documented association of 

 individual chemical concentrations 

 and subsequent biological effect. 



c) Even if any particular contaminant 

 levels are high, it has been 

 demonstrated in a number of 

 studies that sediment concentration 

 alone does not reflect 

 bioavailability (e.g., Carpenter and 

 Hugget, 1984). This is why bulk 

 chemistry results alone do not 

 disqualify material for open-water 

 disposal. 



The presence of so many uncertainties 

 is why this action box is used merely 

 as a screening level for 

 bioassay/bioaccumulation studies (Box 

 1.5). 



Box 1.5 



"Bioassay Needed for Further 

 Evaluation?" 



a) bulk contaminant levels are so high 

 that they exceed legally defined 

 hazardous levels (e.g., CERCLA or 

 Superfund) such that open-water 

 disposal is an unlikely option (Box 

 1.8); or, 



b) there is "reason to believe" or 

 questionable doubt that the 

 material may have an adverse 

 biological impact (again, an 

 undefined concept in the 

 regulations) that will be confirmed 

 by subjecting the material to a 

 bioassay and bioaccumulation 

 laboratory test (Box 1.6). The 

 "reason to believe" may be based on 

 past knowledge of sediment quality 

 in a harbor, the appearance (e.g., an 

 oily sheen) and smell of recovered 

 samples, or field evidence that few 

 (or no) organisms are recovered 

 with the sediment. 



If the levels from the bulk chemical 

 analyses are sufficiently high to cause 

 concern during the review at NED, 

 bioassay/bioaccumulation studies may 

 be needed to determine whether or 

 not capping shall be imposed as a 

 permit restriction, assuming efficient 

 capping is deemed feasible. At this 

 point, permittees can opt just to elect 

 capping (Box 1.8) as opposed to taking 

 the chance on paying for an expensive 

 testing procedure (Box 1.6; cost of 

 approximately $50,000 at the time of 

 this writing) and winding up having to 

 cap their project anyway. 



Sources of Uncertainty . There is no 

 null hypothesis being tested at this 

 point. It is really up to the reviewer to 

 decide if: 



A strong recommendation is to explore 

 the possibility of formally defining 

 criteria based on the historical data 

 available for determining when 

 biological testing is required to remove 

 some of the subjectivity from this 

 decision box. For example, some 

 objective criteria are available based 

 on the NERBC (1980) classification 

 scheme for sediment quality in New 

 England and the EPA/COE (1991) 

 Green Book guidance on the 

 Theoretical Bioaccumulation Potential 

 (TBP) for nonpolar organic 

 compounds. 



Box 1.6 



"Bioassay/Bioaccumulation " 



Requirements for biological testing 

 of the material are outlined in the 

 EPA/NED (1989) guidance document, 



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



