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Результаты 1561-1570 из 1,955
Internalization of SiO2 nanoparticles by alveolar macrophages and lung epithelial cells and its modulation by the lung surfactant substitute Curosurf® Полный текст
2013
Vranic, Sandra | Garcia-Verdugo, Ignacio | Darnis, Cécile | Sallenave, Jean-Michel | Boggetto, Nicole | Marano, F. (Francelyne) | Boland, Sonja | Baeza-Squiban, Armelle
Because of an increasing exposure to environmental and occupational nanoparticles (NPs), the potential risk of these materials for human health should be better assessed. Since one of the main routes of entry of NPs is via the lungs, it is of paramount importance to further characterize their impact on the respiratory system. Here, we have studied the uptake of fluorescently labeled SiO₂ NPs (50 and 100 nm) by epithelial cells (NCI-H292) and alveolar macrophages (MHS) in the presence or absence of pulmonary surfactant. The quantification of NP uptake was performed by measuring cell-associated fluorescence using flow cytometry and spectrometric techniques in order to identify the most suitable methodology. Internalization was shown to be time and dose dependent, and differences in terms of uptake were noted between epithelial cells and macrophages. In the light of our observations, we conclude that flow cytometry is a more reliable technique for the study of NP internalization, and importantly, that the hydrophobic fraction of lung surfactant is critical for downregulating NP uptake in both cell types.
Показать больше [+] Меньше [-]Biosorption of arsenic from aqueous solution using dye waste Полный текст
2013
Nigam, Shubha | Vankar, Padma Shree | Gopal Krishna,
The purpose of this study is to examine on removal of arsenic from water by biosorption through potential application of herbal dye wastes. Four different flower dye residues (after extraction of natural dye) viz. Hibiscus rosasinensis, Rosa rosa, Tagetes erecta, and Canna indica were utilized successfully for the removal of arsenic from aqueous solution. Batch studies were carried out for various parameters viz. pH, sorbent dose, contact time, initial metal ion concentration, and temperature. Data were utilized for isothermal, kinetic, and thermodynamic studies. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDAX), and Fourier transform infrared (FTIR) analyses of biomass were performed. The results showed that 1 g/100 ml for 5.0–5.5 h contact time at pH 6.0–7.5 with agitation rate 150 rpm provided 98, 96, 92, and 85 % maximum absorption of arsenic by R. rosa, H. rosasinensis, T. erecta, and C. indica, respectively, at initial concentration of 500 ppb. Data followed Langmuir isotherm showing sorption to be monolayer on heterogeneous surface of biosorbent. Negative values of ΔG° indicated spontaneous nature, whereas ΔH° indicates exothermic nature of system followed by pseudo-first-order adsorption kinetics. FTIR results showed apparent changes in functional group regions after metal chelation. SEM and EDAX analyses showed the changes in surface morphology of all test biosorbents. Herbal dye wastes, used as biosorbent, exhibited significant (85–98 %) removal of arsenic from aqueous solution. Hence, these biosorbents are cost-effective, easily available, eco-friendly, and comparatively more effective than other biosorbents already in use. These may be used to remove arsenic and other toxic metals from water.
Показать больше [+] Меньше [-]Semi-specific Microbacterium phyllosphaerae-based microbial sensor for biochemical oxygen demand measurements in dairy wastewater Полный текст
2013
Kibena, Elo | Raud, Merlin | Jõgi, Eerik | Kikas, Timo
Although the long incubation time of biochemical oxygen demand (BOD₇) measurements has been addressed by the use of microbial biosensors, the resulting sensor-BOD values gained from the measurements with specific industrial wastewaters still underestimates the BOD value of such samples. This research aims to provide fast and more accurate BOD measurements in the dairy wastewater samples. Unlike municipal wastewater, wastewater from the dairy industry contains many substrates that are not easily accessible to a majority of microorganisms. Therefore, a bacterial culture, Microbacterium phyllosphaerae, isolated from dairy wastewater was used to construct a semi-specific microbial biosensor. A universal microbial biosensor based on Pseudomonas fluorescens, which has a wide substrate spectrum but is nonspecific to dairy wastewater, was used as a comparison. BOD biosensors were calibrated with OECD synthetic wastewater, and experiments with different synthetic and actual wastewater samples were carried out. Results show that the semi-specific M. phyllosphaerae-based microbial biosensor is more sensitive towards wastewaters that contain milk derivates and butter whey than the P. fluorescens-based biosensor. Although the M. phyllosphaerae biosensor underestimates the BOD₇ value of actual dairy wastewaters by 25–32 %, this bacterial culture is more suitable for BOD monitoring in dairy wastewater than P. fluorescens, which underestimated the same samples by 46–61 %.
Показать больше [+] Меньше [-]Lead accumulation and elimination in tissues of Prussian carp, Carassius gibelio (Bloch, 1782), after long-term dietary exposure, and depuration periods Полный текст
2013
Łuszczek-Trojnar, Ewa | Drąg-Kozak, Ewa | Popek, Wlodzimierz
Lead accumulation and elimination in tissues of Prussian carp, Carassius gibelio (Bloch, 1782), after long-term dietary exposure, and depuration periods Полный текст
2013
Łuszczek-Trojnar, Ewa | Drąg-Kozak, Ewa | Popek, Wlodzimierz
We studied the bioaccumulation of lead in selected tissues of Prussian carp Carassius gibelio (Bloch, 1782) during 12 and 24 months exposure to different doses of this metal in feed and the elimination of lead from tissues during the following 12-month depuration period. Lead concentration was determined using atomic absorption spectrometry method. The highest lead concentrations were observed at 2.0 ± 0.54 to 7.4 ± 1.1 mg kg⁻¹ in the kidney, 3.0 ± 0.13 to 5.2 ± 0.17 mg kg⁻¹ in the bone, and 4.5 (±0.4) mg kg⁻¹ in the hepatopancreas of fish from groups exposed to lead dietary concentration from 8 to 49 mg kg⁻¹ for 24 months. The rate of accumulation were generally the highest at the beginning of exposure as evidenced by the highest monthly increments of bioaccumulation observed after 3 months of contamination for muscles, hepatopancreatic gland, intestine, and gills. Also analysis of the monthly increments of lead bioaccumulation in bone tissue and the highly significant coefficients of correlation indicate that the dynamics of accumulation are clearly dependent on dose of exposure. Depuration of accumulated lead from the organs depended mainly on tissue and duration of elimination period. Very rapid depuration was observed in soft tissues such as the intestine or muscles. Very low elimination was observed for scales and bones where until the end of the experiment highly significant lead concentration differences were observed in all groups in relation to the control group. Chronic dietary exposure in the range of 8–49 mg Pb kg⁻¹ resulted in no significant effects on the growth and survival of Prussian carp females.
Показать больше [+] Меньше [-]Lead accumulation and elimination in tissues of Prussian carp, Carassius gibelio (Bloch, 1782), after long-term dietary exposure, and depuration periods Полный текст
Ewa Łuszczek-Trojnar | Ewa Drąg-Kozak | Włodzimierz Popek
We studied the bioaccumulation of lead in selected tissues of Prussian carp Carassius gibelio (Bloch, 1782) during 12 and 24 months exposure to different doses of this metal in feed and the elimination of lead from tissues during the following 12-month depuration period. Lead concentration was determined using atomic absorption spectrometry method. The highest lead concentrations were observed at 2.0 ± 0.54 to 7.4 ± 1.1 mg kg(-1) in the kidney, 3.0 ± 0.13 to 5.2 ± 0.17 mg kg(-1) in the bone, and 4.5 (±0.4) mg kg(-1) in the hepatopancreas of fish from groups exposed to lead dietary concentration from 8 to 49 mg kg(-1) for 24 months. The rate of accumulation were generally the highest at the beginning of exposure as evidenced by the highest monthly increments of bioaccumulation observed after 3 months of contamination for muscles, hepatopancreatic gland, intestine, and gills. Also analysis of the monthly increments of lead bioaccumulation in bone tissue and the highly significant coefficients of correlation indicate that the dynamics of accumulation are clearly dependent on dose of exposure. Depuration of accumulated lead from the organs depended mainly on tissue and duration of elimination period. Very rapid depuration was observed in soft tissues such as the intestine or muscles. Very low elimination was observed for scales and bones where until the end of the experiment highly significant lead concentration differences were observed in all groups in relation to the control group. Chronic dietary exposure in the range of 8-49 mg Pb kg(-1) resulted in no significant effects on the growth and survival of Prussian carp females. | Prussian carp, dietary, lead, exposure, accumulation, depuration | 30 | 3122-3132 | 20
Показать больше [+] Меньше [-]Chemical amendment of pig slurry: control of runoff related risks due to episodic rainfall events up to 48 h after application Полный текст
2013
O’ Flynn, Cornelius J. | Healy, Mark G. | Wilson, Paul | Hoekstra, Nyncke J. | Troy, Shane M. | Fenton, O. (Owen)
Losses of phosphorus (P) from soil and slurry during episodic rainfall events can contribute to eutrophication of surface water. However, chemical amendments have the potential to decrease P and suspended solids (SS) losses from land application of slurry. Current legislation attempts to avoid losses to a water body by prohibiting slurry spreading when heavy rainfall is forecast within 48 h. Therefore, in some climatic regions, slurry spreading opportunities may be limited. The current study examined the impact of three time intervals (TIs; 12, 24 and 48 h) between pig slurry application and simulated rainfall with an intensity of 11.0 ± 0.59 mm h-1. Intact grassed soil samples, 1 m long, 0.225 m wide and 0.05 m deep, were placed in runoff boxes and pig slurry or amended pig slurry was applied to the soil surface. The amendments examined were: (1) commercial-grade liquid alum (8 % Al2O3) applied at a rate of 0.88:1 [Al/ total phosphorus (TP)], (2) commercial-grade liquid ferric chloride (38 % FeCl3) applied at a rate of 0.89:1 [Fe/TP] and (3) commercial-grade liquid poly-aluminium chloride (10 % Al2O3) applied at a rate of 0.72:1 [Al/TP]. Results showed that an increased TI between slurry application and rainfall led to decreased P and SS losses in runoff, confirming that the prohibition of land-spreading slurry if heavy rain is forecast in the next 48 h is justified. Averaged over the three TIs, the addition of amendment reduced all types of P losses to concentrations significantly different (p < 0.05) to those from unamended slurry, with no significant difference between treatments. Losses from amended slurry with a TI of 12 h were less than from unamended slurry with a TI of 48 h, indicating that chemical amendment of slurry may be more effective at ameliorating P loss in runoff than current TI-based legislation. Due to the high cost of amendments, their incorporation into existing management practices can only be justified on a targeted basis where inherent soil characteristics deem their usage suitable to receive amended slurry. © 2013 Springer-Verlag Berlin Heidelberg.
Показать больше [+] Меньше [-]Olive tree, Olea europaea L., leaves as a bioindicator of atmospheric PCB contamination Полный текст
2013
Sofuoglu, Sait C. | Yayla, Burak | Kavcar, Pınar | Ates, Duygu | Turgut, Cafer | Sofuoglu, Aysun
Olive tree leaf samples were collected to investigate their possible use for biomonitoring of lipophilic toxic substances. The samples were analyzed for 28 polychlorinated biphenyls (PCB) congeners. Twelve congeners were detected in the samples. PCB-60, 77, 81, 89, 105, 114, and 153 were the most frequently detected congeners ranging from 32 % for PCB-52 to 97 % for PCB-81. Σ12PCBs concentration varied from below detection limit to 248 ng/g wet weight in the sampling area, while the mean congener concentrations ranged from 0.06 ng/g (PCB-128 + 167) to 64.2 ng/g wet weight (PCB-60). Constructed concentration maps showed that olive tree leaves can be employed for the estimation of spatial distrubution of these congeners.
Показать больше [+] Меньше [-]The acute effects of fine particles on respiratory mortality and morbidity in Beijing, 2004–2009 Полный текст
2013
Li, Pei | Xin, Jinyuan | Wang, Yuesi | Wang, Shigong | Li, Guoxing | Pan, Xiaochuan | Liu, Zirui | Wang, Lili
Recent epidemiological and toxicological studies have shown associations between particulate matter and human health. However, the estimates of adverse health effects are inconsistent across many countries and areas. The stratification and interaction models were employed within the context of the generalized additive Poisson regression equation to examine the acute effects of fine particles on respiratory health and to explore the possible joint modification of temperature, humidity, and season in Beijing, China, for the period 2004-2009. The results revealed that the respiratory health damage threshold of the PM2.5 concentration was mainly within the range of 20-60 μg/m(3), and the adverse effect of excessively high PM2.5 concentration maintained a stable level. In the most serious case, an increase of 10 μg/m(3) PM2.5 results in an elevation of 4.60 % (95 % CI 3.84-4.60 %) and 4.48 % (95 % CI 3.53-5.41 %) with a lag of 3 days, values far higher than the average level of 0.69 % (95 % CI 0.54-0.85 %) and 1.32 % (95 % CI 1.02-1.61 %) for respiratory mortality and morbidity, respectively. There were strong seasonal patterns of adverse effects with the seasonal variation of temperature and humidity. The growth rates of respiratory mortality and morbidity were highest in winter. And, they increased 1.4 and 1.8 times in winter, greater than in the full year as PM2.5 increased 10 μg/m(3).
Показать больше [+] Меньше [-]Perfluorinated compounds and organochlorine pesticides in soils around Huaihe River: a heavily contaminated watershed in Central China Полный текст
2013
Meng, Jing | Wang, Tieyu | Wang, Pei | Giesy, John P. | Lü, Yonglong
Perfluorinated compounds (PFCs) and organochlorine pesticides (OCPs) were analyzed in surface soils along the Huaihe River. Sixteen target PFCs and nine OCPs were quantified in soils from a region of intensive industrial and agricultural development. Concentrations of PFCs and OCPs ranged from less than the limit of detection (LOD) to 1.22 ng/g and 3.63 to 227 ng/g, respectively. Contamination by OCPs was more serious than that of PFCs, which was consistent with the fact that OCPs were widely used in agriculture of the district while there was no known production or application of PFCs in the study area. The predominant PFCs in soils were PFOA and PFOS with concentrations that ranged from <LOD to 0.20 ng/g and <LOD to 0.21 ng/g, respectively. Among the three groups of OCPs, average concentrations of HCHs, DDTs, and HCB were 4.7, 23.7, and 1.4 ng/g, respectively. Results of principal component analysis revealed relatively weak associations between concentrations of PFCs and those of OCPs, while concentrations of OCPs exhibited similar patterns of distributions. Among the mainstream and five tributaries, the highest concentrations of PFCs were observed along the Pihe River, while the highest concentrations of OCPs occurred along the Xifeihe River. In general, concentrations of PFCs were evenly distributed, while those of OCPs exhibited relatively greater spatial differences.
Показать больше [+] Меньше [-]Factors controlling benzo(a)pyrene concentration in aerosols in the urbanized coastal zone. A case study: Gdynia, Poland (Southern Baltic Sea) Полный текст
2013
Staniszewska, Marta | Graca, Bożena | Bełdowska, Magdalena | Saniewska, Dominika
Annual study on the benzo(a)pyrene (BaP) concentration in aerosols in the coastal zone of the Gulf of Gdansk (southern Baltic) has been performed at Gdynia station. Combustion processes, especially domestic heating of both local and regional origin, were identified as the main sources of benzo(a)pyrene in this area. Concentrations observed during the heating season (mean 2.18 ng m⁻³) were significantly higher than these recorded in the non-heating season (mean 0.05 ng m⁻³). High benzo(a)pyrene concentrations were associated with low temperature and high humidity. Whereas high levels of precipitation usually decreased the BaP concentration in aerosols. The concentration of this factor in the studied area depended also on the wind direction and air masses trajectories. During heating season, continental air masses (coming from S, SE, SW) seemed to increase benzo(a)pyrene concentration, while maritime air masses (from N, NE, NW) caused its decrease. The differences in the BaP concentration resulting from potentially different emission levels of this compound during working and non-working days were not clearly pronounced.
Показать больше [+] Меньше [-]Effects of hydroxyapatite addition on heavy metal volatility during tannery sludge incineration Полный текст
2013
Tang, Ping | Zhou, Yongchao | Xie, Zhengmiao
The effectiveness of hydroxyapatite (HAP) on volatilization reducing of heavy metals during incineration of tannery sludge was investigated. The tannery sludge was treated through doped with different content of HAP, and then incinerated in the tube furnace at the temperature of 600 °C and 900 °C. The results showed that the volatilization rates decreased by 10.19 % for Pb, 10.17 % for Zn, 7.40 % for Cu and 5.33 % for Cr at 600 °C when the HAP content was raised to 20 %. At 900 °C, the volatilization rates of Pb, Cr and Cu decreased by about 40.0 %, 24.0 % and 9.0 %, respectively, while volatilization of Zn can be considered nearly unchanged at around 5 %. The heavy metals can be stabilized effectively in the incineration after the pyromorphite-like minerals were formed in the sludge doped with HAP.
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