This study is concerned with one small but important part of the Comprehensive Environmental Response, Compensation, and Liability Act (the CERCLA process). It involves learning about the food, habitat, life, and habits of some small mammal species of deciduous forest and grassland ecosystems, how they affect the ecosystem under natural conditions, how they are affected by chemical contaminants, and incorporating this knowledge into ecological modeling efforts at contaminated sites. I will be identifying potential effects that toxic chemicals have on a general contaminated site based on the nature of the contaminant and the use of research results from small mammal studies. The information can be sued to evaluate an existing site to determine what the possible effects of a contaminant are to that site, small mammals at that site, and the entire ecosystem in general.