CHEMICAL PROFILES|Scorecard's Risk Assessment Values



WHAT ARE RISK ASSESSMENT VALUES?
Risk assessment values (RAVs) are numbers that help define the level of health risk posed by a toxic chemical. RAVs are derived from dose-response data obtained from human or animal studies to provide a summary measure of the toxicity of a chemical. Regulatory agencies calculate separate numbers for carcinogens (potencies) and non-carcinogens (reference doses or concentrations). Cancer potencies express how much added cancer risk is associated with lifetime exposure to a unit dose of a chemical (presented as the additional cancer risk associated with an average daily dose of one milligram of a chemical per kilogram of bodyweight). Reference doses and concentrations are estimates of the daily exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects over a lifetime.

Risk assessment values or media quality standards can be used to evaluate the health risks posed by exposures to toxic chemicals. Media quality standards can be compared directly to information about the concentration of a chemical in the environment to identify potential health hazards. If a chemical concentration exceeds a relevant media quality standard, action to reduce environmental contamination or exposure is warranted. Unfortunately, there are relatively few chemicals with standards that define allowable concentrations in air, water, or food. More chemicals have risk assessment values , which can be combined with information about the dose of a chemical that someone receives to characterize health risks. See Scorecard's Guide to Health Risk Assessment for instructions about how to use RAVs to estimate health risks if you have information about chemical exposures.

WHERE DO SCORECARD'S RISK ASSESSMENT VALUES COME FROM?
Scorecard includes all risk assessment values that have been developed by the state of California or by national regulatory agencies, such as the U.S. Environmental Protection Agency or the Agency of Toxic Substances and Disease Registry. A prioritization scheme determines which agency's RAV will be used if multiple agencies have developed RAVs for the same chemical. To ensure that RAVs are derived as consistently as possible, Scorecard adopts the agency with largest number of RAVs available as its priority source. California regulatory agencies have derived more cancer potency values and inhalation reference concentrations for chemical than any federal agency, so Scorecard preferentially adopts these RAVs. EPA has derived more oral reference doses than any agency, so Scorecard preferentially adopts these RAVs. Other sources are then used if needed, ordered by the extent to which RAVs have undergone either scientific or regulatory review.

More on the availability of RAVs.

IMPORTANT NOTE
Scorecard's RAVs have been derived to protect against chronic health effects only and are not appropriate for assessing acute (short-term) exposures.

HOW CAN I GET A COMPLETE LIST OF SCORECARD RISK ASSESSMENT VALUES?
Scorecard risk assessment values are available as a CSV file, which contains chemical name, CAS number, Scorecard's preferred RAV values (for inhalation and ingestion cancer potency, reference doses and reference concentrations), and an abbreviated reference citation for each RAV. Full citations for these abbreviations are provided on Scorecard's RAV reference page.

CSV files can be easily opened by most word processing, spreadsheet or database applications (just be sure to let your application know you're opening a text file that is in comma-separated value format).