On 2020 November 23, the independent laboratory that analyzes water discharge samples from the Port Granby Waste Water Treatment Plant notified CNL of an exceedance of an allowable level set to prevent harm to fish. All other discharge parameters were within allowable limits. On receipt of this information, CNL immediately stopped discharging treated water to Lake Ontario.
Further samples have been sent to the laboratory for analysis, and CNL will not resume discharging water to the lake until results confirm that the treated water is within all allowable limits.
This event does not pose a risk to human health or the safety of people, and the initial analysis results indicate the impact on the environment to be negligible. CNL routinely tests the treated discharge water from the Port Granby Waste Water Treatment Plant, and years of sampling data shows that the treated water has been within allowable limits prior to this result.
Ongoing testing continues to show that the plant’s advanced treatment technology meets or exceeds stringent Canadian Nuclear Safety Commission requirements for water discharged to Lake Ontario, resulting in enhanced protection of the Great Lakes Basin ecosystem.
CNL notified the Canadian Nuclear Safety Commission and the Municipality of Clarington.