An algal biosensor for the monitoring of water toxicity in estuarine environments.

An algal biosensor for toxicity assessment of estuarine waters is proposed. The sensor was obtained by coupling a suited algal bioreceptor (the cyanobacterium Spirulina subsalsa) to an amperometric gas diffusion electrode. The analytical device allows the monitoring of the evolution of photosynthetic O2 and the detection of alterations due to toxic effects caused by environmental pollutants present in the medium. Four chemical species representative of three main different classes of pollutants (heavy metals, triazinic herbicides, carbamate insecticides) were tested at different concentrations using a standardized natural water as experimental medium. In all the cases a toxic response was detected (i.e. a dose-related inhibition of photosynthetic activity was recorded) with good reproducibility.