ARCHIVED REPORTS_XR0004514 - Laserfiche WebLink

Home Browse Search

A R I Ms. Margaret Lagorio �'1� • February 1, 2001 Changes in Sampling and Analytical Frequency: Cambria proposes changing the scope of work, sampling and analyses for the site as follows: 1. Cambria will monitor the remediation system on a bi-weekly rather than weekly basis. The system has the capability of notifying Cambria through a telephone autodialer in the event of a system shutdown. System effluent samples will be collected on a bi-weekly basis, and a full set of system samples will be collected monthly. These changes are appropriate because the remediation system is operating reliably and no analytes have been detected past the first carbon vessel in the four months since August 2000, 2. The analytical scope for the monitoring well and remediation system samples will be reduced to TPHg, BTEX and MTBE by EPA Method 8020 and MTBE by EPA Method 8260. These changes in analytical scope are appropriate for the following reasons: (a) The only fuel oxygenate other than MTBE and methanol that has been detected during monitoring well sampling was 44 parts per billion (ppb) TAME from MW-1 . on April 28, 1998. (b) Methanol was last detected in a sample from well EW-1 on January 20, 2000 and had previously been detected in samples from other monitoring wells. However, methanol is a common laboratory contaminant and its detection in samples from the site is believed to be the result of laboratory processes. (c) The only time that any fuel oxygenates other than MTBE were detected in samples from the remediation system was on September 22, 2000, when the system was restarted after a shutdown due to a carbon changeout. TBA and ethanol were detected at 82 ppb and 100 ppb, respectively. These detections are very near the detection limits for the analytes and likely originated from the remediation process. 3