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' Mr.Stephen A.Johnson -3- 29 March 1994 <br /> all lead, TRPH, and TPH-diesel samples, but not for any samples analyzed for volatile <br /> constituents such as BTEX and TPH-gasoline. <br /> Quantitation limits presented for BTEX and lead are unacceptable. USEPA Method 8020 is <br /> easily able to detect and quantify levels of benzene, toluene, ethylbenzene, and xylenes <br /> above 0.5 ppb (0.0005 ppm) in ground water samples. Taste and odor thresholds for <br /> ethylbenzene and xylenes are 29 and 17 ppb, respectively, far below the 500 ppb quantitation <br /> limit proposed in your letter. It is standard practice for our underground tank investigations <br /> to require quantitation limits for BTEX at 0.5 ppb. The current federal drinking water <br /> standard for lead is 15 ppb (0.015 ppm). Therefore, your proposed quantitation limit of 50 <br /> ppb is also unacceptable. USEPA Method 239.2 has a published method detection limit of <br /> 1 ppb. Quantitation should be possible at 5 ppb. <br /> Due to the discharge of heavy hydrocarbon contaminated soils to the former waste pile, the <br /> detection of TRPH in past ground water samples, and the rationale presented above for <br /> interpretation of such measurements, TRPH by USEPA Method 418.1 should be added to the <br /> list of analytical procedures. Samples taken for TRPH samples should be in-line field <br /> filtered to remove the influence of entrained sediment. Quantitation limits for TRPH are <br /> expected to be consistent with prior analytical results submitted by Ogden. <br /> 6) Your letter appears to indicate a single round of sampling of the new well and the three <br /> existing wells will be satisfactory to be able to rule out the potential for ground water <br /> impacts from the former contaminated soil waste pile. This is also not acceptable. As I <br /> mentioned in our discussion of 23 February, strict-reading of applicable Chapter 15 <br /> regulations would require a minimum of 3 years of quarterly monitoring data—including <br /> data from a valid background monitoring well—during which time continuous compliance <br /> with the water quality protection standard has been demonstrated, before post-closure <br /> monitoring may be terminated. Since the waste pile at the Ogden facility was originally <br /> installed as part of corrective actions for an underground tank release on the immediately- <br /> adjacent property, and since the waste pile was never formally placed under waste discharge <br /> requirements, the waste pile may be interpreted to fall under language of Section 2511(d)of <br /> Chapter 15, in which case Chapter 15 requirements must be met "to the extent feasible". <br /> Feasibility is evaluated pursuant to Section 2510 (b) and (c) of Chapter 15. However, since <br /> Ogden discharged contaminated soils from sites other than the adjacent Tillie Lewis <br /> property, this interpretation is open to dispute. For these reasons, a single sampling round of <br /> the four wells cannot be interpreted to meet the intent of the Chapter 15 regulations. <br /> Please call me at (916) 255-3123 as needed to discuss this matter further. <br /> JON B. MARSHACK, D. ENV. <br /> Senior Environmental Specialist <br /> EnvironmentaUTechnical Support Unit <br /> Land Discharge Section <br />