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Health Effects, Consumer, Indirect and Occupational Exposure in the Pb RA C. Boreiko ICF 8 – 11 October 2005
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Topics Evaluation of the health literature Consumer exposure scenarios for crystal Indirect exposure (local sources) Occupational exposure Implications for the crystal industry
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Health Literature Focused upon ~1,200 key human health papers selected from more than 9,000 considered Where possible used “consensus” documents to summarize older literature and for background information ATSDR Toxicological Profile for Lead IPCS Lead EHC Primary emphasis on evaluating primary literature for health effects critical for Risk Characterization Use quality scoring to support conclusions and “weight of evidence” evaluations
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Health Issues Evaluated Heme (aenemia) Renal Neurological (adult) Fetal Development Cancer Reproduction Endocrine Excretion Blood Pressure Pb Poisoning Child Development Genotoxicity Immune Uptake Toxicokinetics
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NOAEL’s for Different End Points Health EndpointHu StudiesNOAELExposed Population Renal system effects> 4060 μg/dLAdult, all Haematological effects> 5050 μg/dLAdult, all Reproductive effects>2745 μg/dLAdults, male Nervous system effects>14040 μg/dLAdults, all Reproductive effects>2230 μg/dLAdults, female Nervous system effects>3410 μg/dL Children Nervous system effects>1110 μg/dL Foetus (exposure during pregnancy)
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MOS MOS ref varies as a function of endpoint severity and scientific uncertainty Traditional sources of uncertainty include: Animal to human extrapolation Inter-individual variability in exposure or uptake Susceptible sub-populations Endpoints for NOAELS are subtle Uncertainty is reduced Human data Use blood lead (eliminates exposure/uptake variability) NOAEL’s for sensitive populations are identified Use of minimal MOS (1) in VLRA
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Crystal Product Evaluation Examined pattern of product use “Negligible exposure” by expert judgment if product use unlikely to yield exposure ISO standards noted as measure of product structural integrity Food contact items subjected to detailed analysis Typical exposure estimated Hypothetical worst case exposure constructed Exposure levels then compared to a series of exposure criteria
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Products Evaluated Decorative crystal objects Dermal exposure/transfer Negligible exposure assumed Flatware Food contact item Main use with dry foods Oral exposure principle route of concern Little opportunity for lead elution Negligible exposure assumed Both of the above are “expert judgment” evaluations that result in conclusion (ii)
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Stemware and Decanters Typical consumer seldom uses crystal (occasional or ceremonial use) - negligible exposure Establish worst case exposure scenario Compare to worst case to PTWI 25 g/kg bw/wk Calculate potential blood lead increase Slope factors IEUBK or PBPK modeling If less than 10% PTWI and less than 1 g/dL increase in blood lead then exposure is low
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Reasonable Worst Case Scenario Assume all beverages consumed using crystal products Pb in beverage values provided by ICF from recent lead elution studies Couple this to (ICF provided) data on beverage consumption in the EU Combine the two to generate an estimate of lead intake from crystal stemware and decanter use for short-term storage
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Sample calculations - Stemware First time use of crystal stemware can yield 100 – 200 g/L Pb. 200 ml serving size yields up to 40 g Pb intake Single serving would not elevate blood lead Chronic intake at this level could be of concern but Pb elution attenuates with stemware use (15 g/L) Chronic oral intake assumed to be associated with lower elution level Index to average per capita intake of spirits, wine, mineral water etc., 6 g/day ingestion
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RWC for Crystalware ProductRouteRWC PbB % PTWI StemwareOral 6 g/d 0.5 (PBPK) 0.3 (SF) 2.4% Decanter (short-term) Oral 2 g/d 0.17 (PBPK) 0.1 (SF) 0.8% Decanter (long-term)* Oral??? * Awaiting new ICF data. Literature values of > 1 mg/L could be a problem
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Stemware/Decanter Conclusions Exact numbers can be challenged, but estimates are far below “screening criteria” for products Conclusion (ii) proposed for stemware and short- term decanter use Long-term decanter use unresolved and awaiting industry data Likely to the the product application of greatest concern – and the most difficult to model High accumulation if not consumed, but if not consumed where is the exposure? Probabilistic modeling may be required
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Local Exposures Screened emissions for air lead levels or soil lead (current contribution) that would increase PbB by 1 g/dL or more Facilities that did not pass this “screen” subjected to more detailed evaluation All crystal facilities had low predicted additions to soil (<30 ppm) All less than 500 ng/m 3 air screening All are concluded to be conclusion (ii) or no risk
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Conclusions – Lead Crystal Production I Coverage“OK” (on-going) Representative natureYes Inhalation exposure adequate?Yes (borderline) Dermal exposure adequate?Yes (published data) Blood lead data adequate?Yes RPE analysis completed?Not conducted
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Lead crystal glass production blood leads bar: median, cross: arithmetic mean, box: inter-quartile-range, whiskers: 90th and 10th percentile
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Conclusions – Lead crystal glass production II Typical blood lead values are all well below 40 µg/dL, and only the 90th percentile for the workplace category raw material handling (B1) exceeds the threshold of 40 µg/dL. Conclusion for male workers only – no data to assess presence of women of reproductive capacity workplace category job description worst case [90 th perc.] typical [median] no. of data risk conclusion B1raw material handling 4626286 (iii) B2forming processes 35181,690 (ii) B3cutting processes 36211,006 (ii) B4polishing processes 3116176 (ii) B5others 28151,237 (ii)
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Conclusions for Crystal Most crystal products pose little exposure risk (conclusion ii) – but careful scrutiny expected from some MS Long-term storage in decanters an issue to be resolved Local source issues do not appear to a problem Occupational exposures for males is conclusion (ii) except for raw material handling Issue of 10 g/dL limit for women may change this picture Rejection of MOS ref = 1 would create problems
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