Determination of the heavy metal binding capacity of aquatic samples using MetPLATE: a preliminary study

MetPLATE, a microbial toxicity test which is specific for heavy metal toxicity, was used to rapidly determine the heavy metal binding capacity (HMBC) of a wide range of surface waters from Florida and Georgia. HMBC determines the impact of physicochemical factors on metal bioavailability and toxicity. The new developed protocol, using MetPLATE as the toxicity assay, showed that HMBC varied from 1.7 to 39.2 for Cd whereas the ranges for Cu and Ag were < 1-11.9 and < 1-2.1, respectively. The effect of seasons on HMBC was determined using samples from the Hogtown Creek, Gainesville, FL, and from the St John's river in Jacksonville, FL. Both surface waters displayed the highest HMBC during the Fall season. Preliminary examination of the limited data set confirms that HMBC may be influenced by the concentration of dissolved organic carbon (DOC). These preliminary data show that the impact of physical and chemical parameters on the toxicity of metals in aquatic environments can be rapidly assessed using rapid and low-cost microbiotests.