Respiratory cancer risks associated with low-level nickel exposure: an integrated assessment based on animal, epidemiological, and mechanistic data

Comprehensive review on toxic heavy metals in the aquatic system: sources, identification, treatment strategies, and health risk assessment

Heavy metal pollution in water sources has become a major worldwide environmental issue, posing a threat to aquatic ecosystems and human health. The pollution of the aquatic environment is increasing as a result of industrialization, climate change, and urban development. The sources of heavy metal pollution in water include mining waste, leachates from landfills, municipal and industrial wastewater, urban runoff, and natural events such as volcanism, weathering, and rock abrasion. Heavy metal ions are toxic and potentially carcinogenic. They can also buildup in biological systems and cause bioaccumulation even at low levels of exposure, heavy metals can cause harm to organs such as the nervous system, liver and lungs, kidneys and stomach, skin, and reproductive systems. There were various approaches tried to purify water and maintain water quality. The main purpose of this article was to investigate the occurrence and fate of the dangerous contaminants (Heavy metal and metalloids) found in domestic and industrial effluents. This effluent mixes with other water streams and is used for agricultural activities and other domestic activities further complicating the issue. It also discussed conventional and non-conventional treatment methods for heavy metals from aquatic environments. Conclusively, a pollution assessment of heavy metals and a human health risk assessment of heavy metals in water resources have been explained. In addition, there have been efforts to focus on heavy metal sequestration from industrial waste streams and to create a scientific framework for reducing heavy metal discharges into the aquatic environment.

Toxicological Aspects Associated with Consumption from Electronic Nicotine Delivery System (ENDS): Focus on Heavy Metals Exposure and Cancer Risk

Tobacco smoking remains one of the leading causes of premature death worldwide. Electronic Nicotine Delivery Systems (ENDSs) are proposed as a tool for smoking cessation. In the last few years, a growing number of different types of ENDSs were launched onto the market. Despite the manufacturing differences, ENDSs can be classified as "liquid e-cigarettes" (e-cigs) equipped with an atomizer that vaporizes a liquid composed of vegetable glycerin (VG), polypropylene glycol (PG), and nicotine, with the possible addition of flavorings; otherwise, the "heated tobacco products" (HTPs) heat tobacco sticks through contact with an electronic heating metal element. The presence of some metals in the heating systems, as well as in solder joints, involves the possibility that heavy metal ions can move from these components to the liquid, or they can be adsorbed into the tobacco stick from the heating blade in the case of HTPs. Recent evidence has indicated the presence of heavy metals in the refill liquids and in the mainstream such as arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), and lead (Pb). The present review discusses the toxicological aspects associated with the exposition of heavy metals by consumption from ENDSs, focusing on metal carcinogenesis risk.

Partition pattern and environmental consequences of the widespread coalmines and host rocks on the water of selected regions, China

The massive exploration and random dumping of coals in various regions of China create serious environmental and health problems because of the presence of toxic trace elements (TTEs), which possibly transfer to environment and cause serious health issues. This study was conducted to probe the environmental consequences of coalmines on the aquifer water and their association with health risks and the environment. For this purpose, 100 s of water samples was collected from the typical coalmine regions of Hancheng, Huanglong, Binxian, Handan, Langao, and Fusui and analyzed for various parameters. In Handan mining areas, Se, Mn, Fe, TDS, SO42-, and total hardness were higher than the WHO standard, while in Hancheng, SO42- was > 95%, Ca2+ 40-96%, and Mg2+ was 0-40%, which caused permanent hardness. In the Fusui and Huanglong areas, the SO42- concentration was > 95%, Ca2+ 60-100%, and Mg2+ 20%, causing permanent hardness. In Binxian, HCO3- was 70-90%, Ca2+ 60-80%, and Cl- and SO42- were 20%, causing temporary hardness. In the Kashin-Beck disease (KBD) area, Se in the Middle Triassic was 0.3, Upper Triassic 0.23, and Quaternary 0.01, while fluoride (F) was 124.7, 141.6, and 159 in μg L-1. The Handan water is included in rock-evaporation dominance (a mixed controlling mechanism), Hancheng, Binxian, Huanglong, and Langao water was included in rock dominance, while the Fusui water was included in rock-precipitation dominance. The average daily intake ((ADI) mg kg-1 d-1) of Ba, Cd, Co, Cr, Cu, Fe, Ti, Tl, Mo, Ni, Zn, Pb, Be, U, and Sr was comparably higher than No Observed Adverse Effect Level (NOAEL), which surely causes high health risk in selected regions. The elemental contaminants in the water were attributed to the geological environment, geochemical processes, ion exchanges, redox reactions, and dissolution of mineralized rock. For aquifer safety, coal mining, and other geological activities should be avoided to protect the water for future generations.

Nickel induces blood-testis barrier damage through ROS-mediated p38 MAPK pathways in mice

Nickel (Ni) is an essential common environmental contaminant, it is hazardous to male reproduction, but the precise mechanisms are still unknown. Blood-testis barrier (BTB), an important testicular structure consisting of connections between sertoli cells, is the target of reproductive toxicity caused by many environmental toxins. In this study, ultrastructure observation and BTB integrity assay results indicated that NiCl2 induced BTB damage. Meanwhile, BTB-related proteins including the tight junction (TJ), adhesion junction (AJ) and the gap junction (GJ) protein expression in mouse testes as well as in sertoli cells (TM4) were significantly decreased after NiCl2 treatment. Next, the antioxidant N-acetylcysteine (NAC) was co-treated with NiCl2 to study the function of oxidative stress in NiCl2-mediated BTB deterioration. The results showed that NAC attenuated testicular histopathological damage, and the expression of BTB-related proteins were markedly reversed by NAC co-treatment in vitro and vivo. Otherwise, NiCl2 activated the p38 MAPK signaling pathway. And, NAC co-treatment could significantly inhibit p38 activation induced by NiCl2 in TM4 cells. Furthermore, in order to confirm the role of the p38 MAPK signaling pathway in NiCl2-induced BTB impairment, a p38 inhibitor (SB203580) was co-treated with NiCl2 in TM4 cells, and p38 MAPK signaling inhibition significantly restored BTB damage induced by NiCl2 in TM4 cells. These results suggest that NiCl2 treatment destroys the BTB, in which the oxidative stress-mediated p38 MAPK signaling pathway plays a vital role.

Evaluation of trace metallic element levels in coffee by icp-ms: a comparative study among different origins, forms, and packaging types and consumer risk assessment

Trace elements (TE) contamination of foods and beverages constitutes a public health issue. In this context, the main objective of this study was to determine metals and metalloids content in coffee and to assess the health risks associated with contaminated coffee consumption. To this end, 44 samples of coffee from different origins, forms, and packaging types were analyzed. TE analysis was performed by ICP-MS after digestion. The data analysis was based on principal components analysis (PCA) and analysis of variance (ANOVA). Health risk assessment was determined by the estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI). The findings showed that TE levels in coffee varied widely. The highest levels were related to aluminum (Al) (59.88 ± 54.86 mg/kg), manganese (Mn) (16.26 ± 24.59 mg/kg), copper (Cu) (11.60 ± 11.55 mg/kg), and cadmium (Cd) (9.92 ± 10.32 mg/kg). In terms of coffee form and packaging type, a significant difference (P < 0.0001) was observed in nickel (Ni), chromium (Cr), zinc (Zn), cobalt (Co), Cu, Mn, and Al content. The highest EDI was found in Al (0.0109 mg/kg BW/day) in ground coffee packaged in capsules. In terms of chronic daily intake (CDI), Cd and Al were above the reference dose (RfD). THQ of these elements were greater than 1.0, and HI was above the value of 1.0 in different forms of coffee. More interdisciplinary research on the relationships between the metal concentrations in coffee samples and those in feed, water, and soil would be quite interesting.

Associations between serum trace elements and the risk of nasopharyngeal carcinoma: a multi-center case-control study in Guangdong Province, southern China

Background

Associations between trace elements and nasopharyngeal carcinoma (NPC) have been speculated but not thoroughly examined.

Methods

This study registered a total of 225 newly diagnosed patients with NPC and 225 healthy controls matched by sex and age from three municipal hospitals in Guangdong Province, southern China between 2011 and 2015. Information was collected by questionnaire on the demographic characteristics and other possibly confounding lifestyle factors. Eight trace elements and the level of Epstein-Barr virus (EBV) antibody were measured in casual (spot) serum specimens by inductively coupled plasma-mass spectrometry (ICP-MS) and enzyme-linked immunosorbent assay (ELISA), respectively. Restricted cubic splines and conditional logistic regression were applied to assess the relationship between trace elements and NPC risk through single-and multiple-elements models.

Results

Serum levels of chromium (Cr), cobalt (Co), nickel (Ni), arsenic (As), strontium (Sr) and molybdenum (Mo) were not associated with NPC risk. Manganese (Mn) and cadmium (Cd) were positively associated with NPC risk in both single-and multiple-element models, with ORs of the highest tertile compared with the reference categories 3.90 (95% CI, 1.27 to 7.34) for Mn and 2.30 (95% CI, 1.26 to 3.38) for Cd. Restricted cubic splines showed that there was a linear increasing trend between Mn and NPC risk, while for Cd there was a J-type correlation.

Conclusion

Serum levels of Cd and Mn was positively related with NPC risk. Prospective researches on the associations of the two trace elements with NPC ought to be taken into account within the future.

How Does Environmental and Occupational Exposure Contribute to Carcinogenesis in Genitourinary and Lung Cancers?

Environmental and occupational exposures have been associated with an increased risk of different types of cancers, although the exact mechanisms of higher carcinogenesis risk are not always well understood. Lung cancer is the leading cause of global cancer mortality, and, also, genitourinary neoplasms are among the main causes of cancer-related deaths in Western countries. The purpose of this review is to describe the main environmental and occupational factors that increase the risk of developing lung and genitourinary cancers and to investigate carcinogenesis mechanisms that link these agents to cancer onset. Further objectives are to identify methods for the prevention or the early detection of carcinogenic agents and, therefore, to reduce the risk of developing these cancers or to detect them at earlier stages.

Synthesis of a quinoxaline-hydrazinobenzothiazole based probe-single point detection of Cu2+, Co2+, Ni2+ and Hg2+ ions in real water samples

A novel quinoxaline-hydrazinobenzothiazole based sensor was synthesized and characterized using NMR, FTIR, and Mass spectroscopy techniques. The sensor achieves the distinct "single-point" colorimetric and fluorescent detection of Cu²⁺, Co²⁺, Ni²⁺ and Hg²⁺ ions with distinguishable color changes from yellow to red, pale red, pale brown and orange, respectively. The UV-visible and fluorescence emission spectral investigation revealed the excellent single-point sensing ability of the probe towards four different heavy metal ions with a ratiometric response. Nanomolar levels of detection of about 1.16 × 10^-7 M, 9.92 × 10^-8 M, 8.21 × 10^-8 M, and 1.14 × 10^-7 M for Cu²⁺, Co²⁺, Ni²⁺ and Hg²⁺ ions, respectively, were achieved using our sensor, which are below the US-EPA permissible limits. Additionally, the sensor was utilized for naked eye detection under normal daylight. Quantitative determination of the metal ions in real water samples was also demonstrated.

Trace elements in Foodstuffs from the Mediterranean Basin-Occurrence, Risk Assessment, Regulations, and Prevention strategies: A review

Trace elements (TEs) are chemical compounds that naturally occur in the earth's crust and in living organisms at low concentrations. Anthropogenic activities can significantly increase the level of TEs in the environment and finally enter the food chain. Toxic TEs like cadmium, lead, arsenic, and mercury have no positive role in a biological system and can cause harmful effects on human health. Ingestion of contaminated food is a typical route of TEs intake by humans. Recent data about the occurrence of TEs in food available in the Mediterranean countries are considered in this review. Analytical methods are also discussed. Furthermore, a discussion of existing international agency regulations will be given. The risk associated with the dietary intake of TEs was estimated by considering consumer exposure and threshold values such as Benchmark dose lower confidence limit and provisional tolerable weekly intake established by the European Food Safety Authority and the Joint FAO/WHO Expert Committee on Food Additives, respectively. Finally, several remediation approaches to minimize TE contamination in foodstuffs were discussed including chemical, biological, biotechnological, and nanotechnological methods. The results of this study proved the occurrence of TEs contamination at high levels in vegetables and fish from some Mediterranean countries. Lead and cadmium are more abundant in foodstuffs than other toxic trace elements. Geographical variations in TE contamination of food crops clearly appear, with a greater risk in developing countries. There is still a need for the regular monitoring of these toxic element levels in food items to ensure consumer protection.

Inhalable mixture of polycyclic aromatic hydrocarbons and metals, DNA oxidative stress and nasal ribosomal DNA copy number amplification: Direct and indirect effect analyses among population

The ribosomal DNA (rDNA) plays a crucial role in maintaining genome stability. So far, alterations of rDNA from airborne pollutants exposure remain unclear. Nasal epithelial cells are the earliest respiratory barrier, which has an accessible surrogate for evaluating respiratory impairment. We developed a mixture-centered biomarkers study integrated epidemiological and biological evidence among 768 subjects, a mixture of polycyclic aromatic hydrocarbons (PAHs) and metals. We identified the mixed exposure of PAHs and metals by environmental and biological monitoring, selected urinary 8-hydroxy-2'-deoxyguanosine as DNA oxidative stress marker, and measured their rDNA copy number (rDNA CN) in nasal epithelial cells. We performed linear regression, adaptive elastic net regression, BKMR, and mediation analyses to assess the direct and indirect effects. We found a 10% elevation in urinary 1-hydroxypyrene was correlated with a separate 0.31% and 0.82% amplification of nasal 5S and 45S rDNA CN, respectively (all P < 0.05). A 10% increment of urine nickel was associated with a separate 0.37% and 1.18% elevation of nasal 5S and 45S rDNA CN, respectively (all P < 0.05). BKMR results also confirmed our findings of PAHs and nickel. Our findings suggested that DNA oxidative stress might trigger rDNA instability induced by inhaled PAHs and metals.

Optimization of the effect of microelectrodes on Ni2+ removal in three-dimensional electrode system

This study investigated Ni⁺² removal performance in 3DER reactors where electrocoagulation mechanisms and microelectrodes are used together. EDTA modification was carried out on the granule-activated carbon surface to increase the efficiency and affinity of microelectrodes against Ni⁺² molecules. The grafting was examined using BET, FT-IR, SEM, EDS, and the elemental mapping methods. With the surface analyses made in this study, it was revealed that EDTA modification on granulated activated carbon was successfully performed. Also, 8.48%wt by mass of EDTA grafting on granular activated carbon was possible. EDTA functionalization did not affect the surface pore structures of CAC much. Under 10 V potential, 97.82% Ni removal efficiency was obtained with 2D in 35 min, while 96.69% removal in 10 min and 100% removal in 15 min were obtained in the 3D reactor. The Ni⁺² removal mechanism in 3DER reactors has been determined to conform to the pseudo-second-order kinetic model. The k₂ value obtained for 10 V (1.36 10^-2) is 27 times the k₂ value obtained for 5 V for 3DER reactors. In addition, using central composite design (CCD), operational parameters such as time, concentration, and potential difference affecting Ni⁺² removal in 3DER reactors have been optimized. The most influential parameter is the applied voltage, followed by time and concentration. It has been determined that 3DER reactors using EDTA-modified microelectrodes are highly efficient and suitable for Ni⁺² removal.

"Assessing exposure of printing factory workers in thailand to selected heavy metals using urine and hair as non-invasive matrices"

BACKGROUND

There are few thorough studies on the extent and inter-element relationships of heavy metal contamination in printing factory workers, especially in developing countries. The objective of this study was to determine the levels of eight heavy metals, including arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), cobalt (Co), lead (Pb), mercury (Hg), and manganese (Mn), in urine and scalp hair of printing industry workers, and assess inter-element correlations.

METHODS

We examined a total of 85 urine samples and 85 scalp hair samples (3 cm hair segments taken from near the scalp) in 85 printing workers from a printing house in Bangkok, Thailand. We used an interviewer-administered questionnaire about participants' printing techniques, work characteristics, and work environment. Urine and scalp hair samples were analyzed for levels of each element using the inductively coupled plasma optical emission spectrometry (ICP-OES) technique.

RESULTS

As, Cd, Cr, Ni, Pb were detected in urine with the geometric mean concentration range of 0.0028-0.0209 mg/L, and Hg, Pb, Ni, Cd, Co, Mn, Cr were detected in hair samples (0.4453-7.165 mg/kg dry weight) of printing workers. The geometric mean Ni level was significantly higher in the urine of production line workers than back-office personnel (0.0218 mg/L vs. 0.0132 mg/L; p = 0.0124). The other elements did not differ significantly between production line and back-office workers in either urine or hair. There was also a strong, statistically significant positive correlation between Ni and Co levels in hair samples of workers (r = 0.944, p < 0.0001).

CONCLUSIONS

Average concentrations of most of the metals in urine and hair of printing workers were found to be above the upper reference values. The significantly higher concentrations of Ni in production line workers might be due to more exposure to printed materials. A strong inter-element correlation between Ni and Co in hair samples can increase stronger health effects and should be further investigated. This study reveals possible dependencies and impact interactions of heavy metal exposure in printing factory workers.

Potentially toxic elements exposure biomonitoring in the elderly around the largest polymetallic rare earth ore mining and smelting area in China

Potentially toxic elements (PTEs) can be released during mining operations and ore processing. The pollution and health risk related to PTEs in total suspended particulates (TSPs) around the largest polymetallic rare earth mining area (Bayan Obo) and smelting area (Baotou) in Inner Mongolia, China, were evaluated. PTEs in the hair of the elderly living in these two areas and a reference area (Hohhot) were also examined. Relationships between PTEs in TSPs and hair with categorical factors (location, gender, etc.) were also modeled. Multivariate statistical analyses were carried out to analyze the possible sources of the PTEs in TSPs. The bubble maps of the concentrations of PTEs indicated that high concentrations of PTEs were near the industrial area where smelting plants and power plants were located. In addition, health risks were assessed for adults in the mining and smelting area. The carcinogenic risk of Cr was high for residents in the study areas. Also, the residents were exposed to a non-carcinogenic risk of Ni. Significant mean value differences were observed between PTEs in the hair of the elderly in Baotou and Hohhot. Results of the linear regression model indicated that around 31 % of the Pb in hair could be explained by the linear regression model, it could be affected by Ni and Zn in TSPs, but location, gender, and sampling time showed no significant contribution. Age was not significantly associated with the PTEs levels in hair in Baotou and Bayan Obo. The results provide important scientific evidence for a better understanding of the effects of PTEs in TSPs in polymetallic ore mining and smelting areas.

Seasonal changes and respiratory deposition flux of PM2.5 and PM10 bound metals in Dhaka, Bangladesh

Due to rapid urbanization and fast economic development, aerosol pollution is a serious environmental issue, especially in Bangladesh. Based on bioaccessibility and respiratory deposition doses (RDD), health risks of PM_2.5 and PM₁₀ bound 15 (fifteen) metals were investigated at fourteen urban sites (roadside, marketplace, industrial, and commercial areas). Sampling campaigns were conducted over four seasons (winter, summer, rainy, and autumn) from December 2020 to November 2021. A beta attenuation mass analyzer measured particulate matter concentrations in ambient air. The metals in PM fractions were analyzed by X-ray fluorescence spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). The airborne trace metals (Cd, As, Zn, Pb, Cr, Cu, Ni) with high enrichment factors indicate anthropogenic sources. The positive matrix factorization (PMF) categorized these elements as originating from automobile exhaust, industrial emissions, and solid waste/coal combustion, whereas the geologic elements came from earth crust/soil dust. During the winter, most of the air mass trajectories arrived from India across the land (82%) and Indo Gangetic Plain (IGP) region to the sampling sites, which may have aided in the transport of pollutants. The deposition flux of metals illustrated that compared to PM_2.5, PM₁₀ deposited a higher amount of metals in the upper airways (81.96%). In comparison, PM_2.5 accumulates more elevated amounts of metals in alveolar regions (11.77%), due to the ability of fine particles to penetrate deeper into the lower pulmonary region. Among age groups, an adult inhales a higher amount of metals than a child, on average 0.103 mg and 0.08 mg of metals per day via PM_2.5, respectively. Acute health impacts are caused by the deposited cancer-causing metals in alveolar tissue, which circulates through the bloodstream and affects several organs. Prolonged exposure to these carcinogenic metals poses significant health risks.

Investigation of nickel sulfate-induced cytotoxicity and underlying toxicological mechanisms in human umbilical vein endothelial cells through oxidative stress, inflammation, apoptosis, and MAPK signaling pathways

Growing evidence indicates that nickle and its compounds have adverse effects on the cardiovascular system. In this study, the cytotoxic insults caused by nickel sulfate (NiSO₄ ) in human umbilical vein endothelial cells (HUVECs) were explored by examining cell viability, oxidative stress, inflammation, apoptosis, and MAPK signaling pathway activity. Cultured HUVECs were treated with varying concentrations of NiSO₄ (0, 62.5, 250, and 1000 μM) for 24 h. Subsequently, markers of oxidative stress, inflammation, apoptosis, and MAPK signaling pathways were analyzed using biochemical assays, real-time quantitative polymerase chain reaction, and western blot. Rates of apoptosis were evaluated using flow cytometry. The results showed that NiSO₄ exerted dose- and time-dependent inhibitory effects on cell growth. It induced oxidative stress and lipid peroxidation by increasing the generation of reactive oxygen species, the oxidized glutathione to reduced glutathione ratio (GSSG/GSH ratio), and malondialdehyde levels. Further, it inhibited superoxide dismutase activity in HUVECs. Flow cytometry analysis results revealed that NiSO₄ (62.5-1000 μM) could induce apoptosis in HUVECs. The protein and gene expressions of cleaved Caspase 3 and Bax were elevated, and those of Bcl-2 and Bcl-XL were reduced after NiSO₄ treatment. Additionally, NiSO₄ triggered inflammation in HUVECs, increasing the protein and mRNA levels of IL-6 and TNF-α and reducing those of TGF-β. Furthermore, western blot findings revealed that NiSO₄ could activate MAPK signaling pathways, upregulating p38, JNK, and ERK1/2 in HUVECs by increasing the levels of p-P38，p-JNK, and p-ERK1/2 in a dose-dependent manner. MAPK pathway inhibitors (10 μM SB203580 and 10 μM SP600125) could attenuate the NiSO₄ -induced increase in apoptosis and inflammation in HUVECs. They could also attenuate the dysregulation of inflammatory factors and related proteins caused by high-dose NiSO₄ exposure. Interestingly, while the MEK inhibitor U0126 (10 μM) enhanced NiSO₄ -induced apoptosis in HUVECs, it reduced cell inflammation. Taken together, these experimental results suggest that NiSO₄ can inhibit cell growth, induce oxidative stress, and trigger subsequent inflammatory responses and apoptosis in HUVECs. These effects may be mediated by the P38 and JNK MAPK stress response pathways.

Toxic metals in the regulation of epithelial-mesenchymal plasticity: demons or angels?

Epithelial cells can trans-differentiate into motile mesenchymal cells through a dynamic process known as epithelial-mesenchymal transition (EMT). EMT is crucial in embryonic development and wound healing but also contributes to human diseases such as organ fibrosis and cancer progression. Heavy metals are environmental pollutants that can affect human health in various ways, including causing cancers. The cytotoxicity and carcinogenicity of heavy metals are complex, and studies have demonstrated that some of these metals can affect the progress of EMT. Here, we focus on reviewing the roles of six environmentally common toxic metals concerning EMT: arsenic (AS), cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni), and copper (Cu). Noteworthily, the effects of these elements on EMT may vary according to the form, dose, and exposure time; the dual role of heavy metals (e.g., AS, Cd, and Cu) on EMT is also observed, in which, sometimes they can promote while sometimes inhibit the EMT process. Given the vast number of toxicologically relevant metals that exist in nature, we believe a comprehensive understanding of their effects on EMT is required to dictate in what circumstances these metals act more likely as demons or angels.

Serum trace element levels of gastrointestinal cancer patients in an endemic upper gastrointestinal cancer region

Gastrointestinal (GI) cancers are an important cause of the death rate in Turkey and in the world. Especially upper (esophageal and gastric) GI cancers are the leading types of cancer by 20-27% in Eastern Turkey. Trace elements are involved in many physiological and metabolic processes in the human body. Recent studies suggest that the increase or decrease of trace elements in the body may be related to the formation and development of many diseases such as cancers, diabetes mellitus and cardiovascular diseases etc. METHOD AND MATERIALS: In this study some trace elements; cadmium (Cd), cobalt (Co), Copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn) concentrations were investigated in the blood serums of esophageal, gastric and colon cancer patients and healthy controls in Van city area, an endemic upper (esophageal and gastric) GI region of Eastern Turkey. The analysis of the elements was realized with a flame atomic absorption spectrophotometer (FAAS). RESULTS: Mean serum levels of Cd and Ni in esophageal and gastric cancer patients were very significantly lower compared to controls (p < 0.001 and < 0.005). In addition, the mean serum Co level of esophageal cancer patients was very significantly lower than in controls and gastric cancer patients (p < 0.002). Also, the mean serum levels of Fe and Mn in all (esophageal, gastric and colon) cancer groups were very significantly lower than in controls (p < 0.001 and 0.002). Mean serum levels of Cu, Mg, Pb and Zn were not significantly different in all cancer patients compared to controls. CONCLUSION: We have detected the deficiency of five trace elements (Fe, Mn, Cd, Ni, Co) in esophageal, gastric and colon cancer patients. The deficiencies of trace elements may be due to malign over consumption of the nutrients and to the malnutrition of the advanced cancer patients. Nutritional therapy rich in trace elements should be considered as one of the strategies to fight against cancers.

Plasma Nickel Levels Correlate with Low Muscular Strength and Renal Function Parameters in Patients with Prostate Cancer

Nickel is associated with cancer in occupational exposure. However, few studies have been devoted to analyzing the effects of nickel at environmental concentrations in cancer patients. In this work, the concentration of nickel in blood samples from patients with prostate cancer (PCa) was evaluated because this metal displays androgenic and estrogenic effects that play a crucial role in prostate carcinogenesis and treatment. We, therefore, compared blood nickel concentration in patients with PCa (non-occupationally exposed) (n = 46) with those in control age-matched individuals (n = 46). We also analyzed if there was any association between sociodemographic factors, clinical variables, geriatric evaluation assessment results, blood cell counts, or biochemical, androgen and estrogen concentrations. Using inductively coupled plasma-mass spectroscopy on the plasma samples, we observed a mean nickel level of 4.97 ± 1.20 µg/L in the PCa group and 3.59 ± 0.49 µg/L in the control group, with a non-significant effect (p = 0.293) between the two groups. The nickel concentration was significantly correlated with patient age (p = 0.005) and reduced handgrip strength (p = 0.003). Regarding biochemical parameters, significant associations were found with the renal glomerular filtration rate (p = 0.024) and blood urea levels (p = 0.016). No significant correlations were observed with other blood analytical parameters or testosterone or estradiol levels. These specific renal function and muscle strength effects were observed at environmental nickel exposure levels believed to be safe or at least far from the high concentrations observed after occupational exposure. Therefore, these parameters deserve further study, given that they could help pinpoint further public health concerns regarding nickel exposure in the general population.

Evaluating the Potential Health Risks of Selected Heavy Metals across Four Wastewater Treatment Water Works in Durban, South Africa

Poor and inadequate sanitation systems have been considered not only a human health issue, but also an environmental threat that instigates climate change. Nine heavy metals-arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn)-were evaluated in influent and effluent water samples from four wastewater treatment plants in the Durban metropolis, KwaZulu-Natal, South Africa. The results indicate that the mean concentrations of all the heavy metals in the influent samples ranged from 0.122 to 1.808 mg/L, while the effluent samples had a concentration ranging from 0.118 to 0.854 mg/L. Iron was found to be in the highest concentration and the concentration of Co was the lowest across the wastewater treatment plants. The levels for most of the heavy metals in this study were found to be above the recommended maximum concentrations in surface and effluent waters as stipulated by the World Health Organization, United States Environmental Protection Agency, Food and Agriculture Organization, and the Department of Water Affairs and Forestry of South Africa. According to the toxicity effect due to non-carcinogenic risks, As, Pb, Cr, and Cd are considered to be of medium risk in this study, indicating that a probable adverse health risk is very likely to occur. Additionally, the cancer risk (RI) values were lower than 10^-3, which shows that cancer development is very likely in individuals who are exposed. Cancer development associated with dermal absorption is quite negligible; thereby, it does not raise any concerns.

Biomonitoring of Urinary Nickel Successfully Protects Employees and Introduces Effective Interventions

Nickel is a heavy metal used in many industries. Nickel exposure can induce respiratory diseases and allergic reactions, and increase cancer risk. This study evaluated the introduction of a grinding and polishing system to prevent injuries from nickel toxicity in workers. We performed a controlled, interventional, before-and-after study from January 2018 to December 2019 at a faucet component industrial manufacturing site. Results from workplace environmental monitoring, questionnaire responses, and biomonitoring were collected before and after the intervention. Thirty-seven workers (100% men) aged 25.0 (interquartile range (IQR): 22.0–33.5) years were categorized into two groups, those with and without nickel exposure. In the exposed group, the median exposure time was 18.0 months (IQR 14.0–20.0 months). Urinary nickel concentration was lower in the exposed group than in the non-exposed group (13.8 (IQR 1.7–20.7); 23.1 (IQR 11.3–32.8) μg/g creatinine, respectively; p = 0.047). The median urinary nickel concentration was lower in the second year than in the first year (17.4 (IQR 2.2–27.4), 7.7 (IQR 4.3–18.5) μg/g creatinine, respectively; p = 0.022). Significant reductions in urinary nickel concentration were observed following the intervention and educational program. Thus, biomonitoring of urinary nickel concentration can successfully reflect the effectiveness of interventions and their relationship to nickel exposure.

Comparative Study of Potentially Toxic Nickel and Their Potential Human Health Risks in Seafood (Fish and Mollusks) from Peninsular Malaysia

Human exposure to highly nickel (Ni)-polluted environments through oral ingestion pathways may cause various pathological effects. This biomonitoring study aimed to assess the human health risk of potentially toxic Ni in 19 species of marine fishes from Setiu (Terengganu) and two popular seafood molluscs (mangrove snail Cerithidea obtusa and cockle Anadara granosa) from the coastal area of Peninsular Malaysia. The Ni levels of the three seafood types were found below the maximum permissible limit for Ni. The Ni target hazard quotient values of all seafood were lower than 1.00 for average and high-level (AHL) Malaysian consumers, indicating no Ni's non-carcinogenic risk of seafood consumption. It was also found that the calculated values of estimated weekly intake were below than established provisional tolerable weekly intake of Ni for both AHL consumers. It can be concluded that both the AHL consumption of seafood would not pose adverse effects of Ni to the consumers. This study provided a scientific basis for the food safety assessment of Ni and suggestions for risk management of potentially toxic Ni of seafood consumption in Malaysia.

Heavy Metal Contamination of Natural Foods Is a Serious Health Issue: A Review

Heavy metals play an important role in the homeostasis of living cells. However, these elements induce several adverse environmental effects and toxicities, and therefore seriously affect living cells and organisms. In recent years, some heavy metal pollutants have been reported to cause harmful effects on crop quality, and thus affect both food security and human health. For example, chromium, cadmium, copper, lead, and mercury were detected in natural foods. Evidence suggests that these elements are environmental contaminants in natural foods. Consequently, this review highlights the risks of heavy metal contamination of the soil and food crops, and their impact on human health. The data were retrieved from different databases such as Science Direct, PubMed, Google scholar, and the Directory of Open Access Journals. Results show that vegetable and fruit crops grown in polluted soil accumulate higher levels of heavy metals than crops grown in unpolluted soil. Moreover, heavy metals in water, air, and soil can reduce the benefits of eating fruits and vegetables. A healthy diet requires a rational consumption of foods. Physical, chemical, and biological processes have been developed to reduce heavy metal concentration and bioavailability to reduce heavy metal aggregation in the ecosystem. However, mechanisms by which these heavy metals exhibit their action on human health are not well elucidated. In addition, the positive and negative effects of heavy metals are not very well established, suggesting the need for further investigation.

Impacts of the linear flowing industrial wastewater on the groundwater quality and human health in Swabi, Pakistan

The present study aimed to probe the extent and mobility of contamination in wastewater and its impact on groundwater and human health in the Swabi region in Pakistan. Representative samples (n = 86) were collected from both wastewater streams and groundwater in an analogous environmental setting. The result showed that pH, color, hardness, alkalinity, chemical oxygen demand, chloride, suspended solids, total dissolved solids, Cr, Cd, Pb, Cu, Fe, Mg, Na, Ca, and K in industrial wastewater were higher than the Pak-EPA (Pakistan Environmental Protection Agency) and the United State Environmental Protection Agency (US-EPA) devised standards. In groundwater, the concentration (μg L^-1) of trace elements, namely, Cd (1.16), Pb (17.4), Fe (12426), Mn (320), Mg (129784), Na (33630), Ca (177944), and K (9558) was significantly higher than the WHO (World Health Organization) acceptable level, showing decreasing tendency with increasing distance from the industrial zone. The study perceived that wastewater caused permanent hardness, while groundwater hardness was decreased from permanent to temporary at a distance from industries. Integrated health risk assessment revealed that Cu, Zn, and Co may cause low risk, Na, Mn, Ni, Pb, and Cr cause medium risk, whereas Cd, Fe, Mg, Ca, and K may cause a high health risk. Moreover, the average daily intake of Fe, Mn, Mg, Na, Ca, and K was comparably higher than Cr, Cd, Pb, Ni, Cu, Zn, and Co in both adults and children. The mode of occurrence of contaminants in groundwater was due to the leaching of contaminated wastewater and the oxidation of metals. Furthermore, carbonates, chloride, and SAR (sodium adsorption ratio) precipitation have a key role in groundwater contamination and influencing the natural water quality. The study concluded that the health problems in the surrounding areas were due to the use of contaminated water for drinking and household purpose. The study suggests filtering the drinking water and treating the wastewater before releasing it into the environment.

Nickel in terrestrial biota: Comprehensive review on contamination, toxicity, tolerance and its remediation approaches

Nickel (Ni) has been a subject of interest for environmental, physiological, biological scientists due to its dual effect (toxicity and essentiality) in terrestrial biota. In general, the safer limit of Ni is 1.5 μg g^-1 in plants and 75-150 μg g^-1 in soil. Litreature review indicates that Ni concentrations have been estimated up to 26 g kg^-1 in terrestrial, and 0.2 mg L^-1 in aquatic resources. In case of vegetables and fruits, mean Ni content has been reported in the range of 0.08-0.26 and 0.03-0.16 mg kg^-1. Considering, Ni toxicity and its potential health hazards, there is an urgent need to find out the suitable remedial approaches. Plant vascular (>80%) and cortical (<20%) tissues are the major sequestration site (cation exchange) of absorbed Ni. Deciphering molecular mechanisms in transgenic plants have immense potential for enhancing Ni phytoremediation and microbial remediation efficiency. Further, it has been suggested that integrated bioremediation approaches have a potential futuristic path for Ni decontamination in natural resources. This systematic review provides insight on Ni effects on terrestrial biota including human and further explores its transportation, bioaccumulation through food chain contamination, human health hazards, and possible Ni remediation approaches.

RUNX2/miR‑31/SATB2 pathway in nickel‑induced BEAS‑2B cell transformation

Nickel (Ni) compounds are classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) and are known to be carcinogenic to the lungs. In our previous study, special AT‑rich sequence‑binding protein 2 (SATB2) was required for Ni‑induced BEAS‑2B cell transformation. In the present study, a pathway that regulates the expression of SATB2 protein was investigated in Ni‑transformed BEAS‑2B cells using western blotting and RT‑qPCR for expression, and soft agar, migration and invasion assays for cell transformation. Runt‑related transcription factor 2 (RUNX2), a master regulator of osteogenesis and an oncogene, was identified as an upstream regulator for SATB2. Ni induced RUNX2 expression and initiated BEAS‑2B transformation and metastatic potential. Previously, miRNA‑31 was identified as a negative regulator of SATB2 during arsenic‑induced cell transformation, and in the present study it was identified as a downstream target of RUNX2 during carcinogenesis. miR‑31 expression was reduced in Ni‑transformed BEAS‑2B cells, which was required to maintain cancer hallmarks. The expression level of miR‑31 was suppressed by RUNX2 in BEAS‑2B cells, and this increased the expression level of SATB2, initiating cell transformation. Ni caused the repression of miR‑31 by placing repressive marks at its promoter, which in turn increased the expression level of SATB2, leading to cell transformation.

The Warburg effect promoted the activation of the NLRP3 inflammasome induced by Ni-refining fumes in BEAS-2B cells

Nickel (Ni) is a known human carcinogen that has an adverse effect on various human organs in occupational workers during Ni refinement and smelting. In the present study, we used real-time polymerase chain reactions, Western blot analysis, and a lactate production assay to investigate whether an increase in the NLRP3 inflammasome induced by Ni-refining fumes was associated with the Warburg effect in BEAS-2B cells, a nonmalignant pulmonary epithelial line. Exposure to Ni-refining fumes suppressed cell proliferation and increased lactate production compared with those in an untreated control group in a dose- and time-dependent manner. Ni-refining fumes induced the Warburg effect, which was observed based on increases in the levels of hypoxia-inducible factor-1α, hexokinase 2, pyruvate kinase isozyme type M2, and lactate dehydrogenase A. In addition, Ni-refining fumes promoted increased expression of NLRP3 at both the gene and protein levels. Furthermore, inhibition of the Warburg effect by 2-Deoxy-d-glucose reversed the increased expression of NLRP3 induced by Ni-refining fumes. Collectively, our data demonstrated that the Warburg effect can promote the expression of the NLRP3 inflammasome induced by the Ni-refining fumes in BEAS-2B cells. This indicates a new phenomenon in which alterations in energy production in human cells induced by Ni-refining fumes regulate the inflammatory response.

Exogenous hydrogen sulfide donor NaHS alleviates nickel-induced epithelial-mesenchymal transition and the migration of A549 cells by regulating TGF-β1/Smad2/Smad3 signaling

Nickel compounds are known to be common environmental and occupational carcinogens which also promote the migration of lung cancer cells. However, the molecular mechanism yet remains to be clarified. Hydrogen sulfide (H₂S) is involved in cancer biological processes. However, the exact effect and functionality of H₂S on nickel, towards the promotion of the migration ability of lung cancer cells, remains to be unknown. In this study, we have found that the nickel chloride (NiCl₂) treatment significantly downregulates the protein levels of endogenous H₂S enzyme cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-Mercaptopyruvate sulfurtransferase (3-MST). A correlation between NiCl₂-induced epithelial-mesenchymal transition (EMT) and the migration ability of lung cancer A549 cells has been observed. Exogenous H₂S donor, sodium hydrogen sulfide (NaHS) (100 μmol/L), can reverse NiCl₂-induced EMT as well as the migration ability of A549 cells. NiCl₂ treatment is able to upregulate the protein level of transforming growth factor-β1 (TGF-β1), p-Smad2, p-Smad3, p-JNK, p-ERK and p-P38 in a time-dependent fashion, indicating that both TGF-β1/Smad2/Smad3 and mitogen-activated protein kinase (MAPK) signaling cascades (a non-Smad pathway) may play essential roles in NiCl₂-dependent EMT as well as cell migration of human lung cancer cells. Furthermore, exogenous NaHS alleviates the NiCl₂-induced EMT and the migration ability of A549 cells only by regulating TGF-β1/Smad2/Smad3, rather than the MAPK, signaling pathway. These results indicate that the exogenous administration of NaHS might be a potential therapeutic strategy against nickel-induced lung cancer progression.

Levels of heavy metals in wastewater and soil samples from open drainage channels in Nairobi, Kenya: community health implication

Levels of Mercury (Hg), Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni) & Thallium (Tl) were established in wastewater & soil samples obtained from 8 sites in open drainage channels at Nairobi industrial area, Kenya. Ultra-trace inductively coupled plasma mass spectroscopy (ICP-MS) was used for metal analysis. Temperature, pH & turbidity of wastewater ranged from 16.75 to 26.05 °C; 7.28 to 8.78; 160.33 to 544.69 ppm respectively and within World Health Organization (WHO) allowable limits. Wastewater conductivities in 4 sites ranged from 770 to 1074 µS/cm and above WHO limits at 25 °C. The mean concentrations of the metals in wastewater ranged from 0.0001 to 0.015 ppm in an ascending order of Tl <Cd <Hg <Ni <Cr <Pb. Levels of Cd, Cr & Ni in wastewater were within WHO, World Bank (WB), United States Environmental Protection Agency (US EPA), China, Kenya and India’s Central Pollution Control Board (CPCB) limits while Hg & Tl were above US EPA limits. The mean Pb levels in wastewater (5 sites) were above WHO, US EPA and Kenya allowable limits. Mean levels of the metals in soil samples ranged from 0.085 to 199.99 ppm, with those of Hg, Pb, Cr, Cd & Ni being above WHO limits for agricultural soils. Positive correlations (P < 0.05) for Cd & Hg in soils; and Tl (wastewater) & Cd (soil) were noted. In conclusion, wastewater in open waste channels at Nairobi industrial area had elevated levels of Pb and Hg, while the soil from the same channels had high levels of Hg, Pb, Ni, Cr, and Cd. Good management of Nairobi industrial area effluents is inevitable since it borders densely populated informal settlements which are likely to suffer exposure to toxic wastes. Effective wastewater treatment and reuse is highly recommended.

Mineralogical and Geochemical Characterization of Asbestiform Todorokite, Birnessite, and Ranciéite, and Their host Mn-Rich Deposits from Serra D’Aiello (Southern Italy)

Manganese ores, especially the oxyhydroxides in their different forms, are the dominant Mn-bearing minerals that occur in marine and terrestrial environments, where they are typically found as poorly crystalline and intermixed phases. Mn oxyhydroxides have a huge range of industrial applications and are able to exert a strong control on the mobility of trace metals. This paper reports the results of a detailed study on the Mn oxyhydroxides occurring in the manganiferous deposit outcropping in the Messinian sediments from Serra D’Aiello (Southern Italy). Nine Mn samples were characterized in detail using X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), thermogravimetry (TG), transmission electron microscopy combined with energy dispersive spectrometry (TEM/EDS), and X-ray fluorescence (XRF). The results indicated that the Mn deposit included the oxyhydroxide mineral species birnessite, todorokite, and rancièite. The size, morphology, and chemical composition of Mn oxyhydroxide samples were investigated in order to define their impact on the environment and human health. Todorokite displayed asbestiform shapes and could disperse fibers of breathable size in the air. Furthermore, since in-depth characterization of minerals within Mn deposits may be the first step toward understanding the genetic processes of manganese deposits, hypotheses about the genesis of the Mn oxyhydroxide deposits were discussed.

Nickel: Human Health and Environmental Toxicology

Nickel is a transition element extensively distributed in the environment, air, water, and soil. It may derive from natural sources and anthropogenic activity. Although nickel is ubiquitous in the environment, its functional role as a trace element for animals and human beings has not been yet recognized. Environmental pollution from nickel may be due to industry, the use of liquid and solid fuels, as well as municipal and industrial waste. Nickel contact can cause a variety of side effects on human health, such as allergy, cardiovascular and kidney diseases, lung fibrosis, lung and nasal cancer. Although the molecular mechanisms of nickel-induced toxicity are not yet clear, mitochondrial dysfunctions and oxidative stress are thought to have a primary and crucial role in the toxicity of this metal. Recently, researchers, trying to characterize the capability of nickel to induce cancer, have found out that epigenetic alterations induced by nickel exposure can perturb the genome. The purpose of this review is to describe the chemical features of nickel in human beings and the mechanisms of its toxicity. Furthermore, the attention is focused on strategies to remove nickel from the environment, such as phytoremediation and phytomining.

Phytoremediation Potential of Macrophytes of Urban Waterbodies in Central India

BACKGROUND

India's rapidly increasing population and growing urbanization pose a great challenge for wastewater treatment efforts, leading to increased pollution of surrounding waterbodies.

OBJECTIVES

A field sampling-based study was conducted to analyze water quality, heavy metals and bioconcentration and bioaccumulation in the roots and shoots of naturally growing vegetation in an urban lake, Laxmi Taal. The lake receives domestic sewage from Jhansi city in Central India.

METHODS

Temperature, pH, electrical conductivity, turbidity, and water-soluble ions were measured with appropriate instruments. Plant accumulation of metals was measured with the bioconcentration factor (BCF), the ratio of metal concentration in the root to wastewater. The translocation factor (TF) was estimated as the ratio of metal concentration in the shoot to the root.

RESULTS

Water quality and heavy metal concentrations were found to be within the prescribed limit as per Indian standards IS-2296 "D". In the present study, BCF was assessed to be >1 and the plants Typha angustifolia and Echhornia crassipus were determined to be accumulator plants. The TF study revealed that translocation of all the metals studied were significant, except for manganese (Mn), where concentration was found to be below detection limit.

CONCLUSIONS

The present study validated that Typha angustifolia and Echhornia crassipus could be used for bioremediation purposes in cases of urban waterbodies receiving varying amounts of domestic wastewaters which have relatively limited concentrations of toxic metals.

COMPETING INTERESTS

The authors declare no competing financial interests.

The Role of Non-Coding RNAs Involved in Nickel-Induced Lung Carcinogenic Mechanisms

Nickel is a naturally occurring element found in the Earth’s crust and an International Agency for Research on Cancer (IARC)-classified human carcinogen. While low levels found in the natural environment pose a minor concern, the extensive use of nickel in industrial settings such as in the production of stainless steel and various alloys complicate human exposure and health effects. Notably, interactions with nickel macromolecules, primarily through inhalation, have been demonstrated to promote lung cancer. Mechanisms of nickel-carcinogenesis range from oxidative stress, DNA damage, and hypoxia-inducible pathways to epigenetic mechanisms. Recently, non-coding RNAs have drawn increased attention in cancer mechanistic studies. Specifically, nickel has been found to disrupt expression and functions of micro-RNAs and long-non-coding RNAs, resulting in subsequent changes in target gene expression levels, some of which include key cancer genes such as p53, MDM2, c-myc, and AP-1. Non-coding RNAs are also involved in well-studied mechanisms of nickel-induced lung carcinogenesis, such as the hypoxia-inducible factor (HIF) pathway, oxidative stress, DNA damage and repair, DNA hypermethylation, and alterations in tumor suppressors and oncogenes. This review provides a summary of the currently known epigenetic mechanisms involved in nickel-induced lung carcinogenesis, with a particular focus on non-coding RNAs.

N-(((2-((2-Aminoethyl)amino)ethyl)amino)methyl)-4-sulfamoylbenzamide Impregnated Hydrous Zirconium Oxide as a Novel Adsorbent for Removal of Ni(II) from Aqueous Solutions: Optimization of Variables Using Central Composite Design

In this study, N-(((2-((2-aminoethyl)amino)ethyl)amino)methyl)-4-sulfamoylbenzamide was impregnated into the hydrous zirconium oxide matrix to yield N-(((2-((2-aminoethyl)amino)ethyl)amino)methyl)-4-sulfamoylbenzamide/hydrous zirconium oxide composite (AESB/HZO). The composite material was used to remove Ni(II) from aqueous environment. AESB/HZO was characterized using Fourier transform infrared, scanning electron microscopy with energy dispersive X-ray, and thermogravimetry-differential thermal analyses. An experimental design approach was utilized to model and optimize the variables of adsorption of Ni(II) onto the AESB/HZO composite. Four experimental parameters were selected as independent variables: contact time, pH, adsorbent dose, and initial Ni(II) concentration. A multivariable experimental design was used to establish quadratic model to describe the relationship between percent removal of Ni(II) and four independent variables. At the optimum conditions (contact time: 85 min, pH: 6, adsorbent dose: 10 mg/20 mL, and initial Ni(II) concentration: 20 mg L-1), high removal efficiency (99.35%) was achieved, which is reasonably well predicted by the quadratic model. The sorption of Ni(II) is dependent on pH and ionic strength at pH < 6.0. At low pH, -NH and -NH2 groups are protonated, whereas the -SO2- group is available for binding with Ni(II) and the sorption of Ni(II) is mainly governed by outer sphere surface complexation. In the pH range 6.0-7.5, -NH, -NH2, and -SO2- groups are available for binding with Ni(II) and the sorption is mainly governed by inner-sphere surface complexation. Adsorption isotherm data fitted well to the Langmuir model and the maximum adsorption capacity was found to be 96.03 mg g-1 at 303 K. The results of present investigation demonstrated that AESB/HZO has a good potential for Ni(II) removal from aqueous solution.

Electroplating for Decorative Applications: Recent Trends in Research and Development

Electroplating processes are widely employed in industrial environments for a large variety of metallic coatings, ranging from technological to decorative applications. Even if the galvanic electrodeposition is certainly a mature technology, new concepts, novel applications, environmental legislation and the new material requirements for next-generation devices make the scientific research in this field still very active. This review focuses mostly at the decorative and wearable applications, and aims to create a bridge between the past knowledge and the future direction that this process, i.e., electrodeposition, is taking. Both the theoretical fundamentals as well as some of the most widespread practical applications—limited to metallic and alloy coatings—are explored. As an integral part of the industrial process, we take a look at the main techniques thought which the quality control of deposits and surfaces is carried out. Finally, global industrial performance and research directions towards sustainable solutions are highlighted.

Physiochemical characteristics of aerosol particles collected from the Jokhang Temple indoors and the implication to human exposure

This paper presents a detailed study on the indoor air pollution in the Jokahng Temple at Tibet Plateau, and its implication to human health. The mean concentrations of PM_1.0 and PM_2.5 were 435.0 ± 309.5 and 483.0 ± 284.9 μg/m³, respectively. The PM_2.5 concentration exceeded the National Ambient Air Quality Standard (75 μg/m³) by 6.4 times. The size-segregated aerosols displayed a bimodal distribution. One peak was observed in the fine mode (0.4-2.1 μm) and the other peak appeared in the coarse mode (2.1-9.0 μm). The concentration of the total size-resolved PM was 794.3 ± 84.9 μg/m³. The mass fraction of coarse particles shared by 41.1%, apparently higher than that reported at low altitudes, probably due to incomplete combustion at Tibet Plateau with hypoxic atmospheric environment. The total concentration of polycyclic aromatic hydrocarbons (PAHs) was 331.2 ± 60.3 ng/m³, in which the concentration of benzo(a)pyrene (BaP) was 18.5 ± 4.3 ng/m³, over ten times higher than the maximum permissible risk value of 1 ng/m³ on account of carcinogenic potency of particulate PAHs through inhalation. PAHs exhibited a trimodal distribution, of which two peaks were observed in the fine mode and one peak in the coarse mode. With the aromatic rings increasing, the peak intensity increased in the fine mode. Na, Ca, Al, Mg and K dominated the elemental mass profiles, and metals displayed a bimodal distribution with a dominant peak in the coarse range. The total PAH deposition flux was 123.6 and 53.1 ng/h for adults and children, respectively. Coarse particles contributed most deposition flux in the head region, while fine particles contribute most deposition flux in the alveolar region. The increment lifetime cancer risk (ILCR) of PAHs ranaged at 10^-5-10^-4, indicating potential cancer risk to human health. The total deposition flux of metals was estimated at 1.4-13.2 ng/h. With the size increasing, deposition flux increased in the head region while decreased in the alveolar region. The highest ILCR of Cr and Ni were 4.9 × 10^-5 and 1.5 × 10^-6, respectively, exceeding the permissible risk of 10^-6. The hazard quotient (HQ) of Fe (10^-5-10^-4) and Zn (10^-6-10^-5) were much lower than the safe level of 1.0, and thus they were not considered as a health concern.

Prevalence of exposure of heavy metals and their impact on health consequences

Even in the current era of growing technology, the concentration of heavy metals present in drinking water is still not within the recommended limits as set by the regulatory authorities in different countries of the world. Drinking water contaminated with heavy metals namely; arsenic, cadmium, nickel, mercury, chromium, zinc, and lead is becoming a major health concern for public and health care professionals. Occupational exposure to heavy metals is known to occur by the utilization of these metals in various industrial processes and/or contents including color pigments and alloys. However, the predominant source resulting in measurable human exposure to heavy metals is the consumption of contaminated drinking water and the resulting health issues may include cardiovascular disorders, neuronal damage, renal injuries, and risk of cancer and diabetes. The general mechanism involved in heavy metal-induced toxicity is recognized to be the production of reactive oxygen species resulting oxidative damage and health related adverse effects. Thus utilization of heavy metal-contaminated water is resulting in high morbidity and mortality rates all over the world. Thereby, feeling the need to raise the concerns about contribution of different heavy metals in various health related issues, this article has discussed the global contamination of drinking water with heavy metals to assess the health hazards associated with consumption of heavy metal-contaminated water. A relationship between exposure limits and ultimate responses produced as well as the major organs affected have been reviewed. Acute and chronic poisoning symptoms and mechanisms responsible for such toxicities have also been discussed.

Nonrespiratory mortality and cancer incidence in a cohort of Canadian nickel workers

Mortality and cancer incidence were examined for an updated cohort of nonsinter nickel workers in Sudbury and Port Colborne, Ontario, Canada. Abstract results are provided for those with ≥ 15 years since first exposure. For circulatory disease mortality, significant elevations were observed overall in many Sudbury work areas and in Port Colborne staff. Underground miners, with first exposure before 1960, displayed significant elevations for pneumoconiosis, as well as silicosis and anthrasilicosis, likely due to crystalline silica. Significant elevations in colorectal cancer incidence were observed in Sudbury underground mining, mining maintenance, and maintenance work areas. Given a case-control study is not practical, the next cohort update should include more detailed occupational exposure assessment, including dust exposure, diesel engine emissions, solvents, various metals, silica, and sulphur dioxide.

Atmospheric size-resolved trace elements in a city affected by non-ferrous metal smelting: Indications of respiratory deposition and health risk

This study examines size-resolved heavy metal data for particles sampled near an urban site affected by non-ferrous metal smelting in China with a focus on how particle sizes impact regional respiratory deposition behavior. Particles with aerodynamic diameters between 0.43 and 9 μm were collected during winter haze episodes from December 2011 to January 2012. The results showed that concentrations of individual trace elements ranged from ∼10^-2-∼10⁴ ng/m³. Mass size distributions exhibit that Cu, Zn, As, Se, Ag, Cd, TI, and Pb have unimodal peak in fine particles range (<2.1 μm); Al, Ti, Fe, Sr, Cr, Co, Ni, Mo, and U have unimodal peak in coarse range (>2.1 μm), and Be, Na, Mg, Ca, Ba, Th, V, Mn, Sn, Sb, and K have bimodal profiles with a dominant peak in the fine range and a smaller peak in the coarse range. The total deposition fluxes of trace elements were estimated at 2.1 × 10^-2 - 4.1 × 10³ ng/h by the MPPD model, and the region with the highest contribution was the head region (42% ± 13%), followed by the tracheobronchial region (11% ± 3%) and pulmonary region (6% ± 1%). The daily intake of individual element for humans occurs via three main exposure pathways: ingestion (2.3 × 10^-4 mg/kg/day), dermal contact (2.3 × 10^-5 mg/kg/day), and inhalation (9.0 × 10^-6 mg/kg/day). A further health risk assessment revealed that the risk values for humans were all above the guidelines of the hazard quotient (1) and cancer risk (10^-6), indicating that there are potential non-cancer effects and cancer risks in this area.

Cancer incidence among copper smelting and nickel refining workers in Finland

BACKGROUND

Among workers employed at a nickel refinery in Harjavalta, Finland an increased risk of lung and sinus cancer has been demonstrated in two previous studies. The current study adds 16 more years of follow-up to these studies.

METHODS

A total of 1,115 persons exposed to nickel and 194 non-exposed workers in the Harjavalta nickel smelter and refinery were followed up for cancer from 1967 to 2011 through the Finnish Cancer Registry.

RESULTS

The total number of cancer cases in men was 251 (Standardized incidence ratio (SIR) 1.05) and in women 12 (SIR 1.22). In the most nickel-exposed work site (refinery), there were 14 lung cancers (SIR 2.01) and 3 sinonasal cancers (SIR 26.7, 95%).

CONCLUSIONS

It is likely that exposure to nickel compounds is the main reason for elevated nasal cancer risk among the nickel refinery employees and may also contribute to the excess risk of lung cancer. Am. J. Ind. Med. 60:87-95, 2017. © 2016 Wiley Periodicals, Inc.

Upregulation of SQSTM1/p62 contributes to nickel-induced malignant transformation of human bronchial epithelial cells

Chronic lung inflammation is accepted as being associated with the development of lung cancer caused by nickel exposure. Therefore, identifying the molecular mechanisms that lead to a nickel-induced sustained inflammatory microenvironment that causes transformation of human bronchial epithelial cells is of high significance. In the current studies, we identified SQSTM1/p62 as a novel nickel-upregulated protein that is important for nickel-induced inflammatory TNF expression, subsequently resulting in transformation of human bronchial epithelial cells. We found that nickel exposure induced SQSTM1 protein upregulation in human lung epithelial cells in vitro and in mouse lung tissues in vivo. The SQSTM1 upregulation was also observed in human lung squamous cell carcinoma. Further studies revealed that the knockdown of SQSTM1 expression dramatically inhibited transformation of human lung epithelial cells upon chronic nickel exposure, whereas ectopic expression of SQSTM1 promoted such transformation. Mechanistic studies showed that the SQSTM1 upregulation by nickel was the compromised result of upregulating SQSTM1 mRNA transcription and promoting SQSTM1 protein degradation. We demonstrated that nickel-initiated SQSTM1 protein degradation is mediated by macroautophagy/autophagy via an MTOR-ULK1-BECN1 axis, whereas RELA is important for SQSTM1 transcriptional upregulation following nickel exposure. Furthermore, SQSTM1 upregulation exhibited its promotion of nickel-induced cell transformation through exerting an impetus for nickel-induced inflammatory TNF mRNA stability. Consistently, the MTOR-ULK1-BECN1 autophagic cascade acted as an inhibitory effect on nickel-induced TNF expression and cell transformation. Collectively, our results demonstrate a novel SQSTM1 regulatory network that promotes a nickel-induced tumorigenic effect in human bronchial epithelial cells, which is negatively controlled by an autophagic cascade following nickel exposure.

Assessment of groundwater quality in the coastal area of Sindh province, Pakistan

Groundwater is a highly important resource, especially for human consumption and agricultural production. This study offers an assessment of groundwater quality in the coastal areas of Sindh province in Pakistan. Fifty-six samples of groundwater were taken at depths ranging from 30 to 50 m. Bacteriological and physico-chemical analyses were performed using the Standard Methods for the Examination of Water and Wastewater. These were supplemented with expert interviews and observations to identify the usage of water and potential sources of pollution. The quality of the groundwater was found to be unsuitable for human consumption, despite being used for this purpose. The concentrations of sulfate and phosphate were well within the tolerance limits. Most critical were the high levels of organic and fecal pollution followed by turbidity and salinity. Metal concentrations (As, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn) were also determined, and Ni and Pb strongly exceeded health standards. The study stresses the need for significant improvements of the irrigation, sanitation, and sewage infrastructure.

Estimation of Nickel in Different Smokeless Tobacco Products and Their Impact on Human Health of Oral Cancer Patients

It has been extensively investigated that the chewing of smokeless tobacco (SLT) products may enhance the inflammation of the oral cavity. The aim of the present study is to evaluate the relationship between nickel (Ni) exposure via different SLT products with oral cancer (different sites) incidence in the population of Sindh, Pakistan. The different brands of SLT products (mainpuri, gutkha, and moist snuff) commonly consumed by the studied population were analyzed for Ni contents. The biological samples of oral cancer patients and noncancerous control subjects of both genders, who have or have not consumed SLT products, were collected. The concentration of Ni in biological samples and SLT products were measured by electrothermal atomic absorption spectrophotometer after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked by using certified reference materials. The results of this study showed that the Ni level was significantly higher in scalp hair and blood samples of oral cancer patients compared to controls (P < 0.01). The study suggested that exposure of Ni as a result of chewing different SLT products may be synergistic with risk factors associated with oral cancer.

Comparison of essential and toxic elements in esophagus, lung, mouth and urinary bladder male cancer patients with related to controls

There is a compelling evidence in support of negative associations between essential trace and toxic elements in different types of cancer. The aim of the present study was to investigate the relationship between carcinogenic (As, Cd, Ni) and anti-carcinogenic (Se, Zn) trace elements in scalp hair samples of different male cancerous patients (esophagus, lung, mouth, and urinary bladder). For comparative purposes, the scalp hair samples of healthy males of the same age group (ranged 35-65 years) as controls were analyzed. Both controls and patients have the same socioeconomic status, localities, dietary habits, and smoking locally made cigarette. The scalp hair samples were oxidized by 65% nitric acid: 30% hydrogen peroxide (2:1) ratio in microwave oven followed by atomic absorption spectrometry. The validity and accuracy of the methodology were checked using certified reference material of human hair BCR 397. The mean concentrations of As, Cd, and Ni were found to be significantly higher in scalp hair samples of patients having different cancers as compared to the controls, while reverse results were obtained in the case of Se and Zn levels (p < 0.01). The study revealed that the carcinogenic processes are significantly affecting the trace elements burden and mutual interaction of essential trace and toxic elements in the cancerous patients.

Derivation of PM10 size-selected human equivalent concentrations of inhaled nickel based on cancer and non-cancer effects on the respiratory tract

Abstract Nickel (Ni) in ambient air is predominantly present in the form of oxides and sulfates, with the distribution of Ni mass between the fine (particle aerodynamic diameter < 2.5 µm; PM2.5) and coarser (2.5-10 µm) size-selected aerosol fractions of PM10 dependent on the aerosol's origin. When deriving a long-term health protective reference concentration for Ni in ambient air, the respiratory toxicity and carcinogenicity effects of the predominant Ni compounds in ambient air must be considered. Dosimetric adjustments to account for differences in aerosol particle size and respiratory tract deposition and/or clearance among rats, workers, and the general public were applied to experimentally- and epidemiologically-determined points of departure (PODs) such as no(low)-effect concentrations, for both cancer and non-cancer respiratory effects. This approach resulted in the derivation of threshold-based PM10 size-selected equivalent concentrations (modified PODs) of 0.5 µg Ni/m(3) based on workers' cancer effects and 9-11 µg Ni/m(3) based on rodent respiratory toxicity effects. Sources of uncertainty in exposure extrapolations are described. These are not reference concentrations; rather the derived PM10 size-selected modified PODs can be used as the starting point for the calculation of ambient air reference concentrations for Ni. The described approach is equally applicable to other particulates.

Nickel ion coupled counter complexation and decomplexation through a modified supported liquid membrane system

Complexation and decomplexation stoichiometry between nickel and D2EHPA in an SLM system are determined, confirmed by Job’s method and loading test.