Evaluation of Field Bioaccumulation as a Monitoring Tool

19. SECURITY CLASSIFICATION OF ABSTRACT 18. SECURITY CLASSIFICATION OF THIS PAGE 16. PRICE CODE 15. NUMBER OF TEXT PAGES: 40 13. ABSTRACT Laboratory methods for measuring body burdens of low-level chemical contaminants in aquatic organisms traditionally have required sizeable amounts of tissue for analysis (i.e., 10 to 30 grams wet weight of tissue per sample). Predisposal testing of dredged material and postdisposal monitoring studies therefore have focused almost exclusively on examining bioaccumulation in large benthic macrofauna. There has long been interest, however, in evaluating bioaccumulation potential in the smaller, opportunistic benthic organisms that are typically the first to colonize new dredged material deposits in high numbers. The following activities were undertaken as part of this desk-top study: 1) experts were interviewed about current analytical capabilities and costs, 2) published information on new developments in microscale analytical techniques was reviewed, 3) theoretical contaminant body burdens were calculated for representative small, opportunistic (i.e., Stage 1) benthic species from Long Island Sound (LIS) disposal sites and reference areas, which allowed estimates of required organism numbers for potential future studies, and 4) power analyses were employed to estimate the sample number required for a statistically valid comparison of tissue concentrations in Stage 1 organisms collected over DAMOS disposal mounds versus reference areas. A first-order power analysis using LIS sediment chemistry data indicates that from 5 to 20 individual tissue samples would need to be collected and analyzed to reliably detect any significant differences that might exist between a disposal mound and reference area in the body burdens of various organic contaminants. The theoretical bioaccumulation calculations presented in this report, however, suggest there would be little actual difference in tissue concentrations measured at active DAMOS disposal mounds versus reference areas. In lieu of conducting field studies to test for small differences in bioaccumulation between disposal mound and reference areas, it might be more useful to develop more advanced food chain and/or risk assessment models, with laboratory exposures and/or field collections targeted toward filling any identified data gaps. In the future, DAMOS might consider employing these microscale methods in one or more special investigative studies outside its routine monitoring efforts. Such studies could help determine, for example, whether the use of small, Stage 1 test organisms changes the outcome of field or laboratory investigations of bioaccumulation potential that have traditionally focused on larger taxa. 12b. DISTRIBUTION CODE 11. SUPPLEMENTARY NOTES Available from DAMOS Program Manager, Regulatory Division USACE-NAE, 696 Virginia Rd, Concord, MA 01742-2751 10. SPONSORING/MONITORING AGENCY REPORT NUMBER 8. PERFORMING