124 



BIOLOGICAL REPORT 31 



sediments. Compounds may, however, reenter the 

 system directly by resuspension or indirectly by in- 

 gestion by benthic communities with possible transfer 

 up the food chain. Because PCB's have been found 

 in birds like the ring-billed gull and in white-footed 

 mice (Peromyscus sp.), it is clear that food chain 

 transfer of this contaminant is occurring, possibly 

 resulting in biomagnification of the toxin with in- 

 creased predator size. Of additional concern are 

 potential alterations to the benthic communities with 

 shifts to more pollution-tolerant species, which may 

 in turn modify the prey resource for other species, 

 especially bottom-feeding fish. Unfortunately, the 

 cooccurrence of many pollutants within the con- 

 taminated areas makes it impossible to accurately 

 identify this effect. The good news is that PCB, or- 

 ganic toxin, and heavy metal inputs to the bay 

 through water flows can be controlled by environ- 

 mental management practices because they tend to 

 be point sources and can be adjusted before dis- 

 charge. The major problem in this area, at present, 

 is the remediation of previously discharged com- 

 pounds. 



The New Bedford/Fairhaven area discharges 

 almost all of the toxic pollutants and heavy metals 

 and more than half of the sewage inputs to the bay 

 (cf. Chapter 6). This historic "concentration of im- 

 pacts" has led to an isolation of ecological degra- 

 dation in the nearshore zone (Howes and Taylor 

 1990; Costa et al. 1992) of one of the bay's 27 

 embayments. 



Other sources of toxic pollutants to Buzzards 

 Bay tend to have more widespread inputs and are 

 therefore more difficult to manage; however, most 

 of these inputs are small, such as road runoff or the 

 leakage of nonvolatile and volatile compounds from 

 recreational outboard motors (the notable excep- 

 tion is infrequent but dramatic oil spills). Increased 

 effectiveness of quick response to large and small 

 oil spills and improved cleanup techniques designed 

 to minimize impacts are now being supported by 

 spill prevention methodologies within the bay's har- 

 bors. As with all human introduced compounds, the 

 focus of management on prevention of discharge 

 rather than remediation is becoming the standard. 

 The impacts of recent Buzzards Bay spills remain 



fresh in the memory of many and provide a base for 

 management. At present, however, the inputs of 

 hydrocarbons in sewage effluent, industrial dis- 

 charges, and stonnwater runoff may actually equal 

 the inputs from accidental spills (Farrington and 

 Capuzzo 1 990). Efforts to increase awareness of 

 citizens of their role in oil inputs and to develop regu- 

 lations aimed at minimizing inputs from these sources 

 are underway for Buzzards Bay by local communi- 

 ties as well as regionally through the bay-wide Buz- 

 zards Bay Project and Coalition for Buzzards Bay. 



7.2. Coliform 

 Contamination and 

 Shellfish Closures 



One of the primary consequences of increased 

 pollution in Buzzards Bay is reflected by the signifi- 

 cant increases in shellfish bed closures in recent 

 years (Fig. 6. 1 ). The parallel between the increase 

 in these closures and increasing development in the 

 bay watershed has led many to conclude that faulty 

 septic systems are the primary culprit. Evidence is 

 increasing, however, that although septic systems 

 are a potential cause, other sources may be more 

 important (Heufelder 1 988; P. Weiskel, U.S. Geo- 

 logical Survey, Marlborough. Massachusetts, per- 

 sonal communication). Although measurements of 

 fecal coliform bacteria are not accurate indicators 

 of sewage contamination (or for that matter nutrient 

 pollution) because of the various sources of bacte- 

 ria, the trend in shellfish closures due to coliform 

 contamination does reflect the increased popula- 

 tion growth along the bay. In 1 970, an average of 

 1 ,78 1 ha of shellfish beds were closed due to the 

 presence of this enteric bacteria. In 1988, how- 

 ever, more than 4.452 ha were closed, about 

 10% of the total hectarage of open shellfish beds 

 in Buzzards Bay (this figure temporarily surged to 

 7,689 ha after the New Bedford sewage treatment 

 plant released 378,500 L of sewage into the bay). 

 In 1 989, roughly 5,059 ha were closed; in 1 990 

 this number grew to nearly 5,666 ha. indicating a 

 continual and steady increase in shellfish bed clo- 

 sures for Buzzards Bay waters. These closures are 



