Normally, copper concentrations at the "A" stations were similar 

 to control station concentrations. However, when the plant resumed 

 operations following maintenance, low salinities and high copper 

 levels were discharged and high levels of copper contaminated these 

 shallower stations. For example, at 1600 on January 17th, 1971 the 

 plant resumed operation after a one week shut-down. On the 18th, 

 at 0900, water samples were taken at the shallower stations in the 

 harbor which showed far more copper contamination than during normal 

 plant operation. 



The discharge, at 0900 on the 18th, had a copper concentration of 

 2,061 ppb. Normally, the "A" stations had close to zero percent 

 effluent reaching them, but following start-up, 3A had 2.3 percent 

 effluent calculated from the copper concentration. Station 6A had 

 2.3 percent and lA had 1.2 percent effluent. Stations 7A, 9A, and 

 SB remained close to their normal, low copper values until January 

 20th when all three stations showed abnormally high copper concen- 

 trations and effluent levels (3.3 percent at 7A, 2.0 percent at 9A, 

 and 1.6 percent at SB). 



Average monthly copper concentrations for combined Safe Harbor stations 

 are shown in Figure 19. Although copper concentration in the effluent 

 was high for October, 1970 (Fig. 10) the average copper levels in the 

 harbor were low. This was caused by two long shut-down periods (October 



4th to October 12th and October 25th to October 31st), and a single 

 start-up period. In December, when the plant shut down twice for 

 extended time periods (December 1st to December 9th and December 19th 

 to December 26th), there were two start-up periods and copper concen- 

 trations in Safe Harbor increased over the preceding month. Thus, 

 resumption of operation after maintenance not only brought about better 

 mixing of the effluent with the ambient water, but it significantly 

 increased copper levels in the harbor. 



64 



