US EPA

Environmental Applications of Novel Instrumentation for Measurement of Lead Isotope Ratios In Atmospheric Pollution Source Apportionment Studies

EPA Grant Number: R826177
Title: Environmental Applications of Novel Instrumentation for Measurement of Lead Isotope Ratios In Atmospheric Pollution Source Apportionment Studies
Investigators: Keeler, Gerald J. , Graney, Joseph R. , Halliday, Alexander N.
Current Investigators: Keeler, Gerald J. , Graney, Joseph R.
Institution: University of Michigan , The State University of New York at Binghamton
EPA Project Officer: Shapiro, Paul
Project Period: December 1, 1997 through November 30, 1998
Project Amount: $99,776
RFA: Exploratory Research - Environmental Chemistry (1997) RFA Text |  Recipients Lists
Research Category: Water , Land and Waste Management , Air , Engineering and Environmental Chemistry

Description:

In spite of the reduced flux of lead to the atmosphere from the combustion of leaded gasoline, anthropogenic sources still dominate the supply of lead to the atmosphere and the environment. Emissions from coal and oil combustion, industrial processes, and municipal incineration will all become more important in controlling the lead isotopic ratios in ambient air and precipitation in the future. The measurement of lead isotope ratios coupled with other trace element determinations on a spatial and temporal basis can potentially be used to differentiate between, and trace the local and regional movement of aerosols from these different sources of pollution. From samples of precipitation and ambient air collected under ongoing studies of Hg and trace element transport and deposition, the concept of using lead isotopes as a tracer will be tested on several scales: 1) locally, by focusing on an area with several well defined point sources (in the south Florida/Everglades region) and 2) over a larger geographic area, by examining regional versus urban influences in the Great Lakes region.

Approach:

The low concentrations of lead in precipitation and ambient air, the potential for contamination during sampling, and the time and expense involved in measuring isotope ratios to high precision are reasons why this tracer approach has not been used extensively to date. Through clean sampling techniques coupled with use of a hybrid instrument (the Plasma 54) it will be demonstrated that measurements of lead isotope ratios from samples with low concentrations can be time and cost efficient. The traditional method to measure isotope ratios to high precision involves thermal ionization mass spectrometry (TIMS) which is extremely costly and time consuming. The use of inductively coupled mass spectrometry (ICP-MS) to measure lead isotope ratios is an alternative to TIMS. High throughput and low cost are possible with this method, but quite often the precision of the ratios is not adequate to unambiguously define pollutant sources. To achieve high precision analyses and fast, cost efficient throughput, an instrument that combines the speed of ICP-MS with the precision of TIMS is needed, and the Plasma 54 is such an instrument.

Expected Results:

Results from measurement of lead isotope ratios will be directly coupled with those of Hg and other trace element concentrations and fluxes for a better understanding of source/receptor relationships. This approach will allow development and testing of models to apportion deposition from different sources of pollution. Such identification of principal sources of pollutants in precipitation and ambient air is important in terms of designing effective control strategies and in understanding the transport of air pollutants from local and regional emission sources.

Publications and Presentations:

Publications have been submitted on this project: View all 4 publications for this project

Supplemental Keywords:

ambient air, precipitation, particulates, heavy metals, atmospheric transport, environmental chemistry, geology, geochemistry, analytical, measurement methods, lead isotope ratios, Great Lakes, Midwest, Florida, transportation, industry, RFA, Scientific Discipline, Air, Geographic Area, particulate matter, Ecology, Environmental Chemistry, Chemistry, State, mobile sources, Engineering, Chemistry, & Physics, Great Lakes, ambient aerosol, particulates, precipitation, atmospheric particles, aerosol particles, air quality models, tracer isotopes, air sampling, municipal incineration, lead isotope ratios, combustion, Florida, acid rain, atmospheric deposition, FLA, source apportionment studies

Progress and Final Reports:

1998 Progress Report
Final Report