Polar Bears Are Consuming Less Mercury—But There's a Downside

Ansgar Walk, Wikimedia Commons // CC BY 2.5
Ansgar Walk, Wikimedia Commons // CC BY 2.5

Scientists studying mercury levels in polar bears say that melting sea ice has forced the bears to change their diets. The researchers published their study in the journal Environmental Science & Technology.

Mercury is all around us. Some of it occurs naturally in plants, animals, and the soil. Some of it is our fault, the result of industrial pollution from coal and other fuels.

Regardless of its source, it piles up in living things the same way. Tiny animals eat plants containing mercury, and the mercury stays in their bodies even after all the plant matter is gone. Then those tiny animals are eaten by small animals, and on and on, onward up the food chain. Apex predators like swordfish and sharks are swimming globs of mercury, which is why we tell pregnant women not to eat them.

For the same reason, they shouldn’t eat polar bears, either (although we would kind of like to see them try). Previous tests on bears in the southern Beaufort Sea found alarmingly high mercury levels in the animals’ hair and body tissue—the result of the bears’ diet of mercury-saturated ringed seals. Or their former diet, we should say.

Researchers followed Beaufort Sea bears from 2004 to 2011, taking regular tissue and hair samples from sedated bears and by long-distance biopsy dart. Chemical analysis of the samples showed a clear and steady decline in mercury levels. Each year, the bears’ bodies contained 13 percent less mercury.

But it’s not as though these bears were getting 13 percent smaller. They weren’t wasting away. So what had happened?

It turns out their main prey, ringed seals, had grown scarce. Ringed seals spend most of their time on sea ice. But as the sea ice disappeared, so did they. In response, the bears shifted their predatory attention to bearded seals and bowhead whales, both of which carry less mercury. Even as their mercury levels dropped, the bears' BMI increased, perhaps because they were eating more blubber from the larger prey.

The authors note that the bears in their study might not represent all bears in that region. They could only take samples from the bears they could find along the coast. Less successful hunters might still have been struggling out at sea.

They also say that the polar bears’ prey-switching is, sadly, not a sustainable solution. We’re not exactly experiencing a surplus of whales, here.

Oregon Launches the Country's First State-Wide Refillable Beer Bottle Program


Being a frequent beer drinker doesn't just affect your waistline. It's also not good for the environment—all those cans and bottles add up. But Oregonians soon won't have to feel guilty for the bottles piling up in their trash cans, because the state just launched the first state-wide refillable beer bottle program in the U.S., as NPR and EarthFix report.

Oregon breweries are selling their beer in thicker, heavier beer bottles that customers can return to be cleaned and refilled, just like the milk bottles of yore. Seven craft breweries whose beers are available in stores across the state are currently participating in the refillable bottle program, but the distinct bottles can be used and refilled at any brewery in the state, and the program will likely expand in the coming years.

The bottles, stamped with the word "refillable," are made from recycled glass and can be reused up to 40 times. The design was developed by the Oregon Beverage Recycling Cooperative, and customers can drop them off at any of the group's 21 redemption centers. The organization also runs the state's general container deposit-refund system, so customers can bring them to the same locations as any other recyclables.

The thicker shape allows them to be separated out from other recyclables that get dropped off at bottle deposit sites, ensuring that they get sorted out to be refilled rather than recycled with standard glass bottles.

Oregon passed the first state bottle bill in the nation in 1971 as a way to encourage recycling. In 2018, the state increased the bottle deposit from 5 cents to 10 cents, hoping to increase redemptions. About 73 percent of metal, glass, and plastic recyclables were actually redeemed in 2017, up from 64 percent in 2016.

While refillable beverage containers aren't the norm in the U.S., other countries are far ahead of us. Some provinces in Canada have nearly a 99 percent return rate for their refillable bottles, and the average bottle is reused 15 times. Most beer in Germany is sold in mehrweg, or reusable, bottles, and consumers can return them to any store that sells reusable-bottle beer to get their deposit back.

Though the Oregon program is an environmental boon, the carbon savings won't be as high as they could be. Oregon doesn't yet have a bottle washing facility to process the refillables, so they currently have to be shipped to Montana for washing. Eventually, the program will set up some of these washing facilities in-state, increasing its utility.

[h/t NPR]

You Can Visit Any National Park For Free This Saturday

Mark Ralston, AFP/Getty Images
Mark Ralston, AFP/Getty Images

Looking for something to do this weekend? Within driving distance of one of the country's more than 400 national parks? The timing might work out. On Saturday, September 22, the National Park Service will be celebrating National Public Lands Day by offering free admission to any national park that normally charges an entrance fee.

Established in 1994 by the National Environmental Education Foundation, National Public Lands Day is held annually on the fourth Saturday in September. The day is set aside to recognize and encourage stewardship of green space in individual communities. If you see an opportunity to volunteer that day, you can get a voucher good for admission on a day of your choosing.

Admission to federally owned parks during peak season averages $30 at the 117 locations that require payment for access. Recently, the National Park Service had considered raising the fee to $70 at 17 of the busiest parks. The potential move would help address maintenance and other costs, but it's drawn criticism from conservation groups arguing the locations should remain affordable to visitors. In the end, the NPS decided to raise prices by $5 for one-time entry, or $5 to $10 for an annual pass, though some fees won't rise until 2020.

You can search for parks by state or by activity using the National Park Service Find a Park search engine here. Note that any additional charges for camping or other attractions aren't included in the promotion.

Can't make it this weekend? The parks are open for a fee-free day four times in 2018, down from 10 in 2017. The next date is November 11, in honor of Veterans Day.