Toxicity assessment of organic pollution in wastewaters using a bacterial biosensor

A cost-effective strategy using an amperometric biosensor with Escherichia coli that provides a rapid toxicity determination of wastewaters is described. This Cellsense biosensor system comprises a biological component (E. coli) immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal. The electrical signal can subsequently be amplified, stored and displayed. This work using a whole bacterial biosensor system studied the E. coli responses to commonly detected compounds in textile and tannery wastewaters, such as phenolic compounds, non-ionic surfactants, and benzene sulfonate compounds. Chemical analysis was performed by sequential solid-phase extraction (SSPE) followed by liquid chromatography-mass spectrometry (LC-MS). The 50% effective concentrations (EC50) values were determined for every standard substance and were converted to toxicity units (TU). The Cellsense system was applied to real-world environmental samples of influent and effluent wastewater treatment works (WWTW) in Catalonia (Spain), with one WWTW receiving industrial tannery wastes, and untreated textile wastewater-from Porto(Portugal). The toxicity units were also calculated for the samples giving positive responses to the toxicity to the Cellsense system and permitted to establish the pollutants responsible of the observed toxicity. (C) 2001 Elsevier Science B.V. All rights reserved.