1.0 INTRODUCTION 



1.1 Disposal and Biological Monitoring History at MQR 



The Mill-Quinnipiac River Disposal Mound (MQR) is located in the southwest 

 quadrant of the Central Long Island Sound Disposal Site (CLIS), approximately 6 nautical 

 miles south of New Haven Harbor, CT (Figure 1-1). MQR is a capped mound formed by 

 the deposition of dredged material during the 1982-1983 disposal seasons. The mound has 

 been periodically monitored by the New England Division of the US Army Corps of 

 Engineers (NED) as part of the Disposal Area Monitoring System (DAMOS) Program since 

 the formation of the mound. 



The capped mound is actually a complex interlayered mound consisting of material 

 from the Mill River, the Quinnipiac River, Black Rock Harbor, and New Haven Harbor. 

 The disposal history of the MQR mound was compiled in recent DAMOS reports (SAIC 

 1994, Murray 1992). Although the mound has not received dredged material since 1983, 

 recent attention has been focused on MQR since routine monitoring data have indicated 

 anomalous recolonization relative to other CLIS disposal mounds formed at the same time. 



A history of habitat quality at several CLIS sites as documented by Remote Ecological 

 Monitoring of the Seafloor (REMOTS®) technology was compiled to chart the relative 

 progress of MQR. Three years after disposal, it was noted during the monitoring survey of 

 1986 that "MQR continues to have the slowest rate of benthic ecosystem recovery ..." 

 (SAIC 1990a). The following year, REMOTS® data indicated improving conditions, 

 although still below CLIS reference levels (SAIC 1990b). 



Monitoring activity has increased since June 1991 (Table 1-1) when the results of a 

 REMOTS® survey indicated an abrupt decline of habitat indicators (Wiley and Charles 1994). 

 One gallon of surface sediment also was collected from near the center of the MQR mound 

 for a 10-day amphipod bioassay in August 1991; percent survival rates for amphipods 

 exposed to MQR sediments ranged from 10 to 45%, as compared with control station 

 survival rates which ranged from 75 to 100%. Because of these results, a series of 

 investigations was initiated following the tiered monitoring protocols designed for the 

 DAMOS Program (Germano et al. 1994). The most recent REMOTS® survey was 

 conducted in August 1992 to assess the recolonization status one year after the June 1991 

 survey which triggered the investigations. 



1.2 REMOTS® Survey, Summer 1992 



Twenty-one stations were occupied during the 1992 survey at MQR. Triplicate 

 REMOTS® photographs were taken at each station. In addition to the REMOTS® survey, 

 sediment was collected for potential use in an amphipod bioassay. The sediment was 



Recolonization of the Mill-Quinnipiac River Disposal Mound (MQR): Results of a REMOTS® Survey, August 1992 



