Presentation Description
New Developments in Assessment and Management of MGP Contaminated Sediments
Recent research and demonstration efforts have led to improvements in our ability to effectively assess and manage sediments contaminated with manufactured gas plant (MGP) wastes. Active capping, in which a sediment cap is designed to serve as a permeable reactive or adsorptive barrier, can be an effective tool for managing contaminated sediments. In this presentation, the current status and prospects for increased use of active capping for MGP sites will be discussed, including the effectiveness and limitations of existing approaches. Current research to expand the options and/or improve the effectiveness of existing approaches will be described. Appropriate technologies will be identified for particular contamination situations. Of particular interest is the use of organo-modified clays which can be effective in the presence of both dissolved and separate phase MGP contaminants. The ability of these materials to manage contaminants moving with a nonaqueous phase liquid, with upwelling groundwater, or as a result of gas ebullition will be evaluated both on the basis of laboratory studies and field demonstrations. In addition, passive sampling of interstitial waters via an in-situ profiling solid phase microextraction (SPME) approach is used to assess bioavailability and the rate and mechanism of mobility of MGP contaminants. This sampling approach is also used to help understand the field performance of the capping technologies.