Spillin’ Salt: Pitt’s winter maintenance

Keeping the streets and sidewalks safe for Pitt students and faculty is no easy — or cheap — task.

High concentrations of sodium can mobilize or release calcium and magnesium from the soil. This transports the particles into the groundwater or the surface water, depending on the flow passage through the dirt, according to Robert Rossi, a graduate student researching how road salt impacts roadside soils.

Similarly, exhaust pipes and worn tires from cars deposit heavy metals such as lead, zinc and arsenic, and high concentrations of sodium can mobilize and transport these into the stream waters or ground waters. Rossi said the excess salt affects aquatic life, vegetation health, animals and water quality.

“If we are thinking of the environment as that which can support humans, [salting the roads] is probably worth the cost in terms of human safety,” Daniel Bain, assistant hydrology and metal biogeochemistry professor, said. “But it’s probably going to affect everything else negatively.” 

For an average snowfall of two to four inches, Pitt’s Buildings and Grounds Department covers 30 miles of campus sidewalks, more than 2,000 steps and 40 campus parking lots with salt, according to Pitt spokesman John Fedele. This task uses 20 tons of road salt and 1,000 bags, or  25 tons, of ice melter, Fedele said in an email. To put things in perspective, Fedele said Pitt’s sidewalks, placed end to end, would stretch from campus to Weirton, W. Va., and, stacked together, Pitt’s steps would reach the observation deck of the Empire State Building. 

The University has a $135,000 yearly budget for the salt and started off the winter season with 90 tons of road salt and 3,200 bags, weighing 80 tons total, according to Fedele. Last year, Pitt used 630 tons of road salt and 22,600 bags, weighing 565 tons total, which cost $200,467.  

To make up for last year’s costs exceeding the budget for salt, the University “deferred the purchase of other materials and or equipment as needed,” Fedele said. 

Those deferred purchases have not hurt the University, Fedele said.

“Snowfall so far this year has been less than anticipated, so our salt usage is below where we expected.”

The Pittsburgh Department of Public Works had a busy season last winter, too. 

 Pittsburgh uses 42,000 tons of salt for a normal snowfall. Based on Pittsburgh’s average of 42 inches of snow per year, the city spends approximately $4,200,000 on salting the streets, according to Public Works Director Mike Gable. 

“We used 63,000 tons of salt in the 2013-2014 season and spent about $3.5 million on salt alone,” Gable said.

The University uses two separate materials for de-icing: sodium chloride, or rock salt, and a blended material of rock salt coated with calcium magnesium, according to Pitt spokeswoman Cara Masset. The type of surface and weather conditions dictates which material the University uses. 

But all that salt has to go somewhere, and, according to Bain, there’s a trade-off with salting the roads.

“Adding a lot of one thing [such as salt] in a concentrated way is probably not good for any part of our environment,” Bain said. 

Masset said that, in an attempt to reduce the impact on the environment, Pitt’s grounds crew uses only the volume of material that is required for a particular storm. 

“We are attempting to reduce the amount of de-icing material used,” Fedele said.

According to Rossi, most transportation departments use sodium chloride for keeping roadways and sidewalks safe because it’s the cheapest. However, he said the downside to using sodium chloride is that the chloride is the main component in mobilizing metals and transporting them into stream or ground waters.

Rossi said that alternative salts, such as calcium chloride, magnesium chloride and calcium magnesium acetate, can clear the roads. 

Pitt uses calcium chloride or magnesium chloride/sodium chloride blend products depending on the sidewalk, according to Fedele.

These salts, however, are more expensive and don’t work as fast as sodium chloride. Calcium magnesium acetate is relatively better for the environment, according to Rossi, because it doesn’t contain chloride, the main component that mobilizes metals. 

“Calcium chloride works at lower temperatures, but you have to put more of it down, so it doesn’t work as fast as sodium chloride,” Rossi said.

Masset said anti-icing methods prevent snow and ice from bonding to surfaces, increasing the effectiveness of plowing, shoveling and sweeping. 

There are other methods, apart from salting the streets and sidewalks, to help clear the snow. 

According to the Salt Routing System, the DPW classifies streets into three categories: primary, secondary and tertiary. 

“Streets around the Pitt campus are both primary and secondary with the hospitals having emergency routes due to their special need,” Gable said. “Emergency routes are a portion of a primary route.”

Additionally, to optimize salt application rates, some people have suggested anti-icing as opposed to de-icing.

For anti-icing, salt is put down before the snow begins so that, when it snows, the snow melts right away and can be removed easily. De-icing, on the other hand, is when salt is only put down after it snows, so the salt sits on top of the snow and builds up.

 “It’s more of a manpower issue with anti-icing, because you would have to mobilize in advance,” Rossi said.

Another tactic, according to Bain, is to add traction so that not as much salt needs to be used.

 “You can use things that are more benign, things that don’t dissolve, like sand and grit,” Bain said. “That can help some, but it doesn’t help remove snow — it just adds traction.”

While the University has to consider the environment when determining salting methods, some students have alternative thoughts. 

Katie Otto, a freshman majoring in chemistry, said the excess salt has an impact on her fashion choices. 

“The excessive salt on the streets has certainly affected my day-to-day choice in footwear,” Otto said. “The salt ruins [my] shoes. It can damage the soles and the tops of the shoes. Not to mention all the slush messes up the shoe.” 

 Rossi has his own salt-removing concoction. He suggests using a solution of 50 percent vinegar and 50 percent water to remove the white stains caused by road salt. 

“I’ve been doing it because I destroyed my one pair of boots already,” Rossi said. 

But Otto has changed her everyday footwear because of the salt. 

“My default footwear ends up having to be big, clunky boots when I would rather be wearing some of my more stylish footwear,” Otto said.

Despite the effects salt has on both the environment and pedestrians’ shoes, Bain is concerned that, if salt were removed from the system, there could be immediate and potentially painful consequences for walkers. 

“If it were up to me to keep a set of stairs clean from snow, and I could potentially lose my job if someone slipped and broke their arm, I’m going to over salt,” Bain said. “Given that responsibility structure, I don’t think there’s a way to remove salt from the system easily.”