This paper describes the development of an automated Flow Injection analyzer for water toxicity assessment. The analyzer is validated by assessing the toxicity of heavy metal (Pb(2+), Hg(2+) and Cu(2+)) solutions. One hundred μL of a Vibrio fischeri suspension are injected in a carrier solution containing different heavy metal concentrations. Biosensor cells are mixed with the toxic carrier solution in the mixing coil on the way to the detector. Response registered is % inhibition of biosensor bioluminescence due to heavy metal toxicity in comparison to that resulting by injecting the Vibrio fischeri suspension in deionised water. Carrier solutions of mercury showed higher toxicity than the other heavy metals, whereas all metals show concentration related levels of toxicity. The biosensor's response to carrier solutions of different pHs was tested. Vibrio fischeri's bioluminescence is promoted in the pH 5-10 range. Experiments indicate that the whole cell biosensor, as applied in the automated fluidic system, responds to various toxic solutions.
Keywords: Vibrio fischeri; flow injection; toxicity.