She and her team of primatologists, physicians, epidemiologists, veterinarians and toxicologists decided to test urban macaques as a potential early indicator that their human neighbors, especially the children, are being exposed to lead and other toxic metals. They took hair samples from three groups of free-ranging macaques at the Swoyambhu temple overlooking Kathmandu, Nepal. The macaques patrolling the site have abundant contact with people and with human-made environments. This World Heritage Site temple is located in a densely populated urban area with poor infrastructure that leaves point sources like discarded lead batteries, flaking leaded paint, and lead contaminated soil, a by-product of decades of leaded fuel, in the environment.
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
|Contact: Leila Gray|
University of Washington