The similarity of the stations in terms of their benthic 

 infauna can be estimated roughly by assessing the number of 

 dominant species shared between each possible couplet of stations. 

 Out of the 10 top dominants, about 7 taxa (6-9) were shared between 

 all disposal mound couplets, whereas only 2 to 5 species were 

 shared between reference station couplets. Comparison between the 

 mound and reference stations shows that 7 to 8 species were shared 

 between stations Rl and each mound station (except station 22 with 

 only 4 species shared) ; 6 species were shared between stations R2 

 and each mound station, but only 4 species were shared between 

 stations R3 and each mound station (except for station 22 with 6 

 species shared) . 



The total number of taxa and individuals per benthic 

 sampling station at BBDS is provided in Appendix A, and a 

 comprehensive list of macrobenthic invertebrates collected from 

 BBDS is provided in Appendix B. Two species are suggested for 

 future body burden analysis, Ninoe nigripes and Nephtys incisa. 

 Both of these species are sufficient in number and size to allow 

 for collection, concentration, and subsequent clean preservation 

 (freezing) . Mediomastus ambiseta and the remaining species in the 

 dominance lists are small and do not lend themselves readily to 

 collection procedures. 



3.4 Sediment Analysis 



3.4.1 Grain Size Analysis 



Physical and chemical parameters were developed in 1980 

 by the New England River Basin Commission (NERBC) to assist in 

 interpreting the nature of dredged material. NERBC classifications 

 were used for interpretation of percent fines (percent silt and 

 clay) and in the following section on sediment chemistry for 

 interpretation of metals, pesticides, and PCB results. 



The distribution of sediment grain size (Table 3-2 and 

 Figure 3-18) corresponds with that mapped from REMOTS® photos (see 

 Figure 3-2) . Major modal grain size over the surveyed area ranged 

 from medium sand (2-1 phi) to silt-clay (>4 phi) . The percent silt 

 and clay for the disposal site stations and reference areas 1 and 

 2 fell into the NERBC Class 1 (< 60%) category. Reference area 3 

 contained a Class II (60-90%) level of silt and clay. 



Fine sands (4-2 phi) dominated over medium sands (2-1 

 phi) for all stations tested, except at the center of reference 

 area 1, where the percent of fine and medium sands was equal at 

 44%. Results for reference station 1-200W and reference station 3- 

 200W also demonstrated a fairly even distribution between medium 

 and fine sands. Percentages of medium sands were, however, much 

 lower for reference area 3. Station 1 center and station 20 

 contained the highest percentages of sands, 94% and 97%, 

 respectively . 



8 



