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attained by July 1991 for North River and August 1989 for Red Hook. If 

 disposed at the 12-Mile Site, advanced preliminary treatment will result 

 in a 3.4 percent increase in digested sewage sludge solids ocean dumped 

 in 1981 (Chapter 5). Furthermore, if the observed decreases in con- 

 taminant concentrations in sewage sludge continue (Section 6.7), the 

 quantities of major contaminants dumped via sewage sludge will decline. 



2.11 OTHER ENVIRONMENTAL FACTORS 



Fish populations of the New York Bight are dominated by migratory coastal 

 species which have high reproductive capacities and support large com- 

 mercial and recreational fisheries (Section 12.4), Annual fluctuations 

 in year class abundance typically result from climatic variability and 

 are affected by over-exploitation by the sport and commercial fisheries 

 (Section 12.5). The dumping of sewage sludge at the 12-Mile Site is not 

 believed to have adversely affected the finfish resources of the New York 

 Bight and, no critical life stages of important species are unique to the 

 vicinity of the dumpsite (Section 12.5). 



Oceanic diffusion studies indicate that at the end of the four hour 

 "initial mixing" period following discharge at the site, the sewage 

 sludge is diluted one part sewage sludge to about 30,000 parts of sea- 

 water (Section 18.2). This is a result of a two phase process: a very 

 rapid initial wake dispersion, followed by slower oceanic diffusion 

 processes. The EPA/Corps of Engineers "release zone method" of esti- 

 mating initial mixing has been shown to be conservative when compared 

 to results of field studies conducted to evaluate the behavior of ocean 

 dumped sewage sludge (Section 18.2 and 13.3). 



Concentrations of dissolved metals and particulate organic materials in 

 the water column of the New York Bight vary naturally both seasonally and 

 spatially, with background concentrations for some constituents generally 

 higher than those reported for the open ocean, but within ranges found in 

 other coastal waters (Sections 7.1 and 7.2). There are numerous sources 

 of these nutrient, metal, organic, and suspended material constituents to 

 the Bight, with sewage sludge dumping being only a minor source (Section 

 6.5). Water quality effects following dumping are temporary, and concen- 

 trations generally return to background levels within several hours. 



2.12 SURVEILLANCE AND MONITORING 



Surveillance and monitoring programs are well established for dumping 

 activities within the New York Bight apex. Conducted by EPA, NOAA, U.S. 

 Coast Guard, and state agencies, as well as through a cooperative effort 

 of regional sewage sludge permittees, these efforts have resulted in an 

 extensive environmental baseline database against which environmental 

 changes can be compared (Section 19.2). Similar surveillance and moni- 

 toring activities at the 60- or 106-Mile Sites would be far more costly 

 and difficult to conduct, and the information obtained would be more 

 difficult to interpret because such extensive databases are not available 

 for these sites. 



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