When scientist Jay Rotella stepped out of the cargo plane’s dark cavern onto Antarctica for the first time, all he saw for miles was white snow and black rock. “It’s hard to believe there is an entire pristine continent set aside – and you are standing on it,” said Rotella, who studies Weddell seals.

Yet Antarctica is not untouched. Penguins, fish, sea sponges and even worms there are contaminated with flame retardants. In some sediment at McMurdo Sound, one widely used chemical was found at levels similar to those found in urban rivers. Research stations are the apparent source.

“Antarctica is a place that the international community works hard to preserve. Ironically, the research stations that are set up to help are themselves pollution sources,” said Da Chen, an ecotoxicologist at Southern Illinois University.

More than 30 countries maintain more than 70 bases on the continent, mostly for scientific research. Upwards of 4,000 scientists and others make their home in Antarctica during the summer research season, plus about 34,000 tourists.

Rising like a college campus on a gravel hill stands McMurdo Station, the U.S. research base, complete with dormitories, a fuel depot and as many as 1,200 people during peak research months.

The new study measured hexabromocyclododecane, or HBCD, inside McMurdo Station and a nearby New Zealand base, and in wildlife and sediment at McMurdo Sound, where wastewater from the bases enters the ocean. The findings by Chen and his colleagues, which have not yet been published, were presented at a toxicology conference last fall.

HBCD has been widely used worldwide for several decades in insulation and building materials to try to stop fires from spreading. The chemical accumulates in the tissues of animals and people, and like other flame retardants with similar properties, researchers suspect it alters hormones.

The HBCD levels in McMurdo Sound sediments nearest the wastewater outflow were comparable to those found in some highly urbanized rivers in Europe and the United States, such as the Detroit River, Chen said.

Animals, particularly sea sponges, living closest to outflow pipes had the highest levels.

Antarctic animals have not been studied for any possible effects. But in fish and rodents studied in laboratories, the chemical can disrupt thyroid hormones, which guide brain development and metabolism. It has been linked to effects on animal brains, glucose levels and obesity.

Previous research already had found other flame retardants – now-banned brominated compounds used in upholstered furniture and electronics – in fish and wildlife near McMurdo Station’s wastewater outflow.

Indoor dust that makes its way down the drain may be one culprit, Chen said. The chemical was detected in dust inside the two research stations at concentrations comparable to levels reported in dust in each base’s home country.

The U.S. station treats its wastewater to promote bacteria that break down human sewage, food and soaps. The water is then released into McMurdo Sound, while the sludge is sent back to the U.S. But the treatment process does not entirely remove flame retardants and other persistent organic pollutants.

At the other end of the world, HBCD also has been found in Arctic wildlife, including killer whales, gulls and polar bears. Levels found in the Antarctic animals near the research stations were lower than in animals in most of North America and Europe. But they were comparable to average levels found in some wildlife in the Arctic, which is more populated by humans than Antarctica and more vulnerable to chemicals originating in the Northern Hemisphere.

Antarctica’s Adelie penguins have similar HBCD levels as Arctic birds, the researchers found.

The discovery upends the notion that contamination of the Antarctic occurs mainly from chemicals transported long distances by winds and ocean currents. In contrast, in the Arctic, most chemicals contaminating people and wildlife originated elsewhere.

“The findings from these studies are novel, because we usually assume that pollution in Antarctica is long distance,” said Gregory Howard, an environmental scientist who researches flame retardants at Dickinson College in Pennsylvania.

How bad is the contamination? “You have a concentrated area that has been pretty heavily impacted by flame retardants and other persistent contaminants over the years, but by North American standards, the footprint is pretty small,” said Robert Hale, a toxicologist at the Virginia Institute of Marine Sciences who co-authored the study with Chen and and Stacy Kim of the Moss Landing Marine Laboratories.

In the 1990s, countries with interests on the continent implemented a treaty aimed at preserving the Antarctic environment. Included were bans on the use of certain chemicals, such as polychlorinated biphenyls (PCBs), known to persist in the environment and harm people and wildlife.

However, the treaty neglects newer groups of chemicals, such as flame retardants, which have since become chemicals of concern.

“Our data suggest that the treaty protocol is not sufficient to protect the Antarctic environment from all persistent chemicals,” Chen said.

The U.S. is investigating alternatives to HBCD, and the United Nations has recommended that it be phased out globally. But there’s likely no easy solution to the Antarctic problem.

“We can ban or restrict the use of one thing, but we are introducing new chemicals all the time whose environmental and health impacts we know very little about,” Howard said.

Antarctic researchers try to reduce their impacts on the continent.

“We take tremendous steps to keep our footprint as small as possible, and we’re doing a pretty good job,” said Wayne Trivelpiece, a scientist with the U.S. National Oceanic and Atmospheric Administration who has been studying penguins in the South Shetland Islands of the Antarctic Peninsula since 1976.

However, it hasn’t always been that way. Before the late 1980s, some bases dumped trash into the bay or burned it, Trivelpiece said.

Now everything except for their wastewater and organic food waste leaves with them, he said. In 2002, they switched from gasoline generators to solar and wind power for their small base.

Rotella, a Montana State University scientist who has been coming to Antarctica since 2002, said no trash gets left behind now. From the bamboo wands used to mark the snowmobile trails to their study sites to the smallest bit of rope or plastic, “it all gets carried off the continent,” he said.” Even the tiny exhaust marks that our machines leave in the snow get scooped up and sealed in bags to come home.”

“It’s one of the only places left where we can study a system that is pretty much intact,” Rotella said. “It’s critical to preserve that.”