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California Rtional Water Quality dintrol Board <br /> Central Valley Region `.W.,. ;t <br /> R <br /> Peter M.Rooney Sacramento Main Office - <br /> J. Schnabel <br /> Secretaryfor Internet Address: httpJ/www.swrcb.ca.gov/-xwgc65/home.html Chair <br /> Environmental 3443 Routier Road,Suite A,Sa¢ mto,California 95827-3003 <br /> Protection Phone(916)255-3000•FAX(916)255-3015: <br /> 8 March 1999 <br /> 1 <br /> Ms. Katie Hower <br /> Chevron Pipe Line Company <br /> 4000 Executive Parkway, Suite 400 <br /> San Ramon, CA 94583 <br /> RESPONSE TO COMMENTS ON SITE STATUS REVIEW, FORMER LYOTH LOADING <br /> STATION, CHEVRON PIPE LINE, TRACY, SAN JOAQUIN COUNTY <br /> I have reviewed Geomatrix's 11 January 1999 response to my comments on various investigation and <br /> monitoring reports for Chevron Pipe Line Company's (CPL) former Lyoth Loading Station in Tracy. <br /> Geomatrix's response does not adequately address the issues presented below. The italicized paragraphs <br /> reprint my original comments to which Geomatrix responded to. <br /> 1. The vertical extent of soil contamination at the following locations is undefined: B-9, B-16, B-21, <br /> GP-3, and MW-2. .Due to the inconsistency in sampling, other locations may also lack definition. <br /> The lateral extent of crude oil soil contamination at GP-3 is defined, but not for contamination by <br /> total petroleum hydrocarbons as (TPHd) and polynuclear aromatic hydrocarbons (PAHs). The <br /> lateral extent of crude oil, 7PHd, and PAH soil contamination at GP-9 and GP-10 needs <br /> definition. <br /> Geomatrix states, "The lateral and vertical extent of petroleum hydrocarbon affected soil has been <br /> assessed to the extent necessary to make decisions regarding the evaluation of potential health risks <br /> from petroleum affected soil and impact to groundwater quality at the site." However, since the <br /> vertical extent of soil contamination at B-9, B-16, B-21, GP-3, and MW-2 has not been defined, <br /> Geomatrix should explain how threats to groundwater quality can be fully assessed. I concur that <br /> TPHd is a hydrocarbon range encompassed within the TPH measured as crude oil(TPHc). TPH as <br /> gasoline and P_AHs also are hydrocarbon ranges in TPHe. However, the absence of TPHc does not <br /> necessarily mean that TPHd, TPHg, and PNAs are not present. TPHd and some PAHs will not be <br /> detected if TPHc is analyzed using purge and trap. On the other hand, TPHg and volatile PAHs <br /> will not be detected if TPHc is analyzed using extraction methods. TPHc will cover the range of <br /> hydrocarbons if it is analyzed using both extraction and purge and trap methods. Geomatrix should <br /> clarify if the TPHc; analyses used both of those methods. Geomatrix states that TPHd is not present <br /> at the site. However, TPHd was detected at MW-2 at 15 and 25 feet bgs at 16,000 mg/kg and <br /> 1,600 mg/kg, respectively. Geomatrix should explain this apparent discrepancy. <br /> California Environmental Protection Agency <br /> p�Recycled Paper <br />