An anonymous reader quotes a report from the Guardian: Even low levels of common agricultural pesticides can stunt the long-term lifespan of fish, according to research led by Jason Rohr, a biologist at the University of Notre Dame in Indiana. Signs of aging accelerated when fish were exposed to the chemicals, according to the study, published in Science, which could have implications for other organisms. […] The research found that fish from pesticide-affected lakes showed shortened telomeres, the caps at the end of chromosomes that are known as the biological clock for aging. When they shorten, it is a sign of cellular aging and a decline in the body’s regenerative capacity. The lake populations consisted of younger fish, indicating that the pesticides contributed to shortened lives. Laboratory experiments confirmed the findings and showed chronic low-dose exposure reduced fish survival and degraded telomeres. These effects were not seen with acute high-dose exposure.
Chemical analysis showed chlorpyrifos, which is banned in the UK and the EU but used in the US and China, was the only compound found in the fish tissues that was consistently associated with signs of aging. These included shortened telomeres and lipofuscin deposition — a buildup of insoluble proteins often described as cellular “junk”. The worrying aging effects occurred at concentrations below current US freshwater safety standards, Rohr said, suggesting the effects of chemicals and pesticides could be occurring at low levels over the long term. While short-term exposure to high doses did not appear to cause these aging issues — though it did cause high toxicity and death in fish — the researchers concluded that it was long-term exposure to low doses that drove the changes. The scientists added that reduced lifespan was particularly problematic because older fish often contribute disproportionately to reproduction, genetic diversity and population stability.