VI. TOXICITY REFERENCE VALUES
A. Oral/Ingestion
U.S. EPA Reference Dose (RfD) for Chronic Oral Exposure: 2E-1 (or 0.2) mg/kg-day, based on reduced weight gain and histopathology of the gastrointestinal tract in adult rats (www.epa.gov/iris/subst/0419.htm, I.A.1) (11); last Workgroup Verification Date 6/20/90.
U.S. EPA Drinking Water Advisories (10 kg child): 1 day = 10 mg/L, 10 day = 5 mg/L (http://www.epa.gov/waterscience/criteria/drinking/standards/dwstandards.pdf) (52); last revised Winter, 2006.
U.S. ATSDR Minimal Risk Level (MRL) Oral: 0.3 mg/kg/day (intermediate oral), based on gastrointestinal effects; 0.2 mg/kg/day (chronic oral), based on gastrointestinal effects (http://www.atsdr.cdc.gov/mrls/index.html) (53); last revised 7/99.