3003 COLBY AVE COURTYARD BY MARRIOTT 2021-03-09

I Proposed Everett Hotel Property Environmental Site Characterization and 1 Everett, Washington Remediation Recommendations I and xylenes (BTEX) by EPA Method 8021B. Because these analyses indicated that the petroleum contaminants at the site were limited to gasoline range TPH and BTEX compounds, testing conducted at the time of our June 2009 field exploration was limited to these analytes. ,iiSoil and ground water cleanup levels in Washington State are regulated under the Model Toxics Control Act (MTCA) - Chapter 173-340 WAC. The MICA regulations provide three 1 methods- for--detexm ning_cleanup_1evels. ethod A involves the use of a tabulatec["Tist o cleanu levels for a variety of common contaminants. This method is intended for routine ' imp_levels and site assessments,for unrestricted site use, and is the method selected for use 1 fads stg '� ethods B and C provide guidance for calculating_risk-based-cleanuplevelsfor unrestricted site use and industrial properties, respectively, and were not used for this study. I The testing conducted for this study indicated the presence of detectable concentrations of gasoline-range TPH and some or all of the four BTEX compounds in samples tested from I exploration borings EB-5, EB-7, and EB-l0. All three of these borings are located in the vicinity of the former fuel dispenser. Analyte concentrations in excess of the MICA Method A cleanup level were only measured samples collected from borings EB-5 and EB-7. The • I approximate aerial extent of the contaminated area, inferred from the testing data, is depicted on the "Site and Exploration Plan," Figure 2. A summary of the laboratory results for the soil samples tested is shown in the attached Table 3. Copies of the laboratory reports are included I in Appendix B. . . • Ground Water Sampling and Testing I Ground _ samples were collected from the monitoringwell completed in exploration P P P borin . EB- As previously discussed, ground water was not encountered in the other .E--- Iexplora '. s. Prior to sample collection, the well was developed and purged by hand-bailing. Approximately three casing volumes of water were purged from the well prior to sample collection. Upon completion of purging the well, which was nearly dry, the water level was Iallowed to recover for approximately 15 minutes prior to sampling. Well development, purging, and sample collection were conducted using a new dedicated, disposable, I polyethylene bailer and bailer cord for each well. The recovered ground water samples were tested for diesel- and motor-oil-range TPH by State Method NWTPH-Dx, gasoline-range TPH .. .1..___ by State Method NWTPH-Gx, and BTEX by EPA Method 8021B. I The initial samples analyses of the indicated detectable concentrations of diesel- and Y motor- oil-range TPH in the decon water sample and detectable diesel-range TPH in the ground water I sample; however, the laboratory report indicated that the chromatographic patterns produced by the analyses were not consistent with those typical for motor-oil- or diesel-range fuels. At the recommendation of the laboratory, the samples were re-tested after filtering the sample Iextracts through a silica gel column. Filtration through a silica gel column will remove polar organic compounds (e.g., those derived from natural organic substances, such as leaves, wood, etc.) that can interfere with the petroleum analyses. Re-analysis of the samples after silica gel I August 24, 2009 ASSOCIATED EARTH SCIENCES, INC. ITJP/tb-KV090168A5-Projects1200901681KVIWP Page 8