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YuFeng Jiang LeiPing Shi ZhongFeng Mu Hang Sun HuiYing Zhan YingQin Wu 《毒物与环境化学》2017,99(5-6):824-836
Dibenzopyrene and its isomers are considered the most potent carcinogens of all polycyclic aromatic hydrocarbons tested to date. However, despite public concerns over their deleterious effects, they have not been extensively studied. The occurrence of four highly carcinogenic isomers of dibenzopyrene – dibenzo[def,p]chrysene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene in urban soil samples from Shanghai, China, have been determined in this study, as well as that of benzo[a]pyrene and coronene. A total of 14 peaks with ions at m/z 302 were detected by gas chromatography-mass spectrometry. Although the concentrations of benzo[a]pyrene and the sum of the 16 priority polycyclic aromatic hydrocarbons were greater than that of dibenzopyrene and its isomers, the carcinogenic potency of the latter was higher than that of benzo[a]pyrene. The results also indicate that the relative carcinogenic potency of the four dibenzopyrene isomers in the samples is higher than that of the 16 priority polycyclic aromatic hydrocarbons. 相似文献
485.
Application of Wavelet Coherence Method to Investigate Karst Spring Discharge Response to Climate Teleconnection Patterns 总被引:1,自引:0,他引:1 下载免费PDF全文
Xueli Huo Liyuan Lei Zhongfang Liu Yonghong Hao Bill X. Hu Hongbin Zhan 《Journal of the American Water Resources Association》2016,52(6):1281-1296
The impact of climate teleconnections on the regional hydrometeorology has been well studied, but very little effort has been made to relate climate teleconnections with groundwater flow variation. In this study, we used a wavelet coherence method to analyze monthly climate indices, precipitation, and spring discharge data, and investigated the relation between major teleconnection patterns (the Arctic Oscillation, North Atlantic Oscillation, Pacific Decadal Oscillation, El Niño‐Southern Oscillation, and Indian Ocean Dipole) and karst hydrological process in Niangziguan Springs Basin, China. The results indicate precipitation and spring discharges correlate well with climate indices at intra‐ and inter‐annual time scales. Further, the climate indices are mainly correlated with precipitation at shorter periodicities, but correlated with spring discharge at longer scales. The difference reflects the modulation of karst aquifers on precipitation‐spring discharge during the processes of precipitation infiltration into the ground, and subsequent transformation into spring discharge. When teleconnection signals are transmitted into spring discharge via precipitation infiltration and groundwater propagation, some high‐frequency climatic signals are likely to be filtered, attenuated, and delayed, thus only low‐frequency climatic signals are preserved in spring discharge. 相似文献
486.
Haidong Zhou Qingjun Zhang Xuelian Wang Qianqian Zhang Lixin Ma Yong Zhan 《Environmental science and pollution research international》2014,21(11):7113-7129
In this report, we refer to pharmaceuticals that are widespread in the urban aquatic environment and that mainly originate from wastewater treatment plants or non-point source sewage as “wastewater-marking pharmaceuticals” (WWMPs). To some extent, they reflect the condition or trend of water contamination and also contribute to aquatic environmental risk assessment. The method reported here for screening typical WWMPs was proposed based on academic concerns about them and their concentrations present in the urban aquatic environment, as well as their properties of accumulation, persistence, eco-toxicity and related environmental risks caused by them. The screening system consisted of an initial screening system and a further screening system. In the former, pharmaceuticals were categorised into different evaluation levels, and in the latter, each pharmaceutical was given a normalised final evaluation score, which was the sum of every score for its properties of accumulation, persistence, eco-toxicity and environmental risk in the aquatic environment. The system was applied to 126 pharmaceuticals frequently detected in the aquatic environment. In the initial screening procedure, five pharmaceuticals were classified into the “high” category, 16 pharmaceuticals into the “medium” category, 15 pharmaceuticals into the “low” category and 90 pharmaceuticals into the “very low” category. Subsequently, further screening were conducted on 36 pharmaceuticals considered as being of “high”, “medium” and “low” categories in the former system. We identified 7 pharmaceuticals with final evaluation scores of 1–10, 10 pharmaceuticals with scores of 11–15, 15 pharmaceuticals with scores from 16 to 20 and 4 pharmaceuticals with scores above 21. The results showed that this screening system could contribute to the effective selection of target WWMPs, which would be important for spatial-temporal dynamics, transference and pollution control of pharmaceuticals in the urban aquatic environment. However, there remains a number of pharmaceutical parameters with measured data gaps, such as organic carbon adsorption coefficients and bioconcentration factors, which, if filled, would improve the accuracy of the screening system. 相似文献
487.
为评价超声波预处理对城市污泥好氧/缺氧消化效果的影响,将超声波-好氧/缺氧消化工艺与传统的好氧/缺氧消化工艺进行了对比研究。结果表明,经25 d消化处理,引进超声波后的好氧/缺氧消化效果显著提高,污泥的VSS去除率达到51.98%,高于传统好氧/缺氧消化的42.98%。2种工艺消化的污泥TCOD以及污泥上清液中的SCOD、TP和NH3-N的变化趋势相似;而经超声波-好氧/缺氧消化的污泥上清液中硝态氮和亚硝态氮浓度较传统好氧/缺氧的高,说明经超声波处理后的污泥中的硝化细菌的活性增强,硝化反应加快。 相似文献
488.
采用中空纤维膜生物反应器(HFMBR)去除气态复合苯系物。挂膜后期,生物反应器的去除效率可以稳定达到80%左右(去除能力(EC)≥225 g/(m3.h))。研究了中空纤维膜生物反应器处理对于单一二甲苯以及混合二甲苯的性能,并且发现HFMBR对于去除单一二甲苯和混合二甲苯都有明显的效果,去除效率均达到90%以上;表明二甲苯之间竞争效应带来的相互抑制作用小。在低浓度的情况下,单一二甲苯和混合二甲苯的去除能力呈线性增加,在高浓度阶段,去除能力增加变缓。比较了混合二甲苯与甲苯联合降解,发现两者之间存在相互抑制作用,但相比传统生物反应器有明显的改善。与传统生物过滤系统比较而言,膜生物反应器有着很好的应用前景。 相似文献
489.
使用格子Boltzmann方法对含尘气体通过布袋滤料纤维的流动进行了数值模拟,采用拉格朗日方法跟踪了颗粒相中每个粒子的位置和速度并进行单向耦合计算。分析了气流通过纤维捕集体过程中的压降的变化规律,结果与达西渗透定律吻合。与此同时,对粒径小于1μm的气溶胶粒子在布袋纤维捕集体上的沉积规律展开了讨论。结果表明,粒径小于0.01μm的粒子的捕集主要受粒子的布朗随机扩散效应的控制;粒径大于0.1μm的粒子则主要依靠纤维滤料的拦截作用而沉积在捕集体表面;而粒径在0.01~0.1μm范围的粒子则具有较低的捕集效率。模拟结果为研究袋式除尘的过滤机理提供了依据。 相似文献
490.
研究微波诱导鳞片石墨-H2O 2催化氧化处理甲基紫废水工艺,探讨各种因素的协同作用及对废水脱色效果的影响,并采用SEM、EDX、XRD和FTIR对新鲜及使用6次后的鳞片石墨进行表征。结果表明,微波诱导鳞片石墨-H2O2能高效快速降解废水中的甲基紫;在50 mL初始pH为3,质量浓度为10 mg/L的甲基紫废水中, H2O2用量1 mL/L,鳞片石墨 3 g/L,微波输出功率259 W,微波辐射时间9 min的最佳处理工艺条件下,甲基紫脱色率达到了98.80%;微波、鳞片石墨、H2O2体系对甲基紫废水降解效果明显,产生协同效应。紫外-可见光谱分析表明,废水中甲基紫结构被破坏,但仍含有少量苯环等小分子。动力学研究表明,脱色反应符合一级反应动力学规律,反应速率常数k为0.42613 min-1,反应半衰期t1/2为1.626 min。 相似文献