Distribution and source of microplastics in China's second largest reservoir - Danjiangkou Reservoir

Fresh water microplastic pollution is of pressing concern globally, but its distribution and sources in reservoirs are poorly documented. Danjiangkou Reservoir is the second largest reservoir in China and is divided into the Han Reservoir and Dan Reservoir. In this work, microplastic abundances and morphological characteristics of the reservoir were investigated. The microplastic abundance of 15 main tributaries of the reservoir was also measured. The vertical distribution (in water column and sediment), horizontal distribution (in Han Reservoir and Dan Reservoir) and source of microplastics were analyzed. Microplastics accumulated in the middle layer of the reservoir, and the size and color of the microplastic particles changed from the surface to the bottom, which implies that surveys of surface water are not enough to determine the microplastic contamination for deep water reservoirs. In the surface water, the microplastic abundance in the Han Reservoir was lower than that in the Dan Reservoir (p < 0.05), but microplastic abundance did not differ significantly in the intermediate and bottom water. Tributaries were one of the main sources of microplastics for Han Reservoir but not for Dan Reservoir. Agricultural cultivation in the hydro-fluctuation belt might be an important source of microplastics in the Dan Reservoir, which should be given additional attention. The results of this study can provide valuable information for developing microplastic sampling strategies in deep water reservoirs. Further studies are recommended to investigate the process through which microplastics in the hydro-fluctuation belt enter the reservoir and the sinking behavior of microplastics in the reservoir.     

Chemical characteristics, oxidative potential, and sources of PM2.5 in wintertime in Lahore and Peshawar, Pakistan

The chemical characteristics, oxidative potential, and sources of PM_2.5 were analyzed at the urban sites of Lahore and Peshawar, Pakistan in February 2019. Carbonaceous species, water soluble ions, and metal elements were measured to investigate the chemical composition and sources of PM_2.5. The dithiothreitol (DTT) consumption rate was measured to evaluate the oxidative potential of PM_2.5. Both cities showed a high exposure risk of PM_2.5 regarding its oxidative potential (DTT_v). Carbonaceous and some of the elemental species of PM_2.5 correlated well with DTT_v in both Lahore and Peshawar. Besides, the DTT_v of PM_2.5 in Lahore showed significant positive correlation with most of the measured water soluble ions, however, ions were DTT-inactive in Peshawar. Due to the higher proportions of carbonaceous species and metal elements, Peshawar showed higher mass-normalized DTT activity of PM_2.5 compared to Lahore although the average PM_2.5 concentration in Peshawar was lower. The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities. Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM_2.5 and its oxidative potential. Mixed sources of traffic and road dust resuspension and coal combustion, direct vehicle emission, and biomass burning and formation of secondary aerosol were identified as the major sources of PM_2.5 in both cities. The findings of this study provide important data for evaluation of the potential health risks of PM_2.5 and for formulation of efficient control strategies in major cities of Pakistan.     

安全技术说明书在油田化学助剂危害因素识别中存在问题探讨

以3种化学助剂的化学品安全技术说明书(SDS)信息与气相色谱-质谱联用仪定性分析结果为对比,探讨了油田化学助剂安全技术说明书在完整性、真实性、准确性等方面存在的问题,建议完善SDS审核与监督机制,在识别有害因素时根据SDS、定性定量检测结果、生产工艺及原辅材料分析等内容做出综合判断,使用化学助剂时核实SDS准确性及化学助剂安全性,以采取正确的防控措施。     

铝穹顶储罐雷击损伤及燃爆风险研究

针对铝穹顶储罐雷击问题,开展了回击后长持续时间雷电流分量作用下的铝合金板烧蚀损伤试验研究,分析了铝穹顶储罐损伤及油气燃爆风险。结果表明:当直流分量为164 C时,2 mm铝板发生穿孔,铝穹顶储罐存在雷击燃爆风险;当直流分量≤157 C时,未穿孔,背面温度最高为480℃,存在燃爆风险,铝穹顶储罐存在雷击燃爆风险;当直流分量196 C时,4 mm铝板发生穿孔;当直流分量为196 C时,6 mm铝板未发生穿孔,背面温升为125℃,小于205℃,铝穹顶储罐不存在雷击燃爆风险。     

控制回路的多维度性能评估方法研究

为评价炼化装置中各控制回路的性能,基于控制回路关键品质指标要求,采用控制回路的设定值、输出值、测量值、控制模式等过程参数设计了准确性指标、稳定性指标及快速性指标等性能评估指标。辅助技术人员在线进行控制回路性能评估,识别性能较差的控制回路,诊断异常原因并进行优化,提高装置的自动化水平。     

四川省生活垃圾处理设施运行现状及存在问题分析

根据对四川省生活垃圾处理设施运行情况的现场调研,对全省生活垃圾的处理概况和垃圾处理设施的建设运行现状以及目前四川省生活垃圾无害化处理存在的问题和形成原因进行了分析,并提出建议,为政府决策提供参考,为同行实施建设、管理提供帮助。     

Glass recycling in cement production--an innovative approach

An innovative approach of using waste glass in cement production was proposed and tested in a laboratory and cement production plant. The laboratory characterization of 32 types of glass show that the chemical composition of glass does not vary significantly with its color or origin but depends on its application. The alkali content of glass, a major concern for cement production varies from 0 to 22%. For the glass bottles mainly found in Hong Kong waste glasses, the alkali content (Na2O) ranges from 10 to 19% with an average around 15%. There is no significant change of the SO2 content in the gas exhaust of the rotary kiln when about 1.8 t/h of glass bottles were loaded along with the 280-290 t/h raw materials. The content of NOx, mainly depends on the temperature of the kiln, does not show significant change either. The SO3 content of the clinker is comparable with that obtained without the loading of glass. The alkaline content shows a slight increase but still within three times the standard deviation obtained from the statistical data of the past year. The detailed analysis of the quality of the cement product shows that there is not any significant impact of glass for the feeding rate tested.     

天津海域底质重金属分布与矿物质特征研究

文中研究了渤海湾天津海域沉积物中重金属的空间分布特征,在此基础上进行了元素间的相关分析,以进一步分析元素间共同的分布趋势;同时对该海域表层沉积物矿物组合做了分析。结果表明,沉积物重金属平面分布特征总体上表现为河口附近含量高,口外低的趋势;垂直分布特征由于受沿岸不同污染源的污染影响,重金属污染物难以形成一定规律的分布状态,总体上呈波折型分布;该海域各重金属相关性非常明显,反映了这些重金属元素间共生共存的地球化学特性;渤海表层沉积物中含有5%的闪石和白云石,闪石和白云石是渤海湾沉积物的重要标志矿物;渤海湾表层沉积物中粘土矿物组合为伊利石和绿泥石,其平均含量分别为56%和44%。     

基于LCA的钢铁联合企业CO_2排放影响因素分析

钢铁企业是CO2排放大户,减少吨钢CO2排放是钢铁企业节约能源、保护环境、走可持续发展道路的必然要求.本研究旨在对钢铁企业产品生命周期清单研究的基础上,识别钢铁企业CO2排放的主要影响因素,提出针对性的减排建议.以某钢铁联合企业的产品生命周期清单模型为平台,同时利用TornadoChart工具,计算得到对企业CO2排放影响较大的因素,然后提出了相应的减排措施.结果表明,转炉流程对于钢铁企业的影响要大于电炉流程;对该企业CO2排放有重大影响和相关影响的因素有:高炉煤气(BFG)的CO2排放系数、连铸坯的钢水单耗、热轧的板坯单耗、转炉的铁水比.减少钢铁联合企业CO2排放的有效措施是采取捕集BFG中的CO2、降低转炉的铁水比、加强副产煤气的回收以及优化企业的产品生产结构.     

Environmental risks and the potential benefits of nanopesticides: a review

Environmental Chemistry Letters - With the escalating food demand of the ever-increasing global population and the rapid development of nanotechnology, nanopesticides are being proposed as...