High levels of DDT found in N.B. brook trout decades after spraying
A recent study conducted by researchers at Mount Allison University has revealed that DDT, a pesticide sprayed on New Brunswick forests more than 55 years ago, can still be found in some brook trout in the province. The synthetic insecticide was sprayed from planes across northern and central New Brunswick between 1952 and 1968 to control the spruce budworm population. However, the residue left behind by DDT has persisted in the environment, raising concerns about its impact on wildlife.
Joshua Kurek, an associate professor of environmental science at Mount Allison University and the principal investigator of the study, emphasized the importance of raising awareness about the presence of DDT in today’s environment. The research team sampled brook trout from seven lakes across the province, with results showing high concentrations of DDT in trout populations from areas where the pesticide was sprayed.
DDT, a known carcinogen, was found in concentrations 10 times greater than the levels considered healthy for wildlife that consume the fish. This poses a significant risk to various organisms in the food chain, including loons, minks, otters, and even humans who consume brook trout. The presence of DDT in the lake sediments allows small aquatic insects to feed on it, which are then consumed by brook trout, leading to bioaccumulation of the pesticide in their tissues.
The study also revealed that DDT can travel atmospherically and be carried from land to nearby water bodies by heavy rain or surface water. As a result, low levels of DDT were detected in trout from lakes outside the spray zones, indicating the widespread impact of the pesticide on the environment. Kurek emphasized the need for further research to understand how DDT enters lakes from forest soil and its effects on fish populations.
In response to the findings, the Department of Health in New Brunswick stated that the DDT levels found in brook trout exceed wildlife consumption guidelines but do not pose a significant risk to human health. However, the department advised residents to follow fish consumption limits, especially for vulnerable populations such as pregnant women, infants, and children.
The study, published in the peer-reviewed journal PLOS One, highlights the long-lasting effects of pesticides on the environment and the importance of monitoring and regulating their use to protect wildlife and human health. As New Brunswick continues to grapple with the legacy of DDT contamination, efforts to mitigate its impact on ecosystems and ensure the sustainability of fish populations remain crucial.
