The #'s Behind (road salt) & Chloride

The winter has begun and we are all anticipating snow. While most of us are waiting to enjoy our favorite past time in the woods, be it cross-country skiing, or snowshoeing, we all need the fluffy abundance of snow. The down side may be driving in it. Road salt application is not linked to snow amounts, but to the chance of ice, or snow melting and refreezing on the road. While many of our municipalities follow road salt application best management practices, there are new tools and methods out there. Homeowners and private contractors should also follow BMP's. The serious impact from road salt application is when it runs off into our streams. Here are some numbers to make us think.

~ The EPA has set a limit on drinking water sources to 250 mg/L

~ VT Proposed state standard 230 mg/L (EPA chronic criterion)

~ Those with hypertension should not drink any water with a level of 20 mg/L or higher

~ Roadside vegetation is damaged when levels reach at or above 70 mg/L

~ Soil bacteria (the healthy parts) are impacted at 90 mg/L

~ The base of the aquatic food chain (algae and macro inverts) are impacted at 12mg/L

~ Native Trout populations are impacted at 250 mg/L

~ There is a shift in sensitive populations of organisms within a stream at 220mg/L

The Sodium-Chloride levels that enter our bodies of water can interfere with fish spawning, degrade in-stream habitat, create areas that invasive species can take hold and impact our sensitive native upland species including the sugar maple.

Why are these numbers important?

During the most recent stream surveys conducted by the Chittenden County Stream Team and the Friends of the Winooski, they monitored chloride levels within 8 different streams.

The sampled streams data can be found on the Chittenden County Stream Team's website at: http://www.ccstreamteam.org/

A brief Summary of a selection of sample sites:

~ Centennial Brook site #10 would reach a chloride level as high as 584 mg/L and didn't go below 368 mg/L

~ Engelsby Brook site #10 would reach a chloride level as high as 404 mg/L and didn't get below 228 mg/L

~ Indian Brook site #10 would reach a chloride level as high as 238 mg/L and went down to 116 mg/L

~ Indian Brook site #20 would reach a chloride level as high as 132 mg/L and went down to 28.6 mg/L

~ Milton Brook Site #10 would reach a chloride level of 37.2 mg/L with a low of 31.6 mg/L

~ Monroe Brook Site #10 would reach a chloride level of 179 mg/L with a low of 88.1 mg/L

~ Monroe Brook Site #20 would reach a chloride level of 93.6 mg/L with a low of 35.7 mg/L

~ Morehouse Brook Site # 10 would reach a chloride level of 130 mg/L with a low of 54 mg/L

~ Muddy Brook Site #10 would reach a chloride level of 129 mg/L with a low of 75.9 mg/L

~ Muddy Brook Site #20 would reach a chloride level of 145 mg/L with a low of 67.3 mg/L

~ Muddy Brook Site #30 would reach a chloride level of 31.2 mg/L with a low of 23.4 mg/L

~ Pottash Brook Site #10 would reach a chloride level as high as 440 mg/L with a low of 324 mg/L

~ Pottash Brook Site # 20 would reach a chloride level as high as 444 mg/L with a low of 266 mg/L

~ Pottash Brook Site #30 would reach a chloride level as high as 354 mg/L with a low of 294 mg/L

Reviewing the criteria for impaction, any person with hypertension would not be able to drink the water from these streams.

All of the sampled streams have chloride levels high enough to shift species compositions of algae and macroinvertebrates to those that are "salt tolerant".

Five of the sampled sites have chloride levels high enough to impact native trout populations.

Six of the sampled sites are impacted by chloride.

There are many Best Managements Practices that will reduce the amounts of sodium-chloride entering our water-ways.

For more information, please email: info@winooskinrcd.org