ARCHIVED REPORTS_XR0009415 - Laserfiche WebLink

Home Browse Search

rFRCM I' Panasonic ANS/PAX PHONE NO. Sep. 28 1998 01 18AM P92 r • rMr S€Il Little (AGE) Curtiss Pontiac December 8, 1999 r Page 3 r COMMEM7' rPhysicochemicaily, most parameters for the sods tested are within the range for microbial growth and biodegradative activity; however, the pH is relatively alkaline, and may be r contributing to lower general and selective microbial enumeration data observed for most samples Sample MW7-5 had especially low values for microbial recoveries and may reflect some localized biotoxicity Lower biodegrader counts were encountered for those samples ' tested at the nigher (5000 ppm) contaminant concentration, suggesting that this material may also be exerting some limited ototoxicity (this is frequently found for gasoline-impactod soils where the solvent-like nature of the constituents can adversely effect microbial cell integrity, ' although usually not until the 7,500 ppm level). In summary, there is evidence that natural bioattenuation is occurring for the majority of sods tested, albeit at relatively low levels. There is a sufficiency of bionutrients to support continued activity for some time, although periodic monitoring is recommended in order to ensure that concentrations remain at appropriate levels It is suggested that efforts be taken to daterm€ne whether and to what degree biotoxicity may be present at the site (such as high salt concentrations, heavy metals, other solvents, etc.). A gradual lowering of pH to more neutral levels will likely have a beneficial effect on microbial population dynamics and activity Should you have any questions concerning these results, please do not hesitate to contact me r AKK.em I I f • I