XRF Instrument

 Saint Mary's College purchased a Niton 796 XLt instrument through a grant from the Dreyfus Foundation in 2004. This field portable XRF instrument has been integrated into the curriculum and is utilized in faculty and student research projects. The School of Science Advisory Board provided funding to support an upgrade in 2017.  The new XRF is a ThermoNiton XL3t and a photo is at the bottom of this page.

  Fall 2006 Environmental Chemistry students record spectral data at highway 24 field site.


Environmental Chemistry students have sampled soils near an urban highway and quantifed lead content in soil as a training lab. After the training lab, some classes have performed screening studies at other sites to benefit various community organizations.

  • Soil Screening

Quantifying Lead

Student become familiar recording spectral data at field site adjacent to Highway 24.   Lead content in soil samples are reported to Cal-Trans after every class performs a site screening experiment.

Each course has a separate additional site where students perform soil screening analysis.  The soil samples are either analyzed in the field or collected a spectral analysis occurs in our labs.  The locations range from a residential area where the age of the housing stock is likely to have lead based paint, a proposed community garden site and salt marsh where lead exposure to an endangered species may drive clean up activities.

A residential site screening experiment was written up as a formal lab experiment and published by the Journal of Chemical Education 2008, 85(7), 980-982.

One chemistry major has performed an independent research project on soil samples provided from Alameda County  validating the student's ablitiy following EPA Method 6200.

Students in the Environmental Chemistry lab gain skill with the instrument and general aspects of field sampling.  The Gateway Highway 24 Interchange site has been sampled in Spring 2003, Fall 2004, Fall 2006, Fall 2008, Fall 2012, and Fall 2014. 

This field site is changing as Cal-Trans upgrades Highway 24.  The dynamic changes are investigated in the lab.

The collection of soil core is underway at the present time and the experimental results will hopefully yield some useful trends.

Quantifying Arsenic

An opportunity to study arsenic in soils is being developed.  If samples don't contain lead as an analyte, then the quantification of arsenic should be straightforward.  A few field investigations are being planned.

  • Other Mediums

Dust Wipe analysis

Some preliminary samples were collected in a residence and supported the soil study where lead from old paint was identified.  The dust wipe samples may be sent to colleagues as a sample to further validate our use of dust wipes in the curriculum.  To use dust wipes, a confirmatory method of analysis is critical and a  partnering institution will be necessary.


ThermoNiton XL3t instrument

This instrument has an integrated color PDA and GPS, plus and on board camera to clearly identify surfaces studied.