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Need for and p revalence of separate g uidelines

Acute Toxicity SCTL Issues. Need for and p revalence of separate g uidelines List of substances: Ba, Cu, CN - , F - , Ni, Phenol, V ( cadmium evaluated, default SCTL protective of acute tox too ) Ingestion rate: 10 grams one event ( 50x default ) Review of t ox values to be used

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Need for and p revalence of separate g uidelines

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  1. Acute Toxicity SCTL Issues • Need for and prevalence of separate guidelines • List of substances: Ba, Cu, CN-, F-, Ni, Phenol, V (cadmium evaluated, default SCTL protective of acute tox too) • Ingestion rate: 10 grams one event (50x default) • Review of tox values to be used • Bioavailability: Assumed 100% Draft Copy Subject To Change

  2. Need / Prevalence • Pica behavior recognized, but acute exposure harm? • FL sites can be driven by acute tox values (e.g., Ba) • Other states/federal/international guidance • CA (HHSLs don’t include acute exposure) • MA (CN- only) • MN (Ba, Cu, CN-, F-, Phenol) • NY (As, Ba, Cd, Cu, CN-, Ni, Naph, Penta, Phenol); cites FL as basis • USEPA (RSLs do not address acute exposure) • Canada (CN- only) • Regulation of other media (GW, SW) does not single out extreme outlier population Draft Copy Subject To Change

  3. List of Chemicals • CN- and phenol have reasonable basis in tox • Tox of Ba, Cu, F-, Ni, V lacks good foundation • Endpoints for some are ambiguous, transient, reversible; should have real hazard potential • Same substances present in dietary, commercial products at higher levels Draft Copy Subject To Change

  4. IngestionRate • 10 gram, single event existing assumption • Historical support as infrequent acute exposure • More indicative of extreme pica or geophagy • Frequency of events (e.g., 33% may ingest 10g 1-2 times per year), often cited but weakly supported • Calabrese et al. (1997) cites 200 mg/day protects 95% of children • 1 to 5 gram range for pica recommendation (2011 EFH, 2008 Child EFH, CalEPA 2012, literature) Draft Copy Subject To Change

  5. Toxicological Guidance • RfDacute values developed from human studies • RfDacute for some substances set very close to acceptable dietary recommendations • Large soil bolus alone may cause adverse effects • Existing dose/response from nonsoilexposures • Majority of effects gastrointestinal, transient Draft Copy Subject To Change

  6. Bioavailability • Chemical-specific, but defaults to 100% • Limited or no literature for most chemicals • Other default recommendations (e.g., 50% MADEP) • Single acute exposures beg question: Are there no reports of effect because toxins unavailable Draft Copy Subject To Change

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