Through Holes Research Articles

Analysis and pollution evaluation of heavy metal content in soil of the Yellow River Wetland Reserve in Henan.

This study aims to assess the contamination levels of six heavy metals, namely arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and lead (Pb), in the soil of the Henan Yellow River Wetland Reserve. It seeks to reveal the spatial distribution and trends of heavy metal pollution, providing a scientific basis for the rational utilization and effective protection of soil. Additionally, it aims to propose targeted management and remediation recommendations to mitigate or prevent soil pollution. A total of 706 soil samples were collected in this area in combination with the land use type map. As and Hg were determined by atomic fluorescence spectrometry, and Cr, Cu, Pb and Cd were determined by inductively coupled plasma mass spectrometry. Taking the soil pollution risk screening value of agricultural land (GB15618-2018) as a reference value, the sample data were statistically analyzed, and the Nemerow comprehensive pollution index method combined with ArcGIS technology was used to evaluate the soil environmental quality. The comprehensive pollution index of the soil in the Yellow River Wetland Reserve was 0.42, ranging from 0.17 to 2.38, which was safe and not polluted (I grade). Out of 706 sampling locations, 674 remained uncontaminated, while 26 exhibited cleanliness. Although they were in the warning line, they did not exceed the standard, accounting for 3.68% of the total number of sampling points. Five sample points were slightly polluted, accounting for 0.71% of the total sample points, and one sample point was moderately polluted, accounting for 0.14% of the total sample points. It can be seen that there are few agricultural land pollution points in the Yellow River Wetland Reserve, and the soil environment quality is generally good. The soil in the Yellow River Wetland Reserve in Henan has a very small amount of mild and moderate pollution, and there is no severe pollution. The cleanliness is currently high.

Heavy metal concentrations in surface waters of Hurghada and environs, Red Sea Coast, Egypt, and their correlation with sediment distribution

This study investigates the properties and chemistry of surface water in Hurghada and its adjacent areas, with a focus on assessing the potential impact of human activities on water quality by measuring the concentrations of heavy metals in surface water samples. A total of fifty-nine surface water samples were collected and analyzed for various heavy metals, including manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg), and lead (Pb) using the AAS technique.The results indicate that at the Desert Rose Resort transect, the average total concentrations of heavy metals were within the following ranges: Fe (average of 26.96 μg/L), Cu (average of 0.61 μg/L), Zn (average of 6.31 μg/L), and Pb (average of 0.75 μg/L). Conversely, at the Abu-Shaar transect, Ni (0.87 μg/L) and Cd (average of 0.02 μg/L) were the dominant heavy metals, while Mn exhibited the highest mean value (1.80 μg/L) at the El-Samaka Village transect. Notably, Hg was not detected in any of the samples within the study areas.Comparative analysis of heavy metal concentrations in Hurghada's surface waters with data from the Red Sea coast and other global regions reveals that the study areas maintain heavy metal concentrations well below the maximum permissible values for the marine environment. These findings suggest that human activities have not significantly impacted heavy metal levels in the region's surface waters.Additionally, statistical assessments, such as correlation coefficients (r), were employed to explore the relationships between heavy metal concentrations in water and sediment. These relationships provide valuable insights into the dynamic balance of elements within the sediment and their potential direct or indirect transfer into the water.

Ecological safety of sunflower seeds in the conditions of agricultural intensification

Sunflower cultivation using intensive technologies, which manifests itself in the disruption of crop rotation, high rates of mineral fertilisers and pesticides, leads to an increased risk of products contaminated with heavy metals, nitrates, and pesticide residues. The purpose of this study was to identify the risks of toxic substances accumulation in the soil and sunflower seeds. In this study, the atomic absorption spectrophotometric method was used to determine the content of toxic substances in soil and sunflower seeds. The content of alkaline-hydrolysed nitrogen, mobile phosphorus, exchangeable potassium, the reaction of the soil solution pH, as well as the content of mobile forms of heavy metals: lead, cadmium, copper, zinc, mercury, cobalt, and molybdenum; boron, and radioactive caesium were determined in the soil after sunflower cultivation. The factual content of soil contaminants was compared with their maximum permissible concentrations. The study investigated the content of heavy metals, namely, lead, cadmium, copper, and zinc, as well as nitrates in sunflower seeds. Their content was compared with the values of maximum permissible concentrations. The coefficients of accumulation of the heavy metals under study by sunflower seeds were calculated. Thus, copper and zinc are most intensively absorbed from the soil and accumulate in sunflower seeds, while lead is the least absorbed. The findings suggest that since no excess of the permissible levels of heavy metals and nitrates in sunflower seeds was found, there is a higher probability of their increased accumulation in sunflower by-products: seed husks, stems, leaves, petioles, and roots. The study results can be used in organic sunflower cultivation

Three novel marine species of the genus Reichenbachiella exhibiting degradation of complex polysaccharides.

Three novel strains designated ABR2-5T, BKB1-1T, and WSW4-B4T belonging to the genus Reichenbachiella of the phylum Bacteroidota were isolated from algae and mud samples collected in the West Sea, Korea. All three strains were enriched for genes encoding up to 216 carbohydrate-active enzymes (CAZymes), which participate in the degradation of agar, alginate, carrageenan, laminarin, and starch. The 16S rRNA sequence similarities among the three novel isolates were 94.0%-94.7%, and against all three existing species in the genus Reichenbachiella they were 93.6%-97.2%. The genome sizes of the strains ABR2-5T, BKB1-1T, and WSW4-B4T were 5.5, 4.4, and 5.0 Mb, respectively, and the GC content ranged from 41.1%-42.0%. The average nucleotide identity and the digital DNA-DNA hybridization values of each novel strain within the isolates and all existing species in the genus Reichenbachiella were in a range of 69.2%-75.5% and 17.7-18.9%, respectively, supporting the creation of three new species. The three novel strains exhibited a distinctive fatty acid profile characterized by elevated levels of iso-C15:0 (37.7%-47.4%) and C16:1 ω5c (14.4%-22.9%). Specifically, strain ABR2-5T displayed an additional higher proportion of C16:0 (13.0%). The polar lipids were phosphatidylethanolamine, unidentified lipids, aminolipids, and glycolipids. Menaquinone-7 was identified as the respiratory quinone of the isolates. A comparative genome analysis was performed using the KEGG, RAST, antiSMASH, CRISPRCasFinder, dbCAN, and dbCAN-PUL servers and CRISPRcasIdentifier software. The results revealed that the isolates harbored many key genes involved in central metabolism for the synthesis of essential amino acids and vitamins, hydrolytic enzymes, carotenoid pigments, and antimicrobial compounds. The KEGG analysis showed that the three isolates possessed a complete pathway of dissimilatory nitrate reduction to ammonium (DNRA), which is involved in the conservation of bioavailable nitrogen within the ecosystem. Moreover, all the strains possessed genes that participated in the metabolism of heavy metals, including arsenic, copper, cobalt, ferrous, and manganese. All three isolated strains contain the class 2 type II subtype C1 CRISPR-Cas system in their genomes. The distinguished phenotypic, chemotaxonomic, and genomic characteristics led us to propose that the three strains represent three novel species in the genus Reichenbachiella: R. ulvae sp. nov. (ABR2-5T = KCTC 82990T = JCM 35839T), R. agarivorans sp. nov. (BKB1-1T = KCTC 82964T = JCM 35840T), and R. carrageenanivorans sp. nov. (WSW4-B4T = KCTC 82706T = JCM 35841T).

A strategy for source control of acid mine drainage by intelligent management of mine wastes

For mine site management, the release of acid and heavy metal ions from sulfur-containing waste rock or tailings (principally chalcopyrite and pyrite) under natural deposit conditions is a major environmental problem. In this study, the interaction between chalcopyrite and pyrite at different mass ratios under a simulated acid mine drainage environment was investigated. The dissolution experiments showed that a low proportion of pyrite promotes chalcopyrite dissolution, while a high proportion inhibits dissolution. However, this phenomenon is weakened by the presence of microorganisms. In addition, the combined characterization by X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy indicated that a high ratio of pyrite incorporation facilitated the formation of passivation layers on the chalcopyrite surface. Scanning electron microscopy results show that many oxidation etching pits are found on the surface of the chalcopyrite residues surface in a low ratio of pyrite addition, whereas numerous islands are observed and tightly wrapped around the surface of the chalcopyrite residues surface in a high ratio of pyrite addition. The current work presents a viable, practical approach to tailings stacking that reduces the release of the heavy metal ions copper and acid through the appropriate proportioning of ores.

A Low-Cost Lightweight Deflectometer with an Arduino-Based Signal Interpretation Kit to Evaluate Soil Modulus.

This research presents an innovative solution aimed at addressing the cost and accessibility challenges associated with soil stiffness analysis in construction projects. Traditional lightweight deflectometer (LWD) systems have limitations due to their high cost and proprietary nature, prompting the need for a more widely accessible technology. To fulfill this purpose, a low-cost, open-source LWD onboard sensor signal interpretation system, utilizing Electro-Mechanical and Micro-Electro-Mechanical-System (MEMS) technology-based sensors in conjunction with an Arduino® Uno and ADS1262 Breakout Board, has been developed. This system efficiently processes raw signal data into deflection and force units, enabling precise soil property analysis. Thorough enhancements, calibration, and alignment procedures have been applied and validated through field tests, which have produced highly satisfactory results. By significantly reducing costs while maintaining accuracy, this developed system has the potential to popularize quality control and assurance practices in the construction industry. This open-source approach not only enhances affordability but also broadens accessibility, making soil property analysis more efficient and attainable for a wider range of construction projects.

A flow-directed minimal path sets method for success path planning and performance analysis

Emergency operation plans are indispensable elements for effective process safety management especially when unanticipated events occur under extreme situations. In the paper, a synthesis framework is proposed for the integration success path planning and performance analysis. Within the synthesis framework, success path planning is implemented through flow-directed signal tracing, renaming and reconstruction from a complete collection of Minimal Path Sets (MPSs) that are obtained using graph traversal search on GO-FLOW model diagram. The performance of success paths is then evaluated and prioritized according to the task complexity and probability calculation of MPSs for optimum action plans identification. Finally, an Auxiliary Feed Water System of Pressurized Water Reactor (PWR-AFWS) is taken as an example system to demonstrate the flow-directed MPSs search method for success path planning and performance analysis. It is concluded that the synthesis framework is capable of providing procedural guidance for emergency response and safety management with optimal success path planning under extreme situations.

Addressing Advanced IC Substrate Deformation and Pattern Distortion Using an Extremely Large Exposure Field Fine Fine-Resolution Lithography System

The More than Moore era is upon us, as manufacturers increasingly turn to back-end advances to meet the next-generation device performance gains of today and tomorrow. In the advanced packaging space, heterogeneous integration combines multiple chips with different functionalities and from different silicon nodes inside one package, ranging in size from 75mm x 75mm to 175mm x 175mm. But as with any new technology, heterogeneous integration comes with its own set of unique challenges. For starters, package sizes are expected to grow significantly due to the number of components making up each integrated package. The problem: these significantly larger packages would typically require multiple exposure shots to complete the lithography steps for the package. Furthermore, the process of adding multiple redistribution layers (RDL) may cause stress to both the surface and inside of the substrate. Formation changes experienced by the panel, as a result of thermal, high-pressure and other fan-out processes, shift the design location from its nominal coordinates; this causes inaccurate overlay and low-overlay yield in the lithography process. And then there is the matter of tightening resolution requirements. RDL layers in advanced integrated circuit substrates (AICS) will require a resolution of 3µm and will eventually move toward a resolution of 1µm. To address these challenges, and better enable the heterogenous integration process, an extremely large exposure field, fine-resolution lithography solution was proposed to enable packages over 250mm x 250mm without the need for image stitching, while exceeding the overlay and critical dimension uniformity requirements for these packages. In this paper, a 515mm x 510mm Ajinomoto build-up film (ABF)+copper clad laminate (CCL) substrate is selected as the test vehicle. We will analyze the pattern distortion of an ABF+CCL substrate to understand the distribution of translation, rotation, scale, magnification, trap, orthogonality and other errors in the substrate, and then use an extremely large exposure field, fine-resolution lithography system to address the pattern distortion of the substrate. This demonstration will provide an analysis of panel distortion and detail how the extremely large exposure field, fine-resolution lithography solution addresses panel distortion to achieve an aggressive overlay number.

Low Loss/Low CTE Semiconductor Carrier Packaging Thin Core Material

There is an ever-increasing need by semiconductor/packaging companies for the introduction of a low loss, ultra-low Coefficient of Thermal Expansion chip carrier packaging substrate core material that provides a cost-effective method for producing thin core build up with very dense core vias. This low loss, low CTE flip-chip substrate core is well suited to multi-layer, RF, and applications requiring a system-in-package approach. This paper discusses a novel substrate core material using a build-up film dielectric layer in conjunction with glass fiber weave. Key properties include low loss (Df<0.002), a CTE from 5 - 10 ppm/C, extremely high thermal reliability, and low modulus. An advantage of using glass fiber weave instead of Invar, for instance, is the extremely low CTE that can be achieved while still maintaining a non-conductive power or ground plane. Multilayer circuits using PTFE can suffer from extremely high lamination temperatures, high cost, and low overall yields due to the inability of the soft material to go through a desmear process. Substrate core materials have the primary benefit that they offer stability and increased reliability of many subsequent build-up microvia layers. As monolithic semiconductors are replaced by chiplets, there is a growing need to package many types of chiplets without losing the signal integrity performance of a monolithic semiconductor on a single IC package. An extremely low loss substrate core offers the potential benefit that unique chiplet packaging architectures can be designed with the lowest possible dielectric losses due to the multichip interconnect strategy.

Municipal Wastewater Quality Control: Heavy Metal Comparative Analysis—Case Study

Abstract A comparative analysis was conducted on raw and treated wastewater and the concentrations of heavy metals in sewage sludge from a wastewater treatment plant (WWTP). The research aimed to demonstrate improved efficiency in reducing heavy metal levels as a part of municipal and industrial waste management, with a specific emphasis on minimising the overall environmental impact. In this study, we presented the results of a repeated measures analysis of variance and assessed compliance with heavy metal content standards in sewage sludge from municipal treatment using a one-sample t-test against a reference norm. The analysis included measurements conducted between 2004 and 2015. We conducted an analysis of heavy metals, including zinc (Zn), lead (Pb), cadmium (Cd), copper (Cu), chromium (Cr), and nickel (Ni), manganese (Mn) and mercury (Hg). High Zn concentration that we observed in pre-treatment wastewater raised important questions. Leakages in sewage networks can result in contaminants infiltrating the wastewater, thereby increasing pollutant concentrations. Elevated concentrations can stem from industrial activities, where Zn and pollutants are discharged into wastewater as byproducts of industrial operations. The study illustrated the attainment of the highest sanitary standards, ensuring that treatment processes effectively eliminate harmful toxic substances, ultimately guaranteeing that the final product is safe for further reclamation processes.

Acoustic monitoring humidity effects on the formation of water bridges at sharp contacts

Shear-force Acoustic Near-field Microscopy (SANM) and Whispering Gallery Acoustic Sensing (WGAS) are used to evaluate the role of humidity on the formation and rupture of water meniscus bridges that form between a laterally oscillating tapered probe and a flat substrate. SANM monitors the near-field acoustic wave emitted by the meniscus, while WGAS monitors acoustically the probe’s amplitude of oscillation, as a function of the probe-sample distance. In the instances reported here, the SANM/WGAS measurements are performed in frequency modulation modality, which allows to discriminate the elastic and inelastic components of the probe-fluid-substrate interaction. The response signal traces, acquired when the probe first approaches and then retracts from the sample at 56% relative humidity (or below), revealed absence of hysteresis; this result persists when performing the same experiment a few days later. However, as the humidity increases (different trials from 56% to 67% are included) a notorious hysteresis is observed between the approach and retraction traces. The results indicate that, as the probe approaches the substrate, a higher humidity promotes an increase of stochastic instabilities in the probe-fluid-substrate interactions (reflected in higher damping effects on the probe, and instabilities in the probe-sample distance feedback control). However, the elastic response of the water meniscus prevails over damping effect, as revealed by the greater acoustic emission despite a decrease in the probe’s amplitude. These measurements are relevant to investigations on the dynamic behavior of fluids near hydrophobic/philic substrates, and wetting properties of solids and nanotribology phenomena in general.

Generating AI modules for decoupling capacitor placement using simulation

Abstract. The effects of parameters affecting the input impedance of a power delivery network (PDN) are investigated. It is considered that the size of the power plane and the number of associated planes in the PCB layout, apart from the decoupling capacitor, have an effect on the impedance behavior within a certain frequency range. An artificial neural network (ANN) is trained using the generated data utilizing a process to generate suitable input for training a machine learning (ML) module, which is able to predict the impedance profile of the PDN. In order to obtain a more accurate prediction, Bayesian optimization is implemented and the results are compared to commercial power integrity (PI) software.

Ultra‐high voltage gain DC–DC converter based on new interleaved switched capacitor inductor for renewable energy systems

SummaryIn this paper, introduces a DC–DC converter design based on a modified hybrid switched inductor‐switched capacitor architecture, aimed at achieving ultra‐high voltage gain in renewable energy systems (RES). The proposed converter involves adding a modified boosting conversion mode (MBM) that interleaves with the main switch to double the voltage transfer gain. Additionally, a modified switched capacitor (MSC) technique, utilizing two diodes as interleaved components, is integrated into the main and auxiliary switches to verify low voltage stress across them. In addition, modified hybrid switched inductors with capacitors (MSIC) and diodes are employed to validate ultra‐high voltage gain. The main advantages of the proposed converter are its high efficiency, low voltage stress across diodes and MOSFETs, and the utilization of low values of inductors and capacitors at high switching frequencies. In addition, the voltage stress across the inductors of the (MSIC) is reduced as the duty cycle increases. Furthermore, the current stress on the main switch is reduced when the charge of capacitor C1 becomes zero. Mathematical models for both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) of the proposed converter are explored. Furthermore, a dual PI controller is designed for the proposed converter to maintain a high fixed output voltage. In addition, the PCB design and experimental testing of the proposed converter to verify the simulation and laboratory results. Specifically, the proposed converter is designed to boost up voltage (30–40 V) to a variable output voltage between 200 and 300 V at 300 W at efficiency 96.7%.

Heat transfer enhancement of electronic devices by using flexible printed circuit boards

In this paper, heat transfer in electronic equipment was studied numerically and experimentally, by investing in the flexible printed circuit board and changing the board’s orientation, which is the substrate of the electronic equipment from a vertical to a horizontal position. ANSYS Fluent software has been used to solve the continuity, momentum, and energy equations with the three-dimensional, unsteady, laminar and incompressible flow. In this study, the oscillatory motion equation was used as a boundary condition to represent the motion of the flexible board. In the experimental aspect of this study, a simulation of an ASUS motherboard (X399-A) with dimensions (30 x 25) cm and a Core i9 CPU with a fully working power of 130W was used to study the enhancement of heat transfer in the electronic devices by test rig specially made for this study. The results show that the flexible board’s enhancement in the heat transfer was (7%) vertically and (7.6%) horizontally compared with the rigid board for the same working conditions. The horizontal position is better than the vertical of the two types of rigid and flexible board, with improved heat transfer rates of (2.7%) and (3%); correlation Equations of the Nusselt number from experimental results are presented.

Impact of particle size on heavy metal contamination in human health from sandstorms in Iraq

BackgroundThe Middle East, including Iraq, is undergoing significant climate change, which has accelerated desertification, drought, and dust storms. Rapid industrialization and urbanization, which frequently contaminate the atmosphere with hazardous metals, are to blame for these changes. MethodsThe human health risks of six common heavy metals, including lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu), zinc (Zn), and nickel (Ni), were examined in dust particles that were collected from five major administrative districts in Iraq in order to understand the impact of particle size on heavy metals in a sandy dust storm. The hazard quotient (HQ), hazard index (HI), and carcinogenic risk (RI) were used to evaluate the health risk for both carcinogenic and non-carcinogenic substances. Resultssmaller particles' Cu and Cd concentrations generally increased from 63 μm to 75 μm, and the maximum Cr content was discovered in the particles (75 μm). The HI values of heavy metals were less than 1 and suggested that these elements did not offer a non-cancer risk to either adults or children. TCR values for Ni were higher than 1 × 10−6 in particle size (63 μm, 75 μm, and 200 μm) for children. Moreover, TCR values for Cr were higher than 1 × 10−6 in particle size (63 μm and 200 μm) with the exception that Cr in all sites were higher than TCR 1 × 10−4 in particle size (75 μm) for children ConclusionThe amounts of six metals varied according on the size of the dust storm's particles. Given their health hazard, these metals' health concerns, particularly those of chromium and nickel for children, should receive significant attention.

Identification of time-varying inertia tensor parameters of a space solar power satellite based on a robust weighted recursive algorithm under impulsive disturbance

Considering changes in the structural size and mass caused by the on-orbit assembly process in a planar space solar power satellite, this study proposes an improved robust recursive algorithm to identify the time-varying inertia tensor parameters of the system. In this algorithm, to decrease the effect of impulsive disturbance on inertial parameter identification during the on-orbit assembly and improve computational accuracy, robust weighted factor and multi-innovation theory are involved. Then, the time-varying inertia tensor parameters of this large flexible structure are identified based on the distributed measurement results of multiple attitude sensors. The simulation results indicate that the proposed algorithm improves the identification accuracy and has better robustness than the original method under the impulsive disturbance. The relative values of the average relative error caused by the impulsive disturbance under the proposed algorithm are approximately 27.8–73.0% less than those under the original method. Additionally, the results also demonstrate that the proposed algorithm has higher noise immunity than the classical recursive least-squares method in a time-varying system. When the impulsive disturbance and zero-mean Gaussian white noise are applied to the system, compared with the conventional recursive least-squares method, the proposed algorithm yields lower absolute and relative values of the average relative error by approximately 4.2% and 44.9%, respectively.

High-quality and efficient large-area copper removal utilizing laser-induced active mechanical peeling

Large-area copper layer removal is one of the essential processes in manufacturing printed circuit boards (PCB) and frequency selective surfaces (FSS). However, laser direct ablation (LDA) with one-step scanning is challenging in resolving excessive substrate damage and material residue. Here, this study proposes a laser scanning strategy based on the laser-induced active mechanical peeling (LIAMP) effect generated by resin decomposition. This scanning strategy allows the removal of large-area copper layers from FR-4 copper-clad laminates (FR-4 CCL) in one-step scanning without additional manual intervention. During the removal process, the resin decomposition in the laser-irradiated area provides the mechanical tearing force, while the resin decomposition in the laser-unirradiated area reduces the interfacial adhesion force and provides recoil pressure. By optimizing scanning parameters to control the laser energy deposition, the substrate damage and copper residue can be effectively avoided. In our work, the maximum removal efficiency with different energy densities, pulse duration, and repetition frequency are 31.8 mm2/ms, 30.25 mm2/ms, and 82.8 mm2/ms, respectively. Compared with the reported copper removal using laser direct write lithography technology combined with wet chemical etching (LDWL+WCE) and LDA, the efficiency improved by 8.3 times and 66 times. Predictably, the laser scanning strategy and the peeling mechanism are simple and controllable, which have potential in electronics, communications, and aerospace.

Investigation of Sediment Pollution in the Gulf of Elefsina Using Environmental Indicators

In this paper, the sediment pollution in the Gulf of Elefsina, over the period 1986-2010, has been measured and presented. The pollution had been measured regarding heavy metals, like cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn). Initially, the measured area is presented, along with the sources of pollution in the historical background and the wider region. Three pollutant indicators had been calculated for the investigation of Sediment Pollution: The Pollution Load Index (PLI), the Enrichment Factor (EF) and the Geo-accumulation index (Igeo). The results of the Pollution Control and Environmental Quality Office measurements had been used for the calculation of these indicators, taken at six locations of the coast and three locations in the center of the Gulf of Elefsina. The study of these indicators reveals that there is heavy metal pollution at all sampling locations, while the most heavily affected areas of the Gulf are these near Skaramangas Shipyards and Elefsis Shipyards. More intense pollution is recorded for Cd, Cu, Fe, Pb, Zn. More specifically, high values of Cd had been measured at all sampling points, while for Cu, Fe, Pb and Zn high values had been measured in areas that are active in shipbuilding-repair and dismantling units. In contrast, there is no pollution for Mn.

Determination of Heavy Metals in Municipal Water Network of Tehran, Iran: A Health Risk Assessment with a Focus on Carcinogenicity

Background: Several contaminants such as trace elements can pollute drinking water sources with subsequent toxic effects on humans. These compounds may also accumulate in target organs and result in carcinogenic reactions. Objectives: The concentrations of heavy metals, including arsenic (As), nickel (Ni), zinc (Zn), aluminum (Al), copper (1), cobalt (Co), lead (Pb), cadmium (Cd), iron (Cd), tin (2), antimony (Sb), chromium (3), and mercury (Hg) were aimed to determine in the drinking water of Tehran, Iran and to assess the carcinogenic and non-carcinogenic risk for consumers. Methods: A total of 66 tap water samples were collected from 22 regions of Tehran and their heavy metal contents were measured by inductively coupled plasma mass spectrometry (ICP-MS). The non-carcinogenic and carcinogenic health risks were calculated, using hazard quotient (HQ) and incremental lifetime cancer risk (ILCR), respectively. Results: The findings revealed that the mean concentrations of measured elements were lower than the maximum permissible limits established by Iranian National Standards, United States Environmental Protection Agency (USEPA), and the World Health Organization (WHO). HQ was less than 1 for all metals except Cr and ILCR was higher than 1× 10-4 for Cr and Cd, which may cause human health risk. Conclusions: No carcinogenic effects were posed by heavy metals contamination in the drinking water of Tehran; however, the content of Cr and Cd may cause human health risks because of the high daily intake of tap water throughout the lifetime and the tendency of these metals to accumulate in the human body organs. Therefore, implementing ongoing programs to monitor heavy metals in municipal drinking water and applying appropriate corrective actions to prevent the transfer of these pollutants to drinking water is crucial.

Heavy Metal Pollution in a Lake: An Assessment of the Ecological Threat

The purpose of this study was to investigate and evaluate the presence of different heavy metals in sediment samples collected from water of Durgam Cheruvu . The concentrations of six heavy metals, namely arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn), were quantified using the technique of inductively coupled plasma-atomic emission spectroscopy (ICPAES). The investigation employed relative enrichment factors and prospective ecological risk indices to examine the contamination levels of heavy metals in sediment samples and evaluate their potential ecological impact on the surrounding ecosystem. The order of heavy metal sediment enrichment factors was determined to be as follows: chromium (Cr) exhibited the highest enrichment factor, followed by arsenic (As), cadmium (Cd), zinc (Zn), copper (Cu), and lead (Pb). Several potential ecological risk indices for heavy metals were identified. The order of decreasing reactivity of the elements is as follows: Cadmium (Cd) > Arsenic (As) > Chromium (Cr) > Copper (Cu) > Lead (Pb) > Zinc (Zn). The prospective ecological risk indices, as determined through calculations, indicate that the lake has been low contaminated by heavy metals. Cadmium (Cd) exhibited a moderate level of potential ecological risk within the ecological environment and emerged as the primary factor contributing to the possible toxicity response indices associated with different heavy metals in Durgam cheruvu. The application of analysis of variance was employed to determine the statistical significance of the observed fluctuations in heavy metal concentrations. The analysis of mean seasonal concentrations of metals revealed statistically significant variations across different seasons and sampling sites. The pollution in Durgam Cheruvu may be attributed to industrial and anthropogenic activity. We have put up a series of techniques that can be implemented to mitigate the accumulation of heavy metals in the lake.