Heavy Metal Concentrations Research Articles

Comparative Analysis of Concentrations of Heavy Metals in Surface Water of Nafada, Ashaka and Almakashi Corridors of River Gongola, Nigeria

A study on comparative analysis of heavy metals concentrations in surface water was carried out in three selected stations: Nafada, Ashaka and Almakashi along the corridors of River Gongola in Gombe state for a period of eighteen months. The water samples were collected in triplicate from the sampling stations. Water samples were collected using sampling bottles of 250ml dipped below the water surface for water collection. Zinc, lead, copper, cadmium and manganese were determined using Atomic Absorption Spectrophotometer. The result elucidates that most of the heavy metals were found to be within the recommended ranges as compared to standard limits. The result of concentrations of heavy metals in the surface water elucidates that there was a significant difference (P>0.05) among the months with respect to zinc and there was no significant difference in the concentration of lead (P<0.05). The concentrations follow the order (Zn >Cd>Cu>Mn>Pb). The higher concentration of heavy metals was found in Ashaka corridors with Zinc concentration ranging between 0.99±0.01 and 0.33±0.01, Cadmium 0.88±0.02 and 0.03±0.00, Cupper 0.58±0.02 and 0.14±0.02, Manganese 0.87±0.56 and 0.17±0.01, Lead 0.28±0.36 and 0.01±0.01. The wastewater from the cement effluent factory in Ashaka might have impacted negatively on the water chemistry by elevating the levels of some heavy metals. Therefore, more intensive treatment of the factory effluents before discharging into the River Gongola is recommended.

Ecological State of Environmental Facilities in the Zone of Influence of the Lipetsk Industrial Agglomeration

It has been found that the accumulation of heavy metals (HM) in environmental facilities of the Lipetsk industrial agglomeration varies significantly and may depend on the technological mode of the companies, the composition of aerosol fallout, soil properties, distance and direction from the emission plume, biological characteristics of plants and other factors. In the area where the Novolipetsk Iron and Steel Works (NLMK) is located, the excess levels of kerosene, gasoline and hydrocarbons in the atmospheric air were detected, as well as increased dust concentrations in the area of the Lipetsk Tractor Plant. At that, the concentrations of gaseous hazardous chemicals in the air of other areas of Lipetsk and agricultural lands at different distances and directions from NLMK did not exceed the established maximum values. The maximum content of HM was recorded in the upper layers of virgin undisturbed soils in the near zone of influence of industrial companies. It was noted that on arable soils the content of HM does not exceed the standard values, with the exception of a number of cases where the content of Fe, Cr, Ni in the grass stand exceeds the permissible level. It was concluded that the research carried out made it possible to identify the main patterns and factors influencing the pollution of environmental facilities, including components of agroecosystems.

A Comparative Study to Explore the Variability of Heavy Metal Concentration in the Teeth of Residents of Non-gated Versus Gated Societies.

Human populations face increasing exposure to heavy metals, which pose significant health risks. Dental tissues, such as dentin and enamel, provide a reliable biomarker for assessing long-term heavy metal exposure due to their stable nature. This study aims to explore the variability of heavy metal concentrations in the teeth dentine of residents living in gated versus non-gated societies near the Yamuna Riveraround the Jamia Millia Islamia, New Delhi, India. Sixty-nine participants were enrolled, 27 from gated societies and 42 from non-gated societies. Participants underwent elective dental extraction,following whichheavy metal concentrations were measured in extracted tooth dentine using atomic absorption spectrophotometry. Demographic data including age, gender, tooth types, and drinking water sources were recorded. Statistical analysis included Mann-Whitney's test, Spearman correlation heatmap, and principal component analysis (PCA). Residents of non-gated societies exhibited significantly (p< 0.005) higher mean concentrations of heavy metals compared to gated societies except for cadmium (p = 0.495). Subgroup analysis based on drinking water sources revealed significant (p<0.001) variations in heavy metal concentrations, suggesting the influence of water quality on environmental exposure. PCA provided insights into underlying trends and correlations among heavy metal variables. This study provides valuable insights into heavy metal contamination among residents living near the Yamuna River, highlighting disparities in exposure based on residential environment and drinking water sources. Participants from non-gated societies exhibited higher mean concentrations of heavy metals compared to those from gated societies, emphasizing the influence of socio-economic factors, urban infrastructure and environmental management practices on heavy metal accumulation. The study's findings underscore the need for targeted interventions to address heavy metal exposure across diverse population groups, improve water quality standards, and enhance access to safe drinking water.

Health risk assessment of heavy metals in Malay herbal medicine (MHM) consumed by pregnant and postpartum mothers

BackgroundMalay herbal medicine (MHM) is a popular medication and supplementation among Malaysian mothers during pregnancy and postpartum. It is expected to improve the baby’s health, increase breastmilk production, promote slimming and uterine involution, and improve the mother’s general health. Recent increases in reports of heavy metal contamination have raised safety concerns.ObjectiveThis pilot exploratory study employed a comparative cross-sectional design to investigate the types of MHM ingested during pregnancy and postpartum, their possible heavy metal contamination and associated health risks.MethodThis study involved 167 healthy postpartum Malay women.FindingsMHM consumption was significantly associated with the mother’s number of pregnancies and children (p < 0.05) as well as her pre-pregnancy weight (p < 0.05). Mothers who consume MHM were twice as likely (95% CI 1.077–3.963) to experience threatened abortion. Heavy metals were detected in the three most widely consumed MHM samples. The mean concentration of heavy metals in these samples were 47.44 ± 67.74 μg/kg for As, 25.34 ± 2.48 μg/kg for Cd, 3685.87 ± 5683.36 μg/kg for Cr and 194.33 ± 195.19 μg/kg for Pb. The calculated non-carcinogenic hazard health risks (HQ) and health index (HI) were less than one, suggesting no adverse health impacts under the exposure conditions studied.ConclusionWhile the HQ and HI values indicate no immediate health risks, the potential transfer from mother to foetus during pregnancy and from mother to infant during breastfeeding warrants further investigation. Additional studies are essential to confirm our findings and monitor the health of mothers and infants.

Hazardous waste alternative fuels to novel ecological energy: Combustion characteristics and effects on clinker's environmental safety

Due to their detrimental and persistent impacts on the environment, it is imperative to manage and dispose of hazardous wastes (HW) in a secure manner. This study investigates the combustion characteristics and environmental impacts of using HW as alternative fuels in clinker production. The HW categories analyzed include industrial hazardous waste (IHW), medical hazardous waste (MHW), and household hazardous waste (HHW). Specifically, IHW consists mainly of waste mineral oils, waste organic solvents, organic resin wastes, waste residues, and waste coatings. MHW primarily consists of medical plastic products. HHW mainly includes packaging from waste pharmaceuticals, waste pesticides, disinfectants, and waste paints. Compared to traditional pulverized coal, hazardous waste alternative fuel (HWAF) exhibits a lower fixed carbon content, with its heat generation primarily dependent on volatile substances, and a higher ash content, chemically similar to coal ash. The combustion process of HWAF involves three stages: moisture evaporation (0 °C–150 °C), volatile matter combustion (150°C–400 °C), and fixed carbon combustion (400 °C–550 °C). The primary emissions from this process include CO2, CO, trace amounts of SO2, NO2, H2O, and various complex organic compounds such as carboxylic acids, alcohols, ketones, and aldehydes. While HWAF ignites more readily than pulverized coal, it burns more slowly and less completely. The incorporation of combustion by-products into the cement clinker formulation does not interfere with the clinker's hydration processes or reactions. HWAF ensures a reduced heavy metal input rate in the firing system without significantly impacting the heavy metal content in the clinker. Mortar samples produced with this clinker meet the heavy metal leaching standards, affirming the environmental safety of the cement product. Increasing the proportion of HWAF results in a reduction in standard coal consumption and an increase in CO2 reduction, achieving a maximum coal saving of 3.67 kgce/t.cl and a CO2 emission reduction of 10.11 kg/t.cl. This study presents a clean production model for the co-processing of HWAF, effectively transforming waste into valuable resources by using hazardous waste materials as alternative fuels.

A local or a stranger? Comparison of autochthonous vs. allochthonous microalgae potential for bioremediation of coal mine drainage water

Coal mining endangers the environment by contaminating of soil, surface, and ground water with coal mine drainage water (CMW) polluted by heavy metals. Microalgal cultures, hyper-accumulators of heavy metals, represent a promising solution for CMW biotreatment. A bottleneck of this approach is the availability of microalgal strains that combine a large capacity for heavy metal biocapture with a high resilience to their toxic effects. Biotopes contaminated with heavy metals are frequently inhabited by microalgae evolved to be resilient to heavy metal toxicity. Therefore, the autochthonous (locally isolated) microalgal strains are a priori considered to be superior for biotreatment of heavy metal-polluted waste streams. Still, strains from biocollections combine a high pollutant resilience with other biotechnologically important traits such as high productivity, high CO2 sequestration rate etc. Moreover, the strains available “off-the-shelf” would enable rapid development of bioprocesses. Here, we compared the efficiency of CMW biotreatment with autochthonous (isolated from the coal mine drainage sump) and allochthonous microalgae (from a geographically distant phosphate-polluted site). Both autochthonous strains and allochthonous strains turned to be interchangeable under our experimental conditions. Still, the autochthonous strains showed a higher capacity for sequestration of iron, zinc, and manganese, the specific pollutants of the studied CMW. It can be important when the duration of unattended exploitation of the CMW treatment facility is a priority or spikes of the heavy metal concentration in CMW are expected. Therefore, the “off-the-shelf” strains can be a plausible solution for rapid development of CMW treatment technologies from scratch (although screening for acute toxicity of CMW is imperative). On the other hand, locally isolated strains can offer distinct advantages and should be always considered if sufficient time and other resources are available for the development of microalgae-based process for CMW treatment.

Microplastic and heavy metal contamination in sediments of the high-altitude Nundkol Lake of northwestern Himalayas-Kashmir

This study investigates heavy metal and microplastic contamination in the sediment of Nundkol Lake, a high-altitude glacial lake in the northwestern Himalayas. Sediment analysis revealed heavy metal concentrations significantly exceeding background levels, with average concentrations of cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn), and chromium (Cr) recorded at 40.991 ppm, 54.434 ppm, 87,843.59 ppm, 1544.566 ppm, 83.288 ppm, 16.312 ppm, 104.571 ppm, and 106.514 ppm, respectively. Notably, the highest levels of Cu, Fe, Mn, and Pb were observed in sample GL2, indicating potential local geochemical anomalies. The trace elements were quantified using a Graphite Furnace - Atomic Absorption Spectrophotometer (Perkin Elmer-PinAAcle 900AA) for high precision.Microplastic analysis revealed an average abundance of 76±12.08 items/kg dry weight, predominantly fibers. The microplastics were mostly red (55.26 %), blue (36.84 %), orange (5.26 %), and green (2.63 %). Raman spectroscopy identified Polyamides (PA) as the predominant type (86.5 %), with the remainder being Polyethylene (PE) and Polypropylene (PP). The results suggest tourism, fishing, and trekking activities as major contributors to microplastic presence. This study uniquely combines the assessment of heavy metal and microplastic contamination in a high-altitude lake, providing a comprehensive view of pollutant dynamics. The findings highlight the need for tailored mitigation strategies and comprehensive monitoring programs to protect this fragile region. Applications include informing environmental policy, guiding pollution mitigation efforts, and promoting sustainable tourism practices. This study offers valuable insights into the environmental health of high-altitude lakes and underscores the need for efforts to mitigate anthropogenic impacts.

Methane oxidation coupling with heavy metal and microplastic transformations for biochar-mediated landfill cover soil

The impact of co-occurring heavy metal (HM) and microplastic (MP) pollution on methane (CH4) oxidation by methanotrophs (MOB) in landfill cover soil (LCS) and the role of biochar in mediating these collaborative transformations remains unclear. This study conducted batch-scale experiments using LCS treated with individual or combined HMs and MPs, with or without biochar amendment. Differentiation in methanotrophic activities, HM transformations, MP aging, soil properties, microbial communities, and functional genes across the groups were analyzed. Biochar proved essential in sustaining efficient CH4 oxidation under HM and MP stress, mainly by diversifying MOB, and enhancing polysaccharide secretion to mitigate environmental stress. While low levels of HMs slightly inhibited CH4 oxidation, high HM concentration enhanced methanotrophic activities by promoting electron transfer process. MPs consistently stimulated CH4 oxidation, exerting a stronger influence than HMs. Notably, the simultaneous presence of low levels of HMs and MPs synergistically boosted CH4 oxidation, linked to distinct microbial evolution and adaptation. Methanotrophic activities were demonstrated to affect the fate of HMs and MPs. Complete passivation of Cu was readily achieved, whereas Zn stabilization was negatively influenced by biochar and MPs. The aging of MPs was also partially suppressed by biochar and HM adsorption.

The Continued Presence of Antibiotic-resistant Bacteria and Heavy Metals at one of the World’s Most Important Green Turtles’ Nesting Location, Ras al-Jinz Reserve, Oman

Environmental contamination of marine habitats is a global concern, especially in areas that are crucial for endangered species’ life cycles. To gain a comprehensive understanding of environmental contamination, analyzing various biotic and abiotic components of ecosystems is necessary. Situated in the Arabian Peninsula, Ras al-Jinz Reserve serves as an invaluable nesting site for green sea turtles (Chelonia mydas). There, the prevalence of antibiotic-resistant microbial strains and heavy metals was assessed by collecting samples from diverse components of this ecosystem, including sand from turtle nests, dead turtle hatchlings, fresh turtle eggs, oviductal fluids from nestling turtles, turtle carapace smears, live crabs, and seawater. Microbial fauna was identified using a MALDI-TOF Biotyper. The concentration of heavy metals was measured by an inductively-coupled plasma mass spectrometry. Among the isolated bacterial strains, 70 heterotrophic species belonging to eleven genera were identified, with over 46% of isolates belonging to the Pseudomonas species. More than 85% of isolates displayed antibiotic resistance but had negligible resistance to chloride. Of the 23 heavy metals assessed, Titanium and, in lesser measure Vanadium, were found in the highest concentrations, reaching up to 12 µg g-1. While such concentrations might not be immediately alarming, they are significant enough to warrant attention due to the potential health and environmental impacts. These results obtained over a decade after the last monitoring in the Reserve provide compelling evidence of the persistent presence of antibiotic-resistant bacteria. Additionally, the study confirms the prevalence of heavy metals, the sources of which remain unknown but are likely from anthropogenic sources. It is crucial to implement measures that mitigate sea turtles’ exposure to contaminants in Ras al-Jinz Reserve. Regular monitoring efforts are required to assess the emergence of discernible contamination trends in this critically important area. Keywords: Chelonian conservation; Environmental contamination assessment; Microbial contamination; Biological reserve; Coastal pollution.

Quantification of selected heavy metals through inductively coupled plasma-optical emission spectrometry in containers of yogurts used in Erbil City, Krg, Iraq

Heavy metals are recently introduced in the manufacturing of various household utensils. The objective of this study was to investigate different heavy metals contents in the composition of yogurts containers collected from the markets of Erbil City. The collected containers were aluminum containers and plastic containers with several colors. An inductively coupled plasma optical emission spectrometer was used to analyse the contents of nine heavy metals including cadmium, cobalt, chromium, copper, iron, lead, manganese, nickel, and zinc. The level of total detected metal load found in the analyzed containers. The recorded level for total detected metal load in the overall aluminum containers sample was very high and approximately 27 times more than that level in the overall plastic containers sample. Lead and cadmium were known as toxic heavy metals and detected with a high amount in the aluminum containers composition. The total contamination in the aluminum containers composition was noticeably exceeded the permissible world limits for heavy metals in packaging materials. Results obtained clarified that the white color of plastic containers is more preferable and safer than the dark or other multi-color plastic containers items in terms of heavy metals. KEY WORDS: Aluminum and plastic container, Heavy metal, ICP-OES, Yogurt Bull. Chem. Soc. Ethiop. 2024, 38(6), 1509-1519. DOI: https://dx.doi.org/10.4314/bcse.v38i6.1

Bangladeş'in Chattogram ve Cox's Bazar bölgesindeki çamur yengeci (Scylla serrata) ve ortam çamurundaki ağır metal konsantrasyonu

Heavy metal levels have increased due to increased industrialization, which has a negative impact on crab, an essential source of protein. This study aimed to measure the level of certain heavy metals (Pb, Cd, and Hg) in edible tissue from mud crab (Scylla serrata) and related soil collected from Chattogram and Cox's Bazar in Bangladesh. The concentration of heavy metals in mud crab and the soil were determined using an Atomic Absorption Spectrophotometer (AAS) (Model ICE 3300). While the mean values of heavy metals in crab tissue samples from Chattogram were 0.06 mg/kg for Cd and 0.45 mg/kg for Pb, in the related soil samples these values were determined as 0.52 mg/kg for Cd and 7.24 mg/kg for Pb. In Cox's Bazar, the mean Pb content was 4.1 mg/kg in related soil, but the levels of Cd and Hg were below the detection limit. In S. serrata tissues, all heavy metal concentrations were below the detection limit. The heavy metal values obtained in the study were compared with the Food and Agriculture Organization (FAO), World Health Organization (WHO), European Union (EU) and Food and Drug Administration (FDA). Results concluded that metal concentrations were within permissible limits and did not pose an immediate risk to public health or human consumption. Specifically, the measured concentration levels are considered poor when compared to national and international requirements.

Influence of municipal waste treated sludge on the quality attributes of African marigold (Tagetes erecta)

Using treated sludge to amend soil in agriculture presents opportunities and challenges, particularly concerning the augmentation of heavy metals in cultivated plants. This research looks into how applying treated sludge affects the buildup of heavy metals in African marigold (Tagetes erecta), a popular ornamental plant that could potentially help with phytoremediation. Several treatment combinations were imposed, out of which treated sludge at 2.5 t/ha showed promising results. The effect of incorporating treated sludge was found to be better in terms of using conventional manures like Farm Yard Manure and Vermicompost in quantitative terms. The sludge processed at the treatment plant underwent strict treatment procedures, resulting in odourless material that can be used as an organic amendment with nutrients. Heavy metal concentrations in plant tissues were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICPMS) to assess the uptake and accumulation of heavy metals by African marigolds. Results indicated that treated sludge application did not significantly influence the accumulation and bioavailability of heavy metals in African marigolds. The treated sludge helped plants grow better and absorb nutrients; it did not cause higher levels of harmful heavy metals like cadmium and lead in the plants. The levels of heavy metals found were lower than what is considered unsafe for plants. In addition, treated sludge can serve as a soil conditioner to enhance the physicochemical properties of the soil.

Hydrothermal carbonization of coking sludge: Migration behavior of heavy metals and magnetic separation performance of hydrochar

This study comprehensively investigated the migration behavior and environmental risk of heavy metals (HMs) during the hydrothermal carbonization (HTC) of coking sludge (CS). The results indicated that over 90 % of HMs accumulated in the coking sludge hydrochar (CHC). The decomposition and loss of organic matter led to an increased concentration of HMs with rising temperatures. However, HTC also facilitated the transformation of HMs from bioavailable fractions to more stable fractions. Higher hydrothermal temperatures positively influenced the control of HMs' environmental risks. Ecological risk assessments revealed that the Potential Ecological Risk Index (RI) values of HMs in CHC decreased from 631.15 to 134.23, reaching considerate risk levels. Risk assessment codes indicated that, except for Mn, other HMs were reduced to no risk or low risk after hydrothermal treatment. Furthermore, the magnetic separation performance of CHC was explored, and its practical value was validated using a semi-continuous adsorption-separation device. The results showed that CHC achieved removal rates of 80.41–87.15 % for Congo red (CR) and tetracycline (TC), maintaining stability in various complex water environments. The CHC was rapidly separated after adsorption with a simple magnetic field, achieving a separation and recovery rate of over 80 %. These findings provided theoretical support for the stabilization of HMs in CS and the resource utilization of hydrochar in water treatment applications.

Detection and assessment of heavy metals concentration in wheat leaves collected from the vicinity of Sahiwal coal power plant, Pakistan, employing a modern data analysis approach

ABSTRACT Heavy metal pollution in food crops has become a global issue, especially in staple crops like wheat and rice. Electricity production utilising coal, ignites this issue in crops grown in the surrounding areas of coal power plants. Keeping this view in mind, the concentration of six heavy metals (HMs) Calcium (Ca), Cadmium (Cd), Chromium (Cr), Cobalt (Co), Lead (Pb) and Magnesium (Mg) in wheat leaves have been assessed in this study. Fifty samples of wheat leaves have been collected from the surrounding areas of the coal power plant in Sahiwal. The samples were prepared using the wet digestion method (WDM). Finally, these samples have been sent for analysis via atomic absorption spectroscopy (AAS). The limit of detection (LOD) and limit of Quantification (LOQ) of AAS were calculated with the help of blank samples. The concentration of Ca, Cd, Cr, Co, Pb and Mg in wheat leaves were 1.0187 ± 0.549 mg/kg, 0.00484 ± 0.00403 mg/kg 00,416 ± 0.00334 mg/kg, 0.0534 ± 0.0351 mg/kg, 0.035 ± 0.018 mg/kg, 0.464 ± 0.200 mg/kg respectively. The concentration of all understudy metals was below the Food and Agriculture Organization/World Health Organization (WHO/FAO) standards except for Co, in one sample. However, the concentration of heavy metals may increase, which may have profound repercussions. Therefore, preventive measures should be taken in this regard. The neutrosophic approach has been utilised to examine the variation of the heavy metals content in wheat leaves. This study provides a solid scientific foundation for future appropriate actions and management of heavy metals contamination in food crops near coal-fired power stations.

Comparative Analysis of Heavy Metal Content in Impacted Third Molars from Industrial and Non-Industrial Areas and Its Effect on the Isolation, Culture, and Proliferation of Dental Stem Cells (DSCs).

Background: This study investigates the impact of environmental pollution on the quality and viability of dental stem cells (DSCs) from impacted third molars. By comparing DSCs from patients in industrial areas with high air pollution and those from non-industrial regions, the research assesses the adverse effects of heavy metals on stem cell proliferation. Methods: Impacted lower third molars were collected from 28 patients-10 from industrial and 18 from non-industrial areas. Patients were divided into two age groups: 18-27 years and 28-38 years old. Dental pulp was extracted under sterile conditions, and DSCs were isolated and cultured. Heavy metal concentrations in dental tissues were measured using atomic absorption/emission spectrometry. Results: The study found significantly higher concentrations of copper and lead in the dental tissues of patients in industrial areas. Cell viability was lower in samples from these areas, with a statistically significant difference in average doubling time and the number of cells obtained after the first passage. There was no significant impact of gender on heavy metal content, except for higher iron levels in men. Conclusions: Exposure to industrial pollutants negatively affects the viability and proliferation of DSCs, but there are no differences in differentiation in the osteogenic medium regarding cell mineralization. These studies highlight the importance of environmental factors for oral health, suggesting that residents of polluted areas may face greater difficulties in dental and regenerative treatments. Further research is needed to develop strategies to mitigate the effects and improve clinical outcomes for affected populations.

Toxicity assessment of heavy metals translocation in maize grown in the Ganges delta floodplain soils around the Payra power plant in Bangladesh

As a cereal crop, maize ranked third place after wheat and rice in terms of land area coverage for its cultivation, and in Bangladesh, it ranked second place after rice in its production. As the substitution of wheat products, maize has been used widely in baking for human consumption and animal fodder. However, maize grown in this soil around the coal-burning power plant may cause heavy metals uptake that poses a risk to humans. The study was conducted at the maize fields in the Ganges delta floodplain soils of Bangladesh to know the concentration of eight heavy metals (Ni, Cr, Cd, Mn, As, Cu, Zn, and Pb) in soil and maize samples using an inductively coupled plasma mass spectrometer (ICP-MS) and to estimate the risk of heavy metals in maize grains. Mean concentrations of heavy metals (mg/kg) in soil were in decreasing order of Zn (10.12) > Cu (10.02) > Mn (5.48) > Ni (4.95) > Cr (3.72) > As (0.51) > Pb (0.27) > Cd (0.23). The plant tissues showed the descending order of heavy metal concentration as roots > grains > stems > leaves. BCF values for As, Cd, Pb, and Mn in roots were higher than 1.0, indicating considerable accumulation of these elements in maize via roots. Total hazard quotient (ƩTHQ) of heavy metals through maize grain consumption was 3.7E+00 and 3.9E+00 for adults and children, respectively, indicating non-cancer risk to the consumers. Anthropogenic influences contributed to the heavy metals enrichment in the Ganges delta floodplain soils around the thermal plant, and potential risks (non-carcinogenic and carcinogenic) were observed due to the consumption of maize grain cultivated in the study area.

Heavy metal contamination of surface soils by anthropogenic activities: concomitant ecological and health risk assessment

ABSTRACT The heavy metals in the soil are a condemnatory environmental threat as they expand their toxic effects on the environment as well as human health. The present study is intended to analyse the concentrations of heavy metals (K, Ca, Mg, Ti, Fe, Co, Cu, As, Zn, Rb, Sr, Zr, Pb, and Th) in soil samples congregating near a urea fertiliser factory utilising Energy Dispersive X-ray Fluorescence (EDXRF) technique and evaluate their distinctiveness, emergence and subjection to human. Mean value of Mg, K, Ca, Ti, Fe, Co, Cu, Zn, As, Rb, Sr, Zr, Pb and Th in the sampling area was found 14712, 11828, 8607, 4378, 47358, 10.93, 17.04, 151.57, 8.65, 191.08, 191.42, 263.64, 88.69 and 17.55 mg kg−1 respectively. Geo-accumulation index (Igeo), enrichment factor (EF) and contamination factor (CF) revealed the sampling sites were practically uncontaminated to moderately contaminated, and minimum to moderately enriched by the elements. Besides, a low level of risk was evaluated from the estimated value of the Ecological risk index (RI). Principal Component Analysis (PCA), Correlation Analysis (CA) and correlation coefficient indicated that the geological and the anthropogenic origins have boosted the elemental concentration in the soil samples. Regardless of age, the Hazard quotient (HQ) and Hazard index (HI) values in all three exposure pathways (HQ/HI < 1) and total lifetime carcinogenic risk (TCR < 1E–06) from the complete exposure path stipulated negligible risk and could cause no obvious health hazards on the surrounding populations. However, children manifested potential receptors of heavy metals compared to adults and were more susceptible to carcinogenic and non-carcinogenic risks.

Assessment of heavy metal levels in cow's milk and associated health risks in the vicinity of the MIDROC Laga Dambi gold mine in Ethiopia

IntroductionThe possible health effects of consuming milk contaminated with heavy metals have been the subject of considerable concern worldwide. ObjectiveThe aim of this study was to determine the level of heavy metals in cow's milk in the vicinity of MIDROC Laga Dambi gold mine and to assess their possible health risks for consumers. MethodsNine composite samples were formed by aggregating 243 milk samples obtained in triplicates from 81 domestic milk-producing households. Inductively coupled plasma-optical emission spectroscopy was used to measure the amount of heavy metals after samples digestion under optimal conditions. ResultsThe heavy metals concentrations obtained were 13.913˗7.843, 9.505˗3.589, 5.972˗3.147, 2.288˗1.851, 0.403˗0.143, 0.436˗0.128, 0.26˗0.153, 0.143˗0.048, 0.160˗ND (not detected), and 0.140˗ND mgkg−1for Fe, Zn, Pb, Mn, Hg, Cr, Cd, As, Ni, and Co, respectively. Of the heavy metals identified, the levels of Pb, As, Cd, and Hg exceeded the recommended value. Based on the estimated daily intake (EDI), the total health quotient (THQ) is higher than unity even for Pb alone. It has been found that the consumption of cow milk increases the health index (HI) by 2.972. Ninety five percent of the HI in the study area was explained by the toxic heavy metals (Pb, Cd, As, and Hg) in the cow milk, which were found to be beyond the safe limit. ConclusionThis demonstrates that there is a health risk to the population who consume cow’s milk sourced from the vicinity of MIDROC Laga Dambi gold mine. To safeguard the public’s health, we advised strict monitoring and legislative control for the safety of cow’s milk originating from study area.

A correlation study of road dust pollutants, tire wear particles, air quality, and traffic conditions in the Seoul (South Korea)

The interdependence of traffic dynamics and air quality on the concentrations of tire wear particles (TWP), heavy metals, and carbon black (CB) in road dust collected from 15 locations in Seoul, South Korea, was assessed. Pearson correlation, principal component analysis, and network analysis were employed to evaluate the correlations among traffic volume, vehicle speed, air quality parameters (PM10, PM2.5, NOx, and CO), and the concentrations of TWP (5934 to 16,253 mg/kg, average 9581 ± 4086 mg/kg), CB (371–22,287 mg/kg, average 4291 ± 6096 mg/kg), and heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb) in road dust. The enrichment factors for heavy metals and the pollution index of TWP and CB were also calculated to evaluate the contribution of vehicle-derived particulate substances to road dust contamination. It was found that Cluster B, characterized by traffic-related variables such as traffic volume, vehicle speed, and heavy metals (Zn, Cd, and Pb), was significantly correlated with these pollutants, with correlation coefficients reaching up to 0.933. TWP was identified as a significant mediator in the increase of Zn, Pb, and Cd concentrations linked to traffic activities, contributing to pollution levels that were 2–16 times higher than the geochemical background. The presence of TWP and CB in road dust was identified as an indicator of contamination from traffic-related activities, highlighting the importance of Zn, Pb, and Cd as emerging pollutants that require targeted management strategies.

Efficient recovery and utilization of phosphorus from sewage sludge via alkalinous fenton-like oxidation with pyrolysis-modified red mud: Full resource utilization attempt

Red mud (RM) and sewage sludge (SS) are growing massive industrial wastes, and recycling utilization is considered a suitable disposal method. In this study, a novel Fenton-like catalyst was synthesized through co-pyrolysis with RM and SS with high alkaline endurance, presenting a sustainable full resource utilization of the SS. The advanced oxidation process effectively breaks down the SS structure to release phosphorus(P) for struvite recovery. The residual SS can be repurposed as fuel following direct flocculation and dehydration. There is no need for complex pH adjustments throughout. XRD pattern revealed zero valent iron (ZVI, Fe0) as the primary catalyst phase. Experimental findings demonstrated that H2O2 efficiently disrupts bacterial structures, leading to a significant reduction in bound extracellular polymer (TB-EPS) in the SS. It was observed that the release rate of P reached nearly 100% after 60 min of reaction. The purity of recycled struvite reaches 94.9%, and the heavy metal content meets national standards. Planting experiments indicated that recycled struvite exhibited superior fertility compared to commercial fertilizers. The proposed sustainable resource production and recycling process of SS strongly supports the construction of a "city without waste".