FINAL PROJECT: Abstract and Reader's Reponse > Road Salt: A Literature Review of the Environmental and Ecological Impacts
N -- very good imagining of the difficult reader and excellent response.
To be clear, make sure that in your paper, you support the claims about human health and protection with some numbers. You can also estimate some of the effect -- with numbers and process -- about salt and aquatic health. All living beings are sensitive to salinity: reminding this reader early on that human beings are also sensitive to salinity and other salt concentrations, through the many homeostasis reactions that rely on electrolyte balance. Then, you can address this reader. :)
To be clear, make sure that in your paper, you support the claims about human health and protection with some numbers. You can also estimate some of the effect -- with numbers and process -- about salt and aquatic health. All living beings are sensitive to salinity: reminding this reader early on that human beings are also sensitive to salinity and other salt concentrations, through the many homeostasis reactions that rely on electrolyte balance. Then, you can address this reader. :)
May 7, 2015 |
Marybeth Shea
Marybeth Shea
Road salt, or NaCl, is our most common and popular chemical dicer in use today due to the salt’s low cost and a low effective temperature. Chemical deicing of roadways using road salt helps save lives by creating safer driving conditions in the snow and ice common to the winter months of much of the northern hemisphere. Storm water and spring melt water runoff mobilizes the road salt, which allows the salt to be transported into the environment surrounding our roadways, causing contamination of our freshwater. Research has found that, in areas where snow and ice are common in the winter, chloride concentrations due to road salt is elevated during the winter and spring months to levels far above the EPA recommended level of 230 mg/L. Increases in salinization and chloride concentrations of freshwater due to road salt have been linked with decreases in reproduction rates and lifespan of certain aquatic organisms and increases in microbial and algal growth that are associated with ecosystem damage. Increases in impermeable land coverage, increases in weathering of aquifer rock, and higher rates of mobilization of trace elements and heavy metals have also been found to be correlated with increased salinization and chloride concentrations due to road salt. Increases in chloride concentration was once thought to be only a local and short-term problem, but current research indicates that road salt can effect a much broader area and remain in the environment for long enough to increase annual chloride concentrations of freshwater.
Reader Profile:
Christian Herrmann - CEO of Morton Salt, Inc.
Reader Response:
Correlation does not prove causation. Though the evidence does point to road salt causing these environmental impacts, we cannot be sure that the road salt is at fault here, and not other factors. Even if the road salt was causing these impacts, the salt is used to save human lives. Alternative deicers are expensive and the cost of a human life is immeasurable.
Response to Reader:
It is correct that correlation does not prove causation, therefor it can not be said that road salt is responsible for these effects, and merely could be coincidence. What we do know is how salt reacts in water. Based on our understanding of chemistry, we know that salt breaks down into its ions, Na+ and Cl-, when mixed with water. When releasing free Na+ and Cl- ions, the ionic concentrations in the water will increase. That is something we know as fact. While these concentration increases may not be causing the negative impacts we see, based on ecological research on chlorides impact on organisms and chemical research on chlorides impact on the environmental chemistry, it is improbable that the road salt is not causing some negative effects.
Saving human lives is a top priority; there is no question about that. Alternative deicers may be more expensive currently, but the alternatives still need further research, which could inevitably lead to the production or discovery of an affordable alternative deicer. The cost to repair the environmental destruction due to the effects of road salt use could be significantly higher than the cost to use an alternative deicer, especially if the issue is not addressed over long time scales.
Salt use should not entirely cease, but rather environmental conditions should be monitored and road salt use should be adjusted to keep the environment safe.