We have developed guidance to help people understand how to make cleanup level adjustments to comply with target risk-based goals required by the MTCA cleanup regulation (Chapter 173-340 Washington Administrative Code). We invite you to review and comment on the following document:
· Draft MTCA Guidance: Method B and C Target Cleanup Goals and Adjustments for Additive Risk and Hazard
Cleanup levels established under MTCA Methods B and C may need to be adjusted downward to account for exposure to multiple hazardous substances and/or exposure pathways. This adjustment needs to be made only if, without this adjustment, the noncancer hazard index (HI) would exceed 1, or the total excess cancer risk would exceed an excess risk of one in one hundred thousand (1 x 10-5).
This guidance provides instruction (with practical examples) on adjusting cleanup levels to meet MTCA’s additive risk-based goals for cancer (1 x 10-5) and noncancer (HI of 1) health endpoints under Methods B and C. Topics discussed in the guidance include considerations for applicable state and federal laws (i.e., ARARs), accounting for multiple pathways of exposure, significant figures when interpreting risk results, methods for calculating cancer risk and noncancer hazard, and how to make adjustments.
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We have developed guidance to help people understand how to make cleanup level adjustments to comply with target risk-based goals required by the MTCA cleanup regulation (Chapter 173-340 Washington Administrative Code). We invite you to review and comment on the following document:
· Draft MTCA Guidance: Method B and C Target Cleanup Goals and Adjustments for Additive Risk and Hazard
Cleanup levels established under MTCA Methods B and C may need to be adjusted downward to account for exposure to multiple hazardous substances and/or exposure pathways. This adjustment needs to be made only if, without this adjustment, the noncancer hazard index (HI) would exceed 1, or the total excess cancer risk would exceed an excess risk of one in one hundred thousand (1 x 10-5).
This guidance provides instruction (with practical examples) on adjusting cleanup levels to meet MTCA’s additive risk-based goals for cancer (1 x 10-5) and noncancer (HI of 1) health endpoints under Methods B and C. Topics discussed in the guidance include considerations for applicable state and federal laws (i.e., ARARs), accounting for multiple pathways of exposure, significant figures when interpreting risk results, methods for calculating cancer risk and noncancer hazard, and how to make adjustments.
Contact Information
*Indicates Required Fields