1 research outputs found
Management of a Toxic Cyanobacterium Bloom (<i>Planktothrix rubescens</i>) Affecting an Italian Drinking Water Basin: A Case Study
An extraordinary bloom of <i>Planktothrix rubescens</i>, which can produce microcystins (MCs), was observed in early 2009
in the Occhito basin, used even as a source of drinking water
in Southern Italy. Several activities, coordinated by a task force,
were implemented to assess and manage the risk associated to drinking
water contaminated by cyanobacteria. Main actions were: evaluation
of analytical protocols for screening and confirmatory purpose, monitoring
the drinking water supply chain, training of operators, a dedicated
web site for risk communication. ELISA assay was considered suitable
for health authorities as screening method for MCs and to optimize
frequency of sampling according to alert levels, and as internal control
for the water supplier. A liquid chromatography-tandem mass spectrometric
method able to quantify 9 MCs was optimized with the aim of supporting
health authorities in a comprehensive risk evaluation based on the
relative toxicity of different congeners. Short, medium, and long-term
corrective actions were implemented to mitigate the health risk. Preoxidation
with chlorine dioxide followed by flocculation and settling have been
shown to be effective in removing MCs in the water treatment plant.
Over two years, despite the high levels of cyanobacteria (up to 160
× 10<sup>6</sup> cells/L) and MCs (28.4 μg/L) initially
reached in surface waters, the drinking water distribution was never
limited