De la régénération céphalique de l'Oligochète Lumbriculus variegatus Müller à l'étude de la toxicité des métaux lourds

Abstract

This paper studies the subacute toxicity of various metallic contaminants (copper, lead and platinum) already or potentially present in the environment. We used as a test organism a freshwater invertebrate, Lumbriculus variegatus (Annelid, Oligochaeta), widespread in this area. This worm reproduces only asexually (architomical scissiparity) and therefore presents a great aptitude for regeneration, especially at its cephalic part. The regeneration is achieved after 7 days (20 °C) and goes through eight characteristic stages (even if the sectionning was artificially induced). First, cephalic regeneration perturbations induced by copper, lead or platinum were tested. The subacute concentrations of he three metals induced a delay in cephalic regeneration. In addition, Pb and Pt treatments can cause atypical regenerations as compared with control (clear water regenerates) which are described in this paper. Worms arc intoxicated by water samples from well known heavy metal polluted sites. Toxic concentrations are sublethal but induce strong cephalic regeneration perturbations. Worm cephalic regeneration sensitivity to heavy metal pollution remains to be directly tested in the environment in order to qualify as an ccotoxicological test.