Native Collections and Pesticides: Testing, Analysis, and Mediation

Speakers: Nancy Odegaard, PhD, Cheryl Podsiki, and Özge Gençay Üstün

Symposium, Indian Arts Research Center (IARC)

Thursday, May 28, 2009, 10:00 am–4:00 pm

Conservator Cheryl PodsikiConservator Cheryl PodsikiConservator Cheryl Podsiki (Department of Anthropology, Field Museum) analyzing material culture with a portable XRF device.
SAR Symposium: Native Collections and Pesticides: Testing, Analysis, and Mediation.
Conservator Cheryl PodsikiConservator Cheryl Podsiki (Department of Anthropology, Field Museum) analyzing material culture with a portable XRF device.
SAR Symposium: Native Collections and Pesticides: Testing, Analysis, and Mediation.

The Indian Arts Research Center (IARC) at SAR hosted the symposium, Native Collections and Pesticides: Testing, Analysis, and Mediation, on May 28, 2009, which featured three conservators from major museums in the United States. Nancy Odegaard, Head of Conservation at the Arizona State Museum; Cheryl Podsiki, Conservator in the Department of Anthropology at the Field Museum; and Özge Gençay Üstün, Conservator at the Southwest Museum, Autry National Center shared important educational information about pesticides use and testing for pesticides on objects in museum collections.

The highlight of the symposium was a demonstration of portable X-ray fluorescence spectrometry (XRF). Portable XRF is a handheld device that can be easily transported to collections to test for the presence of toxic heavy metals that were once commonly used as pesticides. Cheryl Podsiki provided the instrument and conducted the demonstration. She tested several items to help illustrate the spectra the tests produce depending on the type of heavy metal detected.

Due to the interest in the symposium and presentations, the conservators’ presentations are provided here along with abstracts of their presentations and their biographical profiles.

Download the Native Collections and Pesticides Symposium flier (PDF, 140 KB).

Presentation Abstracts:

A General Overview of Pesticides, Testing, Mitigation, and Removal
Nancy Odegaard
Arizona State Museum

Pesticide residues on museum objects are a legal, moral, and health issue for museum professionals and tribal communities. Recent research efforts have been made to devise more efficient ways to monitor and characterize pesticide contaminants. Approaches to understand historic uses of pesticides, to test for residues, and to develop strategies for removal were discussed.

View the PowerPoint presentation (Adobe PDF):
A General Overview of Pesticides, Testing, Mitigation, and Removal by Nancy Odegaard (PDF, 23 MB)

Portable XRF Demonstration with Cheryl PodsikiPortable XRF Demonstration with Cheryl PodsikiPortable XRF Demonstration with Cheryl Podsiki

XRF Applications on Native American Collections
Cheryl Podsiki
The Field Museum, Chicago

This presentation reviewed XRF applications presently used on collections in the Department of Anthropology at The Field Museum, with a focus on detecting heavy metal pesticides. Collaboration with Native American tribes involved in the testing process was highlighted throughout.

Conservators at The Field Museum have been using a Bruker-AXS Tracer III-V X-ray fluorescence (XRF) analyzer since 2006 to determine material composition of objects in preparation for appropriate treatment, exhibition, or storage, and to determine the presence of heavy metals derived from natural pigments, manufacture, and pesticides. At present, all spectra are reviewed and interpreted manually by an experienced conservator and an analytical scientist or physicist to provide qualitative results obtained from testing organic materials such as buckskin, textiles, or feathers.

Use of the XRF on Native American collections, especially on those considered ceremonial or sacred, has changed the manner in which Anthropology collections at the museum are being tested and the way in which results are being documented. Equally important to the testing methodology is the fact that tribal representatives are encouraged to participate in the testing process. Collaboration among the team members has led to an exchange of important cultural and scientific information about the care of the collections and a better understanding of the challenges involved in determining the presence of pesticides and the limitations of XRF for quantifying risks associated with heavy metal poisons. Pertinent information provided to tribes includes general and museum-specific pesticide uses, current mitigation techniques and research, customized safe-handling guidelines, and resource lists for medical and environmental agencies.  

View the PowerPoint presentation (Adobe PDF):
XRF Applications on Native American Collections by Cheryl Podsiki (PDF, 10 MB)

Portable XRF: Bruker Tracer III-VPortable XRF: Bruker Tracer III-VPortable XRF: Bruker Tracer III-V

Limitations of Handheld XRF Instrument as a Quantitative Tool for Analyzing Heavy Metal Pesticides on Organic Art Objects
Özge Gençay Üstün
The Southwest Museum, Autry National Center

This presentation demonstrated some of the many factors that complicate the quantitative analysis of heavy metal pesticides, i.e. lead, arsenic, and mercury compounds on organic objects with handheld X-ray Fluorescence (XRF) analyzers. It must be emphasized that there are limitations of the instrument, in particular quantification of the elemental concentrations. Therefore, sources of errors affecting the quantitative results must be taken into account. A few of these factors include environmental conditions such as relative humidity and temperature, properties of the substrate (e.g. density, geometry), the instrument's detection limit of the metal of interest, and interferences from other elements. This study highlights how object geometry, depth of penetration, and interferences by other elements affect the analyses by an Innov-X handheld XRF analyzer. As demonstrated so far, these instruments are helpful in the identification of heavy metals on ethnological museum artifacts. However, they should only be used in a semi-quantitative capacity, and the proper quantification of heavy metals may be best carried out using other analytical techniques.

View the PowerPoint presentation (Adobe PDF):
Limitations of Handheld XRF Instruments by Ozge Gencay Ustun (PDF, 2 MB)

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