Effects of pond salinization on survival rate of amphibian hosts infected with the chytrid fungus

The chytrid fungus Batrachochytrium dendrobatidis has been implicated in the decline and extinction of amphibian populations worldwide, but management options are limited. Recent studies show that sodium chloride (NaCl) has fungicidal properties that reduce the mortality rates of infected hosts in captivity. We investigated whether similar results can be obtained by adding salt to water bodies in the field. We increased the salinity of 8 water bodies to 2 or 4 ppt and left an additional 4 water bodies with close to 0 ppt and monitored salinity for 18 months. Captively bred tadpoles of green and golden bell frog (Litoria aurea) were released into each water body and their development, levels of B. dendrobatidis infection, and survival were monitored at 1, 4, and 12 months. The effect of salt on the abundance of nontarget organisms was also investigated in before and after style analyses. Salinities remained constant over time with little intervention. Hosts in water bodies with 4 ppt salt had a significantly lower prevalence of chytrid infection and higher survival, following metamorphosis, than hosts in 0 ppt salt. Tadpoles in the 4 ppt group were smaller in length after 1 month in the release site than those in the 0 and 2 ppt groups, but after metamorphosis body size in all water bodies was similar . In water bodies with 4 ppt salt, the abundance of dwarf tree frogs (Litoria fallax), dragonfly larvae, and damselfly larvae was lower than in water bodies with 0 and 2 ppt salt, which could have knock‐on effects for community structure. Based on our results, salt may be an effective field‐based B. dendrobatidis mitigation tool for lentic amphibians that could contribute to the conservation of numerous susceptible species. However, as in all conservation efforts, these benefits need to be weighed against negative effects on both target and nontarget organisms.     

氯化钠/纳米疏水二氧化硅超细干粉制备及灭火性能研究

选用氯化钠为基体制备金属火灾超细干粉灭火剂。应用反溶剂法对其改性,使纳米疏水二氧化硅吸附在氯化钠晶体表面,其中分散剂为PEG-1000。结果表明,纳米疏水二氧化硅的添加有利于细化氯化钠颗粒,但过量的添加会起反作用,最佳用量为3 wt%左右,平均粒径为2.18μm。镁片灭火实验证明超细复合干粉的灭火性能明显好于传统氯化钠灭火剂(商用D类灭火剂),纳米疏水二氧化硅最佳添加量为3 wt%,此时灭火时间仅需传统灭火剂的一半。最后利用FDS5.0模拟干粉颗粒与燃烧火焰作用过程,模拟结果表明干粉覆盖对火焰具有一定的抑制效果,并分析了复合干粉灭火机理。     

聚合氯化铝铁絮凝剂的性能研究

煤矸石是采煤过程之废料。本文利用煤矸石制备出了聚合氯化铝铁（ＰＡＦＣ）：一种新型无机高分子絮凝剂，探讨了Ｆｅ＾３＋的稳定性与溶液离子强度之间的关系，发现溶液的离子强度越大，则产生Ｆｅ（ＯＨ）３沉淀时的ＰＨ越高。研究了ＰＡＦＣ水解产物的ζ电位及絮凝效果随ＰＨ的变化情况，比较了ＰＡＦＣ、ＰＡＣ和ＰＦＳ的除浊性能，ＰＡＦＣ在ＰＨ为７．０－８．２范围内除浊效果最佳，ＰＡＦＣ的除浊效果优于ＰＡＣ。     

五氯酚对鱼鳃丝组织结构及电解质元素的影响

利用场发射扫描电镜观察了罗非鱼在0．05mg L^-1和0．10mg L^-1五氯酚(PCP)中暴露3d，7d和10d后鳃丝上皮组织结构的变化，以及扫描电镜／X-射线能谱联用仪定量分析鳃丝中主要电解质元素Na，Ca和Cl的变化．与CK比较，随着暴露时问的延长和暴露浓度的增加，泌氯细胞出现的密度增加，部分泌氯细胞个体的面积也增大，扁平上皮细胞的微脊碎片数量增加，排列散乱，细胞受损现象明显；鳃丝中Na，Ca和Cl元素的含量总体上呈下降的趋势，在一定程度上说明与Ca^2 、Na^ 和Cl^-运转有关的酶的活性受到抑制．图2参14     

聚硫氯化铝絮凝效果及在水处理中的应用

采用聚硫氯化铝（ＰＡＣＳ）为絮凝剂进行废水处理试验,对其絮凝效果及影响因素进行了研究,试验结果表明,ＰＡＣＳ的ＳＯ４＾２－含量,碱化度,投加量和水的ｐＨ对絮凝效果有影响,当Ａｌ＾３＋／ＳＯ４＾２－（摩尔比）为１４￣１６,碱化度为６５％￣７０％,ｐＨ为６￣９、ＰＡＣＳ投加量为２￣４ｍｇ／Ｌ时,絮凝效果最佳,试验结果还表明,ＰＡＣＳ比聚氯化铝（ＰＡＣ）的絮凝效果好。     

Polyvinyl chloride used as a chlorinating and a reducing agent

Polyvinyl chloride (PVC) or vinyl is a recyclable material. It can be used as a chlorinating and a reducing agent. Two tests of chlorination and reduction of two different samples of jarosite and hematite were realized using PVC, results are presented in this paper. The chlorination test shows that the HCl gas produced from PVC and heated at ≈250°C can be used as a chlorine source to recover as chlorinated compounds the valuable metals such as Zn, Pb contained in jarosite. The XRD reveals the presence of lead and zinc chlorides in the condensates obtained. The second test of reduction was conducted using a mixture of PVC and hematite treated in a nitrogen atmosphere between 200 and 1000°C. The results show that at low temperature, PVC produces HCl and with kinetic consideration, no reactions can be observed with hematite. However, at high temperature, the weight of the hematite sample decreases by ≈15%, due to the reduction of hematite to iron metal.     

聚合铝混凝过程研究:不同形态硅酸的影响作用

研究了不同形态硅酸对聚合铝混凝过程的影响作用 .实验结果表明经预制形成的具有不同形态分布组成的硅酸与聚合铝 ,在投加后相互间发生了十分复杂的物理化学作用 ,并受溶液pH值的影响 ,从而最终决定了混凝效果 .反应过程中所生成的形态产物及其物化特征 ,很大程度上取决于聚合铝碱化度以及所投加的Si Al比 .其中碱化度越高 ,最终产物所带电荷越高 .而不同硅酸所起影响作用分别取决于聚合程度 ,在与聚合铝反应过程中表现出一定的规律性 .单体硅酸与单体铝迅速发生较强的络合作用 ,抑制了多聚水解铝阳离子的形成 .聚合硅酸则倾向于与聚合铝形态相互作用形成一定的胶状化合物 ,从而在溶液中稳定存在 .对于胶体硅酸 ,在聚合铝作用下迅速凝聚形成更大的聚集体 ,在颗粒物间架桥形成粗大的絮体 .所得结果对混凝机理的解释与复合混凝剂的发展提供了一定的参考作用     

Simulated and experimental evaluation of factors affecting the rate and extent of reductive dehalogenation of chloroethenes with glucose

Carbohydrates such as molasses are being added to aquifers to serve as electron donors for reductive dehalogenation of chloroethenes. Glucose, as a model carbohydrate, was studied to better understand the processes involved and to evaluate the effectiveness for dehalogenation of different approaches for carbohydrate addition. A simulation model was developed and calibrated with experimental data for the reductive dehalogenation of tetrachloroethene to ethene via cis-1,2-dichloroethene. The model included fermentors that convert the primary donor (glucose) into butyrate, acetate and hydrogen, methanogens, and two separate dehalogenator groups. The dehalogenation groups use the hydrogen intermediate as an electron donor and the different haloethenes as electron acceptors through competitive inhibition. Model simulations suggest first that the initial relative population size of dehalogenators and H(2)-utilizing methanogens greatly affects the degree of dehalogenation achieved. Second, the growth and decay of biomass from soluble carbohydrate plays a significant role in reductive dehalogenation. Finally, the carbohydrate delivery strategies used (periodic versus batch addition and the time interval between periodic addition) greatly affect the degree of dehalogenation that can be obtained with a given amount of added carbohydrate.     

钛白副产硫酸亚铁的综合利用研究

以钛白副产硫酸亚铁、氯化钾和氨水为原料，采用硫酸钾铵法制取硫酸钾。实验结果表明，该工艺生产的产品，其质量达到ZBG-21006-89国家标准，且此工艺流程简单、操作方便、条件易控制，无二次污染。     

Chlorination of dibenzofuran and dibenzo-p-dioxin vapor by copper (II) chloride

Dibenzofuran (DF) is formed from phenol and benzene in combustion gas exhaust streams prior to particle collection equipment. Subsequent chlorination at lower temperatures on particle surfaces is a potential source of chlorinated dibenzofuran (CDF). Gas streams containing 8% O₂ and approximately 0.1% DF vapor were passed through particle beds containing copper (II) chloride (0.5% Cu, mass) at temperatures ranging from 200 to 400 °C to investigate the potential for CDF formation during particle collection. Experiment duration was sufficient to provide an excess amount of DF (DF/Cu=3). The efficiency of DF chlorination by CuCl₂ and the distribution of CDF products were measured, with effects of temperature, gas velocity, and experiment duration assessed. Results of a more limited investigation of dibenzo-p-dioxin (DD) chlorination by CuCl₂ to form chlorinated DD (CDD) products are also presented.

The efficiency of DF/DD chlorination by CuCl₂ was high, both in terms of CuCl₂ utilization and DF/DD conversion. Total yields of Cl on CDF/CDD products of up to 0.5 mole Cl per mole CuCl₂ were observed between 200 and 300 °C; this suggests that nearly 100% CuCl₂ was utilized, assuming a conversion of two moles of CuCl₂ to CuCl per mole Cl added to DD/DF. In a short duration experiment (DF/Cu=0.3), nearly 100% DF adsorption and conversion to CDF was achieved. The degree of CDF chlorination was strongly dependent on gas velocity. At high gas velocity, corresponding to a gas–particle contact time of 0.3 s, mono-CDF (MCDF) yield was largest, with yields decreasing with increasing CDF chlorination. At low gas velocity, corresponding to a gas–particle contact time of 5 s, octa-CDF yield was largest. DF/DD chlorination was strongly favored at lateral sites, with the predominant CDF/CDD isomers within each homologue group those containing Cl substituents at only the 2,3,7,8 positions. At the higher temperatures and lower gas velocities studied, however, broader isomer distributions, particularly of the less CDD/CDF products, were observed, likely due to preferential destruction of the 2,3,7,8 congeners.