XRF Applications on

Native American CollectionsCheryl Podsiki

The Field Museum, Chicago

Symposium School for Advanced Research

Indian Arts Research Center, Santa Fe, NM

May 28, 2009

Applications

Manufactured for use in Environment: Soil samples Modern Metal Alloys: Scrap metal industry Analytical Standards

Adapted for use by Health Department: Lead paint, asbestos, plastics, electronics, toys, pesticides

Museum Collections and Research: Metal alloys, glass, ceramics, obsidian, minerals, pigments, paints,

mordents, textiles, paper, leather, hide, skin, fur, felt, feathers, shell, bone, ivory, plastic, minerals, geological specimens, taxidermy specimens, pesticides

Conservation Use in Collections

Bruker-AXS Tracer III-V analyzer, Rhodium source

Analysis of unknown residue

Pesticide Check

Pigment identification

Glass: Lead

Archaeological Field Work

Innov-X Alpha Series, Tungston source

Portable XRF for floor chemistry

Lab set-up for obsidian

Archaeological Metals

Wari Tupu AD 600-1000 LA-ICP-MS : Cu 97.50 and As

1.98%

Hopewell Antler Headdress: Native Copper; Reconstructed

for WCE, 1893, using iron based metal rods, plaster, pigments,

adhesive; Subsequent conservation repairs used wood

dowels, more pigments, different adhesives.

Lead top to condiment bottle; early 20th century.

XRF

Confirmation of Lead

Glass Eyes

Buddha face gesso / wood (red) over glass

eye (blue).

33 kV; 2.20 µA; Titanium-Aluminum filter; no vacuum; 60 seconds.

Archaeological glass, Glass Beads, Ceramics, Obsidian,

Chert

Glass beads from Kenya analyzed with LA-ICP-MS;

XRF

Cadmium, Zinc, Arsenic, Lead

Cadmium, Zinc

Cadmium, Zinc

Lead, Arsenic

Lead, Arsenic

Elements Detected by XRF

As

Hg Pb

**

*

*

* *

*

*

Heavy Metal Pesticide Residues

Detected • Arsenic compounds [inorganic]• Lead or lead compounds [inorganic]• Mercury compounds [likely inorganic, possibly

organic]• Zinc compounds [inorganic]

• Ethylene bromide (bromine residue remains) • Ethylene dibromide [fumigant] (bromine residue

remains) • methyl bromide (bromine residue remains) • Methylene bromide [halogenated hydrocarbon]

(bromine residue remains)

Spot Tests

Merckoquant Arsenic Test

Mercury Indicator Powder Slide Test

Plumblesmo Test for Lead

XRF Analyses with Zuni Tribal Representatives

Testing Process: options, flexibility•Short Pre-test Visit by Tribal Representatives

to Museum

Cultural handling, restrictions, issues, concerns

Tribal reason (s) for test: use, retire, storage

Basic methodology for using XRF

Documentation requested by Tribe and by Museum

•Longer Visit for purpose of conducting XRF analysis together

*Discuss issues connected to XRF analysis

Better idea of sample sites and documentation needed

•Museum staff completes testing and final documentation

•Visit by museum staff to tribal community to present and discuss results/demonstrate XRF analyzer.

Mapping Sample Sites

1 23

1

2 3 4

5 6 7

1

2

3

Mapping and Results Documentation

1

2

8

34

5

67

9

10

1112

Sample site Arsenic(As)*

Bromine(Br)

Lead (Pb)

Mercury (Hg)

1 broken blue beads

x nd x nd

2 red beads x nd x nd

3 yellow beads nd nd x nd

4 dark blue beads nd nd x nd

5 sky blue beads x nd x nd

6 pink beads x nd x nd

7 green beads nd nd x nd

8 buckskin toe, top

nd nd x nd

9 buckskin toe, bottom

nd nd x nd

10 red fabric lining

x nd x possible

11 buckskin heel, back

nd nd x nd

12 Tyvek insert support

nd nd nd nd

Test date: 2/10/2007 Instrument operator/handlers: Cheryl PodsikiInstrument: Bruker-AXS Tracer III-V analyzer Voltage (kV): 40 Current (μA): 8 Filter: Copper-Titanium- Aluminum Vacuum: No Acquisition time: 60 secondsTest Notes: The broken blue beads contain lead and arsenic, but the buckskin toe # 8 showed only a comparative trace of lead (likely from cross-contamination of bead residue) and no arsenic. Readings taken from the toe, heel, and bottom of the buckskin showed the same results. The presence of arsenic is likely from glass composition and not from pesticide. The Tyvek support was checked for cross-contamination purposes.

Continued Care

Pesticide or Inherent?

The blue beads are deteriorating due to glass disease. Glass residue is present in the housing container and on the bottom surface of the moccasin.

Spectra overlay of Buckskin and Beads

The broken blue beads (blue spectrum) contain lead and arsenic. The top of the buckskin toe (red spectrum) exhibits very little lead and no arsenic. It is likely that the presence of lead and arsenic is due to glass manufacture and not pesticide.

Cinnabar/Vermilion

Rare red Chinese paper rubbings, Laufer collection, 1900-1910. Vermilion Red Lead Realgar (mercury) (arsenic)

Pigments on Objects

Blue spectrum is the red pigment; red spectrum is the bare wood.

Lead

Mercury

Red pigments tested

Blue spectrum is the red pigment; red spectrum is the bare wood.

Brown Feather. 40Kv; 8µA; Copper-

Titanium-Aluminum filter; no vacuum; 180 seconds.

Seed bead and feather necklace

from South America

Feathers

Wood Box

Box exterior (red) over interior (blue). 40Kv; 8µA; Copper-

Titanium-Aluminum filter; no vacuum; 60 seconds.

Red Pigmented Buckskin Pouch

Exterior (red) over Interior (blue). 40Kv; 8µA; Copper-Titanium-Aluminum filter; no

vacuum.

Exterior front center (red) over interior front center (blue). 40Kv; 8µA; Copper-Titanium-Aluminum filter; no

vacuum; 60 seconds. Spot test for arsenic was positive.

Buckskin Ceremonial Item

Natural Pigments: Two Yellows

Two yellow pigments: Sample 10, a calcium based pigment, (blue spectrum), exhibits a significant arsenic peak compared to Sample 11, a silicon based pigment (red spectrum), which exhibits a much lower arsenic peak.

Natural Pink Pigment

The silicon and iron based pink pigment exhibits a fairly significant arsenic peak. Results of laser-ablation (LA-ICP-MS) analysis show 698 ppm arsenic in this sample.

Issues encountered Museum• Field Museum has massive collections with wide range of

materials but resources are lacking for further research/experimentation: funding, staff, department priorities – same problem as in other non-university museums and smaller institutions

• Isolation of issues unless network with other users• Practice and experience is a must for interpretation; lack

of resources for support.

XRF• Spectral interference• Interpretation: subjective; two people needed• Need “standard” reference materials to provide semi-

quantitative results• Results: even semi-quantitative or quantitative results

cannot answer the ultimate question: “What does it mean?” Must get medical community involved.

Cultural representatives – cultural, spiritual, legal

Conservator/collections manager – past and present museum procedures and object history; material characterization; conducts test; interprets results

Analytical chemist or physicist – primary or secondary interpretation of results; conducts test

Medical / health professional such as a toxicologist, industrial/occupational hygienist – safe handling guidelines; health effects

Manufacturer scientist of specific instrument – shares pertinent information about instrument and known applications; R & D to continue development of needed technology for museum application

Wider circle of XRF users/institutions – network; share information; research; beginners, previous users and experts

Team approach

“The issues are complex and resources too little – an information network among XRF

users and institutions is vital to finding solutions.”

Participants, 2008 XRF Seminar at The Field Museum