SITE INFORMATION AND CORRESPONDENCE_FILE 1

Home Browse Search

JRN-39-1996 13:01 PLJCaCB — SP BRY PLANNING 5102853928 P.02 .: CALIFORNIA REGIONAL WA QUALITY CONTROL BOARD '°, 4 SAN FRANCISCO BAY REGION `I 2101 wE3STER STREET,Sude 500 OAKLAND,CA 94612 Tel: (510)226-1255 FAX: (510)296.1330 395: (5101286-0404 act sheet Questlons and Answers an the "Interim Guidance on Low-Rise Petroleum Hydracarban Cl anups" roacamber ranee Livermore National iaborator/ (1f1LJ 15suetl its wn'n maximum depth to water less man so feet and no drinking ecommendations to Improve the Cleanup P,ocess for California's water wells screened in the shallow groundwater zone within 250 abng Underground Fu.l Tanks° (October 16, 19951. in response feet of Ne leak) we recommend that active remediation be replaced this report, State 'A'ater Resources ConUcl Board fxecu0ve vviih monitoring to determine if the fuel leak plume is stable. Director Walt Pettit issued an interim Quidance tetter dated Obviously Qood judgment is required in alt o!these decisions. 8, 1995, which discussed me regulatory implications of However, that report"judgment should now include knowledge provided by the conclusions and recommendations of to LNL report the From the December 8, 1995, tatter. This Fart Sheet is intended to further amplify the guidance contained in me State Board letter for fuel cleanup sites within the San "In the interim and in light of the findings and recommendations in Francisco Bay Region through the form of"Answers" to frequently Me LLVL report, we believe clealup oversight agencias should asked questions regarding implementation of the net,petroleum proceed aggressively to close lot"risk soil Only cases. For cases cleanup intehm guidance. affecting low nsk groundwater (for instance, shallow groundwater Qwhat is considered a "source"when completing source expected to come in contact with the groundwater, it is removal? unlikely that it is a significant source of pullution. A Lcaking tanks and appurtenant structures must be removed low risk groundwater sites"? or repaired. Free product or soil which contains sufficient Q What i8 meant b3' " mobile constituents (leachate,vapors, or gravity flow)to A An example of a low risk groundwater site is described in degradc groundwater quality above water quality objectives the State Board letter as a site with maximum depth to or provide a significant threat to human health or the groundwater less than 50 feet and no drinking water wells environment should be considered a source. screened in the shallow groundwater zone within 250 feet of the leak. In addition, there should be no surface water or Gasoline or diesel free product fits this definition at other sensitive habitat that may be adversely impacted by virtually all sites. Oil and grease, degraded crude oil, and the release. degraded diesel may not be soluble enough to be considered a significant source and often do not degrade Thcse criteria arc not hard and fast rules. They are meant water quality or present a significant risk to human health to recognize that shallow groundwater is rarely used as a or the environment, drinking water source, that biodegradation in most cases will stabilize a plume within Z50 feet of the leak. and that. Many factors need to be considered when delermining if a the plume will likely remediate itself duc to natural given petroleum release con3titate5 a source. biodegradation. However, if the plume is not stable, prefercutial pathways exist at the situ, or sensitive receptors Depth of the affected soil below ground surface are near the end of the plume,then the site should not be • Depth to groundwater below ground surface considered law risk. Soil type and physical properties Presence of preferential pathways (is. old wells, utility Q How do we determine if there is a significant risk to human trenches, ctc.) health at a site? Type of pettolevm released A The American Society of Testing and 24aterials (AS-1'rf) Infiltration rate standard for Risk Based Corrective: Action, ASTM E-1739- Spatial distribution of petroleum concentrations 95, (RBCA)provides look up tables for various exposure Total mass of petroleum released pathways that contains conservative screening levels (when 'fronds in monitoring data modified for California's benzene standard)for comparison Chemical and physical properties of any residual with values existing at the site. 'the standard also contains hydrocarbons a methodology for determining site specific levels that arc protective, of public health and the environment. The Good judgment must be used when weighing these and SWRCB/RWQCB is now offering two day classui for all other factors- For old releases, the absence of current interested parties in risk-basud decision making at soil and groundwater degradation often is a good indication that groundwater impacted sites. Please contact the CIC residual concentrations present in the soil are not a source of pollution. In general, if impacted soil is not in contact or ... ,.�....w,�no. Much of this information nes