The use of a portable X-ray fluorescence spectrometer for measuring nickel in plants: sample preparation and validation.

X-ray fluorescence is a fast, cost-effective, and eco-friendly method for elemental analyses. Portable X-ray fluorescence spectrometers (pXRF) have proven instrumental in detecting metals across diverse matrices, including plants. However, sample preparation and measurement procedures need to be standardized for each instrument. This study examined sample preparation methods and predictive capabilities for nickel (Ni) concentrations in various plants using pXRF, employing empirical calibration based on inductively coupled plasma optical emission spectroscopy (ICP-OES) Ni data. The evaluation involved 300 plant samples of 14 species with variable of Ni accumulation. Various dwell times (30, 60, 90, 120, 300 s) and sample masses (0.5, 1.0, 1.5, 2.0 g) were tested. Calibration models were developed through empirical and correction factor approaches. The results showed that the use of 1.0 g of sample (0.14 g cm-2) and a dwell time of 60 s for the study conditions were appropriate for detection by pXRF. Ni concentrations determined by ICP-OES were highly correlated (R2 = 0.94) with those measured by the pXRF instrument. Therefore, pXRF can provide reliable detection of Ni in plant samples, avoiding the digestion of samples and reducing the decision-making time in environmental management.

Spatial health risk assessments of nickel in the groundwater sources of a mining-impacted area.

Mining activities have increased the potential risks of metal pollution to the groundwater resources in arid areas across the globe. Therefore, this study aimed to examine the health risk associated with nickel (Ni) in the groundwater sources of a mining-impacted area, South Khorasan, Eastern Iran. A total of 110 stations were included in the study, comprising 62 wells, 40 qanats, and 8 springs in summer, 2020. Initially, the collected samples were tested for temperature, pH, and electrical conductivity (EC). Subsequently, the samples were filtered and treated with nitric acid (HNO3) to measure the concentration of Ni using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Hazard quotient (HQ) and non-carcinogenic risk assessments were employed to evaluate the potential risks of Ni to the inhabitants. The findings revealed that the concentration of Ni ranged from 0.02 to 132.39 µg l-1, and only two stations exhibited Ni concentrations above the WHO standards (20 µg l-1). The results demonstrated that 98.21% of the sampled locations had HQ values below one, indicating negligible risk, while 1.78% of the stations exhibited HQ values of one or higher, representing a high non-carcinogenic risk for water consumers. Overall, the concentration of nickel in the groundwater of South Khorasan exceeded the World Health Organization (WHO) limit solely in the Halvan station, posing a non-carcinogenic risk for the residents in that area, and therefore, additional efforts should be made to provide healthier groundwater to consumers in this region.

High-efficiency combination washing agents with eco-friendliness simultaneously removing Cd, Cu and Ni from soil of e-waste recycling site: A lab-scale experiment.

Soil washing technology plays an important role in the removal of heavy metals, and the efficacy of this process depends on the washing agent used. Due to the difficulty in treating soils contaminated by multiple heavy metals, there is still a need for further exploration of efficient washing agents with low environmental impact. Although single washing agents, such as chelators, can also effectively remove heavy metals from soil, combining efficient washing agents and determining their optimal washing conditions can effectively improve their removal efficiency for multiple heavy metals in soil simultaneously. Based on the previous research, the present study was carried out to combine different types of washing agents to remediate contaminated soils at a commonly e-waste recycling site. The objectives were to investigate their efficient washing conditions and assess the impact of the washing process on the speciation distribution and pollution level associated with heavy metals in soil. The results showed that the combination of HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) and FeCl3 at a ratio of 6:4 exhibited the most effective removal of Cd, Cu and Ni from the contaminated soil at an e-waste recycling site. Under optimal washing conditions, with a soil-to-liquid ratio of 1:20 and a washing time of 48 h, the removal rates of Cd, Cu and Ni were 96.72%, 69.91% and 76.08%, respectively. It needed to be emphasized that the combination washing agents were able to remove most of the acid-soluble, reducible and oxidizable fractions of heavy metals, and even the removal rates of the stable residual fraction (e.g., of Cd) was at a relatively high level. In addition, the washing process significantly reduced the pollution level associated with heavy metals in soil. This study aid in the development of combined efficient washing agents and explores optimal washing strategies for the remediation of Cd, Cu, and Ni-contaminated soil at e-waste recycling sites. The findings may play a role in enhancing the remediation capabilities for soils contaminated with multiple heavy metals, due to its characteristics of and high-efficiency and environmental friendliness.

Human health risks of heavy metal(loid)s mediated through crop ingestion in a coal mining area in Eastern China.

The heavy metal(loid)s (HMs) in soils can be accumulated by crops grown, which is accompanied by crop ingestion into the human body and then causes harm to human health. Hence, the health risks posed by HMs in three crops for different populations were assessed using Health risk assessment (HRA) model coupled with Monte Carlo simulation. Results revealed that Zn had the highest concentration among three crops; while Ni was the main polluting element in maize and soybean, and As in rice. Non-carcinogenic risk for all populations through rice ingestion was at an "unacceptable" level, and teenagers suffered higher risk than adults and children. All populations through ingestion of three crops might suffer Carcinogenic risk, with the similar order of Total carcinogenic risk (TCR): TCRAdults > TCRTeenagers > TCRChildren. As and Ni were identified as priority control HMs in this study area due to their high contribution rates to health risks. According to the HRA results, the human health risk was associated with crop varieties, HM species, and age groups. Our findings suggest that only limiting the Maximum allowable intake rate is not sufficient to prevent health risks caused by crop HMs, thus more risk precautions are needed.

Ecological impacts and potential hazards of nickel on soil microbes, plants, and human health.

Nickel (Ni) contamination poses a serious environmental concern, particularly in developing countries: where, anthropogenic activities significantly contributes to Ni accumulations in soils and waters. The contamination of agricultural soils with Ni, increases risks of its entry to terrestrial ecosystems and food production systems posing a threat to both food security and safety. We examined the existing published articles regarding the origin, source, accumulation, and transport of Ni in soil environments. Particularly, we reviewed the bioavailability and toxic effects of Ni to soil invertebrates and microbes, as well as its impact on soil-plant interactions including seed germination, nutrient uptake, photosynthesis, oxidative stress, antioxidant enzyme activity, and biomass production. Moreover, it underscores the potential health hazards associated with consuming crops cultivated in Ni-contaminated soils and elucidates the pathways through which Ni enters the food chain. The published literature suggests that chronic Ni exposure may have long-term implications for the food supply chain and the health of the public. Therefore, an aggressive effort is required for interdisciplinary collaboration for assessing and mitigating the ecological and health risks associated with Ni contamination. It also argues that these measures are necessary in light of the increasing level of Ni pollution in soil ecosystems and the potential impacts on public health and the environment.

Assessing the health risks of heavy metals and seasonal minerals fluctuations in Camellia sinensis cultivars during their growth seasons.

The risk assessment of heavy metals in tea is extremely imperative for the health of tea consumers. However, the effects of varietal variations and seasonal fluctuations on heavy metals and minerals in tea plants remain unclear. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to evaluate the contents of aluminum (Al), manganese (Mn), magnesium (Mg), boron (B), calcium (Ca), copper (Cu), cobalt (Co), iron (Fe), sodium (Na), zinc (Zn), arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and antimony (Sb) in the two categories of young leaves (YL) and mature leaves (ML) of tea (Camellia sinensis) cultivars throughout the growing seasons. The results showed significant variations in the contents of the investigated nutrients both among the different cultivars and growing seasons as well. Furthermore, the average concentrations of Al, Mn, Mg, B, Ca, Cu, Co, Fe, Na, Zn, As, Cd, Cr, Ni, and Sb in YL ranged, from 671.58-2209.12, 1260.58-1902.21, 2290.56-2995.36, 91.18-164.68, 821.95-5708.20, 2.55-3.80, 3.96-25.22, 37.95-202.84, 81.79-205.05, 27.10-69.67, 0.028-0.053, 0.065-0.127, 2.40-3.73, 10.57-12.64, 0.11-0.14 mg kg-1, respectively. In ML, the concentrations were 2626.41-7834.60, 3980.82-6473.64, 3335.38-4537.48, 327.33-501.70, 9619.89-13153.68, 4.23-8.18, 17.23-34.20, 329.39-567.19, 145.36-248.69, 40.50-81.42, 0.089-0.169, 0.23-0.27, 5.24-7.89, 18.51-23.97, 0.15-0.19 mg kg-1, respectively. The contents of all analyzed nutrients were found to be higher in ML than in YL. Target hazard quotients (THQ) of As, Cd, Cr, Ni, and Sb, as well as the hazard index (HI), were all less than one, suggesting no risk to human health via tea consumption. This research might provide the groundwork for essential minerals recommendations, as well as a better understanding and management of heavy metal risks in tea.

Identification of the single and combined acute toxicity of Cr and Ni with Heterocypris sp. and the quantitative structure-activity relationship (QSAR) model.

Mining wastewater with heavy metals poses a serious threat to the ecological environment. However, the acute single and combined ecological effects of heavy metals, such as chromium (Cr) and nickel (Ni), on freshwater ostracods, and the development of relevant prediction models, remain poorly understood. In this study, Heterocypris sp. was chosen to investigate the single and combined acute toxicity of Cr and Ni. Then, the quantitative structure-activity relationship (QSAR) model was used to predict the combined toxicity of Cr and Ni. The single acute toxicity experiments revealed high toxicity for both Cr and Ni. In addition, Cr exhibited greater toxicity compared to Ni, as evidenced by its lower 96-hour half-lethal concentration (LC50) of 1.07 mg/L compared to 4.7 mg/L for Ni. Furthermore, the combined acute toxicity experiments showed that the toxicity of Cr-Ni was higher than Ni but lower than Cr. Compared with the concentration addition (CA) and independent action (IA) models, the predicted results of the QSAR model were more consistent with the experimental results for the Cr-Ni combined acute toxicity. So, the high accuracy of QSAR model identified its feasibility to predict the toxicity of heavy metal pollutants in mining wastewater.

Trace elements in commercially available infant formulas in Iran: Determination and estimation of health risks.

Infants are significantly more vulnerable to trace elements from their foods. The objective of the present study was to ascertain the concentrations of some trace elements namely; arsenic, cadmium, chromium, copper, nickel and lead in infant formulas sold in Iran and to estimate the potential health risks to the infants through consumption of these products. The mean concentrations of As, Cd, Cr, Cu, Ni and Pb in infant formula samples were 0.006, 0.040, 0.3980, 2.014, 0.166 and 0.285 mg/kg, respectively. The mean levels of the trace elements were in the following order: Cu > Cr > Pb > Ni > Cd > As. For arsenic, cadmium and copper, calculated EWIs (estimated weekly intakes) were within the PTWIs (provisional tolerated weekly intakes) recommended by FAO/WHO. For chromium, nickel and lead, the calculated EWIs were higher than the PTWIs in 88.8 %, 75 %, and 61.1 % of the formulas. HQs of Pb, Cu, Cd and As were above the safe limits, indicating health concerns from the consumption of some infant formulas. Based on the CR classification, CR values of some elements including Cd, Cr and Ni were above 1 × 10-4 in some brands, indicating that exposure to these elements from infant formulas may cause health risks. Therefore, regular monitoring of all the raw materials, stages of production and storage of infant formulas is essential to limit the exposure of this vulnerable age group to toxic trace elements.

Serpentine environment prevails over geographic distribution in shaping the genetic diversity of Medicago lupulina L.

Edaphic conditions of serpentine soils, naturally rich in heavy metals, act as a strong selection pressure that shapes specific metal-tolerant ecotypes. Medicago lupulina L. (black medick) is not only a widespread plant species that prefers calcareous and dry soil types but also grows at the borders of serpentine formations. It can also be found in waste and disturbed habitats. This is a species with reported phytoremediation potential, however, there is no published data regarding the impact of the environment on the genetic distribution of this species. The aim of our research was to explore how selection pressure of serpentine soils affects genetic diversity of M. lupulina and to test heavy-metal accumulation capacity of this species. Specimens of 11 M. lupulina populations were collected from serpentine outcrops located in Central and Eastern Bosnia as well as from non-serpentine sites. Soil and plant samples were analyzed for the total contents of heavy metals using air-acetylene flame atomic absorption spectroscopy. Genetic diversity was analyzed using AFLP (Amplified Fragment Length Polymorphism) markers. Serpentine soils showed high nickel, cobalt, chromium and iron concentrations. Nickel and manganese concentrations in soil samples and plant material showed statistically significant correlation. Although plants in two populations show the ability to extract Ni, M. lupulina does not show hyperaccumulating properties. Despite severe selective pressure, genetic diversity in serpentine populations is not reduced. Analyses of intrapopulation and interpopulation genetic diversity showed significant genetic differentiation among populations which is not related to their geographic distance. Population from non-metalliferous soil showed clear separation from all other populations. Diversity data suggest that serpentine populations maintain genetic diversity by undetected mechanisms and that edaphic factors rather than geography influence genetic structure analyzed M. lupulina populations.

Mixture effects of trace element levels on cardiovascular diseases and type 2 diabetes risk in adults using G-computation analysis.

There is an increasing concern about the health effects of exposure to a mixture of pollutants. This study aimed to evaluate the associations between serum levels of heavy/essential metals ([Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Nickel (Ni), Chromium (Cr), Copper (Cu), Iron (Fe), and Zinc (Zn)]) and the risk of developing cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2D). Data were collected from 450 participants (150 with CVDs, 150 with T2D, and 150 healthy subjects) randomly selected from the Ravansar Non-Communicable Disease (RaNCD) cohort in Western Iran, covering the years 2018-2023. Trace element levels in the serum samples were assayed using ICP-MS. Logistic regression was performed to estimate the adjusted risk of exposure to single and multi-metals and CVD/T2D. Odds ratios were adjusted for age, sex, education, residential areas, hypertension, and BMI. The mixture effect of exposure to multi-metals and CVD/T2D was obtained using Quantile G-computation (QGC). In the logistic regression model, chromium, nickel, and zinc levels were associated with CVD, and significant trends were observed for these chemical quartiles (P < 0.001). Arsenic, chromium, and copper levels were also associated with T2D. The weight quartile sum (WQS) index was significantly associated with both CVD (OR 4.17, 95% CI 2.16-7.69) and T2D (OR 11.96, 95% CI 5.65-18.26). Cd, Pb, and Ni were the most heavily weighed chemicals in these models.The Cd had the highest weight among the metals in the CVD model (weighted at 0.78), followed by Hg weighted at 0.197. For T2D, the serum Pb (weighted at 0.32), Ni (weighted at 0.19), Cr (weighted at 0.17), and Cd (weighted at 0.14) were the most weighted in the G-computation model. The results showed the significant role of toxic and essential elements in CVDs and T2D risk. This association may be driven primarily by cadmium and mercury for CVDs and Pb, Ni, Cr, and Cd for T2D, respectively. Prospective studies with higher sample sizes are necessary to confirm or refute our preliminary results as well as to determine other important elements.

Accumulation of potentially toxic elements in fourfinger threadfin (Eleutheronema tetradactylum) and black pomfret (Parastromateus niger) from Selangor, Malaysia.

The accumulation of potentially toxic elements (PTEs) has raised public awareness due to harmful contamination to both human and marine creatures. This study was designed to determine the concentration of copper (Cu), zinc (Zn), cadmium (Cd), and nickel (Ni) in the intestine, kidney, muscle, gill, and liver tissues of local commercial edible fish, fourfinger threadfin (Eleutheronema tetradactylum), and black pomfret (Parastromateus niger) collected from Morib (M) and Kuala Selangor (KS). Among the studied PTEs, Cu and Zn were essential elements to regulate body metabolism with certain dosages required while Cd and Ni were considered as non-essential elements that posed chronic and carcinogenic risk. The concentration of PTEs in fish tissue samples was analyzed using flame atomic absorption spectrometry (F-AAS). By comparing the concentration of PTEs in fish tissues as a bioindicator, the environmental risk of Morib was more serious than Kuala Selangor because both fish species collected from Morib resulted in a higher PTEs concentration. For an average 62 kg adult with a fish ingestion rate (FIR) of 0.16 kg/person/day in Malaysia, the estimated weekly intake (EWI) of Cd from the consumption of E. tetradactylum (M: 0.0135 mg/kg; KS: 0.0134 mg/kg) and P. niger (M: 0.0140 mg/kg; KS: 0.0132 mg/kg) had exceeded the provisional tolerable weekly intake (Cd: 0.007 mg/kg) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference dose (ORD) values of Cd (0.001 mg/kg/day) as provided by the United States Environmental Protection Agency (USEPA) regional screening level, thus it posed chronic risks for daily basis consumption. Besides, the value of the carcinogenic risk of Cd (0.7-3 to 0.8-3) and Ni (0.5-3 to 0.6-3) were in between the acceptable range (10-6 to 10-4) of the health index that indicates a relatively low possibility cancer occurrence to the consumers in both Morib and Kuala Selangor. This study recommended FIR to be 0.80 kg/person/day to reduce the possibility of posing chronic and carcinogenic risks while at the same time obtaining the essential nutrients from the fish.

Degradation of sulfamethazine by microbial electrolysis cell with nickel-cobalt co-modified biocathode.

In this study, nickel-cobalt co-modified stainless steel mesh (Ni-Co@SSM) was prepared and used as the biocathode in microbial electrolysis cell (MEC) for sulfamethazine (SMT) degradation. The optimal electrochemical performance of the Ni-Co@SSM was obtained at the electrodeposition time of 600 s, electrodeposition current density of 20 mA cm-2, and nickel-cobalt molar ratio of 1:2. The removal of SMT in MEC with the Ni-Co@SSM biocathode (MEC-Ni-Co@SSM) was 82%, which increased by 30% compared with the conventional anaerobic reactor. Thirteen intermediates were identified and the potential degradation pathways of SMT were proposed. Proteobacteria, Firmicutes, Patescibacteria, Chloroflexi, Bacteroidetes, and Euryarchaeota are the dominant bacteria at the phylum level in the MEC-Ni-Co@SSM, which are responsible for SMT metabolism. Due to the electrical stimulation, there was an increase in the abundance of the metabolic function and the genetic information processing. This work provides valuable insight into utilizing MECs for effective treatment of antibiotic-containing wastewater.

Pollution indices of selected metals in tea (Camellia sinensis L.) growing soils of the Upper Assam region divulge a non-trifling menace of National Highway.

The study investigated the influence of a National Highway (NH) traversing tea estates (TEs) on heavy metal (HM) contamination in the top soils of Upper Assam, India. The dispersion and accumulation of six HMs, viz. cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn), within tea-growing soils were assessed using diverse indices: contamination factor (CF), degree of contamination (DC), enrichment factor (EF), geo-accumulation index (Igeo), modified degree of contamination (MDC), Nemerow pollution index (PINemerow), pollution load index (PLI), potential ecological risk factor (Eri), and potential ecological risk index (RI). The order of HM prevalence was Fe > Mn > Zn > Ni > Cu > Cd. Elevated Cd levels near the NH prompted immediate attention, while Cd and Zn showed moderate pollution in CF, EF, and RI. The remaining metals posed minimal individual risk (Eri< 40), resulting in an overall contamination range of "nil to shallow," signifying slight contamination from the studied metals. From MDC values for investigated metals, it was found to be "zero to very low degree of contamination" at all locations except the vicinity of NH. Soil pollution, as determined by PLI, indicated unpolluted soils in both districts, yet PINemerow values indicated slight pollution. The statistical analysis revealed that there is a significant decrease in most of the indices of HM as the distance from NH increases. The application of multivariate statistical techniques namely Principal Component Analysis and Cluster Analysis showed the presence of three distinct homogenous groups of distances based on different indices. This investigation underscores NH-associated anthropogenic effects on TE soil quality due to HM deposition, warranting proactive mitigation measures.

Nickel stocks and fluxes in a tropical agromining 'metal crop' farming system in Sabah (Malaysia).

Nickel hyperaccumulator plants play a major role in nickel recycling in ultramafic ecosystems, and under agromining the nickel dynamics in the farming system will be affected by removal of nickel-rich biomass. We investigated the biogeochemical cycling of nickel as well as key nutrients in an agromining operation that uses the metal crop Phyllanthus rufuschaneyi in the first tropical metal farm located in Borneo (Sabah, Malaysia). For two years, this study monitored nine 25-m2 plots and collected information on weather, biomass exportation, water, and litter fluxes to the soil. Without harvesting, nickel inputs and outputs had only minor contributions (<1 %) to the total nickel budget in this system. The nickel cycle was mainly driven by internal fluxes, particularly plant uptake, litterfall and throughfall. After two years of cropping, the nickel litter flux corresponded to 50 % of the total nickel stock in the aerial biomass (3.1 g m-2 year-1). Nickel was slowly released from the litter; after 15 months of degradation, 60 % of the initial biomass and the initial nickel quantities were still present in the organic layer. Calcium, phosphorus and potassium budgets in the system were negative without fertilisation. Unlike what is observed for nickel, sustained agromining would thus lead to a strong depletion of calcium stocks if mineral weathering cannot replenish it.

Integrated assessment of the pollution and risk of heavy metals in soils near chemical industry parks along the middle Yangtze River.

Industrialization in riparian areas of critical rivers has caused significant environmental and health impacts. Taking eight industrial parks along the middle Yangtze River as examples, this study proposes a multiple-criteria approach to investigate soil heavy metal pollution and associated ecological and health risks posed by industrial activities. Aiming at seven heavy metals, the results show that nickel (Ni), cadmium (Cd), and copper (Cu) exhibited the most significant accumulation above background levels. The comprehensive findings from Pearson correlation analysis, cluster analysis, principal component analysis, and industrial investigation uncover the primary sources of Cd, arsenic (As), mercury (Hg), and lead (Pb) to be chemical processing, while Ni and chromium (Cr) are predominantly derived from mechanical and electrical equipment manufacturing. In contrast, Cu exhibits a broad range of origins across various industrial processes. Soil heavy metals can cause serious ecological and carcinogenic health risks, of which Cd and Hg contribute to >70 % of the total ecological risk, and As contributes over 80 % of the total health risk. This study highlights the importance of employing multiple mathematical and statistical models in determining and evaluating environmental hazards, and may aid in planning the environmental remediation engineering and optimizing the industry standards.

Sociodemographic inequities in the burden of carcinogenic industrial air emissions in the United States.

BACKGROUND: Industrial facilities are not located uniformly across communities in the United States, but how the burden of exposure to carcinogenic air emissions may vary across population characteristics is unclear. We evaluated differences in carcinogenic industrial pollution among major sociodemographic groups in the United States and Puerto Rico. METHODS: We evaluated cross-sectional associations of population characteristics including race and ethnicity, educational attainment, and poverty at the census tract level with point-source industrial emissions of 21 known human carcinogens using regulatory data from the US Environmental Protection Agency. Odds ratios and 95% confidence intervals comparing the highest emissions (tertile or quintile) to the referent group (zero emissions [ie, nonexposed]) for all sociodemographic characteristics were estimated using multinomial, population density-adjusted logistic regression models. RESULTS: In 2018, approximately 7.4 million people lived in census tracts with nearly 12 million pounds of carcinogenic air releases. The odds of tracts having the greatest burden of benzene, 1,3-butadiene, ethylene oxide, formaldehyde, trichloroethylene, and nickel emissions compared with nonexposed were 10%-20% higher for African American populations, whereas White populations were up to 18% less likely to live in tracts with the highest emissions. Among Hispanic and Latino populations, odds were 16%-21% higher for benzene, 1,3-butadiene, and ethylene oxide. Populations experiencing poverty or with less than high school education were associated with up to 51% higher burden, irrespective of race and ethnicity. CONCLUSIONS: Carcinogenic industrial emissions disproportionately impact African American and Hispanic and Latino populations and people with limited education or experiencing poverty thus representing a source of pollution that may contribute to observed cancer disparities.

Efficacious adsorption of divalent nickel ions over sodium alginate-g-poly(acrylamide)/hydrolyzed Luffa cylindrica-CoFe2O4 bionanocomposite hydrogel.

Existing Ni2+ heavy metal ions in an aqueous medium are highly hazardous for living organisms and humans. Therefore, designing low-cost adsorbents with enhanced effectiveness is essential for removing nickel ions to safeguard public health. In this study, a novel green nanocomposite hydrogel was synthesized through the free radical solution and bulk polymerization method, and its capability to remove divalent nickel ions from aqueous media was examined. The bionanocomposite hydrogel named as SA-g-poly(AAm)/HL-CoFe2O4 was produced by grafting polyacrylamide (AAm) onto sodium alginate (SA) in the presence of a magnetic composite recognized as HL-CoFe2O4, where HL represents hydrolyzed Luffa Cylindrica. By employing FT-IR, XRD, VSM, SEM, EDX-Map, BET, DLS, HPLC, and TGA techniques, morphological evaluation and characterization of the adsorbents were carried out. The performance of the adsorption process was studied under varying operational conditions including pH, temperature, contact duration, initial concentration of pollutant ions, and adsorbent dosage. HPLC analysis proved the non-toxic structure of the bionanocomposite hydrogel. The number of unreacted acrylamide monomers within the hydrogel matrix was measured at 20.82 mg/kg. The optimum conditions was discovered to be pH = 6, room temperature, adsorbent dosage of 1 of g.L-1, initial Ni2+ concentration of 10 mg.L-1, and contact time of 100 min, and the maximum adsorption efficiency at optimal state was calculated as 70.09, 90.25, and 93.83 % for SA-g-poly (AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples, respectively. Langmuir isotherm model was in good agreement with the experimental data and the maximum adsorption capacity of SA-g-poly(AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples was calculated to be 31.37, 43.15, and 45.19 mg.g-1, respectively. The adsorption process, according to kinetic studies, follows a pseudo-second-order kinetic model. Investigations on thermodynamics also demonstrated that the process is exothermic and spontaneous. Exploring the interference effect of co-existing ions showed that the adsorption efficiency has decreased with concentration enhancement of Ca2+ and Na+ cations in aqueous medium. Furthermore, the adsorption/desorption assessments revealed that after 8 consecutive cycles, there had been no noticeable decline in the adsorption effectiveness. Finally, actual wastewater treatment outcomes demonstrated that the bionanocomposite hydrogel successfully removes heavy metal pollutants from shipbuilding industry effluent. Therefore, the findings revealed that the newly fabricated bionanocomposite hydrogel is an efficient, cost-effective, easy-separable, and green adsorbent that could be potentially utilized to remove divalent nickel ions from wastewater.

Assessment of human health risks associated with airborne arsenic, nickel and lead exposure in particulate matter from vehicular sources in Sao Paulo city.

Air pollution is a critical public health concern. The present study assessed the risk to human health of airborne Potentially Toxic Elements (PTE) arsenic, nickel and lead exposure in particulate matter (PM10-2.5) in Sao Paulo, Brazil. Statistical analysis was performed using R Software and the risk assessment for human health was carried out according to the methods of the United States Environmental Protection Agency. The results for mean annual concentration of PTE (ng m-3) were within the limits stipulated for air-quality by international agencies (arsenic <6, nickel <20 and lead <150). Airborne arsenic and lead showed higher mean concentrations during the winter than the other seasons (p < 0.05). However, the results showed a greater health risk for the adult population and during the winter season. These findings highlight the importance of air pollution as a risk factor for population health.

Potentially toxic elements (PTEs) in coastal sediments of Bandar Abbas city, North of Persian Gulf: An ecological risk assessment.

The concentration of potentially toxic elements (PTEs; Lead (Pb), Nickel (Ni), and Cadmium (Cd) Pb, Ni, and Cd), using flame atomic absorption spectrometry (FAAS) was measured in fifty surface coastal sediment samples collected from 5 points coastal sediment of Bandar Abbas city, Iran besides the potential ecological risk index (RI) estimated the environmental health risk. The rank order of PTEs was Pb (52.090 ± 4.113 mg/kg dry weight) > Ni (34.940 ± 8.344 mg/kg dry weight) > Cd (2.944 ± 0.013 mg/kg dry weight). RI due to PTEs in sediments for A, B, C, D, and E points were 187.655, 190.542, 191.079, 189.496, and 192.053, respectively. RI for sampling points A to E was at moderate risk (150 ≤ RI < 300). Therefore, it is recommended to carry out control programs to reduce the amount of PTEs in the coastal sediment of the Persian Gulf.

Influence of subsoil and soil volume on the accumulation of nickel by Odontarrhena corsica grown on a serpentine soil.

Odontarrhena corsica was grown for three months on Chrome loam topsoil and subsoil from near Reisterstown, MD, to examine the effects of varying soil masses (2.8 and 5.6 kg pot-1) and soil layers (topsoil vs. subsoil) on plant growth and Ni accumulation. The subsoil position effect was simulated by placing a pot of topsoil on top of a pot filled with subsoil. Shoot Ni concentrations were similar for all treatments at 7 g Ni kg-1. Shoot yield was significantly higher in the 5.6 kg treatments compared to the 2.8 kg treatments (>18 g pot-1 vs. ∼12 g pot-1) and also greater in the topsoil treatment compared to the subsoil treatment (24.0 g pot-1 vs. 18.6 g pot-1), resulting in significantly higher phytomining. Soil depth had no statistically significant effect on shoot and root yield. Subsoil fertilization increased yield (25.8 g pot-1 vs. 19.7 g pot-1), enough to suggest that further research is warranted to optimize Ni phytomining. This study confirms the importance of soil volume and root access to the subsoil when evaluating the potential for Ni phytomining by Odontarrhena species. The use of small pots may lead to an underestimation of phytomining potential.

Prior studies have demonstrated that greater soil volume enhances Ni phytomining by Odontarrhena Ni hyperaccumulators. This study investigated Ni phytomining in both serpentine subsoil and topsoil, and examined the role of soil volume in this context. Our findings indicate that root access to Ni-rich serpentine subsoil significantly enhances Ni phytomining.