Performance of current XRF instrumentation for measuring the lead content of environmental samples Kate McIntosh Wadsworth Center, NYSDOH LCC Workshop June 8, 2012

Outline Background X-Ray Optical Systems and Monochromatic XRF (M-XRF) Lead in painted toys and consumer products Instrumentation XOS HD-Prime Thermo Scientific Niton XL3t Inter-laboratory study and reference materials Lead in household paint Screening with the XL3t Conclusions and summary recommendations Future work XOS Personal Environmental Analyzer (PEA)

X-Ray Optical Systems Industry collaborator Leader in development and manufacture of x-ray optics Interest in developing new technologies for environmental applications Prototype instruments based on monochromatic XRF (M-XRF) for specific public health problems Advantages: Reduced background provides improved P/B and greater sensitivity No loss in intensity due to scatter in filter, so low power sources can be used East Greenbush, NY X-Beam® Doubly Curved Crystal (DCC) optic

Lead in painted toys and consumer products

XOS HD-Prime Dimensions: 36x26x32 inches Weight: 240 lbs cameras sample chamber Calibration modes: Plastic, metal, wood, glass, rubber, leather, textiles, bulk paint For painted products: 1)Measure painted region 2)Measure substrate ≤7 minutes 1 mm spot size 50 kV, 2 mA maximum Mo anode; 7, 17.5, 31 keV DCCs; SDD

Thermo Scientific Niton XL3t Purchased in 2009 to evaluate side-by-side with M-XRF Calibration modes Metals (%) Soil (mg/kg) Filters (µg/filter) Plastics (mg/kg) Painted products (µg/cm 2 ) Reports >30 elements Dimensions: 9x9x4 inches Weight: <3 lbs ≤2 minutes 50 kV, 40 µA maximum Au anode; SDD 3-8 mm spot size

Lead in toys Consumer Product Safety Improvement Act (CPSIA) of 2008 New regulations for products intended for children <12 years old 2 µg/cm 2

Reporting units for lead in paint 90 mg/kg (ppm) is the CPSC limit required to demonstrate compliance with CPSIA Basis in bio-kinetic model of lead exposure in children Previous 600 mg/kg limit related to 300 µg Pb/day expected to keep BLL <40 µg/dL 2 µg/cm 2 is intended as a screening limit for small painted areas (<1 cm 2 or 10 mg) Industry consensus value, scientific basis uncertain Appears widely used 2 µg/cm 2 ≅ 90 mg/kg??

ASTM/XOS Interlaboratory Study Goal - precision statement for ASTM F2853, a standard (CPSC approved) method for determination of lead in paint layers by M-XRF (HD-Prime) “Repeatability” 26 mg/kg at 90 mg/kg “Reproducibility” 35 mg/kg at 90 mg/kg N = 9 labs: Wadsworth; NIST; 5 testing labs; Mattel; XOS 40 test samples distributed Bulk substrate CRM/RMs Metal, glass, wood, plastics Paint film on substrate RMs 5 µm and 30 µm thickness Retain samples for further assessment

Painted-surface RMs on HD-Prime Each of these samples (n=10) ND with the XL3t, 5 false negatives Error bars ±SD, n=10 Reference 50 mg/kg HD-Prime 52±6 (4% bias) LOD (mg/kg) HD-Prime 17

Comparing XRF area concentrations with mass fractions determined by AAS Error bars ±SD, n=10 30-µm paint on PVC FP

Assessment with SRM 2569 Lead Paint Films for Children’s Products Released by NIST in 2011 Certified in both mg/kg and µg/cm 2 units Does not report in mg/kg n= g/cm µm LOD 16 mg/kg LOD 0.03 µg/cm 2 LOD 0.13 µg/cm 2 Certified values in µg/cm 2 are well below threshold Non-representative matrix

Lead in household paint

Screening paint chips with the XL3t Ex-situ XRF could provide an alternative means of identifying LBP Preliminary assessment completed using NIST Powdered Paint SRMs and routine samples received at Wadsworth n=7, 60 s measurement time Samples measured as received in plastic bag

Screening paint chips with the XL3t n=53 samples, 60 s measurement time

Conclusions & summary recommendations Determination of lead content in paint on toys is a very difficult analytical problem (+) XRF nondestructive nature & ability to test small areas/substrate The XL3t is of limited use for determination of lead in painted toys, given false negatives for non-PVC substrates Shows promise for ex-situ identification of LBP Though the HD-Prime is approved for certifying compliance & reported no false negatives, quantitation at 90 mg/kg may be unreliable due to uncertainty in the “real world” LOD. CPSC should consider reducing the 2 µg/cm 2 limit NIST should produce SRMs more representative of painted toys HUD/EPA should re-evaluate the 0.5 wt% limit as well as the screening methodologies for LBP

Future Work Begin field evaluation of an M-XRF prototype intended for multi-element analysis Characterizing the elemental content of materials in personal environment is important for some public health studies as it helps identify possible sources of exposure R01 funding from NIH to incorporate into an ongoing epidemiological study Focus on toxic elements Compare performance to existing technology Sensitivity, accuracy, fitness-for-purpose

XOS PEA β- prototype Large sample chamber Dimensions: 15x18x18 inches Weight: 50 lbs Touch screen Pb, As, Hg, Cd, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Br, Rb Sr, Ag, Sn, Sb, Ba, Au, Tl, Bi 50 kV, 1 mA maximum Mo anode; 7, 17.5, 31 keV DCCs; SDD 4 minutes

Lead content in Indian spices Error bars (XRF) ±SD, n=3, (ICP-OES & FAAS) ±10%, n=1 Chili powder Screening in bag, PEA 130±9 mg/kg 30% bias Turmeric

Screening of routine samples Identified possible additional health risk (<5 min) Physician notified Herbal medicine product submitted as part of a lead- poisoning investigation Error bars (XRF) ±SD, n=3, (ICP-OES) ±10%, n=1

Acknowledgements Dr. Patrick Parsons, and the Laboratory of Inorganic and Nuclear Chemistry (LINC) at the Wadsworth Center, NYSDOH John Orsini of LINC/NYSDOH XOS Funding: XOS SBIR from NIH NIEHS 5R44ES016689