In 2006, the Government of Canada initiated the Chemicals Management Plan (CMP), which takes action regarding chemicals that are harmful to human health or the environment. One element of the CMP is Monitoring and Surveillance, which generates data on the presence and levels of chemical substances in environmental matrices. These data are used to make decisions regarding the best approach to protect Canadians and their environment from risks these substances might pose. In support of the CMP, a wastewater monitoring program was initiated in 2009 to generate data on priority substances that may be released to the environment. The wastewater sector has been identified as an important release point to the environment for certain CMP substances. The purpose of the wastewater monitoring program is to gather information from representative municipal wastewater treatment plants (WWTPs) across Canada to determine the levels of selected chemical substances entering WWTPs, the fate of these substances through typical wastewater and sludge treatment processes (primary treatment, activated sludge treatment, lagoon treatment, etc.) at warm and cold process temperatures, and the levels of these substances being discharged in WWTP effluents and solids residuals. The participation of various WWTPs in this program is done on a voluntary and anonymous basis, and sampling commences once a Collaboration Arrangement has been signed by the Municipality and Environment and Climate Change Canada. The results from this monitoring project are used to improve our understanding of the fate of chemical substances during wastewater treatment and to determine if control measures are needed to prevent these substances from entering municipal wastewater systems.

Categorization was required by the Canadian Environmental Protection Act, 1999 (CEPA 1999) and is a first step to finding out which of these chemical substances require further attention in the form of assessment, research and/or measures to control their use or release. This task was completed by September 2006, as required by the act. Using information from Canadian industry, academic research and other countries, Government of Canada scientists worked with partners in applying a set of rigorous tools to the 23,000 chemical substances on the Domestic Substances List (DSL). They were categorized to identify those that were: • Inherently toxic to humans or to the environment and that might be: o Persistent (take a very long time to break down), and/or o Bioaccumulative (collect in living organisms and end up in the food chain) • Substances to which people might have greatest potential for exposure. Through categorization, the Government of Canada identified approximately 4,000 of the 23,000 chemical substances on the DSL as meeting the criteria for further attention.