THERMAL REMEDIATION

热修复可用于处理在超级基金站点发现的危险废物。这些场所可能含有氯代烃和有毒重金属。这些材料的热处理会将有害的副产品释放到环境中。该项目旨在确定氯化副产品或金属的排放对人类人口造成的风险。最感兴趣的氯化化合物是二恶英。将在风洞实验中研究废物和空气的混合速度对二恶英形成的影响。副产品的样本将被收集，以便稍后与毒理学项目一起进行分析，以确定是否存在二恶英。这些金属的焦点将被收集起来，以便以后与毒理学项目一起进行分析，以确定是否存在二恶英。金属研究的重点将放在铬上。铬是一种不挥发的金属，在高温系统中往往会形成超细的气溶胶。六价铬具有很强的毒性，其他价态无毒。因此，重要的是能够预测铬排放的状态，并设计系统以最大限度地减少六价形式的形成。这需要了解燃烧系统中铬的氧化动力学。将建造一个低压燃烧器，在简单的层流预混合火焰中进行实验，火焰中加入了铬。在线飞行时间质谱仪将提供铬中间体的测量。这一结果将用于调整铬氧化动力学模型，以应用于实际系统的设计。与科罗拉多博尔德大学的合作将允许对活性中间体进行激光诱导荧光测量。还将对铬气溶胶的动力学进行建模，以预测气溶胶颗粒的大小。这些颗粒物的毒性可能会随着它们在大气中的老化而改变。室内人工老化将被用来模拟颗粒物在大气中的反应，在它们进入人类群体的过程中。老化颗粒物的毒性将通过分析化学以及可在整个超级基金计划中使用的各种生物分析方法进行研究。老化颗粒物的毒性将在体外以及在动物暴露于人工调节燃烧产生的气溶胶的情况下进行评估。

Thermal remediation can be used to treat hazardous wastes found at Superfund sites. These sites can incorporate chlorinated hydrocarbons and heavy toxic metals. The thermal treatment of these materials can release hazardous byproducts into the environment. This project seeks to determine the risk to human populations as a result of a release of chlorinated by-products or metals. The chlorinated compounds of most interest are the dioxins. The impact of the rate of mixing of waste and air on the formation of dioxins will be studied in a wind tunnel experiment. Samples of by-products will be collected for later analysis with the toxicology projects for the presence of dioxins. The focus of the metals will be collected for later analysis with the toxicology projects for the presence of dioxins. The focus of the metals research will be on chromium. Chromium is a non volatile metal that tends to form an ultrafine aerosol in high temperature systems. The hexavalent form of chromium is very toxic; the other valence states are not toxic. Hence, it is important to be able to predict the state of chromium emissions and to design systems to minimize the formation of the hexavalent form. This requires knowledge of the kinetics of chromium oxidation in combustion systems. A low pressure burner will be constructed to undertake experiments in a simple, laminar pre-mixed flame that is seeded with chromium. An on-line time of flight mass spectrometer will provide measurement of chromium intermediates. The results will be used to tune a kinetic model of chromium oxidation for application in the design of practical systems. Collaboration with the University of Colorado Boulder will permit laser induced fluorescence measurements of reactive intermediates to be undertaken. Modeling of the dynamics of the chromium aerosol will also be undertaken to predict the size of the aerosol particles. The toxicity of the particles may change as they age in the atmosphere. Artificial aging in a chamber will be used to simulate the reaction of particles in the atmosphere, on their way to human populations. The toxicity of the aged particles will be studied by analytical chemistry as well as by the various bioassays that are available to use throughout the Superfund program. The toxicity of the aged particles will be assessed in vitro, as well as in vivo with animal exposures to artificially condition combustion generated aerosols.