Remediating environmental contamination by either biological or chemical methods typically results in the generation of temporary chemical intermediates as part of the process. These intermediate compounds may be related to either contaminant degradation pathways or reactions generated from the amendment itself. This article summarizes previously researched pathways and representative case studies discussing the authors' experience in generating relatively high concentrations of acetone and 2-butanone (also referred to as methyl ethyl ketone [MEK]) during both biological and chemical treatments. Experience shows that even relatively high concentrations of acetone and MEK intermediates are quickly attenuated and prove not to be a hazard outside of the treatment area. O
A series of radiological surveillance studies was conducted at Dresden hhclear Power Station by the Radiological Engineering Laboratory of the Division of Environmental Radiation which provided data on 1311 concentrations observed in the plant, the plant's effluent, and the environment. Based on the Dresden study data, an evaluation is made in this paper of the public health significance of1311 discharges from BM'R nuclear power plants. The in-plant barriers to the transport of 1311 through a BWR nuclear power plant to the site environs were found to function at a high efriciency. As a result, the critical phase of the environmental surveillance program for Dresden, a BWR without gaseous holdup, was concluded to be the sulimersion dose from noble gases, not 1311 in milk. For a BWR nuclear power plant employing gaseous holdup, it was concluded that the ingestion 1311 dose may be more limiting than the submersion dose from noble gases.
Enhanced reductive bioremediation (ERB) of halogenated organics has become widely accepted and implemented to reduce risks to human health and the environment posed by these compounds.The family of chlorinated ethenes (e.g., trichloroethene) is among the most common contaminants treated using ERB techniques. The number of microbial species able to fully dechlorinate ethenes is small, and many times their population numbers are low. As a result, many ERB practitioners have turned to the injection of designer bacteria within treatment zones as a means to accelerate the process. Otherwise, many remediation projects encounter "cis-stall," or the accumulation of the cis-1,2-dichloroethene and vinyl chloride intermediates. This article discusses three unique case studies where the addition of a balanced macro-and micro-nutrient source substantially accelerated the chlorinated ethene ERB process, independent of the electron-donor substrate applied. O
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