Residues of DDT, a pesticide banned decades ago, have been found in brook trout in New Brunswick lakes at levels far above safety limits, raising new concerns about long-term contamination of food chains.
Sinéad Campbell reports for The Guardian.
In short:
- Researchers found DDT levels in brook trout muscle tissue that were up to 10 times the Canadian safety limit for wildlife, even though the pesticide was last used in the region more than 50 years ago.
- About half of New Brunswick’s lakes are contaminated with legacy DDT, much of it still stored in lake sediment, which acts as a long-term source of pollution in aquatic food webs.
- DDT was widely sprayed in the province's forests during the 1950s and 60s before being banned in the 1980s; the contamination persists despite the global ban for agriculture under the Stockholm Convention in 2001.
Why this matters:
Persistent organic pollutants like DDT resist breakdown and continue to circulate through ecosystems long after their use has ended. Even as DDT was banned in Canada decades ago and globally restricted since 2001, it remains embedded in sediments and continues to enter the food chain, threatening fish, birds, mammals, and people who eat contaminated wildlife. Brook trout, a popular sport and subsistence fish, are widely consumed in New Brunswick. When these fish carry DDT levels far beyond safety limits, they expose communities to chemicals linked to cancer and reproductive harm. This legacy contamination also raises broader concerns about how we use and regulate synthetic chemicals. Many pesticides applied today could follow the same path, silently accumulating in soils, waters, and bodies over generations. It's a sobering warning about the long tail of chemical pollution.
Related EHN coverage: Long-banned toxics are still accumulating in Great Lakes birds—as new chemical threats emerge
