Mendenhall Wetlands; Juneau, Alaska

Juneau, Alaska | 1996-Jun-08

Initial Notification: A homeowner discovered a release from his buried home heating oil tank on June 8, 1996, after an apparent tank failure. When this release actually occurred is unknown. The home and tank are 20 feet from the edge of the Mendenhall wetlands. The escaping diesel #2 contaminated a small portion of the upper intertidal zone of this marsh. The tank was last filled on May 20 and had a capacity of 500 gallons. Heavy contamination is approximately 25 by 75 feet in marsh grass, and run off continued down a narrow drainage channel to Gastineau Channel. The free product was cleaned up with sorbent pads, and the oiled vegetation and contaminated soil were removed from the site. The leaking tank was emptied and removed. The contractor hired by the potentially responsible party (PRP) recommended that any further ground disturbance or excavation would cause more harm than good and that in-situ biologically enhanced treatment should be undertaken. This treatment involved adding a garden-variety slow-release, high-nitrogen fertilizer to stimulate bacterial degradation of soil hydrocarbons and promote vascular plant regeneration, and by placing 6- to 12-inch diameter transplants from adjacent wetlands on four foot centers in the excavated area. The Unified Command, composed of the state and the USCG, approved the plan and initiated it on July 15, 1996. USCG district 17. Keyword: sorbent pads.