Heavy Metal Contamination Research Articles

Analyzing Soil Pollution by Image Processing and Machine Learning at Contaminated Agricultural Field

Due to the fast advancement of big data, applying Machine Learning (ML) techniques to detect Soil Pollution (SP) at Potentially Contaminated Sites (PCS) across many sectors and regional sizes has emerged as a prominent research focus. The challenges in acquiring essential indices of SP sources and routes result in present methodologies exhibiting low predictive accuracy and an inadequate scientific foundation. This study gathered environmental data concerning heavy metal and organic contamination from 200 PCS across six representative sectors. Twenty-one indices derived from fundamental data, potential SP from products and materials, SP efficacy, and the migrating capability of SP were employed to build the SP detection index method. The research integrated the score into the new characteristic group, including 11 indicators using consolidation computation. The newly selected feature subset was utilized for training ML designs, including Random Forests (RF), Support Vector Machines (SVM), and Multilayer Perceptrons (MLP), and evaluated to ascertain its impact on SP recognition methods. The study findings indicated that the four newly developed indices by feature fusion exhibit an association with SP comparable to that of the original index. The component analysis suggests that several indices related to fundamental information, contamination potential from products and raw materials, and SP prevention levels significantly influence SP to varying extents. The index of the migratory capability of soil contaminants has minimal influence on the classification job of SP detection inside PCS. This research introduces a novel technological approach for identifying SP via big data and ML techniques while offering an overview and scientific foundation for PCS's environmental administration and SP mitigation.

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

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

Silica/klucel nanocomposite as promising durable adsorbent for lead removal from industrial effluents

The removal of heavy metals, such as lead, from industrial wastewater is imperative due to their detrimental effects on both human health and the environment. This study delves into investigating the feasibility of employing a novel adsorbent, specifically a silica/klucel nanocomposite, for effectively extract lead from industrial effluents. The synthesis of this nanocomposite involved a simple and cost-effective method, combining silica nanoparticles with klucel. XRD, FTIR, E-SEM, Raman, and N2 gas adsorption at − 196 °C tools were employed to prospect the formation of silica/klucel nanocomposite. Outstandingly, treating 50 ml of 50 mg/l of lead with 10 mg of adsorbent exhibited rapid removal, which reached a maximum (95%) at 60 min contact time. The resulting composite demonstrated remarkable adsorption capabilities, primarily attributed to two factors: the expansive surface area of silica nanoparticles 139.1 m2/g and the porous structure provided by klucel. Through batch adsorption experiments, the nanocomposite’s proficiency in removing lead ions from aqueous solutions became evident. The kinetics of the adsorption process were found to adhere closely to a pseudo-second-order model, hinting at chemical adsorption as the rate-determining step. Langmuir isotherm model revealed that lead ions tend to form a monolayer on the surface of the nanocomposite and the maximum adsorption capacity (qm) was 63.938 mg/g. Additionally, the nanocomposite, exhibited notable stability and could be reused multiple times, where 65% removal efficiency was announced until the 7th cycle without significant degradation in performance. In summary, the silica/klucel nanocomposite emerges as a promising and eco-friendly adsorbent for removing lead from industrial effluents. Its efficient performance and sustainability offer a compelling solution to combat heavy metal contamination, thereby contributing to environmental preservation and human well-being.

Multi-metal resistance and antibiotic susceptibility of biofilm forming bacteria isolated from Kuzhikandam Creek in Kochi, southwest part of India

The purpose of this work was to characterize and identify the bacteria isolated from highly polluted locations that could potentially be able to withstand extremely toxic heavy metals. The study area selected for bacterial isolation from sediment samples was Kuzhikandam Creek, a tributary of the Periyar River and one of the world’s most hazardous hotspots, located in Kochi’s Eloor industrial region. Heavy metal analysis of chromium, copper, and lead in sediment samples was performed, and the results showed that the concentrations were greater than permissible limits. Several metal-resistant bacteria were isolated from sediments, which, upon further screening in solid media at different concentrations of chromium, copper, and lead, found three highly resistant species (S1B1, S2B2, and S3B3), one from each site. The phenotypic and biochemical characterization of these bacteria was examined using standard procedures. The ability of these species to generate biofilm was examined using methods like the crystal violet assay (qualitative assessment) and also using the scanning electron microscope. The antibiotic susceptibility of these species was tested with six different antibiotics, which are used in various disease treatments. These isolates, sequenced using the 16S rRNA Sanger dideoxy method, have been identified as Staphylococcus arlettae, Bacillus paramycoides, and Cellulosimicrobium funkei.

Spatial pattern, source apportionment, and source-oriented health risk quantifying of heavy metals in farmland soils of southern China.

The contamination of heavy metal has permeated many parts of China, especially in densely populated and industrialized southern China. This study focused on the degree of pollution in farmland soil heavy metals (HMs), and its spatial distribution characteristics and source apportionment. Meanwhile, we conducted an evaluation of the health risks attributed to soil HMs and analyzed the factors that impact them. We found that the distribution of five heavy metals is mainly concentrated in the east-central and southern parts of the study area. Specifically, Cd and Hg have high levels of pollution and present potential ecological risks. The pollution sources of five HMs were analyzed utilizing positive matrix factorization. The results revealed that the contribution of different sources keeps the following order: natural source (42.42%), agricultural activities (29.93%), industrial pollution source (20.49%), and atmospheric deposition pollution (7.16%). The non-carcinogenic risks to residents were acceptable, whereas the carcinogenic risks were relatively high. Children and the elderly are more vulnerable to the negative effects of Cr, As. Using structural equation modeling, we found soil property is a vital factor affecting soil contamination, with the soil organic matter and cation exchange capacity having a relatively greater impact on heavy metals pollution. Our study provides some data reference and guidance for soil ecological protection and restoration.

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

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

Electrochemical Biosensor for Detecting both Pb2+ and Hg2+ in Human Blood

Many studies have demonstrated that lead ion ( Pb2+ ) and mercury ion ( Hg2+ ) are harmful to human health. Lead was found to accumulate in the kidney, leading to oxidative stress, apoptosis, and inflammation in the nephrons, and possess marked testicular toxicity. Mercury is well-known to produce nephrotoxicity, inflammatory responses and induce oxidative stress and apoptosis. These heavy metals can enter the human body in various ways, such as through skin or inhalation routes, or contaminated drinking water and food. But heavy metal poisoning is not easy to diagnose because existing detecting measures has many disadvantages cause them can’t widely spread. So, seeking an easy way to detect them in human blood to discover lead or mercury poisoning is an unmet need. This paper develops a new reusable biosensor for detecting both Pb2+ and Hg2+ in human blood. This work is based on the reaction between guanine and Pb2+ form of G-quadruplex and Hg2+ connect two thymines together cause the variation of electrochemical signal. The signal is magnified by methylene blue-gold nanoparticles (MB-AuNP) to increase the limit of detection Although the reuse part of sensor is still in theory, but this approach can make the cost of sensor low and create the feasibility of recycle. Overall, providing a new idea to make contributions to the prevention of heavy metal poisoning is the reason why this study is conducted.

The Role of Organic Amendments and Their Impact on Soil Restoration: A Review

Soil organic matter (SOM) plays a pivotal role in maintaining soil health by enhancing its physical, chemical, and biological properties. It improves soil structure, water retention, nutrient availability, and microbial activity, contributing significantly to sustainable agriculture. Organic amendments, including animal manure, compost, biosolids, crop residues, and various organic by-products, are widely used to restore degraded soils by increasing SOM content. These amendments not only supply essential nutrients but also promote biological aggregation, suppress soil-borne pathogens, and improve soil's resistance to environmental stressors such as drought and heavy metal toxicity. The positive impacts of organic amendments on soil properties are well-documented, with key benefits including increased soil organic carbon (SOC), improved nutrient cycling, enhanced microbial diversity, and greater water-holding capacity. Organic materials such as compost and animal manure have been shown to significantly improve soil fertility and restore degraded soils. The application of green manure and crop residues also boosts soil biodiversity, enhances rhizospheric processes, and supports overall ecosystem resilience. This paper emphasizes the importance of adopting holistic soil management practices that include organic amendments, conservation tillage, and sustainable cropping systems to address soil degradation. By focusing on replenishing SOM, improving nutrient availability, and increasing soil biodiversity, these practices can contribute to the long-term sustainability of agricultural systems and environmental health. The restoration of soil organic matter is essential for enhancing soil quality and mitigating degradation, ultimately ensuring food security and ecosystem stability for future generations.

Evaluation of heavy metal contamination: an analogy between conventional techniques and paper microfluidics as the futuristic probe for diverse environmental matrices

Evaluation of heavy metal contamination: an analogy between conventional techniques and paper microfluidics as the futuristic probe for diverse environmental matrices

Bioremediation of metal cyanide complexes from electroplating wastewater for long-term application using Agrobacterium tumefaciens SUTS 1 and Pseudomonas monteilii SUTS 2.

The purpose of this study was to investigate the optimum conditions, including aerobic and anoxic conditions, for operating a long-term bioreactor system to decrease the toxicity of industrial electroplating wastewater effluents containing metal cyanide using Agrobacterium tumefaciens SUTS 1 and Pseudomonas monteilii SUTS 2. The initial results revealed that bacteria performed better under aerobic conditions than under anoxic conditions. An aerobic bioreactor system was subsequently set up in a long-term study lasting 30days under optimum operating conditions. Both mixed-culture bacteria and indigenous bacteria promoted the high-efficiency treatment of cyanide and metals in the first 7days of the study. When the system had high removal rates, cyanide removal was greater than that of zinc, copper, nickel, and chromium (CN- > Zn > Cu > Ni > Cr), with removal efficiencies of 96.67%, 93.93%, 74.17%, 63.43%, and 44.65%, respectively, with residual concentrations of 0.15 ± 0.01, 0.24 ± 0.005, 0.03 ± 0.002, 18.41 ± 0.06 and 14.26 ± 0.15mg/L, respectively. The cell concentration in the bioreactor increased to approximately 107CFU/mL over 30days from initial cell concentrations of 6.15 × 105 CFU/mL and 1.05 × 103CFU/mL for the mixed culture and indigenous inoculation, respectively. These results implied that the bacteria were resistant to heavy metal toxicity. The addition of an appropriate carbon source with sufficient aeration to a bioreactor resulted in increased cyanide degradation.

Unraveling the Role of Contaminants Reshaping the Microflora in Zea mays Seeds from Heavy Metal–Contaminated and Pristine Environment

Heavy metal (HM) contaminants are the emerging driving force for reshaping the microflora of plants by eradicating the non-tolerance and non-resistant microbes via their lethal effects. Seeds served as a prime source of ancestral microbial diversity hereditary transfer from generation to generation. However, the problem arises when they got exposed to metal contamination, does metal pollutant disrupt the delicate balance of microbial communities within seeds and lead to shifts in their microflora across generations. In this study, the endophytic community within Zea mays seeds was compared across three distinct regions in Yunnan province, China: a HM-contaminated site Ayika (AK), less-contaminated site Sanduoduo (SD), and a non-contaminated Site Dali (DL). High-throughput sequencing techniques were employed to analyze the microbial communities. A total of 492,177 high-quality reads for bacterial communities and 1,001,229 optimized sequences for fungal communities were obtained. These sequences were assigned to 502 and 239 operational taxonomic units (OTUs) for bacteria and fungi, respectively. A higher diversity was recorded in AK samples than in SD and DL. Microbial community structure analysis showed higher diversity and significant fluctuation in specific taxa abundance in the metal-polluted samples exhibiting higher response of microbial flora to HM. In AK samples, bacterial genera such as Gordonia and Burkholderia-Caballeronia-Paraburkholderia were dominant, while in SD Pseudomonas and Streptomyces were dominant. Among the fungal taxa, Fusarium, Saccharomycopsis, and Lecanicillium were prevalent in HM-contaminated sites. Our finding revealed the influential effect of HM contaminants on reshaping the seed microbiome of the Zea mays, showing both the resilience of certain important microbial taxa as well the shifts in the diversity in the contaminated and pristine conditions. The knowledge will benefit to develop effective soil remediation, reclamation, and crop management techniques, and eventually assisting in the extenuation of metal pollution's adverse effects on plant health and agricultural productivity.

Assessment of Metal Pollution in Sediments and Their Bioaccumulation in Phragmites australis from Shoor River, Iran

ABSTRACT Heavy metal contamination is a serious global issue that threatens both environmental and human health. This study investigated the levels of 12 heavy metals in sediments, roots, stems, and leaves of Phragmites australis (common reed) from a river in Iran, using an inductively coupled plasma optical emission spectrometer (ICP-OES). The sediment metal concentration order was: Aluminum (Al) > Iron (Fe) > Manganese (Mn) > Zinc (Zn) > Magnesium (Mg) > Nickel (Ni) > Chromium (Cr) > Lead (Pb) > Copper (Cu) > Arsenic (As) > Vanadium (V) with Cadmium (Cd) below detection limit. Concentrations of As, Ni, Pb, and Zn in the sediments exceeded background values. According to sediment quality guidelines (SQGs), metal concentrations were between the threshold effect level (TEL) and the probable effect level (PEL), remaining below the severe effect level (SEL), except for Ni. Average metal concentrations in plant tissues were lower than in sediment samples, with roots showing higher levels of Cd, V, Cu, Pb, Zn, As, Al, Mg, and Fe than in the shoots, while leaves had higher Ni, Cr, and Mn. The bioaccumulation factor of less than 1 (except for V) indicates limited bioavailibility of these metals.

Nymphaea lotus Distribution in Oguta Lake: Implications for Heavy Metal Pollution in Surface Water and Sediments

Water quality is increasingly deteriorating and has affected lakes, which are important sources of freshwater. Heavy metals are of great concern because they are mostly toxic and resistant to decomposition. Aquatic macrophytes serve as stable biological filters that purify water bodies by accumulating dissolved metals and toxins in their tissues. Given their ability to trap various toxic heavy metals, the macrophyte Nymphaea lotus, which is observed on the surface waters of Oguta Lake, was studied to estimate the concentrations of six heavy metals in the water, sediment, and macrophytes. This was achieved by studying the spatial and temporal distribution of Nymphaea lotus in the lake and analysing the concentrations of heavy metals in the surface water, macrophytes, and sediment samples. Descriptive statistics, exploratory data analysis, and correlation analysis were used to analyse data obtained. Results revealed that the population of Nymphaea lotus declines over time from June to November in all regions. Upstream had the highest concentration of macrophytes (64%), while the downstream area has the lowest (2%). The heavy metal concentrations in the three samples ranges from 0.16 mg/kg to 2.96 mg/kg in sediments and Nymphaea lotus, and from 0.16 mg/L to 2.16 mg/L in water, with lead showing the highest concentration across all sample type. This highlights heavy metal contamination in the lake. The sparsely populated Nymphaea lotus exhibits selective bioaccumulation of lead, mercury, and zinc, while it seems to exclude or inefficiently absorb arsenic and chromium. Correlation analysis suggests a close interdependence between the concentrations of metals in sediments, water, and macrophytes, with sediments playing a key role in both water contamination and macrophyte metal absorption. Corrective and preventive measures should be taken to restore the lake.

Assessment of heavy metal contamination in groundwater of rural areas of Kurdistan Province Iran: A comprehensive study

This study focuses on the contamination of groundwater by heavy metals (HMs) in the Kurdistan Province of Iran, an area heavily reliant on these water resources, especially in rural regions. This research aimed to quantify the concentrations of 20 HMs in groundwater sources and assess the associated health risks, including both carcinogenic and non-carcinogenic effects, for different age groups. The study was conducted in 2024. We collected 155 groundwater samples from water resources of the villages in Kurdistan Province, west of Iran. The study encompassed comprehensive sampling of groundwater from various wells and springs throughout the province, which was subsequently subjected to thorough laboratory analysis utilizing Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) for the quantification of heavy metal (HM) concentrations. The highest concentrations of As, Co, Cu, and Mo were 7.90, 0.22, 2.48, and 1.68 μg/l, respectively. It was related to the cities of Qorveh, Sanandaj, Baneh, and Qorveh respectively. A Health Risk Assessment (HRA) was performed, indicating that, while the concentrations of most HMs were within the thresholds established by national and international standards, certain metals, such as arsenic and lithium, presented notable non-carcinogenic risks, especially to children. These metals were responsible for over 48 % of the cumulative hazard index (HI) across all ten cities evaluated. Furthermore, the HI for the adult demographic exceeded 1.0 (specifically 1.23) exclusively in Qorwe city. The study also identified a high carcinogenic risk associated with lead across the province, which has a carcinogenic risk of 7.3 × 10−03 in 10 studied cities, which is more than the guideline value of 10−04. The findings underscore the urgent need for continuous monitoring and the implementation of preventive measures to safeguard public health. The results provide crucial insights for policymakers and health authorities, facilitating informed decisions to mitigate the health risks posed by HM contamination in the region's groundwater.

Breakthrough in soil remediation advancement: Nonthermal plasma powers polyvalent Ce-Mn (Hydro)oxide-enhanced nanographene to securely stabilize thallium-laden soils

The urgent need for remediation of thallium (Tl)-contaminated soils arises from its widespread presence as a poisonous heavy metal (HM), coupled with numerous challenges such as high costs, long durations, secondary pollution risks, and technological limitations. In the study, a novel approach has been introduced to the remediation of Tl-contaminated soils using calcium sulphoaluminate cement. This innovation involves the employment of nonthermal plasma-irradiated polyvalent Ce-Mn (hydro)oxide-modified nanographene (NTP-P-Ce-Mn-NGs) to intensify the cementation and immobilization of Tl species. The chemical speciation of Tl contaminants influenced by the dosage of NTP-P-Ce-Mn-NGs in the cementation was measured to explore the potential enhancement mechanisms brought by NTP-P-Ce-Mn-NGs in the sulphoaluminate cementation. Comprehensive strategies were adopted to explore the reaction pathways. In orthogonal (OD) experiments, compressive strengths ranging from 22.14 to 56.78 MPa in sulphoaluminate-cemented cubes were achieved. Remarkably, when NTP-P-Ce-Mn-NGs were introduced, the leached Tl concentration was reduced to 0.21–21.46 µg/L. This significant reduction was attributed to the NTP-P-Ce-Mn-NGs-induced more uniform hydration reactions and a more holistic microstructure. The presence of diverse valent Ce and Mn species within the matrix was confirmed, revealing a reliable interaction between NTP-irradiated high-valent Mn and Ce with monovalent Tl ions. This interaction induced multiple redox reactions, immobilizing Tl contaminants within the matrix and the cementation encapsulation. This study represents a significant milestone in Tl pollution control, paving the way for more efficient and cost-effective soil remediation strategies.

Capacity of an aquatic macrophyte, Pistia stratiotes L., for removing heavy metals from water in the Oued Fez River and their accumulation in its tissues.

Water resources, particularly rivers, are increasingly exposed to pollutants, especially heavy metals of chemical origin, which are difficult to monitor and can pose risks to both ecosystems and human health. This study assesses heavy metal contamination in the Oued Fez River, focusing on the bioaccumulation by the invasive plant Pistia stratiotes. The methodology involves measuring and comparing metal concentrations in water and plant tissues. Results revealed that while aluminium (Al) slightly exceeded recommended levels at 0.2978 mg L-1, other metals like zinc (Zn), iron (Fe), copper (Cu), lead (Pb) and cadmium (Cd) remained within acceptable limits. The study demonstrates P. stratiotes' effectiveness in heavy metal phytoremediation, with its roots showing high bioaccumulation up to 19,726 mg kg-1 for Fe and 15,128 mg kg-1 for Al, indicating its potential for water decontamination. Eco-toxicological assessments, including bioconcentration and translocation factors, confirm the plant's capacity to mobilize toxic metals. Statistical analysis also points to possible industrial, urban, or agricultural contamination sources based on correlations between Al, Fe and Zn. The study underscores P. stratiotes' role in phytoremediation while emphasizing the need for monitoring and controlling contamination sources and managing the spread of this invasive species to ensure sustainable water resources.

Enhancing the Phytoremediation of Heavy Metals by Plant Growth Promoting Rhizobacteria (PGPR) Consortium: A Narrative Review.

Heavy metal pollution has become a significant concern as the world continues to industrialize, urbanize, and modernize. Heavy metal pollutants impede the growth and metabolism of plants. The bioaccumulation of heavy metals in plants may create chlorophyll antagonism, oxidative stress, underdeveloped plant growth, and reduced photosynthetic system. Finding practical solutions to protect the environment and plants from the toxic effects of heavy metals is essential for long-term sustainable development. The direct use of suitable living plants for eliminating and degrading metal pollutants from ecosystems is known as phytoremediation. Phytoremediation is a novel and promising way to remove toxic heavy metals. Plant growth-promoting rhizobacteria (PGPR) can colonize plant roots and help promote their growth. Numerous variables, such as plant biomass yield, resistance to metal toxicity, and heavy metal solubility in the soil, affect the rate of phytoremediation. Phytoremediation using the PGPR consortium can speed up the process and increase the rate of heavy metal detoxification. The PGPR consortium has significantly increased the biological accumulation of various nutrients and heavy metals. This review sheds light on the mechanisms that allow plants to uptake and sequester toxic heavy metals to improve soil detoxification. The present review aids the understanding of eco-physiological mechanisms that drive plant-microbe interactions in the heavy metal-stressed environment.

Analysis and quantification of selected heavy metals and paraphenylenediamine in commercially available herbal black hair dyes in Sri Lanka

Currently, the use of henna-based herbal black hair dyes is widespread in the community. However, it is important to note that these dyes cannot be classified as completely natural due to the addition of various ingredients to enhance their effectiveness. Most black hair dyes use paraphenylenediamine (PPD) to get a black hue, however, PPD is widely recognized as a contact sensitizer. The toxicity of heavy metals is also prevalent in the cosmetics sector. These metallic elements can permeate the skin and provide widespread exposure throughout the body. Hair dye requires an alkaline pH value because of reactions that occur during the dyeing process, which is incompatible with scalp pH. The varying concentrations of these chemicals and their frequency of usage can result in diverse health issues. The present research implemented High-Performance Liquid Chromatography and Atomic Absorption Spectrometry to quantify the concentrations of PPD and heavy metals (Pb, Cd, and Fe) in seven frequently used brands in Sri Lanka. The lead content in the examined samples exhibited variability, ranging from 0.04 ± 0.01 ppm to 0.28 ± 0.14 ppm. However, all the samples remained below the allowed level of 2 ppm according to the BVL standard. Regarding Cd, certain examined materials surpassed the acceptable thresholds, while others did not and varied between 0 ppm and 2.33 ± 1.92 ppm. Iron was found at a significantly higher concentration compared to the other two heavy metals. A significant quantity of PPD was detected, exceeding the allowable threshold of 6 % according to the European Union legislation. All the samples that were analyzed had a pH value within the alkaline range. The study indicates that herbal dyes generated from natural materials may contain harmful compounds, such as a high concentration of PPD in herbal black hair color potentially inducing sensitization.

Enzymological Effects of Lead Acetate Exposure in Various Organs of Oreochromis mossambicus (Peters 1852)

The various enzymological effects of heavy metal Lead acetate (Pb(C2H3O2)2) exposed to fingerlings of Oreochromis mossambicus was analyzed in this study. The 30 days old fingerlings of O. mossambicus were exposed to sub lethal dose 3.80ppm of 96 hrs. LC50 of Pb(C2H3O2)2 for 21 and 28 days, various organs (liver, gill, kidney and muscle tissue) were removed from control and treated fishes and were used for various enzymological effect: Succinate dehydrogenase (SDH), Lactate dehydrogenase (LDH), Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Acid phosphatase (ACP) and Alkaline phosphatase ALP). The observed data were subjected into various statistical analysis by using IBM-SPSS version 26. Among the two different exposure periods 21 and 28 days which compared with control fingerlings organs, the various enzymological effects were drastically suffered (Treated fish enzymological levels were inversely proportionate towards the control groups of fish species) by 28 days of exposure periods. Pb(C2H3O2)2 exposed to fingerlings which tested on various organs at 28 days interval periods for assessing of SDH, LDH, AST, ALT, ACP and ALP of various organs of treated fish: Liver: 12.02, 55.75, 58.24, 125.27,12.26, 11.82 µ moles of phenol liberated/ mg of protein; Gill: 10.80, 33.75, 28.73, 28.11, 7.80, 8.63 µ moles of phenol liberated/ mg of protein; Kidney: 12.18, 46.33, 44.78, 75.40, 6.27, 10.38 µ moles of phenol liberated/ mg of protein and Muscle: 11.72, 32.44, 32.76, 44.20, 3.72, 7.20 µ moles of phenol liberated/ mg of protein were recorded on tissue of treated fish. The enzymological effect of Pb(C2H3O2)2 exposed towards O. mossambicus which observed various health defects on organism exposed to a particular toxicant. It may give sufficient information about heavy metal contamination on aquatic organism and would help us to propose policies to protect the ecosystem.

Monitoring of urinary nickel and chromium in metal industries workers in Alborz, Iran

Heavy metal contamination from occupational sources is a cause for concern due to its potential accumulation in the environment and the body of living organisms, which leads to long-term toxic effects. There is limited evidence on the concentration of heavy metals in the body fluids of welding workers. This study aimed to measure the concentration of nickel (Ni) and chromium (Cr) as two main toxic heavy metals in the urine samples of welders and determine the potential relationship of various environmental factors on their concentration levels. This study was conducted in Iran in 2022–2023. Eighty-five urine samples were collected from the studied welding workers. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to measure the concentration of Ni and Cr. Data related to socio-demographic characteristics (education level, income, work experience, age, and body mass index (BMI)), lifestyle profile (consumption of seafood and canned food, smoking, physical activity), type of ventilation and preventive devices at work, and suffering from underlying diseases (cardiovascular and high blood pressure) were collected using valid questionnaires. Ni and Cr were present in 100% of urine samples with mean concentrations of (1.09 ± 0.294) and (11.45 ± 16.751) µg/g creatinine, respectively. A significant correlation was observed between the mean concentration of Ni and Cr with the level of education, income, work experience, age, consumption of seafood and canned food, smoking, type of ventilation and preventive devices, and underlying diseases (p-value < 0.05). Also, there was no significant difference between Ni concentration and physical activity and Cr concentration with BMI. Lifestyle determinants and not using preventive devices are important predictors of urinary heavy metals in welding workers. Therefore, more research is required to determine the adverse effects of long-term exposure to these heavy metals.