加压溶气生化气浮法降解生活污水中有机物

将加压曝气生物氧化技术与加压溶气气浮工艺相结合,开发了一种快速处理生活污水的加压溶气生化气浮反应器(PA-DAF),并考察了反应器的泥水分离效果及压力、水力停留时间(HRT)、气水比对其去除生活污水内有机物的影响。实验结果表明,在压力0.4 MPa,HRT 1.5 h(Q=1.0 L/min),气水比3∶1的条件下,生活污水COD去除率可稳定在90%左右。同时发现,NH3-N去除效果不理想,有待后续研究进行优化。     

Characterization of an urban landfill soil by using physicochemical analysis and solid phase microextraction (SPME)—GC/MS

We have aimed at characterizing top soil samples taken in-situ from five different locations of the unregulated dumping site in Eskişehir/Turkey for a period of six months. The study is the first attempt in the city and in Turkey, regarding particularly the SPME (Solid Phase Microextraction Technique) analysis method utilized. A comprehensive research has been conducted to produce critical soil data to be used for indicating current risks as well as the urgency of rehabilitating the site and establishing a sanitary landfill in the site. Conventional physicochemical analytical methods and SPME technique were used to analyze the samples. Physicochemical analyses were performed for determining the pH, total dried matter, volatile matter, total nitrogen, phosphorus, macro elements and heavy metals. Meteorological data were also recorded for the same period. SPSS.10.0 statistical program was used to determine the correlation between meteorological data and physicochemical analysis results. Mean values were used in the correlation analyses. These data indicated that the air temperature and precipitation have significant effects on soil characteristics. SPME, coupled with GC/MS, was used to identify eighty six volatile and semi-volatile organic compounds contained in soil samples. The samples were extracted by headspace SPME with heating (δHS-SPME). SPME analyses were conducted using a commercially available polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber having a film thickness of 65 μm (Supelco) as a capture medium. The experimentally optimized headspace sampling conditions were arranged (15 min. at 50^˚C) before a 30 min. sampling period.     

Ambient ultraviolet radiation induces protective responses in soybean but does not attenuate indirect defense

We investigated the effects of ambient ultraviolet (UV) radiation on (i) the performance and chemistry of soybean plants, (ii) the performance of Spodoptera frugiperda and (iii) the foraging behavior of the herbivore's natural enemy Cotesia marginiventris which exploits herbivore-induced plant volatiles (VOC) for host location. The accumulation of protective phenolics was faster in plants receiving ambient UV than in controls exposed to sun light lacking UV. Accordingly, isorhamnetin- and quercetin-based flavonoids were increased in UV exposed plants. No UV effects were found on the performance and feeding behavior of S. frugiperda. Herbivore-damaged plants emitted the same VOC when grown under ambient or attenuated UV for 5, 10 or 30 days. Consequently, C. marginiventris was attracted but did not discriminate between exposed and unexposed soybeans. In summary, ambient UV radiation affected soybean morphology and physiology but did not destabilize interactions between trophic levels.     

Estimation of nitrogen balance between the atmosphere and Lake Balaton and a semi natural grassland in Hungary

The paper summarises the results to determine the fluxes of different N-compounds within the atmosphere and an aquatic and a terrestrial ecosystems, in Hungary. In the exchange processes of N-compounds between atmosphere and various ecosystems the deposition dominates. The net deposition fluxes are -730, -1270 and -1530 mg Nm(-2)yr(-1) for water, grassland, and forest ecosystems, respectively. For water, the main source of nitrogen compounds is the wet deposition. Ammonia gas is close to the equilibrium between the water and the air. For grassland the dry flux of nitric acid and ammonia is also an important term beside the wet deposition. Dry deposition to terrestrial ecosystems is roughly two times higher than wet deposition. A total of 8-10% of the nitrates and NH(x) deposited to terrestrial ecosystems are re-emitted into the air in the form of nitrous oxide (N2O) greenhouse gas.     

Volatile pollutants emitted from selected liquid household products

BACKGROUND, AIM, AND SCOPE: To identify household products that may be potential sources of indoor air pollution, the chemical composition emitted from the products should be surveyed. Although this kind of survey has been conducted by certain research groups in Western Europe and the USA, there is still limited information in scientific literature. Moreover, chemical components and their proportions of household products are suspected to be different with different manufacturers. Consequently, the current study evaluated the emission composition for 42 liquid household products sold in Korea, focusing on five product classes (deodorizers, household cleaners, color removers, pesticides, and polishes). MATERIALS AND METHODS: The present study included two phase experiments. First, the chemical components and their proportions in household products were determined using a gas chromatograph and mass spectrometer system. For the 19 target compounds screened by the first phase of the experiment and other selection criteria, the second phase was done to identify their proportions in the purged-gas phase. RESULTS: The number of chemicals in the household products surveyed ranged from 9 to 113. Eight (product class of pesticides) to 17 (product class of cleaning products) compounds were detected in the purged-gas phase of each product class. Several compounds were identified in more than one product class. Six chemicals (acetone, ethanol, limonene, perchloroethylene (PCE), phenol, and 1-propanol) were identified in all five product classes. There were 13 analytes occurring with a frequency of more than 10% in the household products: limonene (76.2%), ethanol (71.4%), PCE (66.7%), phenol (40.5%), 1-propanol (35.7%), decane (33%), acetone (28.6%), toluene (19.0%), 2-butoxy ethanol (16.7%), o-xylene (16.7%), chlorobenzene (14.3%), ethylbenzene (11.9%), and hexane (11.9%). All of the 42 household products analyzed were found to contain one or more of the 19 compounds. DISCUSSION: The chemical composition varied broadly along with the product classes or product categories, and it was different from that reported in other studies abroad, although certain target chemicals were identified in both studies. This finding supports an assertion that chemical components emitted from household products may be different in different products and with different manufacturers. The chlorinated pollutants identified in the present study have not been reported to be components of cleaning products in papers published since the early 1990s. Limonene was identified as having the highest occurrence in the household products in the present study, although it was not detected in any of 67 household products sold in the U.S. CONCLUSIONS: The emission composition of selected household products was successfully examined by purge-and-trap analysis. Along with other exposure information such as use pattern of household products and the indoor climate, this composition data can be used to estimate personal exposure levels of building occupants. This exposure data can be employed to link environmental exposure to health risk. It is noteworthy that many liquid household products sold in Korea emitted several toxic aromatic and chlorinated organic compounds. Moreover, the current finding suggests that product types and manufacturers should be considered, when evaluating building occupants' exposure to chemical components emitted from household products. RECOMMENDATIONS AND PERSPECTIVES: The current findings can provide valuable information for the semiquantitative estimation of the population inhalation exposure to these compounds in indoor environments and for the selection of safer household products. However, although the chemical composition is known, the emissions of household products might include compounds formed during the use of the product or compounds not identified as ingredients by this study. Accordingly, further studies are required, and testing must be done to determine the actual composition being emitted. Similar to eco-labeling of shampoos, shower gels, and foam baths proposed by a previous study, eco-labeling of other household products is suggested.     

烟花爆竹用氧化剂的研究进展

在调查研究的基础上,分析、总结、研讨用于烟花爆竹的氧化剂的历史、现状及发展方向。分析和讨论氯酸盐类、高氯酸盐类、硝酸盐类以及金属氧化物等氧化剂的物化性质、燃爆性能及各自用于烟火剂的优缺点。研究指出:将不同类型的氧化剂复合使用,当选择的组分及搭配的比例合适时,不仅能使各种氧化剂充分发挥其优点,而且还将产生一些新的实际的性能。同时提出:复合氧化剂是配制燃放效果好、安全性能高、价格低廉的烟花爆竹氧化剂的发展方向。     

富勒烯的吸附性及其在大气挥发性有机物分析中的应用

富勒烯不含官能团,对挥发性有机物具有化学惰性,能在效地吸附ＶＯＣｓ,吸附ＶＯＣｓ气体后存放稳定,组分流失少,９种ｍｇ．ｌ＾－１级ＶＯＣｓ在富勒烯吸附管上的吸附突破体积为１４．８－４８．０Ｌ．ｇ＾－１,吸附－热脱附回收率在８６．５－１２３％之间。     

Altitudinal and thermal gradients of hepatic Cyp1A gene expression in natural populations of Salmo trutta from high mountain lakes and their correlation with organohalogen loads

The biomarker of xenobiotic exposure cytochrome p450A1 (Cyp1A) was used to analyze the biological response to chemical pollution in Salmo trutta (brown trout) from nine high mountain European lakes in Norway, Tatras, Tyrol, and central Pyrenees. Hepatic Cyp1A mRNA levels correlated both with the reciprocal of absolute annual average air temperatures of the sampled lakes and with muscle concentrations of several hydrophobic organohalogen compounds (OC), including chlorinated polychlorobiphenyls (PCB), DDE, and DDT. The correlation between Cyp1A expression and OC content was observed across the whole temperature range (between −0.7 °C and +6.2 °C), but also in the absence of any thermal gradient. We concluded that airborne pollutants accumulate in high mountain lake fish at concentrations high enough to increase Cyp1A expression, among other possible effects. As geographical distribution of semi-volatile OC is strongly influenced by air temperatures, future climate modifications will potentially enhance their physiological effects in lake ecosystems.     

Time trends of perfluorinated compounds from the sediment core of Tokyo Bay, Japan (1950s-2004)

Perfluorinated compounds (PFCs) were detected in sediment core samples collected in Tokyo Bay to reveal their time trends. The core sample deposited during 1950s-2004 was divided into two- to three-year intervals and the concentrations of 24 types of PFCs were determined. Perfluorooctane sulfonate (PFOS) decreased gradually from the early 1990s and its precursor decreased rapidly in the late 1990s, whereas perfluorooctanoic acid (PFOA) increased rapidly. The observed trends were regarded as a reflection of the shift from perfluorooctyl sulfonyl fluoride (PFOSF)-based products to telomer-based products after the phaseout of PFOSF-based products in 2001. The branched isomers of perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTrDA) were detected in the sample with its ratio of linear-isomer/branched-isomer concentrations decreasing. In this study, we revealed that the sediment core can serve as a tool for reconstructing the past pollution trend of PFCs and can provide interesting evidence concerning their environmental dynamics and time trend.     

Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain)

Blood biomarkers and levels of major pollutants in eggs and feathers were used to determine pollution effects in nestlings of the Purple Heron Ardea purpurea and the Little Egret Egretta garzetta, sampled on three Ebro River (NE Spain) areas: a reference site, a site affected by the effluents of a chlor-alkali industry and the river Delta. The two impacted heron populations showed mutually different pollutant and response patterns, suggesting different sources of contamination. In the population nesting near the chlor-alkali plant, elevated levels of hexachlorobenzene (HCB) and polychlorobiphenyls (PCBs) in eggs, and mercury in feathers in A. purpurea chicks were related with reduced blood antioxidant defenses and increased levels of micronuclei. In Ebro Delta, high levels of plasmatic lactate dehydrogenase in A. purpurea chicks and high frequency of micronuclei in blood of both species were tentatively associated with intensive agricultural activities taking place in the area. These results provide the first evidence of a biological response in heron chicks to the release of pollutants at a chlor-alkali plant.