ABSTRACT
Agricultural activities and human industrialization are mainly responsible for the release of heavy metals into the environment, especially the air and the water. The first step towards the effective management of water resources is the assessment of pollution levels. Biosensors for the detection of pollutants in the environment can complement analytical methods by distinguishing bioavailable from inert, unavailable forms of contaminants. A bioassay system for detecting heavy metals in water using bioluminescent bacteria, Vibrio harveyi and Vibrio fischeri has been developed, which offers the advantages of simplicity and rapidity for screening heavy metals in water sources. Bioluminescence was found to be species specific and strain specific. Mercury, zinc and copper showed definite microbial toxicity and inhibition of bioluminescence. The inhibition range for each strain of a species was standardized and its reproducibility verified. The utility of the biosensors to detect heavy metals in tap water was demonstrated with samples supplemented with Hg (II).