control, Sylvan Slough, ALCOA, and Campbell's Slough solutions, respectively (Table 4). One- 

 way t-tests performed among respective porewater and storage control solutions, and the control 

 solution (USEPA 1989), determined that the ALCOA porewater solution significantly (p < 0.05) 

 reduced production of young by the C. dubia adults (Tables 4 and 5). 



Table 4. ANOVA table for Dunnett's Test of Significance for the reproduction data of the Survival/Reproduction C. 

 dubia test. A significant difference was detected between the production of young by organisms exposed to 

 replicate series of porewater solutions (p < 0.05). The mean square value for Between replicate series (373.43) was 

 larger than the mean square value for Within replicate series (14.64) indicating that most of the variance in the data 

 was found between the replicate series, or porewater solutions. This indicates that the significant effect detected 

 could be attributed to the effect of the porewaters on the organisms, and not on experimental error. 



Solution 



t-value 



Storage control 

 Sylvan Slough 

 ALCOA 

 Campbell's Slough 



-2.46 

 0.18 

 7.13* 



1.11 



Table 5. Calculated t-values for number of young produced in each porewater solution tested against the control 

 solution to determine significant effects of porewater on reproduction of C. dubia. 



♦Organisms exposed to ALCOA sediment porewaters produced significantly fewer young (45 df, p = 0.05. t-j = 

 2.225) compared to organisms exposed to the control solution and other porewaters 



3.2. Year 2 



3.2. 1 Ceriodaphnia dubia Survival / Reproduction Assay 



Only the porewater from Sylvan Slough sediments was available for the C. dubia survival / 



reproduction assay. Experimental error and poor health of the laboratory cultures prevented 



testing the remaining porewaters. The results from the C. dubia assays using Sylvan Slough 



20 



