Environmental samples, ecotoxicological classification

The general objective, principle, and scope of application of the pT-method are succinctly described in Section 1 and also reported elsewhere in this book (see Chapter 3 of this volume, Section 5.1), where readers will appreciate that this hazard assessment scheme is adaptable to both liquid and solid media. Briefly recalled here in the context of solid-media samples such as dredged material, the pT-value, which relates to a single bioassay, and the pT-index, derived from the most sensitive organism in a test battery, permit a numerical classification of environmental samples on the basis of ecotoxicological principles. Sediment from any aquatic ecosystem (freshwater, brackish, marine) and from any of its phases (whole sediment, porewaters, elutriates or organic extracts) can be appraised provided that the proper standardized toxicity tests are available. There are whole-sediment test protocols standardized for many agencies (e.g., Environment Canada, ASTM). 

Numerical ecotoxicological classification of environmental samples attained with a test battery. The pT-value of the most sensitive organism within a test battery, the pTmax-value, determines the toxicity class of an investigated sample. Roman numerals are assigned to each toxicity class which corresponds to a pT-index. Volume 2(3). 

The possibility of including ecotoxicological studies in the monitoring of environmental pollution should therefore be considered. Beforehand, however, an appropriate classification of environmental samples will need to be prepared, a suitable ecotest chosen, and implementation tests conducted. 

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