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Roseviile Pubiic Schoois 51'S Project #94941- YF May 18, 1990 Page 3 Conclusions The only evidence for fuel oil impacts encountered in this exploration at the Lexington School site were minor olfactory detection and PID meter readings slightly exceeding back- ground levels. Soil chemical analysis peIformed on two samples obtained from the boring indicate no petroleum impacts exceeding target detection limits for benzene, ethylbenzene. toluene and xylene (BETX) or total petroleum hydrocarbons (TPH) as fuel oil. Olfactory detection of fuel oil odors was not encountered below 8 feet. Groundwater at the site is estimated to be at approxima!ely 20 feet below the ground suIface based on data from other STS soil borings performed in the area. A silty clay layer encountered between 6 and 9 feet is likely to provide a barrier between the groundwater and any impacts resulting from the previously existing tank. . Recommendations Soil impacts at the site resulting from the previously existing fuel oil tank appear to be minor and limited in vertical extent, based upon the data obtained in this site explora- tion. STS therefore recommends MPCA closure of the Lexington School site in Roseville. Minnesota. General Qualifications The analysis and conclusions included in this report are based upon data from one hand auger soil boring, two soil chemical analyses and the Tank Removal Documentation Report dated December 18, 1989 (STS Project No. 94933-XF). Variations in soil classification and contaminant content may occur in areas in which borings were not peIformed. the nature and extent of which may not become evident without further exploration. Any inferred infor- mation around the boring is based upon extrapolation from the soil boring data only. This report was prepared using currently accepted engineering and geological practices to assist the client in the evaluation of the property. No other warranty, expressed or implied, is made. Our scope of this project is limited to the specific project and loca- tions described herein. Our description of the project represents our understanding of the site conditions at the time we peIformed our services. STS is pleased to have been of service to you on this project. If you have any questions regarding the work performed at Lexington School, please contact us at 559-1900. Sincerely, STS CONSULTANTS. LTD. /;./ ~// J ~"-'::<" ;/7/ // / d" . / . ';7,/L'/c / (,... ~.{-c~ -./ _.A.. /' /' / - Loren M. Hubert Environmental Geologist ~ Robert L. DeGroot. P.E. Principal Engineer LMH/dj Encs.