An integrated optical multisensor for organic pollutants has been realised, and characterised for a single analyte. The sensor exploits fluorescence immunoassay in the evanescent field of channel waveguides to enable rapid, simultaneous and high-sensitivity fluorescence detection of up to 32 pollutants in water. The chemical modification used to render the surface specific to analytes allows automatic regeneration for immediate reuse. The system has been demonstrated for the key pollutant estrone and a detection limit below 1 ng/L has been achieved.