Concentrations Of Pb Research Articles

ASSESSMENT OF CONTAMINATION AND POLLUTION RISKS CAUSED BY HEAVY METALS IN FISH POND SEDIMENTS

Pollution by heavy metals poses a significant risk to human health and ecology through the food web. Metal contamination in fish pond sediments can be caused by improper waste management and the overuse of artificial feed to increase output and profit. By using an atomic absorption spectrometer to analyse heavy metals such as Cd, Mn, Pb, and Cr, this study aims to assess the contamination levels and pollution risk from bottom sediment samples taken from 12 different fish ponds in the Rajshahi City of Bangladesh. According to this investigation, the concentrations of the metals Pb, Mn, Cr, and Cd were 0.1188 to 1.5139, 0.1899 to 0.8483, 0.0292 to 0.0395, and 0.3017 to 1.6182 mg/kg, respectively. All results show that the metal contents of all the sediments studied around the area do not exceed the standard limit. The risk assessment of the sediments was evaluated based on the geoaccumulation index, enrichment factor, and contamination factor. The analysisindicated that Cd, Pb, and Cr accumulation are within the acceptable limit except for Mn. This study provides essential baseline data on heavy metal contamination, serving as a foundation for future research by focusing on identifying contamination sources, accumulation pathways, and element mobility from feed to fish and sediment to significantly reduce environmental risks and protect both ecosystem integrity and public health.

Distribution characteristics and integrated ecological risks evaluation modelling of microplastics and heavy metals in geological high background soil

The microplastics (MPs), a novel pollutant, and heavy metals (HMs) significantly affect soil ecology. The study investigated HMs and MPs in Qianxi's high geological background soil, established a model for risk evaluation with MPs types and shapes, and proposed a two-dimensional comprehensive index model for MPs-HMs combined pollution and risk evaluation criterion. The results revealed a high soil Cd concentration, with a mean value of 0.38 mg·kg−1. Additionally, soils from soybean–wheat intercropping–potato–corn rotation (SWI-PCR) exhibited significantly higher concentrations of Hg, As, and Pb compared with those from soybean–wheat intercropping-corn rotation (SWI-CR). Moreover, the soil exhibited a high abundance of MPs (8667.66 ± 3864.26 items·kg−1), mainly characterized by PS and fiber. The mean of adjusted ecological risk index (ARI) for MPs in soil was 525.27, indicating a grade 3 risk. The two-dimensional combined index (TPI) was used to assess the ecological risk of MPs–HMs combined pollution, exhibiting an exceedance rate of 56 % with a mean of 445.07. The risk level of the combined pollution was graded as 6, indicating high risk. The microplastic risk evaluation model and the comprehensive evaluation method of combined pollution established in this study provide a reference for the future risk evaluation of multi-pollutant combined pollution.

Assessment of seasonal fluctuation in heavy metal contamination in sediments and surface water of Narmada River, India

ABSTRACT This study aimed to assess the seasonal fluctuation of heavy metal contamination in the sediments and surface water of the Narmada River. In this context, samples were gathered from six stations along the river in 2021–2022 and their concentrations were determined by utilizing Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The results in sediments, the average concentrations of As, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were 0.05, 1.03, 2.47, 1.64, 750.17, 17.75, 0.54, 0.13, and 1.12 mg/kg and in water, the average concentrations of Co, Fe, Ni, and Zn were 0.03 μg/l, 0.01 mg/l, 0.08 μg/l, and 0.39 μg/l. Seasonal fluctuation in sediments revealed that concentration of metals As, Cu, Fe, Ni, and Zn peaked during the rainy climate, while Co and Cr peaked during the post-monsoon and Mn and Pb peaked during the summer climate. Seasonal fluctuation in water, Co, Ni, and Zn exhibits their highest concentrations during the post-monsoon. The finding of pollution indices revealed that the contamination level was low to moderate. Cluster analysis revealed anthropogenic and agricultural runoff water as a contributor to contamination. The findings of this research enhance comprehension of heavy metal contamination in sediment and water of the Narmada River.

Chronic Lead Exposure in Adult Mice: Associations with miR-671/CDR1as Regulation, NF-κB Signaling, and Alzheimer's Disease-like Pathology.

Long-term exposure to lead (Pb) can result in chronic damage to the body through accumulation in the central nervous system (CNS) leading to neurodegenerative diseases, such as Alzheimer's disease (AD). This study delves into the intricate role of miR-671/CDR1as regulation in the etiology of AD-like lesions triggered by chronic Pb exposure in adult mice. To emulate the chronic effects of Pb, we established a rodent model spanning 10 months of controlled Pb administration, dividing 52 C57BL/6J mice into groups receiving varying concentrations of Pb (1, 2, or 4 g/L) alongside an unexposed control. Blood Pb levels were monitored using serum samples to ensure accurate dosing and to correlate with observed toxicological outcomes. Utilizing the Morris water maze, a robust behavioral assay for assessing cognitive functions, we documented a dose-dependent decline in learning and memory capabilities among the Pb-exposed mice. Histopathological examination of the hippocampal tissue revealed tell-tale signs of AD-like neurodegeneration, characterized by the accumulation of amyloid plaques and neurofibrillary tangles. At the molecular level, a significant upregulation of AD-associated genes, namely amyloid precursor protein (APP), β-secretase 1 (BACE1), and tau, was observed in the hippocampal tissue of Pb-exposed mice. This was accompanied by a corresponding surge in the protein levels of APP, BACE1, amyloid-β (Aβ), and phosphorylated tau (p-tau), further implicating Pb in the dysregulation of these key AD markers. The expression of CDR1as, a long non-coding RNA implicated in AD pathogenesis, was found to be suppressed in Pb-exposed mice. This observation suggests a potential mechanistic link between Pb-induced neurotoxicity and the dysregulation of the CDR1as/miR-671 axis, which warrants further investigation. Moreover, our study identified a dose-dependent alteration in the intracellular and extracellular levels of the transcription factor nuclear factor-kappa B (NF-κB). This finding implicates Pb in the modulation of NF-κB signaling, a pathway that plays a pivotal role in neuroinflammation and neurodegeneration. In conclusion, our findings underscored the deleterious effects of Pb exposure on the CNS, leading to the development of AD-like pathology. The observed modulation of NF-κB signaling and miR-671/CDR1as regulation provides a plausible mechanistic framework for understanding the neurotoxic effects of Pb and its potential contribution to AD pathogenesis.

Altering the physical properties of NiO thin films grown through the ultrasonic spray pyrolysis method by incorporating impurity lead dopants

The technology of p-type transparent semiconductors is utilized in various fields, and enhancing their performance holds industrial significance. Thus, improving the versatility and efficiency of the p-type transparent conducting oxides (TCO) has become critical for the semiconductor industries and technologies. To be used as hole carrier layes in optoelectronic devices, this study aimed to modify the physical features of nickel oxide (NiO) through a doping approach which may broaden and strengthen the usage of NiO. A cost-effective ultrasonic pyrolysis spray technique was employed for pure and lead (Pb) doped nickel oxide thin film production. The influence of the lead concentration on optical, structural, and morphological traits of the NiO nanostructures was examined via various analyses, including energy-dispersive X-ray spectroscopy (EDAX), scanning electron microscopy (SEM), Photoluminescence, UV–visible spectroscopy, X-Ray Diffraction, and Raman spectroscopy, were utilized to investigate the optical and structural characteristics of these films. In correlation, the X-Ray Diffraction results indicated that the Pb doping induced strain and altered lattice parameters of the grown nanostructures while the cubic phase of NiO maintained. The crystallite size of NiO samples ranged from 31.49 nm to 18.75 nm based on Pb doping concentration which was notably influenced by species and doping content. The UV–vis measurements demonstrated that optical parameters, such as optical band gap, were sensitive to Pb doping ratios. The Raman spectrum analysis confirmed the successful incorporation of Pb ions into NiO. Additionally, the intensity of the PL spectra decreased with increasing Pb content, offering potential applications as window layers in solar cells, smart windows, and other optoelectronic devices.

Chemical Analysis and Agricultural Utilizations of Dams Reservoir Sediments

Sediment samples were collected from King Talal Dam (KTD) and subjected to chemical, physical, and mineralogical study to test their suitability as soil replacement. The concentration of Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Nickel (Ni), Arsenic (As), Cobalt (Co), and Zinc (Zn) was obtained by atomic absorption spectrophotometer, and the elements phosphorus (P) and boron (B) were determined by using the spectrophotometric technique. These elements concentration was compared with the average concentration of soil in near by area of Jordan valley, It was found that the concentration of Cu and Zn, P, Fe, Mn, and K is within the standard range for soil fertility, and the concentration of Pb, Ni, As, Co, and Cd is within the standard range of agricultural human health safety regulation’s, the highest concentration on of iron (Fe) and manganese (Mn) in sediment were found to be 1.48% and 15.0 ppm respectively. The lowest average concentration in KTD sediment was identified for cadmium (Cd) and arsenic (As) and was found to be <0.01 and <0.05 ppm respectively. The Laboratory tests carried out indicate that the water of King Talal Dam is free of heavy metals pollutants, and reservoir sediments can be used for soil replacement and amendment. It is highly recommended to keep the percentage of sediments of KTD to soil used in agriculture within the range of 25%-50%.

Biomass yield and metal phytoextraction efficiency of Salix and Populus clones harvested at different rotation lengths in the field experiment

BackgroundPhytoextraction belongs to environmentally well-accepted remediation technologies to remove metals from contaminated soils. Due to long-time requirement, sufficient data for proper phytoextraction evaluation are missing. Four clones of fast-growing trees: two willow species (S1), Salix viminalis L. (Salix schwerinii E.L.Wolf × S. viminalis) × S. viminalis) and (S2)—Salix smithiana (Salix × smithiana Willd.), and two poplar clones (P1), Populus Max-4 (Populus nigra L. × Populus maximowiczii A. Henry) and (P2) Wolterson (P. nigra L.) were cultivated under field conditions at medium-to-high Cd and Pb, and low Zn soil contamination to assess trees’ long-term ability of biomass production and removal of potentially toxic elements (PTEs). The biomass yield and PTE uptake were measured during 8 years of regular growth under three rotation lengths: four harvests following 2-year periods (4 × 2y), two harvests in 4-year periods (2 × 4y), and one harvest representing 8 years of growth (1 × 8y).ResultsIn most cases, the highest annual dry biomass yield was achieved with a 2 × 4y rotation (P1 = 20.9 t ha−1 y−1, S2 = 18.4 t ha−1y−1), and the yield decreased in order 2 × 4y > 1 × 8y > 4 × 2y of harvesting periods. Only clone S1 showed a different pattern. The differences in biomass yield substantially affected the PTE phytoextraction. The greatest amount of Cd and Zn was removed by willow S2, with the highest biomass yield, and the strongest ability to accumulate PTEs. With 2 × 4y rotation, S2 removed a substantial amount of Cd (9.07%) and Zn (3.43%) from the topsoil horizon (0–20 cm) and 5.62% Cd and 2.04% Zn from horizon 20–40 cm; phytoextraction rate was slightly lower for 1 × 8y rotation. The poplar P1 removed the most Pb in the 1 × 8y rotation, but the overall Pb phytoextraction was negligible. The results indicated that lignin and cellulose contents increased, and hemicellulose content decreased with increased concentrations of Cd, Pb and Zn in poplars wood.ConclusionsThe data confirmed that phytoextraction over longer harvest periods offered promising results for removing Cd from medium- to high-level contaminated soils; however, the ability of Pb removal was extremely low. The longer harvest period should be more economically feasible.Graphical

Characteristics and risk assessment of potentially toxic elements pollution in river water and sediment in typical gold mining areas of Northwest China

To assess the concentration characteristics and ecological risks of potential toxic elements (PTEs) in water and sediment, 17 water samples and 17 sediment samples were collected in the Xiyu River to analyze the content of Cr, Ni, As, Cu, Zn, Pb, Cd and Hg, and the environmental risks of PTEs was evaluated by single-factor pollution index, Nemerow comprehensive pollution index, potential ecological risk, and human health risk assessment. The results indicated that Hg in water and Pb, Cu, Cd in sediments exceeded the corresponding environmental quality standards. In the gold mining factories distribution river section (X8-X10), there was a significant increase in PTEs in water and sediments, indicating that the arbitrary discharge of tailings during gold mining flotation is the main cause of PTEs pollution. The increase in PTEs concentration at the end of the Xiyu River may be related to the increased sedimentation rate, caused by the slowing of the riverbed, and the active chemical reactions at the estuary. The single-factor pollution index and Nemerow pollution index indicated that the river water was severely polluted by Hg. Potential ecological risk index indicated that the risk of Hg in sediments was extremely high, the risk of Cd was high, and the risk of Pb and Cu was moderate. The human health risk assessment indicated that As in water at point X10 and Hg in water at point X9 may pose non-carcinogenic risk to children through ingestion, and As at X8–X10 and Cd at X14 may pose carcinogenic risk to adults through ingestion. The average HQingestion value of Pb in sediments was 1.96, indicating that the ingestion of the sediments may poses a non-carcinogenic risk to children, As in the sediments at X8–X10 and X15–X17 may pose non-carcinogenic risk to children through ingestion.

Pb(II) and chlortetracycline immobilization and economy of biologically amended coastal soil

To study the pollutants immobilization and economy of biologically amended coastal soil, Alternanthera philoxeroides biomass (Bm), biochar (Bc), and dodecyldimethyl betaine (BS) modified Bc (BS-Bc) were used to amend coastal soil from Jialing, Fu, and Qu River. A runoff experiment was used to simulate the longitudinal migration and morphological changes of Pb(II) and chlortetracycline (CTC) in each amended coastal soil, and the economy of pollutants immobilization by different amended coastal soil were compared. The equilibrium time of Pb(II) and CTC in each amended coastal soil ranked in the order of BS-Bc-amended > Bc-amended > Bm-amended > unamended coastal soil. The average Pb(II) and CTC flow rate in different amended coastal soils presented an opposite trend with the equilibrium time. Pb(II) and CTC content all reduced with the increasing runoff length. Under the same soils, the content changes presented Bm and Bc amended > unamended > BS-Bc amended. CEC and clay content of coastal soils were the key factors affecting Pb(II) and CTC immobilization. The immobilization mechanisms were electrostatic attraction, ion exchange, surface precipitation, and complexation to Pb(II) and ion exchange and complexation to CTC. The economy of Pb(II) and CTC immobilization ranged from 0.5 to 9.0 and from 1.0 to 5.4 mg/¥, and coastal soil amended by BS-Bc had practical application value and high economy.

Accumulation and translocation of lead in vegetables through intensive use of organic manure and mineral fertilizers with wastewater

In many countries with wastewater irrigation and intensive use of fertilizers (minerals and organics), heavy metal deposition by crops is regarded as a major environmental concern. A study was conducted to determine the impact of mineral fertilizers, cow manure, poultry manure, leaf litter, and sugarcane bagasse on soil’s trace Pb content and edible parts of vegetables. It also evaluated the risk of lead (Pb) contamination in water, soil, and food crops. Six vegetables (Daucus carota, Brassica oleracea, Pisum sativum, Solanum tuberosum, Raphanus sativus, and Spinacia oleracea) were grown in the field under twelve treatments with different nutrient and water inputs. The lead concentrations in soil, vegetables for all treatments and water samples ranged from 1.038–10.478, 0.09346–9.0639 mg/kg and 0.036–0.26448 mg/L, The concentration of lead in soil treated with wastewater in treatment (T6) and vegetable samples was significantly higher, exceeding the WHO’s permitted limit. Mineral and organic fertilizers combined with wastewater treatment reduced lead (Pb) concentrations in vegetables compared to wastewater application without organic fertilizers. Health risk indexes for all treatments except wastewater treatment (T6) were less than one. Pb concentrations in mineral fertilizers, cow manure, poultry manure, leaf litter, and sugarcane bagasse treated were determined to pose no possible risk to consumers.

Accumulation of Heavy Metals and Their Genotoxic Potential in Medicinal Plant Verbacsum speciosum Schrad.

Background: Nowadays, the contamination of soil, water, and plants by heavy metals (HMs) presents a notable environmental problem. Methods: Lead (Pb) and zinc (Zn) levels in soil and Verbacsum speciosum populations were measured using atomic absorption spectroscopy, and meiosis in pollen mother cells (PMCs) was examined through the squash technique to evaluate genotoxic effects. Results: The results showed that Pb and Zn concentrations in the soil and, roots, and aboveground portions of all Verbacsum speciosum populations within the mining area exceeded permissible thresholds significantly. Particularly, the contaminated soil displayed average Pb and Zn concentrations of 3527.4±0.7 and 1671.4±0.5 mg/kg, respectively. The roots of Verbacsum speciosum plants closest to the mine exhibited the highest levels of Pb and Zn, measuring 204±0.05 mg/kg and 570±0.16 mg/kg, respectively. Additionally, the above-ground parts of the plants showed Pb and Zn concentrations of 312±0.12 mg/kg and 519±0.17 mg/kg, respectively. Moreover, the transfer factor (TF) for both Pb and Zn was found to be above one, indicating substantial accumulation of these metals in the above-ground portions. The presence of Pb and Zn also resulted in abnormalities during meiosis. As the distance from the mine increased, a decrease in the occurrence of meiosis abnormalities and an increase in the meiotic index (MI) were observed. Conclusion: These results highlight the potential risks to human health posed by industrial wastewater and the natural presence of HMs in soil. The ability of these metals to accumulate in plants and interfere with their meiosis underscores the importance of addressing and mitigating these hazards.

Phytoremediation Potential of Flax Grown on Multimetal Contaminated Soils: A Field Experiment.

The aim of this study was to assess the phytoremediation potential of fiber flax (Linum usitatissimatum L., var. Calista) cultivated in a soil contaminated with multiple metals, under real field conditions. A two-year (2022 and 2023) field experiment was conducted in a site contaminated with elevated concentrations of Cd, Ni, Cu, Pb, and Zn due to mining and metallurgical activities. Three different nitrogen fertilization levels were tested (N0: 0 kg N ha-1, N1: 30 kg N ha-1, N2: 60 kg N ha-1), and both spring and winter sowings were conducted. At full maturity, growth parameters and yields were measured. The phytoremediation potential of flax was assessed in terms of the metal concentrations in the above-ground biomass and of the metal uptake (i.e., the potential removal of the soil metals in g ha-1 and per year). Flax demonstrated a shorter growth cycle, with shorter and thicker plants and higher yields when sown in spring compared to winter sowing. Plant growth and productivity were not evidently influenced by additional nitrogen fertilization during plant growth. The cadmium bioaccumulation factor was 1.06, indicating that flax accumulates this metal. For Ni, Cu, Pb, and Zn, the corresponding values were 0.0, 0.04, 0.004, and 0.02, suggesting that this crop excludes these metals. The order of the higher uptake in plant tissues was as follows: Zn > Pb > Cd > Cu > Ni. In conclusion, flax demonstrated tolerance to heavy metals in the soil, effectively supporting soil restoration through cultivation. Additionally, flax showed potential as a cadmium accumulator while excluding nickel, copper, lead, and zinc.

Recycled cathode ray tube waste glasses for radiation shielding applications: Role of Na2CO3

The aim of the study is to evaluate the ability of cathode-ray tube funnel waste glasses (CRT-F) to shield photons (gamma and X-ray) and other forms of radiation with rest masses (i.e., neutrons and charged particles) after their Pb content was reclaimed. The lead (Pb) content of cathode-ray tube funnel waste glasses (CRT-F) was reduced using Na2CO3 as the reducing agent CRT-F(Na2CO3). CRT-F and CRT-F(Na2CO3) were produced using the melt and quench processes using the powder of pristine funnel glass from discarded cathode ray tube glass and the reduced glass powder, respectively, as the starting materials. The X-ray fluorescence technique was adopted for determining the chemical composition of CRT-F and CRT-F(Na2CO3) glasses. The parameters relating to the gamma photon, fissile neutron, moderated neutron, slow neutron, and charged radiation (β, H+, He2+, and C6+) attenuation abilities of pristine CRT-F and CRT-F(Na2CO3) were evaluated. The FLUKA simulation code and XCOM were used to estimate the mass attenuation coefficient of the glasses. The stopping power (Sp) and range (R) of β, H+, and He2+ were evaluated by using the NIST data-based calculators (ESTAR for β, PSTAR for H+, and ASTAR for He2+) while Sp and R data for C6+ was determined using SRIM. The cross section for fast, thermal (25 meV), and slow neutrons (0.1–10 meV) was also estimated. The Pb reclamation from the CRT-F drastically increased the half value layer of photons by at least a factor of 4 at 0.1 MeV and by more than 90 % at 10 MeV. The CRT-F interacts more with fissile and thermal neutrons compared to CRT-F(Na2CO3). Although, CRT-F showed a better ability to attenuate all the radiation types considered, both glasses are better absorbers of radiation (especially photons) than some common shields. The reduction of Pb weight in CRT-F resulted in a drastic reduction in the ability of the glass to attenuate radiation; the resulting glass (CRT-F(Na2CO3)) is however, an environmentally safer glass shield.

Effectiveness of Activated Carbon from Nutmeg Shell (Myristica fragrans) Waste as Adsorbent for Metal Ions Pb(II) and Cu(II) in Liquid Waste

Various wastes can be utilized to produce activated carbon, one of the wastes that can be utilized is nutmeg shell (Myristica fragrans). Activated carbon from nutmeg shells (Myristica fragrans) was used in this study to reduce the content of Pb(II) and Cu(II) ions in liquid waste. This research utilized the adsorption method with the batch system to determine the optimum contact time, optimum pH, and adsorption capacity. The characterization of activated carbon was done by Scanning Electron Microscopy (SEM) and Surface Area Analyzers (SAA). The content of Pb(II) and Cu(II) ions in the filtrate after adsorption was analyzed using an atomic absorption spectrophotometer (AAS). The results of SEM analysis showed that the carbon surface was cleaner and had more open pores after the activation process than before activation. The carbon surface area is 19.6243 m2.g-1. From the results of AAS analysis, the optimum time and pH for Pb(II) and Cu(II) ions was 40 min at pH 5 and 70 min at pH 4. With the Freundlich isotherm method, the adsorption capacity of the adsorbent for Pb(II) ions was 9.6028 mg.g-1 and Cu(II) ions was 0.035 mg.g-1, and the adsorption effectiveness on liquid waste for Pb and Cu metals was 1.9454 mg.g-1 and 0.4251 mg.g-1, respectively. The results showed that activated carbon from the nutmeg shell (Myristica fragrans) was able to reduce the levels of Pb(II) and Cu(II) ions in liquid waste.

Impact of heavy metals exposure on herpes simplex virus type I infection: A population‐based cross‐sectional study

AbstractThis study aims to investigate the significant relationship between serum heavy metals (lead [Pb], cadmium [Cd], mercury [Hg]) and the risk of herpes simplex virus type 1 (HSV‐1) infection. Data were derived from the National Health and Nutrition Examination Survey (NHANES) conducted in the United States from 2007 to 2016. This nationally representative survey, conducted by the National Center for Health Statistics, assessed the health status of participants through interviews, physical examinations, and laboratory tests. After excluding participants lacking serum Pb, Cd, and Hg data, as well as those missing HSV‐1 testing data and pregnant women, the analysis included 13 772 participants, among whom 3363 were adolescents. A survey‐weighted multivariate logistic regression model was used to evaluate the association between heavy metal exposure and the risk of HSV‐1 infection, and to explore the dose–response relationship between them. In adults and adolescents, serum concentrations of Pb and Cd were higher in those infected with HSV‐1 than in those not infected. However, an increase in serum Hg concentration was observed only in infected adolescents. After adjusting for potential confounders, elevated serum Pb and Cd concentrations in adults were associated with an increased risk of HSV‐1 infection. Higher serum Pb and Cd concentrations were associated with an increased risk of HSV‐2 infection, irrespective of HSV‐1 infection status. In adults, serum concentrations of Pb and Hg showed an approximately linear relationship with HSV‐1 infection risk (p for nonlinearity > 0.05), whereas the dose–response relationship between serum Cd concentration and HSV‐1 infection was nonlinear (p for nonlinearity = 0.004). In adolescents, serum concentrations of heavy metals (Pb, Cd, Hg) showed an approximately linear relationship with HSV‐1 infection (p for nonlinearity > 0.05). Furthermore, the study examined the relationship between serum heavy metal levels and the risk of HSV‐1 infection across different genders, races, income levels, weight statuses, and immune statuses. In conclusion, there is a significant association between serum heavy metal concentrations and HSV‐1 infection, which warrants further investigation into the causal relationship between them.

Growth, gas exchange, and leaf anatomy of Echinodorus grandiflorus (Cham. & Schltr.) Micheli under Pb contamination.

Lead (Pb) can be deposited in aquatic environments that are especially subject to pollution due to wastewater and sewage disposal. This study aimed to evaluate the tolerance of Echinodorus grandiflorus (Cham. & Schltr.) Micheli to Pb and changes in growth, gas exchange, and leaf anatomy. Experiments were conducted with E. grandiflorus plants exposed to the following Pb concentrations in nutrient solution: [0; 0.75; 1.5; 3.0 and 9.0μM Pb (NO 3)2] in a greenhouse for 60days. At the end of the experiment, the lead concentration, growth, leaf gas exchange, and changes in leaf anatomy were evaluated. There was no mortality of E. grandiflorus plants, and they accumulated higher concentrations of Pb proportional to the concentration of the pollutant in the solution. Pb did not cause significant changes in growth, stomatal conductance, transpiration, and Ci/Ca rate but reduced the photosynthesis in E. grandiflorus. The leaf anatomy showed significant changes in the presence of Pb, reducing the epidermis and chlorophyll parenchyma. E. grandiflorus demonstrated tolerance to Pb, surviving and growing under contamination; however, it negatively modified its leaf anatomy and photosynthesis in the presence of the metal.

RBOH-dependent H2O2 burst induced by silicon dioxide nanoparticles establishes systemic acquired acclimation in quinoa under lead toxicity

The role of silicon dioxide nanoparticles (nSiO2) and hydrogen peroxide (H2O2) in heavy metal tolerance of plants has been well defined; however, their interaction together remains largely unknown. Therefore, two experiments were conducted to determine whether RBOH-dependent signaling is involved in nSiO2-induced systemic lead (Pb) acclimation in Chenopodium quinoa. In the first experiment, quinoa leaves were sprayed with nSiO2 (0, 2, 4 mM) under various Pb concentrations (0, 200 and 400 µM). After 12 h, an H2O2 burst, and higher transcription levels of RBOHD and PCS1 genes (encoding NADPH oxidase and phytochelatin synthase) were recorded in leaves of nSiO2-treated plants. After 15 days, Pb toxicity reduced growth parameters, and Chl a, Chl b contents and increased electrolyte leakage, and foliar spray with nSiO2 reversed this tendency. In the second experiment, foliar application of 4 mM nSiO2 minimized intracellular H2O2 and O2˙¯ and reduced malondialdehyde content and leaf Pb concentration under 400 µM Pb. While, this treatment increased the content of reduced ascorbate, and thiol compounds and enhanced the activities of superoxide dismutase and ascorbate peroxidase not only in leaves but also in untreated roots. However, H2O2 scavenging with DMTU and the inhibition of RBOH-dependent signaling by DPI aggravated Pb phytotoxicity and impaired the beneficial effects of nSiO2 on aforementioned attributes; thereby reduced tolerance index in both leaves and roots. Together, our pharmacological and molecular evidence for the first time unraveled that RBOH-dependent H2O2 burst plays vital role in triggering nSiO2-induced systemic acquired acclimation in Pb-stressed plants.

Assessment of toxic elements in selected fish species in the marine water at Jamestown, Ghana

Fish is an excellent source of low-fat protein. Fish contains a lot of omega-3 fatty acids, as well as vitamins D and B2 (riboflavin). The daily consumption of contaminated food, especially fish, is among the primary cause of heavy metals pollution to human health. The aim of the research was to determine the concentration of heavy metals in selected species of fish from the Gulf of Guinea at James Town in Ghana. In tandem with the study's objective, samples of different forms of fish, Cassava fish, Flatfish, Redfish, Kingfish, and Silverfish, and sediment were obtained and analyzed for the presence of heavy metals using atomic absorption spectrometer (PerkinElmer®, PinAAcle 900T). The analysis indicated a high concentration of Pb, Cd, and Cr concentrations in fish gills, muscles, and sediment. High lead concentration in Silverfish gills (5.9 mg/kg) and Flatfish gills (2.29 mg/kg) above WHO levels. Cadmium was found in all fish species and sediment except Kingfish. Chromium concentrations were high n Cassava fish (3.10 mg/kg) and Silverfish (4.01 mg/kg) and copper concentrations were absent in the fish species. Arsenic and mercury were also not detected in all fish species and sediment. Manganese concentrations were found in fish and sediment. High cadmium target hazard quotient (0.17–11.60 for adults and 0.24 to 16.24 for children) and cancer risk (0.00–0.04) values in fish samples indicated potential health concerns. The Hazard Index (HI) for the analyzed samples ranged from 0.00 to 12.48 for adults and 0.00 to 17.47 for children. The study suggests that eliminating pollution and other sources of waterbody pollution is crucial to protecting the marine environment and the health of seafood consumers.

Occupational and human health risks of exposure to potentially toxic elements (PTEs) in top soils from steel fabrication workshops

IntroductionEnvironmental pollution caused by potentially toxic elements (PTEs) from anthropogenic sources has become a global concern due to its deleterious effect on humans and ecosystem health. Therefore, this study evaluated the concentrations of PTEs, pollution level and human health risk in topsoil from ten (10) steel fabrication workshops in Abeokuta, Ogun State, Nigeria. Materials and methodsTen (10) composite soil samples were collected in November 2023, from 10 different steel fabrication workshops in proximity to residence in Abeokuta, Ogun State, Nigeria. One (1) gram of processed sample was digested using aqua regia and PTE concentration estimated using atomic absorption spectrophotometer (AAS). Pollution index assessment was determined using enrichment factor (EF) and geo-accumulation index (I-geo) while descriptive statistics and correlation were subjected to statistical package for social sciences (SPSS). ResultsThe result showed that Iron (Fe) (11,500 – 42,100 mg kg−1), Lead (Pb) (10.7 – 583 mg kg−1), Chromium (Cr) (16.3 - 49.7 mg kg−1), Zinc (Zn) (34.6 – 343 mg kg−1), Manganese (Mn) (109 – 840 mg kg−1), Nickel (Ni) (2.23 - 25.3 mg kg−1), Copper (Cu) (16.6 -107 mg kg−1) and Cadmium (Cd) (2.23 - 25.3 mg kg−1) were present. Mean concentration for Pb (179±202 mg kg−1) is higher than the Canada soil guideline value (CSGV) (140 mg kg−1) while other PTEs are within the recommended limit. Pollution indices revealed EF (Cd and Pb) and I-geo (Cd) as the primary pollutants in the soil while the strong significant correlation between Cr, Cu and Mn p < 0.05. Cr, Ni, Pb and that of Cu, Mn, Ni, Pb, Zn p < 0.01 suggest an emanation from both geogenic and anthropogenic sources. Human health risk assessment revealed Fe as the most dosed PTE and ingestion as the major pathways of exposure especially to children being the most susceptible. Hazard index (HI) and total cancer risk (TCR) values for PTEs were <1 and within the acceptable threshold (1 × 10−6 – 1 × 10−4) except for Pb (3.93E+01; 1.16E-03) in adults respectively. ConclusionThe study showed that the topsoil from the steel fabrication workshop is polluted with Pb and Cu toxicity and the adult (residents and workers) population exposed to the soil is potentially at a non-cancer and cancer risk.

Lead exposure estimation through a physiologically based toxicokinetic model using human biomonitoring data and comparison with scenario-based exposure assessment: A case study in Korean adults

Pb toxicity is linked to cardiovascular and nephrotoxicity issues. Exposure to this heavy metal can occur through food and drinking water. Therefore, this study aimed to evaluate Pb exposure and assess health risks in Korean adults using a physiologically based toxicokinetic (PBTK) model. Human blood Pb concentrations were monitored using the Korean National Environmental Health Survey (KoNEHS) Cycle 4. The average Pb exposure in Korean adults was 0.520 μg/kg bw/day. The PBTK results were compared with scenario-based results from the 2021 risk assessment report of five heavy metals, including Pb, conducted by the MFDS. Exposure determined through reverse dosimetry was approximately two times higher than scenario-based exposure (0.264 μg/kg bw/day). The higher exposure levels obtained during PBTK analysis may be attributed to sustained exposure within historically more contaminated living environments and the long half-life of Pb. These findings suggest that the PBTK-based method can quantify aggregated exposure levels in the body over time, potentially serving as a complementary tool to address the constraints of scenario-based assessment methods for integrated risk assessment. Moreover, this model is convenient and cost-effective compared with scenario-based exposure estimation. These findings can facilitate the application of model for tracking continuous national changes in hazardous substance levels.