Reducing Chloride Discharges to Surface Water and Groundwater: A Menu of Options for Policymakers

Abstract

Greater environmental protections and increased public safety are often believed to be synonymous, or at least to go hand-in-hand. Sometimes, however, those two goals are arguably in tension; for example, when the excess application of salt for winter deicing, in combination with other chloride sources, causes elevated chloride concentrations in waterways. Sodium chloride, commonly known as salt, has often played a critical role in human culture, trade, religion, economics, public safety, and even warfare. But it has a complicated legacy that includes potentially serious adverse consequences for human health and the environment, including deteriorated water quality, toxicity to aquatic and benthic organisms, adverse effects on vegetation, and impacts to drinking water supplies. Moreover, environmental chloride concentrations are on the rise, having approximately doubled over the past two decades. Hundreds of scientific studies have examined potential risks to human health and the environment associated with excess chlorides in the environment, especially those sourced from deicing operations. Yet little, if any, of that work has been directed toward developing legal and policy strategies to address the chloride issue.

This interdisciplinary paper examines the underlying causes of unsustainable chloride pollution from a scientific and engineering perspective, and then proposes a menu of responsive legal and policy options. These options include incentivized self-governance at the community or individual levels; informational strategies to encourage optimal chloride use levels for deicing and in water softening applications; direct legal and regulatory mechanisms or mandated best practices issued pursuant to the Clean Water Act, state regulations, or municipal ordinances; use of chloride alternatives such as green infrastructure and substitute deicing substances; integrated watershed management; and direct economic measures. The paper does not suggest that all these options are appropriate in every context, nor does it rank them from most to least useful. Those decisions are left to affected stakeholders.

Keywords: Environmental Law, Water Law, Chloride, Water Policy

JEL Classification: K32