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Результаты 3941-3950 из 5,153
Application of vermiculite-derived sustainable adsorbents for removal of venlafaxine Полный текст
2018
Silva, Andreia | Martinho, Sílvia | Stawiński, Wojciech | Węgrzyn, Agnieszka | Figueiredo, Sónia | Santos, Lúcia H. M. L. M. | Freitas, Olga
Removal of emerging pollutants, such as pharmaceuticals, from wastewater is a challenge. Adsorption is a simple and efficient process that can be applied. Clays, which are natural and low-cost materials, have been investigated as adsorbent. In this work, raw vermiculite and its three modified forms (expanded, base, and acid/base treated) were tested for removal of a widely used antidepressant, venlafaxine. Adsorption kinetics followed Elovich’s model for raw vermiculite while the pseudo-2nd order model was a better fit in the case of other materials. Equilibrium followed Langmuir’s model for the raw and the acid/base-treated vermiculite, while Redlich-Peterson’s model fitted better the expanded and the base-treated materials. The adsorption capacity of vermiculite was significantly influenced by the changes in the physical and chemical properties of the materials caused by the treatments. The base-treated, raw, and expanded vermiculites showed lower maximum adsorption capacities (i.e., 6.3 ± 0.5, 5.8 ± 0.7, 3.9 ± 0.2 mg g⁻¹, respectively) than the acid/base-treated material (33 ± 4 mg g⁻¹). The acid/base-treated vermiculite exhibited good properties as a potential adsorbent for tertiary treatment of wastewater in treatment plants, in particular for cationic species as venlafaxine due to facilitation of diffusion of the species to the interlayer gallery upon such treatment. Graphical abstract ᅟ
Показать больше [+] Меньше [-]Assessment of the inhalation risks associated with working in printing rooms: a study on the staff of eight printing rooms in Beijing, China Полный текст
2018
Su, Mingxing | Sun, Rubao | Zhang, Xun | Wang, Shen | Zhang, Ping | Yuan, Zhengquan | Liu, Chao | Wang, Qiang
The concentration of pollution directly determines the occupational health risk, and the exposure time is an important influencing factor. We evaluated the inhalation risks of working in a printing room. Eight units with centralized printing rooms were randomly selected. Formaldehyde, ozone, benzene, toluene, xylene, and fine particulate matter were detected by spectrophotometry, gas chromatography, and direct reading instruments, respectively. The U.S. EPA inhalation risk assessment model was used to assess cancer and non-cancer risks. The formaldehyde inhalation cancer risk value was 1.35–3.45 × 10⁻⁶, which is greater than the limit of 1 × 10⁻⁶, suggesting a risk of squamous cell carcinoma. The benzene inhalation cancer risk in five of the rooms was 1.09–4.65 × 10⁻⁶, which is greater than the limit of 1 × 10⁻⁶, suggesting a risk of leukemia. In terms of non-cancer risk, in five of the rooms, the hazard quotient (HQ) was > 1 (range 1.99–4.69) due to benzene pollution, suggesting a risk of reduced lymphocyte count. In one room, due to benzene and xylene pollution, the HQ was > 1, suggesting a risk of lymphocyte count drop and motor coordination impairment. Collectively, the study concludes that staff members of printing rooms are exposed to both cancer and non-cancer occupational health risks.
Показать больше [+] Меньше [-]The combined effect of Bassa 50EC and Vitashield 40EC on the brain acetylcholinesterase activity in climbing perch (Anabas testudineus) Полный текст
2018
Tam, Nguyen Thanh | Berg, Håkan | Van Cong, Nguyen
The combined effect of Vitashield 40EC (chlorpyrifos ethyl-CPF) and Bassa 50EC (fenobucarb-F) was compared with the effects from exposure to the two pesticides separately, by measuring the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings (Anabas testudineus). The experiment was conducted under controlled laboratory conditions and included three treatments containing 0.173 mg/L of CPF, 1.137 mg/L of F, 0.173 mg/L of CPF + 1.137 mg/L of F (M), and a control. The inhibition of the brain AChE activity in fish exposed to F was weaker and shorter than in fish exposed to CPF. The inhibition by the mixture of CPF and F was significantly lower and less prolonged than the inhibition by only CPF but significantly higher than the inhibition by only F.
Показать больше [+] Меньше [-]Characteristics and health risk assessment of volatile organic compounds emitted from interior materials in vehicles: a case study from Nanjing, China Полный текст
2018
Xing, Liqun | Wang, Lichao | Zhang, Rui
It has become a great habit for driving to work in people’s daily life in China. In order to understand the concentration of volatile organic compounds (VOCs) in vehicles and the health risks related to inhalation exposure to VOCs, this study investigated the pollution characteristics and health risks posed by VOCs emitted from interior materials in vehicles. A total of 47 of 62 VOCs were studied, using 23 randomly selected vehicles of different brands in Nanjing city, China. The potential cancer and non-cancer health risks associated with VOC inhalation were assessed based on conventional approaches proposed by the United States Environmental Protection Agency (USEPA). The mean concentration of total VOCs was 1126.85 μg/m³, with a range of 321.29 to 2321.94 μg/m³. Of these, halohydrocarbons and aromatic hydrocarbons were the dominant components of the detected VOCs. The concentrations of several individual VOC exceeded more than 100 μg/m³. The individual mean cancer risks for the 17 health-related VOCs ranged from 4.64 × 10⁻¹⁰ to 1.09 × 10⁻⁴, with a cumulative risk of 1.61 × 10⁻⁴. The mean cancer risks associated with naphthalene, chloroform, 1,4-dichlorobenzene, and 1,2-dibromoethylene were 1.09 × 10⁻⁴, 1.61 × 10⁻⁵, 1.11 × 10⁻⁵, and 1.07 × 10⁻⁵, respectively. These risks are higher than the acceptable risk levels defined by the USEPA and the World Health Organization (WHO). Of these, naphthalene was regarded as having a “definite risk”; chloroform, 1,4-dichlorobenzene, and 1,2-dibromoethylene were regarded as having a “probable risk”; and 1,2-dichloroethane and carbon tetrachloride were regarded as having “possible risk.” The individual mean non-cancer risks associated with 28 health-related VOCs and total VOCs were within acceptable ranges; naphthalene was the dominant pollutant.
Показать больше [+] Меньше [-]Elucidation of functional chemical groups responsible of compost phytotoxicity using solid-state 13C NMR spectroscopy under different initial C/N ratios Полный текст
2018
Azim, Khalid | Faissal, Youssef | Soudi, Brahim | Perissol, Claude | Roussos, Sevastianos | Thami Alami, Imane
More than 1 million tons of fresh organic wastes is produced in the Souss-Massa region in Morocco. Tomato organic residues represent more than 25% of the total organic wastes and are deposited in uncontrolled landfills. Thus, composting can represent a valuable and pertinent solution to this environmental problem. The objectives of this experiment are to identify the potential functional groups responsible for compost phytotoxicity and to determine the optimum initial carbon to nitrogen ratio (C/N) for maximum recovery of tomato residues. The experiment consisted of the variation of the initial C/N ratios (25, 30, 35, and 40) using mixtures of different raw materials (tomato residues, melon residues, olive mill pomace, and sheep manure). Physicochemical parameters (pH, electrical conductivity, C/N ratio, and humic acid/fulvic acid ratio) were determined and spectroscopic analyses (UV-vis and NMR-¹³C) were performed during the composting process along with quality parameters (germination and phytotoxicity tests) at the end. The results showed that the compost with the initial C/N ratio of 35 is the most humified with the least phytotoxic effect. The germination and phytotoxicity tests were negatively correlated with the methoxyl/N-alkyl-C ratio and O-alkyl-C. These two functional groups are probably the origin of phytotoxicity expression in compost quality tests. Thus, a simple and precise quality test could be performed to evaluate directly the phytotoxicity and maturity of compost.
Показать больше [+] Меньше [-]Drying–submergence alternation enhanced crystalline ratio and varied surface properties of iron plaque on rice (Oryza sativa) roots Полный текст
2018
Yang, Xu-Jian | Xu, Zhihong | Shen, Hong
Iron plaque (IP) is valuable in nutrient management and contaminant tolerance for rice (Oryza sativa) because it can adsorb various nutrients and toxic ions. Crystalline ratio (CR) can be defined as the proportion of crystalline iron (CI) to total IP to describe IP crystallinity. Although the knowledge on IP has abounded, the information on the relationship among its formation condition, surface properties, and CR remains insufficient. In this study, quartz sand–soil cultivation with rice was conducted to explore the effect of drying–submergence alternation (DSA) on CI, amorphous iron (AI), CR, root oxidizing capacity (ROC), and surface properties of IP with different treatment durations and at different stages. Fourteen-day DSA treatment increased CI to 2.20 times of that after continuous submergence (CS) but decreased AI to 72.3% of that after CS. Correspondingly, CR was raised to 6.89% from 4.08%. Remarkably, CR of IP after DSA ending in submergence and ending in drying was 6.89% and 4.23%, respectively. In addition, ROC after 14-day DSA was enhanced to twice of that after CS. Results from scanning electronic microscope suggested that 14-day DSA induced thinner sheets with finer particles in IP compared to that after CS. Results from X-ray diffraction revealed that IP contained higher proportions of goethite, lepidocrocite, magnetite, and hematite after DSA than those after CS. Variable charge and surface area of IP after DSA were only 26.5% and 32.0% of those after CS, respectively. Together, our results indicated that proper strength DSA promoted ROC and transformation from AI to CI, and consequently increased CR of IP, while it changed its surface properties.
Показать больше [+] Меньше [-]Frog (Pelophylax bergeri, Günther 1986) endocrine disruption assessment: characterization and role of skin poly(ADP-ribose) polymerases Полный текст
2018
Guerriero, Giulia | Brundo, Maria Violetta | Labar, Sofiane | Bianchi, Anna Rita | Trocchia, Samantha | Rabbito, Dea | Palumbo, Giancarlo | Abdel-Gawad, Fagr Kh | De Maio, Anna
Model of the our research was the adult male amphibian anura, Pelophylax bergeri, poikilotherm species not considered threatened by the IUCN, sampled in representative sites at different degree. In the first phase, a biochemical characterization of the ADP-ribosylation on the skin of barcoded amphibian anura collected from Matese Lake (clean reference site in CE, Italy) was carried out. Two PARP isoforms were evidence: the first of 66 kDa is localized into nucleus and activated by DNA damage; the second of 150 kDa is in cytoplasm, as demonstrated by biochemical and immunohistochemical analysis. Subsequently, the PARP activity, the quantitative expression of androgen receptor gene, and the levels of arsenic and chromium in skin and testis of frog and soil, water, and sediment collected from sites at different degrees of pollution were measured. A significant variation of PARP activity and androgen receptor expression levels was detected in both tissues of barcoded frogs from Sarno and Scafati, along Sarno River (SA, Italy), suggesting that a PARP activation is correlated to pollution and to steroid-regulated physiology disruption.
Показать больше [+] Меньше [-]CO2 bio-fixation and biofuel production in an airlift photobioreactor by an isolated strain of microalgae Coelastrum sp. SM under high CO2 concentrations Полный текст
2018
Mousavi, Shokouh | Najafpour, Ghasem D. | Mohammadi, Maedeh
Microalgae cultivation is a promising approach to remove ambient CO₂ via photosynthesis process. This paper investigates the impact of high CO₂ concentrations (6, 12, and 16%) on algae growth, CO₂ biofixation, lipid and carbohydrate contents, and nutrient removal of newly isolated microalgae, Coelastrum sp. SM. In addition, the ability of microalgae to produce biodiesel at optimal condition was studied. The microalgae were cultivated in wastewater using an airlift photobioreactor. Under 12% CO₂, the maximum biomass productivity and CO₂ fixation rate were 0.267 g L⁻¹ day⁻¹ and 0.302 g L⁻¹ h⁻¹, respectively. Total Kjeldahl nitrogen (TKN), total phosphorous (TP), nitrate, and sCOD removal efficiency were 84.01, 100, 86.811, and 73.084%, respectively. Under 12% CO₂ and at the same condition for cell growth, the highest lipid and carbohydrate contents were 3 7.91 and 58.45%, respectively. The composition of fatty acids methyl ester (FAME) of the microalga lipid was defined. Based on the obtained results and FAME profile, Coelastrum sp. SM was a suitable feedstock for biodiesel production and also, the organism had a great potential for CO₂ biofixation, which is also more suitable than any other reported strains in other related studies.
Показать больше [+] Меньше [-]Change detection for Lake Burullus, Egypt using remote sensing and GIS approaches Полный текст
2018
Mohsen, A. | Elshemy, M. | Zeidan, B. A.
Lake Burullus is the second largest natural coastal lake in Egypt. It has an economic importance for fish yield. However, several anthropogenic activities such as industrial, agriculture, and reclamation activities lead to a deterioration of its water quality and a decrease of the water body area of the lake. This study aims to detect the spatiotemporal changes of Lake Burullus in the period 1972–2015 using 12 Landsat {(1,3-MSS), (4,5-TM), and (7-ETM+)} imageries and water indices approach. To extract water feature from imageries, the Normalized Difference Water Index (NDWI) and the Water Ratio Index (WRI) were applied. The NDWI was applied to the MSS imageries. For other TM and ETM+ imageries, the WRI was applied. Obtained results show a significant decrease in the water area of the Lake Burullus, where it lost about (49%) of its surface area during the period from the year 1972 to the year 2015. A rapid decrease in the lake surface area was noticed through the period from 1972 to 1984. A prediction model was built depending on the calculated water area of the lake. Finally, the multi-temporal maps of the lake surface area are overlaid to produce a map for the changes of the lake surface area using Geographic Information System (GIS).
Показать больше [+] Меньше [-]Concentration effects of the UV filter oxybenzone in Cyperus alternifolius: assessment of tolerance by stress-related response Полный текст
2018
Chen, Feiran | Schnick, Sandrine | Schröder, Peter
Phytoremediation has been proposed to reduce the load of the sunscreen oxybenzone (OBZ) in the aquatic environment. Despite the proven removal efficiency of this compound, little is known about its influence, particularly oxidative stress on plants. In this study, a short-term incubation of macrophytic Cyperus alternifolius was performed to prove the plant’s ability to withstand the stress. Detached shoots were immersed in medium spiked with different concentrations of OBZ (50, 100, and 500 μM) for 2, 4, and 7 days, respectively. Increased formation of O₂⁻ and H₂O₂ in Cyperus treated with OBZ was characterized by intense colorization following histochemical staining. Alterations of enzyme activities involved in the antioxidative defense system indicate an adaptive response of C. alternifolius to this xenobiotic stress. Quantification of lipid peroxidation reveals that no significant membrane damage occurred during incubation with OBZ. Overall, 50 μM OBZ (tenfold higher than the amount frequently detected in the environment) exhibited low toxic effects. Accordingly, this pilot study provides information on the potential use of Cyperus to remove emerging sunscreen contaminants from water bodies.
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