APPLICATION OF LASER-EXCITED ATOMIC FLUORESCENCE SPECTROMETER TO STUDY LEAD DISTRIBUTION IN GREAT-LAKES WATERS

This paper reports for the first time the application of a Laser-Excited Atomic Fluorescence Spectrometer (LEAFS) to study lead distribution in the Great Lakes waters. A class 100 clean laboratory for in-house work and a portable clean lab for field work were used for all sample handling, and an exhaustive cleaning procedure was used to clean all labware. Lead concentrations were determined by direct analysis of 20 mul water samples without any preconcentration steps, which are required by traditional analytical methods. Pb profiles were generated for numerous stations showing relatively high concentrations in the Niagara-Hamilton-Toronto region of Lake Ontario. The average concentrations of dissolved lead were found to be 25 ng/l for Lake Ontario, 9 ng/l for Lake Erie and 4 ng/l for Lake Superior. They are comparable to some recent data reported using graphite furnace atomic absorption spectrophotometric methods and clean room practices, but are much smaller than historical data generated by atomic absorption spectrophotometric-solvent extraction techniques. These latter data are most probably biased high as they were generated under less than ideal conditions using unproven sample handling techniques and insensitive analytical methods.