12 



open-water disposal (Box 1.9) or re- 

 evaluate the permit for special 

 management decisions (Box 1.8). 

 Even though one can argue that 

 best professional judgment is still a 

 subjective interpretation, it is 

 important to keep in mind that it 

 would not be the subjective 

 interpretation of one person 

 operating in a vacuum; a reviewer 

 would be operating within a 

 framework of experience within 

 their agency as well as having 

 access to the historical data 

 gathered by the DAMOS program. 



Given our present state of 

 knowledge, it is unlikely that many of 

 the issues identified above will be 

 resolved in the short term. Because of 

 the many sources of uncertainty, the 

 general tendency is once again to "err 

 on the conservative side"; the tendency 

 in the past has been to proceed to the 

 options in Box 1.8 if either of the null 

 hypotheses are rejected. 



Box 1.8 "Special Management" 



One arrives at this box either by 

 having contaminated sediment (as 

 determined by bulk sediment analyses) 

 and electing not to incur the expense 

 of a bioassay (via Box 1.5), or by doing 

 a bioassay/bioaccumulation and 

 showing either significant mortality or 

 significant bioaccumulation (via Box 

 1.7). At this point, options for disposal 

 include either confined aquatic 

 disposal (i.e., capping) or upland 

 disposal if it is determined that the 

 material is unsuitable for marine 

 environment (i.e., that it will have "an 

 unacceptable adverse effect on the 

 marine ecosystem"). 



Box 1.9 "Unconfined Open-water 



Disposal " 



One arrives at this box via one of 3 

 possible pathways: 



a) Clean sand or coarser material is 

 being disposed which satisfies the 

 exclusion criteria (via Box 1.2); 



b) The material shows no elevated 

 levels of contaminants as a result of 

 the bulk chemical analyses (via Box 

 1.4); 



c) The material did show elevated 

 contaminant levels but no adverse 

 biological impacts as measured by 

 the bioassay/bioaccumulation tests 

 (via Box 1.7). 



A permit will be issued with a 

 specified period of validity for disposal 

 at one of the NED's nine disposal sites 

 (project-specific sites are also approved 

 in some cases). 



Box 1.10 



"Disposal Allowed? " 



At this point, the evaluator at NED 

 has material that is slightly or very 

 contaminated that shows evidence of 

 biological impacts. The regulations 

 specifically prohibit materials with 

 PCB's greater than 50 parts per 

 million, radioactive wastes, or inert 

 synthetic or natural materials which 

 may float. Also materials containing 

 any of the following in other than 

 trace contaminants shall not be 

 approved (ODA §22 7.3(c), 7/29/88:6A 

 revised draft): organohalogen 

 compounds, mercury and mercury 

 compounds, cadmium and cadmium 

 compounds; crude oil and its wastes, 



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



