Speciation of nickel in Canadian subbituminous and bituminous feed coals, and their ash by-products

The nickel species in the feed coals and ash by-products from seven Canadian power plants (including one with a fluidized bed combuster) burning local subbituminous and bituminous coals with sulfur contents ranging from 0.22 to 3.6% have been examined using nickel XANES spectroscopy. XANES spectroscopy of Ni in coal and coal derived ash is complicated by a poor signal : noise ratio due to fluorescence of the much more abundant iron in the coal. Nevertheless, it has proved possible to show that the Ni environment in coals varies from largely oxidic species to mixtures of Ni-containing oxide and sulfide species. The nickel in one oxidized coal appears to be present as nickel sulfate. Nickel in all bottom and fly ash samples examined appears also to be present largely in oxygen anion environments. With the exception of one fly ash sample, for which the Ni exhibited spectral features similar to those for Ni(2+) in spinel or oxide phases, the nickel in the bottom and fly ash samples appears to exist largely as Ni(2+) in environments similar to those reported for Ni in silicate glasses. The data obtained indicate that the presence of potentially carcinogenic nickel sulfides in ash by-products from combustion of these coals is unlikely.     

Correlation of urinary nickel excretion with observed 'total' and inhalable aerosol exposures of nickel refinery workers

An investigation of the relationship between observed nickel aerosol exposures and urinary nickel excretion was undertaken at a Scandinavian nickel refinery. The goal of the study was to assess the impact of nickel aerosol speciation, the use of particle size-selective sampling instrumentation and adjustment of urinary levels for creatinine excretion on the usefulness of urinary nickel excretion as a marker for exposure. Urinary nickel measurements and paired 'total' and inhalable aerosol exposure measurements were collected each day for one week from refinery workers in four process areas. The mean observed urinary nickel concentration was 12 micrograms L-1 (11 micrograms of Ni per g of creatinine). The strongest relationships between urinary excretion and aerosol exposure were found when urinary nickel levels were adjusted for creatinine excretion and when exposure to only soluble forms of nickel aerosol was considered. No significant difference was observed between measures of 'total' and inhalable aerosol in the ability to predict urinary excretion patterns. In the light of these results, it is recommended that consideration be given to the chemical species distribution of nickel aerosol in the use of urinary nickel measurements as a screening tool for cancer risk in occupationally-exposed populations.     

X-ray diffraction spectrometric analysis of nickel refinery aerosols,process materials and particulates isolated from worker lung tissues

Results are reported of X-ray diffraction analysis of extracts derived from lungs of two nickel refinery workers and of three stationary air samples collected inside a nickel refinery. Since environmental samples from the 1950s and 1960s do not exist, two archived production control samples from that period were also analyzed. Because nickel has been found in respiratory tissue of workers retired for more than twenty years, it was likely that the residual nickel compounds must be rather insoluble. Preliminary surveys showed that sulfur was not present in the lung tissue deposits and thus water-soluble and sulfidic nickel were therefore extracted from the ten process samples before the X-ray analysis. A common compound that was found in all 10 samples was trevorite. This is a spinel-type mineral, much like magnetite where the divalent iron is replaced by nickel. It may be formed when trivalent iron reacts with nickel at 1100 degrees C. It has magnetic properties and is very insoluble. Samples from the lungs were obtained by burning off the organic tissue at 630 degrees C. Due to a relatively high detection limit for the X-ray diffraction technique, we were initially not able to detect any mineral nickel compound. But when particles extracted with a magnet were analyzed, a very clear diffraction pattern of trevorite was identified. The main residue after the magnetic separation had a low concentration of nickel (4 microg g(-1)), which suggests that trevorite was the dominating, if not the only, nickel compound present. In addition, chemical analyses were performed on 13 tissue samples from one single lung; one from each main bronchus, two from each lobe, and an additional one from the lower right lobe. Statistical testing showed a highly significant correlation between the five elements determined: Ni, Co, Cu, Fe and Cr. This suggests that these metals are isomorphous and substitute for each other in the mineral structure. These results may indicate that the nickel left in the lungs some years after exposure is trevorite, and may be biologically inert. However, further speciation of nickel compounds in the lungs seems warranted, and trevorite should be tested for its potential toxic effects.     

Radiographic evidence of pulmonary fibrosis and possible etiologic factors at a nickel refinery in Norway

Animal studies have shown that nickel compounds may induce pulmonary fibrosis, but so far only limited documentation in humans has been available. Radiographs of 1046 workers in a nickel refinery in Norway were read blindly and independently by three NIOSH certified B-readers, according to the ILO standards. Pulmonary fibrosis (PF) was defined as a median reading of ILO score > or = 1/0 and following this criterion, 47 cases (4.5%) were identified. In logistic regression models, controlling for age and smoking, there was evidence of increased risk of PF with cumulative exposure to soluble nickel or sulfidic nickel (p = 0.04 for both). For metallic nickel a p-value of 0.07 was found. For soluble nickel there was a dose-response trend for 4 categories of cumulated exposure. In the group with the highest cumulative exposure to soluble nickel (low exposure as reference), the crude odds ratio for PF was 4.34 (95% CI 1.75-10.77). The risk adjusted for age, smoking, asbestos and sulfidic nickel was 2.24 (0.82-6.16), with a dose-response trend. The corresponding figures for sulfidic nickel were 5.06 (1.70-15.09, crude) and 2.04 (0.54-7.70, adjusted for age, smoking, asbestos and soluble nickel). However, the dose-response trend was less clear for sulfidic nickel. Controlling for estimated asbestos exposure at the refinery tended to increase the odds ratios of soluble and sulfidic nickel. This study indicates that in addition to age and smoking exposure to soluble and sulfidic nickel compounds are risk factors of PF in humans. Since the number of cases identified in this study is small and undetected confounders may have been present, further studies in other cohorts are appropriate.     

Speciation/fractionation of nickel in airborne particulate matter: improvements in the Zatka sequential leaching procedure

Modifications are reported to the sequential leaching analytical method for nickel speciation/fractionation specified by Zatka so that larger sample masses can be analyzed. Improvements have been made in the completeness of the sulfide/metallic separation during the peroxide-citrate leach step by use of a larger volume of leachant, a longer leach duration and an orbital shaker. Minimal extraction of metallic nickel in this prolonged sulfidic nickel extraction has been confirmed. An increase in the number of samples analyzed simultaneously using these modifications has resulted in substantial productivity improvements and concomitant lower costs. It is critical for practitioners of sequential leaching techniques to recognize potential limitations and to use professional judgment when interpreting results. For example, results obtained may not be biologically relevant in assessing health risks; the acts of sampling and storage may result in changes in fractionation with time; surface coatings/films may alter the ability of a leachant to react with the target compound; and leaching behaviours may be different for samples differing only in particle size distributions.     

Cigarette smoking and nickel exposure

The tobacco plant contains nickel and several other toxic metals, most probably absorbed from the soil, fertilizing products or from pesticides. It has been stated that nickel in a burning cigarette might form the volatile, gaseous compound, nickel tetracarbonyl, and thereby be introduced into the respiratory tract. Accordingly, the main objective of the present study was to find out if nickel content in inhaled smoke from ordinary cigarettes and nickel-contaminated cigarettes handmade by nickel process workers might be a supplementary source of nickel exposure to cigarette smoking process workers leading to additional risk of occupational respiratory cancer in these workers. Blood and urine samples from 318 randomly selected employees from Falconbridge Nickel Refinery in Kristiansand, Norway, allocated to 197 smokers and 121 non-smokers, were analysed for nickel content. Nickel quantities in tobacco from various cigarette brands, from nickel-contaminated cigarettes made by process workers or from cigarettes added known amounts of various nickel salts were analysed before being smoked. The cigarettes were smoked in a smoking machine device applying an electrostatic filter. Blood and urine, tobacco, ash and precipitates in the filter from the main stream smoke of the cigarettes were analysed for nickel quantities by atomic absorption spectrometry methods as previously described by the authors. The nickel concentrations in blood plasma and urine were quite similar among smokers and non-smokers, 6.2 and 48.1 microg L(-1) in smokers, and 6.4 and 50.5 microg L(-1) in non-smokers respectively. We recovered 1.1% or even less of nickel in the mainstream smoke after smoking the entire cigarettes without leaving any butt. Most of the tobacco nickel was recovered in the ash. We conclude that the inhaled nickel in the working atmosphere is probably the main source of the nickel exposure to the respiratory tract in these workers. It remains to be determined why cigarette smoking still seems to be a decisive cofactor in the development of respiratory tract cancer in nickel workers.     

Genotoxic evaluation of the insecticide endosulfan based on the induced GADD153-GFP reporter gene expression

Endosulfan is one of the few organochlorine insecticides still in use in China for protecting crops from a variety of insects. Endosulfan is toxic in fishes and rodents in the in vivo assays, but its genotoxicity in mammalian cells has not been well tested. In this work, a genotoxic testing system has been developed based on the induction of a HepG2/GADD153-GFP reporter gene expression in response to the DNA-damaging agents. Methyl methanesulfonate, a known carcinogenic and genotoxic agent, was used to test the effects of damage dose and post-treatment incubation time on GADD153-GFP expression. Subsequently, the system was applied to the genotoxicity evaluation of endosulfan. Endosulfan was able to cause the increase of GADD153-GFP expression at a sublethal dose (0.02?C20 mg/L). In particular, it induced a maximum green fluorescent protein expression at the tested concentration of 0.2 mg/L, with 4.07-fold inflorescence relative to untreated cells. The results suggest that endosulfan has the potential genotoxicity for HepG2 cell line by inducing DNA damage. The study also confirms that the induced GADD153-GFP expression system is an appropriate and sensitive method for the assessment of genotoxicity from a broad range of pesticides with the DNA-damaging potential.     

The heterogeneous composition of working place aerosols in a nickel refinery: a transmission and scanning electron microscope study

Size, morphology and chemical composition of individual aerosol particles collected in a nickel refinery were analyzed by scanning electron microscopy and energy-dispersive X-ray microanalysis (EDX). The phase composition was determined by selected area electron diffraction and EDX in a transmission electron microscope. Most particles are heterogeneous on a nanometer scale and consist of various phases. Nickel phases observed in the roasting and anode casting departments include metallic nickel, bunsenite (NiO), trevorite (Ni,Cu)Fe2O4, heazlewoodite Ni3S2, godlevskite (Ni,Cu)9S8, orthorhombic NiSO4 and an amorphous Ni,Cu.Al,Pb sulfate of variable composition. Additional phases encountered include corundum (Al2O3), murdochite (PbCu6O8), hexagonal Na2SO4, anhydrite (CaSO4), graphite (C) and amorphous carbon. The implications of the occurrence of the different Ni phases and their nanometer size for the study of adverse health effects are explored.     

Quantifying nickel in soils and plants in an ultramafic area in Philippines

In this study, concentrations of nickel (Ni) were quantified in the soils and plants in the agricultural areas of Salcedo watershed in Eastern Samar Island, Philippines. The quantity of total Ni in soils (TS-Ni) was significantly high with a mean of 1,409 mg kg^?1, while the soil available Ni (SA-Ni) was low with a mean of 8.66 mg kg^?1. As the levels of TS-Ni in the Salcedo watershed greatly exceeded the maximum allowable concentrations for agricultural soils, the site is not suitable for agricultural purposes. Despite significant TS-Ni levels, SA-Ni levels were very low due to tight binding between Ni and soil components. Consequently, all plants investigated did not meet the criterion for a Ni hyperaccumulator plant with low Ni contents (mean TP-Ni of 14.7 mg kg^?1). Comparison of Ni levels between food plants and its recommended daily intake (RDI) suggests that consumption of food-plants grown in the study area is unlikely to pose health risks. However, caution must be taken against combined consumption of food plants with high Ni levels or their prolonged consumption, as it can induce accumulation of Ni above RDI.     

Use of zeolite to neutralise nickel in a soil environment

Nickel is a heavy metal which is a stable soil pollutant which is difficult to remediate. An attempt to reduce its impact on the environment can be made by changing its solubility. The right level of hydrogen ions and the content of mineral and organic colloids are crucial in this regard. Therefore, methods to neutralise heavy metals in soil are sought. There are no reports in the literature on the possibility of using minerals in the detoxication of a soil environment contaminated with metals. It is important to fill the gap in research on the effect of zeolites on the microbiological, biochemical and physicochemical properties of soils under pressure from heavy metals. Therefore, a pot experiment was conducted on two soils which examined the effect of various levels of contamination of soil with nickel on the activity of soil enzymes, physical and chemical properties and growth and development of plants. An alleviating effect of zeolite Bio.Zeo.S.01 on the negative impact of nickel on the soil and a plant (oats) was examined. The enzyme activity and the oat yield were found to be significantly and negatively affected by an excess of nickel in the soil, regardless of the soil type. The metal was accumulated more in the oat roots than in the above-ground parts. An addition of zeolite decreased the level of accumulation of nickel in oats grown only on sandy-silty loam. Zeolite Bio.Zeo.S.01 used in the study only slightly alleviated the negative effect of nickel on the biochemical properties of soil. Therefore, its usability in the remediation of soil contaminated with nickel is small.     

Effects of soil copper and nickel on survival and growth of Scots pine

The contribution of soil Cu and Ni pollution to the poor vitality and growth rate of Scots pine growing in the vicinity of a Cu-Ni smelter was investigated in two manipulation experiments. In the first manipulation, Cu-Ni smelter-polluted soil cores were transported from a smelter-pollution gradient to unpolluted greenhouse conditions. A 4-year-old pine seedling was planted in each core and cultivated for a 17-month period. In the second manipulation, pine seedlings from the same lot were cultivated for the same 17-month period in a quartz sand medium containing increasing doses of copper sulfate, nickel sulfate, and a combination of both. The variation in the biomass growth of the seedlings grown in the smelter-polluted soil cores was very similar to that of mature pine stands growing along the same smelter-pollution gradient in the field. In addition, the rate of Cu and Ni exposure explained a high proportion of the biomass growth variation, and had an effect on the Ca, K, and Mg status of the seedlings. According to the lethal threshold values determined on the basis of the metal sulfate exposure experiments, both the Cu and Ni content of the 0.5 km smelter-polluted soil cores were high enough to cause the death of most of the seedlings. The presence of Cu seemed to increase Ni toxicity.     

江蓠对水体重金属铅镍的蓄积及生物修复研究

以活体细基江篱繁枝变型(Gracilariatunuistipitata var)作为研究材料,以Pb、Ni重金属离子为污染因子,通过室内静态模拟实验,综合利用等离子发射光谱仪,超速离心机.差速离心机等实验手段研究在单一离子污染胁迫下,江蓠对Pb、Ni重金属离子的短期去除效果,各重金属离子在其体内蓄积效应,江蓠质外体、...     

Multi-component assessment of worker exposures in a copper refinery. Part 2. Biological exposure indices for copper, nickel and cobalt

Urinary copper (Cu), nickel (Ni) and cobalt (Co) concentrations were determined for 127 Cu refinery workers (40 females, 87 males), with values of the 95% upper confidence interval of the geometric mean in nmol per mmol creatinine of 89 (Ni), 42 (Cu) and 3.4 (Co) for electrorefinery workers. In the pyrometallurgical departments, the corresponding concentrations were 37 (Ni), 99 (Cu) and 11 (Co). Female workers had higher Co urinary concentrations than males (p< or = 0.05) while no gender difference was observed for Cu and Ni. Inter-elemental correlations were moderate to weak. Based on the inhalable aerosol levels reported previously for the same workers, the observed urinary Cu concentrations were considerably lower than expected, relative to Co and Ni. This is interpreted in terms of the current understanding of Cu homeostasis.     

Prolonged toxicity characteristic leaching procedure for nickel and copper aluminates

The toxicity characteristic leaching procedure (TCLP) is a regulatory testing method widely employed to evaluate the environmental friendliness of waste materials. TCLP analysis provides a fast, easy and economical way to determine the mobility of waste pollutants under simulated landfill conditions. Recent studies on metal stabilization have reported the potential for nickel and copper aluminates to form in thermal treatment conditions, and suggested a more reliable method of stabilizing hazardous metals, particularly when products are to be reused. There is thus an urgent need for a convenient and effective method of quantifying metal leachability and identifying the metal leaching behavior of sparingly soluble materials. In this study, standard TCLP analysis was modified into a prolonged leaching experiment to investigate the leaching behavior of nickel and copper oxides (NiO and CuO) and their aluminates (NiAl(2)O(4), CuAl(2)O(4) and CuAlO(2)). The results demonstrate the difficulty of differentiating the leachability of highly insoluble phases, such as NiO and NiAl(2)O(4), using the standard TCLP. The prolonged TCLP method, however, confirmed NiAl(2)O(4) to have a lower degree of intrinsic leachability than NiO and that it could be expected to undergo congruent dissolution under landfill conditions. For the more soluble copper system, the aluminates were still found to possess a much lower degree of leachability, and their leaching behavior to follow an incongruent dissolution pattern. The results of this study prove prolonged TCLP analysis to be a convenient and effective way to evaluate the environmental friendliness of metal waste and to identify the leaching behavior of waste materials.     

The hygroscopic behaviour of individual aerosol particles in nickel refineries as investigated by environmental scanning electron microscopy

The hygroscopic properties of individual aerosol particles (1-35 microm equivalent projected area diameter) from the Roasting, Anode Casting and Electrorefining Departments of two Ni refineries were studied by environmental scanning electron microscopy (ESEM) and energy-dispersive X-ray microanalysis (EDX) at a relative humidity of 96-98% (at a temperature of 5 degrees C). In the Roasting and Anode Casting Departments, most particles (60-85% by number) showed no visible change in size or surface morphology when exposed to high relative humidity. Approximately 15-30% of the particles developed a thin water film (growth factors between 1.006 and 1.06) indicating the presence of thin surface coatings of sulfates. About 10% of the particles in the Roasting Department formed droplets (growth factors between 1.1 and 2.6) which always contained a large portion of insoluble material. In the Electrorefining Department, most particles (approximately 60%) were residues from the electrolysis bath solution. At a relative humidity of 96-98% these particles formed a solution which contained only small insoluble inclusions. About 30% of the particles in the Electrorefining Department developed thin water films. As only a small fraction of the particles increased substantially in size when exposed to high relative humidity, the deposition pattern of the total aerosol mass fraction will not be changed substantially by hygroscopic growth. The frequent occurrence of thin surface coatings of soluble material on insoluble Ni compounds has to be considered for health assessment purposes.     

Analysis of cadmium, nickel, and lead in commercial moist and dry snuff used in Pakistan

The extent to which smokeless tobacco endangers human health is an ongoing subject of debate. In this study, concentrations of toxic metals, cadmium (Cd), lead (Pb), and nickel (Ni), were measured in different snuff products (dry brown and black and moist green and brown), available and consumed in Pakistan. Concentrations of Cd, Pb, and Ni were determined in 23 samples of various brands of snuff by electrothermal atomic absorption spectrometry, after microwave-assisted acid digestion. The reliability of methodology was assured by analyzing certified reference material. The resulted data of toxic metals in different snuff products are comparable to the existing information with limited exceptions. It was estimated that 10 g intake of different types of snuff could contribute 14–68, 17–47, and 20–73 % of the provisional maximum tolerable daily intake for Cd, Ni, and Pb, respectively.     

Establishing normal values for nickel in human lung disease

People working in the nickel refining industry are known to have a higher concentration of nickel in lung tissue than the general population. To be able to evaluate a potential nickel exposure from other sources, e.g., welding, it is important to have sufficient data on what is normal for a local population. Several local factors such as the content of nickel in air and soil can have a significant impact on this so-called normal value. As almost all surgical equipment contains nickel, the sampling process can in itself be a source of contamination. The scope of this work was to investigate if there was any measurable contamination from the sampling instruments routinely used in hospitals, and if the presence of a nickel refinery had any effect on the nickel content in the lungs of the general population. Autopsy lung tissue samples were collected in situ from 50 people who had lived in the county of Vest Agder in Norway. Two samples were collected from each person; one with a regular scalpel (Swann-Norton) and forceps, and one with a titanium knife and plastic forceps. None of the persons had any known connection to the nickel refinery. The samples were collected at random and no special attention was given to age, sex and place of residence. The autopsies were performed according to Norwegian law and in understanding with the next of kin. The arithmetic mean value +/- s of nickel was 0.64 +/- 0.56 microgram g-1 and 0.29 +/- 0.20 microgram g-1 dry weight, respectively, for samples collected with a regular scalpel and a titanium knife (P < 0.0001). For people who lived 8 km and closer to the refinery by the time of death, the nickel content was 0.41 +/- 0.19 microgram g-1 and for those who had lived between 8 and 70 km away from the refinery it was 0.18 +/- 0.13 microgram g-1 (P < 0.015). No statistical difference was established between results for males and females. Previous investigations have shown that the nickel content in lung tissue varies in the so-called normal population. This work has shown that factors such as sampling equipment and place of residence have an impact on the results. It thus demonstrates that reliable background values can presumably only be obtained by collecting samples from individuals not exposed to known environmental nickel sources and to use nickel-free instruments in the sampling process.     

城市河流重金属元素对降雨径流的动态响应

以海口市美舍河市区河段为研究对象,于2020年雨季分别采集降雨径流以及降雨径流汇入后的河流瞬时水样,测定并分析主要重金属元素的浓度及其变化规律,探讨其对降雨径流的动态响应。研究结果表明：降雨径流对河流可溶态污染元素质量浓度的贡献不突出,对可溶态锌（Zn）、砷（As）、镉（Cd）、硒（Se）具有一定稀释作用,排水口下游 3 m处是可溶态铬(Cr）、锰（Mn）、钴（Co）对降雨径流响应最显著区域;降雨径流对各悬浮态元素质量浓度贡献较大,排水口下游7 m处是绝大多数悬浮态元素对降〖JP〗雨径流响应最显著区域;Mn、Zn、Cr、镍（Ni）、As、Co、Cd 7种元素的总质量浓度对降雨径流的动态响应表现为先上升后下降。其中,排水口下游3 m处是Cr、As总质量浓度对降雨径流响应最显著区段,排水口下游7 m处是Mn、Co、Ni、Zn及Cd总质量浓度对降雨径流响应最显著区段。降雨径流对河流主要污染元素年输入总量估算结果表明,海口市建成区降雨径流向美舍河等受纳水体直接年输入量最大的是Mn和Zn,其次是Cr、As、Ni,Se与Cd的年输入量最小。     

Studies on the Uptake of Heavy Metals by Various Plant Species on Chromite Minespoils in Sub-tropical Regions of India

The presence of heavy metals (Cr, Ni and Fe) in soil and accumulated by herbs, shrubs and trees regenerated naturally on the minewaste-dumps of Sukinda chromite mines (TISCO sector) were investigated. There was significant correlationship between Cr and Fe in the soil where a tree species (Catunaregam spinosa) occurred. Guazuma ulmifolia and Diospyros montana also did show significant correlation between leaf, stem and soil for Cr, Ni and Fe. Among the shrubs (Calotropis gigantea, Chromolaena odorata, Phyllanthus reticulatus and Woodfordia fruticosa) significant and positive correlations were obtained for Cr and Ni in soil and iron and nickel in leaf and chromium and nickel in stem. Among the annual herbs, whole plant of tephrosia purpurea and Borrevia articularis showed significant and positive correlation with chromium and nickel with the maximum correlation coefficient value. It was concluded that the above information would be useful in revegetation programmes in subtropical regions having seasonal rainfall.