SELECTIVE ASSAY FOR HEAVY METAL TOXICITY USING A FLUOROGENIC SUBSTRATE—Short Communication

Abstract

Abstract-Chromogenic substrates have been generally used in enzymatic assays for the specific determination of heavy metal toxicity. A toxicity assay based on the specific inhibition of ␤-galactosidase by heavy metals and using a fluorogenic substrate was evaluated for its sensitivity to heavy metals and organic toxicants. The toxicity assay, FluoroMetPLATE, was specific for heavy metals and was more sensitive than the widely used Microtox assay. Except for lead, our assay displayed sensitivity similar to that of the 48-h acute Ceriodaphnia dubia assay. Monitoring of industrial samples showed that the FluoroMetPLATE assay gave similar results as the daphnid toxicity assay for 22 of 29 samples. For the remaining samples, for which there was no agreement between the two tests, it was found that the toxicity was mostly due to organic toxicants, confirming the specificity of FluoroMetPLATE for heavy metal toxicity.