Physical Processes and Natural Attenuation Alternatives for Remediation of WhitePhosphorus Contamination, Eagle River Flats, Fort Richardson, Alaska

摘要

This report describes the results of investigations into the role of tidal flatphysical systems in the natural attenuation of white phosphorus (WP) contamination in Eagle River Flats (ERF) on Fort Richardson, Alaska. Waterfowl feeding in ponds and marshes here ingest the WP and die. These investigations found that natural attenuation and in-situ degradation of the WP could result from certain physical phenomena operating within the EFF ecosystem. Specifically, the on-going erosion and headward recession in the gullies will drain large areas of contaminated ponds in an estimated 1 to 10 years. Lowering of water levels should lead to in-situ WP degradation and natural attenuation as pond sediments dry. Annual sedimentation rates in some ponds and marshes are sufficient to bury WP in several years or more and thereby reduce the exposure to feeding waterfowl. Ice and water are also effective transporters of WP, moving it about ERF and into Eagle River and eventually into Knik Arm where its fate is unknown. Certain areas of ERF will require artificial drainage, but natural conditions can be restored following treatment. Recommendations are made for the use of natural attenuation and additional studies that are required to ensure the successful clean-up of ERF.