10 



based on the 1978 EPA/USACOE Green 

 Book. The recent publication of the 

 revised Green Book (EPA/USACOE, 

 1991) will require that these earlier 

 protocols be revisited and updated at 

 the NED. Whole sediment bioassays 

 are heavily relied upon, while 

 suspended particulate and elutriate 

 testing "may be required under certain 

 circumstances" (page 15, EPA/NED, 

 1989). As before, these "circumstances" 

 are undefined and left up to the Corps' 

 "best professional judgment"; the 

 general tendency is to err on the 

 conservative side as a safety measure. 

 The organisms acceptable as biological 

 testing species are listed in the 

 EPA/NED (1989) guidance document 

 (Appendix A). Whole sediment 

 bioassays must include 3 species from 

 3 different phyla: a crustacean, a 

 polychaete, and a bivalve, and 

 bioaccumulation testing must use the 

 survivors of the bioassay test. 



Box 1.7 



"Toxicity or Significant 

 Accumulation ? " 



Results from the laboratory 

 bioassay and bioaccumulation tests are 

 compared with results from animals in 

 control sediments (natural sediment 

 free of contaminants to confirm the 

 biological acceptability of the test 

 conditions and the health of the 

 organisms during the test) and 

 reference sediments (sediments from 

 the disposal site reference station that 

 have a similar grain size to the 

 dredged material to reflect conditions 

 that would exist in the vicinity of the 

 disposal site had no disposal taken 

 place). The bioassay tests are for acute 

 response (over 10 and 28 days 

 depending on species), not chronic 



measures. The unstated null 

 hypotheses in this box are: 



H 1: Mortalities of organisms in 



sediment from the dredging site 

 are not significantly different 

 from those in reference 

 sediment. 



H 2: Tissue contaminant levels in 



organisms in sediment from the 

 dredging site are not 

 significantly different from 

 those in reference sediment. 



Rejection of either null hypothesis 

 would place you in Box 1.8; acceptance 

 of both will lead to Box 1.9 and 

 acceptability of unconfined open-water 

 disposal. 



Underlying Assumptions: These 

 tests are based on the assumption that 

 chronic impacts are either negligible 

 or impossible to assess given the 

 present technological limitations, and 

 that any acute effects detected are due 

 to the contaminant levels and not 

 other experimental variables. The 

 COE and EPA also recognize that there 

 are more potential contaminants 

 present than could ever be tested; 

 there are at least 63,000 organics in 

 common use from a tally over a 

 decade ago (Maugh, 1978), and all 

 chemicals in sediment, biota, or water 

 cannot even be identified or quantified 

 as yet (Malins et aL, 1984). There are 

 only a few hundred standards for 

 identifying positively the thousands of 

 compounds now detectable in GC 

 profiles. Even if the technology was 

 present to identify every possible 

 chemical, the cost would be 

 prohibitive, and there would still be no 



An Integrated, Tiered Approach to Monitoring and Management of Dredged Material Disposal Sites 



