navigation channel, downstream from Stockton. 



The USGS study is a survey of freshwater aquifers from Carquinez 

 Strait, through Suisun Bay to the confluence of the Sacramento and San 

 Joaquin River, at Sherman Island. The results of these two studies are 

 pending. 



A similar survey of San Francisco and San Pablo Bays is being con- 

 ducted jointly by the USGS and the Department of Housing and Urban 

 Development. In addition, the San Francisco District of the Corps of 

 Engineers plans to monitor freshwater aquifers in the area for potential 

 salinity intrusion during and after dredging operations. 



7. Puget Sound 



Studies of the effects and fates of digested sludge disposed through 

 outfalls in the Puget Sound area, have been performed by a number of 

 investigators. Brooks, et al (1965) studied outfall designs and gave 

 predictions for sludge accumulation. An earlier study by Sylvester (1962) 

 pointed out potential problems arising from the increase in the nutrient 

 content of the water, the sludge accumulation, the floatable materials, 

 and the effects of such factors on the marine ecology. Servizi, et al 

 (1969) studied the effects on sockeye and pink salmon of dredging and dis- 

 posal of sediments from Bellingham Harbor, known to contain paper mill 

 pulp fibers and hydrogen sulfide. They recommended that before dumping 

 such sediments in open waters, four factors shpuld be considered: (a) 

 turbidity created during disposal; (b) the biochemical oxygen demand of 

 the sediment; (c) the release of toxic hydrogen sulfide during disposal; 

 and (d) generation of hydrogen sulfide by the sediments after they set- 

 tled. 



Consideration of possible dredge spoils disposal sites in Puget Sound 

 resulted in a study by the Department of Fisheries, State of Washington 

 of the bottom sediments of Olympia Harbor (Westley, et al, 1972). The 

 sediments of Olympia Harbor have a volatile solids content that exceeds 

 the 6 percent standard recently set by the Environmental Protection Agency 

 as the limit for marine disposal (EPA, 1972). The study evaluated the 

 status of the sediments and their possible toxic effects. 



Chemical analyses of the bottom sediments of Olympia Harbor indicated 

 considerable variation between stations in this harbor and the unpolluted 

 control station on Oro Bay. The volatile solids, biological oxygen demand, 

 (BOD), and sulfides of Olympia Harbor appeared to be in concentrations 

 about 1/3 of the way between presumably unpolluted areas and those of 

 areas considered to be highly noxious. 



Bio-assays conducted to detect possible direct toxicity to phyto- 

 plankton, showed no such effect, although settling of silt was observed to 

 entrap phytoplankton organisms. A major stimulating effect on the 

 photosynthetic rate of phytoplankton was observed with increased nutrient 

 concentrations in the bottom sediments. During the course of the 



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