HA8 On-line Water Toxicity Monitoring
A105 & A106
8:00 AM - 12:00 PM, Thursday
() Development of a toxicity early warning system (TEW) for pulp and paper effluent.
Ingram, M.1, Lee, P.1, Momot, Walter1, Keeler, Warden1, 1 Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
ABSTRACT- A biomonitoring system is being developed for use in monitoring pulp mill effluent. The system, referred to as the Toxicity Early Warning system (TEW), utilizes rainbow trout (Oncorhynhchus mykiss) as an indicator species. It consists of several units of pairs of small tanks that function as flow through test chambers. One of the chambers contains a fish while the second (the reference) does not. The two chambers are connected to a Wheatstone bridge circuit. The current outputs of both tanks are then electronically compared, and the difference between the two are amplified and displayed as an AC current on a computer monitor. The reason for this design is that pulp and paper effluent is not homogenous, and the electrical signal from a fish could be masked by even small changes in the conductivity of the effluent. The Wheatstone bridge enables us to measure only the change in the signal from the fish and thereby correct for any effects from a non-homogeneous solution. Other advances to the design were the use of alternating current rather than direct current to prevent the build up of charge on the electrode surfaces and the confinement of the test fish in a mesh to prevent movement that also changes the electrical signal. The response of the trout to the effluent is used to develop toxicity profiles, that indicate what effluent components affect trout. Parameters used for this profile include the rate and amplitude of fish breathing, cough frequency, type of gill and fin movement, and whole body movement. Eventually, a complete trout response correlation will be developed and used to monitor the pulp mill effluent, thus preventing, and/or detecting future toxic spills.
Key words: Oncorhynhchus mykiss, Biomonitoring