ABSTRACT
Aquatic ecotoxicity tests measure the toxicity of chemical products on living organisms representing various trophic levels of the food chain in natural or man-modified ecosystems. The aim of ecotoxicity testing is to estimate the risk for the environment of the molecules with harmful effects on the flora and the fauna. About 20 tests or groups of tests on the bacterial ecotoxicity are available for assessing the toxic risks of pure chemical molecules or complex mixtures. Spirillum volutans is a rather large aquatic bacterium with flagella at each pole of the cell whose movement is not coordinated in the presence of a toxicant. Bacteria are living organisms whose different functions can be measured in order to assess the viability and/or the activity of the cells after being exposed to a toxic substance. The bacterial cells are limited by a cytoplasmic membrane and an extracellular structure: the cell wall, with at least two existing patterns called Gram-positive and Gram-negative.
