LCW Deicing Salt Reduction​

Aquatic Impacts:

• A low nutrient body of water can experience impacts to algae (the base of the aquatic foodweb) at as little as between 2-10 mg/L , while other bodies of water with higher nutrient levels  may not have an impact until  levels reach 70+ mg/L.  

• An increase in chloride levels will shift algae dominance from chlorophyte (green algae) to cyanobacteria (blue-green algae), which can lead to toxic algal blooms.

• Sensitive zooplankton species are impacted at 210 mg/l, which can cause a trophic cascade impact that can increase phytoplankton populations potentially causing toxic algal blooms,

• There is a shift in sensitive macroinvertebrate populations at 220 mg/l.

• Vermont chronic level of impact is 230 mg/l,

• The EPA standard not to exceed 250 mg/l,

• And Native brook trout populations are impacted at 250 mg/l,

 

Many streams within Vermont have already been identified as impacted by chloride through water quality monitoring efforts and exceed EPA standards and levels that would impact brook trout populations. 

For reference, some stream data collected in the summer, during low flow, sampled under the Chittenden County Stream Team:

• Indian Brook average 240 mg/l

• Engelsby Brook average 410 mg/l

• Pottash Brook average 430 mg/l

• Centennial Brook average 560 mg/l

• Sunnyside Brook average 630 mg/l    

 

The addition of sodium chloride to waterways impacts the movement of metals, causing toxic accumulation. Chloride joins with metals (mercury, lead, copper) making them more water soluble and bioavailable.

 

The addition of sodium chloride to our waterways can release sediment bound heavy metals back into the water column. The density of the water can be altered, impacting how a lake turns over in the spring and fall causing anoxic or dead zones within the body of water.  Under these conditions mercury, phosphorus and heavy metals can be released from the lake sediment.     Normal stratification of lakes returns after the reduction in road salt loading.

 

Terrestrial Impacts:

• Soil bacteria near roadways are impacted at 90 mg/l.

• Impairment to seed germination takes place at 100 mg/l

• The sodium chloride will also strip the soils of calcium, magnesium and other important components needed for healthy soils.  This can allow for invasive species to take hold.

• Road salt can cause drought conditions by limiting available water in soils and trees.

• It is not hard to find damage to trees along roadways.  Sodium chloride burns the needles and leaves of species within 15 feet of roads and can impact sensitive plant species as far away as 650 feet. 

• Road salt attracts wildlife to the road increasing the risk of animal related collisions.

• There have been many reported bird kills from eating the road salt within the U.S. and Canada.

• Sodium Chloride that enters wetlands and vernal pools can alter sex ratios of species of frogs and decrease the development of eggs thereby pushing already threatened species to the brink.