and sulfates to prevent scale build-up. The low density of the water, 

 however, made the 5,000 gallon discharge float and it should not have 

 caused mortalities at the deeper stations. Table X, however, shows 

 mortalities in the deeper water were related to events surrounding 

 the shut-down periods, and that Stations 7A and 7B were also influenced. 

 The discharge from the boiler was probably too limited a volume to 

 influence Station 7. 



It was abundantly clear, however, that start-ups and shut-downs were 

 intimately associated with the mortalities at the biological stations 

 and that transient, high-level peaks of contaminants were more dele- 

 terious to the biota than steady-state operating conditions. The 

 sampling program focused on steady-state, long-term conditions and 

 was not designed to follow, and detect, sudden transients in levels 

 of contaminants. 



Although the plant operators were extremely cooperative during the 

 course of the study, the investigators were not frequently able to 

 obtain advance notice of when the plant would actually begin, or cease 

 operation so that they could be on site for complete following of 

 events. Most of the shut-downs were completely unpredictable, especially 

 when caused by unexpected blown boiler tubes or other emergencies. Sim- 

 ilarly, start-ups began as soon as repairs were completed and it was 

 often impossible to know in advance when a blown tube would be found 

 and repaired or when a pump would be made operational again. Conse- 

 sequently, only a few times during the study period could the research 

 team plan an adequate investigation of the transient peaks. 



In spite of this problem, plots of maximum effluent exposure against 

 mortalities did produce a reasonable pattern and the numerous deaths 

 shown in Figure 50 which appear unrelated to percentage of effluent 

 exposure are a reflection of unmeasured transient peaks of contaminants. 

 Since survival increased markedly when copper levels were reduced in 

 June, and since copper was the major contaminant during start-up periods, 

 it can be assumed the most deleterious constituent of the transient peaks 

 was copper. 



Figure 51 shows a plot of the average number of days of gorgonian 

 survival at Stations 2 through 7, compared with the average concentra- 

 tion of effluent at the "B" stations from August, 19 70 to March, 1971. 

 The solid line, representing days of survival at "B" stations, is clearly 

 inversely related to the amount of effluent present. As the effluent 

 concentration increased, survival decreased. Survival at the "A" series 

 stations is also plotted and shows a similar dependence on the effluent 

 concentration. Survival was greater at the "A" series stations since 

 the effluent concentration' was also less at these upper stations. 



124 



