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-Excit ed 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 l abware. Lead concentrations were determined by direct analysis of 20 m ul water samples without any preconcentration steps, which are require d by traditional analytical methods. Pb profiles were generated for nu merous 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 re cent data reported using graphite furnace atomic absorption spectropho tometric methods and clean room practices, but are much smaller than h istorical data generated by atomic absorption spectrophotometric-solve nt extraction techniques. These latter data are most probably biased h igh as they were generated under less than ideal conditions using unpr oven sample handling techniques and insensitive analytical methods.