10-40 



ANALYSIS OF IMPACTS 



The supply of trace metals from domestic and industrial sewage 

 is imprinted on the sediments adjacent to the source of impact as we 

 have seen in the first section. The organisms feeding on suspended 

 organic material respond in their trace-metal concentration to this 

 input. New Haven Harbor is one such impacted area but does not influ- 

 ence the biota as strongly as the Housatonic River or Throgs Neck (East 

 River) systems. Changes in trace-metal supply with time exist in some 

 locations around the Sound, but they are not marked in New Haven Harbor 

 as reflected in the long time-scale study of Mercenaria mercenaria at 

 two sites in the harbor. 



The role of New Haven Harbor Station as a potential source of 

 trace-metal input in New Haven Harbor is limited. Surface runoff from 

 the plant site and leachate from the percolation lagoon that receives 

 treated plant wastes are the most probable sources. The addition of 

 trace metals to the condenser cooling water during plant passage is 

 effectively eliminated since the condenser tiibes are titanium, a metal 

 extremely resistant to corrosion and erosion and the txibesheets are 

 alximinum with bronze epoxy- coating. Contributions from plant-site 

 runoff, consisting primarily of dust particles and other material from 

 atmospheric sources, is not expected to be different from other similar- 

 sized land areas around the harbor. The percolation lagoon receives 

 treated effluents from such in-plant sources as floor drains and demin- 

 eralizer regeneration wastes. The leaching of trace metals from the 

 percolation lagoon into the harbor is dependent upon the composition 

 (permeability and sediment type) of soils underlying the lagoon. Any 

 contribution from this source would enter the harbor via the ground- 

 water, most probably in the vicinity of the plant waterfront and the 

 drainage ditch located to the south of the plant property line. This 

 contribution would be insignificant compared to metals entering the 

 harbor from the adjacent sewer outfall. 



