ARCHIVED REPORTS_XR0009315 - Laserfiche WebLink

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SUMMARY OF FINDINGS ' On August 20, 2002, field personnel sounded and sampled the Port's former UST Site No 3 monitoring wells MW3-1 through MW3-3 At that time, the local direction of groundwater flow was calculated at approximately South 340 West along a gradient of 0 005 foot/foot (equivalent to 5 feet of dipper 1000 feet of horizontal distance) The average depth-to-water on August 20, 2002 was 12 43 feet below the casing-tops of the three project monitoring wells ' Groundwater samples were collected from the monitoring wells on August 20, 2002 and analyzed for TPHg by EPA Modified Method 8015, and BTEX by EPA Method 8260 No free phase hydrocarbon was observed in the monitoring wells The change in groundwater gradient and direction are indicative of the influence of the Deep Water Channel,which is 1,200 feet northeast of the site ' The following is a comparison of the August 20, 2002 groundwater sample results to the previous quarter, dated May 16, 2002, ' In monitoring well MW3-1, benzene, toluene, ethylbenzene, and xylenes increased in concentration as compared to last quarter TPHg decreased in concentration as compared to ' last quarter The sample was not analyzed for MtBE In monitoring well MW3-2, TPHg, benzene, toluene, ethylbenzene, and xylenes increased Min concentration as compared to last quarter The sample was not analyzed for MtBE In monitoring well MW3-3,benzene, and toluene increased in concentration as compared to last quarter TPHg, ethylbenzene, and xylenes decreased in concentration as compared to last quarter The sample was not analyzed for MtBE CONCLUSIONS 1 RECOMMENDATIONS ' Based on a review of the analytical results of the groundwater samples of MW3-1 through MW3-3 for TPHg and BTEX, the following conclusions are presented ' • Concentrations vary with the change of groundwater gradient and elevation A survey of domestic, municipal, agricultural, industrial and other supply wells within a ' 2,000-foot radius of the site has been conducted No municipal or drinking water supply wells were identified within the 2,000-foot radius ' The following recommendations are presented for this site ' . The Port has completed twelve quarters of groundwater monitoring for this site The Port will continue to perform quarterly groundwater monitoring In December 2001,the Port implemented the field work portion of the DHS/EHD-approved ' work plan to further assess the lateral and vertical extent of petroleum hydrocarbons in soil and ust s]W gtr12 doe 9