Reference dose classification

PEL Pg pmol PHS PMR ppb ppm ppt REL RfD RTECS sec SCE SIC SIR SMR STEL STORET TLV TSCA TRI TRS TWA u.s. UF yr WHO wk permissible exposure limit picogram picomole Public Health Service proportionate mortality ratio parts per billion parts per million parts per trillion recommended exposure limit Reference Dose Registry of Toxic Effects of Chemical Substances second sister chromatid exchange Standard Industrial Classification Standardized incidence ratio standard mortality ratio short term exposure limit STORAGE and RETRIEVAL threshold limit value Toxic Substances Control Act Toxics Release Inventory total reduced sulfur time-weighted average United States uncertainty factor year World Health Organization week... 

IRIS is a toxicology data file that contains data in support of human health risk assessment. It is compiled by the US EPA and contains over 500 chemical records. IRIS data, focusing on hazard identification and dose-response assessment, are reviewed by work groups of EPA scientists and represents EPA consensus. Among the key data provided in IRIS are EPA carcinogen classifications, unit risks, slope factors, oral reference doses, and inhalation reference concentrations. 

For non-carcinogens, MCLGs are determined by a three-step process. The first step is calculating the reference dose (RfD) for each specific confaminanf. The RfD is an estimate of the amount of a chemical that a person can be exposed to on a daily basis that is not anticipated to cause adverse systemic health effects over the person s lifetime. A different assessment system is used for chemicals that are potential carcinogens. If toxicological evidence leads to the classification of the contaminant as a human or probable human carcinogen, the MCLG is set at zero (Boyce, 1997). 

Classification of the anabolic steroids is based on chemical stmctures and associated actions. A review of the biosynthesis and metabolism of the naturally occurring estrogens and androgens is available (1). Names, descriptions, approval dates, and recommended doses of the commercial products are found in References 1, 8, and 9. Although steroids may be orally active, the FDA approved mode of adrninistration is the subcutaneous implant. Effective dose is lower with implant rather than oral adrninistration. 

When a chemical is characterized only by use of animal data (typical of new chemicals, but also true for many existing chemicals), the classification process would include reference to dose/concentration guidance values as one of the elements that contribute to the weight of evidence approach. 

Authors) Year No of patients Inclusion diagnoses [Classification] Test p repara tion/daily dose Reference snbstance/daily dose Duration of treatment Analysis/ Results (bold print primary ontcome variable if specified)... 

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