ABSTRACT
Because effluent permitting based on concentrations of individual chemicals does not
accoun t for c ombined toxic effects, effluent toxic ity testing (Sect ion 24.4) was develop ed as
a means of monitoring the success of effluent permits. However, because effluent tests are
periodic, they are likely to miss episodes of high toxicity due to treatment failures, temporary
changes in a process, or other incidents. Continuous biological monitoring of treated effluents
has been proposed, but has not yet been adopted (Figure 39.1).
