Investigating museums' ‘dirty little secret’

A man in a blue lab coat lectures students in a classroom

Professor of Analytical-Environmental Chemistry Peter Palmer

Some items in collections have a toxic history that only chemistry can reveal

This story originally appeared on the University’s Bold Thinkers blog, which ran from May 2018 to Nov. 2019.

On a chilly fall evening in 2001, Professor of Analytical-Environmental Chemistry Peter Palmer was shivering in the hills west of Shasta, California, watching intently as members of the Hoopa Valley Tribe performed their celebratory White Deer Skin Dance. “The Hoopa have these deerskin pelts with eyes looking at you. The pelts are mounted on sticks — it’s really haunting,” Palmer says. “It’s amazing to see how these artifacts are meant to be worn.”

It’s a little outside his training as a chemist who tests environmental pollution, but artifacts like these have become an important focus of Palmer’s work.

Museum conservators, concerned about insects and rodents, used to treat items in their collections with pesticides like arsenic and DDT. (At the time, it wasn’t known that these substances act as neurotoxins to humans.) Since 1990, when the Native American Graves Protection and Repatriation Act created a legal pathway for Native American tribes to request that artifacts be returned to them, the tribes have had to grapple with this toxic history. As museums rarely maintain records of the use of pesticides, it’s often unknown whether important pieces of heritage were tainted during their time sitting in collections.

“The problem is still out there,” said Palmer. “It’s the museums’ dirty little secret.”

In 1999, San Francisco State Archaeologist Jeffrey Fentress approached Palmer with the idea of testing several items in the University’s collection for the presence of pesticides. The chemist’s first instinct was to say no. “I didn’t know anything about this problem,” Palmer explained. “But then I figured, ‘We’ve got the equipment. And there’s no standard method, but I think we can develop one.’” So he worked with SF State student Matt Martin for months to find a way to accurately measure levels of pesticides in the objects.

Over the following two decades, Palmer has worked with Native American tribes 10 times to test such objects after they were returned to their rightful owners from museum collections.

The work holds some unique difficulties. The sacred nature of some artifacts means researchers often can’t use standard “destructive techniques,” which involve grinding up a small piece of the item to be tested. Complicating things further, the paints and natural products used to make artifacts can contain trace amounts of heavy metals, too — and figuring out whether the toxins have a natural origin adds more steps to the testing process.

At times, the results of the testing have been shocking. “It stunned people to learn the levels of toxins on these artifacts,” Palmer said. The traditional garb returned to the Hoopa tribe, for instance, was so contaminated with mercury that they couldn’t be safely worn. Since there’s no way to remove the toxins, the outfits are now displayed behind glass rather than worn as intended.

Only a handful of analytical chemists around the country even take on projects like these, in part because of the challenge of getting funding for the work. Despite the regulations requiring that artifacts be returned to tribes, there are no requirements that they be tested. Palmer ended up self-funding several of his testing projects, scraping together supplies and the means to train about a dozen student volunteers to perform analyses.

But the work has its rewards, too, such as being invited to ceremonies like the Hoopa’s White Deer Skin Dance. Last year, Palmer performed testing on baskets from SF State’s own collections in the Department of Anthropology for the Elem Pomo tribe. He and his students were able to confirm the artifacts were free of toxins — and representatives of the tribe invited him to watch the baskets be returned to their home. “These are from the high craftsmen of their art and they’ve been gone for so many years. This ceremony was to welcome them back,” Palmer explained. “I got paid in full that day. You can’t put a price on these things.”