Hair lead levels differed among the three groups of macaques, and were much higher in younger macaques. The researchers' data did not support the idea that these lead levels were from basic differences in the animals' diet, and instead suggested that, in this population of macaques, behavioral or physiological factors among young macaques might play a significant role in determining exposure to lead and subsequent tissue concentration.

Animal sentinels of poisonous conditions for people have been used for a long time. From the 19th century and well into the 20th century coal miners sent canaries into mining shafts to check if the air was safe to breathe.

"While using animal sentinels is not a new phenomenon, we argue that not all animal species are relevant models for human toxicant exposures, but young macaques that share the same ecological niche with humans may be one of the best animal sentinels we have," Engel said.

Scientists testing for environmental exposures also don't want to hurt the animals they are monitoring. Collecting a few hairs is a gentle, non-invasive approach.

The researchers noted, "All of these factors contribute to making synanthropic macaques -- those that share the environment with humans -- potentially valuable as sentinels for toxic exposures and predictors of physiologic responses in humans."

The research team concluded, "Chemical analysis of hair is a promising, non-invasive technique for determining exposure to toxic elements in free-ranging, non-human primates, and further multidisciplinary research is needed to establish whether it can be used to predict lead levels in humans who live in the same areas."

Source: University of Washington