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Результаты 1451-1460 из 2,459
Degradation of the potential rodent contraceptive quinestrol and elimination of its estrogenic activity in soil and water
2014
Zhang, Quan | Wang, Cui | Liu, Wanpeng | Qu, Jiapeng | Liu, Ming | Zhang, Yanming | Zhao, Meirong
Quinestrol has shown potential for use in the fertility control of the plateau pika population of the Qinghai–Tibet Plateau. However, the environmental safety and fate of this compound are still obscure. Our study investigated degradation of quinestrol in a local soil and aquatic system for the first time. The results indicate that the degradation of quinestrol follows first-order kinetics in both soil and water, with a dissipation half-life of approximately 16.0 days in local soil. Microbial activity heavily influenced the degradation of quinestrol, with 41.2 % removal in non-sterile soil comparing to 4.8 % removal in sterile soil after incubation of 10 days. The half-lives in neutral water (pH 7.4) were 0.75 h when exposed to UV light (λ = 365 nm) whereas they became 2.63 h when exposed to visible light (λ > 400 nm). Acidic conditions facilitated quinestrol degradation in water with shorter half-lives of 1.04 and 1.47 h in pH 4.0 and pH 5.0 solutions, respectively. Moreover, both the soil and water treatment systems efficiently eliminated the estrogenic activity of quinestrol. Results presented herein clarify the complete degradation of quinestrol in a relatively short time. The ecological and environmental safety of this compound needs further investigation.
Показать больше [+] Меньше [-]Interactive effects of different inorganic As and Se species on their uptake and translocation by rice (Oryza sativa L.) seedlings
2014
Hu, Ying | Duan, Gui-Lan | Huang, Yi-Zong | Liu, Yun-Xia | Sun, Guo-Xin
There is a lack of information on the interactive relationship of absorption and transformation between two inorganic arsenic (As) species and two inorganic selenium (Se) species in rice grown under hydroponic condition. Interactive effects of inorganic As (As(III)) and (As(V)) and Se (Se(IV)and Se(VI)) species on their uptake, accumulation, and translocation in rice (Oryza sativa L.) seedlings were investigated in hydroponic culture. The results clearly showed the interactive effects of inorganic As and Se on their uptake by rice. The presence of Se reduced the sum of As species in the rice shoots regardless of Se speciation. If Se is present as Se(IV), then is it is accompanied by a corresponding increase of the sum of As species, but if Se is present as Se(VI), then there is no change in the sum of As species in rice roots. These effects are observed regardless of initial As speciation. When the rice plants are exposed to Se(IV), the presence of As increases the sum of Se species in the roots, and decreases the sum of Se species in the corresponding shoots. This effect is more pronounced for As(III) than for As(V). There is no effect on Se during exposure to Se(VI). Co-existence of As also increased SeMet in rice roots.
Показать больше [+] Меньше [-]Pollution due to hazardous glass waste
2014
Pant, Deepak | Singh, Pooja
Pollution resulting from hazardous glass (HG) is widespread across the globe, both in terms of quantity and associated health risks. In waste cathode ray tube (CRT) and fluorescent lamp glass, mercury and lead are present as the major pollutants. The current review discusses the issues related to quantity and associated risk from the pollutant present in HG and proposes the chemical, biological, thermal, hybrid, and nanotechniques for its management. The hybrid is one of the upcoming research models involving the compatible combination of two or more techniques for better and efficient remediation. Thermal mercury desorption starts at 100 °C but for efficient removal, the temperature should be >460 °C. Involvement of solar energy for this purpose makes the research more viable and ecofriendly. Nanoparticles such as Fe, Se, Cu, Ni, Zn, Ag, and WS₂alone or with its formulation can immobilize heavy metals present in HG by involving a redox mechanism. Straight-line equation from year-wise sale can provide future sale data in comparison with lifespan which gives future pollutant approximation. Waste compact fluorescent lamps units projected for the year 2015 is 9,300,000,000 units and can emit nearly 9,300 kg of mercury. On the other hand, CRT monitors have been continuously replaced by more improved versions like liquid crystal display and plasma display panel resulting in the production of more waste. Worldwide CRT production was 83,300,000 units in 2002 and can approximately release 83,000 metric tons of lead.
Показать больше [+] Меньше [-]Impact of wastewater treatment plants on receiving surface waters and a tentative risk evaluation: the case of estrogens and beta blockers
2014
Gabet-Giraud, V. | Miège, C. | Jacquet, R. | Coquery, M.
Five estrogenic hormones (unconjugated + conjugated fractions) and 10 beta blockers were analyzed in three wastewater treatment plant (WWTP) effluents and receiving river waters in the area of Lyon, France. In the different samples, only two estrogens were quantified: estrone and estriol. Some beta blockers, such as atenolol, acebutolol, and sotalol, were almost always quantified, but others, e.g., betaxolol, nadolol, and oxprenolol were rarely quantified. Concentrations measured in river waters were in the nanogram per liter range for estrogens and between 0.3 and 210 ng/L for beta blockers depending on the substance and the distance from the WWTP outfall. The impact of the WWTP on the receiving rivers was studied and showed a clear increase in concentrations near the WWTP outfall. For estrogens, the persistence in surface waters was not evaluated given the low concentrations levels (around 1 ng/L). For beta blockers, concentrations measured downstream of the WWTP outfall were up to 16 times higher than those measured upstream. Also, the persistence of metoprolol, nadolol, and propranolol was noted even 2 km downstream of the WWTP outfall. The comparison of beta blocker fingerprints in the samples collected in effluent and in the river also showed the impact of WWTP outfall on surface waters. Finally, a tentative environmental risk evaluation was performed on 15 sites by calculating the ratio of receiving water concentrations to predicted non-effect concentrations (PNEC). For estrogens, a total PNEC of 5 ng/L was considered and these substances were not linked to any potential environmental risk (only one site showed an environmental risk ratio above 1). Unfortunately, few PNECs are available and risk evaluation was only possible for 4 of the 10 beta blockers studied: acebutolol, atenolol, metoprolol, and propranolol. Only propranolol presented a ratio near or above 1, showing a possible environmental risk for 4 receiving waters out of 15.
Показать больше [+] Меньше [-]Particle size distribution of n-alkanes and polycyclic aromatic hydrocarbons (PAHS) in urban and industrial aerosol of Algiers, Algeria
2014
Ladji, R. | Yassaa, N. | Balducci, C. | Cecinato, A.
The distribution of ambient air n-alkanes and polycyclic aromatic hydrocarbons (PAHs) associated to particles with aerodynamic diameters lesser than 10 μm (PM₁₀) into six fractions (five stages and a backup filter) was studied for the first time in Algeria. Investigation took place during September of 2007 at an urban and industrial site of Algiers. Size-resolved samples (<0.49, 0.49–0.95, 0.95–1.5, 1.5–3.0, 3.0–7.2, and7.2–10 μm) were concurrently collected at the two sampling sites using five-stage high-volume cascade impactors. Most of n-alkanes (~72 %) and PAHs (~90 %) were associated with fine particles ≤1.5 μm in both urban and industrial atmosphere. In both cases, the n-alkane contents exhibited bimodal or weakly bimodal distribution peaking at the 0.95–1.5-μm size range within the fine mode and at 7.3–10 μm in the coarse mode. Low molecular weight PAHs displayed bimodal patterns peaking at 0.49–0.95 and 7.3–10 μm, while high molecular weight PAHs exhibited mono-modal distribution with maximum in the <0.49-μm fraction. While the mass mean diameter of total n-alkanes in the urban and industrial sites was 0.70 and 0.84 μm, respectively, it did not exceed 0.49 μm for PAHs. Carbon preference index (~1.1), wax% (10.1–12.8), and the diagnostic ratios for PAHs all revealed that vehicular emission was the major source of these organic compounds in PM₁₀during the study periods and that the contribution of epicuticular waxes emitted by terrestrial plants was minor. According to benzo[a]pyrene-equivalent carcinogenic power rates, ca. 90 % of overall PAH toxicity across PM₁₀was found in particles ≤0.95 μm in diameter which could induce adverse health effects to the population living in these areas.
Показать больше [+] Меньше [-]Emergy-based comparative analysis on industrial clusters: economic and technological development zone of Shenyang area, China
2014
Liu, Zhe | Geng, Yong | Zhang, Pan | Dong, Huijuan | Liu, Zuoxi
In China, local governments of many areas prefer to give priority to the development of heavy industrial clusters in pursuit of high value of gross domestic production (GDP) growth to get political achievements, which usually results in higher costs from ecological degradation and environmental pollution. Therefore, effective methods and reasonable evaluation system are urgently needed to evaluate the overall efficiency of industrial clusters. Emergy methods links economic and ecological systems together, which can evaluate the contribution of ecological products and services as well as the load placed on environmental systems. This method has been successfully applied in many case studies of ecosystem but seldom in industrial clusters. This study applied the methodology of emergy analysis to perform the efficiency of industrial clusters through a series of emergy-based indices as well as the proposed indicators. A case study of Shenyang Economic Technological Development Area (SETDA) was investigated to show the emergy method’s practical potential to evaluate industrial clusters to inform environmental policy making. The results of our study showed that the industrial cluster of electric equipment and electronic manufacturing produced the most economic value and had the highest efficiency of energy utilization among the four industrial clusters. However, the sustainability index of the industrial cluster of food and beverage processing was better than the other industrial clusters.
Показать больше [+] Меньше [-]Tire tread wear particles in ambient air—a previously unknown source of human exposure to the biocide 2-mercaptobenzothiazole
2014
Avagyan, Rozanna | Sadiktsis, Ioannis | Bergvall, Christoffer | Westerholm, Roger
Urban particulate matter (PM), asphalt, and tire samples were investigated for their content of benzothiazole and benzothiazole derivates. The purpose of this study was to examine whether wear particles, i.e., tire tread wear or road surface wear, could contribute to atmospheric concentrations of benzothiazole derivatives. Airborne particulate matter (PM₁₀) sampled at a busy street in Stockholm, Sweden, contained on average 17 pg/m³ benzothiazole and 64 pg/m³ 2-mercaptobenzothiazole, and the total suspended particulate-associated benzothiazole and 2-mercaptobenzothiazole concentrations were 199 and 591 pg/m³, respectively. This indicates that tire tread wear may be a major source of these benzothiazoles to urban air PM in Stockholm. Furthermore, 2-mercaptobenzothiazole was determined in urban air particulates for the first time in this study, and its presence in inhalable PM₁₀ implies that the human exposure to this biocide is underestimated. This calls for a revision of the risk assessments of 2-mercaptobenzothiazole exposure to humans which currently is limited to occupational exposure.
Показать больше [+] Меньше [-]Investigation of the antibacterial effects of silver-modified TiO₂ and ZnO plasmonic photocatalysts embedded in polymer thin films
2014
Tallósy, Szabolcs Péter | Janovák, László | Ménesi, Judit | Nagy, Elisabeth | Juhász, Ádám | Balázs, László | Deme, István | Buzás, Norbert | Dékány, Imre
Nanosilver-modified TiO₂ and ZnO photocatalysts were studied against methicillin-resistant Staphylococcus aureus on the surface and against naturally occurring airborne microorganisms. The photocatalysts/polymer nanohybrid films were prepared by spray coating technique on the surface of glass plates and on the inner surface of the reactive light source. The photoreactive surfaces were activated with visible light emitting LED light at λ = 405 nm. The optical properties of the prepared photocatalyst/polymer nanohybrid films were characterized by diffuse reflectance measurements. The photocatalytic properties were verified with the degradation of ethanol by gas chromatography measurements. The destruction of the bacterial cell wall component was examined with transmission electron microscope. The antibacterial effect of the photocatalyst/polymer nanohybrid films was tested with different methods and with the associated standard ISO 27447:2009. With the photoreactive coatings, an extensive disinfectant film was developed and successfully prepared. The cell wall component of S. aureus was degraded after 1 h of illumination. The antibacterial effect of the nanohybrid films has been proven by measuring the decrease of the number of methicillin-resistant S. aureus on the surface and in the air as the function of illumination time. The photocatalyst/polymer nanohybrid films could inactivate 99.9 % of the investigated bacteria on different thin films after 2 h of illumination with visible light source. The reactive light source with the inner-coated photocatalyst could kill 96 % of naturally occurring airborne microorganisms after 48 h of visible light illumination in indoor air sample. The TEM results and the microbiological measurements were completed with toxicity tests carried out with Vibrio fischeri bioluminescence bacterium.
Показать больше [+] Меньше [-]Competitive removal of pharmaceuticals from environmental waters by adsorption and photocatalytic degradation
2014
Rioja, N. | Benguria, P. | Peñas, F. J. | Zorita, S.
This work explores the competitive removal of pharmaceuticals from synthetic and environmental waters by combined adsorption-photolysis treatment. Five drugs usually present in waterways have been used as target compounds, some are pseudo-persistent pollutants (carbamazepine, clofibric acid, and sulfamethoxazole) and others are largely consumed (diclofenac and ibuprofen). The effect of the light source on adsorption of drugs onto activated carbons followed by photolysis with TiO₂ was assessed, being UV-C light the most effective for drug removal in both deionized water and river water. Different composites prepared from titania nanoparticles and powdered activated carbons were tested in several combined adsorption-photocatalysis assays. The composites prepared by calcination at 400 °C exhibited much better performance than those synthesized at 500 °C, being the C400 composite the most effective one. Furthermore, some synthetic waters containing dissolved species and environmental waters were used to investigate the effect of the aqueous matrix on each drug removal. In general, photocatalyst deactivation was found in synthetic and environmental waters. This was particularly evident in the experiments performed with bicarbonate ions as well as with wastewater effluent. In contrast, tests conducted in seawater showed adsorption and photocatalytic degradation yields comparable to those obtained in deionized water. Considering the peculiarities of substrate competition in each aqueous matrix, the combined adsorption-photolysis treatment generally increased the overall elimination of drugs in water.
Показать больше [+] Меньше [-]Influence of sediment composition on PAH toxicity using zebrafish (Danio rerio) and Japanese medaka (Oryzias latipes) embryo-larval assays
2014
Perrichon, Prescilla | Le Bihanic, Florane | Bustamante, Paco | Le Menach, Karyn | Budzinski, Hélène | Cachot, Jérôme | Cousin, Xavier
Due to hydrophobic and persistent properties, polycyclic aromatic hydrocarbons (PAHs) have a high capacity to accumulate in sediment. Sediment quality criteria, for the assessment of habitat quality and risk for aquatic life, include understanding the fate and effects of PAHs. In the context of European regulation (REACH and Water Framework Directive), the first objective was to assess the influence of sediment composition on the toxicity of two model PAHs, benzo[a]pyrene and fluoranthene using 10-day zebrafish embryo-larval assay. This procedure was undertaken with an artificial sediment in order to limit natural sediment variability. A suitable sediment composition might be then validated for zebrafish and proposed in a new OECD guideline for chemicals testing. Second, a comparative study of toxicity responses from this exposure protocol was then performed using another OECD species, the Japanese medaka. The potential toxicity of both PAHs was assessed through lethal (e.g., survival, hatching success) and sublethal endpoints (e.g., abnormalities, PMR, and EROD) measured at different developmental stages, adapted to the embryonic development time of both species. Regarding effects observed for both species, a suitable artificial sediment composition for PAH toxicity testing was set at 92.5 % dry weight (dw) silica of 0.2–0.5-mm grain size, 5 % dw kaolin clay without organic matter for zebrafish, and 2.5 % dw blond peat in more only for Japanese medaka. PAH bioavailability and toxicity were highly dependent on the fraction of organic matter in sediment and of the Kₒwcoefficients of the tested compounds. The biological responses observed were also dependent of the species under consideration. Japanese medaka embryos appeared more robust than zebrafish embryos for understanding the toxicity of PAHs following a sediment contact test, due to the longer exposure duration and lower sensitivity of sediment physical properties.
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