Canadian application of microbiotests to assess the toxic potential of complex liquid and solid media

Abstract

Microbiotesting activities comprise one important approach to address the issue of chemical contamination and its potential impacts on water quality and biota of receiving aquatic ecosystems. Under the second Saint-Lawrence River Action Plan (1993-1998), the Centre Saint-Laurent (Environment Canada, Québec Region, Montréal) continued its development and application of microbioanalytical tools and techniques to assess, control and prevent point source pollution of industrial origin to the freshwater portion of the Saint-Lawrence River ecosystem. In this review, some of the major studies conducted in the area of microbiotesting are highlighted These include 1) adapting the Microtox® acute toxicity assay in a 96-well microplate format to markedly increase its sample throughput capabilities, 2) employing the SOS Chromotest™ to determine the genotoxic status of major industrial effluents discharging to the Saint-Lawrence River and their potential impact on downstream biota, 3) developing an alternative to whole fish acute (sub)lethal toxicity testing with the help of rainbow trout primary hepatocytes, 4) developing a simple microplate-based Hydra toxicity assay as an effective screen for chemicals and various environmental media, 5) developing a novel algal solid phase assay to predict the toxic potential of freshwater sediments, and 6) conducting a major investigation to develop a cost-effective multitrophic bioanalytical battery to assess the (geno)toxicity of freshwater sediments. The aforementioned studies are but a few examples of the diverse and bustling research endeavours presently ongoing internationally in microbiotesting and many important challenges still lie ahead for this field well into the third millennium.