Current through Register Vol. 48, No. 51, June 17, 2024
Part 4717.8550 - PROCEDURE FOR DETERMINING CANCER INDEX FOR SIMULTANEOUS EXPOSURE TO MULTIPLE CARCINOGENSSubpart 1.Cancer index.To evaluate simultaneous exposure for multiple carcinogens, a cancer index must be calculated using the procedure in this part.
Subp. 2.Carcinogenic HRVs.For health risk values (HRVs) that have cancer endpoints, items A to C apply.
A. A cancer index is determined for chemicals or defined mixtures of chemicals with an inhalation endpoint of cancer using the following equation: | Cancer index = | EC1 _____ HRVC1 | + | EC2 _____ HRVC2 | + + | ECn _____ HRVCn | |
Where:
(1) ECn represents the measured or modeled ambient air concentration as expressed in units of micrograms per cubic meter ( µg/m3) of the first, second, through the nth carcinogen; and(2) HRVCn represents the chronic HRV of the first, second, through nth carcinogen as expressed in units of micrograms per cubic meter ( µg/m3).B. A cancer index of one is equivalent to a cumulative HRV. A cancer index greater than one exceeds the cumulative HRV.Subp. 3.Carcinogenic MHRVs.For mixtures of multimedia health risk values (MHRVs) that have cancer endpoints, items A to C apply.
A. A cancer index is determined for chemicals or defined mixtures of chemicals with an endpoint of cancer using the following equation: | Cancer index = | DC1 _____ MHRVC1 | + | DC2 _____ MHRVC2 | + + | DCn _____ MHRVCn | |
Where:
(1) DCn represents the calculated lifetime averaged daily dose of the first, second, through the nth carcinogen as expressed in units of micrograms per kilogram of body weight per day ( µg/kg-d); and(2) MHRVCn represents the MHRV of the first, second, through the nth carcinogen as expressed in units of micrograms per kilogram of body weight per day ( µg/kg-d).B. A cancer index of one is equivalent to a cumulative MHRV. A cancer index greater than one exceeds the cumulative MHRV.Statutory Authority: MS s 144.12