1.0 INTRODUCTION 



The Massachusetts Bay Disposal Site (MBDS) is located in the northeast portion of 

 Massachusetts Bay, approximately 18 nmi east-northeast of the entrance to Boston Harbor 

 and 10 nmi south-southeast of Gloucester, Massachusetts. The site described in this report 

 refers to an interim location prior to final designation in 1993. This interim disposal site 

 consisted of a 2 nmi diameter circle centered at 42° 25.700' N and 70° 34.000' W. The 

 MBDS boundary overlaps a portion of the old Industrial Waste Site which had been in use 

 since the 1940s for the disposal of dredged material as well as other waste. The Industrial 

 Waste Site, a 2 nmi diameter circle centered approximately 1 nmi west of the present site, 

 was the recipient of many types of matter not limited to dredged material, including building 

 debris, canisters of industrial waste, and encapsulated low-level nuclear waste. 

 Environmental Protection Agency (EPA) records show no permitted use of the industrial 

 waste site after 1976, and it was formally dedesignated on February 2, 1990 (Wiley 1991). 

 The MBDS has been used for the disposal of dredged material since 1977. 



SAIC has conducted five monitoring surveys at MBDS from 1985 to 1990. An 

 extensive survey was conducted in 1985 to determine if the existing site should receive final 

 designation while more recent studies were designed to monitor the site (SAIC 1987a, 

 1989b). These studies determined the extent of dredged materials, monitored the formation 

 of the disposal mound, evaluated the benthic environment, provided information on the 

 physical parameters of the site, and determined the extent of chemical contamination. 

 Assessment techniques for the surveys have utilized precision bathymetry, side-scan sonar, 

 REMOTS® sediment-profile photography, current meter and transmissometer deployments, 

 CTD/DO monitoring, and sediment and benthic faunal sampling for physical and chemical 

 analysis. The 1985 survey also included observational cruises utilizing manned submersibles, 

 fish collections, and the implementation of the Benthic Resources Assessment Technique 

 (BRAT). 



Major construction projects underway in the Boston area (the Central Artery/Third 

 Harbor Tunnel project and the relocation of the Deer Island outfall) will likely create a 

 substantial increase in disposal activity at MBDS over the next several years. MBDS 

 received an estimated 260,300 m 3 of dredged sediments since the last bathymetric survey in 

 November 1988. The sediments deposited at MBDS have been a mix of sands, silts, and 

 clays which have met regulatory requirements for open water dredged material disposal 

 (Table 1-1). Barge logs indicated that most of this material was deposited within 400 m of 

 the "MDA" (formerly the "FDA") buoy, centered at 42° 25.086' N and 70° 34.457' W. 



The oceanography of MBDS is influenced, in part, by the circulation of the Gulf of 

 Maine. The Gulf of Maine circulation patterns in the vicinity of MBDS are modified to a 

 large extent by the presence of Stellwagen Bank on the eastern margin of Massachusetts Bay 



Monitoring Cruise at the Massachusetts Bay Disposal Site, August 1990 



