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REMOTS® postdisposal surveys indicated that recolonization was occurring at all of 

 these mounds, including FVP, and that MQR was the slowest to recover. Hurricane Gloria 

 had a substantial impact on the benthos at most of the CLIS mounds in 1985, especially the 

 FVP mound (Figure 4-2). Following the Hurricane Gloria survey, two REMOTS® surveys 

 in 1986 and 1987 documented the cycle of recovery following the storm and again indicated 

 that MQR did not recover quite as quickly as the other mounds. 



The 1986 survey at CLIS concluded that the lowest mean OSIs occurred at STNH-S, 

 NH-83, and MQR, which are all located along the southern border of CLIS (Figure 1-1). 

 One suggestion to explain this phenomenon was hypoxic bottom water conditions, 

 concentrated at the southern rim of CLIS, which would prevent or inhibit colonization of 

 these mounds (SAIC 1990a). 



The 1986 report also noted that MQR "continues to have the slowest rate of benthic 

 ecosystem recovery, possibly the result of chemical contamination combined with hypoxic 

 effects." RPD values were significantly shallower than at the reference area. The low OSI 

 values were a function of the thin RPDs, dominance of Stage I, and presence of methane. 

 Surface sediment chemistry results from MQR indicated that the mound had statistically 

 higher concentrations of metals and oil/grease relative to reference area values. Conversely, 

 the FVP mound showed that trends towards shallower RPDs which had been documented in 

 March and October of 1985 had been reversed and that the percent of stations showing Stage 

 III had increased (SAIC 1990a). 



In the following year, MQR had RPDs which were consistently deeper than the 

 previous survey (SAIC 1990b). The presence of dredged material and pockets of methane 

 were similar to the previous survey. Methane was noted as being unusually high and 

 persistent in this sediment. The presence of Stage III organisms increased from 31% of 

 replicate images in 1986 to 46% in the 1987 survey. 



The OSI is sensitive to conditions which cause stress to the benthic environment. A 

 clear example is the passage of Hurricane Gloria; surveys were conducted immediately 

 following the storm, and the resulting change in OSIs demonstrates the substantial effects on 

 the benthos (especially at the mound apices), most clearly displayed at the FVP mound 

 (Figure 4-1, Figure 4-2). 



Comparing MQR and FVP is appropriate since (1) they were created at the same time 

 and (2) FVP remained uncapped and MQR capping material apparently contains some 

 elevated levels of contaminants (Murray 1992). Figure 4-2 shows the average OSI from all 

 stations within 100 meters of the center station for both MQR and FVP through time. 



Postdisposal surveys at both MQR and FVP indicated that benthic communities of 

 both were detrimentally affected by disposal of dredged material. Although FVP was 



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



