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Результаты 1671-1680 из 1,955
Acidic pharmaceuticals in domestic wastewater and receiving water from hyper-urbanization city of China (Shanghai): environmental release and ecological risk Полный текст
2013
Duan, Yan-Ping | Meng, Xiang-Zhou | Wen, Zhi-Hao | Chen, Ling
The occurrence, behavior, and release of five acidic pharmaceuticals, including ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA), have been investigated along the different units in a tertiary-level domestic wastewater treatment plant (WWTP) in hyper-urbanization city of China (Shanghai). IBP was the most abundant chemicals among the measured in raw wastewater. The loads of the acidic pharmaceuticals in the WWTP influent ranged from 7.5 to 414 mg/day/1,000 inh, which were lower than those reported in the developed countries suggesting a less per capita consumption of pharmaceuticals in Shanghai. IBP obtained by highest removal (87 %); NPX and KEP were also significantly removed (69–76 %). However, DFC and CA were only moderately removed by 37–53 %, respectively. Biodegradation seemed to play a key role in the elimination of the studied pharmaceuticals except for DFC and CA. An annual release of acidic pharmaceuticals was estimated at 1,499 and 61.7 kg/year through wastewater and sludge, respectively, from Shanghai. Highest pharmaceuticals concentrations were detected in the effluent discharge point of the WWTP, indicating that WWTP effluent is the main source of the acidic pharmaceuticals to its receiving river. Preliminary results indicated that only DFC in river had a high risk to aquatic organisms. Nevertheless, the joint toxicity effects of these chemicals are needed to further investigate.
Показать больше [+] Меньше [-]Assessing the impact of organic and inorganic amendments on the toxicity and bioavailability of a metal-contaminated soil to the earthworm Eisenia andrei Полный текст
2013
González, Verónica | Díez-Ortiz, María | Simón, Mariano | Gestel, Cornelis A. M. van
Metal-contaminated soil, from the El Arteal mining district (SE Spain), was remediated with organic (6 % compost) and inorganic amendments (8 % marble sludge) to reduce the mobility of metals and to modify its potential environmental impact. Different measures of metal bioavailability (chemical analysis; survival, growth, reproduction and bioaccumulation in the earthworm Eisenia andrei), were tested in order to evaluate the efficacy of organic and inorganic amendments as immobilizing agents in reducing metal (bio)availability in the contaminated soil. The inorganic amendment reduced water and CaCl2-extractable concentrations of Cd, Pb, and Zn, while the organic amendment increased these concentrations compared to the untreated soil. The inorganic treatment did not significantly reduce toxicity for the earthworm E. andrei after 28 days exposure. The organic amendment however, made the metal-contaminated soil more toxic to the earthworms, with all earthworms dying in undiluted soil and completely inhibiting reproduction at concentrations higher than 25 %. This may be due to increased available metal concentrations and higher electrical conductivity in the compost-amended soil. No effects of organic and inorganic treatments on metal bioaccumulation in the earthworms were found and metal concentrations in the earthworms increased with increasing total soil concentrations.
Показать больше [+] Меньше [-]Effects of silicon and copper on bamboo grown hydroponically Полный текст
2013
Collin, Blanche | Doelsch, Emmanuel | Keller, Catherine | Panfili, Frédéric | Meunier, Jean-Dominique
Effects of silicon and copper on bamboo grown hydroponically Полный текст
2013
Collin, Blanche | Doelsch, Emmanuel | Keller, Catherine | Panfili, Frédéric | Meunier, Jean-Dominique
Due to its high growth rate and biomass production, bamboo has recently been proven to be useful in wastewater treatment. Bamboo accumulates high silicon (Si) levels in its tissues, which may improve its development and tolerance to metal toxicity. This study investigates the effect of Si supplementation on bamboo growth and copper (Cu) sensitivity. An 8-month hydroponic culture of bamboo Gigantocloa sp. "Malay Dwarf " was performed. The bamboo plants were first submitted to a range of Si supplementation (0-1.5 mM). After 6 months, a potentially toxic Cu concentration of 1.5 μM Cu(2+) was added. Contrary to many studies on other plants, bamboo growth did not depend on Si levels even though it absorbed Si up to 218 mg g(-1) in leaves. The absorption of Cu by bamboo plants was not altered by the Si supplementation; Cu accumulated mainly in roots (131 mg kg(-1)), but was also found in leaves (16.6 mg kg(-1)) and stems (9.8 mg kg(-1)). Copper addition did not induce any toxicity symptoms. The different Cu and Si absorption mechanisms may partially explain why Si did not influence Cu repartition and concentration in bamboo. Given the high biomass and its absorption capacity, bamboo could potentially tolerate and accumulate high Cu concentrations making this plant useful for wastewater treatment.
Показать больше [+] Меньше [-]Effects of silicon and copper on bamboo grown hydroponically Полный текст
2013
Collin B. | Doelsch E. | Keller C. | Panfili F. | Meunier J.D.
Due to its high growth rate and biomass production, bamboo has recently been proven to be useful in wastewater treatment. Bamboo accumulates high silicon (Si) levels in its tissues, which may improve its development and tolerance to metal toxicity. This study investigates the effect of Si supplementation on bamboo growth and copper (Cu) sensitivity. An 8-month hydroponic culture of bamboo Gigantocloa sp. "Malay Dwarf " was performed. The bamboo plants were first submitted to a range of Si supplementation (0-1.5 mM). After 6 months, a potentially toxic Cu concentration of 1.5 ?M Cu2+ was added. Contrary to many studies on other plants, bamboo growth did not depend on Si levels even though it absorbed Si up to 218 mg g?1 in leaves. The absorption of Cu by bamboo plants was not altered by the Si supplementation; Cu accumulated mainly in roots (131 mg kg?1), but was also found in leaves (16.6 mg kg?1) and stems (9.8 mg kg?1). Copper addition did not induce any toxicity symptoms. The different Cu and Si absorption mechanisms may partially explain why Si did not influence Cu repartition and concentration in bamboo. Given the high biomass and its absorption capacity, bamboo could potentially tolerate and accumulate high Cu concentrations making this plant useful for wastewater treatment. (Résumé d'auteur)
Показать больше [+] Меньше [-]Photodegradation of sulfonamides and their N 4-acetylated metabolites in water by simulated sunlight irradiation: kinetics and identification of photoproducts Полный текст
2013
Periša, Martina | Babić, Sandra | Škorić, Irena | Frömel, Tobias | Knepper, T. P. (Thomas P.)
Once released into the aquatic environment, pharmaceuticals may undergo different degradation processes. Photodegradation, for example, might be an important elimination process for light-sensitive pharmaceuticals, such as antibiotics. In this study, the fate of sulfonamides (sulfamethazine, sulfadiazine, and sulfamethoxazole) and their N⁴-acetylated metabolites (N⁴-acetylsulfadiazine, N⁴-acetylsulfamethazine, and N⁴-acetylsulfamethoxazole) under simulated sunlight irradiation was investigated. The irradiation resulted in total or almost total degradation (88 to 98 %) of the pharmaceuticals tested, except for sulfamethazine (52 %), during 24 h of irradiation. The photoproducts of all investigated pharmaceuticals have been analyzed using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. Structure elucidation performed from photodegradation products of both, sulfonamides and their N⁴-acetylated metabolites, clearly showed two major formation pathways. These were cleavage of the sulfonamide bond as well as SO₂extrusion. In total, nine photoproducts were elucidated. Among these photoproducts, the tautomers of sulfamethoxazole and desulfonated products of sulfadiazine and sulfamethazine were also present. Tautomers of sulfadiazine and sulfamethazine have been characterized here for the first time as well as some photoproducts of sulfadiazine, sulfametoxazole, and their metabolites N⁴-acetylsulfadiazine and N⁴-acetylsulfametoxazole. The obtained results are an important piece in the complex puzzle for assessing the environmental fate of sulfonamides and their metabolites in the environment.
Показать больше [+] Меньше [-]A simple method to prepare magnetic modified beer yeast and its application for cationic dye adsorption Полный текст
2013
Yu, Jun-Xia | Wang, Li-Yan | Chi, Ru-An | Zhang, Yue-Fei | Xu, Zhi-Gao | Guo, Jia
The purpose of this research is to use a simple method to prepare magnetic modified biomass with good adsorption performances for cationic ions. The magnetic modified biomass was prepared by two steps: (1) preparation of pyromellitic dianhydride (PMDA) modified biomass in N, N-dimethylacetamide solution and (2) preparation of magnetic PMDA modified biomass by a situ co-precipitation method under the assistance of ultrasound irradiation in ammonia water. The adsorption potential of the as-prepared magnetic modified biomass was analyzed by using cationic dyes: methylene blue and basic magenta as model dyes. Optical micrograph and x-ray diffraction analyses showed that Fe₃O₄ particles were precipitated on the modified biomass surface. The as-prepared biosorbent could be recycled easily by using an applied magnetic field. Titration analysis showed that the total concentration of the functional groups on the magnetic PMDA modified biomass was calculated to be 0.75 mmol g⁻¹ by using the first derivative method. The adsorption capacities (q ₘ) of the magnetic PMDA modified biomass for methylene blue and basic magenta were 609.0 and 520.9 mg g⁻¹, respectively, according to the Langmuir equation. Kinetics experiment showed that adsorption could be completed within 150 min for both dyes. The desorption experiment showed that the magnetic sorbent could be used repeatedly after regeneration. The as-prepared magnetic modified sorbent had a potential in the dyeing industry wastewater treatment.
Показать больше [+] Меньше [-]Observation of carbonaceous aerosols during 2006–2009 in Nyainqêntanglha Mountains and the implications for glaciers Полный текст
2013
Zhao, Shuyu | Ming, Jing | Sun, Junying | Xiao, Cunde
Atmospheric carbonaceous aerosols were sampled discontinuously from July 2006 to December 2009 at Nam Co Comprehensive Observation and Research Station (NCOS) in the central Tibetan Plateau (TP). The mean daily concentration of carbonaceous aerosols increased from 268 to 330 ng m(-3), and pollution episodes could significantly increase the mean level of carbonaceous aerosols in the total mass concentration. Organic carbon was the main component of carbonaceous aerosols at NCOS, and black carbon (BC) accounted for 5.8 %. Seven-day air masses backward trajectories calculated by the Hybrid Single-Particle Lagrangian Integrated Trajectory model and the aerosol optical depth distribution in the TP and South Asia both suggested that atmospheric pollutants emitted from Northern India and South Asia could penetrate into central TP by southwest winds. Due to the seasonal variations of emission sources and regional atmospheric conditions, calculated BC deposition flux in the nonmonsoon season was higher than that in the monsoon season. Increased BC concentration in snowpack in winter from 2007 to 2009 indicated that the atmospheric environment in central TP became more polluted and the influences from human activities have strengthened. Pollution episodes could significantly increase BC concentrations in the snowpack on a seasonal scale, which would furthermore affect the surface albedo.
Показать больше [+] Меньше [-]Arsenic contamination in the freshwater fish ponds of Pearl River Delta: bioaccumulation and health risk assessment Полный текст
2013
Cheng, Zhang | Chen, Kun-Ci | Li, Kai-Bin | Nie, Xiang-Ping | Wu, Sheng Chun | Wong, Chris Kong-Chu | Wong, Ming-Hung
This study investigated the extent of arsenic (As) contamination in five common species of freshwater fish (northern snakehead [Channa argus], mandrarin fish [Siniperca chuatsi], largemouth bass [Lepomis macrochirous], bighead carp [Aristichthys nobilis] and grass carp [Ctenopharyngodon idellus]) and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The total As concentrations detected in fish muscle and sediment in freshwater ponds around the PRD were 0.05–3.01 mg kg⁻¹wet weight (w. wt) and 8.41–22.76 mg kg⁻¹dry weight (d. wt), respectively. In addition, the As content was positively correlated (p < 0.05) to total organic carbon (TOC) contents in sediments. Biota sediment accumulation factor (BSAF) showed that omnivorous fish and zooplankton accumulated higher concentrations of heavy metals from the sediment than carnivorous fish. In addition, feeding habits of fish also influence As accumulation in different fish species. In this study, two typical food chains of the aquaculture ponds were selected for investigation: (1) omnivorous food chain (zooplankton, grass carp and bighead carp) and (2) predatory food chain (zooplankton, mud carp and mandarin fish). Significant linear relationships were obtained between log As and δ¹⁵N. The slope of the regression (−0.066 and −0.078) of the log transformed As concentrations and δ¹⁵N values, as biomagnifications power, indicated there was no magnification or diminution of As from lower trophic levels (zooplankton) to fish in the aquaculture ponds. Consumption of largemouth bass, northern snakehead and bighead carp might impose health risks of Hong Kong residents consuming these fish to the local population, due to the fact that its cancer risk (CR) value exceeded the upper limit of the acceptable risk levels (10⁻⁴) stipulated by the USEPA.
Показать больше [+] Меньше [-]Understanding the patterns and mechanisms of urban water ecosystem degradation: phytoplankton community structure and water quality in the Qinhuai River, Nanjing City, China Полный текст
2013
Zhao, Zhenhua | Mi, Tengfei | Xia, Liling | Yan, Wenming | Jiang, Ying | Gao, Yanzheng
The temporal and spatial distribution characteristics of environmental parameters and the phytoplankton community were investigated in October 2010 and January 2011 in the Qinhuai River, Nanjing, China. Results showed that the water quality in the study area was generally poor, and the main parameters exceeding standards (level V) were nitrogen and phosphorus. The observed average concentrations of the total nitrogen (TN) were 4.90 mg L⁻¹in autumn and 9.29 mg L⁻¹in winter, and those of the total phosphorus (TP) were 0.24 mg L⁻¹in autumn and 0.88 mg L⁻¹in winter, respectively. Thirty-seven species, 30 genera, and four phyla of phytoplankton were detected in the river. Cyanophyta and Bacillariophyta were the dominant phyla in autumn, with average abundance and biomass of 221.5 × 10⁴ cells L⁻¹and 4.41 mg L⁻¹, respectively. The dominant population in winter was Bacillariophyta, and the average abundance and biomass were 153.4 × 10⁴ cells L⁻¹and 6.58 mg L⁻¹, respectively. The results of canonical correspondence analysis (CCA) between environmental parameters and phytoplankton communities showed that Chlorophyta could tolerate the higher concentrations of the permanganate index, nitrogen, and phosphorus in eutrophic water; Bacillariophyta could adapt well to changing water environments; and the TN/TP ratio had obvious impacts on the distributions of Cyanophyta, Euglenophyta, and some species of Chlorophyta. CCA analyses for autumn and winter data revealed that the main environmental parameters influencing phytoplankton distribution were water temperature, conductivity, and total nitrogen, and the secondary factors were dissolved oxygen, NH₄⁺–N, NO₃–N, TN, CODMₙ, TN/TP ratio, and oxidation-reduction potential.
Показать больше [+] Меньше [-]Effects of lead and cadmium exposure from electronic waste on child physical growth Полный текст
2013
Yang, Hui | Huo, Xia | Yekeen, Taofeek Akangbe | Zheng, Qiujian | Zheng, Minghao | Xu, Xijin
Many studies indicate that lead (Pb) and cadmium (Cd) exposure may alter bone development through both direct and indirect mechanisms, increasing the risk of osteoporosis later in life. The aim of this study was to investigate the association between Pb and Cd exposure, physical growth, and bone and calcium metabolism in children of an electronic waste (e-waste) processing area. We recruited 246 children (3–8 years) in a kindergarten located in Guiyu, China. Blood lead levels (BLLs) and blood cadmium levels (BCLs) of recruited children were measured as biomarkers for exposure. Serum calcium, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline were used as biomarkers for bone and calcium metabolism. Physical indexes such as height, weight, and head and chest circumference were also measured. The mean values of BLLs and BCLs obtained were 7.30 μg/dL and 0.69 μg/L, respectively. The average of BCLs increased with age. In multiple linear regression analysis, BLLs were negatively correlated with both height and weight, and positively correlated with bone resorption biomarkers. Neither bone nor calcium metabolic biomarkers showed significant correlation with cadmium. Childhood lead exposure affected both physical development and increased bone resorption of children in Guiyu. Primitive e-waste recycling may threaten the health of children with elevated BLL which may eventually cause adult osteoporosis.
Показать больше [+] Меньше [-]Electrocoagulation-integrated hybrid membrane processes for the treatment of tannery wastewater Полный текст
2013
Keerthi, | Vinduja, V. | Balasubramanian, N.
Three different combinations of treatment techniques, i.e. electrocoagulation combined with microfiltration (EMR), membrane bioreactor (MBR) and electrocoagulation integrated with membrane bioreactor (hybrid MBR, (HMBR)), were analysed and compared for the treatment of tannery wastewater operated for 7 days under the constant trans-membrane pressure of 5 kPa. HMBR was found to be most suitable in performance as well as fouling reduction, with 94 % of chemical oxygen demand (COD) removal, 100 % chromium removal and 8 % improvement in percentage reduction in permeate flux compared to MBR with only 90 % COD removal and 67 % chromium removal. The effect of mixed liquor suspended solids on fouling was also investigated and was found to be insignificant. EMR was capable of elevating the flux but was not as efficient as HMBR and MBR in COD removal. Fouling reduction by HMBR was further confirmed by SEM-EDX and particle size analysis.
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