Nickel species: analysis and toxic effects

This review gives an overview on the analysis of inorganic nickel species and their toxic effects. Based on the analytical procedure applied inorganic nickel species are usually classified in soluble, sulfidic, metallic and oxidic nickel fractions. Only few works were attempting a chemical characterization of the different nickel compounds in each fraction. This general classification in four nickel species groups is widely used in toxicological studies dealing with nickel particulate matter in workplace air. Compared to the general population, occupationally exposed people have a higher risk of respiratory tract cancer due to inhalation of nickel at their workplace in the nickel-producing or using industries. High cancer risk is related to less soluble oxidic and especially sulfidic nickel species in refinery dust. In contrast, within the general population the most harmful health effect related to nickel exposure is allergic contact dermatitis due to prolonged skin contact with nickel. Absorption processes of nickel species and molecular mechanisms of nickel toxicity are briefly outlined.     

Plant uptake and phytotoxicity of boron in Australian fly ashes

Summary French bean (Phaseolus vulgaris cv. Redland Pioneer) and Rhodes grass (Chloris gayana cv. Pioneer) were grown in glasshouse experiments to examine the potential for phytotoxicity of B in a range of Australian fly ashes. In each experiment, the ashes used were either untreated, leached or adjusted to pH 6.5 and subsequently leached.In the first eperiment, the yield and B status of plants grown on five fly ashes mixed (5 and 10% by weight) with an acid-washed sand were measured and, with the exception of one ash, yield differences among ash sources and among ash treatments were attributed to differences in the degree of B toxicity. In a subsequent experiment, a fly ash with properties representative of most Australian ashes was mixed (0, 15, 30, 70 and 100% by weight) with a sandy loam, and the yield and mineral composition of plants grown on these mixtures determined. Although the available water capacity of the soil was substantially increased by fly ash addition, incorporating large proportions of untreated fly ash resulted in poor plant growth primarily due to B toxicity. In both experiments, leaching the ash reduced the potential for B toxicity, whereas adjustment of the pH to 6.5 and subsequent leaching of the fly ash resulted in plants with normal levels of B.There were marked differences in both the tissue levels of B and the extent of B toxicity symptoms between the two species. Rhodes grass appeared to be able to tolerate higher B contents in the growing medium by taking up much less of the element than French bean. The results indicate that phytotoxicity of B would be a major problem in establishing vegetation on ash dams and in the agronomic utilization of unweathered fly ashes in Australia.     

Suitability of Brahmi (Bacopa monnieri L.) cultivation on fly ash-amended soil for better growth and oil content

Abstract

Sustainable application of fly ash and its management in agriculture is a major challenge nowadays. A pot culture experiment was conducted to find out the most suitable level of fly ash application for soil amendments that can improve the plant growth and productivity of Brahmi (Bacopa monnieri L.). After growing seedlings of B. monnieri under different levels of fly ash for 90?days, a significant increase in plant biomass, essential oil content and tolerance index (more than 100%) was observed under 25% of fly ash amended soil in comparison to garden soil and higher fly ash treatments. Leaf chlorophyll content and photosynthetic parameters were remained unchanged under 25% of fly ash as compared to seedlings grown on garden soil. However, these parameters were significantly declined under higher concentrations of fly ash treatments. Higher levels of fly ash caused oxidative damage and the induction of some antioxidative enzymes activities in B. monnieri indicates its capability to endure oxidative stress tolerance. Overall, our study showed that 25% of fly ash can be used as soil amendment for cultivation of B. monnieri L. leading to enhance plant biomass and essential oil production.     

Characteristics of boron accumulation by fly ash application in paddy soil

Fly ash has a high content of plant available silicate which is strongly needed for rice cultivation in Korea. One concern for plants grown on soils amended with fly ash is boron (B) toxicity because most of the fresh fly ash contains considerable B. This study was conducted in paddy soil to determine B uptake by rice and characteristics of B accumulation in soil after fly ash application (0, 40, 80, and 120 Mg fly ash ha⁻¹). In all fly ash treatments, B content in rice leaves and available B in soil at all growing stage were higher than those of control, but were not exceeded a toxicity levels. Boron occluded in amorphous Fe and Al oxides comprised ca. 20–39% of total B and was not affected by fly ash application. Most of the B was accumulated by fly ash application as a residual B which is plant-unavailable form, comprised >60% of the total B in soil. Thus, fly ash can be a good soil amendment for rice production without B toxicity.     

Effect of coal ash on growth and metal uptake by some selected ectomycorrhizal fungi in vitro

Six isolates of ectomycorrhizal fungi namely, Laccaria fraterna (EM-1083), Pisolithus tinctorius (EM-1081), Pisolithus tinctorius (EM-1290), Pisolithus tinctorius (EM-1293), Scleroderma verucosum (EM-1283), and Scleroderma cepa (EM-1233), were grown on three variants of coal ash, namely electrostatically precipitated (ESP) ash, pond ash, and bottom ash moistened with Modified Melin-Norkans (MMN) medium in vitro The colony diameter reflected the growth of the isolates on the coal ash. Metal accumulation in the mycelia was assayed by atomic absorption spectrophotometry. Six metals, namely aluminum, cadmium, chromium, iron, lead, and nickel, were selected on the basis of their abundance in coal ash and toxicity potential for the present work. Growth of vegetative mycelium on fly ash variants and metal accumulation data indicated that Pisolithus tinctorius (EM-1290) was the most tolerant among the isolates tested for most of the metals. Since this isolate is known to be mycorrhizal with Eucalyptus, it could be used for the reclamation of coal ash over burdened sites.     

Impact of Contaminants From Oil Shale Processing on Forest Ecosystems

Oil shale mining and processing in northeast Estonia have brought about several ecological problems. The mined oil shale is used as fuel in power stations and in processing plants producing crude oil and about 40 manufactured articles. Pollutants emitted from oil shale processing and chemical plants include SO₂, CO, NO _x , oil shale fly ash, and organic compounds in which aromatic and aliphatic hydrocarbons, phenols, formaldehyde, etc., are represented. Pollution has caused changes in the condition of the forest ecosystem and the chemical character of soil and ground water. The condition of coniferous forest sites was investigated in 1995–1998. Because of the high concentration of alkaline fly ash in the air, the pH of rain water is somewhat elevated (pH = 7.0–7.1) and exceeds the level regarded as normal for rain water. The analysis of the soil samples showed that the concentrations of Ca, Mg and K, which dominate in the solid fraction of the pollutant mixture, are high, being respectively 18, 14, and 4 times as high as the control. The increases in the concentrations of K, Mg, Cu, Pb, and Ni in stemwood reflect increases in the regional oil shale fly ash deposition. Conifers influenced by high levels of air pollution emitted from the oil shale industry are characterized by retarded growth of needles and shoots and radial growth as a result of disturbances in their mineral nutrition and imbalance in their mineral composition.     

Contact Toxicity and Repellency of the Essential Oil from Mentha haplocalyx Briq. against Lasioderma serricorne

The chemical composition of the essential oil obtained by hydrodistillation from the aerial parts of Mentha haplocalyx was investigated by GC‐FID and GC/MS analyses. In sum, 23 components, representing 92.88% of the total oil composition, were identified, and the main compounds were found to be menthol (59.71%), menthyl acetate (7.83%), limonene (6.98%), and menthone (4.44%). By bioassay‐guided fractionation (contact toxicity), three compounds were obtained from the essential oil and identified as menthol, menthyl acetate, and limonene. The essential oil and the three isolated compounds exhibited potent contact toxicity against Lasioderma serricorne adults, with LD₅₀ values of 16.5, 7.91, 5.96, and 13.7 μg/adult, respectively. Moreover, the oil and its isolated compounds also exhibited strong repellency against L. serricorne adults. At the lower concentrations tested and at 2 h after exposure, menthol showed even significantly stronger repellency than the positive control DEET. The study revealed that the bioactivity properties of the essential oil can be attributed to the synergistic effects of its diverse major and minor components, which indicates that the M. haplocalyx oil and its isolated compounds have potential for the development as natural insecticides and/or repellents to control insects in stored grains and traditional Chinese medicinal materials.     

Metallic nickel nano- and fine particles induce JB6 cell apoptosis through a caspase-8/AIF mediated cytochrome c-independent pathway

Background  

Carcinogenicity of nickel compounds has been well documented. However, the carcinogenic effect of metallic nickel is still unclear. The present study investigates metallic nickel nano- and fine particle-induced apoptosis and the signal pathways involved in this process in JB6 cells. The data obtained from this study will be of benefit for elucidating the pathological and carcinogenic potential of metallic nickel particles.     

Chemical Composition and Cytotoxic Evaluation of the Essential Oil of Phyllogonium viride (Phyllogoniaceae,Bryophyta)

The present study aimed to determine the chemical composition and biological activity of the essential oil obtained from Phyllogonium viride Brid. (Phyllogoniaceae, Bryophyta), whose samples were collected in southern Brazil. For the first time, the cytotoxic activity of the essential oil of P. viride in breast and colorectal tumor cells (MCF-7 and HCT-116) was evaluated, as well as the cytotoxic potential of this oil in non-tumoral cells of human immortalized keratinocytes (HaCaT) via MTT assay. The compounds majorly found in P. viride essential oil were β-bazzanene (20.30 %), β-caryophyllene (17.06 %), β-chamigrene (14.02), and germacrene B (11.72 %). Treatment with P. viride essential oil in the different tested cell lines did not induce any toxicity in most of the tested concentrations. These data contribute to generating new scientific information about this understudied plant species. Furthermore, the chemical characterization of the compounds present in the essential oil of P. viride can lead to greater elucidation of its biotechnological potential.     

Effect of two biodegradable chelates on metals uptake,translocation and biochemical changes of Lantana Camara growing in fly ash amended soil

The present work had two purposes firstly to evaluate the potential of Lantana Camara for phytoextraction of heavy metals from fly ash amended soil and to assess the suitability of a proper biodegradable chelating agent for chelate assisted phytoextraction. Plants were grown in manure mixed soil amended with various concentration of fly ash. Two biodegradable chelating agents were added (EDDS and MGDA) in the same dose separately before maturation stage. Sampling was done at different growing stages. The plant took up metal in different plant parts in the following order: for Cu, and Zn leaf >root >stem, for Cr and Mn leaf>stem >root, for Ni root >leaf>stem and for Pb root≈leaf>stem respectively. For Cu, Zn, Cr and Mn Lantana camara acted as phytoextractor. Translocation factor and bioaccumulation coefficient was>1 signifying enrichment and translocation of metals in the plant. Morphological studies showed no toxicity symptom in the plant. Among biochemical parameters protein and nitrate reductase activity decreased, whereas, chlorophyll and peroxidise activity increased with the growth stages. Finally, it was evident from the results that Lantana Camara can be used as efficient phytoextractor of metals, with proper harvesting cycle and both chelate were proved as effective chelators for phytoextraction of metals.     

Natural revegetation of coal fly ash in a highly saline disposal lagoon in Hong Kong

Question: What is the relationship of the naturally colonizing vegetation and substrate characteristics in fly ash lagoons? Location: West lagoon, Deep Bay, a 13‐ha coastal lagoon in Hong Kong in subtropical Southeast Asia. Methods: Vegetation establishment was examined in a coal fly ash lagoon two years after its abandonment to investigate the distribution of vegetation in relationship to the chemical properties of the fly ash in the lagoon. A greenhouse experiment assessed the limits imposed on plant growth in fly ash. Results: The fly ash was saline, slightly alkaline and very poor in organic matter and nitrogen. Ash from bare and vegetated areas differed significantly in their salinity and extractable concentrations of inorganic nitrogen and various metals. Bare ash had a significantly higher conductivity and extractable sodium, aluminum, manganese, potassium, and lead. In total 11 plant species that belonged to seven families were found growing on the fly ash; all species except the shrub Tamarix chinensis were herbaceous. Using discriminant analysis, the most important factors in distinguishing bare and vegetated ashes were conductivity and sodium. Cluster analysis of bare samples gave two distinct groups, one from the periphery of the lagoon, which had lower sodium, conductivity, organic carbon, potassium and copper, and the other from a second group that contained ashes from the central region of the lagoon. Results of the greenhouse experiment showed that the inhibition of plant growth was significantly correlated with the presence of soluble toxic elements in ash. Conclusion: Toxicity and salinity seem to be the major limiting factors to plant establishment in fly ash, and these factors must be ameliorated for the successful reclamation of these fly ash lagoons.     

Bioleaching of cobalt from smelter wastes byThiobacillus ferrooxidans

Summary The bioleaching of cobalt from domestic, industrial smelter wastes was studied.Thiobacillus ferrooxidans solubilized Co from sulfidic dross furnace mattes. At pulp densities of 4% (w/v) up to 600 mg of Co per liter of leaching solution was released from nickel matte, corresponding to removal of about two-thirds of the original amount of Co in the matte. Bioleaching methods may be useful as a component of a process for solubilization and recovery of Co from sulfidic smelter mattes.     

Efficacy and safety of catnip (Nepeta cataria) as a novel filth fly repellent*

Catnip (Nepeta cataria) is known for its pseudo‐narcotic effects on cats. Recently, it has been reported as an effective mosquito repellent against several Aedes and Culex species, both topically and spatially. Our laboratory bioassays showed that catnip essential oil (at a dosage of 20 mg) resulted in average repellency rates of 96% against stable flies, Stomoxys calcitrans (L.) and 79% against houseflies, Musca domestica (L.), respectively. This finding suggested that the application of repellent could be used as part of filth fly management. Further evaluations of catnip oil toxicity were conducted to provide a broad‐spectrum safety profile of catnip oil use as a potential biting and nuisance insect repellent in urban settings. Acute oral, dermal, inhalation, primary dermal and eye irritation toxicity tests were performed. The acute oral LD₅₀ of catnip oil was found to be 3160 mg/kg body weight (BW) and 2710 mg/kg BW in female and male rats, respectively. The acute dermal LD₅₀ was > 5000 mg/kg BW. The acute inhalation LD₅₀ was observed to be > 10 000 mg/m³. Primary skin irritation tested on New Zealand white rabbits showed that catnip oil is a moderate irritant. Catnip oil was classified as practically non‐irritating to the eye. In comparison with other U.S. Environmental Protection Agency‐approved mosquito repellents (DEET, picaridin and p‐menthane‐3,8‐diol), catnip oil can be considered as a relatively safe repellent, which may cause minor skin irritation.     

Effects of Eclipta alba on the morphometrics of root-knot nematode,Meloidogyne incognita as influenced by fly ash amended soil

An experiment in a complete randomised design was conducted with the aim of investigating the impact of graded quantities (10, 20, 30, 40 and 50%) of fly ash on the morphometrics of root-knot nematode, Meloidogyne incognita (2000 J₂/pot) in Eclipta alba. The application of fly ash brought about deleterious effects on the development of the nematode which were reflected on dimensions of the mature females in all the fly ash concentrations over the inoculated control (IC). Significant reductions in length and width of body, neck, stylet and median bulbs of the mature females were recorded at higher (40 and 50%) fly ash levels, when compared with inoculated control (IC). The severity of root-knot disease was found to be decreased with increasing fly ash concentrations.     

Nitrogen nutrition inAtriplex hastata L.

Summary The investigation was carried out in order to ascertain whyAtriplex hastata, previously recorded as a nitrophilous plant, can colonise fly ash which has a low nitrogen content.Sinapis arvensis, a weed which does not grow on fly ash, was selected as a control plant. Solution-culture experiments showed that the two species differed in their responses to high and low levels of nitrogen, the growth rate ofS. arvensis being much more severely affected by low levels of 0 to 50 ppm.A. hastata was found to make very efficient use of its nitrogen supply. Both species grew better with nitrate than with ammonium nitrogen. InA. hastata, uptake of nitrogen was not influenced by pH when only nitrate was present. Where both nitrate and ammonium were available, nitrate was absorbed preferentially at low pH and ammonium at high pH. Some properties of fly ash which render it a suitable medium for growth ofA. hastata are discussed.     

Hydrocarbon-Degrading Bacteria Exhibit a Species-Specific Response to Dispersed Oil while Moderating Ecotoxicity

The Deepwater Horizon blowout in April 2010 represented the largest accidental marine oil spill and the largest release of chemical dispersants into the environment to date. While dispersant application may provide numerous benefits to oil spill response efforts, the impacts of dispersants and potential synergistic effects with crude oil on individual hydrocarbon-degrading bacteria are poorly understood. In this study, two environmentally relevant species of hydrocarbon-degrading bacteria were utilized to quantify the response to Macondo crude oil and Corexit 9500A-dispersed oil in terms of bacterial growth and oil degradation potential. In addition, specific hydrocarbon compounds were quantified in the dissolved phase of the medium and linked to ecotoxicity using a U.S. Environmental Protection Agency (EPA)-approved rotifer assay. Bacterial treatment significantly and drastically reduced the toxicity associated with dispersed oil (increasing the 50% lethal concentration [LC₅₀] by 215%). The growth and crude oil degradation potential of Acinetobacter were inhibited by Corexit by 34% and 40%, respectively; conversely, Corexit significantly enhanced the growth of Alcanivorax by 10% relative to that in undispersed oil. Furthermore, both bacterial strains were shown to grow with Corexit as the sole carbon and energy source. Hydrocarbon-degrading bacterial species demonstrate a unique response to dispersed oil compared to their response to crude oil, with potentially opposing effects on toxicity. While some species have the potential to enhance the toxicity of crude oil by producing biosurfactants, the same bacteria may reduce the toxicity associated with dispersed oil through degradation or sequestration.     

AM真菌在煤矿废弃物中生态适应性的初步研究

以粉煤灰、草炭、蛭石、河沙为培养基质,分别对4种不同AM真菌:Glomus mosseae,G.diaphanum,G.intraradices和G.versiforme的生态适应性进行研究。结果表明,菌根的侵染率、孢子密度和菌丝长度分别与菌根真菌种类、培养基质状况及寄主植物种类有关。4种基质的扩繁效果顺序为:河沙>粉煤灰>草炭>蛭石。G.mosseae和G.diaphanum在基质中的产孢量和菌丝长度优于G.intraradices和G.versiforme,可作为优势菌株。4种菌根真菌在粉煤灰中对寄主的侵染率均达到60%以上,粉煤灰作为菌根真菌培养基质具有更大潜力和实际应用价值。     

Impact of fly ash content and fly ash transportation distance on embodied greenhouse gas emissions and water consumption in concrete

Background, aim and scope  

Fly ash, a by-product of coal-fired power stations, is substituted for Portland cement to improve the properties of concrete and reduce the embodied greenhouse gas (GHG) emissions. Much of the world’s fly ash is currently disposed of as a waste product. While replacing some Portland cement with fly ash can reduce production costs and the embodied emissions of concrete, the relationship between fly ash content and embodied GHG emissions in concrete has not been quantified. The impact of fly ash content on embodied water is also unknown. Furthermore, it is not known whether a global trade in fly ash for use in concrete is feasible from a carbon balance perspective, or if transport over long distances would eliminate any CO₂ savings. This paper aims to quantify GHG emissions and water embodied in concrete (f′_c = 32 MPa) as a function of fly ash content and to determine the critical fly ash transportation distance, beyond which use of fly ash in concrete increases embodied GHG emissions.