Sediment toxicity assessment with Photobacterium phosphoreum:: A preliminary evaluation of natural matrix effect

In environmental toxicity testing, Microtox(R) Solid-Phase Test (SPT) is one of the most sensitive sediment bioassays; its real sensitivity and discriminatory power is however still unclear. SPT protocol is subject to several interferences related to the matrix variability that make it difficult to screen the genuine toxicity of solid-associated contaminants. In order to estimate natural matrix effect, correcting raw data from the main interference due to smaller particle size, it has been developed a preliminary relationship between the "natural" toxicity of 2 sets of clean reference samples of sediment (physically and chemically characterized) and grain-size particles. We also conducted some trial applications on harbour samples sediment, with the aim to purpose an example of harbor sediment toxicity classification.