Idachaba M A, Nyavor K, Egiebor N O, Rogers R D
Environmental Engineering Program, Department of Chemical Engineering, Tuskegee University, AL 36088, USA.
Waste Manag Res. 2001 Aug;19(4):284-91. doi: 10.1177/0734242X0101900404.
In this study the current Nuclear Regulatory Commission (NRC) protocol is used to evaluate the stability of Tuskegee cement/cobalt chloride waste form in the presence of Thiobacillus thiooxidans (T. thiooxidans). A critical examination of this protocol and identified limitations are reported also. Tuskegee cement/cobalt chloride waste forms were shown to exhibit considerable instability to microbial degradation as indicated by significant physical deterioration, and increased leaching of calcium and cobalt on exposure to T. thiooxidans. The instability was aggravated with higher levels of cobalt chloride content of the waste forms. The degradative capability of T. thiooxidans closely followed its ability to significantly decrease the pH of its environment. Inherent limitations in the NRC protocol were observed which could lead to serious result interpretation errors. The use of a T. thiooxidans culture that is significantly lower in pH in comparison to the control medium could lead to an overestimation of the degradative effect of T. thiooxidans, while the use of a culture that is substrate limited could result in an underestimation of T. thiooxidans capability.
在本研究中，采用当前核管理委员会（NRC）的方案来评估塔斯基吉水泥/氯化钴废物形态在氧化硫硫杆菌存在下的稳定性。同时还报告了对该方案的严格审查及所发现的局限性。研究表明，塔斯基吉水泥/氯化钴废物形态对微生物降解表现出相当大的不稳定性，这体现在显著的物理劣化，以及在接触氧化硫硫杆菌后钙和钴的浸出增加。随着废物形态中氯化钴含量的升高，这种不稳定性加剧。氧化硫硫杆菌的降解能力与其显著降低环境pH值的能力密切相关。研究观察到NRC方案存在固有的局限性，这可能导致严重的结果解读错误。使用pH值明显低于对照培养基的氧化硫硫杆菌培养物可能会高估氧化硫硫杆菌的降解效果，而使用受底物限制的培养物可能会低估氧化硫硫杆菌的能力。
