ARCHIVED REPORTS XR0003547 - Laserfiche WebLink

Home Browse Search

C A M B R A From March through June 1999, weekly groundwater extraction (GWE) was performed on well RW-lA From July 1999 to June 2000, GWE occurred bi-monthly Beginning June 2000 the GWE occurred weekly During each GWE event, approximately 5,000 gallons of water is purged by a vacuum truck and transported to the Martinez Refining Company for recycling On August 22, 2000 a pump was installed in RW-1 A, which pumped into a Baker tank A vacuum truck emptied the tank and recycled the water as described above During mid-March 2001, the Baker tank was removed and since then a vacuum truck has been used to extract groundwater directly from RW-lA on a bi-weekly basis As of May 8, 2001, approximately 530,167 gallons of water have been removed from RW-lA As shown on Table 2, based on the concentration data, groundwater extraction has effectively removed approximately 351 pounds of TPHg, 49 pounds of benzene, and 566 pounds of MTBE ANTICIPATED THIRD QUARTER 2001 ACTIVITIES Blaine will gauge and sample the site wells according to the existing sampling schedule and tabulate the data Cambria will prepare a groundwater monitoring report We anticipate completing construction of the permanent groundwater extraction system and starting it up in . July 2001 CONCLUSIONS AND RECOMMENDATIONS The petroleum hydrocarbon and MTBE concentrations in groundwater samples collected from the shallow wells this quarter are within the historical norm for this site Wells MW-5, MW-8, and RW-1A continue to contain the highest levels of hydrocarbons and MTBE However, analytical data from offsite wells suggests the hydrocarbons and MTBE detected in onsite wells are remaining onsite Groundwater samples from the Caltrans well contained low levels of toluene, ethylbenzene and xylenes, which it has contained in the past MTBE (by EPA Method 8020) was reported in the CalTrans well sample this quarter at a concentration of 2 88 ppb The EPA Method 8260 analysis for MTBE on the same groundwater sample did not detect MTBE This suggests that the detection of MTBE may be anomalous Sample Frequency Reduction Cambria proposed sampling frequency reductions in the previous quarterly monitoring report for . some of the wells associated with this site We proposed sampling the domestic wells annually 0783 2