Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 302 - WATER QUALITY STANDARDS
Subpart F - PROCEDURES FOR DETERMINING WATER QUALITY CRITERIA
Section 302.651 - The Human Nonthreshold Criterion

Universal Citation: 35 IL Admin Code ยง 302.651

Current through Register Vol. 48, No. 38, September 20, 2024

The Human Nonthreshold Criterion (HNC) of a substance is the concentration or level of a substance at which humans are protected from an unreasonable risk of disease caused by a nonthreshold toxic mechanism as a result of incidental exposure to or ingestion of surface waters of the State or ingestion of aquatic organisms taken from surface waters of the State. HNCs are derived for those toxic substances for which any exposure, regardless of extent, carries some risk of damage as specified in subsections (a) and (b).

a) For single substances, a risk level of one in one million (1 in 1,000,000) must be allowed (i.e., considered acceptable) to determine an HNC.

b) For mixtures of substances, an additive risk level of one in one hundred thousand (1 in 100,000) must be allowed (i.e., considered acceptable) to determine an HNC.

Disclaimer: These regulations may not be the most recent version. Illinois may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.