CORRESPONDENCE_2005-2006 - Laserfiche WebLink

Home Browse Search

URS Mr. Robert McClellon October 31, 2006 Page 3 During the trench excavation activities, a steel tank was uncovered and SJCEHD was notified. The tank measured 24 inches in diameter and 4 feet in length, and was observed to be empty. Based on our observation, it is speculated that the tank was used as a heating oil tank. The tank and a portion of the soil beneath the tank were removed from the excavation and placed on and covered with plastic sheeting. The removal, transportation, and disposal of this tank and soil are being completed. SJCEHD did not allow for the remaining excavated soil to remain on site. The removal, transportation, and disposal of this soil are being completed. Quarterly Monitoring Activities On September 29, 2006, the quarterly monitoring activities were completed. These activities included groundwater sampling and measurement of landfill gas concentrations within the probes, extraction wells, and passive vent. The groundwater samples were collected from the three monitoring wells using the following procedures: • The water level was measured from each monitoring well using an electronic water level sounder. • Prior to groundwater sample collection, each well was purged using a bailer. During purging, groundwater parameters (pH, temperature, conductivity, and turbidity) were recorded on the Monitoring Well Sampling Log form (Attachment 1) at least once per well -casing volume. Purging was completed when the groundwater parameters had stabilized to within 10 percent. The purged water was placed in 55 -gallon drums pending disposal. • A groundwater sample was collected from each well, using a bailer. The groundwater samples were placed into the analytical laboratory prepared sample containers. • The groundwater samples were labeled and placed in an ice chest with ice. The samples were shipped to EMAX Analytical Laboratory in Torrance, California, under proper chain -of -custody procedures for VOC analysis by U.S. Environmental Protection Agency (EPA) Method 8260B. Since none of the VOC constituents were detected in the groundwater sample collected from monitoring well MW -1 during the previous quarter, we requested for SJCEHD approval to empty the 55 -gallon drum containing the purged water from monitoring well MW -1 during the previous quarter's activities directly onto the ground. With SJCEHD approval, this drum was emptied onto the ground prior to the start of this quarter's activities. Each gas -migration monitoring probe, each extraction well, and each passive vent was measured for methane, oxygen, and carbon dioxide using a handheld portable landfill gas monitor. These measurements were recorded in a field log book. K:\Wprocess\25532\WorldEnterprise\Quarterly Rpt\3Q06\CovLtrRpt.doc