Concentrations Of Pb Research Articles

Environmental assessment of toxic heavy metals and natural radionuclides in irrigation water from Rustenburg, South Africa

Water is a transparent, tasteless and odourless inorganic compound, essential for life and sustainable development. It is important for food and energy production, socio-economic growth, healthy ecosystems and human existence. Global attention is given to water quality monitoring due to the role it plays in human exposure to different kinds of contaminants, including radioactive and toxic contaminants from industrial, agrochemicals, mining and other anthropogenic activities. This work presents the results of measured natural radionuclides and toxic heavy metals in Rustenburg, and their associated non-carcinogenic and carcinogenic risk. The average concentrations of Cd, Cu, Co, Fe, Ni, Mn, Pb and Zn are 0.00007 mg/l, 0.0087 mg/l, 0.0033 mg/l, 0.0636 mg/l, 0.0052 mg/l, 0.0217 mg/l, 0.0003 mg/l and 0.0047 mg/l respectively and are below the safe limit of toxic heavy metals in water. The activity concentration of 40K and 238U ranges from 7.07 Bq/l to 13.2 Bq/l and 1.24 × 10−04 Bq/l to 1.09 × 10−02 Bq/l, with a mean activity concentration of 11.6 Bq/l and 2.78 × 10−03 Bq/l respectively. 232Th was not found in all measured water samples. The estimated average committed effective dose from ingestion of natural radionuclides was observed to be below 170 μSv/yr for 40K, 120 μSv/yr for 232Th and 238U, and a total of 290 μSv/yr reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. The assessment of human health risks resulting from exposure to toxic heavy metals shows negligible carcinogenic and non-carcinogenic health risks to the exposed population, making the water sources from which the sample was collected, safe for agricultural and domestic use. The obtained results will also serve as reference data for future environmental studies.

Application of melting technology in the treatment of nonferrous hazardous waste residues

ABSTRACT In order to find a more effective treatment method for non-ferrous hazardous waste residues, the research proposed the fusion disposal technology of collaborative resource residues. The empirical results showed that the leaching concentrations of Cr and Pb of the molten products of the resource residue were maintained at 0 mg/L, and the final leaching concentrations of most heavy metals were within 0.10 mg/L, which showed low toxicity to the environment. The above results show that the fusion disposal technology of collaborative resource residue is an effective treatment method. The fusion disposal technology not only reduces the heavy metal leaching concentration of non-ferrous metals, but also promotes the development of hazardous waste residue treatment technology.

Study on the source identification and migration and transformation characteristics of heavy metal pollution in sediments of Chaohu Lake Tongyang River Basin.

Heavy metal pollution in soil and groundwater is difficult to detect in time because of its long-term accumulation. This poses a severe hazard to the ecosystem security in polluted areas. Considering the Tongyang River Basin of the Chaohu Lake water system as the research object, various pollution evaluation methods, Geographic Information System (GIS) source analysis models, adsorption and desorption experiments, and mathematical models were used. Based on the data of the heavy metal content in the soil and river sediments in the study area, regional heavy metal pollution evaluation, spatial distribution characteristics, source identification, and lake loss analysis were conducted to evaluate the current situation of environmental pollution, pollution sources, and migration and transformation of heavy metals in the basin. The results show that the heavy metals in the soil of the basin are mainly distributed from the southwest to the northeast and the island distribution to the east of Tongyang Town. The Cd, Cu, Zn, and Pb concentrations are higher in the sediment than in the soil. The Unmix analytical model was established. The natural source of heavy metals in the Tongyang River Basin and the composite pollution source of traffic-production and life showed a high correlation. According to the one-dimensional steady-state model, the concentrations of the heavy metals are in the following descending order: Zn, Cr, Pb, Cu, Ni, and Cd. The amounts of these elements entering the lake annually are 1993.04, 1028.1, 372.47, 301.72, 308.80, and 19.46 kg, respectively (a total of 4023.6 kg).

An assessment of in vitro lead (Pb) bioaccumulation of Dianthus chinensis L. (Chinese pink).

Heavy metals (HM) also known as potentially toxic elements (PTEs), are well-known environmental pollutants, among which lead (Pb) is a widespread and hazardous soil contaminant. Its removal from soil sediments is often difficult to achieve. In this study, in vitro experiments were conducted to investigate the bioaccumulation capability of Dianthus chinensis L. in solid and liquid Murashige and Skoog (MS) medium supplemented with varying concentrations (0, 10, 100, and 200µM) of Pb as lead nitrate [Pb(NO3)2] for 30days. The objectives of the study were to assess the efficiency of the selected plant as a bio-accumulator in the in vitro system and to obtain data on morphological, biochemical, and molecular changes during Pb salt-induced stress. Significant growth patterns of initial growth promotion up to 100µM lead nitrate supplemented medium were observed, with maximum shoot length and biomass production along with remarkable lead bioaccumulation. Molecular studies on in vitro raised plantlets confirm the high degree of genetic uniformity (98.3%) of the selected plants after a considerable duration (30days) of Pb exposure. Biochemical parameters revealed significant stress effects, including a 284% reduction in total chlorophyll content, altered carotenoid, and proline level during the study. The experiment revealed the high tolerance capacity of D. chinensis to Pb salt and its bioaccumulation potential (397.33mg/kg). This increases the possible use of such an ornamental and floriculture plant as a prospective candidate for the efficient removal of soil Pb pollutants, as they can remediate soils, coupled with aesthetic and profitable outcomes for the growers.

Biosorption of Pb(II) Ions through Nanostructured Teff Straw based Magnetized Activated Biocarbon: Aspects on Modeling, Optimization, and Kinetics

<p>In this study, activated carbon (AC) was prepared from teff grass straw via chemical activation and microwave-assisted pyrolysis. The AC was modified by magnetization followed by it was characterized by particle size, FTIR, XRD, thermogravimetric study, pore size, and magnetic properties. Further, it was evaluated for its adsorptive removal performance of lead (II) ions from aqueous solution. A statistical model was developed by response surface method (RSM) and the crucial parameters, concentration of initial Pb(II), biosorbent loading, solution pH, and contact time were optimized for maximizing the adsorption of Pb(II) ions. The optimal values were 95.36 mg/L, 0.656 g/100 mL, 5.5, and 88.7 min, respectively for aforementioned parameters. Under the optimal condition, the Langmuir isotherm exhibited the most accurate correspondence with the obtained experimental data. The findings from the kinetic analysis were found to be statistically fit to the pseudo-2nd order model.</p>

Bacillus altitudinis Mediated Lead Bioremediation for Enhanced Growth of Rice Seedlings.

Lead (Pb) is a hazardous environmental pollutant that threatens soil health, water quality, and agricultural productivity. Plant growth-promoting rhizobacteria (PGPRs) mediated bioremediation is considered as an eco-friendly approach for agro-environmental sustainability. This study investigated the Pb bioremediation potential of Bacillus altitudinis (IHBT-705). The results revealed that IHBT-705 strain tolerated upto 15mM of Pb, possessed 96% Pb bioaccumulation efficiency, and also maintained its plant growth-promoting (PGP) traits under Pb stress. Furthermore, IHBT-705 strain treated with 15mM Pb solution (IHBT-W) and soil containing 15mM Pb treated with IHBT-705 inoculum (IHBT-S) ameliorated the detrimental effects of Pb stress. Both IHBT-W and IHBT-S treatment significantly improved the shoot length, root length, total roots, chlorophyll content, and antioxidants enzyme activity of the rice seedlings as compared to the seedlings treated with 15mM Pb solution (Pb-W) and soil containing 15mM Pb (Pb-S). Also, IHBT-W and IHBT-S treatment decreased the Pb content in the rice plant by 97 and 96% over their respective Pb-W and Pb-S plants. Overall, our research underscores the remarkable Pb bioremediation potential of IHBT-705, offering a promising avenue for dual function, i.e. improving soil health and promoting plant growth under Pb contamination.

Assessment of Ecological Hazards in the Inaouen Wadi and Its Tributaries Using the Presence of Potentially Toxic Elements in Its Sediments

Inaouen wadi is the second largest tributary of the Sebou river, one of Morocco’s major rivers, which holds significant economic and social importance. Unfortunately, this watercourse is severely impacted by pollution from various human activities, particularly industrial sources. However, available data on the presence of potentially toxic elements (PTEs) that could harm human health in this region remain limited. PTEs pose major environmental risks due to their toxicity, persistence, and bioaccumulation. This study aimed to assess the concentrations of PTEs in the sediments of Inaouen wadi and its main tributaries based on sediment samples collected from 12 locations in 2019. The concentrations of Cd, Pb, Cr, Ag, Al, Cu, Fe, and Zn were measured using inductively coupled plasma atomic emission spectroscopy (ICP–AES), and sediment contamination levels were evaluated using multiple indices: the enrichment factor (EF), the geo-accumulation index (Igeo), the potential ecological hazard index (RI), and the modified ecological risk index (MRI). The results indicate that concentrations of Pb, Cd, Cr, Cu, Fe, and Zn are significantly influenced by urban discharges, particularly at sites S1, S3, and S5 near the cities of Taza and Oued-Amlil. The maximum values recorded were 7.01 g/kg for Pb, 0.9 g/kg for Cd, 0.1 g/kg for Cr, 19.9 g/kg for Fe and 1.9 g/kg for Zn. The enrichment factor (EF) revealed anthropogenic sources of Fe and Pb, confirming the human origin of these elements. The geo-accumulation index (Igeo) showed that the areas around stations S1, S3, and S5 are highly contaminated by Pb, Cd, and Fe, a finding also supported by the MRI. The study identified potential ecological risks at stations S1, S3, and S5, highlighting the urgent need for improved pollution management practices to mitigate environmental risks.

Contamination Features and Quantitative Source Apportionment of Potentially Toxic Elements in the Urban Surface Soil, the Case of Hamedan, West of Iran.

In this study, a total of 180 surface soil samples were collected from a control area and residential, commercial, and industrial regions of Hamedan, Iran during the fall season in 2023. Contents of analyzed elements were then determined using ICP-OES. The results illustrated that the average contents of As, Cd, Cu, Mn, Ni, and Pb were 1.17-2.26 times greater than those reported as local background values, while the mean contents of As, Cd, and Cu were respectively 3.41, 1.25, and 1.00 times greater than the background contents for Iran by implying the possible human sources of these PTEs. The cumulative average ecological risk value with 81.9, demonstrated moderate ecological risk across the study area. The results of source apportionment showed that the PTEs contamination in the soil of the study area mainly originates from the anthropogenic activities (65.6%) and traffic emissions as the primary pollution source (47.3%) had the highest contribution to the PTE pollution in the study area. In conclusion, by providing a useful approach to identifying the sources and contributions of toxic elements across different functional areas, this study has the potential to guide future efforts aimed at managing and mitigating the pollution caused by metal elements.

Adsorption isotherms and removal of lead (II) and cadmium (II) from aqueous media using nanobiochar and rice husk

Removal of Cd(II) and Pb(II) from aqueous solutions is a challenging task and the search for novel adsorbents is underway. This study examined the efficiency of nanobiochar (NB) and rice husk (RH) in the adsorption and removal of Cd(II) and Pb(II) from water. The effect of various physicochemical parameters such as initial pH, initial Cd and Pb concentration, adsorbent dosage, and contact time were tested. SEM/EDX images confirmed the adsorption of Pb and Cd with surface physical and chemical changes. The maximum Pb removal was noted at pH 6 using NB (96%) and at pH 8 for RH (90%), and the maximum Cd removal by NB was recorded at 8 pH (91%) and by RH at pH 6 (87%). The decline in adsorption intensity at lower pH suggested protonation of the adsorbent surface causing cation-cation repulsion. Most of the adsorption occurred within the initial 60 min. A continuous gradual increase in the adsorption with time suggested multilayer formation. Of the three isotherms, the Freundlich model fits the present data best, implying an infinite surface coverage and indicating the potential for multilayer adsorption of Pb and Cd on the surfaces of RH and NB adsorbents. In conclusion, this study highlights the promising potential of NB as a cost-effective adsorbent for the removal of Cd and Pb ions from aqueous solutions.

Implications of Lead (Pb)-Induced Transcriptomic and Phenotypic Alterations in the Aged Zebrafish (Danio rerio).

Lead (Pb) is a well-known neurotoxin with established adverse effects on the neurological functions of children and younger adults, including motor, learning, and memory abilities. However, its potential impact on older adults has received less attention. Using the zebrafish model, our study aims to characterize the dose-response relationship between environmentally relevant Pb exposure levels and their effects on changes in behavior and transcriptomics during the geriatric periods. We exposed two-year-old zebrafish to waterborne lead acetate (1, 10, 100, 1000, or 10,000 µg/L) or a vehicle (DMSO) for 5 days. While lower concentrations (1-100 µg/L) reflect environmentally relevant Pb levels, higher concentrations (1000-10,000 µg/L) were included to assess acute toxicity under extreme exposure scenarios. We conducted adult behavior assessment to evaluate the locomotor activity following exposure. The same individual fish were subsequently sacrificed for brain dissection after a day of recovery in the aquatic system. RNA extraction and sequencing were then performed to evaluate the Pb-induced transcriptomic changes. Higher (1000-10,000 ug/L) Pb levels induced hyperactive locomotor patterns in aged zebrafish, while lower (10-100 ug/L) Pb levels resulted in the lowest locomotor activity compared to the control group. Exposure to 100 µg/L led to the highest number of differentially expressed genes (DEGs), while 10,000 µg/L induced larger fold changes in both directions. The neurological pathways impacted by Pb exposure include functions related to neurotransmission, such as cytoskeletal regulation and synaptogenesis, and oxidative stress response, such as mitochondrial dysfunction and downregulation of heat shock protein genes. These findings emphasize a U-shape dose-response relationship with Pb concentrations in locomotor activity and transcriptomic changes in the aging brain.

Biomonitoring of Mercury and Lead Levels in the Blood of Children Living near a Tropical River Impacted by Artisanal and Small-Scale Gold Mining in Colombia.

(1) Background: Mercury and lead contamination resulting from various anthropogenic activities represents a global environmental problem and a considerable risk to the health of the human population. (2) Methods: The objective of this research was to evaluate the concentrations of mercury (Hg) and Lead (Pb) in the blood of the child population in the municipalities in the Atrato River basin using a direct Hg analyzer and graphite furnace atomic absorption spectrometry. (3) Results: In total, 171 children (5-14 years of age) were taken into account, and 18.71% (32) of the children had concentrations of Hg and Pb above the permissible values established by the WHO. In the municipality of UN, 19 children had blood Hg concentrations between 5.29 and 17.71 μg/L. In CA, two children had concentrations of 5.03 and 8.43 μg/L, separately. In the case of Pb, seven children showed concentrations between 3.60 and 4.83 μg/dL in the municipality of RQ, three in UN (3.59, 3.61, and 4.60 μg/dL), and one in Carmen de Atrato (5.47 μg/dL). (4) Conclusions: The levels of Hg and Pb in the blood of children living in the riparian areas of the Atrato River basin are related to gold mining activities in the basin and the consumption of contaminated fish.

Pollution Characteristics, Risk Assessment and Source Identification of Heavy Metals in Surface Sediments from the Cage Fish Farm of Poyang Lake, China

ABSTRACT With the development of cage culture, increasing heavy metals concentrations are being taken into sediments. The accumulation of heavy metals in sediments may cause long term environmental issues and pose threat to human health. Fourteen surface sediment samples were collected to assess the contamination status and potential ecological risk of heavy metals, and identify their potential sources from the cage fish farm of Poyang Lake. The concentrations of Cu, Pb, Zn, Cd, Cr, As and Ni in the sediments were measured by ICP-MS. The geo-accumulation index, enrichment factor and potential ecological risk index were implied to evaluate their pollution levels and ecological risk. The principal component analysis was used to identify their potential sources. The results showed that all of the examined heavy metals content exceeded their background values. These heavy metals (except Cd, Cr and As) presented moderately polluted level. Cu showed significant enrichment, Zn, Pb and Ni exhibited moderate enrichment, As and Cd presented minimal enrichment. Cu and Cd posed a moderate ecological risk, and the other heavy metals posed a low ecological risk. The comprehensive potential ecological risk was associated with considerable ecological risk. Cage culture, smelting, mining and agriculture activities were their primary pollution sources.

Comparison of 35 trace elements content in malignant breast tumors with their content in the normal female mammary gland: Original data and a mini-review

Objective: In many countries, including Russia, breast cancer ranks first in the incidence of cancers in women. The etiology of this disease remains largely unclear, but there is evidence indicating that disturbances in the somatic homeostasis of trace elements may be involved in the process of oncogenesis. Therefore, this study was aimed at identifying changes in the content of trace elements during malignant transformation of breast tissue.Methods: For this purpose, an effective method of small sample analysis by means of inductively coupled plasma mass spectrometry was developed. The method makes it possible to determine the content of 35 trace elements in microsamples (with mass ≥ 10 mg) of breast tissue obtained by puncture biopsy. With the help of this technique, the samples of cancerous (n = 43) and normal (n = 38) breast tissue were studied.Results: In malignant breast tissue, the content of Al, As, B, Cd, Co, Cs, Cu, Mg, Mn, Mo, Ni, Rb, Se, Sr, Ti, Tl, U, V, Zn, and Zr was higher, while the content of Ge, Pb, Sb and Th was lower than in healthy gland tissue. All the identified differences were statistically significant.Conclusions: The significant disruption of somatic homeostasis of trace elements resulting from malignant transformation of breast tissue has been described, but its cause has not been determined, so additional research is required. Further the method we employ, which we have developed and described here, requires tissue samples weighing only a few milligrams, so it is possible to use it with tissue obtained from puncture tissue biopsies.

Efficient remediation of cadmium and lead contaminated soil in coal mining areas by MICP application in hydrothermal carbon-based bacterial agents: Nucleation pathways and mineralization mechanisms

The development of industrial mining has resulted in a large amount of Cd and Pb polluting the soil in mining areas, and leads to adverse health effects on the life of both plants and animals. Here, a soft template method was conducted to prepare hydrothermal carbon (HC) with regular morphology, which assisted with Bacillus pasteurii to induce calcite precipitation for decontamination of mining soil. Soil remediation experiments over 30 days of remediation with an HC microbial agent (HCMA) resulted in 89.4% and 87.8% decrease in the amount of leached Cd and Pb, respectively. The content of exchangeable Cd and Pb decreased by 76.1% and 81.0%, respectively. At the same time, soil fertility significantly improved. The electrostatic potential and surface charge distribution of extracellular polymeric substances (EPS) and sodium citrate (NaCit) were analyzed using DFT simulations, their nucleophilic and electrophilic regions were determined, and the nucleation mechanism was determined. The DFT results indicated that the oxygen-containing groups of EPS and NaCit had strong negative electrostatic potential and electronegativity, which could cause Cd2+, Pb2+, and Ca2+ to aggregate on their surfaces. They also combined with CO32− produced by urease during the decomposition of urea, resulting in Cd2+ and Pb2+ being encapsulated by calcium carbonate to form a coprecipitate. X-ray diffraction analyses revealed that the precipitate was mainly calcite calcium carbonate, which is more stable and less prone to secondary leaching of HMs. The gathered data prove the significant role of HCMA in remediation of mining soil contaminated with Cd and Pb.

Enhanced Pb(II) extraction using a novel chitosan/pectin/carbon composite adsorbent for solid-phase extraction

ABSTRACT This research aimed to present the development of chitosan/pectin/carbon (CPC) materials as adsorbents in the solid-phase extraction (SPE) of Pb(II) from river water samples. The CPC adsorbent shows active groups effectively binding Pb(II) ions. The characterisation included using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDX) to analyse functional groups and evaluate surface morphology with elemental composition. SPE parameters were systematically optimised to enhance adsorption-desorption efficiency, including pH 4.0, Pb(II) concentration of 5 mg L−1, flow rate of 13.3 mL min−1, elution flow rate of 12.8 mL/min using nitric acid (HNO3), a sample volume of 25 mL, eluent volume of 1 mL and concentration at 1.0 M. The results showed that the implementation of the refined CPC-based SPE method for Pb(II) analysis in water samples obtained a recovery range of 101% to 103%, accompanied by a significant 25-fold concentration enrichment of Pb(II). Moreover, the adsorption concentration increased from undetectable levels to 1.27–2.48 mg L−1, reporting the efficacy of the CPC-based SPE method for sensitive and accurate Pb(II) analysis in environmental samples.

Impact of ceramic packaging on the quality and safety of Armenian fermented dairy product Matsoun

Background: Packaging is essential for food safety, as it acts as a barrier against contaminants that can cause spoilage and affect human health. The Armenian fermented dairy product, matsoun, is packaged not only in plastic and glass but also in clay pots. However, the impact of traditional packaging on the quality and safety of matsoun, especially heavy metal migration, remains under-researched. Objective: This study aimed to investigate the impact of ceramic packaging material on the quality and safety of matsoun during storage. Specifically, it compared the physicochemical properties (pH, titratable acidity), lactic acid bacteria (LAB) populations, and metal migration during storage. Methods: Six samples of matsoun were prepared and packaged in sterilized glass and ceramic containers. The samples were stored at 4 °C and analyzed on days 1, 7, and 15 of storage. The parameters measured included pH, titratable acidity, and LAB counts (coccus and bacillus). Heavy metal migration (Cd, Pb, Hg, As) was analyzed using atomic absorption spectroscopy. Results: The pH of samples packaged in ceramic and glass containers decreased over 15 days of storage, from 4.61 to 4.24 and 4.6 to 4.27, respectively. Titratable acidity increased in both groups, reaching 1.2 % lactic acid. A decrease in bacilli was observed in ceramic-packaged matsoun. The lead concentration remained constant at 0.0045 ppm across all samples. In ceramic containers, cadmium concentration increased from 0.0015 ppm to 0.0029 ppm by day 15. Conclusion: This study observed a decrease in pH, an increase in titratable acidity, and a relatively constant number of lactic acid bacteria indicating ongoing fermentation. The results showed nondetectable concentrations of arsenic (As) and mercury (Hg). The lead (Pb) concentration in all samples remained within the World Health Organization’s (WHO) allowed limit of 0.02 ppm. However, the concentration of cadmium (Cd) concentration in ceramic-packed increased, exceeding the WHO limit of 0.002 ppm. Further research is necessary to identify the sources of cadmium contamination. Keywords: food packaging, ceramic, matsou​​n​, heavy metal migration, food safety

Temporal variation, sources, fluxes, and risk assessment of heavy metals and arsenic in rainwater from Zhanjiang Bay, Northern South China Sea: Impact of typhoons Lion and Kompasu

This study investigates the impact of typhoon-induced rainfall on coastal pollution dynamics in Zhanjiang Bay during the 2021 wet season, focusing on typhoons Lion and Kompasu. Typhoon-induced rainfall (217 mm) contributed 23 % of the total wet season precipitation. Concentrations of Cu, Zn, Cd, and As in rainwater during typhoons were significantly diluted, showing decreases of 48 %, 48 %, 54 %, and 42 %, respectively. In contrast, Pb concentrations remained consistent (29.5 vs. 29.3 μg L−1), indicating that increased local emissions offset the dilution effect. The deposition fluxes of these elements during typhoons accounted for 12–21 % of total wet season deposits. A positive matrix factorization model identified six primary sources, highlighting a rise in coal combustion contributions during typhoons. Overall, while typhoons reduced risks for Cu, Cd, and As, risks for Zn and Pb increased upon deposition on Zhanjiang Bay, illustrating the complex impact of typhoon-induced rainfall on coastal pollution dynamics.

Health risk assessment of lead and cadmium exposure from food and snuff in Pakistani population

BackgroundSmokeless tobacco (SLT) is a tobacco-based product consumed without burning or smoking. Snuff, commonly known as naswar, is a widely used SLT product in Pakistan. This study is designed to investigate the concentrations of lead (Pb) and cadmium (Cd) in snuff and their associated health risks to consumers. MethodsBlood samples from snuff consumers and non-consumers were analyzed for Pb and Cd concentrations. Additionally, samples of drinking water and wheat flour were also analyzed for Pb and Cd. Health risk assessments were calculated using hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) for Pb and Cd. ResultsSnuff consumers had significantly higher blood-Pb and blood-Cd levels compared to non-consumers. Approximately 38.5 % of snuff consumers were found to exceed blood-Pb levels from the safe limits (10 µg dL⁻¹) of the World Health Organization (WHO), while 48.9 % of snuff consumers were found to exceed blood-Cd levels from the WHO safe range of 0.03–0.12 µg dL⁻¹. Snuff samples contained Pb and Cd concentrations ranging from 5.3 to 22.4 µg g⁻¹ and 0.5–2.2 µg g⁻¹, respectively. Drinking water and wheat flour samples were found within the safe limits for Pb and Cd concentration, suggesting snuff as the primary source of exposure. Health risk assessments indicated elevated HQ values, for Pb (38.9 %) and Cd (14.3 %) detected in snuff, surpassing the safe HQ threshold of 1. Concerning ILCR from snuff, values for Pb were within the acceptable range, but alarmingly 100 % of samples for Cd exceeded the safe limits of USEPA (1.0×10⁻⁴), indicating a significant cancer risk in snuff users. ConclusionThis study highlights the exceeded Pb and Cd concentrations in snuff as well as also reporting significant carcinogenic and non-carcinogenic health risks to consumers. These findings emphasized the urgent need for regulatory bodies to ensure the safety of snuff before selling in the market. Public Health Professionals should also initiate educational campaigns to raise awareness among consumers and manufacturers about various health risks associated with the snuff.

Pollution of Heavy Metals in Topsoil of Remote Mountainous Areas in Western Yunnan-Guizhou Plateau

Heavy metals from anthropogenic emissions have had a negative impact on the ecological environment in remote regions. A total of 69 topsoil samples were collected from 13 remote mountainous areas in the western Yunnan-Guizhou Plateau at altitudes of 2 563-4 037 m, and the concentrations of ten heavy metals in the samples were determined. Enrichment characteristics and pollution sources of heavy metals in topsoil were discussed by referencing the enrichment factor （EF）, positive matrix factorization （PMF）, and Pb isotopes. The results showed that the average concentrations of Al, Fe, Cu, V, and Zn in the topsoil were lower than the soil background values in Yunnan Province； the average concentrations of Ni and Pb were similar to the background values； and the average concentrations of Cd, Cr, and Hg were 1.8-3.6 times higher than the background values. The average EF values of Pb, Cr, and Ni were 3.8, 3.4, and 2.3, respectively, showing moderate enrichment according to the EF classification criteria； the average EF values of Cd and Hg were 15.2 and 10.0, reflecting significant enrichment； and the average EF values of the other metals ranged from 1.1 to 1.9, displaying none-weak enrichment. Combining the comparisons of heavy metal concentrations and ratios in topsoil and bedrock and the EF and PMF results, Al, Fe, V, Cr, Cu, Ni, and Zn in topsoil were considered primarily from detrital sources, and the spatial concentration variations of the metals should have been mainly regulated by the parent material. Cadmium, Hg, and Pb were obviously polluted by anthropogenic emissions, and the main sources were non-ferrous metal smelting and coal combustion. The areas with relatively high Cd, Hg, and Pb pollution were mainly distributed in the Jiaozi snow mountain, Bitahai watershed, Luoji Mountain, and Laojun Mountain areas. Anthropogenic emissions contributed 23.8% of the accumulation of heavy metals in the topsoil.

Characteristics, Source Apportionment, and Health Risk of Heavy Metals in the Soils of Peri-urban Shanghai Chongming Island.

Heavy metals resulting from human activities pose significant threats to human health and the soil ecosystem. In the current study, 917 soil samples from Chongming Island in Shanghai, China, were examined for eight heavy metals. The sources of contamination were identified by using a Positive Matrix Factorization (PMF) model. Meanwhile, spatial interpolation and Moran's I index were applied to validate the model in terms of spatial linkages. The results revealed that the average concentrations of As, Cd, Hg, Pb, Cr, Cu, Zn, and Ni in the soil were 8.87, 0.19, 0.06, 28.75, 76.01, 37.74, 88.93, and 30.33 mg kg-1, respectively. The PMF analysis proved that heavy metals in the soil of the study area are mainly influenced by traffic sources (Cr and Pb), industrial sources (Zn, Cd, and Cu), station sources (Hg), and natural sources (As and Ni), with contribution rates of 22.23, 26.25, 36.38, and 15.14%, respectively. The combination of Moran's index and the spatial analysis method not only verified the analytical results of the receptor model on the one hand but also served as a supplementary explanation for the sources of heavy metals in the soil. The health risk assessment indicated that noncarcinogenic values were below the threshold values. The total carcinogenic risk (R T) of different heavy metals has a descending order of Cr > As > Ni > Cd. The R T values of multiple heavy metals for children and adults were 5.28 × 10-04 and 4.10 × 10-05, respectively, which were close to the risk threshold. Therefore, attention should be paid to the health risks, especially for children's skin contact, which is the main exposure pathway.