45 



STATEMENT OF ROBERT ENGLER, DIRECTOR, CENTER FOR CON- 

 TAMINATED SEDIMENTS, U.S. ARMY ENGINEER WATERWAYS 

 EXPERIMENT STATION, U.S. ARMY CORPS OF ENGINEERS 



Dr. Engler. Thank you, Mr. Chairman, and members of the sub- 

 committee. I am pleased to be here on behalf of the Corps Water- 

 ways Experiment Station where I am senior scientist in the envi- 

 ronmental laboratory. I will summarize my statement which has 

 been submitted for the full record. 



The Corps has been applying considerable scientific engineering 

 and management expertise to solving problems associated with con- 

 taminated sediments both in our projects and through work for 

 others. Research over the past two decades emphasizes the identifi- 

 cation, assessment, and management of contaminated sediments 

 and encompasses endangerment assessments, risk analyses, resto- 

 ration, remediation. 



Sediment research in the '70's was broad and included a basic 

 understanding of ecological impacts of management of clean as 

 well as contaminated sediment. Research, in cooperation with EPA 

 in the '80's, focused on contaminated sediments and emphasized 

 field-verified, second generation tests and further procedures for 

 identification assessment and management. Research in the '90's, 

 also in full cooperation with the EPA, focuses on highly contami- 

 nated sediments emphasizing chronic/sublethal effects as well as 

 the other treatment technologies. 



The determination that a sediment is contaminated and unsuit- 

 able for unrestricted aquatic disposal is made by application of 

 what we call effects-based testing and a preponderance of evidence 

 leading to a determination. Effects-based testing is a holistic ap- 

 proach using a combination of biological, geochemical, and physical 

 analyses. 



As requested, the following contaminated sediment treatment 

 technologies are summarized and noted in the full testimony. Suba- 

 queous capping has been demonstrated in Long Island Sound, New 

 York Bight, Duwamish Waterway, and Puget Sound, and sediment 

 remediation projects in Puget Sound. Costs for normal mainte- 

 nance dredging are around $4 to $8 a cubic yard or ton, and cap- 

 ping would double or triple these costs. 



Confined disposal facilities are engineered structures on the land, 

 partially in water, or completely in water resulting in an island. 

 They are designed to retain fine-grained sediment particles and the 

 contaminants, and costs range from about $10 to $30 per cubic 

 yard. 



After considerable testing and evaluation, wetlands may be con- 

 structed or created with marginally contaminated sediment such 

 that the contaminants do not pose an unacceptable risk. Sediments 

 unsuitable for aquatic disposal, however, would have to be effec- 

 tively kept within the constructed wetland to minimize risk. Costs 

 may range widely from hundreds to thousands of dollars per acre. 

 Capping would increase these costs. 



In situ vitrification electrically melts a waste media creating a 

 glasslike solid and has been field demonstrated for soils with 99 

 percent reduction in PCB's. Application to in-water treatment of 



