Federal guidance released for human health risk assessments
Health Canada (HC) has released two supplemental guidance documents that provide guidance and information on key issues and methods that are acceptable when conducting human health risk assessments (HHRAs) that evaluate potential exposure to sediment or air at contaminated sites under federal jurisdiction in Canada.
The two documents may also be useful references in HHRAs for other, non-federally regulated contaminated sites, where no jurisdiction-specific guidance is available.
Released on June 29, 2017, they are:
- Federal Contaminated Site Risk Assessment in Canada, Supplemental Guidance on Human Health Risk Assessment of Contaminated Sediments: Direct Contact Pathway
- Federal Contaminated Site Risk Assessment in Canada: Supplemental Guidance on Human Health Risk Assessment of Air Quality, Version 2.0
Both publications are available to order at no cost through the Health Canada website.
The risk assessment approach presented in these documents is based primarily on the standard Preliminary Quantitative Risk Assessment (PQRA) and Detailed Quantitative Risk Assessment (DQRA) approach described by Health Canada for contaminated sites, but have been modified specifically for the assessment of chemicals in sediment and air, respectively.
Currently, there are no human health-based sediment criteria or guidelines established by a Canadian jurisdiction. The purpose of the supplemental guidance document for Sediment: Direct Contact is to provide information related to evaluating human exposure to chemicals in sediments via direct contact (i.e., incidental ingestion, dermal contact and inhalation of particulates), especially where receptor characteristics and exposure scenarios for aquatic sediment sites may differ from terrestrial (soil) sites. Two criteria are used to distinguish between human exposure to sediment and human exposure to soil. The first criterion is that sediment is, at least periodically or seasonally, underwater or saturated with water and/or may be routinely suspended in water, while soil remains consistently drier. The second criterion is that human activity and/or exposure that occurs at an aquatic environment is expected to differ substantially from that in a terrestrial environment. The document provides recommendations for sourcing human health specific screening criteria for chemical concentrations in sediment and provides guidance for evaluating human health exposure for three generic sediment exposure scenarios: 1) Recreational Low-Contact (General Public - All Ages); 2) Recreational High Contact (General Public - All Ages); and 3) Commercial/Industrial (Adult workers).
The revised Air Quality publication removed its table of air quality screening criteria that had been included in the previous version of this guidance. Instead, the new guidance references Health Canada Residential Indoor Air Quality Guidelines (exposure limits) for a limited list of contaminants and provides a recommended hierarchy for obtaining screening criteria from other jurisdictions when values are not available from Health Canada.
How can GHD help?
GHD's strong technical team has extensive experience with environmental investigation, risk assessment, risk management and remediation, in accordance with guidance from Health Canada, United States Environmental Protection Agency and many other jurisdictions across North America and throughout the world. Our team's experience and up-to-date knowledge of a wide variety of risk-based regulatory programs enables us to use risk assessment to manage contaminated sites and optimize environmental cleanups. Please contact a GHD Environmental Risk Assessor for more information on how these and other risk assessment guidance documents can integrate into your environmental investigations to help determine the most appropriate path forward at your site.
For more information, please contact:
Christine Plourde | FEC, P.Eng., Human Health Risk Assessor
466 Hodgson Road, Fredericton, NB E3A4Z9
E: christine.plourde@ghd.com | T: +1 506 458 1248
Steven Harris | Principal, Environmental Risk Assessment Services
651 Colby Drive, Waterloo, ON N2V 1C2
E: steve.harris@ghd.com | T: +1 519 884 0510 ext.3513