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991.
太湖流域河流沉积物重金属分布及污染评估 总被引:27,自引:21,他引:6
为阐明经济发达地区河流表层沉积物重金属的污染特征,本研究分析了太湖流域典型水系94个样点沉积物中8种重金属(Zn、Cr、Ni、Cu、Pb、As、Cd和Hg)含量,评估了重金属的生态风险以及辨析了污染来源.结果表明,太湖流域河流表层沉积物中Zn、Cr、Ni、Cu、Pb、As、Cd和Hg的平均含量分别为163. 62、102. 46、45. 50、44. 71、37. 00、13. 34、0. 479和0. 109 mg·kg~(-1),均高于其对应的背景值(Hg除外).地累积指数评价中,Pb、Ni、Zn、Cu和Cd整体上处于低污染状态;在污染负荷指数评价中,Pb、Ni、Zn和Cu整体上处于中度污染状态,Cd、Cr、As处于低污染状态;在潜在生态风险评价中,Cd和Hg处于中等潜在生态风险,其余重金属均处于低潜在生态风险.多元统计分析表明,Pb主要来自于生活污水、农业废水排放;除受自然因素影响外,Cr、Ni和Zn还受到电镀及合金制造行业的影响; Cu和As主要来自于农药、工业废水; Cd主要来自于冶炼工业; Hg主要来源于化石燃料和石油产品的燃烧. 相似文献
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扬州市农作物秸秆综合利用现状及对策措施 总被引:1,自引:0,他引:1
通过对扬州市秸秆综合利用现状的调研和客观分析,提出秸秆综合利用"1+2+2"系统工程,即,"一个管理(制定法规和政策)、两个技术层次(集成技术应用、示范工程推广)以及两个重点(重点利用方式、重点示范区域)",找出解决农业秸秆综合利用出路的系统工程措施。 相似文献
995.
Ye Zhuang John H. Pavlish Nicholas B. Lentz Lucinda L. Hamre 《International Journal of Greenhouse Gas Control》2011
Oxycombustion is being considered as a promising solution to carbon capture and sequestration. Standard sampling and measurement methods may or may not be valid under oxycombustion conditions because the flue gas differs significantly from that of conventional air-blown coal combustion.Bench-scale tests were conducted to evaluate the measurement validity of continuous mercury monitors (CMMs), with and without a flue gas preconditioning unit, in a simulated oxycombustion flue gas with varied CO2 concentrations. Tests also included mercury capture with activated carbon in typical oxyfuel combustion flue gas. Research data indicated that highly concentrated CO2 streams affect the accuracy of the mass flow rate and the subsequent gaseous mercury measurement, although this is specific to the type of CMM. Concentrated CO2 streams also induced solid precipitation in the wet-chemistry conversion unit and resulted in a biased measurement of the gas-phase mercury. Flue gas dilution appeared to provide accurate measurement of total gas-phase mercury and be applicable to mercury measurement in highly concentrated CO2 streams, although mercury speciation appeared to be problematic and will require additional modification and validation. Mercury capture with activated carbon under CO2-enriched conditions showed similar performance to typical high-acid coal combustion flue gas. 相似文献
996.
氢能是有发展前景的新型能源之一,氢气的安全储存是氢能应用必须解决的问题。本文建立了基于大容量金属储氢装置的室内氢气泄漏扩散模型,利用计算流体力学软件FLUENT,对室内储氢罐的泄漏扩散过程进行数值模拟,得到了氢气泄漏扩散的速度分布、浓度分布。分析数值模拟结果,得出在该模拟条件下,氢气泄漏时的流动状态为射流湍流;泄漏后上浮扩散,空间密闭时积累于室顶;通风条件下大部分区域的氢气浓度仍然高于安全限值。通过数值模拟,总结出氢气在室内环境下的泄漏扩散规律,可为氢气泄漏事故的处理消防安全设置提供依据。 相似文献
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Liu J Liang X Yang J Ye Y Su M Nie Z Chen Y 《Journal of environmental monitoring : JEM》2011,13(10):2844-2850
The environmental risk of aquatic phosphorus (P) critically depends on its mobility and bioavailability, both of which are greatly affected by the size distribution and composition of P. The size distribution (particulate, colloidal and truly dissolved phase) of P, composed of molybdate reactive P (MRP) and molybdate unreactive P (MUP), was determined at twenty-three typical sections of the East Tiao River, China in the plum rain season. Results indicated particulate P was dominant followed by the truly dissolved P, while colloidal P was quantitatively the lowest in the whole river. From upstream to downstream, particulate P sharply increased, along with a slight decrease of truly dissolved P. However, colloidal P remained at a relatively stable level in the whole river, ranging from below detection limit to 0.025 mg L(-1), 0 to 13.4% of total P (TP). Furthermore, colloidal MRP exhibited a rising trend downriver as compared to upriver, with the notable transfer of MRP from the truly dissolved phase to particulate and colloidal phases. Particle concentration effect for colloids, observed in the study of MRP distribution, further corroborated the role of colloids in MRP solid/liquid partitioning. These observations, in this large-scale field investigation, fitted the "colloidal pumping" hypothesis. It may be concluded that colloids act as the intermediate and buffer in the dynamically balanced transfer of P from truly dissolved phase to large particulate phase, having a significant role in size distribution of P. 相似文献
1000.
Water quality parameters including TOC, UV(254), pH, chlorine dosage, bromide concentration and disinfection by-products were measured in water samples from 41 water treatment plants of six selected cities in China. Chloroform, bromodichloromethane, dibromochloromethane, dichloroacetic acid and trichloroacetic acid were the major disinfection by-products in the drinking water of China. Bromoform and dibromoacetic acid were also detected in many water samples. Higher concentrations of trihalomethanes and haloacetic acids were measured in summer compared to winter. The geographical variations in DBPs showed that TTHM levels were higher in Zhengzhou and Tianjin than other selected cities. And the HAA5 levels were highest in Changsha and Tianjin. The modeling procedure that predicts disinfection by-products formation was studied and developed using artificial neural networks. The performance of the artificial neural networks model was excellent (r > 0.84). 相似文献