Perry Creek is a designated trout stream and a tributary of the Au Sable River, which is a designated Scenic River under the Federal Wild and Scenic Rivers Act.  Perry Creek connects with the Au Sable River approximately 2.5 miles south of the known groundwater contamination discharge area.

The DEQ investigation has revealed that the groundwater contamination is flowing into Perry Creek.  The portion of Perry Creek the groundwater plume is discharging into is surrounded by a low wet area with lush green grasses and thick shrubs full of wildlife, with no visible indication in the vegetation or in the surface water that contamination is present.  However, what is detectable to the naked eye and what can be found with sensitive laboratory equipment is entirely different.  Laboratory analysis indicates perchloroethylene (PCE), hexavalent chromium and chlorides are entering into this groundwater-fed creek.  Concentrations of PCE have been detected in the groundwater as high as 500 parts per billion (most protective state groundwater criteria is 5 parts per billion), hexavalent chromium at 7,900 ppb (most protective state groundwater criteria is 11 ppb) and chlorides at 448,000 ppb (most protective state groundwater criteria is 250,000 ppb).

However, what is detectable in the actual surface water in Perry Creek is much lower likely due to dilution.  The highest average concentration of PCE detected in Perry Creek surface water samples in the area of the groundwater contamination plume discharge is 2 ppb (lowest surface water criteria is 190 ppb based on effects to aquatic organisms), hexavalent chromium at 8 ppb (lowest surface water criteria is 11 ppb based on effects to aquatic organisms) and chloride at 18,000 ppb (there is no state surface water criteria for chloride).  While these low concentrations of contaminants are detectable in Perry Creek water, there has been no indication that aquatic life has been acutely harmed by the contaminants, although further data collection is ongoing for both aquatic insects and fish in Perry Creek.

There is no indication that the Au Sable River, located approximately 2.5 miles downstream of the known contamination discharge area in Perry Creek, has been affected by the contamination emanating from the Hoskins Manufacturing site. There has been repeated surface water sampling at the intersection of McKinley Road and Perry Creek (approx. 350 feet before Perry Creek enters the Au Sable) with no detection of contaminants from the Hoskins Manufacturing site.