Water Quality/Wetlands

The Colorado Department of Transportation’s Division of Aeronautics recently wrapped up a two-year effort to help certified commercial service airports statewide acquire equipment to minimize the environmental impact of aircraft firefighting foam containing toxic chemicals known as per- and polyfluoroalkyl substances or PFAS.

[Above photo by the Colorado DOT]

The Colorado Aeronautical Board, which oversees the Colorado DOT’s Division of Aeronautics, approved $400,000 in state aviation funding to assist with this equipment swap effort – only the second such program in the nation – in collaboration with state airports and the Colorado Department of Public Health and Environment.

This effort comes amid an increasing environmental focus on PFAS chemicals, which pose challenges to drinking water reserves.

For example, the Senate Committee on Environment and Public Works held a hearing in October to assess ongoing and proposed responses to the presence of PFAS chemicals in the environment, particularly in U.S. waters, by the Environmental Protection Agency.

Radhika Fox, the EPA’s assistant administrator for water, noted in her testimony at that hearing that a “growing body of scientific evidence” shows that exposure at certain levels to specific PFAS can adversely affect human and ecological health. Studies indicate that two common

PFAS – perfluorooctanoic acid and perfluorooctane sulfonate – can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals. Both chemicals also caused tumors in animal studies, she said. Fox added that the most consistent findings from human epidemiology studies are increased cholesterol levels among exposed populations as well as some cases where that chemical family affected birth weights, the immune system, caused cancers, and thyroid hormone disruption.

Currently, commercial service airports certified under Federal Aviation Administration regulations are required to use PFAS-based foam and to annually test and certify aircraft rescue firefighting equipment and the foam utilized.

Under the provisions of this new statewide aviation initiative, however, the Colorado Division of Aeronautics said in a statement that it provided 100 percent funding for the acquisition of specialized testing and containment equipment designed to allow FAA-compliant firefighting foam testing to take place without the need for regular foam discharges. 

In total, 12 eligible airports participated in the division’s program, with the exception of Denver International Airport, as it already had the equipment, and Colorado Springs Airport, where the U.S. Air Force provides aircraft rescue and firefighting services.

When it snows in Minnesota, drivers want the roads and bridges cleared – now.

However, simply dumping mass amounts of salt on the roads is an outdated practice for the Minnesota Department of Transportation. Today, the agency is taking a new strategic – and more environmentally friendly – approach to how it removes snow and ice.

[Above photo by the Minnesota DOT]

“We want to minimize what we use,” explained Sue Lodahl, Minnesota DOT’s acting state maintenance engineer. “It’s about using the right chemical at the right time in the right location.”

During the 2020-2021 winter season, the agency spent $116 million and used more than 800 plow trucks and 354 million pounds of salt to combat 53 inches of snowfall, according to the department’s Annual Winter Maintenance Report. The salt usage was down about 15 percent from the previous year.

[To learn more about snow and ice fighting tactics, check out the winter operations podcast put together by the American Association of State Highway and Transportation Officials Snow and Ice Pooled Fund Cooperative Program, known as “SICOP.”]

The Minnesota DOT has also published “Winter Maintenance Best Practices,” a guide for using salt, with an emphasis on sustainable practices. “MnDOT seeks to reduce the use of salt on roadways while maintaining a high level of performance with regard to level of service recovery in winter operations,” the guide states.

The department’s Salt Solutions Program helps operations personnel make good decisions about selecting the best and safest materials for clearing the roads. As a result, the Minnesota DOT’s maintenance crews now have an arsenal of tools to fight snow and ice – including salt, potassium acetate, calcium chloride, sodium acetate and even beet juice.

[Editor’s note: The Minnesota DOT also began testing the technology on 10 of its snowplows in January that allows operators to activate digital highway signs to warn motorists when slow-moving vehicles are ahead on the road. That technology activates digital message signs to display certain messages as they pass, such as “Snowplow ahead, use caution” or “Maintenance vehicle ahead, use caution” during non-snow events. The message stays activated for several minutes after the snowplow passes the sign.]

Even with all the chemical options available, plain road salt – sodium chloride – is still the “go-to” material, yet it has its limitations. Salt is not effective if the temperature drops below 15 degrees Fahrenheit.

Moreover, if salt washes off the road, it can harm water, vegetation, and wildlife.

“We’re always going to use granular salt, but we’re trying to keep it on the road,” Lodahl said. “You can’t just put down salt. Otherwise, it will go into the environment.”

The Minnesota DOT also “pre-wets” the salt with truck sprayers just as it hits the road. The water helps the salt stay on the roadway, where it reacts to the heat from vehicle tires. “But if the temperature is less than 15 degrees, that’s when we move into calcium chloride,” Lodahl pointed out.

The department’s top priority is to achieve what it calls “bare lanes,” a condition in which 95 percent of the lane between the wheel tracks is free of snow and ice and travel speeds are not impacted. Last winter, the Minnesota DOT saw bare lanes 87 percent of the time. The Salt Solutions Program’s goal is to strike a balance between achieving bare lanes and protecting the environment.

In 2020, the agency also studied using potassium acetate almost exclusively on roads in Duluth, where the average daily winter temperature is 23 degrees. The study showed promise, but there are still some environmental unknowns about the long-time use of potassium acetate, Lodahl said.

“Salt is still our biggest tool, our best tool,” she explained. “Everything is going to have some environmental factor. If salt scatters, it’s not doing us any good, and it harms the environment.”

Lodahl added that salt sustainability “is very important to MnDOT. We cherish the environment and try to keep the roads safe.”

A pair of new exhibits at the Tennessee Aquarium funded by the grants from the Tennessee Department of Transportation illustrate how microplastics and other roadside trash can negatively affect the health of the ocean as well as rivers, lakes, and streams.

[Above photo by the Tennessee Aquarium]

The new exhibits – housed in the Aquarium’s “River Journey” and supporting the Tennessee DOT’s “Nobody Trashes Tennessee” litter reduction campaign – includes actual debris taken from the banks of the Tennessee River

The exhibits demonstrate the connection between land-based pollution and aquatic ecosystems through “touchless” interactive elements, informative videos, and an exhibition of invasive aquatic wildlife such as a Northern Snakehead and Grass Carp. Those non-native fish are housed in one of the exhibits, swimming alongside examples — some of them 3D-printed — of common roadside debris such as tires and car batteries, which can wreak havoc on aquatic systems.

“The connections between roadside litter, water quality and aquatic systems cannot be understated,” said Shawn Bible, Tennessee DOT’s beautification office manager, in a statement.

“The ‘Nobody Trashes Tennessee’ campaign aims to educate citizens on the impact of what may be perceived as a minor issue for the state,” Bible added. “In reality, the state spends more than $19 million each year to clean up the more than 100 million pieces of litter on our roadways. We are pleased to partner with the Tennessee Aquarium on these interactive exhibits.”

The exhibits help visitors visualize how trash can imperil aquatic ecosystems and impact waterways that millions rely on for recreation and drinking water, while also demonstrating how changes in behavior on land can benefit the health of nearby waterways, explained Dr. Anna George, the Aquarium’s vice president of conservation science and education.

“Anything that is on land moves into our waterways,” Dr. George said. “If a piece of litter is thrown onto a street, wind might carry it to a stream or river. It might get washed or blown into storm drains and deposited in the nearest body of water. It is a safe assumption that any debris on land has a good chance of winding up in our water.”

According to the National Oceanic and Atmospheric Administration, 80 percent of garbage found in the ocean comes from inland sources, such as leaked automotive fluids and littering. “So even though the [Tennessee] Department of Transportation might seem like an odd partner for an aquarium, there’s a fundamental connection between activity on land and the health of waterways,” Dr. George noted.

The Washington State Department of Transportation recently wrapped up a roughly $13 million fish barrier correction project – resulting in a new 440-foot bridge that spans Kilisut Harbor along State Route 116. The new bridge not only improves safety for human travelers but also is, in the words WSDOT Project Engineer Dan McKernan, a “huge win” for local salmon and other fish species in the area.

[Photo courtesy of Washington State Department of Transportation.]

“The work involved replacing two small culverts that were installed in the 1950s. The channel here now with the bridge was not here previously,” he said, adding that the new channel aids in the annual migration of salmon in the area.

This work is part of WSDOT’s Fish Barrier Removal Program, which identifies and removes barriers to fish caused by culverts under state highways. The agency noted in a statement that it worked with the North Olympic Salmon Coalition or NOSC to complete this specific bridge project while also continuing to work with the Washington State Department of Fish and Wildlife to identify locations where culvert replacement will increase fish habitat.

“The area between Indian and Marrowstone Islands was historically comprised of tidal channels and salt marsh,” NOSC noted in separate statement. “Tidal waters exchanged freely between Oak Bay and Kilisut Harbor, flushing cold water, moving sediment, and allowing juvenile salmon to migrate northward from Oak Bay into the shallow, productive waters of Kilisut Harbor. The installation of the causeway in between Kilisut Harbor and Oak Bay eased transportation between the Islands, but choked the flow of water and sediment, eventually creating an artificial beach berm, a filled channel, and increased water temperatures in Kilisut Harbor.”

The construction of the new bridge also resulted in the removal that land barrier, reconnecting the large numbers of Hood Canal and Puget Sound out-migrating juvenile salmon that converge at Oak Bay with immense foraging opportunities available within Kilisut Harbor while also restoring and enhance important staging and foraging habitat for multiple coastal dependent and migratory birds. “Clean, cold water is now flowing north into Kilisut Harbor/Scow Bay,” the organization noted. “This mixing on each tide cycle is expected to improve water quality in Kilisut Harbor over time.”