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Результаты 1261-1270 из 1,546
Effect directed analysis and mixture effects of estrogenic compounds in a sediment of the river Elbe Полный текст
2012
Schmitt, Sebastian | Reifferscheid, Georg | Claus, Evelyn | Schlüsener, Michael | Buchinger, Sebastian
INTRODUCTION: Endocrine disrupting chemicals (EDCs) are present in the environment and can have serious effects on humans and wildlife. For the establishment of environmental quality guidelines and regulation of EDCs, a better understanding and knowledge of the occurrence and the behavior of environmental EDCs is necessary. The aim of the present study was to comprehensively identify substances that are responsible for the estrogenic effect of an environmental sediment sample taken from the river Elbe/Germany. DISCUSSION: The estrogenic effect of the organic sediment extract was determined using the yeast–estrogen–screen (YES). The sample was fractionated by liquid chromatography (LC) for effect directed analysis. The composition of estrogen-active fractions was further investigated by gas chromatography–mass spectrometry and high-resolution LC–MS analysis. The composition of the environmental sample was rebuilt with pure compounds in order to assess the partition of estrogenic activity caused by the identified compounds. The organic sediment extract showed an estrogenic potential of 1.9 ± 0.4 ng/g ethinylestradiol equivalents in the sediment. The most prominent contaminants with an estrogenic potential were 17β-estradiol, estrone, and 4-iso-nonylphenols, but other xenoestrogens like bisphenol A and stigmasterol could be found as well. A rebuild of the sample was measured in the YES in order to investigate mixture effects. About 67 % of the observed estrogenic effect in the sediment extract could be explained by a mixture which contained all identified compounds. Chlorophene (o-benzyl-p-chlorophenol)—a widely used antiseptic that was also identified in the sediment extract—has xenoestrogenic properties in the YES that are in the range of other xenoestrogens like 4-n-nonylphenol. This is the first report on chlorophene acting as a xenoestrogen.
Показать больше [+] Меньше [-]Nervous system disruption and concomitant behavioral abnormality in early hatched pufferfish larvae exposed to heavy oil Полный текст
2012
Kawaguchi, Masahumi | Sugahara, Yuki | Watanabe, Tomoe | Irie, Kouta | Ishida, Minoru | Kurokawa, Daisuke | Kitamura, Shin-Ichi | Takata, Hiromi | Handoh, Itsuki C. | Nakayama, Kei | Murakami, Yasunori
BACKGROUND AND OBJECTIVE: Spills of heavy oil (HO) over the oceans have been proven to have an adverse effect on marine life. It has been hypothesized that exposure of early larvae of sinking eggs to HO leads largely to normal morphology, whereas abnormal organization of the developing neural scaffold is likely to be found. HO-induced disruption of the nervous system, which controls animal behavior, may in turn cause abnormalities in the swimming behavior of hatched larvae. To clarify the toxicological effects of HO, we performed exposure experiments and morphological and behavioral analyses in pufferfish (Takifugu rubripes) larvae. EXPERIMENTAL PROCEDURE: Fertilized eggs of pufferfish were exposed to 50 mg/L of HO for 8 days and transferred to fresh seawater before hatching. The hatched larvae were observed for their swimming behavior, morphological appearance, and construction of muscles and nervous system. RESULTS AND DISCUSSION: In HO-exposed larvae, we did not detect any anomaly of body morphology. However, they showed an abnormal swimming pattern and disorganized midbrain, a higher center controlling movement. Our results suggest that HO-exposed fishes suffer developmental disorder of the brain that triggers an abnormal swimming behavior and that HO may be selectively toxic to the brain and cause physical disability throughout the life span of these fishes.
Показать больше [+] Меньше [-]Harvesting of Chlorella sp. using hollow fiber ultrafiltration Полный текст
2012
Huang, Cui | Chen, Xiaolin | Liu, Tianzhong | Yang, Zhaohui | Xiao, Yong | Zeng, Guangming | Sun, Xiuxuan
INTRODUCTION: The suitability of the application of ultrafiltration (UF) to harvest Chlorella sp. from the culture medium was examined. We investigated the effects of two improved UF system, forward air–water flushing and backwash with permeate, on the concentration process. MATERIALS AND METHODS: Backwash with permeate was selected as an optimization of the improved UF system, which was more effective for permeate flux recovery. Moreover, the hollow fiber UF system by adding periodical backwash with permeate was examined for Chlorella sp. harvesting. RESULTS AND DISCUSSION: It was found that Chlorella sp. could be concentrated with high recovery in a lab-scale experiment. An overall algal biomass recovery of above 90% was achieved when the volume concentration factor was 10. For an original biomass of 1.3 ± 0.05 g/L, 1 min backwash followed by 20 min forward concentrating was more effective, which resulted in a recovery of 94% and a high average flux of 30.3 L/m2/h. In addition, the algal recovery was highly correlated to the volume concentration factor and the initial biomass. A high concentration factor or a high initial biomass resulted in a low biomass recovery.
Показать больше [+] Меньше [-]Volatile organic compounds and bioaerosols in the vicinity of a municipal waste organic fraction treatment plant. Human health risks Полный текст
2012
Vilavert, Lolita | Nadal, Martí | Figueras, María J. | Domingo, José L.
PURPOSE: The aim of this study was to analyze air concentrations of chemical and microbiological pollutants in the vicinity of an organic waste treatment plant, Ecoparc-2, located in Montcada i Reixac (Catalonia, Spain), as well as to determine the seasonal trends. The human health risks due to the presence of those agents were also assessed. METHODS: Air samples were collected at different distances and wind directions from the Ecoparc-2 in two campaigns (winter and summer of 2010). The levels of 19 volatile organic compounds (VOCs) were analyzed by GC-MS or HPLC-UV. In turn, the airborne amount of total bacteria, gram-negative bacteria, and fungi (including Aspergillus fumigatus) was also determined. RESULTS: Mean VOC concentrations were found to be 32.4 and 15.7 μg/m3 in winter and summer, respectively. Fungi at 25°C presented the highest geometric mean (1,126 and 863 cfu/m3 in winter and summer, respectively), while the concentrations of fungi at 37°C and total bacteria were also important in the hot season (332 and 250 cfu/m3, respectively). These results are in agreement with data obtained from the scientific literature. Anyhow, no significant differences were observed between both campaigns including those related to distances and wind directions. The current pollutant levels in the surrounding environment were also various orders of magnitude lower than those recently observed inside the facility. CONCLUSIONS: The human exposure to VOCs near the Ecoparc-2 was estimated to be low. Furthermore, the current environmental concentrations of those chemical and microbiological agents were clearly below threshold values recommended by regulatory organizations.
Показать больше [+] Меньше [-]Effect of Pb toxicity on leaf growth, antioxidant enzyme activities, and photosynthesis in cuttings and seedlings of Jatropha curcas L Полный текст
2012
Shu, Xiao | Yin, LiYan | Zhang, QuanFa | Wang, Weibo
BACKGROUND: Cuttings and seedlings of Jatropha curcas L. were exposed to different regimes of lead (Pb) stress as Pb(NO3)2 at 0 (CK), 0.5, 1, 2, 3, and 4 mM kg−1 soil. OBJECTIVES: The effect of Pb treatment on the root length, tolerance index, photosynthetic pigments, photosynthetic activity, lipid peroxidation, and antioxidant enzyme was studied in a greenhouse pot experiment. RESULTS: The results showed that root lengths and tolerance index decreased with increase of Pb concentration, but tolerance index of cuttings was always lower than those of the seedlings. For cuttings, Pb treatment had a stimulating effect on chlorophyll content, carotenoid content, and superoxide dismutase (SOD) activity at low concentration and an inhibitory effect at higher concentration. For seedlings, SOD activity increased with increasing Pb concentration. In both seedlings and cuttings, Pb caused inhibition of leaf growth and photosynthesis, and induced the membrane damage which was more obvious in the cuttings. In comparison with the control, the dynamic tendency of catalase and perxidase activities in the leaves of Pb-stressed plants all ascended, and then declined. DISCUSSION: The increase in enzyme activities demonstrated that seedlings were more tolerant to Pb stress than cuttings. These results also indicate that the antioxidant system may play an important role in eliminating or alleviating the toxicity of Pb in J. curcas seedlings and cuttings. The accumulation of Pb increased in a concentration-dependent manner; however, its translocation from root to shoot was low. The cuttings accumulated significantly higher Pb in roots than seedlings.
Показать больше [+] Меньше [-]Enhanced degradation of azo dye alizarin yellow R in a combined process of iron–carbon microelectrolysis and aerobic bio-contact oxidation Полный текст
2012
Liang, Bin | Yao, Qian | Cheng, Haoyi | Gao, Shuhong | Kong, Fanying | Cui, Dan | Guo, Yuqi | Ren, Nanqi | Wang, Aijie
PURPOSE: With the aim of enhanced degradation of azo dye alizarin yellow R (AY) and further removal of the low-strength recalcitrant matter (LsRM) of the secondary effluent as much as possible, our research focused on the combination of aerobic bio-contact oxidation (ABO) with iron/carbon microelectrolysis (ICME) process. MATERIALS AND METHODS: The combined ABO (with effective volume of 2.4 l) and ICME (with effectively volume of 0.4 l) process were studied with relatively short hydraulic retention time (HRT) of 4 or 6 h. RESULTS: At the HRT of 6 h with the reflux ratio of 1 and 2, the AY degradation efficiency in the final effluent was >96.5%, and the total organic carbon (TOC) removal efficiency were 69.86% and 79.44%, respectively. At the HRT of 4 h and the reflux ratio of 2, TOC removal efficiency and AY degradation efficiency were 73.94% and 94.89%, respectively. The ICME process obviously enhanced the total AY removal and the generated micromolecule acids and aldehydes then that wastewater backflow to the ABO where they were further biodegraded. CONCLUSION: The present research might provide the potential options for the advanced treatment azo dyes wastewater with short HRT and acceptable running costs.
Показать больше [+] Меньше [-]Source apportionment of ultrafine and fine particle concentrations in Brisbane, Australia Полный текст
2012
Friend, Adrian J. | Ayoko, G. A. (Godwin A.) | Jayaratne, E Rohan | Jamriska, Milan | Hopke, Philip K. | Morawska, L. (Lidia)
PURPOSE: To investigate the significance of sources around measurement sites, assist the development of control strategies for the important sources and mitigate the adverse effects of air pollution due to particle size. METHODS: In this study, sampling was conducted at two sites located in urban/industrial and residential areas situated at roadsides along the Brisbane Urban Corridor. Ultrafine and fine particle measurements obtained at the two sites in June–July 2002 were analysed by positive matrix factorization. RESULTS: Six sources were present, including local traffic, two traffic sources, biomass burning and two currently unidentified sources. Secondary particles had a significant impact at site 1, while nitrates, peak traffic hours and main roads located close to the source also affected the results for both sites. CONCLUSIONS: This significant traffic corridor exemplifies the type of sources present in heavily trafficked locations and future attempts to control pollution in this type of environment could focus on the sources that were identified.
Показать больше [+] Меньше [-]Coupling of solar-assisted advanced oxidative and biological treatment for degradation of agro-residue-based soda bleaching effluent Полный текст
2012
Dhir, Amit | Prakash, Nagaraja Tejo | Sud, Dhiraj
This study evaluates the effect of integrated solar-assisted advanced oxidation process (AOP) and biological treatment on the extent of degradation of effluents from chlorination (C) and first alkaline extraction (E1) stages of soda pulp bleaching in agro-residue-based pulp and paper mill. Biodegradation of the effluents was attempted in suspended mode using activated sludge from the functional pulp and paper industry effluent treatment plant acclimatized to effluents in question. The photocatalytic treatment was employed using zinc oxide (ZnO) in slurry mode for decontamination of effluents in a batch manner and the degradation was evaluated in terms of reduction in chemical oxygen demand. The biological treatment (24 h) of C and E1 effluent resulted in 30 and 57 % of degradation, respectively. Solar-induced AOP of C and E1 effluents resulted in 53 and 43 % degradation under optimized conditions (2.5 g L−1 ZnO at pH 8.0) after 6 h of exposure. For C effluent, a short duration of solar/ZnO (1 h) prior to biological treatment reduced the time required at biological step from 24 to 12 h for almost same extent (92 %) of degradation. However, sequential biological treatment (24 h) followed by solar/ZnO (2 h) resulted in 85.5 % degradation. In contrast, in the case of E1 effluent, sequential biological (24 h)–solar/ZnO (2 h) system effectively degrades effluent to 95.4 % as compared to 84.8 % degradation achieved in solar/ZnO (2 h)–biological treatment (24 h) system. In the present study, the sequencing of photocatalysis with the biological treatment is observably efficient and technically viable process for the complete mineralization of the effluents.
Показать больше [+] Меньше [-]Environmental distribution of PAHs in pine needles, soils, and sediments Полный текст
2012
Navarro-Ortega, Alícia | Ratola, Nuno | Hildebrandt, Alain | Alves, Arminda | Lacorte, Sílvia | Barceló, Damià
INTRODUCTION: The content of 16 polycyclic aromatic hydrocarbons (PAHs) was determined in 60 samples from three environmental matrices (soils, sediments, and pine needles) in an effort to assess their distribution on a river basin scale. METHODS: A sampling campaign was carried out in 2006, selecting urban, industrial, and agricultural sampling sites along the northeast of Spain. Techniques used included pressurized liquid extraction and solid–liquid ultrasonic extraction followed by gas chromatography-electron impact ionization mass spectrometry. RESULTS: The mean total PAHs concentrations were 290 < 613 < 1,628 ng/g (dry weight) in pine needles, soil, and sediments, respectively. There is a good correspondence between the total concentration of soils and pine needles, as opposed to the levels between sediments and pine needles. The high concentrations found in some Pinus halepensis samples may reflect a superior uptake potential of this species in comparison to the others studied. The three matrices present a very different PAH distribution pattern, with pine needles showing a predominance of the lighter (2-, 3-, and 4-ring) PAHs, whereas 5- and 6-ring PAHs are the most abundant in soils. Sediments display a more heterogeneous pattern, with contributions of all the PAHs but different distribution depending on the site, suggesting a wider range of input sources. Established PAH molecular ratios and principal component analysis were used to identify the origins and profiles of PAHs. While sediments showed a wide range attributed to historical inputs, soils and pine needles confirmed the compartmentalization of the PAHs, with lighter airborne PAHs accumulated in pine needles and heavier ones in soils. CONCLUSIONS: It can be suggested that the monitoring of several matrices is a strong tool to elucidate the contamination sources and accumulation patterns of PAHs. However, given the influence of the matrix type on this assessment, the information should be considered complementary, yet allowing a more comprehensive depiction of the area in question.
Показать больше [+] Меньше [-]Identification and characterization of the atmospheric emission of polychlorinated naphthalenes from electric arc furnaces Полный текст
2012
Liu, Guorui | Zheng, Minghui | Du, Bing | Nie, Zhiqiang | Zhang, Bing | Hu, Jicheng | Xiao, Ke
Electric arc furnaces (EAF) are well recognized as significant sources of dioxins. EAFs have also been speculated to be sources of polychlorinated naphthalenes (PCNs) due to the close correlation between dioxin and PCN formation. However, assessment on PCN emissions from EAFs has not been carried out. The primary aim of this preliminary study is to identify and characterize the atmospheric emission of PCNs from EAFs. In this preliminary study, stack gas samples from two typical EAFs with different scales (EAF-1, 160 t batch−1; and EAF-2, 60 t batch−1) were collected by automatic isokinetic sampling technique, and PCN congeners in samples were analyzed by isotope dilution high-resolution gas chromatography combined with high-resolution mass spectrometry method. Emission concentrations of PCNs were 458 and 1,099 ng m−3 for EAF-1 and EAF-2, respectively. The emission factors of PCNs to air were 21.6 and 30.1 ng toxic equivalent t−1 for EAF-1 and EAF-2, respectively, which suggested that EAF is an important source of PCN release. With regard to the characteristics of PCNs from EAFs, lower chlorinated homologues were dominant. The PCN congeners comprised of CN27/30, CN52/60, CN66/67, and CN73 were the most abundant congeners for tetra-, penta-, hexa-, and hepta-chlorinated homologues, respectively. EAFs were identified to be an important PCN source, and the obtained data are useful for developing a PCN inventory. The congener profiles of PCNs presented here might provide helpful information for identifying the specific sources of PCNs emitted from EAFs.
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