Agenda - Council - 10/14/1980 - Laserfiche WebLink

Home

INVESTIGATION EXTE~F OF G~S MIGRATION The extent of gas migration w~s investigated by sampling soil gases on a series of transects aw~y frc~ the landfill. Holes one-inch in diameter and one to three feet deep were bored and inmediately plugged with rubber stoppers. The soil g~ses were analyzed for combustible gases, oxygen, hydrogen sulfide, and carbon dioxide. Gas samples were also oollected into aluminized mylar or TedlarR bags for gas chromatographic analysis. Figure 2 shows the sampling locations and Table 3 su~,[mrizes the results. Fr~n the data collected on August 24, 1980 it appears that the landfill gases on the north side which are not controlled have migrated to a distance of about 50 feet from the landfill property line. It appears %hat-'the collection system on the west side-of the landfill is effectively prevent- img the migration of landfill gas into the backyards of the residences.- Gas samples taken at one-to-three foot depths close to the landfill were ctknrac~erized by high ooncenhrations~of~nnethane (greater than the lower explosive limit of 5 percent), high concentrations of 002 (about 40 percent), and low concentrations of escygen (<5 percent). Soils from these borings generally had a putrid odor that was ._strongest closest to the landfill. An att~npt was made to analyze for_ hydrogen 'sulfide~.using~detector tubes (detectable limit of .0.1 pt~n) burp.none was detected.-~ The-se soils~did not appear to have a sulfide odor which is easily detected by its characteristic odor. Soil gas samples taken along the boundary of the landfill and between the residences and the landfill had a high oxygen content, low carbon dioxide oontent, and combustible gases were not detected. All of these soil borings except two smelled clean; that is, the putrid odor ~as absent. Two samples did have a slight odor; ~owever, combustible gases were not detected in the sampling boles. It does not appear that the concentrations of combustible gas measured in the soils behind the hom~s presents a serious health or safety hazard. However, because there is'a potential for gas migration into the hc~es, sbort-term and long-term surveillance and abatement programs st~uld be and are being pursued (Appendix F).