With temperatures becoming more wintry and snow falling in parts of the state this week, the Minnesota Pollution Control Agency has issued a plea to homeowners about salting their sidewalks.
It is calling on people to limit the amount of salt you use when clearing sidewalks and driveways of snow and ice, because of the potential it has to pollute the state's lakes, rivers and water supplies.
It says that rock salt, which is also used by the state's road salting teams, may have safety benefits but they also have environmental drawbacks – polluting waters and poisoning aquatic wildlife.
The MPCA estimates that 78 percent 0f the salt applied to roads and paving in the Twin Cities metro stays within the area's watershed, with chloride from the salt eventually finding its way into the groundwater supply.
"Too much chloride has serious water quality consequences." Brooke Asleson, chloride project manager at the MPCA, said in the press release. "Less is more when it comes to applying deicing salt. It only takes one teaspoon of road salt to pollute five gallons of water."
The MPCA is partnering with metro area counties to more effectively protect waters from salt pollution, but in the meantime has several suggestions for how homeowners and drivers can reduce their salt use:
- Shovel the snow and ice before salting, meaning you have to use less.
- Apply salt before snowfall, which prevents snow and ice from building up.
- Slow down and be patient behind slow-moving plows – the slower they drive, the more salt stays on the road.
- Stop applying salt at below 15 degrees – it stops working. Use sand instead for traction.
- Don't use too much – no more than 4 pounds is required for a 1,000 square foot area.
- Sweep up leftover salt after snow/ice has melted – it's no longer serving a purpose.
Mashable reported last year that in the metro area every winter, the equivalent of 260 pounds of salt per person is used by authorities.
A previous MPCA study found that 39 water bodies in the metro area were found to have higher salt levels than the water-quality standard.