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

The West KL Avenue Landfill Site is an USEPA Superfund site in Oshtemo Township, Kalamazoo County, Michigan. It is located in a rural area near the crest of the Kalamazoo moraine. The bi-directional plume extends more than 7200 feet downgradient towards the SW and NW from the landfill. An evaluation of the natural attenuation is being conducted for this site. The degradation of BTEX and chlorinated organic compounds (PCB’s and TCE, 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 are comparatively easily degradable.

An evaluation of natural attenuation of these compounds along a flowpath at the anaerobic core of the plume has been attempted in this paper by using the methods of Buscheck and Alcantar (1995) and Weidemeier (1996). University of Waterloo microcosm studies 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 Mann-Kendall Test for nonparametric statistical analysis also tested the trend.