Low pesticide exposure speeds aging in fish ^{CEFR B1}

A team led by a University of Notre Dame biologist reported that long-term exposure to low levels of a common agricultural insecticide can accelerate physiological aging and shorten lifespan in fish. The work began with field studies in China that examined thousands of fish collected over several years. Researchers found that populations in contaminated lakes lacked older individuals, while lakes with little contamination included many older fish. They interpreted this pattern as earlier death rather than lower reproduction.

Chemical analyses of fish tissues showed that chlorpyrifos was the only compound consistently linked to biological signs of aging. The team measured shortened telomeres, which protect chromosomes, and increased deposition of lipofuscin, a build-up of old proteins and metals in long-lived cells. Controlled laboratory experiments using chlorpyrifos concentrations similar to those found in the wild caused progressive telomere shortening, greater cellular aging and reduced survival. Effects were strongest in fish from contaminated lakes, which were already physiologically older.

Short-term exposure to much higher doses led to rapid toxicity and death but did not cause telomere shortening or increased lipofuscin. The loss of older individuals can harm ecosystems because older fish often contribute disproportionately to reproduction, genetic diversity and population stability. The authors note that telomere biology and aging mechanisms are highly conserved across vertebrates, including humans, which raises wider concerns.