REPORT DOCUMENTATION PAGE

Form Approved

REPORT DOCUMENTATION PAGE

OMB No. 0704-0188

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1. AGENCY USE ONLY (Leave blank)

2. REPORT DATE

3. REPORT TYPE AND DATES COVERED

December 1998

Final report

4. TITLE AND SUBTITLE

5. FUNDING NUMBERS

Improving Dredged Material Management Decisions with Uncertainty Analysis

WU 33182

6. AUTHOR(S)

Donna J. Vorhees, Susan B. Kane Driscoll, Katherine von Stackelberg,

Todd S. Bridges

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

8. PERFORMING ORGANIZATION

Menzie-Cura and Associates, Inc.

REPORT NUMBER

One Courthouse Lane, Suite Two, Chelmsford, MA 01824;

Technical Report DOER-3

U.S. Army Engineer Waterways Experiment Station

3909 Halls Ferry Road, Vicksburg, MS 39180-6199

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

U.S. Army Corps of Engineers

Washington, DC 20314-1000

11. SUPPLEMENTARY NOTES

Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.

12a. DISTRIBUTION/AVAILABILITY STATEMENT

12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited.

13. ABSTRACT (Maximum 200 words)

Uncertainty regarding the ecological and human health risks associated with dredged material disposal alternatives

can lead to delayed, costly and unwise decisions. Uncertainty about the likelihood for unacceptable impacts can result

from the lack of knowledge about critical elements or processes contributing to risk or natural variability in the same

elements or processes. The objectives of this effort were to (a) describe in detail the uncertainty sources within the

tiered evaluation process, (b) rank sources of uncertainty within the tiered evaluation process by degree of contribution,

and (c) make preliminary recommendations for further refinement of the ranking. The most significant sources of un-

certainty within the tiered evaluation process included identification of the contaminants of concern, the selection and

use of reference sediments, trophic transfer of sediment-associated contaminants, the potential for chronic toxicity and

the use of chronic sublethal bioassays, defining assessment and measurement end points during the conduct of an envi-

ronmental risk assessment, the use of contaminant fate and transport models, tissue-based measures of toxicity, dose-re-

sponse models for human receptors, and the toxicity of complex mixtures. Specific recommendations for the need for

more extensive field validation for many of the components in the tiered evaluation process were made.

14. SUBJECT TERMS

15. NUMBER OF PAGES

Contaminated sediment

Risk assessment

Dredged material

Uncertainty

16. PRICE CODE

17. SECURITY CLASSIFICATION

18. SECURITY CLASSIFICATION

19. SECURITY CLASSIFICATION

20. LIMITATION OF ABSTRACT

OF REPORT

OF THIS PAGE

OF ABSTRACT

UNCLASSIFIED

Standard Form 298 (Rev. 2-89)

NSN 7540-01-280-5500

Prescribed by ANSI Std. Z39-18

298-102