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Influence of a Reclaimed Sand Addition to Moulding Sand with Furan Resin on Its Impact on the Environment Texto completo
2016
Holtzer, Mariusz | Dańko, Rafał | Kmita, Angelika
Metalcasting involves having a molten metal poured in a hollow mould to produce metal objects. These moulds are generally made of sand and are chemically bonded, clay-bonded, or even unbounded. There are many binder systems used. Binders based on furfuryl resins constitute currently the highest fraction in the binders no-bake group. Moulding sand, after knocking out the cast, is partially reclaimed, and the remaining part, known as waste foundry sand is used or stored outside the foundry. In this case, the environment hazardous organic compounds and metals can be leached from the moulding sand, thus causing pollution of water and soil. Also during the casting moulds with molten metal, they emit pyrolysis gases containing many different compounds, often dangerous from the BTEX and PAH group, which has adverse impacts on the environment and workers. The article presents the results of research on the impact of the regenerate addition to the moulding sand matrix on emitted gases and the degree of threat to the environment due to leaching of hazardous components. Therefore, for the total assessment of the moulding sands harmfulness, it is necessary to perform investigations concerning the dangerous substances elution into the environment during their management and storage, as well as investigations concerning emissions of hazardous substances (especially from the BTEX and PAHs group) during moulds pouring, cooling, and casting knocking out. Both kinds of investigations indicated that reclaimed sand additions to moulding sands have significantly negative influence on the environment and working conditions.
Mostrar más [+] Menos [-]Degradation of Diuron by Electrochemically Activated Persulfate Texto completo
2016
Yu, Yanghai | Zhou, Shiqing | Bu, Lingjun | Shi, Zhou | Zhu, Shumin
An electrochemically activated persulfate (EC/PS) system was proposed for the degradation of herbicide diuron in this study. In the EC/PS system, the ferrous ions (Fe²⁺) produced from iron electrode can activate persulfate to generate sulfate radical (SO₄ ·⁻) as well as hydroxyl radical (OH•). The results showed that the degradation of diuron was significantly enhanced in the EC/PS system, compared to electrocoagulation, persulfate, and Fe²⁺/PS process. Both of SO₄ ·⁻ and OH· contributed to the degradation of diuron in the EC/PS system according to the radical scavenging studies. The pseudo first-order rate constants of diuron increased with increasing the applied currents and dosages of persulfate. pH affected the degradation of diuron indirectly through the speciation of iron and resulted in higher removal efficiency in acidic condition than in alkaline condition. Chloride, carbonate, and bicarbonate in real water inhibited the degradation of diuron dramatically through consuming SO₄ ·⁻ and OH· and abided by the order of CO₃ ²⁻>HCO₃ ⁻>Cl⁻. This study demonstrates that the EC/PS system is a novel, efficient, promising, and environmental-friendly method to treat diuron contamination.
Mostrar más [+] Menos [-]Hydrolytic-Acidogenic Fermentation of Organic Solid Waste for Volatile Fatty Acids Production at Different Solids Concentrations and Alkalinity Addition Texto completo
2016
Gameiro, Tânia | Lopes, Maria | Marinho, Rita | Vergine, Pompilio | Nadais, Helena | Capela, Isabel
Intermediate products from anaerobic fermentation, such as volatile fatty acids (VFA), are the preferred carbon sources for the production of added-value products, namely polyhydroxyalkanoates (PHA) or bioenergy. Organic fraction of municipal solid waste (OFMSW) can be valorized through the application of a hydrolytic-acidogenic stage, thus reducing its pollutant content and at the same time that it is obtaining high-value products (VFA). In this work, the anaerobic fermentation of OFMSW into VFA (production and profile) and the influence of both total solids (TS) content in the reactor and alkalinity addition were studied. The increase on TS content led to a decrease on the acidification degree whereas the increase on the alkalinity addition led to a higher degree of acidification. Hence, the highest degree of acidification (77.59 %) was obtained at the lowest TS content (5 %) and at the highest alkalinity addition (50 g CaCO3 L⁻¹). However, depending on the ultimate use of the produced VFA, the acidified residue presenting the highest VFA content (98.96 %) with higher propionic acid concentration, which is a more suitable VFA mixture for the production of high-quality PHA, was obtained at an intermediate TS content (8 %). From the response surfaces obtained, it was observed that all response variables (VFA production, degree of acidification, and effluent quality) presented a higher dependency on TS content than on initial alkalinity addition.
Mostrar más [+] Menos [-]Simulating the Transfer of Strontium-90 from Soil to Leafy Vegetables by Using Strontium-88 Texto completo
2016
Kuke, Ding | Shujuan, Liu | Yingxue, He | Dong, Yan | Fengshou, Zhang | Shuifeng, Wang | Jinghua, Guo | Wei, Zhang | Xinwang, | Xiaoyan, Jiang
The transfer, from soil to Chinese cabbage and spinach, of radioactive strontium-90 released as a result of accidents in nuclear power stations was studied using a stable isotope of strontium, namely nuclide strontium-88 (⁸⁸Sr). The study led to an experimental model for assessing the hazard of radionuclide strontium-90 (⁹⁰Sr) entering the food chain and for predicting the risk to food safety. Chinese cabbage and spinach were grown in pots in a greenhouse and irrigated with deionized water containing known quantities of strontium. Based on the strontium content of that water, the plants were divided into five groups (treatments) and strontium content of the soil, and 30-day-old plants were determined by inductively coupled plasma atomic emission spectroscopy instrument (ICP-AES). Data on the strontium content of soil and plants enabled the development of a model using MATLAB, a mathematical software package, which included curve fitting and problem solving using regression equations and differential equations. Although strontium curves for leaves, stems, and roots of Chinese cabbage were not exactly the same, all showed a non-linear increase when compared with the increase in the content of strontium in soil. Strontium curves for leaves, stems, and roots of spinach were very similar and showed an initial increase followed by a decrease. Strontium concentrations in both Chinese cabbage and spinach were initially related to the concentrations of sodium and sulfur, the next two relevant nuclides being calcium and magnesium. The relationship between calcium and strontium in Chinese cabbage was different from that in spinach. By using ⁸⁸Sr to simulate the transfer of radionuclide ⁹⁰Sr from soil to a crop, the relevant data required to deal with accidental release of strontium can be obtained using a fitting curve and regression equations, thereby providing some experimental basis for evaluating the potential hazards posed by such accidents to the food chain.
Mostrar más [+] Menos [-]Endocrine-Disrupting Chemicals: Adverse Effects of Bisphenol A and Parabens to Women’s Health Texto completo
2016
Jagne, Jabou | White, Dominique | Jefferson, Felicia
Endocrine-disrupting chemicals (EDCs) have the ability to inhibit normal hormonal levels and may exert an array of inimical consequences in human health. These toxins have special adverse effects in women. This review summarizes recent literature reporting on endocrine-disrupting chemicals, specifically the effects induced by parabens from personal care products and cosmetics, and bisphenol A (BPA) found in food containers, with association to adverse effects on women’s health. Finally, the review provides recommendation on utilizing such EDCs to better meet the needs of consumers, while avoiding these chemical modifiers.
Mostrar más [+] Menos [-]Environmentally Relevant Concentrations of TiO2 Nanoparticles Affected Cell Viability and Photosynthetic Yield in the Chlorophyceae Scenedesmus bijugus Texto completo
2016
Barreto, DanielaMariano | Lombardi, AnaTeresa
The impact of nanoparticles (NPs) in phytoplankton is understudied, particularly with respect to the organism’s physiology and environmentally relevant concentrations. In the present research, we investigated the effects of titanium dioxide nanoparticles (nano-TiO₂) in the physiology of Scenedesmus bijugus, a freshwater cosmopolitan phytoplankter, exposed to concentrations ranging from 3.30 × 10⁻⁹ mol L⁻¹ (log −8.48) to 3.70 × 10⁻⁷ mol L⁻¹ (log −6.43), which includes environmentally relevant values. The nano-TiO₂ concentrations in the medium and in the cells were determined in experiments that lasted 96 h. Controlled environmental conditions were used throughout and a variety of endpoints were monitored. These included cell density, cell viability, chlorophyll a concentration, growth rates, maximum quantum yield of photosystem II (ΦM), intracelular proteins and carbohydrates, and proteins:carbohydrates ratios. The results showed that cell viability was the most sensitive parameter for the detection of the nano-TiO₂ effects, being followed by ΦM. At the concentration of 3.90 × 10⁻⁸ mol L⁻¹ (log −7.40), there was an increase of nano-TiO₂ injured cells, and at 3.70 × 10⁻⁷ mol L⁻¹ (log −6.43) 24%, ΦM decrease in comparison with the controls was obtained. Different from several literature results, we showed that nano-TiO₂ particles at environmentally relevant concentrations affected microalgae physiology, and this was dependent on the endpoint used to evaluate the effect.
Mostrar más [+] Menos [-]The Accumulation Potency of Bulk and Nano Zinc Metal and Their Impacts on the Hematological and Histological Perturbations of Oreochromis niloticus Texto completo
2016
Abdel-Khalek, Amr Adel | Hamed, Aliaa | Marie, Mohamed-Assem
This study was carried out to comparatively evaluate the bioaccumulation potency of Zn bulk and nanoparticles in Oreochromis niloticus and to investigate the induced hematological and histological alterations. Fish were exposed to ½ LC50/96 h values of both bulk and nano Zn meal for 7, 14, and 28 days. Concerning metal bioaccumulation factor (BAF), the data displayed that zinc nanoparticles (Zn NPs) had more efficiency to penetrate the studied tissues such as the liver, kidneys, gills, skin, and muscle. Hematological parameters named red blood cells (RBC), hemoglobin (Hb), and hematocrit (Hct) values were altered in Zn NPs treated groups after 14th and 28th days while these hematological parameters recovered to some extent in bulk particles (BPs) treated groups at the end of the experimental period. The changes in hematological parameters were found to be time dependent. Blood indices such as mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) revealed the presence of normocytic normochromic anemia in the studied groups at the most exposure periods except microcytic hypochromic anemia at the 7th day of bulk particles exposed fish. Based on histological end points, several alterations in the gills, liver, and kidney tissues were observed. Severely deformations were observed at NPs treated fish groups which varied between adaptive changes to tissue damage at the end of exposure period. The deformations were recorded to be increased in NPs exposed fish compared to BPs treated fish throughout the study periods.
Mostrar más [+] Menos [-]Integrated Geochemistry, Isotopes, and Geostatistical Techniques to Investigate Groundwater Sources and Salinization Origin in the Sharm EL-Shiekh Area, South Sinia, Egypt Texto completo
2016
Isawi, Heba | El-Sayed, Magdi H. | Eissa, Mustafa | Shouakar-Stash, Orfan | Shawky, Hosam | Abdel Mottaleb, Mohamed S.
The Sharm El-Sheikh area is one of the most attractive touristic resorts in Egypt and in the world in general. The Sharm El-Shiekh area is located at the arid region of the South Sinai Peninsula, Egypt. Water desalination is considered the main freshwater supply for hotels and resorts. Scarcity of rainfall during the last decades, high pumping rates, disposal of reject brine water back into the aquifer, and seawater intrusion have resulted in the degradation of groundwater quality in the main aquifer. Water chemistry, stable isotopes, Seawater Mixing Index (SWMI), and factorial analyses were utilized to determine the main recharge and salinization sources as well as to estimate the mixing ratios between different end members affecting groundwater salinity in the aquifer. The groundwater of the Miocene aquifer is classified into two groups: group I represents 10 % of the total samples, has a moderately high saline groundwater, and is mostly affected by seawater intrusion. Group II represents 90 % of the total samples and has a high groundwater salinity due to the anthropological impact of the reject brine saline water deeper into the Miocene aquifer. The main groundwater recharge comes from the western watershed mountain and the elevated plateau while the seawater and reject brine are considering the main sources for groundwater salinization. The mixing ratios between groundwater recharge, seawater, and reject brine water were calculated using water chemistry and isotopes. The calculated mixing ratios of group I range between 25 and 84 % recharge groundwater to 75 and 16 % seawater, respectively, in groundwater located close to the western watershed mountain indicating further extension of seawater intrusion. However, the mixing percentages of group II range between 21 and 88 % reject brine water to 79 and 12 % seawater, respectively, in groundwater located close to the desalination plants. The outcomes and conclusion of this study highlight the importance of groundwater management to limit further groundwater deterioration of the Miocene groundwater aquifer and limit seawater intrusion along the coast.
Mostrar más [+] Menos [-]Toxicities of 48 pharmaceuticals and their freshwater and marine environmental assessment in northwestern France Texto completo
2016
Minguez, Laetitia | Pedelucq, Julie | Farcy, Emilie | Ballandonne, Céline | Budzinski, Hélène | Halm-Lemeille, Marie-Pierre
A risk assessment for freshwater and marine ecosystems is presented for 48 pharmaceutical compounds, belonging to 16 therapeutic classes, and prescribed in northwestern France. Ecotoxicity data were obtained on two freshwater organisms, i.e., crustacean Daphnia magna and the green algae Pseudokirchneriella subcapitata, and on two marine organisms, i.e., the crustacean Artemia salina and the diatom Skeletonema marinoi. Measured environmental concentrations (MEC), in the Orne River and sea off Merville-Franceville in the Basse-Normandie region, were compared to the predicted environmental concentrations (PEC). Predicted no-effect concentrations (PNEC) were derived from acute data for each compound. Then, a risk assessment for each compound and the mixture was performed by calculating risk quotients (RQ as PEC or MEC/PNEC ratio). Results showed that no immediate acute toxicities were expected even if some compounds displayed strong toxicities at very low concentrations. Antibiotics, antidepressants, and antifungals would deserve attention because of their high or median ecological risk suspected on marine and freshwater ecosystems. Marine ecosystems would be more sensitive to pharmaceutical residues.
Mostrar más [+] Menos [-]Growth and Cadmium Accumulation of Solanum nigrum L. Seedling were Enhanced by Heavy Metal-Tolerant Strains of Pseudomonas aeruginosa Texto completo
2016
Shi, Peili | Zhu, Kangxing | Zhang, Yuxiu | Chai, Tuanyao
Some heavy metal-tolerant bacteria recognized as plant growth-promoting bacteria (PGPB) could improve plant growth. Here, the growth and Cd accumulation of Solanum nigrum seedling inoculated by soaking the roots in a dilute suspension of the Cd-tolerant strains ZGKD5 or ZGKD2 were investigated. The results showed that both ZGKD5 and ZGKD2 exhibited the characterization of producing IAA, siderophores, ammonia, and biosurfactant, and solubilizing phosphate and fixing nitrogen. The siderophores produced by both strains could chelate various heavy metals, such as Cu, Cd, Zn, and Ni. The shoot height, root length, number of fibrous root, and dry weight of S. nigrum seedling were significantly increased by inoculation with ZGKD5 or ZGKD2 in the absence or presence of Cd stress. The Cd concentration and translocation from root to shoot in seedlings were remarkably increased, indicating that both strains could improve the growth and Cd phytoextraction of S. nigrum. The activities of SOD, POD, CAT, and APX in both inoculated and uninoculated plants were increased under Cd stress, indicating that these antioxidative enzymes could alleviate oxidative stress induced by Cd. Furthermore, activities of antioxidative enzyme in inoculated plants exposed to Cd stress was lower than that in uninoculated Cd-stressed plants, which might be due to the decreasing metabolism caused by high levels of Cd. These results indicated that strains ZGKD5 and ZGKD2 are PGPB and have the potential for improving the phytoremediation of S. nigrum in Cd-contaminated farmland soil.
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