Hair samples from ancient, Chilean mummies revealed they suffered from arsenic poisoning, according to research from scientists at the University of California in Los Angeles, Live Science reported Tuesday.

The mummies, dating back to 1,500 years ago, were found in the Tarapaca Valley in Chile's Atacama Desert. Scientists previously found traces of arsenic in the mummies' hair from both the highland and coastal areas of the region, which was home to the Incan and Chinchorro civilization.

But it was not known if the people swallowed the arsenic when alive around 1450 A.D., or if it seeped into the hair through the soil after burial.

The researchers found that the arsenic was ingested though contaminated water, Live Science reported. The arsenic water also could have poisoned plants that were later eaten.

"In Chile, you have these sediments that are rich in arsenic because of copper-mining activities in the highlands," thus releasing the arsenic, Ioanna Kakoulli, a UCLA archaeological scientist who led the study, said according to Live Science.

"When it rains, the arsenic can leach out into the rivers," Kakoulli said.

The findings were published in the journal Analytical Chemistry.

Hair, which is comprised of the protein keratin, does not break down or change the way other biological materials do after death. This allows scientists to more accurately study what was eaten and the type of environment a person lived in.

Kakoulli and her team of scientists tested how the arsenic was distributed in the hair to determine where it came from. Tests involved using a high-resolution scanning electron microscope, along with a particle accelerator that uses X-rays to examine materials, Live Science reported.

The results showed that the arsenic was distributed throughout the hair, and not just on the surface which would have been indicative of it coming from the soil, Kakoulli told Live Science.

"The results are consistent with modern epidemiological studies of arsenic poisoning by ingestion," Kakoulli said.