (<25 ng m−3) and benzo[a]pyrene (<12 ng m−3, BaP), with average values of 4.1 ± 5.9 ng m−3 (BaP) that significantly exceed WHO recommendations. The high PM10 and PAH exposure could pose severe health risks, necessitating collective attention from the local authorities in developing new mitigation strategies concerning the reduction of emissions from residential heating of coal and wood in winter to curb combustion emissions and reduce exposure.

Phytoremediation Potential of Flax Grown on Multimetal Contaminated Soils: A Field Experiment.

The aim of this study was to assess the phytoremediation potential of fiber flax (Linum usitatissimatum L., var. Calista) cultivated in a soil contaminated with multiple metals, under real field conditions. A two-year (2022 and 2023) field experiment was conducted in a site contaminated with elevated concentrations of Cd, Ni, Cu, Pb, and Zn due to mining and metallurgical activities. Three different nitrogen fertilization levels were tested (N0: 0 kg N ha-1, N1: 30 kg N ha-1, N2: 60 kg N ha-1), and both spring and winter sowings were conducted. At full maturity, growth parameters and yields were measured. The phytoremediation potential of flax was assessed in terms of the metal concentrations in the above-ground biomass and of the metal uptake (i.e., the potential removal of the soil metals in g ha-1 and per year). Flax demonstrated a shorter growth cycle, with shorter and thicker plants and higher yields when sown in spring compared to winter sowing. Plant growth and productivity were not evidently influenced by additional nitrogen fertilization during plant growth. The cadmium bioaccumulation factor was 1.06, indicating that flax accumulates this metal. For Ni, Cu, Pb, and Zn, the corresponding values were 0.0, 0.04, 0.004, and 0.02, suggesting that this crop excludes these metals. The order of the higher uptake in plant tissues was as follows: Zn > Pb > Cd > Cu > Ni. In conclusion, flax demonstrated tolerance to heavy metals in the soil, effectively supporting soil restoration through cultivation. Additionally, flax showed potential as a cadmium accumulator while excluding nickel, copper, lead, and zinc.

An Evaluation of Long-Term Contaminated Soil from a Manufactured Gas Plant for in Situ Biodegradation Potential and as a Source of Ferrocyanide-Degrading Bacteria

Despite the high abundance and potential toxicity of ferrocyanide in the environment, data on the bioremediation of these complexes in contaminated soils are missing. In this study we isolated forty bacterial species presented in soil highly contaminated with ferrocyanide complexes, originating from a Manufactured Gas Plant (MGP). All bacterial strains were resistant to ferrocyanide (500 mg L−1). Six isolates showed better growth in the presence of ferrocyanide and were able to use it as a sole nitrogen source. One of them was able to assimilate ferrocyanide‐derived nitrogen and carbon. The strains varied in their tolerance to the ferrocyanide. The Minimum Inhibitory Concentration (MIC) values determined in the rich medium ranged from 1400 mg L−1 to 2000 mg L−1 and in all cases were greater than those set on the minimal medium. Molecular analysis revealed that the investigated isolates had the highest similarity to the Bacillus and Rummeliibacillus lineages. Rummeliibacillus was recognized for the first time for its ferrocyanide-degrading potential. Soil samples collected from MGP sites indicated that the overall indigenous population of microorganisms was low. Total cyanide content ranged from 220 mg kg−1 to 346 mg kg−1. Additionally, elevated Pb concentrations and an imbalanced C:N:P ratio were observed. Our study provides new information about the presence of a well-acclimated bacterial community associated with long-term ferrocyanide-contaminated soil. This bacterial community could play an important role in MGP site bioremediation processes and has the potential for application for other bioremediation purposes; however, it is likely limited due to unfavorable environmental conditions.

Uncontrolled Post-Industrial Landfill-Source of Metals, Potential Toxic Compounds, Dust, and Pathogens in Environment-A Case Study.

The aim of this case study was the evaluation of the selected metals' concentration, potential toxic compound identification, cytotoxicity analysis, estimation of the airborne dust concentration, biodiversity, and number of microorganisms in the environment (leachate, soil, air) of the biggest uncontrolled post-industrial landfills in Poland. Based on the results obtained, preliminary solutions for the future management of post-industrial objects that have become an uncontrolled landfill were indicated. In the air, the PM1 fraction dominated, constituting 78.1-98.2% of the particulate matter. Bacterial counts were in the ranges of 9.33 × 101-3.21 × 103 CFU m-3 (air), 1.87 × 105-2.30 × 106 CFU mL-1 (leachates), and 8.33 × 104-2.69 × 106 CFU g-1 (soil). In the air, the predominant bacteria were Cellulosimicrobium and Stenotrophomonas. The predominant fungi were Mycosphaerella, Cladosporium, and Chalastospora. The main bacteria in the leachates and soils were Acinetobacter, Mortierella, Proteiniclasticum, Caloramator, and Shewanella. The main fungi in the leachates and soils were Lindtneria. Elevated concentrations of Pb, Zn, and Hg were detected. The soil showed the most pronounced cytotoxic potential, with rates of 36.55%, 63.08%, and 100% for the A-549, Caco-2, and A-549 cell lines. Nine compounds were identified which may be responsible for this cytotoxic effect, including 2,4,8-trimethylquinoline, benzo(f)quinoline, and 1-(m-tolyl)isoquinoline. The microbiome included bacteria and fungi potentially metabolizing toxic compounds and pathogenic species.

Assessing benthic ecological status of Kaduvaiyar estuary, southeast coast of India – Biotic indices approach

The Kaduvaiyar estuary located on the Southeast coast of India in Nagapattinam is facing various human-induced pressures, making it highly affected by human intervention. To evaluate the ecological quality of the Kaduvaiyar estuary and its coastal region, an extensive survey was conducted. The assessment employed different statistical analyses, specifically the AMBI and M-AMBI biotic indices. Through PCA analysis, it was confirmed that St-1 exhibited a higher similarity level of Clay and TOC. Furthermore, the CCA analysis demonstrated the presence of pollution-tolerant and opportunistic polychaetes species, such as Capitella capitata, Cossura coasta, Prionospio pinnata, and Notomastus sp., in St-1 and St-2. These areas showed elevated concentrations of heavy metals, including Fe, Pb, and Mn. This trend was also evident in the w-statistics, where the negative values (−0.08 and −0.105) indicated the highly polluted nature of St-1 and St-2. Substantiating this, the AMBI values (ranging from 1.86 to 4.17) suggested that the stations (St-1 to St-3) were slightly to moderately disturbed. The M-AMBI result (ranging from 0.43 to 0.44) indicated a clear signal of the disturbed nature and moderate ecological condition of stations (St-1, St-2). These stations are located near urban and harbor activities, which likely contribute to their altered state. However, it is essential to subject the reference conditions proposed for the Kaduvaiyar estuary to further evaluation in upcoming studies. Additional research will help gain a more comprehensive understanding of the estuary's ecological health and establish a solid basis for comparison with future assessments.

An Assessment of Metal Pollution in the Surface Sediments of an East Antarctic Lake

ABSTRACT This study discusses the metal concentrations and sedimentological data from Lake L55, a dried, land-locked lake from Schirmacher Oasis, East Antarctica. Toxic metals in sediments are a major threat to the environment. Twenty-five surface sediment samples were analyzed for the presence of fifteen metals. The sedimentological data indicates that the sediments are predominantly sandy with low concentrations of silt and clay. The chemical weathering index for the sediments reflects low degree of weathering. Negligible concentrations of organic content were present in the sediments owing to the cold and dry conditions of the study area. The environmental pollution indices indicate elevated concentrations of Ba, Zn, As and Pb in the sediments. Barium could be supplied by the weathering of the quartzofeldspathic catchment rocks, while Zn, As and Pb could be supplied from the fuel burning for power generation and logistical activities, paint residue, and battery waste. The sediment quality guidelines were calculated for the sediments, and they indicate that the sediments have a 21% risk of being toxic. The pollution load index, potential ecological risk index (PERI) and toxic risk index (TRI) values suggest low toxic risk in the sediments of the lake.

Contamination of urban soils in a historical mining town of northern Chile

In northern Chile, economic activities related to mining and thermoelectric energy have existed in the city of Tocopilla since the early 1900s and metal concentrations in soils have likely been altered by historic anthropogenic activities. To assess the concentrations of Cu, Zn, Pb, Ni, Co, and Cr in urban soils of Tocopilla, a total of 70 superficial (2 cm) and 70 deep (20 cm) soil samples were collected in 2014. Furthermore, to analyze concentration changes in soils over time, 18 superficial (5 cm) samples were collected in 2020–2021. A numerical evaluation (geoaccumulation index, and enrichment factor), principal component analysis, and spatial distribution approach were applied to infer geogenic and anthropogenic influence on the concentrations of these elements. The main conclusions of this research indicate that urban soils of Tocopilla contain geogenic Cu, Zn, Pb, Ni, Co and Cr. However, elevated concentrations of Cu, Zn, and Pb cannot be attributed to a geogenic origin alone, as a proportion of their enrichment is considered to be anthropogenically sourced. The contamination of anthropogenic elements has been found to be related to historic copper mining and thermoelectric energy production. Furthermore, when compared to other sites globally, median concentrations of Cu (945 mg/kg in 2014 and 823 mg/kg in 2020) and Zn (305 mg/kg in 2014 and 196 mg/kg in 2020) in superficial urban soils are among the highest worldwide. Regarding 2020–2021 sampling, Zn and Pb concentrations have increased, while Cu, Cr, Co, and Ni have remained similar to the 2014 samples.

Lead exposure is related to higher infection rate with the gapeworm in Norwegian house sparrows (Passer domesticus)

Anthropogenic pollution is identified as an important threat to bird and other wildlife populations. Many metals and toxic elements, along with poly- and perfluoroalkyl substances (PFASs) are known to induce immunomodulation and have previously been linked to increased pathogen prevalence and infectious disease severity. In this study, the house sparrow (Passer domesticus) was investigated at the coast of Helgeland in northern Norway. This population is commonly infected with the parasitic nematode “gapeworm” (Syngamus trachea), with a prevalence of 40–60 % during summer months. Gapeworm induces severe respiratory disease in birds and has been previously demonstrated to decrease survival and reproductive success in wild house sparrows. The aim of this study was to investigate whether a higher exposure to pollution with PFASs, metals and other elements influences gapeworm infection in wild house sparrows. We conducted PFASs and elemental analysis on whole blood from 52 house sparrows from Helgeland, including analyses of highly toxic metals such as lead (Pb), mercury (Hg) and arsenic (As). In addition, we studied gapeworm infection load by counting the parasite eggs in faeces from each individual. We also studied the expression of microRNA 155 (miR155) as a key regulator in the immune system. Elevated blood concentrations of Pb were found to be associated with an increased prevalence of gapeworm infection in the house sparrow. The expression of miR155 in the plasma of the house sparrow was only weakly associated with Pb. In contrast, we found relatively low PFASs concentrations in the house sparrow blood (∑ PFASs 0.00048–354 μg/L) and PFASs were not associated to miR155 nor infection rate. The current study highlights the potential threat posed by Pb as an immunotoxic pollutant in small songbirds.

Vertical distribution and contamination assessment of heavy metals in the vadose zone of a 50-year-old smelter dumpsite, San Antonio Bay, Argentina

This research aimed to assess the contamination levels and mineralogical association of heavy metals in the vadose zone beneath smelter residues that were freely deposited over natural sediments from the 1960 s to the 1980 s. The results revealed elevated concentrations of heavy metals, particularly Fe, Pb, Zn, Cu, and Cd. The highest concentrations were found within the superficial layer, corresponding to the smelter slag (203,703 – 219,998 mg kg−1 Fe; 73,708 – 136,390 mg kg−1 Pb; 18,922 – 29,484 mg kg−1 Zn; 6473 – 7887 mg kg−1 Cu; 20 – 48 mg kg−1 Cd). This residue is an acidic material mainly constituted by secondary sulfates and oxyhydroxides. Although concentrations decreased with depth, the levels of these metals remained higher than the background even at depths of 300 cm. Precipitation of secondary minerals (plumbojarosite, anglesite, Zn-sulfates, and Fe oxydroxides) from the percolating leachates was detected in the vadose zone based on SEM and EDS analysis. According to their vertical distribution, Cd and Zn showed a higher mobility than Cu, Fe and Pb, which were primarily concentrated at the surface layer. The geo-accumulation index (Igeo) was Pb > Cu > Zn > Cd > Ni. The vadose zone is severely polluted and represents a very high risk to the environment based on the ecological risk factor (Eri) and risk index (RI). The metals that contribute most to this condition are Pb > Cd ≈ Cu > Zn. Given the severity of the situation, remediation of the study area is recommended.

Trace element of small lake sediments sensitively recorded environmental changes in the watershed: Implications for mining history and urbanization

Lake sediments serve as a sink for trace elements and provide a record of watershed changes resulting from anthropogenic activities and natural processes. In this study, eight trace elements in the sediments of Lake Aha, an urban lake in Guiyang City, Southwest China, were investigated to reveal the effects of historical coal mining and rapid urbanization in the watershed. Results showed that the median contents of measured trace elements in order of Zn (220.00 mg/kg) > Ni (98.16 mg/kg) > Cr (70.26 mg/kg) > Cu (66.20 mg/kg) > As (58.14 mg/kg) > Co (41.66 mg/kg) > Pb (28.33 mg/kg) > Cd (1.39 mg/kg). Except for Cr and Pb, the median concentrations of Cd, As, Zn, Ni, Co, and Cu were 4.64, 2.33, 2.00, 1.92, 1.81, and 1.09 times higher than regional natural background values respectively. Trace element contents in sediments of the center of the lake were significantly higher than in the rest of the sediment cores, resulting from relatively stable hydrodynamic processes in the region. Vertical variation of trace elements indicated that the fluctuations in the intensity of coal mining activities in the tributaries were effectively tracked by variations of trace element levels in the middle layer sediments of the Youyu River and Baiyan River estuaries. The elevated concentrations of Pb in the surface sediments of the Jinzhong River estuary reflected the rapid urbanization in the basin over the past 20 years. PMF analysis demonstrated that As, Cd, and Pb in sediments were from a mixture of natural and urban activities, and Cu, Zn, Ni, and Co originated from coal mining. This study provides important information for comprehending the anthropogenic activities of small-scale lakes and historical environmental changes.

Variability of rare earth and heavy metal elements in a representative alluvial depositional system.

Heavy metals (Ni, Cr, W, Cd, and Pb) and rare earth elements (REE) were investigated in the flood plain sediments of an island of the lower Yangtze River near Nanjing to determine how the vertical distribution of heavy metals could be affected by natural sedimentation processes and anthropogenic contamination. Stratigraphic analyses of magnetic susceptibility and the mean grain size distribution of the deposits enabled us to identify layers associated with a relatively high influx of suspended sediments that resulted in sudden changes in the concentrations of heavy metals. The results show that layers associated with high sediment influx (0.8m depth) displayed low concentrations of Cr, Ni, W, and Cd that were mainly lithogenic in origin. The Post Archean Australian Shale (PAAS) normalized REE patterns in the flood plain cores were enrichment in Ce and Eu relative to PAAS, indicating that the sediments were most likely derived from a mixture of sediments and not from an anthropogenic source. Sharp increases in Y/Ho ratios, as well as heavy metal (Cd, Cr, Ni, and W) and Y concentrations were observed in the uppermost layer that could have been deposited from the rapid transport of sediment-laden, contaminated waters. The temporal (vertical) trends in Pb concentrations may be strongly influenced by coal burning. Elevated Pb concentrations (350ppm and 1000ppm) correlate with high magnetic susceptibility (> 200 m3 × kg-1) and the history of thermal power plant (1910-2002) activity. The anthropogenic inputs of Pb were, however, not diluted by high suspended sediment loads, which supports the argument that Pb was derived from fly ash.

Origin and Tectonic Implications of I-type Granites, North Delhi Fold Belt, NW, India: Insights from Whole Rock Geochemistry and Mineral Compositions

Abstract A comprehensive whole-rock geochemical and mineral chemistry study was carried out of granites from the Narnaul and surrounding isolated hills of North Delhi Mobile Belt, NW India to constrain their genesis, and tectonic environment. The distinctive features of granites are meta to peraluminous nature and decreasing trend of P2O5 with high SiO2 (&amp;gt;71%) ascribed to its metaigneous origin. In detail the chemical diversity of the studied samples is reflected by their affinity to Calc-alkaline to shoshonite series with high K2O/Na2O (mostly&amp;gt;1), low MgO (&amp;lt; 0.11%) and variation in Mg# (upto 0.5) and maficity with increasing SiO2. The positive Eu anomalies, high LILE, highly enriched LREE (La/Sm = 4.13–19.33) pattern and comparatively elevated concentrations of Cs, La, Ta, Dy, Zr, Pb and Yb suggest different episodes of magmatic differentiation. Our data indicate that melting of older subduction-related igneous rocks and the underwent fractional crystallization in hydrous conditions is the possible mechanism for the generation of I-type granites in collisional tectonic setting.