基于梯形模糊数的地表灰尘重金属污染健康风险评价模型

将梯形模糊数引入环境健康风险评价领域,构建了城市地表灰尘重金属污染健康风险评价模糊模型,提出了健康风险等级判别方法和具有模糊化特征的风险等级判别标准.同时,选取重金属Zn、Pb、Cu、Cd和Cr为评价因子,将基于梯形模糊数的健康风险评价模型和风险等级识别方法应用于合肥市城区地表灰尘重金属污染的健康风险评价中.结果表明,地表灰尘中Cd和Cr的致癌风险均很低,期望值分别为1.49×10-9和2.75×10-7,低于美国环保署（USEPA）推荐值10-6;Cd和Cr致癌总风险对Ⅰ级风险的隶属度为0.927,因此属于极低风险水平.儿童的地表灰尘重金属非致癌总风险期望值为1.888,超过了安全阈值1.0,而成人的非致癌总风险期望值仅为0.278;儿童和成人健康风险的主要暴露途径都是手-口直接摄入.     

水培海马齿对海水菲污染修复作用的初步研究

采用水培法研究了海洋滩涂耐盐植物海马齿(Sesuvium portu lacastrum Linn.)对海水菲污染的修复作用.结果显示,实验4d后,不种植海马齿的对照组、种植海马齿的抑菌组和不抑菌组海水中菲浓度分别从0.988、0.942和0.957mg·L-1降至0.553、0.185和0.070mg·L-1,降低了44.0%、80.4%和92.7%;与对照组相比,抑菌组(T1)和不抑菌组(T2)海水中菲的去除率分别提高了36.4%和48.7%,不抑菌组又比抑菌组高12.3%.利用差减法计算的结果显示,在与自然水体接近的不抑菌条件下,菲的非生物损失、海马齿的作用和微生物的作用,三者对海水中菲浓度降低(92.7%)的贡献分别为44.0%、36.4%和12.3%,海马齿植株内菲的积累量则仅占海水中菲减少量的2.6%.研究表明,水培海马齿可明显提高菲污染海水中菲的去除率,其中,植物与微生物共同发挥着重要的作用,但植物积累不是海马齿修复海水菲污染的主要机制.     

三维电极生物膜反应器全程自养脱氮的启动研究

采用人工配制氨氮废水,对三维电极生物膜反应器进行全程自养脱氮的启动研究.反应器中阳极采用钌涂层钛棒,在阳极区电解水产氧供硝化菌进行硝化反应;阴极采用活性炭纤维毡,并在阴极区填充活性炭颗粒构建三维电极,在阴极区电解水产氢供反硝化菌完成反硝化过程.在进水NH₄⁺-N浓度30 mg·L^-1、温度30 ℃、HRT为24 h的试验条件下,通过调节DO和 pH实现对硝化和反硝化反应的控制.结果表明,经过挂膜、驯化、稳定这3个较为典型的阶段后,反应器对NH₄⁺-N去除率达到了97.8%,TN的去除率为92.4%,成功实现了三维电极生物膜反应器全程自养脱氮的启动.扫描电镜结果显示,阴极活性炭纤维毡表面的细菌主要为短杆状假单胞菌,活性碳颗粒表面的细菌为微球反硝化细菌,同属氢自养反硝化细菌,反应器中稳定的自养脱氮系统逐步建立.     

气体稳定同位素比质谱法分析本底大气CO2的δ13C和δ18O

将商用MAT253稳定同位素比质谱仪、Airtrap高效预浓缩气体捕集阱与自加工16口自动进样器集成,建立了高精度气体稳定同位素比质谱分析系统,用于程序化自动分析本底大气CO2的δ13C和δ18O.气样分析时用工作标气定量并穿插目标气测定,还定期用实验室上一级标气对工作标气和参比气进行标校,以保证分析结果的可靠和可比.结果表明,利用不同稳定同位素比范围的标气重复进样测试,发现该系统对δ13C和δ18O的分析精度分别优于0.03‰和0.06‰,能基本满足本底大气CO2的碳氧稳定同位素比分析需求和WMO/GAW质量目标.     

Chlorobenzenes and organochlorinated pesticides in vegetable soils from an industrial site, China

Organochlorinated compounds are ubiquitous contaminants in the environment, especially in industrial sites. The objective of the work was to investigate whether a vegetable field near an industrial site is safe for vegetable production. The residues of chlorobenzenes (CBs), hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in a vegetable field which was near a chemical plant in China were characterized. Point estimate quotient was used for ecological risk assessment of the investigated site. The results showed that all CBs except monochlorobenzene (MCB) were detected in soils. The total concentrations of ∑CBs ranged from 71.06 to 716.57 ng/g, with a mean concentration of 434.93 ng/g. The main components of CBs in soil samples were dichlorobenzenes (DCBs), trichlorobenzenes (TCBs) and tetrachlorobenzenes (TeCBs), while for single congeners, 1,2,4-TCB had the highest concentration, which ranged from 13.21 to 210.35 ng/g with a mean concentration of 111.89 ng/g. Residues of hexachlorobenzene (HCB) in soil samples ranged from 0.9 to 11.79 ng/g, significantly lower than ∑DCB, ∑TCB and ∑TeCB. Concentrations of ∑HCHs and ∑DDTs in soils ranged from 11.32 to 55.24 ng/g and from 195.63 to 465.58 ng/g, respectively, of which the main components were αup-HCH and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE). Ecological risk assessment for the investigated site showed that the most potential risks were from TCBs and TeCBs, based on the hazard quotients. The higher residues of CBs and DDTs compared to the target values and the higher than 1 hazard quotients indicated that this area is not safe for vegetable production and thus soil remediation is needed.     

Combined remediation of DDT congeners and cadmium in soil by Sphingobacterium sp. D-6 and Sedum alfredii Hance

Combined pollution of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and cadmium (Cd) in agricultural soils is of great concern because they present serious risk to food security and human health.In order to develop a cost-effective and safe method for the removal of DDTs and Cd in soil,combined remediation of DDTs and Cd in soil by Sphingobacterium sp.D-6 and the hyperaccumulator,Sedum alfredii Hance was investigated.After treatment for 210 days,the degradation half-lives of DDTs in soils treated by strain D-6 decreased by 8.1% to 68.0% compared with those in the controls.The inoculation of strain D-6 into soil decreased the uptake of DDTs by pak choi and S.alfredii.The shoots/roots ratios of S.alfredii for the Cd accumulation ranged from 12.32 to 21.75.The Cd concentration in soil decreased to 65.8%-71.8% for S.alfredii treatment and 14.1%-58.2% for S.alfredii and strain D-6 combined treatment,respectively,compared with that in the control.The population size of the DDTs-degrading strain,Simpson index (1/D) and soil respiratory rate decreased in the early stage of treatment and then gradually increased,ultimately recovering to or exceeding the initial level.The results indicated that synchronous incorporation of strain D-6 and S.alfredii into soil was found to significantly (p 0.05) enhance the degradation of DDTs in soil and the hyperaccumulation of Cd in S.alfredii.It was concluded that strain D-6 and S.alfredii could be used successfully to control DDTs and Cd in contaminated soil.     

Photoelectrocatalytic degradation of high COD dipterex pesticide by using TiO2/Ni photo electrode

A TiO₂ thin film electrode deposited on porous nickel net (TiO₂/Ni) was prepared by the sol-gel method, and the surface morphology, crystal structure features and the grain size were characterized by Field emission scan electron microscopy (FESEM) and X-ray diffraction (XRD). The photoelectrocatalytic system was set up using a UV high-pressure mercury lamp as the light source, TiO₂ coated on foamed nickel as photo anode, Pt sheet as counter electrode and the pesticide dipterex in synthetic wastewater. Various factors that influence the photoelectrocatalytic decomposition of dipterex pesticide have been studied, such as degradation time, the type of electrolyte, current density, original pH value and different degradation methods. The prepared catalysts were employed to photoelectrocatalytically degrade the pesticide dipterex under UV irradiation, comparing the results with photocatalytic degradation and electrochemical oxidation. The results indicated that under the optimal conditions of 0.02 mol/L NaCl as the supporting electrolyte, current density = 2.5 mA/cm², pH 6.0 and dipterex pesticide 40 mg/L, and reaction time 2 hr, dipterex chemical oxygen demand (COD) removal rate and organophosphorous conversion of up to 82.6% and 83.5% were achieved, respectively. The method of photoelectrocatalytic degradation is more efficient than photocatalysis and electrochemical oxidation. The possible roles of the electrolytes on the reactions and probable mechanisms were also discussed.     

Effect of vegetation of transgenic Bt rice lines and their straw amendment on soil enzymes, respiration, functional diversity and community structure of soil microorganisms under field conditions

With the development of transgenic crops, there is an increasing concern about the possible adverse effects of their vegetation and residues on soil environmental quality. This study was carried out to evaluate the possible effects of the vegetation of transgenic Bt rice lines Huachi B6 (HC) and TT51 (TT) followed by the return of their straw to the soil on soil enzymes (catalase, urease, neutral phosphatase and invertase), anaerobic respiration activity, microbial utilization of carbon substrates and community structure, under field conditions. The results indicated that the vegetation of the two transgenic rice lines (HC and TT) and return of their straw had few adverse effects on soil enzymes and anaerobic respiration activity compared to their parent and distant parent, although some transient differences were observed. The vegetation and subsequent straw amendment of Bt rice HC and TT did not appear to have a harmful effect on the richness, evenness and community structure of soil microorganisms. No different pattern of impact due to plant species was found between HC and TT. It could be concluded that the vegetation of transgenic Bt rice lines and the return of their straw as organic fertilizer may not alter soil microbe-mediated functions.     

浅谈声学材料在排水管道降噪中的应用

对于我国现有的建筑物来说,许多年代较早的已建成建筑物都没有考虑到排水管道噪声给人们的居住环境带来的困扰。对于这种建筑为避免其噪声问题,进行排水管道的全部改造显然是不可行的,利用声学材料隔声包扎是一种有效、快速、经济的解决方法。本文利用电声学实验进行了声学材料与管材的组合包扎,分析了管材在不同频段的最适宜包扎材料,根据排水噪声特性选出最佳降噪材料。     

甘肃大剧院室内设计及声学设计与施工

介绍甘肃省大剧场室内施工阶段修改扩建建筑大堂的进深满足大堂空间声场视觉要求、解决并优化了会议室的吸声要求及空间落差、增加了上下场门声闸、大堂吸声天花的重量、弥补了观众厅吸声面积过大的过失,调整乐池吸声材料面积。对大剧院设计元素简化统一突出文化内含,调整楼座坐位处轮廓造型避免声聚焦的形成。