Sed-tox index

THE SED-TOX INDEX FOR TOXICITY ASSESSMENT OF CONTAMINATED SOLID MATRICES... 

The purpose of this paper is to describe the SED-TOX index for the toxicity assessment of contaminated solid matrices, particularly sediments, demonstrate its discriminative potential, and show its correlation with chemical analyses derived data and indices of benthic community structure. 

In the first publication (Bombardier and Bermingham, 1999), the SED-TOX index was applied to toxicity data obtained from marine sediments collected at two sites in the Gulf of St. Lawrence Anse-a-Beaufils (Gaspe, Quebec, Canada) and Cap-aux-Meules (Magdalen Islands, Quebec, Canada). Three areas (harbour, disposal, and reference) were evaluated for each site. The following questions were addressed in this particular study ... 

In the second publication (Bombardier and Blaise, 2000), laboratory toxicity data derived from two larger projects conducted on freshwater sediments were integrated in the SED-TOX index and it was field validated using four benthic community metrics (species richness, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, the Shannon-Wiener diversity index, and the ICI-SL which is a version of the Invertebrate Community Index modified for the St. Lawrence River). 

As demonstrated previously (Bombardier and Bermingham, 1999 Bombardier and Blaise, 2000), the SED-TOX index has a good discriminatory potential. 

Another noteworthy limitation of the SED-TOX index, which is actually a limitation of toxicity bioassays, relates to the fact that results measured in toxicity tests only provide a measure of what is occurring under very specific laboratory test conditions, and an indication of what is or could occur in the field. To maximize the ecological relevance of the laboratory toxicity tests, there is a need to relate the SED-TOX scores with a series of benthic community matrices. 

Toxicity tests, which are used to generate the SED-TOX index, cannot substitute for chemical measurements or for surveys of benthic communities. On the contrary, the strength of toxicity tests, and hence the SED-TOX index, are best realized in conjunction with chemical and biological field measurements. These three approaches form a natural triad in which each component enhances the power of the others (Sergy, 1987). 

This section illustrates how the SED-TOX index has been effective in assessing the relative toxic potential of freshwater sediments to aquatic organisms. The index was... 

Bombardier, M. and Bermingham, N. (1999) The SED-TOX index Toxicity-directed management tool to assess and rank sediments based on their hazard - Concept and application, Environmental Toxicology and Chemistry 18, 685-698. 

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