A peer-reviewed study recently completed by two professors finds the current environmental guidelines for road salt may not be restrictive enough to protect water fleas and could “wipe out” the species which is a key foundation of the aquatic food chain.
Water fleas (or Daphnia) are an important part of the ecosystem because they play an integral role in water quality and are a source of food. “These water fleas are like little living lawnmowers in our lakes. They ‘graze’ the entire volume of lakes many times during the summer, passing what they’ve eaten up the food chain to fish,” explains Professor Emeritus Norman Yan, senior scholar in the Department of Biology.
The study, conducted at Yan’s lab in the Department of Biology in the Faculty of Science, suggests that lake and highway authorities consider adjusting road salt use protocols to protect aquatic life such as the water flea by taking the nutritional status of the lakes into account. In particular, the study highlights the importance revising of the Water Quality Guideline for chloride, particularly for lakes near winter-maintained roads on the Canadian Shield that tend to have very low nutrient levels.
Environment Canada declared road salt to be toxic, when excessively used, to the environment in 2001 finding “high releases of road salts were having an adverse effect on freshwater ecosystems, soil, vegetation and wildlife”.
This declaration lead to regulations to decrease the amount of salt entering watershed and the requirement for Salt Management Plans to minimize salt usage. (Here’s Halton’s Plan)
Winter road salt levels are an increasing concern for Ontario municipalities as climate change is causing more unpredictable winters.
The winter of 2013/14 was particularly difficult with numerous freeze/thaw cycles resulting in high road salt usage and a shortage of supplies.
Liability Issues – Too Much, Too Little, What’s Right?
Road salt is a balancing act between the environment, cost, and liability.
Municipalities are forced to balance two different competing legal liabilities.
A recent case, covered by ThePublicRecord in January, resulted in the County of Lambton being ordered to compensate a farmer $106,000 for damage caused by road salt blowing and draining from a public highway onto his property.
On the flip side, there is a legal requirement for municipalities to maintain roads in a safe driving condition during winter weather, and the fear – expressed in the shortage article linked above – of legal liability for failing to use enough salt to make roads safe.
Road salt is a growing matter of municipal concern, and one I’ll be keeping an eye on to see what develops – if anything – from this study and the court decision in Lambton County.