Low Levels Of Metals Research Articles

Hepato-renal toxicity of low dose metal(oid)s mixture in real-life risk simulation in rats: Effects on Nrf2/HO-1 signalling and redox status

The understanding that humans are exposed to a low level of toxic metals and metalloids in their lifetime has resulted in a shift in scientific and regulatory perspectives from the traditional evaluation of single metal toxicity to complex mixtures, relevant to real-life exposure. Therefore, the aim of this study was to examine the impact of real-life, 90-days exposure to mixture of toxic metal(oid)s, Cd, Pb, Ni, Cr, As and Hg, on the nuclear factor erythroid 2–related factor 2 and hemoxygenase-1 (Nrf2/HO-1) signalling and redox status by assessing total sulfhydryl groups (SH), glutathione (GSH), superoxide dismutase activity (SOD), malondialdehyde (MDA), and ischemia modified albumin (IMA) in the liver and kidney of Wistar rats. Animals (20 males and 20 females) were randomized in 2 control and 6 treated groups that received by oral gavage mixture of metal(oid)s solutions in doses that reflect blood metal(oid) levels determined in previous human biomonitoring study as benchmark dose (F/M _BMD), median (F/M _MED), and 95th percentile (F/M _95). Our results have shown that metal(oid)s mixture impaired the activation of the Nrf2/HO-1 pathway in the kidney and liver of male rats and kidney of female rats, followed by depletion of GSH levels in males. Additionally, in males elevated levels of IMA in the liver were observed, while in both genders increased MDA levels were observed in the kidney. Interestingly, the effects were more pronounced in male than in female rats. This study is among the first that examined hepato-renal toxic mechanisms of real-life metal mixture exposure, while our results might be of immense importance for assessing the risk of exposure to mixtures of toxic substances.

Recent Developments in Low Temperature Wafer Level Metal Bonding for Heterogenous Integration

An overview of various low temperature (<200°C) wafer bonding processes using metal interlayers is presented. Such processes are very attractive for novel applications in 3D heterogenous packaging as the allow for simultaneous formation of electrical interconnects, as well as hermetic encapsulation of various sensors and microelectromechanical systems-based devices. Metal wafer bonding is a generic category of processes consisting of various sub-categories, each one defined by the different principles governing the process. One can differentiate between eutectic wafer bonding (a eutectic alloy is formed as bonding layer during the process by liquid-solid interdiffusion), intermetallic wafer bonding (an intermetallic alloy is formed as bonding layer during the process by solid-liquid interdiffusion, process known also as Solid Liquid Intermetallic Diffusion – SLID or Transient Liquid Phase – TLP), and metal thermo-compression (TC) wafer bonding. Different critical/gating parameters were investigated and their impact for generally reducing processing temperatures for the different metal bonding systems was studied.

Alkyl Dicarbonates, Common Electrolyte Degradation Products, Can Enable Long-Lived Li-Ion Cells at High Temperatures

A common degradation product dimethyl-2,5-dioxahexane carboxylate (DMOHC) produced in Li-ion cell electrolytes after ageing is used here as an electrolyte solvent, allowing Li-ion cells to operate at high temperatures (70 °C and 85 °C) with excellent capacity retention and low impedance growth. Viscosity and conductivity values are reported for various DMOHC and diethyl-2,5-dioxahexane carboxylate (DEOHC) blends with dimethyl carbonate (DMC) and diethyl carbonate (DEC). Charge-discharge cycling data are reported for LiFePO4/graphite (LFP), Li[Ni0.5Mn0.3Co0.2]O2/graphite (NMC3.8 V, balanced for 3.8 V cut-off), Li[Ni0.6Mn0.4Co00]O2/graphite (NMC640, balanced for 4.1 V cut-off) and Li[Ni0.83Mn0.06Co0.11]O2/graphite (Ni83, balanced for 4.06 V cut-off) pouch cells at 70 °C and 85 °C. Pouch cells with DMOHC electrolyte have extraordinarily long lifetimes at 70 °C and 85 °C Pouch cells containing DMOHC-based electrolytes produce little to no gas compared to traditional ethylene carbonate (EC) based electrolytes. Cells taken apart after testing showed uniform negative electrode lithiation and no differences in the cell components were observed when using DMOHC electrolytes compared to EC. Lastly, micro X-ray fluorescence spectroscopy analysis was performed to probe the degree of transition metal deposition on negative electrodes of cycled cells. Very low levels of transition metals were found on the negative electrode even for cells tested at 85 °C. DMOHC is a co-solvent that can enable Li-ion batteries with exceptional high temperature lifetimes.

ANALYTICAL STUDY OF SAPTAMRITA LAUHA: AN AYURVEDIC HERBO-MINERAL FORMULATION

Saptamrita lauha is one of the herbo-mineral formulations. In Ayurveda classics, there are so many references available for Saptamrita lauha. The formulation distinctively improves eyesight and haemoglobin by its properties chaksushya (good for eyesight) and raktavardhak (haematinic). Standardization of formulation is essential in order to evaluate the quality of formulation. Making tablets from herbo-mineral drugs will aid in uniform dosage form, better palatability and easy acceptability in children. The pharmaceutical analysis method of Saptamrita lauha formulation was done according to the API and drug testing protocol of the Pharmacopoeial laboratory for Indian Medicine (PLIM). Materials and Methods: The prepared drugs were evaluated for organoleptic study, physicochemical study, pH value and microbiological studies for developing standards. Result: Due to low levels of heavy metals and lack of pathogenic bacteria, the formulation is safe for use. Conclusion: The results of pharmacognostical and pharmaceutical parameters have generated data that could be used as a fingerprint for future research. This paper presents the analytical study of the formulation.

Evaluating Alternative and Sustainable Food Resources: A Review of the Nutritional Composition of Myctophid Fishes

Additional and alternative sustainable food resources are needed as the global human population increases. Marine fishes have long provided essential nutrients, such as omega-3 long-chain (≥C20) polyunsaturated fatty acids (n-3 LC-PUFA), protein, and vitamins to meet human dietary requirements and feed for agricultural production. Many current commercial fish stocks are depleted or fully exploited, but oceanic mesopelagic fishes, particularly the myctophids (lanternfishes), represent a potentially very large and unfished resource. This review analysed the literature on nutritional and biochemical compositions of myctophids as a first step towards understanding the health benefits and risks of consuming them. We found that myctophids have high levels of protein (11–23% wet weight, WW) and variable lipid content (0.5–26% WW). In most species, desirable triacylglycerols or phospholipids dominated over less-desirable wax esters, and most have abundant amounts of health-promoting n-3 LC-PUFA, such as DHA and EPA. Myctophids have low levels of heavy metals and persistent organic pollutants. Most nutritional information is available for species from the Pacific and Southern Oceans and for the genera Benthosema, Electrona, and Diaphus. Myctophids generally possess favourable nutritional profiles, but major gaps in knowledge regarding their stock assessment, ecology and the economic viability for their harvest are barriers to developing sustainable fisheries.

Contamination of Southern Iraq Waterways

In this study a certain chemical elements Cu, Mn and Pb were ‎determined in water, and another set of Cd, Cu, Fe, and Zn were ‎determined in sediments from selected sites (1) Qurnah, (2) Al-‎Noor Bridge, (3) Saad Bridge, (4) Sindbad Island, (5) Al-Ashar, ‎‎(6) Abu Al-Khaseeb, (7) Seebah, and (8) Al-Faw along the ‎Southern Iraqi water ways during the year 2015. Low levels of ‎heavy metals were recorded in the water of Shatt Al-Arab river, ‎they were in the range 0.00735 - 0.02090, 0.00505 - 0.02145, ‎and 0.00150 - 0.0837 µg/l for Cu, Mn, and Pb respectively, and ‎lower values recorded were for the toxic Pb metal. On the other ‎hand levels of heavy metals in the sediments were little bit high ‎and in the range 0.1172488 - 0.614806, 17.175343 - 40.156639, ‎‎8156.970 - 21021.63, and 31.864781 - 79.160779 µg/g dry ‎weight for Cd, Cu, Fe, and Zn respectively. Fe recorded the ‎highest levels of heavy metals in all sites due to the nature of the ‎sedimentary valley in Iraq. Low levels of heavy metals Cu, Fe, ‎and Zn were recorded in the sediments of Seebah (site no.7) due ‎to the effect of sediment movements through Karun River from ‎the Iranian territories. More over levels of all investigated heavy ‎metals were recorded high values in the water from Ashar (site 5) ‎due to corrosion of marine vessels sunk in the area since the Iraqi-‎Iranian War 1980-1988.‎

Drinking water as a substantial source of toxic alkali, alkaline and heavy metals: Toxicity and their implications on human health

ObjectivesThe objective of the current study was to optimize a highly sensitive method utilizing microwave digestion and iCAP quadrupole inductively coupled plasma mass spectrometry (Q ICP-MS) for the determination of toxic alkali, alkaline and heavy metals in drinking water, and their implications on human health. MethodsA highly sensitive method based on microwave digestion and iCAP Q ICP-MS have been applied for the determination of potential metals alkali (23Na), alkaline (24 Mg) and heavy metals (75As, 208Pb, 111Cd, 59Co, 66Zn and 63Cu) in drinking water of diverse brand and origin. ResultsThe system has provided excellent quality conditions, such as detection limit (DL, 0.007–0.296 µg/L), quantification limit (QL, 0.023–0.893 µg/L) and coefficient of determination (R2, 0.976–0.998) with recovery >99.95%. Amounts of metals in bottled drinking water (BDW) were ranged from not detected to 74847.15 µg/L, whereas, tap water (TW) constitutes 1.12 to 42776.89 µg/L. Average daily dose (ADD, 0.03–516.715 μg/kg/day), hazard quotient (HQ, 0.001–0.08 μg/kg/day) based on heavy metals oral reference dose, and cancer risk (CR, 0.45–244.67 μg/kg/day) based on heavy metals cancer slope factor were achieved for BDW. Nevertheless, ADD (0.03–1028.19 μg/kg/day), HQ (0.01–0.12 μg/kg/day) and CR (0.42–292.80 μg/kg/day) were obtained for TW. As a result, BDW produced lower toxicity values than TW (high risk). Additionally, BDW was found to be brand specific, particularly for international brands that contained zero or very low levels of metals. ConclusionsCurrent investigations have explored the possible impacts of progressively increasing consumption of drinking water, especially in Saudi Arabia. Up to the present time, the levels of potential heavy metal in such water pose predominantly higher toxicity values in TW. Besides, BDW was found to be the brand specific particularly the international brand which contained either zero or low level of metals. As a result, the results highlight the need for strict policies to address the threat of metals in public water.

Proximate and mineral composition of some wild leafy vegetables consumed in Katsina State Nigeria

In Sub Saharan Africa, people utilised wild leafy vegetables and herbs in order to meet the daily recommended nutritional requirements for the betterment of health and general well being, In this study, seven wild leafy vegetables consumed in Katsina State, Nigeria were studied for their proximate analysis and mineral composition. B. salicifolia (Capparaceae), T. globiferus (Loranthaceae), F. glumosa (Moraceae), C. religiosa (Capparaceae), M. angolensis (Capparaceae), S.occidentalis (Fabaceae) and P.thonningii (Fabaceae), were evaluated using standard methods. The results showed that, Carbohydrates is the most abundant nutrient present in the selected plants. The crude protein ranged from 13.23– 9.33.% with F. .glumosa and B. salicifolia providing the highest amount. The elemental analysis in ppm/l revealed the presence of Iron, Calcium within recommended daily values and low level of heavy metals in all the samples. The selected plants may therefore be considered as viable and cheap sources of dietary nutrients and their incorporation in diets may be said to be scientifically justifiable..

Monte Carlo-based probabilistic risk assessment for cement workers exposed to heavy metals in cement dust.

This study assessed the carcinogenic and non-carcinogenic health risks of cement plant workers exposed to chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) in cement dust using a probabilistic approach. Air samples were collected according to NIOSH 7900 and OSHA ID-121 methods and analyzed by an graphite furnace atomic absorption spectrometer. The EPA inhalation risk assessment model and Monte Carlo simulation were utilized to assess the health risks. Sensitivity analysis was used to determine the influencing parameters on health risk. The average concentrations of As and Pb exceeded the occupational exposure limit (OEL), reaching a maximum of 3.4 and 1.7 times the OEL, respectively, in the cement mill. Individual metals' cancer risk exceeded the 1E-4 threshold in ascending order of Cd < As < Cr. The mean cancer risk of Cr ranged from 835E-4 (in raw mill) to 2870E-4 (in pre-heater and kiln). Except for Cd, the non-cancer risk of metals exceeded the standard (hazard index, HQ = 1) in the ascending order of Pb < As < Cr. The mean HQ of Cr ranged from 162.13 (in raw mill) to 558.73 (in pre-heater and kiln). After adjusting for control factors, the cancer and non-cancer risks remained over the respective recommended levels. Sensitivity analysis revealed that the concentration of Cr was the most influential parameter on both carcinogenic (78.5%) and non-carcinogenic (88.06%) risks. To protect the health of cement factory employees, it is recommended to minimize cement dust emissions, implement job rotation, and use raw materials with low levels of heavy metals.

The Effects of Coexisting Elements (Zn and Ni) on Cd Accumulation and Rhizosphere Bacterial Community in the Soil-Tomato System

The increasing cadmium (Cd) levels in agricultural soils have become a worldwide concern for food crop security. Cd accumulation in the soil-plant system is closely related to other coexisting factors. In this study, the effects of different levels of Zn or Ni on Cd accumulation in tomato plants and on the rhizosphere soil bacterial community structure were analyzed by coupling pot experiments with high-throughput sequencing. The results demonstrated that tomato plants (Lycopersicon esculentum) in Zn-Cd and Ni-Cd co-contaminated soils exhibited lower relative growth rates. Co-contamination at low levels tended to reduce the bioaccumulation of heavy metals in the roots of plants, whereas increased contaminant concentrations produced the opposite effect. In the presence of 200 mg/kg Zn or 20 mg/kg Ni, the biomass of plant roots increased by 4.95–23.16% and the Cd content of the plant roots decreased by 17.36–68.93% due to the antagonistic effects between Cd and Zn/Ni. In addition, the richness and diversity of the bacterial community were significantly altered under HMs co-contamination, and the number of special bacteria was positively correlated with the level of heavy metals in the rhizosphere soil. The relative abundance of Proteobacteria increased and that of Actinobacteria decreased in soils with low levels of heavy metals. This may improve the tolerance of plant roots to heavy metals and reduce the accumulation of Cd in plant roots. These findings highlight the important role of coexisting elements in the inhibition of Cd accumulation in tomatoes and offer important information for the production of safe crops.

Effects of mango leaves utilization during postharvest storage of tomatoes on some macroelements (Na, K, Ca, M, and P) concentrations in Sokoto, Nigeria

The objective of this study is to determine the effect of mango leaves in preserving the varied concentrations of metals (sodium, potassium, calcium, magnesium, and phosphorus) present in two tomato varieties in Sokoto, Nigeria. After the application of different mango leaves extracts in the postharvest preservation of Daneka tomato fruits in a randomized control design, and atomic absorption spectrophotometry of macro elements; the most elevated concentrations noticed significant difference at (p&lt;0.05) were revealed in potassium (1.20±0.002 to 3.00±0.001 ppm), and calcium (1.27±0.003 to 2.15±0.002 ppm). The lower levels of metals noticed upon storage under mango leaves are revealed by phosphorus (1.10±0.002 to1.37±0.002 ppm), and sodium (0.90±0.001 to 1.30±0.001 ppm); and the least was revealed by magnesium (0.61±0.001 to 0.86±0.001 ppm). The different concentrations of elements upon addition of mango leaves in the postharvest preservation of UTC tomatoes in Sokoto, Nigeria show, the elevated concentrations revealed by phosphorus (2.5±0.001 to 3.8±0.004 ppm), potassium (2.00±0.001 to 2.99±0.001 ppm), and magnesium (1.01±0.001 to 2.59±0.001 ppm). The lower concentrations were observed in calcium (1.34±0.001 to 1.70±0.001 ppm), and sodium (0.55±0.005 to 1.80±0.002 ppm). The mango leaves possessed potential to preserve the Na, K, Ca, Mg, and P levels in tomatoes; thus could serve as cheap, accessible, and sustainable preservative in the state when improved.

Ocean warming and CO2-driven acidification can alter the toxicity of metal-contaminated sediments to the meiofauna community

Interactive effects of trace metal contamination, ocean warming, and CO2-driven acidification on the structure of a meiofaunal benthic community was assessed. Meiofauna microcosm bioassays were carried out in controlled conditions in a full factorial experimental design which included three fixed factors: metal contamination in the sediment (3 levels of a mixture of Cu, Pb, Zn, and Hg), temperature (26 and 28 °C) and pH (7.6 and 8.1). Metal contamination caused a sharp decrease in the densities of the most abundant meiobenthic groups and interacted with temperature rise, exacerbating deleterious effects for Nematoda and Copepoda, but mitigating effects for Acoelomorpha. CO2-driven acidification resulted in increased acoelomorphs density, but only in sediments with lower levels of metals. Copepod densities, in turn, were lower in the CO2-driven acidification scenario regardless of contamination or temperature. The results obtained in the present study showed that temperature rise and CO2-driven acidification of coastal ocean waters, at environmentally relevant levels, interacts with trace metals in marine sediments, differently affecting the major groups of benthic biota.

Urban soil quality deteriorates even with low heavy metal levels: An arthropod-based multi-indices approach.

Urban-induced habitat conversion drastically changes soil life in a variety of ways. Soil sealing, human disturbance, habitat fragmentation, industrial and vehicular pollution are the main causes of urban soil degradation. Soil arthropods, as one of the most abundant and diverse group of soil fauna, are involved in many soil processes that are of great importance in maintaining soil health and multifunctionality. Nevertheless, soil quality is still mainly characterized by physical, chemical, and microbiological parameters. Here, we assessed and compared the biological soil quality in woody (REF: reference forest, REM: remnant forest) and nonwoody (TURF: public turfgrass, and RUD: ruderal habitat) types of urban green spaces along a disturbance and management intensity gradient in the Budapest metropolitan area (Hungary), using community metrics and soil arthropod-based indicators. Vegetation cover and landscape characteristics of study sites were quantified through vegetation and urbanization indices, respectively. Basic soil properties, total and bioavailable concentrations of the main heavy metals (Cd, Co, Hg, Ni, Zn) were also measured. Acari, Collembola, and Hymenoptera (mainly Formicidae) were the most abundant groups. Litter-dweller taxa, particularly Protura, proved to be the most sensitive to urban disturbance. Representatives of Hemiptera, Diptera, Symphyla, and Pauropoda were common in low densities. The taxonomic diversity of soil arthropod assemblages in nonwoody and woody habitats was similar. Although the integrated faunal indices showed no differences among soil habitat types, they provided different responses and, consequently, different information. Our findings demonstrated that the biological quality and arthropod community structure of soils were strongly impacted by soil C/N and heavy metal contamination. We found that low and moderate levels of pollution have adverse effects on edaphic fauna, suggesting biological degradation of soils, even below pollution limits. Nevertheless, more disturbed urban green spaces have been shown to play a significant role in maintaining belowground biodiversity, thereby soil functions.

Evaluation of Water Quality in Al-Dalmaj Marsh Environment by Using some Pollution Indicators

In this paper, water was sampled in ten sites of the Dalmaj marsh in Iraq. Using a pollution index, total concentrations of heavy metals were evaluated to look into their distributions and pollution levels. The degree of pollution of water for cadmium, lead, chromium and iron was assessed using the heavy metals pollution index (HPI) and heavy metals evaluation index (HEI) and contamination degree (CD). Results showed that by using pollution indexes, the HPI, HEI, and CD were classified as medium to high in all sites. The water of the marsh was more contaminated because of the continuous addition of these metals imported from discharges of wastes to the Euphrates River that ends up on this marshland water surface. Thus, it confirms that there was a potential contamination of heavy metals, especially in water and sediments. These concentrations need more attention and consideration to either maintain the low level of heavy metals or keep them even lower.

Engineering Properties of Cementless Alkali Activated CLSM Using Ferrochrome Slag

This manuscript aims to utilize industrial wastes, i.e., ferrochrome slag (FS), ground granulated blast furnace slag, and fly ash to prepare alkali activated cementless controlled low strength material (CLSM). The physical properties, i.e., flowability, bleeding, unit weight, and mechanical properties such as strength, durability, and settlement were assessed for different CLSM mix designs and compared with cement-based FS-CLSM. The alkali activated FS-based CLSM achieved adequate flowability and unit weight with a strength value of 1.72 to 10.44 MPa for different CLSM mix propotions, with a California bearing ratio (CBR) value of 328% to make the CLSM mix a feasible pavement material. The study concludes that a high molar ratio of potassium hydroxide (KOH) accelerates the alkali activation process which helps in the formation of alkaline alumino/calcium silicate hydrates to bind the FS and produce CLSM with adequate strength. The high durability and low levels of toxic metals in the leachate cause the FS-based CLSM environment to be acceptable. Furthermore, life cycle analysis was carried out to investigate the effects of the FS-based CLSM on the ecosystem and human health.

Health Risk Assessment of Some Heavy Metals in Lipsticks Sold in Local Markets in Iraq

Heavy metals found in cosmetics are a safety threat to the health of consumers. Therefore, in this study, we evaluated the levels of heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), zinc (Zn), and arsenic (As) in lipstick makeup. The level of heavy metals in lipstick was discovered by using an analytical technique with high selectivity and sensitivity, namely atomic absorption spectrometry. Twenty lipsticks were selected from the same brands, yet differing in price. Ten original (expensive) and ten knockoff (cheap) lipsticks were chosen from shops in Diyala, Iraq. The detection-limit (LOD) was in between 0.01 and 0.1, the quantification-limit (LOQ) was within 0.03 and 0.33, the recovery values (Rec.%) ranged from 100.17% to 101.1%, the RE values were 0.81%, and the RSD values were 1.33%. The results also revealed that the levels of metals are in the order of Pb &amp;gt; Cd &amp;gt; Zn &amp;gt; Cu &amp;gt; As &amp;gt; Cr. However, the levels of heavy metals that were estimated in this study were less than the permissible limit set by the executive authorities, so there seems to be no concern associated with these heavy metals. However, the daily and frequent use of lipstick by women exposes them to low levels of toxic metals as these metals accumulate over time and pose adverse effects on the health of the users. The results of the hazard quotient (HQ) and health risk index (HI) indicate there was no harmful effect on human health related to heavy metals present in lipstick. Whereas the results of the biological activity of the samples indicated that there was no bacterial growth in expensive samples, cheap samples were contaminated with some types of organisms; this indicates poor quality.

Interaction of Metals, Menopause and COVID-19-A Review of the Literature.

A growing number of reports point to the possible role of environmental factors in determining the age of onset of menopause. Specific metals, such as mercury, cadmium, arsenic and lead can lead to fertility disorders, to endocrine dysregulation, and in addition, their high blood concentrations correlate with the onset of menopause. Changing concentrations of hormones in the blood during this period of a woman's life can also have an impact on SARS-CoV-2 infection, and excessively high or low levels of metals may also be an important predictor for the course of COVID-19. Postmenopausal women are exposed to greater risk of serum biochemical changes, and with the possibility of nutritional disturbances, particularly involving trace minerals, the risk of age-related diseases is very high during this period. These adverse changes in serum trace minerals should be taken into consideration for the early diagnosis and prevention of menopause-related diseases. Dietary supplementation may be necessary, especially where levels are significantly reduced. We performed a manual search of scientific articles cited in major electronic databases (PubMed, EMBASE, Web of Science and Google Scholar) in November 2022 to identify studies relevant to the relationship between metals, COVID-19 and menopause. The effects of metals on the course of menopause is a broad topic and should certainly still be a subject of research, due to, among other things, continuing environmental pollution and the use of metals in many areas of life.

Determination of the level of some heavy metals from medchal lake in Telangana

The aim of this study is to review the research work on concentration of heavy metals in drinking water sources of Medchal Lake. Industrial effluents discharged into the environment, aquatic ecosystem pose a serious threat to our agricultural Products and health. In view of this, levels of some of the heavy metals in Medchal Lake were determined by Atomic Absorption Spectrophotometry. The results obtained show that the mean values of all heavy metals (with the exception of Zn) in water samples from the polluted areas studied were significantly higher than in the control sites, Zn, Pb, Cr, Cu, Ni, Co, Ag, Fe and Mn were determined in water samples collected from Medchal lake. The results for heavy metals analyzed indicated that they are below the limit of admissible concentrations. Although low level of heavy metals was discovered in the lake water and they are within the permissible limits.

Heavy metals biosensor based on defective one-dimensional phononic crystals

In recent years, the detection of water pollution with low levels of heavy metals has attracted the great attention of many researchers as a result of the imminent danger of this type of pollution to all mankind. Meanwhile, we introduce a theoretical approach based on the one-dimensional phononic crystals (1D-PnCs) with a central defect layer as a novel platform for the highly sensitive detection of heavy metal pollution in freshwater. Therefore, the creation of a resonant peak in the transmittance spectrum related to this defect layer is highly conceivable. In this regard, the detection of cadmium chloride (CdCl2) as a dangerous, toxic, and extremely hazardous heavy metal could be investigated based on the small displacement in the position of this resonant peak with the changes in the CdCl2 concentration. Notably, any change in CdCl2 concentration has a direct impact on its acoustic properties. The theoretical framework of our research study is essentially based on the 2 × 2 transfer matrix method and the acoustic properties of the constituent materials as well. The optimization of all sensor parameters represents the mainstay of this study to get the best sensor performance. In this regard, the proposed sensor has a remarkably high sensitivity (S = 1904.25 Hz/ppm) over a concentration range of 0 – 10000 ppm. In addition, the sensor has a high quality factor (QF), and figure of merit of 1771.318, and 73529410−5 (ppm−1), respectively. Finally, we believe this sensor could be a key component of a feasible platform for detecting low concentrations of different heavy metal ions in freshwater.

Ecological and Human Health Risk Assessment of Heavy Metal in Sediment and Demersal Fish Species in Western Offshore Nigeria, Gulf of Guinea

This study was focused to assess the contamination status of heavy metals in sediments, and human health risks associated with fish consumption from western Nigeria offshore in the Gulf of Guinea. Triplicate samples of demersal marine fish species and sediments were collected from five stations (fishing ground) and analysed for heavy metals [mercury (Hg), cadmium (Cd), and lead (Pb)] and metalloid [arsenic (As)] using ICP-OES (inductively coupled plasma optical emission spectrometry) adopted USEPA 200.7 standard method. The metals/metalloid concentrations in demersal fish species and sediment fell below the FAO/WHO permissible limits and sediment quality guidelines (SQG) [probable effect level (PEL) and threshold effect level (TEL)]. The ecological indices [probable contamination index (PCI), mean effect level quotients, newly modified hazard quotient (mHQ), and hazard quotient (HQ)] revealed low contamination level of heavy metals in sediment. The hazard index (HI) of metals in fish species associated with human health fell below the recommended threshold of 1 with no significant health risk to the consumers. The target cancer risk (TCR) of Cd and Pb in the fish species were below the regulation range of 1.0 × 10−6 to 1.0 × 10−4 set by the USEPA. The cluster analysis revealed two clusters. Cluster 1 (C1) showed that Cd was significantly accumulated in the sediment. Cluster 2 (C2) showed significantly low bioaccumulation of Hg, Cd, Pb, and As in fish species across all stations. The ecological and health risk assessment indices generally established low potential adverse effect on demersal marine fish species due to the overall low ecological severity risk associated with heavy metals/metalloids in sediment. Hence, consumers of fisheries resources from western off Nigeria coast are relatively safe from being exposed to any non-carcinogenic and carcinogenic health risk.