Lead stable isotope ratios as indicators of soil age and human impacts

Lead (Pb) isotope ratios can often be used to trace sources of Pb in soils and water.   207Pb/206Pb and other Pb isotope ratios differ between the various sources of Pb in the environment.  For example, Pb deposited during the use of Pb gasoline additives often has distinctive Pb isotope ratios that can used to distinguish it from ordinary, naturally occurring Pb in soils.

This project aims to use Pb isotopes to trace the appearance of industrial Pb in soils close to Champaign-Urbana (in the “Critical Zone Observatory”).  The focus is not on Pb contamination; we seek to use the appearance of industrial Pb as an indicator of soil and sediment age- to distinguish pre-1940 soils from more recent ones.

This project involves:

  1. Lab work to implement methods for extracting and purifying Pb from soils and measuring Pb isotope ratios using the Multicollector ICP-MS.
  2. Measuring a series of soils.
  3. Interpreting results using information in the scientific literature regarding Pb isotopes in industrial emissions over time.

This could be either a senior thesis project or an undergraduate research project.

Supervisors:  Dr. David Grimley (ISGS), Prof. Tom Johnson, Dr. Gideon Bartov (Lab Manager)   contact:  tmjohnsn@illinois.edu