Trace Heavy Metals Research Articles

Enhanced inhibition of heavy metal leaching in incineration bottom ash through accelerated carbonation with ammonium carbonate

The increasing generation of incineration bottom residues poses environmental risks due to heavy metal leaching, while carbonation is one of the effective methods to immobilize heavy metals. This study introduces a novel approach to mitigate heavy metal leaching from incineration bottom ash (IBA) by accelerated carbonation with ammonium carbonate solution. The effect of ammonium carbonate concentration on carbonation efficiency and inhibition of heavy metal leaching was systematically investigated. X-ray fluorescence was used to analyze the composition of IBA, and thermogravimetric analysis (TGA) and inductively coupled plasma optical emission spectroscopy/mass spectrometry were used to determine carbonation capacity and heavy metal leaching, respectively. Results showed that maximum carbonation capacity was achieved at 8 wt% ammonium carbonate concentration at a solid/liquid ratio of 1:5 for 1 h, but the increase in carbonation efficiency slowed down when the concentration exceeded 4 wt%. Ammonium carbonate accelerated carbonation effectively inhibited heavy metal leaching, particularly copper, with an 89% inhibition rate at 10 wt% ammonium carbonate, while diminished effects were observed with chromiun. The effect of the ammonium carbonate concentration on heavy metal inhibition became less significant above 4 wt%, revealing a nuanced relationship between carbonation and heavy metal leaching inhibition. TGA and X-ray diffraction analyses confirmed the formation of insoluble CaCO3 during carbonation, elucidating neomineralization processes that immobilize trace heavy metals. In addition, the study explored the impact of carbonation on leachate pH, emphasizing the interplay between pH reduction and heavy metal leaching inhibition.

AuNPs enhanced electrochemical and optical dual-mode fiber optic sensor for trace Hg2+ detection

Efficient and low-concentration detection of heavy metal ions is crucial for healthcare and environmental monitoring. Traditional fiber optic surface plasmon resonance (SPR) sensors face challenges in detecting trace heavy metal ions due to limited sensitivity and the need for complex specific modifications. To overcome these challenges, an innovative electrochemical and optical dual-mode fiber optic sensor for in situ, real-time detection of trace mercury ions is proposed in this paper. The sensor utilizes a reflection-type fiber optic probe coated with thin gold (Au)/indium tin oxide (ITO) film and gold nanoparticles (AuNPs), enabling simultaneous electrochemical and optical interrogation. The coupling effect between the SPR of thin film and the localized surface plasmon resonance (LSPR) of AuNPs significantly improves optical sensitivity, with AuNPs also offering additional active sites for the redox reaction of Hg2+. The ITO film not only facilitates the stripping of Hg2+, leading to sharper stripping peaks but also enhances the ability of the sensor to rapidly respond to anomalous potential changes. Experimental results show that the sensor has a wide dynamic detection range from 10−10 M to 10−5 M, with a limit of detection reaching the pM level. The dual-mode functionality allows the simultaneous collection of voltage, current, and optical information, enabling cross-validation of the detection results and improving the accuracy and reliability of detection.

Heavy metal (Pb, Cd and Cr) contamination and human health risk assessment of groundwater in Kuakata, southern coastal region of Bangladesh

This study investigates the quality of groundwater in Kuakata, a coastal area in southwestern Bangladesh, by analyzing the levels of lead (Pb), cadmium (Cd), and chromium (Cr) in 50 groundwater samples. The concentrations of these heavy metals were determined using atomic absorption spectrometry. The results indicated that while cadmium was not detected, significant levels of lead and chromium exceeded recommended safety thresholds. The contamination was evaluated using several indices, including the heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and degree of contamination (Cd). Health risk assessments for adults and children revealed potential non-carcinogenic and carcinogenic risks, particularly from lead. This study provides essential data to guide groundwater management and improve public health in the region. The groundwater samples contain traces of additional heavy metals including lead and chromium. The lead concentration ranges from 0.0003 to 0.1049 mg/L, while chromium ranges from 0.00074 to 0.1828 mg/L. The levels of certain substances in groundwater exceeded the maximum limit set by international and local health authorities for safe drinking water. Heavy metal evaluation index (HEI), along with the degree of contamination (Cd) and heavy metal pollution index (HPI), were used to assess the pollution load. The results of HEI and HPI revealed that a significant portion of the samples in the study area, specifically 34% and 38%, were found to be strongly and seriously affected, whereas 38% samples were within the highest values (>4) of Cd. Based on the hazard index (HI) and incremental lifetime cancer risk (ICLR) values, the deep groundwater in the coastal area presents a notable health risk to the local population, particularly children. This study provides essential data that can be used as a foundation for developing effective groundwater management strategies in the coastal region, with the ultimate goal of ensuring the availability of safe drinking water.

Eu-doped carbon dots-MOF based turn-on fluorescent probe for trace Hg2+ and Pb2+ and construction of the simultaneous detection model

Multiple trace heavy metal pollutants present a serious threat to the aquatic environment, and their coexistence also affected the detection efficiency. This work prepared Eu doped metal organic framework (MOF) complexed with S-containing carbon dots (CD(s)) exhibited dual-emission fluorescence. Its chelation-enhanced fluorescence with heavy metals replaced the original agglomerative fluorescence quenching of pure CD(s), which was utilized to construct a “turn on” fluorescence sensing probe. Based on the XPS, DFT and fluorescence lifetime results, the N, S functional groups on the surface of the materials could bind specifically to Hg2+ and Pb2+ with enhanced sensitivity. The limit of detection reached 76.67 nM for Hg2+ and 5.12 nM for Pb2+ within 2 min detection time. Furthermore, due to the different response mechanism of the two signal peaks to Hg2+ and Pb2+, a three-dimensional data model was developed for simultaneous detection in the co-existence system. The model had been successfully applied to actual Hg2+-Pb2+ containing water samples with recoveries ranged from 93.15 ∼ 105.08 %. The results provided a new strategy for simultaneous detection of trace environmental pollutants.

Exploring Spatial Dynamics of Water Quality in a Tropical Lake Affected by Aquaculture

Lake Maninjau, like many surface water bodies worldwide, faces significant water pollution challenges due to extensive aquaculture activities, making it an ideal site to study the impact of fish farming on water quality, which has contributed to eutrophication and declining water quality. This study investigates the physicochemical parameters and pollution levels in the lake, aiming to provide insights into its environmental health. In August 2022, a comprehensive sampling campaign was undertaken at nine stations within the upper layers of open water and littoral zones of Lake Maninjau. In situ measurements, including temperature, dissolved oxygen, and pH, were conducted, accompanied by water sample collection for laboratory analysis of trace elements and heavy metals. Our study revealed notable variability in water parameters across different sites, with surface water layers exhibiting the greatest differences. While certain parameters such as temperature and conductivity remain relatively stable, pH levels show a decreasing trend with increasing water depth. Dissolved oxygen levels vary widely, while oxidation–reduction potential indicates water pollution, particularly in littoral zones. Potassium dominance within cations likely suggests anthropogenic influences, notably from aquaculture activities, that may also contribute to nutrient enrichment and heavy metal pollution. Elevated levels of total nitrogen and ammonia underscore the lake’s moderate pollution levels, with heavy metals such as mercury exceeding permissible limits, posing risks to aquatic life and human health.

Bioaccumulation and Health Risk Assessment of Heavy Metals in Labeo rohita and Mystus seenghala from Jhelum River, Punjab, Pakistan

The bioaccumulation of trace elements and heavy metals in aquatic organisms is a critical environmental concern due to its potential impact on ecosystem health and human safety. This study investigated the level of trace elements and heavy metals bioaccumulation in Labeo rohita and Mystus seenghala from the River Jhelum in the district Khushab, Punjab, Pakistan. The concentration of calcium, magnesium, iron, nickel, copper, arsenic, cadmium, zinc, chromium, manganese, cobalt, and lead in the gills, liver, and muscle tissues of these fish was measured using inductively coupled plasma-mass spectrometry. Then, the extent of contamination and its possible health risks were assayed. Our findings indicate significant variations in the elemental and metal concentrations among different organs and between species, reflecting their diverse feeding habits and habitats. The health risk assessment based on the estimated daily intake, estimated weekly intake, maximum permissible intake, target hazard quotient, hazard index or total target hazard quotient, health risk index, and target cancer risk revealed potential risks to human consumers of these fish. This study emphasizes the need for continuous monitoring, as new data and insights are crucial for understanding and mitigating these risks. Strict regulatory measures are also necessary to safeguard public health and preserve the ecosystem of Jhelum River.

Spatial Distribution of Physical and Chemical Properties of Deep Sea Water in Xisha, South China Sea

Deep sea water (DSW) is a globally utilized source of renewable energy and other resources. To understand the characteristics of DSW resources in the South China Sea, in July 2022, the Guangzhou Marine Geological Survey (GMGS) investigated temperature, salinity, pH, dissolved oxygen (DO), inorganic salts (DIN, PO43−-P, and SiO3-Si), heavy metals (Hg, Pb, As, and Cd), trace elements (Cu, Zn, Fe, Mn, Ni, Se, and Mo), and other related indicators. The results of this investigation elucidate the horizontal and vertical changes in the physical and chemical properties of deep sea water in the Xisha Sea. The surface seawater quality in Xisha was found to be excellent and to meet first-class seawater survey standards. However, the concentrations of various nutrient salts in the surface layer were relatively low. As the seawater depth increased, different trace elements and heavy metals exhibited variations, and the concentrations of various nutrients also gradually increased.

Drinking Water Quality in Delta and Non-Delta Counties along the Mississippi River

The Mississippi Delta region has worse population health outcomes, including higher overall cardiovascular and infant mortality rates. Water quality has yet to be considered as a factor in these health disparities. The objective of this paper is to determine overall differences in basic water quality indicators, electrolytes of cardiovascular importance, trace elements, heavy metals, and radioactive ions of groundwater in delta and non-delta counties in states along the Mississippi River. Data were sourced from the major-ions dataset of the U.S. Geological Survey. We used the Wilcoxon rank sum test to determine the difference in water quality parameters. Overall, delta counties had lower total dissolved solids (TDS) (47 and 384 mg/L, p-value < 0.001), calcium (7 and 58 mg/L; p-value < 0.001), magnesium (2 and 22 mg/L; p-value < 0.001), and potassium (1.57 and 1.80 mg/L; p-value < 0.001) and higher sodium (38 mg/L and 22 mg/L; p-value < 0.001) compared to non-delta counties. Overall, there were no statistical differences in trace elements, heavy metals, and radioactive ions across delta versus non-delta counties. These results underscore the need for further epidemiological studies to understand if worse health outcomes in delta counties could be partially explained by these parameters.

On the transition of liquid dispersion states and their physical-thermodynamic nature in the development of gas-condensate reservoirs in depletion mode

This work presents new results of physical and chemical analysis of samples from contaminated areas of the Absheron field. The advantages and disadvantages of the used and traditional methods of cleaning oil waste are shown. Modern methods have been used to determine the characteristics of oil sludge samples from the Balakhany, Ramana, Surakhany, Bibiheybet fields of the Absheron Peninsula: oil sludge composition, viscosity, density, water content, chemical composition, temperature, cutting size, toxicity, volume, pH level, turbidity, BOD (biological oxygen demand), TDS (total dissolved solids). The main properties of oil sludge from the fields of the Absheron Peninsula are analyzed and compared. Chromatographic analysis (Agilent 7820A GC) allowed us to separate the oil waste and mixtures of the studied samples into individual compounds and components. The separation and determination of the components of the waste mixture by gas chromatography consisted of three stages: 1) Introduction of the sample into the chromatograph, 2) Separation of the sample into individual components, 3) Determination of the compounds contained in the sample. An inductively coupled plasma mass spectrometer (Agilent 7500 cs) with reaction cell was used for the efficient determination of trace heavy metals in petroleum waste. The ion lens unit used in the Agilent 7500cs provided high sensitivity measurements. Thus, trace metals were detected in the samples. A vacuum distiller (Retort Oil and Water Kit RROW-50) was used to quantify liquid and solids in drilling mud. Comparison of our oil sludge analysis results with field data demonstrates the effectiveness of these methods in identifying the composition of oil sludge for obtaining target products. From the studied wastes of the oil industry, it is possible to obtain special additives and use them, for example, for asphalt concrete. The dependences of oil sludge evaporation (of the Balakhany, Ramana, Surakhany, Bibieybet deposits) on air temperature and thermal resistance of the waterproofing material of the oil storage facility have been studied. The evaporation of components also depends on the concentration of oil sludge. Based on our sample analyses, it has been shown that the combined use of physicochemical and chemical methods makes it possible to purify oil sludge to acceptable limits. The dependences of oil evaporation on air temperature and the thermal resistance of the waterproofing material of an oil tank on the concentration of oil sludge have been established.

Thiol-functionalized MOF modified 3D printed monolithic microextraction array for analysis of trace Cd and Pb in human urine

Controlling the position, size, and shape of pores is a limitation of traditional monolithic preparation methods. The application of 3D printing technology offers high customizability, allowing the precise printing of pore positions, sizes, and shapes according to the designer's 3D model. Herein, by using Projection Microstereolithography (PμSL), we prepared a 3D-printed monolithic array with post-modification of thiol-functionalized metal-organic framework (MOF), and combined it with inductively coupled plasma mass spectrometry (ICP-MS) for the online analysis of trace Cd and Pb in human urine. To achieve array monolithic microextraction, six 3D-printed monolithic columns were modified with thiol-functionalized MOF-808 (MOF-808-SH), and were then assembled in the 3D printed extraction device incorporating gas valve and scaffold. The MOF-808-SH modified 3D-printed monolithic column exhibits excellent extraction performance to Cd2+ and Pb2+ due to rich active adsorption sites and hierarchical porous structure, and has long life span (>100 reused times). Under the optimized conditions, the limits of detection (LODs) are 3.5 and 17.6 ng L−1 for Cd2+ and Pb2+, respectively, with the relative standard deviations of 4.9 % and 8.2 % (0.1 μg L−1, n = 7), and the sample throughput is 11 h−1. To validate the accuracy of the method, the method was used to determine Cd and Pb in Certified Reference Materials of freeze-dried human urine, the determined results agree well with the certified values. This method was also successfully applied to the determination of trace Cd and Pb in real human urine samples. The developed method offers low LODs, robust anti-interference capability, high sample throughput, long reuse cycles, and automation analysis, showing great potential for the analysis of trace heavy metals in biological samples.

Trace elements and heavy metal(loid)s triggering ecological risks in a heavily polluted river-reservoir system of central Mexico: Probabilistic approaches

The contamination of trace elements and heavy metal(loid)s in water bodies has emerged as a global environmental concern due to their high toxicity at low concentrations to both biota and humans. This study aimed to evaluate the ecological risk associated with the occurrence and spatial distribution of Mn, Fe, Co, Cd, Ni, Zn, Sb, As, Tl, Cu, Pb, U, and V in the heavily polluted waters of an important river-reservoir system (Atoyac River Basin) in central Mexico, using two-level tired probabilistic approaches: Risk Quotient based on Species Sensitivity Distribution (RQSSD) and Joint Probability Curves (JPCs). The concentrations of these elements varied widely, ranging from 0.055 μg L−1 to 9200 μg L−1 and from 0.056 μg L−1 to 660 μg L−1, in both total and dissolved fractions, respectively. Although geogenic and anthropogenic sources contribute to the presence of these elements in waters, the discharge of untreated or poorly treated industrial wastewater is the main source of contamination. In this regard, the RQSSD results indicated high ecological risk for Mn, Fe, Co, Ni, Zn, and Sb, and medium or low ecological risk for As, Tl, U, and V at almost all sampling sites. The highest RQSSD values were found downstream of a large industrial corridor for Co, Zn, Tl, Pb, and V, with Tl, Pb, and V escalating to higher risk levels, highlighting the negative impact of industrial contamination on biota. The JPC results for these elements are consistent with the RQSSD approach, indicating an ecological risk to species from Mn, Fe, Co, Ni, Zn, and Sb in waters of the Atoyac River Basin. Therefore, the results of this study offer a thorough assessment of pollution risk, providing valuable insights for legislators on managing and mitigating exposure.

Removal mechanism of phosphorus in water by calcium hydroxide modified copper tailings

With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation.

Present Status Of Trace Elements And Heavy Metals In AyurvedicMedicines

The therapeutic benefits of Ayurvedic medicines are historically well known. Sometimes the concentration of trace and heavy metals can vary depending on their geographical sources, whichcan cause extremely harmful effects. Thus, one of the most important topics nowadays is the assessment of toxicity and safety of these Ayurvedic medicines. The presence of these constituents in the soil of the study area can be linked to the formation of toxicants of these harmful elements. They should be used with caution in the field as their uncontrolled ingestion can have harmful dangerous consequences on their consumers. Analysis by atomic absorption spectrometry allowedthe detection of trace and heavy metals. This paper discusses the current status of trace elements and heavy metals in Ayurvedic medicine. Along with this, the effects of trace elements and heavymetals on human health have also been explained. This research paper also contains about in whatway to determination of Trace element and heavy metal from ayurvedic medicines specially “Ras

Eco-friendly thiol-functionalized magnetic oxygenous carbon nitride nanocomposites for effective elimination of heavy metals

The increased pollution of water resources by toxic heavy metals poses a huge threat to the aqueous ecosystem. Since the low concentrations of heavy metals are often highly toxic but difficult to remove, novel efficient adsorbents still need to be explored. Herein, the superparamagnetic thiol-functionalized oxygenous carbon nitride nanocomposite (CNO/Fe3O4-SH) with multifunctional groups such as –NH2, –OH, –SH, and –COOH was fabricated by a simple and eco-friendly method. The maximum adsorption capacities of Pb2+, As3+, and Cd2+ ions on CNO/Fe3O4-SH at pH = 6 were 80.79, 71.78 and 66.19 mg/g, respectively, when their equilibrium concentrations were 20 mg/L. Under the equilibrium concentration below 0.01 mg/L, the adsorption capacities of these heavy metals over CNO/Fe3O4-SH were much higher than those of other adsorbents. The competitive adsorption investigations showed that the adsorption order in polymetallic solutions was Pb2+ > As3+ > Cd2+. Adsorption kinetics and isotherms studies indicated that the adsorption of Pb2+, As3+ and Cd2+ by CNO/Fe3O4-SH was attributed to monolayer adsorption and the adsorption process was controlled by chemical adsorption. The thermodynamic experiments showed that the adsorption processes were spontaneous and endothermic. After six adsorption/desorption cycles, CNO/Fe3O4-SH maintained its original morphology and adsorption ability, indicating its excellent regeneration performance, which had significant potential application in the decontamination of trace heavy metal ions in water.

Characteristics and environmental implications of coal fines at Hwange Colliery Company, Zimbabwe: A comprehensive analysis

The study investigates the characteristics and environmental implications of coal fines at Hwange Colliery Company in Zimbabwe, aiming to address gaps in understanding and propose sustainable management strategies. The research encompasses a comprehensive analysis, including particle size distribution, proximate properties, elemental composition of coal fines, water and soil quality analysis. Sample collection and analysis were conducted following standardized procedures, revealing significant variations among sites in terms of particle size distribution and proximate properties. The sieve analysis revealed that around 80 % of the coal fines passed through the 2 mm sieve. Sites A and B exhibited lower moisture content and higher carbon content in contrast to site C, possibly due to variances in disposal duration. With an average gross calorific value of 17.43 MJ/kg, the coal fines showcase notable potential for energy extraction. Elemental analysis uncovered traces of heavy metals like Fe, Co, Cr, Ni, and Cu, posing an environmental risk if not managed appropriately. The water quality analysis revealed generally low turbidity levels in groundwater, with readings ranging from 0.34 to 0.55 NTU. However, elevated sulfate concentrations in some samples, averaging 113.67 mg/l, coupled with traces of nickel at levels up to 0.07 mg/l, warrant continuous monitoring to ensure compliance with safety standards. Soil analysis indicated the presence of heavy metals near coal fines dump sites, with lead levels reaching up to 52.32 mg/L, nickel at 36.17 mg/L, and copper at 53.70 mg/L, impacting soil enzyme activity and agricultural productivity. The study emphasizes the importance of improved waste management practices and sustainable utilization strategies to mitigate environmental risks and enhance resource efficiency in coal mining operations.

Preparation, Quality control and Standardization of a Destructive Distillate <i>Swasakasa Nei</i> (SKN), A Traditional Siddha Herbal Pharmaceutic for <i>Swasakasam</i> (Bronchial Asthma)

Standardization is essential to ensure the quality and reliability of traditional medicines. This study aimed to collect, authenticate and purification of raw materials, preparation of <i>Swasakasa Nei</i> (SKN) according to SOP, and Quality evaluation and Standardization procedures following Pharmacopoeial Laboratory of Indian Medicine (PLIM) guidelines. SKN, prepared as <i>Kuzhithylam</i>, is used to treat <i>Swasakasam</i> (Bronchial Asthma) in the Siddha system of medicine. The organoleptic characters of <i>Swasakasa Nei</i> reveal that SKN was a black, thick semisolid with a smoky odour, greasy consistency, and free-flowing nature drug. Physicochemical analysis showed values for Saponification Value (202.19), Iodine Value (30), Acid Value (7.25%), Peroxide Value (0.58%), Refractive Index (1.462), Specific Gravity (0.9131 g/ml), Loss on Drying (34.17%), Total Fatty Matter (60.18%), Free Fatty Acids (1.06%), and Unsaponifiable Matter (0.98%). The congealing point was 19°C, with no mineral oil and definite oxidation on rancidity. HPTLC fingerprint analysis revealed multiple prominent peaks at various wavelengths. Microbial contamination tests showed no specific microbes, and aflatoxin assays confirmed SKN was free from Aflatoxins B1, B2, G1, and G2. Pesticide residue analysis detected no organochlorine, organophosphorus, or pyrethroids, and heavy metal analysis showed no trace elements or heavy metals. These standards affirm the authenticity, genuineness, and safety of SKN, contributing to its scientific validation.

Determination of Trace Heavy Metals Content of Various Herbal Drinks Marketed in Ilorin Metropolis, Nigeria

The study encompasses an evaluation of the health risk and hazard profiles of heavy metals contents in various herbal drinks (AGBO) products marketed in Ilorin metropolis, Nigeria. Twenty (20) herbal drinks samples from four (4) different study (saw-mil, Osere, Oja-oba and Oke-odo) areas were collected randomly, digested and analyzed. Zinc, Lead, Copper, Iron, Manganese, Cadmium, Chromium and Nickel were analyzed using Atomic Absorption Spectrometer. The results of this study indicated that most of the heavy metals (Zn, Pb, Cu and Mn) in the herbal drinks were below the WHO recommended permissible limits. Chromium (Cr) and Cadmium (Cd) are not detected in all of the herbal drinks analyzed. However, sample C2 and D2 among other analyzed herbal samples contained unsafe concentrations of iron (Fe) and nickel (Ni) that exceeded the WHO recommended permissible limits. From the health point of view, the EDIs value of all the herbal drinks are below the daily reference dose. The non-cancerous (HQ) and hazard index (HI) value of all the herbal samples are less than one (1). Based on the results obtained in this study, there would be a non-carcinogenic health risk and hazard effects to the people taking and consuming the herbal drinks marketed in all the study areas.

Water quality dynamics and underlying controls in the Halton Region, Ontario.

We assessed the hydrochemistry of 15 watersheds in the Halton Region, southern Ontario, in high resolution (n > 500 samples across n > 40 streams) to characterize water quality dynamics and governing controls on major and trace element concentrations in this rapidly urbanizing region. In 2022, major water quality parameters were generally in line with historic monitoring data yet significantly different across catchments, e.g., in specific conductance, turbidity, phosphate and chloride, and trace element concentrations. Distinct hydrochemical signatures were observed between urban and rural creeks, with urban stream sections and sites near the river mouths close to Lake Ontario having consistently higher chloride (up to 700mg/L) and occasional enrichment in nutrients levels (up to 8 and 20mg/L phosphate and nitrate, respectively). Particularly upper reaches exhibited hydrochemical signatures that were reflective of the catchment surface lithologies, for instance through higher dissolved Ca to Mg ratios. Unlike for chloride and phosphate, provincial water quality guidelines for trace elements and heavy metals were seldom surpassed (on < 10 occasions for copper, zinc, cadmium, and uranium). Concentrations of other trace elements (e.g., platinum group elements or rare earth elements) were expectedly low (< 0.3µg/L) but showed spatiotemporal concentration patterns and concentration-discharge dynamics different from those of the major water quality parameters. Our results help improve the understanding of surface water conditions within Halton's regional Natural Heritage Systems and demonstrate how enhanced environmental monitoring can deliver actionable information for watershed decision-making.

Evaluation of Heavy Metal and Specific Trace Elements Levels Among Fast-Food Workers and Their Susceptibility to Atherosclerosis.

Fast-food workers in Iraq face significant health risks due to exposure to heavy metals from fumes and dust during cooking activities. Heavy metals, such as lead (Pb), cadmium (Cd), and nickel (Ni), are toxic to cells even at low concentrations and can cause health risks, including atherosclerosis, due to oxidative stress and reduced antioxidant activity. To the best of our knowledge, this is the first study assess the levels of heavy metals in fast-food workers and investigate their potential link to atherosclerosis development by monitoring the levels of copper (Cu), zinc (Zn), magnesium (Mg), manganese (Mn), and iron (Fe). A total of 120 male participants aged between 20 and 40 years were included in the study, with 40 fast-food workers, 40 patients with atherosclerosis, and 40 healthy individuals evaluated. The levels of Pb, Cd, Ni, Cu, Zn, Mg, Mn, and Fe in all blood samples were determined using atomic absorption spectrometry. Results showed that the fast-food worker group had significantly higher levels of Pb, Cd, Cu, and Fe compared to the healthy control group, with increases of 57%, 75%, 30%, and 55%, respectively. Conversely, their levels of Zn and Mg were significantly lower, decreasing by 15% and 16%, respectively. On the other hand, the atherosclerosis patients' group had significantly higher levels of Pb, Cd, Cu, and Fe, with increases of 47%, 74%, 34%, and 28%, respectively, as well as significantly lower levels of Zn and Mg, decreasing by 17% and 21%, respectively, compared to the control group. These findings suggest that fast-food workers are at risk of developing atherosclerosis due to exposure to high levels of heavy metals and imbalances in essential trace elements. The results showed a significant increase in the levels of Pb and Cd in the sera of these workers, which was expected because of the long duration and high intensity of exposure to toxic heavy metals. This is a serious indicator that must be considered, as it has been previously established that increased levels of Pb and Cd in the body are linked to the risk of atherosclerosis. Additionally, an association between Pb and Cd levels and an imbalance in trace element levels (Cu, Zn, Mg, and Fe) were observed. The Implementation of stricter regulations and guidelines for maintaining cleanliness and safety in fast-food restaurants may be crucial for protecting workers and preventing long-term health complications.

Simultaneous quantification of trace heavy metals in mushrooms using a three-dimensional highly reduced graphene oxide/Fe 3O 4 nanocomposite-based electrochemical sensor

Simultaneous quantification of trace heavy metals in mushrooms using a three-dimensional highly reduced graphene oxide/Fe ₃O ₄ nanocomposite-based electrochemical sensor