Tainted water can skew population toward males, study reveals – via Herp Digest

By Brian Nearing Thursday, November 24, 2016, Albany Times-Uniion

Salted frog may sound like a gourmet restaurant dish, but it actually could mean real trouble for coming generations of the amphibians.

New research done by Rensselaer Polytechnic Institute and Yale University has found that road salt finding its way to pools where frogs breed tilts the balance of offspring, resulting in more males and fewer females that emerge as tadpoles.

"How the salt is doing this, frankly, we don't yet know," said Rick Relyea, a RPI biologist and co-author of the study that was published this month in a Canadian aquatic science journal. "How many females you have in a population determines how many offspring you have. We are not in a position to make any conclusions about potential population decline, but what we do not need is more males.”

Normally, the ratio of male to female tadpoles is roughly equal, said Relyea, who runs the RPI Aquatic Laboratory in North Greenbush, where he conducted the frog study over the last year using massive 500-liter water tanks.

Some tanks contained leaves from oak and maple trees, which are common around

the forest pools where frogs and other amphibians lay their eggs.

Other tanks contained road salt, which is routinely applied to highways in the winter.

Some salt can get washed into drainage systems and potentially reach other bodies of water. For example, Lake George salt levels have been rising steadily.

During the last three decades, the lake's salt levels have tripled, making it now about 30 times saltier than an undeveloped Adirondack lake.

The problem is happening throughout the Adirondacks wherever there are roads, according to Dan Kelting, executive director of the Adirondack Watershed Institute at Paul Smith's College. He spoke at a regional summit last year aimed at addressing the growing threat of road salt.

In the salted water tanks at the RPI lab, there were 60 male tadpoles for every 40 females — a shift of 10 percent. The effect is called masculinizing. Also, female tadpoles exposed to salt were smaller than normal.

"The continual masculinization of frog populations for many generations in habitats contaminated with high concentrations of road salt ... could potentially affect the abundance of frogs in these habitats," said Relyea, who is also director of RPI's Darrin Fresh Water Institute.

"The research raises the possibility that many other aquatic species could be affected by road salts in sub-lethal ways, not only in terms of altered sex ratios, but potentially in many other traits.”

His experiments were conducted as part of the Jefferson Project at Lake George, a research collaboration among RPI, IBM and The Fund for Lake George, a not-for-profit advocacy group. The project is currently installing a series of water- and land-based sensors around the lake to study its water quality and ecosystem.

Part of that ecosystem includes what are called vernal pools, which are temporary pools of water that routinely form by snow melt in the spring, and where frogs and other amphibians lay eggs. "The vast majority of our amphibians come from vernal pools, not lakes," said Relyea. There are likely hundreds of such pools surrounding the lake, where road salt is applied every winter.

"When it comes to road salt, frogs are like canaries in a coal mine warning us of the need to dramatically cut back salt use," said Eric Siy, executive director of The Fund for Lake George. "An estimated 30,000 metric tons of road salt is applied annually in the Lake George basin — enough to fill 300 rail cars or a train 3 miles long every year.”

Across the U.S. each winter, more than 22 million metric tons of salt is applied on roadways, according to estimates by RPI.

Siy's group just held its second annual "salt summit" at the lake, where local officials and conservationists learn about potential methods to reduce use of road salt during the winter.

Previous studies have found effects on amphibian gender ratios caused by exposure to pharmaceuticals and pesticides, but the road salt study is the first of its kind.

"The health and abundance of females is obviously critical for the sustainability of any population because they're the ones that make the babies. So if you have a population that is becoming male-biased, the population might be at risk," said Max Lambert, lead author of the research study and a doctoral student at the Yale School of Forestry and Environmental Studies.

Other researchers included Aaron Stoler, a postdoctoral researcher at RPI, and Yale researchers David Skelly and Meredith Smylie.

Lambert said previous research suggests that such outcomes could be caused by a phenomenon in which simple elements — such as sodium — can bind to a receptor in cells, mimicking the actions of testosterone or estrogen.

This, in turn, can trigger masculinizing or feminizing functions.

"So there is a very small testosterone-like effect with one salt molecule," he said. "But if you're dumping lots and lots of pounds of salt on the roads every winter that washes into these ponds, it can have a large effect.”

Rivers in wintry cities remain salty year-round - via Herp Digest

By Brian Bienkowski, Staff Writer, Environmental Health News, December 19, 2013

As winter sets in across the northern United States, the road salt that keeps people out of ditches is flowing into rivers at levels that could harm fish and other creatures.

With billions of pounds of salt spread on U.S. roads every year, waterways in the nation’s wintry cities are getting saltier. And, according to new research, the salt, or sodium chloride, in rivers remains toxic not just in winter, but throughout two-thirds of the year.

More than 116,000 people are injured on U.S. snowy or icy roads every year.

In icy Wisconsin, where salt is liberally dumped on roads, the Menomonee and the Kinnickinnic have chloride levels in late winter and early spring 10 to 15 times higher than a federal level set to protect fish, amphibians and tiny crustaceans. Toxic concentrations also have been found in rivers, streams and lakes in New York, Maryland, Minnesota, Missouri and several other states.

“It’s likely that many of the organisms in rivers that are sensitive to chloride are simply no longer there,” said Steve Corsi, a research hydrologist with the U.S. Geological Survey.

Seven of 20 U.S. rivers – four in Wisconsin, one in Ohio and two in Illinois – have average chloride levels that approach or exceed the Environmental Protection Agency’s guideline for protecting aquatic life, according to the USGS study, which is not yet published. All seven rivers exceeded it on more days in 2006 than in 1991.

In addition to posing a threat to wildlife, the salt can leach into groundwater, contaminating drinking water supplies.

The salt stays in rivers and groundwater for years after it’s tossed on roads, said Sujay Kaushal, an associate professor at the University of Maryland who studies road salt in Northeast U.S. streams.

In addition to posing a threat to wildlife, the salt can leach into groundwater, contaminating drinking water supplies. “Even if they quit applying salt now, it would take decades for it to be removed from the system,” Kaushal said.

Yet road salt is considered a necessity in northern states. It is the most efficient and economical way to keep people safe in the winter, said Morton Satin, a vice president at the Salt Institute, a non-profit trade association that advocates for salt.

“We have chosen to live in a northern climate, where we want the same safety in the winter that we have in the summer,” Satin said. “Amazon has to deliver the same packages even when the roads are bad.”

More than 116,000 people in the United States are injured and more than 1,300 killed on snowy or icy pavement each year, according to the U.S. Department of Transportation. Road salt reduces snow-induced crashes by about 88 percent, says a Marquette University study.

Volumes of salt applied to roads have been increasing since the 1940s.

Salt lowers the freezing point of water, preventing ice and snow from sticking to roads. In addition, cyanide compounds, which also can be toxic, are often added to road salt to prevent it from caking.

The volumes used on U.S. roads have increased each decade since the 1940s. About 617 million pounds were sold per year in the 1940s, and now roughly 35 billion pounds per year.

Some cities, including Madison and Milwaukee, have experimented with beet juice, sand and other “greener” ways to keep ice off roads. But most deicers still contain some chloride, Corsi said. “You may not need to apply as much of them, but they’re way more expensive.”

In Minnesota, the salinity of 39 lakes has mirrored the upward trend of the state’s purchase of road salt. If this trend continues, salinity will double in these lakes in about 50 years, according to University of Minnesota scientists.

In the new USGS research, the rivers were saltiest in the late winter. But the Menomonee and the Kinnickinnic had high concentrations in the summer, too, Corsi said.

“Chloride is very soluble and it’s easy for it to infiltrate the groundwater, the source of the river flow,” said Corsi, who was lead author of the study.

The new findings build on previous USGS research that found that more than half of sites tested in 13 U.S. cities exceeded the EPA’s chloride guideline of 230 parts per million, according to a 2010 USGS study. That guideline is based on chronic exposure levels that reduced the survival of water fleas, rainbow trout and fathead minnows.

Streams tested in Maryland, New York and New Hampshire were “well beyond” the toxicity guideline, Kaushal said. In Missouri, an urban stream, Hinkson Creek, had high levels of chloride linked to reproductive and survival problems for water fleas.

Some of the creatures most sensitive to chloride are amphibians, which are declining worldwide from a variety of environmental threats.

"Road-side aquatic ecosystems in North America are annually polluted with millions of tons of road deicing salts, which threaten the survival of amphibians which live and breed in these habitats,” Utah State University researchers wrote in a study published earlier this year.

Newts exposed in the Utah laboratory to amounts of salt commonly found in roadside streams had severe developmental deformities – bent tails, bent bodies, cysts, missing tails and gills, two heads and shrunken heads.

Also, salamander eggs develop abnormally when exposed. They cannot retain the water needed to avoid freezing and disease.

Wisconsin does not regulate road salt use, and the levels showing up in the state’s rivers are concerning, said Tim Asplund, a monitoring section chief with the Wisconsin Department of Natural Resources.

“There are other contributors to chloride concentrations … wastewater treatment facilities, industrial discharges. “But it’s very likely due to road salt.” –Tim Asplund, Wisconsin Department of Natural Resources 

The state agency, which has been monitoring 42 river sites since the 1980, has found increasing chloride concentrations.

“There are other contributors to chloride concentrations … wastewater treatment facilities, industrial discharges,” Asplund said. “But it’s very likely due to road salt.”

Satin said the salt industry has long known its “biggest long-term problem would be chloride running off into water.”

There are ways to minimize the runoff impact, he said.

“We encourage people to only use the lowest amount they need,” Satin said. “Also, as a country we have not re-engineered our road system in 50 years, we need to take runoff into account in our road design.”

Kaushal agreed, saying that ensuring protection of wetlands and vegetation “provides some line of defense before things get into the river.”

“We need to ask ourselves if we should really be putting more highways, parking lots and houses right on top of rivers.”