ARCHIVED REPORTS_XR0012715 - Laserfiche WebLink

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ftunt�t!arrttil.. Thr T. IME Moro not Include ou:,h information AN the detection limits at which other cornpoundu 4jai•e+ Pint detf'rt+-al. 71,t? full tnv-t Of thr lAt-ornlora rrr4,rt will bf round in !if!ction Four of thin repert. GFtitrltAt. Al.)V1SORY ON POSITIVE ft F: LILTS Though nur firm sp-CriollZeN in sampling, monitoring anti doc+.imrntasion, rather than interpretation and remadiatlon, we have been asked by thl e,ntineering lktaff fir the fteglonal Water quality Control floord to Include In our report* an advisory aaction oettlining the general typm of additional ar,tionr which may be required wrhan cont.nminntlon Is found. This advisory iR not intended to characterize conditions at this particular cite or roplacn thv services of n consulting firm specializing In the Investigation, characterization and remediation of such conditions us may exist, Rather, It it Intended to e+dvise you that swich additional actions may be required even though some time may etapee before you are contacted by one of the lntnrejavd regulutdry agent{e s. In Region 1 (which to regulated by the Son Francisco Hcgioniil tater Quality Control board,} the thresholds aro readily defined In the lloorkl`s publication, PaLdjll—n—ea far 60dra� +� Fu_Sj LftS.lift. According to this document, molt which has less than loo parts per million total petroleum fuel hydrocarbon (TPII) contiAmination d,:�qs not generally require immediate additional action. Board engineers rmphosize that thin dors not mean thot steins action might not be required In the future. Still, the site Is ansignerd a law priority unless it is situated In an area of high hydtvSt-ologic concern. The detection or more thnn 1013 ppm TPH In the native soil hcnemh a tank Is gfenerally considered grounds for requiring an additional Investigation in the Corm of soil borings and InaWlation of at least one groundwater monitoring well followed by periodic monitoring. The detection of 10W ppm TPH is usually viewed by the Board as an unacceptable level or fuel saturatic"t which will mandate excavbtiOn of the effected ground down to the furthest practicable reach of conventional excavating machine�I followed by soil Wrings trod installation of groundwater monitoring tither regions use different standards for determining when n groundwater investigation will be required. For example benzene is nftnu ui.f:d in lieu of TPIT. Even very low levels of benzene are often seen as ground% for requiring a subsurface Investigation. This crIterir may be relaxed or atifraned depending on the location of the a systetns, the depth to water. typeotf aoil�a dotter car`Gfentrnti ntiuridnr watbenetfsne involved, The above standards apply only to funib. when sampler taken in connectlen with Awaste oil tank or b s,rtvearet tank are found to cunt_�in even small EPA.-pricrity--i►ol.lutant,c -til+ich as 'Ct_:_E* Pc:B, OCI� etc. which are detected by EPA mothOds 010, 130201 -- jitnndards are often applied. let these eases, soil borings and monitoring wt:11 installation may be raquirnd it there is any detectable amount of any Or :5hispling Hepnrt "05'f-t:.-1 Chevron 19113 SECTION �pJpesga 112