Agenda - 11-03-2004-9c - Laserfiche WebLink

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a~ Orange County Trigon Project No 036-00-OIGB Hillsborou h Landfill Site 7uly 24, 2000 When the methane gas was encountered during drilling, the augers were charged with water to displace the gas for safety purposes.. Trigon observed no stressed vegetation on the landfill surface that is an indication of substantial gas migration through the landfill material to the ground surface and atmosphere.. 4.0 CONCLUSIONS AND RECOMMENDATIONS • Based on the geotechnical borings advanced across the property, a ]andfilled area of approximately ten acres was found to contain refuse and deb*.is • No soil contamination, with the possible exception of arsenic, was detected at concentrations above Remediation Goals established by the NC DENR. • Arsenic was measured in soil at an average concentration of 9.5 mg/!cg and ranged from 23 to 19.7 mg/kg- It was also detected in a background sample at a similaz concentration of 10..5 mg/kg, While above the NC DENR Remediation Goal of 4.6 mg/kg, these concentrations fall within the range that the LT..S. EPA considers "average and common" (USEPA, Office of Solid Waste and Emergency response, EPA/540/S-9G/500, December 1995). • No groundwater contamination exceeded the NC DENR standards established to be protective in situations where groundwater is not used as a source of drinking water. And, with the exception of chlotobenzene and lead, no contaminants were present above North Carolina's stringent drinking water standards. • The landfilled area at the site have the potential to generate methane and other landfill gases, bttt not at rates subject to federal regulations that would require it to be collected and treated. However, future construction and other site improvements in and around landfill need to take into account the potential for landfill gas generation and the hazards that it may pose. TRlGGNENCINEEItrNG CONSULT.INTS, INC. Page 8