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辽宁省大气可吸入颗粒物中重金属及多环芳烃污染特征研究 总被引:4,自引:0,他引:4
为全面了解辽宁省大气可吸入颗粒物污染状况,2004年在省内选取了5个城市进行分季节采样,并对颗粒物中重金属元素含量和美国优先控制的16种多环芳烃(PAHs)进行了定量研究。结果表明,大气PM10和PM2.5中重金属元素和PAHs污染较重,且冬季高于其它季节,重金属元素和PAHs主要富集在PM2.5及以下细小颗粒物中。 相似文献
364.
A toxicity-based method for evaluating safety of reclaimed water for environmental reuses 总被引:1,自引:0,他引:1
A large quantity of toxic chemical pollutants possibly remains in reclaimed water due to the limited removal efficiency in traditional reclamation processes. It is not enough to guarantee the safety of reclaimed water using conventional water quality criteria. An integrated assessment method based on toxicity test is necessary to vividly depict the safety of reclaimed water for reuse. A toxicity test battery consisting of lethality, genotoxicity and endocrine disrupting effect was designed to screen the multiple biological effects of residual toxic chemicals in reclaimed water. The toxicity results of reclaimed water were converted into the equivalent concentrations of the corresponding positive reference substances(EQC). Simultaneously, the predicted no-effect concentration(PNEC) of each positive reference substance was obtained by analyzing the species sensitivity distribution(SSD) of toxicity data. An index "toxicity score" was proposed and valued as 1, 2, 3, or 4 depending on the ratio of the corresponding EQC to PNEC. For vividly ranking the safety of reclaimed water, an integrated assessment index "toxicity rank" was proposed, which was classified into A, B, C, or D rank with A being the safest. The proposed method was proved to be effective in evaluating reclaimed water samples in case studies. 相似文献
365.
Release Characteristics of Nutrients from Polymer-coated Compound Controlled Release Fertilizers 总被引:2,自引:0,他引:2
Reliable information regarding release characteristics of nutrients from a polymer-coated controlled release fertilizer (CRF) is essential for beneficial agronomic and environmental results. Significant knowledge regarding nitrogen release from polymer-coated urea was gained while the information regarding the release of the different nutrients contained in polymer-coated compound N–P–K CRF remains limited. An experiment in which major factors affecting the differential release of nutrients from two coated compound CRF was performed in free water, water saturated sand and sand at field capacity. In general, nitrate release was the fastest, followed by ammonium and potassium whereas phosphate was significantly slower, with a rate of linear release in free water 45–70% slower than that of nitrate. Little differences were obtained for the lag periods of nitrate, ammonium and potassium release (2–10 days) under the experimental conditions, whereas for P they were one order of magnitude larger. The main factor slowing the release was assumed to be the lower solubility of ions with P being the least soluble. Release into free water was, expectedly, somewhat faster than that into saturated sand and significantly faster as compared to sand at field capacity and particularly so for P. Raising the temperature from 20 °C to 40 °C increased the rate of linear release of the different nutrients. The energy of activation, EArel, estimated for the linear release, of the different nutrients, was narrow ranging between 37 to 46 (KJ mol−1) whereas the mean values obtained for the two CRF, differing by 50% in coating thickness, was non-significant. However, EArel was significantly different in different media. The complex effect of temperature on the lag period and nutrient interactions during release deserve further investigation. 相似文献
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MDAT-IAT同步脱氮除磷工艺活性污泥在不同基质中的厌氧释磷特性研究 总被引:6,自引:2,他引:6
对改进型MDATIAT(ModifiedDemandedAerationTankIntermittentAerationTank)同步脱氮除磷工艺中活性污泥在不同基质下的厌氧释磷特性进行了研究.在葡萄糖、甲酸钠、乙酸钠和丙酸钠4种单一基质中,活性污泥厌氧释磷量分别为1.58、3.55、3.04和1.86mg·L-1;释磷速率分别达到0.02、0.05、0.15和0.10mg·L-1·min-1.另外,在葡萄糖、甲酸钠、乙酸钠和丙酸钠组成的混合基质中的活性污泥厌氧释磷试验结果表明,混合基质中活性污泥释磷量和释磷速率均大于4种单一基质中的释磷量和释磷速率,分别达到8.51mg·L-1和0.31mg·L-1·min-1. 相似文献
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Xiaolong Li Congcong Ding Jiali Liao Liang Du Qun Sun Jijun Yang Yuanyou Yang Dong Zhang Jun Tang Ning Liu 《环境科学学报(英文版)》2016,28(3):162-171
The biosorption mechanisms of uranium on an aerobic bacterial strain Streptomyces sporoverrucosus dwc-3, isolated from a potential disposal site for (ultra-)low uraniferous radioactive waste in Southwest China, were evaluated by using transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), proton induced X-ray emission (PIXE) and enhanced proton backscattering spectrometry (EPBS). Approximately 60% of total uranium at an initial concentration of 10 mg/L uranium nitrate solution could be absorbed on 100 mg S. sporoverrucosus dwc-3 with an adsorption capacity of more than 3.0 mg/g (wet weight) after 12 hr at room temperature at pH 3.0. The dynamic biosorption process of S. sporoverrucosus dwc-3 for uranyl ions was well described by a pseudo second-order model. S. sporoverrucosus dwc-3 could accumulate uranium on cell walls and within the cell, as revealed by SEM and TEM analysis as well as EDX spectra. XPS and FT-IR analysis further suggested that the absorbed uranium was bound to amino, phosphate and carboxyl groups of the cells. Additionally, PIXE and EPBS results confirmed that ion exchange also contributed to the adsorption process of uranium. 相似文献
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