This message was bounced by the listserve so I am forwarding my
colleague's response.  F. McCormick

>>
Hi

My office mate and colleage Frank McCormick forwarded your message
to me. Our opinion is that your problem is not a pathogen because the
response is to quick. My thoughts are as follows:

Things that fatheads are more sensitive to than Ceriodaphnia are:

a) H2S - your TIE should have elliminated it if you used the aeration step

b) Nitrogen gas posioning - your TIE should have elliminated this with the
aeration step as well.

c) Diazon - your C18 step should have indicated whether this was a
problem.

d) polymers - certain polymers may effect fish and not Ceriodaphs and
would be filtered out by the 0.45 micron filter.

e) the mode of toxic response seems to indicate a narcotic effect.

Hope this helps.

jim