• measure near-bottom and surface DO concentrations at the active disposal site 

 and reference areas. These data were used to assess the potential role of DO 

 as a biologically important variable for benthic recolonization. 



• collect sediment samples at the three reference areas to provide information on 

 percent total organic carbon (TOC), grain size, and potential effects of the 

 following contaminants: poly nuclear aromatic hydrocarbons (PAHs), cadmium 

 (Cd), lead (Pb), and zinc (Zn). 



The 1991 monitoring plan was designed to test the following predictions that are part 

 of the DAMOS tiered monitoring protocol: 



• Based on a disposal simulation model, the volume of sediments disposed near 

 the NL-TR mound from September 1990 to May 1991 should result in 

 formation of a mound with a radius of approximately 150 m and height of 



2 m. Further disposal is expected to contribute additional material to the cap 

 at this location. 



• On the active area of the disposal site, recolonization will be dominantly Stage 

 I, while recolonization on the flanks of the mound will be primarily in Stage II 

 and/or Stage III. Stage I consists of small pioneering polychaetes, whereas 

 Stage II is characterized by tubicolous amphipods, and Stage III by larger 

 burrowing (head-down) deposit feeders. Stage III taxa represent high-order 

 successional stages typically found in low disturbance habitats. 



• Near-bottom DO concentrations should be similar at stations within the 

 disposal site compared to reference areas. 



Monitoring Cruise at the New London Disposal Site, June 1991 



