Laserfiche WebLink
• GROUNDWATER SAMPLE COLLECTION <br /> Groundwater samples were collected from each of the groundwater wells (TBI, MW3R, MW4, <br /> MW5, MW6, TB7, TB8 and TB10), by EMC personnel on May 14, 1996 Prior to sample <br /> collection, at least three well volumes of groundwater were removed from each well using a portable <br /> submersible pump or bailer All equipment was cleaned using a solution of Alconox and water <br /> followed by two tap water rinses The actual groundwater samples were collected with disposable <br /> PVC bailers equipped with bottom emptying devices A new bailer was used for each sample <br /> collected Samples were transferred into the laboratory supplied 40 ml VOA vials pending analyses <br /> The chain-of-custody documentation is presented in Appendix B <br /> ANALYTICAL DATA <br /> Each groundwater sample was transported on ice in a hght-proof chest to American Analytics The <br /> samples were analyzed for total hydrocarbons (TPHg) and volatile aromatic compounds(BTEX) by <br /> EPA methods 8015 and 8020, respectively Table 1 presents a summary of the TPHg and BTEX <br /> data The complete laboratory reports for the current samples are included in Appendix B <br /> The current results indicate the presence of TPHg in all wells sampled (ranging from 0 17 mg/L to <br /> 69 mg/L) Benzene concentrations ranged from 3 7 to 20,000 ug/L with the highest concentrations <br /> noted m well TB-7 An interpretation of the dissolved hydrocarbon plume is shown on Figure 2 <br /> CLOSING <br />• Based on the recent site investigation and monitoring program, it appears that the groundwater <br /> beneath the site is impacted with high concentrations of dissolved phase hydrocarbons Although the <br /> groundwater elevation has fluctuated, the historical monitoring events suggest that the flow direction <br /> of groundwater across the site is generally to the east-northeast Thrifty will continue to monitor the <br /> on-site wells on a quarterly basis <br /> If you have any questions, please contact Mr Ray Freidnchsen at (310) 923-9876 <br /> Very truly yours, <br /> Peter D'Amico <br /> Manager Environmental Affairs <br /> cc CVRWQCB, Elizabeth Thayer <br />