Introduction

This screening assessment was conducted pursuant to sections 68 and 74 of the Canadian Environmental Protection Act, 1999 (CEPA 1999) (Canada 1999).

A screening assessment was undertaken on perfluorooctanoic acid (PFOA) (Chemical Abstracts Service Registry Number 335-67-1) and its salts. In addition, precursors to PFOA were considered on the basis of their contribution to the total presence of PFOA and its salts. The ammonium salt, CAS RN 3825-26-1, and the precursors, CAS RN 53515-73-4, CAS RN 678-39-7, CAS RN 65530-61-2, and CAS RN 70969-47-0 were found to meet the ecological categorization criteria for persistence, bioaccumulation potential and inherent toxicity to non-human organisms. However, none of these substances were considered to be a high priority for assessment of potential risks to human health, based upon application of the simple exposure and hazard tools developed by Health Canada for categorization of substances on the Domestic Substances List.

Screening assessments focus on information critical to determining whether a substance meets the criteria as set out in section 64 of CEPA 1999. Screening assessments examine scientific information and develop conclusions by applying a weight of evidence approach and precaution

This screening assessment includes consideration of information on chemical properties, hazards, uses and exposure. Data relevant to the screening assessment of these substances were identified in original literature, review and assessment documents and stakeholder research reports and from recent literature searches, up to November 2009 for ecological sections of the document and February 2009 for human health sections of the document. During the peer review process, an additional literature search was carried out to update the coverage of the human health data to November 2009. In addition, an industry survey on perfluoroalkyls/fluoroalkyls was conducted for the years 2000 and 2004 through Canada Gazette Notices issued pursuant to section 71 of CEPA 1999 (Canada 1999; Canada 2000b, 2004). These surveys collected data on the Canadian manufacture, import, uses and releases of perfluoroalkyls/fluoroalkyls. Toxicological studies were also submitted by industry under section 70 of CEPA 1999.

The approach taken in the ecological screening assessment is to examine various supporting information and develop conclusions based on multiple lines of evidence, such as persistence, exposure, trends, inherent toxicity, bioaccumulation and widespread occurrence in the environment. Evaluation of risk to human health involves consideration of data relevant to estimation of exposure (non-occupational) of the general population as well as information on health hazards. Decisions for human health are based on the nature of the critical effect and/or margins between conservative effect levels and estimates of exposure, taking into account confidence in the completeness of the identified databases on both exposure and effects, within a screening context. The screening assessment does not present an exhaustive or critical review of all available data. Instead, it presents the critical studies and lines of evidence supporting the conclusions^[1].

This draft screening assessment was prepared by staff in the Existing Substances programs at Health Canada and Environment Canada. The draft ecological assessment has undergone external written peer review/consultation. The draft human health screening assessment was externally reviewed by staff of Toxicology Advice & Consulting Limited; Dr. Sean Hayes (Summit Toxicology); Dr. Greg Kedderis (private consultant); Dr. Kannan Krishan (University of Montreal); and Dr. Donna Vorhees (Science Collaborative) for adequacy of data coverage and defensibility of the conclusions. Statements in this document do not necessarily reflect the opinions of the reviewers. However, all reviewer comments were considered carefully and, where appropriate, addressed. The final content and outcome of the draft screening risk assessment remain the responsibility of Health Canada and Environment Canada.

The critical information and considerations upon which the draft assessment is based are summarized below.