No abstract

No abstract

Hepatotoxins from blue‐green algae are increasingly recognized as a potential hazard in drinking water supplies. The clinical consequences of ingestion include acute or chronic liver injury, with the possibility of enhanced susceptibility to, and growth of, liver tumors. To establish guidelines for water safety requires the demonstration of dose‐dependent effects of toxicity and experimental determination of maximum “no‐adverse‐effect levels.” This paper describes the use of growing pigs as a model for human injury resulting from Microcystis toxins in drinking water. Risk assessment calculations using a series of safety factors are carried out, resulting in a guideline level after incorporating an additional safety factor for tumor promotion of approximately 1.0 μg toxins/L. With the Microcystis used for this trial, that concentration corresponds to 5000 cells/mL. © 1994 by John Wiley & Sons, Inc..

Cyanobacteria (blue‐green algae) produce toxins and tastes and odors that can significantly impair water quality. The removal of cyanobacterial cells without cell damage could significantly reduce the concentration of tastes, odors, and toxic cell metabolites present in treated water. Cultured cyanobacterium, hepatotoxic Microcystis aeruginosa, was mixed with reservoir water to simulate water entering a treatment plant during an algal bloom. A bench‐top jar‐test apparatus (flocculation) and a full‐scale pilot plant (flocculation–sedimentation–filtration) rated at 600 mL/min were used to evaluate the effectiveness of conventional water treatment processes in removing cyanobacterial cells. Removal of cells by flocculation using a jar‐test apparatus with aluminum sulfate dosed at concentrations used in water treatment practice varied between 70 and 83%. Results obtained from the pilot experiment indicated 99.9% of the cells were removed. More important, no additional release of microcystin (toxin) was found in the finished water.

No abstract