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891.
892.
Benn TM Westerhoff P Herckes P 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1334-1342
Detection methods are necessary to quantify fullerenes in commercial applications to provide potential exposure levels for future risk assessments of fullerene technologies. The fullerene concentrations of five cosmetic products were evaluated using liquid chromatography with mass spectrometry to separate and specifically detect C60 and C70 from interfering cosmetic substances (e.g., castor oil). A cosmetic formulation was characterized with transmission electron microscopy, which confirmed that polyvinylpyrrolidone encapsulated C60. Liquid-liquid extraction of fullerenes from control samples approached 100% while solid-phase and sonication in toluene extractions yielded recoveries of 27-42%. C60 was detected in four commercial cosmetics ranging from 0.04 to 1.1 μg/g, and C70 was qualitatively detected in two samples. A single-use quantity of cosmetic (0.5 g) may contain up to 0.6 μg of C60, demonstrating a pathway for human exposure. Steady-state modeling of fullerene adsorption to biosolids is used to discuss potential environmental releases from wastewater treatment systems. 相似文献
893.
Shannon L. Bartelt-Hunt Daniel D. Snow Johnette Shockley 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):786-791
The occurrence and estimated concentration of twenty illicit and therapeutic pharmaceuticals and metabolites in surface waters influenced by wastewater treatment plant (WWTP) discharge and in wastewater effluents in Nebraska were determined using Polar Organic Chemical Integrative Samplers (POCIS). Samplers were installed in rivers upstream and downstream of treated WWTP discharge at four sites and in a discharge canal at a fifth location. Based on differences in estimated concentrations determined from pharmaceuticals recovered from POCIS, WWTP effluent was found to be a significant source of pharmaceutical loading to the receiving waters. Effluents from WWTPs with trickling filters or trickling filters in parallel with activated sludge resulted in the highest observed in-stream pharmaceutical concentrations. Azithromycin, caffeine, 1,7-dimethylzanthine, carbamazepine, cotinine, DEET, diphenhydramine, and sulfamethazine were detected at all locations. Methamphetamine, an illicit pharmaceutical, was detected at all but one of the sampling locations, representing only the second report of methamphetamine detected in WWTP effluent and in streams impacted by WWTP effluent. 相似文献
894.
Marco Iotti Paola Fabbri Massimo Messori Francesco Pilati Patrizia Fava 《Journal of Polymers and the Environment》2009,17(1):10-19
Organic–inorganic hybrid coatings based on poly(ε-caprolactone), poly(ethylene oxide) or poly(lactic acid) as organic phase
and silica from tetraethoxysilane as inorganic phase were prepared by the sol–gel approach. Coatings were applied onto poly(lactic
acid) films for food packaging in order to improve its barrier properties towards oxygen and water vapour. All the prepared
coatings were dense, homogeneous layers characterized by a good adhesion to the substrate. The permeance of the coating layers
resulted one order of magnitude lower than that of the uncoated poly(lactic acid) (PLA) film. The hydrophilic character of
the coating did not permit to gain a significant decrease in the water vapour permeance. The perfect visual transparency of
the coatings allows their application without worsening of the esthetical properties of the substrate PLA film. 相似文献
895.
This paper presents the results of the monitoring programme on the urines of people living in an area of Central Italy (near the Republic of S. Marino) to evaluate the background level of the 210Po excretion rate (mBq day−1) in this region. The volunteers were subdivided in five age classes and in every age class groups of males and females, cigarette smokers and non-smokers were taken into account. The results indicated that the 210Po excretion rate was widely distributed within each group of volunteers. The 210Po excretion rate was <30 mBq day−1 for 93.2% of people. The obtained results are discussed and some conclusion, based upon the average values, was drawn. 相似文献
896.
A study was performed to determine the potential of two-liquid-phase (TLP) bioslurry reactors using silicon oil as solvent for degradation of residual contaminants in petroleum-contaminated soil. The residues were characterized by gas chromatography–mass spectrometry and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. This allowed for the identification of a mixture of residual biomarkers, metabolic byproducts, oxygenated and hetero-polynuclear aromatic hydrocarbons in the contaminated soil. The removal amount of total extractable organics (TEO) was 15 900 mg kg−1 soil in the TLP reactor within 12 weeks. However, TEO remained intact in the bioslurry reactor without the addition of silicon oil for the duration of the experiment, due to high toxicity of metabolites to the microorganisms. The availability of TEO was calculated using a mild extraction with Triton X-100, and the amount of TEO extracted was in accord with the amount of biodegraded TEO. Significantly reduced toxicity in soil was observed at week 12 through TLP remediation. Dehydrogenase activity in the bioslurry reactor was strongly suppressed. Fluorescein diacetate was significantly hydrolyzed by the composition of bioremediation residues in the contaminated soil. Microbial adhesion to the solvent was revealed by the determination of microbial activity in the water-immiscible-liquid. 相似文献
897.
Fernando Goi Raul Lpez Arsenio Etxeandia Esmeralda Milln Asuncin Vives Pilar Amiano 《Chemosphere》2009,76(11):1533-1539
A gel permeation chromatographic (GPC) clean-up based method was developed for determination of selected organochlorine pesticides and polychlorinated biphenyls in human serum. The method permits automation of the sample extract clean-up stage and is designed to work with small amounts of sample. Different working variables were studied in its development, including injection volume, flow rate, and fat amount as the most representative coextract. The method provides solvent and time savings. Initial extraction was performed using 96-well solid-phase disk extraction plates, and quantification was performed by gas chromatography with electron capture detection and mass spectrometry. Recoveries of PCB congeners 28, 52, 101, 118, 138, 153, and 180 and organochlorine pesticides HCB, β-HCH, γ-HCH, heptachlor epoxide, p,p′-DDE, and p,p′-DDT at two spiking levels ranged from 55% to 115% with relative standard deviations ranging from 2.0% to 14.6%. Limits of quantification ranged from 0.06 to 0.16 ng mL−1 for PCBs and from 0.12 to 0.36 ng mL−1 for organochlorine pesticides. Finally, the method was applied to the analysis of 38 serum samples and the results were compared with those of another procedure validated at the laboratory. 相似文献
898.
测定地表水及饮用水中硫酸盐的两种方法探讨 总被引:2,自引:0,他引:2
通过比较两种监测分析方法,分析了测定硫酸盐分光光度法的影响因素、存在问题,以及火焰原子吸收法的优点,提出对不同浓度范围的硫酸盐,宜采用合适的分析方法,以减小测定的误差,提高测定结果的准确性和科学性。 相似文献
899.
Isotopes of uranium in the sea-water sediments collected from two different areas (El Hamraween harbour and Ras El Behar) on the Egyptian coast of the red sea have been studied using radiochemical separation procedures and alpha-particle spectrometry. Activity concentrations of 238U, 235U, 234U were calculated. The activities observed indicated enhanced radioactivity levels in sea-water sediments of El Hamraween harbour area due to the activities of phosphate shipment operation. Secular equilibrium between 234U and 238U was found in the analyzed samples. The average activity ratio of 235U/238U was close to the value 0.046 for uranium in nature. 相似文献
900.
A submerged macrophyte of the Yenisei River, Elodea canadensis, was used to study the microdistribution of the artificial radionuclide 241Am among different components of the plant. The total amount of 241Am added to the experimental system was 1850 ± 31 Bq/L. The total amount of 241Am accumulated by the plants was 182 Bq per sample, or 758,333 ± 385 Bq/kg dry mass. It has been found that the major portion of 241Am accumulated by E. canadensis, up to 85%, was bound to solid components of the cells. It is observed that the microdistribution of 241Am within different components of the submerged plant E. canadensis was not uniform. 241Am distribution vary depending on the age of the leaf blades, the state of the cells and morphological features of the plant stem. 相似文献