56 



species) collected at capped mounds (Table 

 3-1). At MQR and FVP, Cr and Cu levels 

 were elevated above reference values both 

 in surface sediments and in the tissue of 

 the polychaetes. These results suggested 

 some correlation between sediment 

 contaminant levels and bioaccumulation. 

 The similarity between sediment and body 

 burden values for MQR and FVP also 

 suggested that inorganic contaminants were 

 not responsible for the observed slow 

 recolonization rates at MQR (SAIC 

 1990a). These values are comparable to 

 results from other body burden analyses 

 from the former CLIS reference station 

 and FVP (Munns et al. 1989). 



In contrast, elevated concentrations of 

 Cr, Cu, and Zn in Nephtys at STNH-N did 

 not correspond with elevated sediment 

 levels of these three metals. All other 

 evidence has suggested that the sand cap at 

 STNH-N has been effective in physically 

 isolating or diluting the metal 

 concentrations in the surface sediments 

 (Fredette et al. 1992). It is important to 

 note that the metal levels measured in 

 these worms are still low relative to results 

 from urban estuaries in the United States 

 and Europe (Reish et al. 1981, Long and 

 Morgan 1990). The data are clearly not 

 adequate to make conclusive statements 

 regarding the sources of contaminants 

 measured in biological communities 

 collected from capped dredged material 

 mounds. 



recolonization responses. If a capped 

 mound is apparently unhealthy, it may be 

 very difficult to collect sufficient quantities 

 of Stage III species to conduct the 

 analyses. Successful measurement of 

 contaminant body burdens in Stage I 

 species would help determine whether or 

 not an apparently normal recolonization 

 rate and a dense Stage I community are 

 synonymous with acceptable environmental 

 quality. Techniques are in development 

 for improving efficiency of collection of 

 Stage I organisms for conducting such 

 experiments (Rhoads et al. 1994). 



3.2.5 Biological Monitoring: 

 Conclusions 



The methods of biological monitoring 

 have varied since the conception of 

 DAMOS. Since 1982, biological 

 monitoring has emphasized REMOTS® 

 technology. All methods have confirmed 

 and expanded on many of the physical 

 monitoring results: 



• No data from the early biological 

 monitoring approaches (caged 

 mussels, body burden analyses) 

 suggested that contaminant signals 

 were related to the capped mounds. 



• REMOTS® data have allowed the 

 quantification of recolonization 

 rates and the overall biotic health of 

 a capped mound. 



Experiments on bioaccumulation of 

 contaminants in Stage I organisms (very 

 small polychaetes and amphipods) would 

 facilitate interpretation of anomalous 



Monitoring at MQR included initial 

 REMOTS® studies followed by 

 bioassay analyses, and this 

 "response" monitoring was 



Sediment Capping of Subaqueous Dredged Material Disposal Mounds 



