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Characterization of indoor diesel exhaust emissions from the parking garage of a school Texte intégral
2017
Debia, Maximilien | Trachy-Bourget, Marie-Claude | Beaudry, Charles | Neesham-Grenon, Eve | Perron, Stéphane | Lapointe, Caroline
Diesel exhaust (DE) emissions from a parking garage located in the basement of a school were characterized during spring and winter using direct reading devices and integrated sampling methods. Concentrations of CO and NO₂ were evaluated using electrochemical sensors and passive colorimetric tubes, respectively. Elemental and total carbon concentrations were measured using the NIOSH 5040 method. Particle number concentrations (PNCs), respirable particulate matter (PMᵣₑₛₚ) mass concentrations, and size distributions were evaluated using direct reading devices. Indoor concentrations of elemental carbon, PNC, CO, and NO₂ showed significant seasonal variation; concentrations were much higher during winter (p < 0.01). Concentrations of the PMᵣₑₛₚ and total carbon did not show significant seasonal variation. Pearson correlation coefficients were 0.9 (p < 0.01) and 0.94 (p < 0.01) between the parking garage and ground floor average daily PNCs, and between the parking garage and first floor average daily PNCs, respectively. Since DE is the main identified source of fine and ultrafine particles in the school, these results suggest that DE emissions migrate from the parking garage into the school. Our results highlight the relevance of direct reading instruments in identifying migration of contaminants and suggest that monitoring PNC is a more specific way of assessing exposure to DE than monitoring the common PMᵣₑₛₚ fraction.
Afficher plus [+] Moins [-]Physicochemical properties, in vitro cytotoxic and genotoxic effects of PM1.0 and PM2.5 from Shanghai, China Texte intégral
2017
Zou, Yajuan | Wu, Yizhao | Wang, Yali | Li, Yinsheng | Jin, Chengyu
Exposure to ambient particulate matter (PM) links with a variety of respiratory diseases. However, compared with coarse particles (PM₁₀) and fine particles (PM₂.₅), submicrometer particles (PM₁.₀) may be a more important indicator of human health risks. In this study, the cytotoxic and genotoxic effects of PM₁.₀ samples from Shanghai were examined using A549 cells, and compared with the effects of PM₂.₅, to better understand the health effects of PM₁.₀ in this area. The PM₁.₀ and PM₂.₅ samples were characterized for morphology, water-soluble inorganic ions, organic and elemental carbon, and metal elements. The cytotoxicity of PMs was measured using cell viability and cell membrane damage assays. The genotoxic effects of PMs were determined using the comet assay, and DNA damage was quantified using olive tail moment (OTM) values. The physicochemical characterization indicated that PM₁.₀ was enriched in carbonaceous elements and hazardous metals (Al, Zn, Pb, Mn, Cu, and V), whereas PM₂.₅ was more abundant in large, irregular mineral particles. The biological results revealed that both PM₁.₀ and PM₂.₅ could induce significant cytotoxicity and genotoxicity in A549 cells, and that exposure to PM₁.₀ caused more extensive toxic effects than exposure to PM₂.₅. The greater cytotoxic effects of PM₁.₀ can be attributed to the combined effects of size and chemical composition, whereas the genotoxic effects of PM₁.₀ may be mainly associated with chemical species.
Afficher plus [+] Moins [-]Impacts of potassium ferrate(VI) on the growth and organic matter accumulation, production, and structural changes in the cyanobacterium Microcystis aeruginosa Texte intégral
2017
Liu, Shuyu | Xu, Jingling | Chen, Wen-li | David, Berthold E. | Wu, Minghong | Ma, Fang
Cyanobacterial blooms generated by nutrient addition into aquatic systems pose serious risks to ecosystems and human health. Though there are established chemical, physical, and biological means of eradication, more efficient and environmentally friendly measures are desired. This study investigates the effect of potassium ferrate(VI) on the growth and intracellular and extracellular organic matter accumulations of the cyanobacterium Microcystis aeruginosa. Cultures were inoculated with three separate concentrations of potassium ferrate(VI) (3, 15, 30 mg L⁻¹) and monitored by measuring chlorophyll-a (Chl-a) and intracellular/extracellular dissolved organic carbon. Results show that ferrate(VI) addition effectively removed the microalgae from the medium, as indicated by the reduction of Chl-a. Organic matter accumulation of the microalgae was also affected by ferrate(VI) treatment; fluorescence EEM spectra show details of changing intracellular dissolved organic matter (IDOM) and extracellular dissolved organic matter (EDOM). A new peak appeared in the EDOM indicating altered humic and proteinaceous compounds. This study demonstrates that ferrate(VI) is a potential treatment for the water contaminated with the toxic microalgae M. aeruginosa.
Afficher plus [+] Moins [-]Indoor air quality in public utility environments—a review Texte intégral
2017
Śmiełowska, Monika | Marć, Mariusz | Zabiegała, Bożena
Indoor air quality has been the object of interest for scientists and specialists from the fields of science such as chemistry, medicine and ventilation system design. This results from a considerable number of potential factors, which may influence the quality of the broadly understood indoor air in a negative way. Poor quality of indoor air in various types of public utility buildings may significantly affect an increase in the incidence of various types of civilisation diseases. This paper presents information about a broad spectrum of chemical compounds that were identified and determined in the indoor environment of various types of public utility rooms such as churches, museums, libraries, temples and hospitals. An analysis of literature data allowed for identification of the most important transport paths of chemical compounds that significantly influence the quality of the indoor environment and thus the comfort of living and the health of persons staying in it.
Afficher plus [+] Moins [-]Impact of thyme powder (Thymus vulgaris L.) supplementation on gene expression profiles of cytokines and economic efficiency of broiler diets Texte intégral
2017
Hassan, Fardos A. M. | Awad, Ashraf
This study was conducted in an attempt to evaluate the impact of thyme powder supplementation on broiler diets with respect to cytokine and mucin2 gene expressions. It was also our aim to evaluate the growth performance, blood biochemical and hematological profiles, and economic efficiency of the diet. A total of 120 1-day old chicks (Cobb 500) were divided into four groups on the basis of the diet. One group received a basal diet (control) while the others received a basal diet supplemented with 2, 5, or 8 g/kg of thyme powder. At 42 days of age, the chickens were weighed and euthanized, and then blood and tissue samples were collected for the purpose of analysis. Results obtained clearly indicated that thyme supplementation of the diet, especially at 5 g/kg, resulted in a significant increase in body weight and caused the increased body weight gain and feed intake (P ˂ 0.05) as well as augmented WBC and lymphocyte count and IgG and NO levels (P ˂ 0.001). The economic evaluation showed that birds fed on 8 g/kg thyme yielded the lowest net revenue and highest feed cost to produce 1 kg of live weight compared to the other treatments, while birds fed on 2 and 5 g/kg thyme did not differ significantly from values obtained for the controls. The lipid profile of the broilers was affected by thyme supplementation at 2 and 5 g/kg as represented by a significant decrease in serum cholesterol levels as well as low density lipoprotein levels, which is known to be associated with a corresponding increase in high-density lipoprotein (P ˂ 0.001). Furthermore, supplementation of thyme downregulated the pro-inflammatory mediators and increased the expression of mucin2 mRNA in the jejunum of chickens. It can be concluded that thyme supplementation in the diet of broilers at 5 g/kg has the potential to favorably influence productive performance via an improvement in the immune status of the broiler.
Afficher plus [+] Moins [-]Distribution and risk assessment of heavy metals in sewage sludge after ozonation Texte intégral
2017
Zhang, Jian | Tian, Yu | Zhang, Jun | Li, Ning | Kong, Lingchao | Yu, Ming | Zuo, Wei
In this paper, transformation of chemical forms of heavy metals (Cu, Zn, Ni, Pb, Cr, Cd, Mn, and Mg) in sewage sludge (SS) during ozonation was investigated. Meanwhile, the risk of heavy metals to environment in ozonated sludge (OS) and SS was estimated according to risk assessment code (RAC). The residual rates of heavy metals were over 72.8 %, which demonstrated that the heavy metals in SS were mainly existed in the OS after ozonation. The results indicated that the ozonation had an effect on the redistribution of heavy metals. The comparisons of the RAC between OS and SS indicated that the environmental risk of heavy metals in OS was aggravated compared to SS, except for Mg. Consequently, it was suggested that the OS should be pretreated before application.
Afficher plus [+] Moins [-]Heavy metal and polycyclic aromatic hydrocarbon concentrations in Quercus ilex L. leaves fit an a priori subdivision in site typologies based on human management Texte intégral
2017
De Nicola, Flavia | Baldantoni, Daniela | Maisto, Giulia | Alfani, Anna
Concentrations of four heavy metals (HMs) (Cd, Cr, Fe, Pb) and four polycyclic aromatic hydrocarbons (PAHs) (fluoranthene, phenanthrene, chrysene, benzo[a]pyrene) in Quercus ilex L. leaves collected at the Campania Region (Southern Italy) in previous air biomonitoring studies were employed to (1) test the correspondence with an a priori site subdivision (remote, periurban, and urban) and (2) evaluate long temporal trends of HM (approximately 20 years) and PAH (approximately 10 years) air contaminations. Overall, Q. ilex leaf HM and PAH concentrations resulted along the gradient: remote < periurban < urban sites, reflecting the a priori subdivision based on human management. Over a long time, although a clear decrease of leaf Pb, chrysene, fluoranthene, and phenanthrene concentrations occurred at the urban sites, a high contamination level persists.
Afficher plus [+] Moins [-]Adsorption of As(III) versus As(V) from aqueous solutions by cerium-loaded volcanic rocks Texte intégral
2017
Asere, Tsegaye Girma | Verbeken, Kim | Tessema, Dejene A. | Fufa, Fekadu | Stevens, Christian V. | Du Laing, Gijs
Contamination of drinking water with arsenic causes severe health problems in various world regions. Arsenic exists predominantly as As(III) and As(V) depending on the prevailing redox conditions of the environment. Most of the techniques developed for treating As(V) are not very effective for As(III), which is more toxic and mobile than As(V). In this study, novel cerium-loaded pumice (Ce-Pu) and red scoria (Ce-Rs) adsorbents were developed to remove both As(III) and As(V) ions from water. The Ce-Pu and Ce-Rs adsorbents were characterized using ICP-OES, EDX, and SEM. The experimental equilibrium sorption data fitted well Freundlich and Dubinin-Radushkevich (D-R) isotherms. The adsorption was very fast and reached an equilibrium within 2 h. Both Ce-Rs and Ce-Pu showed high As(III) and As(V) removal efficiency in a wide pH range between 3 and 9, which is an important asset for practical applications. The Ce-Pu and Ce-Rs adsorbents can be recycled and used up to three adsorption cycles without significant loss of their original efficiency. Accordingly, Ce-Pu and Ce-Rs seem to be suitable for removal of arsenic from aqueous systems.
Afficher plus [+] Moins [-]Evaluation of the performances of a biological treatment on tin-enriched bronze Texte intégral
2017
Albini, Monica | Chiavari, Cristina | Bernardi, Elena | Martini, Carla | Mathys, Lidia | Joseph, Edith
Recently, research gives emphasis to eco-friendly and sustainable approaches for the preservation of cultural heritage that could offer advantages in terms of compatibility, durability and safety. Hence, a biological treatment, based on a specific fungal strain of Beauveria bassiana, is exploited for the stabilization of soluble and/or active bronze corrosion products, converting them into copper oxalates. The chemical stability of the latter represents a real improvement for the long-term preservation of bronze, especially in case of exposure to acid rain. However, the corrosion behaviour of bronze differs from that of pure copper due to the presence of additional alloying elements. In natural environments, the selective dissolution of copper leads to a relative tin-enrichment within the corrosion layers, mostly in unsheltered areas exposed to rainwater runoff. To understand the influence of tin-enrichment on the formation of oxalates, pure tin and artificially tin-enriched bronze coupons were treated with this novel biological system and, in the case of bronze coupons, exposed to accelerated ageing. Tin enrichment and accelerated ageing were performed through runoff tests. Before and after treatment and ageing, the sample surface was characterized through Fourier transform infrared (FTIR) and Raman spectroscopies, scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS). Metals released in the ageing solutions were analysed through atomic absorption spectrometry (AAS). The analytical results allowed to better understand the response of unsheltered areas from outdoor bronze monuments to the biological treatment proposed.
Afficher plus [+] Moins [-]Examining predictors of chemical toxicity in freshwater fish using the random forest technique Texte intégral
2017
Tuulaikhuu, Baigal-Amar | Guasch, Helena | García-Berthou, Emili
Chemical pollution is one of the main issues globally threatening the enormous biodiversity of freshwater ecosystems. The toxicity of substances depends on many factors such as the chemical itself, the species affected, environmental conditions, exposure duration, and concentration. We used the random forest technique to examine the factors that mediate toxicity in a set of widespread fishes and analyses of covariance to further assess the importance of differential sensitivity among fish species. Among 13 variables, the 5 most important predictors of toxicity with random forests were, by order of importance, the chemical substance itself (i.e., Chemical Abstracts Service number considered as a categorical factor), octanol-water partition coefficient (log P), pollutant prioritization, ecological structure-activity relationship (ECOSAR) classification, and fish species for 50% lethal concentrations (LC₅₀) and the chemical substance, fish species, log P, ECOSAR classification, and water temperature for no observed effect concentrations (NOECs). Fish species was a very important predictor for both endpoints and with the two contrasting statistical techniques used. Different fish species displayed very different relationships with log P, often with different slopes and with as much importance as the partition coefficient. Therefore, caution should be exercised when extrapolating toxicological results or relationships among species. In addition, further research is needed to determine species-specific sensitivities and unravel the mechanisms behind them.
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