The project is finalised to the introduction of a new technique for water quality monitoring, able to substantially improve the knowledge of environmental conditions. The innovative principle is the use as sensors of living organisms and the real-time check of their functional conditions by a non-invasive technique. In fact it implies the measurement of the ultra-weak delayed photoluminescence parameters, that are sensible indicators of the biological system functional status.The living organisms are unicellular algae, the photoluminescence of which is influenced by the quality of the liquid in the solution where they live. The status of the biological system is detected by a transducer and transformed in an electromagnetic signal, further elaborated and analysed by standard techniques. The technique appears promising as it is strongly a-specific, i.e. it responds to a large range of possible contaminants, allowing a quick quality control. Moreover, using some typical indexes related to the luminescence decay curve parameters, it gives information on several types of possible contaminants, orienting the analyst's further work towards the determination of single contaminant concentrations by classical methods. Preliminary work show that delayed luminescence emitted from microalgae is influenced by the presence of weed killers, as atrazine, and heavy metals in their culture medium.