Pilot study of the polychlorinated dibenzo-p-dioxins and dibenzofurans level in agricultural soil in Shanghai, China

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in agricultural soil samples from Shanghai to determine levels and to identify possible dioxin sources. The dioxin level was measured by an enzyme immunoassay method, US EPA 4025 (modified), which provides results as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents. The Method 4025m results obtained from 60 soil samples displayed a normal distribution, ranging from 2.8 to 23.4 pg/g 2378-TCDD-equvalents, with an average of 11.0 pg/g. The result also revealed a similar PCDD/Fs concentration among crop usage patterns, but differences by geographic region, low in the southwest of Shanghai and considerably higher in the northwest region. In contrast, the dioxin concentrations on Chongming Island were fairly homogeneous, with a range 10–15 pg/g. This immunoassay method is an effective high throughput screening tool which helps to minimize the need for more expensive analyses.     

Transport of Sr2+ and SrEDTA2- in partially-saturated and heterogeneous sediments

Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr(2+) and SrEDTA(2-). The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA(2-) complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr(2+) as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr(2+) and SrEDTA(2-) suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA(2-), MnEDTA(2-), PbEDTA(2-), and unidentified Sr and Ca complexes. Displacement of Sr(2+) through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that sandy sediments of low water content constituted the immobile flow regime. Our results suggested that the sequestration of Sr(2+) in partially-saturated, heterogeneous sediments was most likely due to the formation of immobile water in drier regions having low hydraulic conductivities.     

“四沿”化工企业污水处理系统安全事故状态下负荷缓冲及安全环境(SE)联锁探讨

在对"四沿"(沿江、沿河、沿湖、沿海)化工行业污水处理方法及流程特点总结的基础上,归纳出应对水力和污染物冲击负荷的缓冲方法。为克服缓冲控制能力有限的缺点,提出一种新方法——SE(安全和环境)联锁,以期达到完善管理、提高控制效果的目的,并详细阐述了该方法在管理及技术层面的实施途径。     

基于临水区域化工园区的整体安全研究

针对临水区域化工园区的生产特点及在整体安全方面存在的普遍问题,提出在临水区域化工园区内要进行合理布局,做到功能分区明确;同时需建立园区安全生产管理、监测预警及应急处置系统,主要是由固定危险源和移动危险源动态安全管理子系统、安全生产监测预警系统、突发事故应急处置平台等所组成;坚持安全监控信息化与标准化,对化工园区的整体安全性的提高将发挥巨大的作用,为建设"平安园区"打下坚实的基础。     

Radiation-induced degradation of methyl orange in aqueous solutions

Degradation of methyl orange under gamma-irradiation was investigated. The reactions followed pseudo first-order kinetics. Apparent degradation rate constant, estimated through linear regression analysis, increased with an increase of dose rate and a decrease of initial methyl orange concentration. Degradation of methyl orange was significantly accelerated under oxidative condition, but was slightly enhanced under reductive condition. However, the result of decoloration was better under reductive condition than oxidative one. An analysis on the intermediates using Fourier transform infrared and gas chromatography/mass spectrometry demonstrates that the radiolytic degradation of methyl orange was processed with different C-N cleavages under oxidative and reductive conditions.     

应用陶粒过滤-陶瓷膜组合对止咳糖浆制药废水深度处理的试验研究

止咳精浆制药废水经生物接触氧化一体化废水处理装置处理后,其出水中COD、BOD和氨氮等主要污染物质均不能达标排放.在实验室中采用陶粒过滤-陶瓷膜组合对经一体化处理装置处理后的制药废水进行深度处理,在陶粒柱反应器选用粒径为1～2 mm的陶粒滤料,陶瓷膜反应器选用孔径为2～3/μm陶瓷膜的条件下对水样进行测试.废水经陶粒过滤-陶瓷膜组合处理后,其BOD、COD、SS和氨氮指标均可稳定达标排放.     

非饱和土石坝渗流分析

传统的渗流分析主要考虑饱和区而忽略非饱和区内的渗流,本文基于饱和-非饱和渗流计算原理,采用有限元法考虑了非饱和区渗流的影响,并以各向同性均质坝和心墙土石坝为算例进行计算分析。算例表明,由于基质吸力产生的虹吸作用,使得浸润线上部的非饱和区内也存在着连续的水流,通过分析这种水流的特点,定性地得出其对土石坝渗流稳定性的影响。     

利用餐饮业废油脂制造生物柴油

世界的石油产量将会逐渐减少,石化柴油燃烧后所排放的废气是造成的城市空气污染的主要原因,生物柴油是石化柴油很好的替代能源,文章介绍了国外废油脂处理利用和甸餐饮业废油脂的概况,提出了利用餐饮业废油脂制造生物柴油的方法和工艺流程,并讨论了利用餐饮业废油脂制造生物柴油的几个问题。     

硫酸含汞问题的追踪研究

以辽宁省最大的硫酸生产企业（辽西某锌厂）为研究对象,剖析了硫酸含汞问题的来源,论述了该厂原料、中间产品、最终产品、车间内外环境汞的污染状况。并论述了使用该厂硫酸的十大企业的中间产品、最终产品的含汞状况,给出了厂内外环境受汞污染的测定结果,研究表明含汞硫酸污染问题是急待解决的重要问题。