ARCHIVED REPORTS XR0000932 - Laserfiche WebLink

Home Browse Search

Isampler, vertically to depths of 60 feet bsg. • I Grab ground water samples were collected from each probe boring using a Geoprobe hydropunch sampling assembly. The probe rods were advanced to approximately 60 feet bsg. TPH-g was detected in the water samples collected from B8 and B9 at concentrations of 71 micrograms per liter (µg11) and 88 µg/1, respectively. TPH-d was detected in the water sample collected from B9 at a concentration of 140 µg/1. Ethylbenzene and total xylenes were detected in ' the sample from B8 at concentrations of 1.2 µg/1 and 1.3 µg/1, respectively. Toluene, ethylbenzene and total xylenes were detected in the water sample collected from boring B9 at concentrations of 0.62µg11,0.72 gg/I and 4.3 µg/1,respectively.No other analytes were detected at or above laboratory reporting limits in the grab ground water samples analyzed. ADDITIONAL SUBSURFACE INVESTIGATION In October 2002,four 8.25-inch soil borings were advanced at the site,to be completed at monitoring wells MW-7 through MW-10. Soil samples were collected from monitoring well pilot borings at five-foot intervals, beginning at 5 feet bsg. IBorings MW7 through MW 10 were completed as ground water monitoring wells to further assess the downgradient lateral and vertical extent of impacted soil and ground water. A total of eight soil liesamples were collected and analyzed for TPH-g, BTEX, EDB, 1,2-DCA and the suite of five fuel additives, including MTBE.No analytes were detected at or above laboratory reporting limits in the soil sample analysis. SITE STRATIGRAPHY A mottled ale brown and red-brown stiff,clayey silt/silt clay was encountered from surfacegrade �p Y Y Y Y � to depths of approximately 5 feet bsg in each boring. A pale to dark gray-green,silty,medium dense, Ipoorly sorted fine sand was generally encountered from 5 feet to 10 feet bsg. A pale brown to pale gray, stiff, silty clay was encountered from 10 feet to 20 feet bsg. A pale brown, medium dense, poorly sorted, silty fine sand was generally encountered at depths between 20 feet and 25 feet bsg. A dark brown, very stiff, silty clay was encountered at depths greater than 25 feet bsg. Contamination detected in MW-I may be moving differently than that detected in MW-2 and MW-3 due to different sand bodies contributing to the wells. Silty sand was encountered at 10 feet bsg in MW5 and MW6 and at 20 feet bsg in MW6 and B7. Silty clay was encountered at 5 feet and 15 feet through 30 feet bsg in MW5 and at 5 feet, 15 feet, I 25 feet, and,30 feet in MW6. Silty clay was also encountered at 5 feet through 15 feet, 25 feet, and 30 feet in boring B7. The sand at 10 feet bsg appears to have a north-northeast to south-southwest I orientation;the sand at 20 feet bsg appears to have a east-northeast to west-southwest orientation and limited lateral extent. Advanced GeoEnvironmental,Inc. I