The report involves a study to see if periphyton would make a good indicator species for water quality. The testing was done in the Asa Creek-Kaskaskia River system, Moultrie County, Illinois. Intrastation correlations among eight parameters measured during a periphyton acrual study at these stations revealed that the discharge of effluent into Asa Creek coupled with Asa Creek's low stream order resulted in not only a wide flux of physico-chemical conditions, but had a varied effect on the periphyton. Bacterial uptake kinetics experiments demonstrated that the periphyton at stations influenced by the wastewater treatment plant effluent assimilated two to three times more dissolved organic matter than at stations not influenced by the effluent. This reinforced the premise that the attached community was the most sensitive to subtle changes in the aquatic environment. (Author)