Tests fail to pinpoint cause of two summer fish kills in PEI
Tests by Environment Canada at its laboratory in Moncton, New Brunswick have failed to determine the exact cause of two separate incidents of fish kills that occurred in July at Dunk River and Tryon River, Prince Edward Island, in July. The lack of evidence that would establish the cause or origin of the pollution incidents means that no charges can be laid under the pollution prevention provisions of the federal Fisheries Act at this time, said the department. The incidents were investigated jointly by Environment Canada and PEI's Department of Environment, Energy and Forestry.
Samples of water, vegetation, sediment and fish from both locations were analyzed at the federal laboratory. Samples from the Tryon River were found to contain Chlorothalonil, a pesticide, while Metribuzin, another pesticide, was detected in samples from the Dunk River.
Pesticide levels in the water samples from both rivers were well above those for Chlorothalonil and Metribuzin set out in guidelines for the protection of freshwater aquatic life established by the Canadian Council of Ministers of Environment (CCME), but were not high enough to kill fish. Officials believe Chlorothalonil was present in the Tryon River at higher levels immediately a rainfall that occurred three days before the samples were collected. Metribuzin is less toxic than Chlorothalonil and is not considered the cause of the fish kill in the Dunk River.
The low levels of pesticide found in the fish tissue samples is not surprising in view of the length of time between the fish kill occurrences and the gathering of samples: two days elapsed between the Tryon River fish kill and its reporting, three days between the Dunk River incident and its reporting. Although government officials gathered samples immediately after each kill was reported, the fish had already been dead for at least two days, which would have caused the amount of pesticide present in their bodies to degrade before the samples were tested.
Low or trace levels of other pesticides were also found, including Linuron (in very small amounts in Dunk River and Tryon River water samples as well as fish tissue samples) and Carbofuran, Metalaxyl and B-Endosulfan (trace levels in some water and sediment samples). None of the levels found would be toxic to aquatic life.
The two fish kill incidents affected thousands of fish, including many large salmon and rainbow and speckled trout. Although only a section of the Dunk River was affected, the entire river, along with the east branch of the Tryon River have been closed to angling for the remainder of the year.
Environment Canada environmental enforcement field officers will continue to inspect properties adjacent to water bodies on Prince Edward Island. Officials emphasize that more sustainable land management practices will also offer greater protection for these rivers and other bodies of water in the future.