Heavy Metals Research Articles

Effects of microplastics on microbial community structure and wheatgrass traits in Pb-contaminated riparian sediments under flood-drainage-planting conditions

The coexistence of microplastics (MPs) and heavy metals in sediments has caused a potential threat to sediment biota. However, differences in the effects of MPs and heavy metals on microbes and plants in sediments under different sediment conditions remain unclear. Hence, we investigated the influence of polyethylene (PE) and polylactic acid (PLA) MPs on microbial community structure, Pb bioavailability, and wheatgrass traits under sequential incubation of sediments (i.e., flood, drainage, and planting stages). Results showed that the sediment enzyme activities presented a dose-dependent effect of MPs. Besides, 10% PLA MPs significantly increased the F1 fractions in three stages by 11.13%, 30.10%, and 17.26%, respectively, thus resulting in higher Pb mobility and biotoxicity. MPs altered sediment bacterial composition and structures, and bacterial community differences were evident in different incubation stages. Moreover, the co-exposure of PLA MPs and Pb significantly decreased the shoot length and total biomass of wheatgrass and correspondingly activated the antioxidant enzyme activity. Further correlation analysis demonstrated that community structure induced by MPs was mainly driven by sediment enzyme activity. This study contributes to elucidating the combined effects of MPs and heavy metals on sediment ecosystems under different sediment conditions.

Competitive adsorption of heavy metals onto xanthate-modified sludge hydrochar and its solidification as secondary minerals

In this study, a sulfur-modified magnetic hydrochar was synthesized by grafting thiol-containing groups onto the sludge-derived hydrochar. The modified hydrochar exhibited effective adsorption of Cu2+, Pb2+, Zn2+, and Cd2+ over a wide pH range and in the presence of coexisting ions, and showed almost no secondary leaching in three acidic solutions. In the mult-metal ion system, the modified hydrochar exhibited maximum adsorption capacities were 39.38, 105.74, 26.53, and 38.11 mg g−1 for Cu2+, Pb2+, Zn2+, and Cd2+, respectively. However, the binding capacity and adsorption amount of modified hydrochar for metal ions were lower in the mult-metal ion system compared to the unit-metal ion system. Notably, Pb2+ showed a strong inhibitory effect on the adsorption of other heavy metal ions by modified hydrochar due to strong competition for xanthate functional groups. The Pb2+ occupied the xanthate and native functional groups (–OH, –NH2, and Fe–O etc.), leaving only a small amount of adsorption sites for Cu2+, Zn2+ and Cd2+. Simulation results further supported these findings, indicating that Pb2+ had the highest density profiles near the four functional groups, and the density profiles of the four heavy metals near the xanthate functional groups were greater compared to the other three functional groups. Furthermore, the SEM-EDS, TOF-SIMI, and XPS results indicated that modified hydrochar achieved excellent mineral binding mainly through electrostatic interaction, ion exchange, and chelation. Overall, these results highlight the sulfur-modified magnetic hydrochar as a highly efficient adsorbent for heavy metals in environmental applications.

Exploring the potential of sustainable use of reclaimed water to improve crop production in response to contaminants in Vigna radiata

An efficient method of managing agricultural resources is to reuse wastewater for crop irrigation and fertilization. Irrigation using reclaimed water after treatment can have both beneficial and bad environmental effects. The national water strategy of Saudi Arabia considers reclaimed wastewater as an essential component of Saudi Arabia's water resource. It targets to decrease the load of desalination from the Red Sea and use it as a major source of agriculture and industrial use. In Vigna radiata, an experiment is carried out to determine the level of dilution for agricultural application in a seed germination experiment in response to contaminants. The physicochemical properties such as pH, ammonia, turbidity, and chloride values of reclaimed water were higher as compared to the standard guidelines of KSA for using irrigation water. Further, all the studied parameter concentrations decreased with the dilution of tap water. In the seed germination experiment,% germination, relative seed germination, seedling vigor index, etc. were calculated as compared to the control. The results infer that the application of 30 % reclaimed water (T2) enhanced the germination percentage, relative seed germination, and seedling vigor index of V. radiata. The growth of root, shoot, relative shoot growth, fresh weight, and dry weight of seedlings showed that T5 and T6 treatments are not suitable for Vigna cultivation as compared to the control. However, the results suggested that dilution of reclaimed water decreases the concentrations of potential contaminants of emerging concern, heavy metals, pesticides, etc., and makes the water suitable for irrigation.

Impact of organic matter molecular weight on hexavalent chromium enrichment in green microalgae

In lightly polluted water containing heavy metals, organic matter, and green microalgae, the molecular weight of organic matter may influence both the growth of green microalgae and the concentration of heavy metals. This study elucidates the effects and mechanisms by which different molecular weight fractions of fulvic acid (FA), a model dissolved organic matter component, facilitate the bioaccumulation of hexavalent chromium (Cr(VI)) in a typical green alga, Chlorella vulgaris. Findings show that the addition of FA fractions with molecular weights greater than 10kDa significantly enhances the enrichment of total chromium and Cr(VI) in algal cells, reaching 21.58%-31.09% and 16.17%-22.63%, respectively. Conversely, the efficiency of chromium enrichment in algal cells was found to decrease with decreasing molecular weight of FA. FA molecular weight within the range of 0.22 μm-30 kDa facilitated chromium enrichment primarily through the algal organic matter (AOM) pathway, with minor contributions from the algal cell proliferation and extracellular polymeric substances (EPS) pathways. However, with decreasing FA molecular weight, the AOM and EPS pathways become less prominent, whereas the algal cell proliferation pathway becomes dominant. These findings provide new insights into the mechanism of chromium enrichment in green algae enhanced by medium molecular weight FA. Environmental implicationHexavalent chromium (Cr(VI)) presents a notable hazard in water environments due to its toxicity, even at low concentrations. In water with slight pollution levels containing dissolved organic matter (DOM), Cr(VI), and green microalgae, the molecular weights of DOM play a crucial role in Cr(VI) bioaccumulation in microalgae cells. However, the precise mechanisms underlying this process remain poorly understood. This study established a ternary system consisting of "Chlorella-DOM fractions-Cr(VI)" to investigate how medium molecular weight DOM enhances Cr(VI) enrichment in Chlorella, providing insight into the regulatory role of organic matter in the enrichment of heavy metals in green algae.

Microbial Application in Heavy Metal Removal from Pharmacological Industrial Effluent

In industrial effluents, significant amounts of metallic cations such as zinc, copper, iron, manganese, lead, nickel, and cadmium are present. Long-term irrigation with these effluents increases the amount of organic carbon and heavy metals in the soil, increasing the likelihood that they will enter the food chain and, eventually, result in significant bioaccumulation. Many techniques for the treatment and disposal of metal-containing wastes, such as ion exchange, reverse osmosis, in flotation, and evaporation, have been developed in order to reduce metal pollution issues. The main disadvantages of conventional treatments are low efficiency at low concentrations of heavy metals, expensive handling, and safe disposal of toxic sludge. In light of this, an effort has been made to investigate how tannery affects the growth of green gram.

Melatonin foliar application promoted anthocyanin accumulation boosted reactive oxygen scavenging by upregulating the key enzymes activities and genes expression of anthocyanin biosynthesis pathway in green and purple mustard under vanadium stress

Heavy metal vanadium (V) is poisonous to both plants and animals. Plant resistance to heavy metals stress can be conferred by the multifunctional signaling molecule melatonin, although the underlying mechanisms are still largely understood. We elucidated the significant contribution of the secondary metabolite anthocyanin to the enhancement of V stress tolerance by melatonin in both green and purple mustard genotypes. The effects of excessive V were leaf yellowing, slowed development, decreased photosynthetic activity, and an increase in the buildup of reactive oxygen species and malondialdehyde in both mustard genotypes. It interesting to note that during V stress, key anthocyanin biosynthetic pathway enzymes activities and leaf anthocyanin concentration increased while exogenous melatonin applied as foliar further boosted activities of key anthocyanin biosynthetic pathway enzymes and leaf anthocyanin concentration in both green and purple mustards. Furthermore, the application of exogenous melatonin increased the levels of endogenous melatonin and mitigated V toxicity. Conversely, the suppression of melatonin intensified V-induced phytotoxicity and delayed the accumulation of anthocyanin by downregulating the transcript levels of essential structural genes. Under V stress conditions, the genes expression related to anthocyanin production, antioxidant enzymes activities, and stress resistance was significantly higher in purple mustard than green mustard genotype. Additionally, melatonin decreased V deposition in roots and leaves. The results recommended that melatonin foliar application to mustard plants inhibited the availability of V to plant and promote V stress tolerance.

Veterinary antibiotics and metals impact the mass, composition and hydrolysis of biomass cultivated in piggery wastewater treatment photobioreactors

Photobioreactors are a promising alternative for piggery wastewater treatment which allows to produce valuable biomass, but the presence of antibiotics or heavy metals in the pig manure can influence the biomass composition and the posterior valorization processes. This study evaluates the effect of these pollutants on mass, composition and hydrolysis yields of the consortia of microalgae and bacteria obtained in a 1,280L photobioreactor treating pig manure. The photobioreactor feed was doped with 1) veterinary antibiotics; 2) copper, zinc, and arsenic; and 3) combination of both pollutants. The pollutants presence decreased the mass of biomass grown in the photobioreactor by up to 35% while glucose content of the biomass by up to 42% and increased protein and xylose by 30% and 16% due to oxidative stress. Likewise, they increased the protein solubilization yield by acid hydrolysis at 120 ºC by 32% while reduced glucose solubilization by 49% after alkaline hydrolysis at 120 ºC. Applying enzymatic hydrolysis and ultrasound assisted enzymatic extractions, glucose and xylose recoveries were drastically reduced in presence of heavy metals (~100%). Antibiotics increased xylose solubilization by ultrasonication (74%), but also its degradation, decreasing xylose recovery. Thus, the presence of all these pollutants in pig manure affected biomass production and valorization and these results must be considered for biorefinery processes.

Comparative Assessment of the Content of Heavy Metals in the Ash of Solid Fuel Pellets and Different Types of Sorted and Unsorted Solid Domestic Waste

Comparative Assessment of the Content of Heavy Metals in the Ash of Solid Fuel Pellets and Different Types of Sorted and Unsorted Solid Domestic Waste

Green synthesis of NiO nanoparticles using a Cd hyperaccumulator (Lactuca sativa L.) and its application as a Pb(II) and Cu(II) adsorbent

The proliferation of heavy metal contamination, namely, lead and copper, has emerged as a pervasive worldwide peril to human existence. One potential solution for addressing this issue is the utilization of nanoparticle adsorption, specifically for nickel oxide nanoparticles. However, to promote environmental sustainability, scholarly studies have identified green synthesis as a prospective methodology. The process of cadmium phytoremediation, although offering a potential remedy for heavy metal contamination, gives rise to apprehensions surrounding the proper disposal of cadmium hyperaccumulator plant biomass. Hence, it is imperative to establish suitable strategies for the disposition or usage of this biomass. The utilization of hyperaccumulator extracts for the eco-friendly production of nickel oxide nanoparticles remains unexplored in the current literature. The main aim of this research is to explore the possible application of Lactuca sativa L. as a plant species with the ability to accumulate high levels of cadmium. The study also seeks to examine the efficacy of utilizing these plants in the fabrication of nickel oxide nanoparticles and evaluate their capacity to absorb lead and copper ions. The characterization of nickel oxide nanoparticles is conducted through a range of techniques, encompassing scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller spectroscopy, and vibrating sample magnetometry. The present work achieved successful utilization of Lactuca sativa L. extract for the manufacture of nickel oxide nanoparticles, which showed notable efficacy as an adsorbent for lead and copper. The synthesis of nickel oxide nanoparticles using an extract from Lactuca sativa L. has demonstrated the viability of utilizing hyperaccumulator biomass in the phytoremediation of cadmium. This finding presents a promising avenue for investigating hyperaccumulator plants as potential sources for nanoparticle synthesis in the field of environment-based nanotechnology development.

Transporters and phytohormones analysis reveals differential regulation of ryegrass (Lolium perenne L.) in response to cadmium and arsenic stresses

Cadmium (Cd) and arsenic (As) are two highly toxic heavy metals and metalloids that coexist in many situations posing severe threats to plants. Our investigation was conducted to explore the different regulatory mechanisms of ryegrass (Lolium perenne L.) responding to individual and combined Cd and As stresses in hydroponics. Results showed that the ryegrass well-growth phenotype was affected by Cd stress of 10mg·L-1. However, As of 10mg·L-1 caused rapid water loss, proline surge, and chlorosis in shoots, suggesting that ryegrass was highly sensitive to As. Transcriptomic analysis revealed that the transcription factor LpIRO2 mediated the upregulation of ZIP1 and YSL6 that played an important role in Cd tolerance. We found that the presence of As caused the overexpression of LpSWT12, a process potentially regulated by bHLH14, to mitigate hyperosmolarity. Indoleacetic acid (IAA) and abscisic acid (ABA) contents and expression of their signaling-related genes were significantly affected by As stress rather than Cd. We predict a regulatory network to illustrate the interaction between transporters, transcription factors, and signaling transduction, and explain the antagonism of Cd and As toxicity. This present work provides a research basis for plant protection from Cd and As pollution. Environmental implicationCd and As are two highly toxic heavy metals and metalloids that coexist in many situations resulting in plant uptake, and then threaten humans through the food chain. Ryegrass is a popular cool-season forage, yet its comprehensively responsive mechanisms under individual and combined Cd and As stresses are poorly studied. Herein, physiological and transcriptomic analysis reveals that ryegrass exhibits efficient adaptation to Cd, and high sensitivity to As, which are associated with their respective responsive transporters and hormone signaling mediated by transcription factors. Our results provide a theoretical basis for alleviating Cd and As co-contamination of plants.

Novel fluorescent sensor based on triazole-pyridine derivative for selective detection of mercury (II) ions in different real water samples: Experimental and DFT calculations

Toxic heavy metals, particularly mercury II ions, must be selectively detected in industrial effluent to restrict their percentage and thereby aid in environmental protection. The present study describes the synthesis of 6-(4-(4-(5-cyano-6-oxo-4-styryl)-1,6-dihydropyridin-2-yl)-5-methyl-1H-1,2,3-triazol-1-yl)phenyl)-2-oxo-4-styryl)-1,2-dihydropyridine-3-carbonitrile (TOHC) and its ability as a novel selective fluorescent probe for the detection of mercury II ions in different real water samples. The structure of the prepared TOHC was confirmed by both FTIR and 1HNMR analysis, while crystal structure and thermal stability was investigated using XRD and TGA techniques. The optical properties of TOHC were investigated using both UV–vis and fluorescence spectroscopy at different pH values. Its luminescent properties obtained when TOHC is excited by a wavelength equal to 424 nm, where a maximum emission peak has observed at a wavelength equal to 466.6 nm. Moreover, using Stern-Volmer equation indicate that there is a good correlation between the concentration of Hg2+ ions and the fluorescence intensity of TOHC accompanied with high quenching rate equal to 2.24 x 104 mol−1.L. Selectivity of TOHC toward Hg2+ ions was confirmed by the assistance of fifteen different metal cations. In addition, Job’s Plot method and UV–vis spectroscopy were used to estimate the stoichiometry as well as understand the quenching mechanism between TOHC sensor and Hg2+ ions. The applicability of TOHC sensor for the detection of Hg2+ ions in real samples was further validated using five different real water samples and exhibited excellent results. Lastly, DFT calculations were conducted to provide atomistic insights into the chemical interaction between Hg(II) and TOHC.

Phosphate-solubilizing bacteria improve the antioxidant enzyme activity of Potamogeton crispus L. and enhance the remediation effect on Cd-contaminated sediment

Phosphorus-solubilizing bacteria (PSB) assisted phytoremediation of cadmium (Cd) pollution is an effective method, but the mechanism of PSB-enhanced in-situ remediation of Cd contaminated sediment by submerged plants is still rare. In this study, PSB (Leclercia adecarboxylata L1-5) was inoculated in the rhizosphere of Potamogeton crispus L. (P. crispus) to explore the effect of PSB on phytoremediation. The results showed that the inoculation of PSB effectively improved the Cd extraction by P. crispus under different Cd pollution and the Cd content in the aboveground and underground parts of P. crispus all increased. The μ-XRF images showed that most of the Cd was enriched in the roots of P. crispus. PSB especially showed positive effects on root development and chlorophyll synthesis. The root length of P. crispus increased by 51.7%, 80.5% and 74.2% under different Cd pollution, and the Ca/Cb increased by 38.9%, 15.2% and 8.6%, respectively. Furthermore, PSB enhanced the tolerance of P. crispus to Cd. The contents of soluble protein, MDA and H2O2 in 5mg·kg-1 and 7mg·kg-1 Cd content groups were decreased and the activities of antioxidant enzymes were increased after adding PSB. The results showed that the application of PSB was beneficial to the in-situ remediation of submerged plants. Environment implicationHeavy metal pollution in sediment has a potential threat to the quality of water environment, and it is necessary to repair it. In-situ extraction of submerged plants is a green, low-cost and sustainable technology, but this technology has the problem of low plant biomass.In this study, a method of phosphate-solubilizing bacteria combined with submerged plant restoration was proposed, and the factors of phosphate-solubilizing bacteria promoting the growth of submerged plants and enhancing cadmium tolerance were analyzed. It provides a new idea for in-situ remediation of heavy metal pollution in sediment.

Physio-biochemical Behavior and Health Effects of Pepper Plants Subjected to Lead Stress and Their Responses to Remediating Agents as Microbial Activity and Phosphorus

This work assessed the alleviating effects of bacteria (Bacillus subtilis) and phosphorus as environmentally friendly materials on the cultivation of pepper plants in polluted soil with lead (Pb) in forms of PbSO4, and Pb(NO3)2 at rates of 0, 1000, 2000 and 3000 µg Pb/g soil. Pot experiments were conducted to study the growth parameters, some physiological factors, biochemical constituents, and yield attributes, as well as the tolerance index (TI), translocation factor (TF), bioconcentration factor (BCF), and health effects [daily intake of heavy metals (DIM), health risk index (HRI), and carcinogenic risk (CR)]. Increasing the Pb concentration of all Pb salt used in soil severely affected the plant vegetative growth parameters. In comparison with other Pb salt forms, Pb(NO3)2 salt had a strong inhibitory impact. Additionally, the photosynthetic pigments in leaves were negatively impacted by all Pb salt forms. The application of Pb in all salt forms led to changes in the leaf water deficit (LWD), osmotic pressure, and membrane integrity and decreased the total water content, relative water content (RWC), transpiration rate, and leaf succulence. Pollution with Pb salts considerably decreased the yield constituents and various chemical properties of pepper, more so in the presence of Pb nitrate than in the presence of Pb sulfate type. A comparison of the concentration of Pb presence of Pb nitrate was greatly increased than the Pb sulfate in the whole plants. The safe limit of 0.3 mg/kg was exceeded by the Pb concentration in pepper fruits (6.3 and 4.3 mg/kg) cultivated in Pb-contaminated soil [with Pb(NO3)2 and PbSO4, respectively]. Additionally, Pb sulfate had a greater detrimental effect on Pb uptake in several plant organs than other Pb salt forms. The TI of pepper plants treated with salt types was >60% with PbSO4 (75.6%), whereas it was <60% with Pb(NO3)2 (35.2%). The BCF values of pepper plants in the polluted Pb soils varied from 0.10 to 0.41, indicating a moderate accumulator plant. At every level of Pb contamination with all Pb salt types, the sequence of Pb TF values was as follows: roots (TFr) > shoots (TFsh) > fruits (TFf), with TF values < 1. When compared with TFr and TFsh, TFs for shoot to fruits (TFf) had the lowest values (range, 0.07–0.22). The DIM, HRI, and CR values of pepper plants revealed that the Pb of fruit of stressed pepper plants is within safe limits. In addition to reducing the detrimental effects of intolerable Pb levels (2000 and 3000 µg Pb/g soil) on the majority of the aforementioned characters, adding Bacillus bacteria as a bio-agent and phosphorus as a chemo-agent to Pb-polluted soils also stimulated growth, increased yield, controlled plant water relations, protected photosynthetic pigments, and sharply decreased the Pb accumulation in plant organs. The Bacillus bacteria application resulted in some superior characteristics, such as root length, leaf number, leaf length, leaf area, leaf area index, fresh biomass, dry biomass, photosynthetic pigments, quantity yield attributes, reduction Pb accumulation in all plant organs, TI, TFr, TFf, BCF, in health effects trials, whereas phosphorus application improved plant height, leaf width, RWC, LWD, osmotic pressure, total soluble solids, acidity, total carbohydrates, total protein, and TFsh.

The Effect of Heavy Metal Speciation on Arbuscular Mycorrhizal Fungi Associated with <i>Phoenix dactylifera</i> L. Growing in Moroccan Urban and Peri-Urban Environments

The Effect of Heavy Metal Speciation on Arbuscular Mycorrhizal Fungi Associated with <i>Phoenix dactylifera</i> L. Growing in Moroccan Urban and Peri-Urban Environments

Fluorescent carbon dots crosslinked Salix psammophila microcrystalline cellulose interpenetrating hydrogel system for sensitive detection and efficient adsorption of Fe3+

To combat the contaminating effects of heavy-metal ions on water resources, we prepared blue photonitrogen-doped carbon quantum dots (NCDs) from Salix psammophila (SP) as a raw material, doped them into a microcrystalline cellulose hydrogel, and successfully created a composite hydrogel (NCDs-SP-MCC-gels) for concurrent fluorescence detection and Fe3+ adsorption. The NCDs-SP-MCC-gels was examined for their shape, chemical composition, fluorescence characteristics, and adsorption behaviors. Results demonstrated that the NCDs-SP-MCC-gels displayed a broad linear range of Fe3+ fluorescence response (200–1000 mg/L; detection limit = 3.90583 mg/L) and a high adsorption capacity for Fe3+ (610 mg/g). The adsorption data fitted the Langmuir and pseudo-second-order models well. Further research was conducted on Fe3+ detection and adsorption onto the NCDs-SP-MCC-gels. This study proposes a green and sustainable way to create a material for the detection and absorption of heavy-metal ions.

A GIS-based analysis of heavy metals around Otukpo rice mill in Benue state

Heavy metals are primarily sourced from natural pedo-geochemical backgrounds and anthropogenic occurrences like composting, sewage sludge, aerosol deposition, and waste animal manure. The study aims to determine the heavy metals within the rice mill in Otukpo to understand the spatial distribution with the objectives to examine the heavy metals within the identified activity areas in the Otukpo rice mill, to determine the spatial distribution of heavy metals within the study area and to compare heavy metal values with the acceptable limits. Soil samples were collected from ten locations at Otukpo Rice Mill to analyze heavy metal concentrations. The samples were collected using sterile bottles and a stainless trowel, and the soil samples were analyzed for the concentrations of Cadmium, Copper, Lead, Nickel, Zinc, Mercury, Iron, Arsenic, and Chromium using the Atomic Absorption Spectrophotometry method. The result was analyzed using interpolation to see the variation of the Heavy metals within the various activity areas. The result of the study reveals that Iron has the highest concentration at the Entrance point and lowest at the Generator house with a range value of 3.92 – 1.12mg/kg respectively. The highest concentration of Zinc was recorded at the Mechanic workshop while the lowest is at the Drying point with a range value of 0.135 – 0.872mg/kg respectively. The Husk dumpsite recorded the highest concentration of Copper (0.666mg/kg) with the Drying point recording the least (0.088 mg/kg). The study reveals uneven concentrations and highlights the effectiveness of the Geographic Information System in mapping heavy metal concentrations.

Environmental and living organisms’ disaster caused by discharge of drilling fluid waste

The oil and gas industry plays a vast and vital role in our society. Despite the numerous benefits of the production of crude oil, its activities pose a lot of dangers to the environment and living organisms because it generates a huge volume of solid and liquid wastes, thus, these wastes require treatment before disposal. The major drilling wastes are drilling muds, drilling cuttings, and obnoxious gas emissions. Parameters that should be considered during the disposal of decontaminated drilling muds and drill cuttings are heavy metals. These wastes are introduced into the environment through accidental spills as well as intentional discharge. The discharge into the environment has effects on humans, plants, birds, soil, and also aquatic life. Generally, oil based drilling fluid usage and disposal are not preferable. However, water based drilling fluid and synthetic based drilling fluid can be a technically and economically disposed because they are biodegradable. Generally, drilling waste disposal options are offshore disposal, onshore disposal and drill cuttings re-injection. Zero discharge can achieved by drill cuttings re-injection. However extensive study must be carried before drill cuttings can be re-inject to the formation. Disposal options must be evaluated based on economics, environment and operational aspects. This study aimed at evaluating the heavy metals present in the drilling fluid waste and drilling cuttings. The experiment was achieved with the aid of a Flame Atomic Absorption Spectrophotometer (FAAS). Upon the investigation, it was discovered that lead concentration in drilling cuttings was the highest with the concentration of 1,058.9 mg/l and drilling fluid was 190.3 mg/l whereas NUPRC limit is 5 mg/l; the total chromium concentration in drilling cuttings was 19.16 mg/l and drilling fluid was 8.38 mg/l whereas NUPRC limit is 8 mg/l; zinc was 58.10 mg/l in drilling cuttings while in drilling fluid it was 23.96 mg/l whereas NUPRC limit is 50 mg/l; silver concentration in drilling cuttings was 14.67 mg/l and drilling fluid 0.91 mg/l whereas NUPRC limit is 5 mg/l; Cadmium concentration in drilling cuttings was 2.17 mg/l and drilling fluid was 1.36 mg/l whereas NUPRC limit is 1 mg/l. In no doubt. The study has shown that disposal of this drilling fluid waste and drilling cutting directly into the environment without treatment will be detrimental to the living organisms and therefore should be discouraged.

Heavy metal sequestration from wastewater by metal-organic frameworks: a state-of-the-art review of recent progress.

Metal-organic frameworks (MOFs) have emerged as highly promising adsorbents for removing heavy metals from wastewater due to their tunable structures, high surface areas, and exceptional adsorption capacities. This review meticulously examines and summarizes recent advancements in producing and utilizing MOF-based adsorbents for sequestering heavy metal ions from water. It begins by outlining and contrasting commonly employed methods for synthesizing MOFs, such as solvothermal, microwave, electrochemical, ultrasonic, and mechanochemical. Rather than delving into the specifics of adsorption process parameters, the focus shifts to analyzing the adsorption capabilities and underlying mechanisms against critical metal(loid) ions like chromium, arsenic, lead, cadmium, and mercury under various environmental conditions. Additionally, this article discusses strategies to optimize MOF performance, scale-up production, and address environmental implications. The comprehensive review aims to enhance the understanding of MOF-based adsorption for heavy metal remediation and stimulate further research in this critical field. In brief, this review article presents a comprehensive overview of the contemporary information on MOFs as an effective adsorbent and the challenges being faced by these adsorbents for heavy metal mitigation (including stability, cost, environmental issues, and optimization), targeting to develop a vital reference for future MOF research.

Risk of heavy metal(loid) compositions in fine particulate matter on acute cardiovascular mortality: a poisson analysis in Anyang, China.

Fine particulate matter (PM2.5) is a risk factor of cardiovascular disease. Associations between PM2.5 compositions and cardiovascular disease are a point of special interest but inconsistent. This study aimed to explore the cardiovascular effects of heavy metal(loid) compositions in PM2.5. Data for mortality, air pollutants and meteorological factors in Anyang, China from 2017 to 2021 were collected. Heavy metal(loid) in PM2.5 were monitored and examined monthly. A Case-crossover design was applied to the estimated data set. The interquartile range increase in cadmium (Cd), antimony (Sb) and arsenic (As) at lag 1 was associated with increment of 8.1% (95% CI: 3.3, 13.2), 4.8% (95% CI: 0.2, 9.5) and 3.5% (95% CI: 1.1, 6.0) cardiovascular mortality. Selenium in lag 2 was inversely associated with cerebrovascular mortality (RR = 0.920 95% CI: 0.862, 0.983). Current-day exposure of aluminum was positively associated with mortality from ischemic heart disease (RR = 1.083 95% CI: 1.001, 1.172). Stratified analysis indicated sex, age and season modified the cardiovascular effects of As (P < 0.05). Our study reveals that heavy metal(loid) play key roles in adverse effects of PM2.5. Cd, Sb and As were significant risk factors of cardiovascular mortality. These findings have potential implications for accurate air pollutants control and management to improve public health benefits.

Assessing metal(loid)s-Induced long-term spatiotemporal health risks in Coastal Regions, Bay of Bengal: A chemometric study.

Despite sporadic and irregular studies on heavy metal(loid)s health risks in water, fish, and soil in the coastal areas of the Bay of Bengal, no chemometric approaches have been applied to assess the human health risks comprehensively. This review aims to employ chemometric analysis to evaluate the long-term spatiotemporal health risks of metal(loid)s e.g., Fe, Mn, Zn, Cd, As, Cr, Pb, Cu, and Ni in coastal water, fish, and soils from 2003 to 2023. Across coastal parts, studies on metal(loid)s were distributed with 40% in the southeast, 28% in the south-central, and 32% in the southwest regions. The southeastern area exhibited the highest contamination levels, primarily due to elevated Zn content (156.8 to 147.2 mg/L for Mn in water, 15.3 to 13.2 mg/kg for Cu in fish, and 50.6 to 46.4 mg/kg for Ni in soil), except for a few sites in the south-central region. Health risks associated with the ingestion of Fe, As, and Cd (water), Ni, Cr, and Pb (fish), and Cd, Cr, and Pb (soil) were identified, with non-carcinogenic risks existing exclusively through this route. Moreover, As, Cr, and Ni pose cancer risks for adults and children via ingestion in the southeastern region. Overall non-carcinogenic risks emphasized a significantly higher risk for children compared to adults, with six, two-, and six-times higher health risks through ingestion of water, fish, and soils along the southeastern coast. The study offers innovative sustainable management strategies and remediation policies aimed at reducing metal(loid)s contamination in various environmental media along coastal Bangladesh.