220 



1 THOMAS SAUNDERS ENGLISH 



2 threshold exists somewhere around 10 ppm SWL." The report 



3 notes that "damage induced at 10 ppm is not significantly 



4 increased by augmented concentrations of SWL until approxi- 



5 mately 180 ppm SWL. Above this concentration, survival of 



6 exposed eggs is hopeless." The suggestion of a critical 



7 threshold at 10 ppm SWL is based on statistical treatment 

 g of the data. However, the figure which relates the per- 



9 centage of eggs inhibited to concentrations of PBI reveals 



10 that "significant retardation does not occur until SWL 



11 concentrations exceed 180 ppm." The Federal report then 



12 recommends that the Everett mills "put into operation appro- 



13 priate abatement measures to reduce SWL concentrations 



14 in the surface waters to less than lA ppm. Therefore, 



15 the allowable level of SWL in Port Gardner is apparently 

 Ig related to the results of bioassay studies of the English 



17 sole egg. 



18 Since the English sole population in Port 



19 Gardner seems to be in very good condition, I have had to 



20 wonder how the recommendation in the Federal Report came 



21 to differ so widely from my understanding of the situation. 



22 Several possibilities can be suggested. 



23 1. The English sole eggs used in the bio- 



24 assay were of poor quality or were subjected to undue stress. 



25 2. The results of the bioassay were somehow 



