Ecotoxicological evaluation of sediments by battery bioassays: application and comparison of two integrated classification systems

There is a recognised need to integrate multiple toxicity data deriving from battery bioassays into an easily understandable and single value, which may facilitate the decision-making process related to the management of contaminated sediments. In this study, two integration results systems were applied and compared: toxicity classification system (TCS) and Toxicity Test Battery integrated Index (TBI). The quality of sediments of the Taranto seas (Mar Grande and Mar Piccolo) was assessed by a battery of five test species representing different trophic levels (Dunaliella tertiolecta, Tigriopus fulvus, Corophium insidiosum, Mytilus galloprovincialis, and Anphibalanus amphitrite) and performed on three exposure phases (elutriate, porewater, and whole sediment). The integration of biological tests results with TBI showed that stations located in Mar Grande and one station in Mar Piccolo were in the high ecotoxicological risk level, according to the results obtained with TCS. The comparison of results deriving from two evaluation systems showed similarity in the ecotoxicological risk level. Only in one case there was a lack of concordance between two indices giving opposite judgments. The present study demonstrates that the use of one of the two indices can be useful to estimate and to rank hazard level for sediments.