Mr. O’Gara has written a report (December 22, 2003) on the site investigation and removal that has taken place so far.
The wet season has returned and the spot on the river bank where gasoline was seeping is now underwater. Mr. O’Gara reports there is no visible sheen.
The ground water collection system is in place and operating. Mr. Hofenbredl continues to pump water from the sumps into a tank to sparge.
The sparging system is working very effectively, reducing contaminant levels significantly below required treatment levels. To achieve this, Mr. Hofenbredl replaced the 6,000 gallon Baker tank with a 10,000 gallon rectangular open-top tank allowing for more effective sparging. He also installed charcoal canisters to further polish the sparged water before discharge.
After sparging, the initial water that was collected using the ground water collection system was sampled on December 17. Laboratory analysis showed that it contained less than 0.1 milligram per liter (mg/l) total petroleum hydrocarbon (TPH) and 0.59 microgram per liter (ug/l) benzene. The Water Pollution Control Facilities permit from Oregon’s Department of Environmental Quality allows the land application of the sparged water once the TPH has been reduced to below 10 mg/l. Not only was the TPH level a hundred fold below the permit level, but the benzene level was almost ten fold below 5 ug/l, the maximum concentration level (MCL) for benzene in drinking water.
Four monitoring wells were sampled on 12/30/03. Specialty Analytical Laboratories used EPA Method 8021 to analyze for gasoline components. Laboratory results show benzene levels still very high, ranging from 2920 ug/l to 33,800 ug/l. As reference, we have set the cleanup level at 5 ug/l the MCL for benzene in drinking water.
Continued pumping, sparging, and discharging.
Samples will be drawn from the monitoring wells in late March
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