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Sediment Quality Assessment and Management: Insight and Progress Edited by M. Munawar© 2003 Ecovision World Monograph Series Aquatic Ecosystem Health & Management Society Canadian application of bioassays for environmental management: a review C. Blaise Centre Saint-Laurent, Environment Canada, 105 McGill Street, Montreal, QUE, H2Y 2E7 Canada. Keywords: regulations, contaminants, effluents, sediments Introduction Ecotoxicological approaches for managing aquatic environments can call for use of bioassays, biomarkers or in situ indicators, depending on the issues at stake and on the questions being asked (Fig. 1). In all cases, chemical analysis becomes an essential component of ecotoxicological investigations in an attempt to relate observed effects to putative causes of contamination. In situ approaches essentially strive to determine the health status of particular aquatic ecosystems by measuring structural or functional indices at the level of biotic populations. Such investigations are useful, for example, in evaluating a previously unstudied milieu or one in which (non) point sources of pollution have recently been dealt with so as to see how applied corrective measures have ameliorated a once-deteriorated receiving environment. Whether conducted through laboratory or field experimentation, biomarker measurements of exposure and effects are indeed useful to detect subtle sublethal effects, which can affect specific populations of biota at biochemical, physiological and/or behavioural levels. These so-called hidden effects, which biomarkers can bring to light at the molecular scale, can often be the forerunners of irreversible effects, which may have long term consequences for faunic species. Biomarkers are therefore essential tools to appraise the ways in which particular contaminants may aggress specific biota, as they generate information on targeted organs and cellular sites, as well as on toxic mechanisms of action. At the forefront of dedicated efforts to cope with ecotoxicity are multitrophic bioassays, undertaken at various levels of biological organization with (sub) cellular systems, bacteria, 40 Fig. 1. Ecotoxicological tools and approaches for managing aquatic environments (from Blaise, 2000). 41 algae, protozoans, micro-invertebrates, amphibians and fish (Wells et al., 1998). Because bioassay organisms integrate all possible interactions, which can occur when they are exposed to the singular or combined influence of bioavailable toxicants, they are now recognized as essential means of measuring the potential adverse effects of chemicals and complex (liquid and solid) media. In Canada, environmental protection strives to follow cognitive, curative and preventive pathways to achieve optimal results. In an ecotoxicological context, it is clear that curing environmental problems and preventing them from reoccurring must be preceded by knowledge (cognition) of ecotoxic effects which can only come from bioassay-derived data followed by cause identification (chemical analysis). In the ensuing sections, the major elements comprising Canada’s national environmental management program are described (Fig. 2) as they apply to insure the safety of aquatic ecosystems from toxic insults. Environment Canada’s toxicology test method development program To guarantee that reliable procedures would consistently be employed to generate toxicity data in Canada, it was deemed essential that a National Toxicology Test Method Development Program (NTTMDP) be first implemented for this purpose. This program resulted in part from a 1988 Environment Canada Workshop held to discuss “the role of biology in the new regulatory framework for aquatic protection” in which opinions from government, industry, consultants and university sectors were voiced (Environment Canada, 1988). This workshop served to address deficiencies in the current state of toxicity test usage in Canada and identified the roles of various stakeholders to correct this situation. Shortly thereafter, the NTTMDP program was implemented by Environment Canada which clearly outlined a test method standardization approach calling for 1) the preparation of a formal draft test method document for each bioassay intended for standardization, 2) a critical review by an expert subcommittee, 3) the preparation of a final draft test method, 4) an international peer review of each test method, 5) the finalization of each test method and 6) the formal publication of an Environment Canada toxicity test method document. Through this process, the first three of Environment Canada’s biological test methods were released as early as 1990 (Environment Canada, 1990a, 1990b, 1990c). Developing standardized toxicological methods in this fashion would first and foremost contribute to incorporating a reliable biological component in ecotoxicological hazard assessment schemes. It would also ensure the proper use of test methods in legislative requirements, national consistency in testing, as well as quality assurance for clients. As useful adjuncts to standardized test methods, several complementary supporting guidance documents were prepared to further ensure quality of bioassay Table 1. Update of Environment...


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