EVALUATION OF NATURAL ATTENUATION OF KETONE, ALCOHOL AND ETHER IN THE GROUNDWATER DOWNGRADIENT OF WEST KL AVENUE LANDFILL SITE, KALAMAZOO, MICHIGAN

Natural attenuation is a well documented process that explains the reduction of certain organic contaminants in groundwater. A combination of factors, including chemical properties and type of the contaminants, geology of the area, amount and type of bacterial population in the subsurface, and the geochemistry of the environment, act in combination to reduce the concentration of the contaminants naturally.

The West KL Avenue Landfill Site is an EPA controlled site located in Oshtemo Township, Kalamazoo County, Michigan. It is in a rural area near the crest of the Kalamazoo moraine. Most of the unconsolidated sediments in the area are glacial deposit composed of till and outwash material. There are two aquifers in the area and the upper unconfined aquifer has been contaminated by the leachate from the site. The plume in the area is bi-directional with one segment moving towards the SW and the other moving in a NW direction. The maximum extent of the plume is about 7200 feet downgradient from the landfill. An evaluation of natural attenuation is being conducted for this site. The degradation of BTEX and chlorinated organic compounds (PCB’s, TCE and DCE) have been studied more than other compounds, because these have more severe health effects. The groups ketone, alcohol and ether are much less studied, as these are less toxic and comparatively easily degradable.

An evaluation of natural attenuation of these compounds using methods of Buscheck and Alcantar (1995) and Weidemeier (1996) has been attempted in this paper. Four transects along a flowpath through the anaerobic core of the plume were analyzed to evaluate the process. Microcosm studies by the University of Waterloo showed faster aerobic biodegradation of these compounds at the site and therefore natural attenuation would be faster near the aerobic edges of the plume. The calculated natural attenuation rate constants showed decreasing trend for all the compounds along all four transects excepting THF and MEK, which showed increasing trend along three of the four transects. Another trend analysis method, the Mann-Kendall Test for nonparametric statistical analysis also tested the trend.