| Summary: | The Crown Contaminated Sites Branch (CCSB) of the Ministry of Agriculture and Lands (MAL) manages contaminated sites on Crown land where responsibility has defaulted to the Province. CCSB uses a multi-step prioritization process to identify and screen candidate contaminated sites, one of which is the Risk Ranking Methodology (RRM). Initially developed for MAL’s mines portfolio, the goal of the RRM is to provide a scientifically based method for evaluation and ranking of candidate Crown contaminated sites for potential risks to human health and the environment. MAL’s RRM has two components: (1) a risk ranking support tool (spreadsheet and documentation, known as the “Tool”) and (2) a workshop process. The Tool considers human health and ecological aspects separately. It calculates “weighted” chemical concentrations for various media, and then a screening quotient is determined using specified screening values. In addition, a series of important “flags” specific to the values being protected (e.g., humans, fish, listed species) are used to characterize the site. The RRM generates a comparative summary of the various lines of evidence for each site which is then used to support an expert process workshop to direct management decisions for undertaking additional site investigations and remediation.
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