Chemicals used to control phytoplankton blooms induce the release of phytotoxins that increase the potential health risks in drinking water supplies.
To test this hypothesis, the effects of six chemical treatments on the release of the cyanobacterial toxin, microcystin-LR from freshly collected phytoplankton were examined in laboratory experiments.
In addition, the integrity of a chemically-treated culture of Microcystis aeruginosa was examined by both a scanning electron microscope and a transmission electron microscope.
Chemicals which control cyanobacterial blooms through inhibition of cell functions appeared to induce cell lysis and subsequently increased dissolved MCLR concentration in the surrounding water.
In contrast, both lime and alum treatment controlled the cyanobacterial blooms mainly by cell-coagulation and sedimentation, without any (lime) or only little (alum) increase in dissolved MCLR concentration in the water.
In contrast, x =39% of the MCLR remained in decaying phytoplankton for up to 26 d, therefore it is likely that MCLR would persist and decay inside the lime or alum coagulated Microcystis cells, before being released into the surrounding water phase.
For these reasons, lime or to a lesser extent alum, appears to be more suitable than either algicides or chlorine for the control of microcystin-containing cyanobacterial blooms in drinking water.
Mots-clés Pascal : Composé chimique, Lutte chimique, Bloom, Phytotoxine, Pouvoir pathogène, Traitement eau potable, Homme, Toxicité, Foie, Microcystis aeruginosa, Cyanobacteria, Bactérie
Mots-clés Pascal anglais : Chemical compound, Chemical control, Bloom, Phytotoxin, Pathogenicity, Drinking water treatment, Human, Toxicity, Liver, Microcystis aeruginosa, Cyanobacteria, Bacteria
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0398087
Code Inist : 002B30A02A. Création : 01/03/1996.