Compliance Measures for Managing Chloride-Based Deicers

Focus Area

Water Quality/Wetlands


Natural Resources






2-3 years

Research Idea Scope

Chloride-based deicers continue to be the primary deicing chemical of choice due to the huge cost differential with non-chloride deicers. Essentially there are no salt alternatives that are comparable in terms of low cost and effective performance. However, there has been a trend where more and more water bodies are being listed as water quality impaired in the northern snowbelt states due to chloride levels exceeding the EPA’s recommended water quality standard for chloride established in 1988. Once listed as impaired, Total Maximum Daily Load (TMDL) studies are conducted and Waste Load Allocations (WLAs) are assigned to permitted entities such as DOTs. The TMDLs and WLAs are based solely on numeric water quality criteria and do not take into account actual field toxicity, winter climate variables, or public safety. Developing more practical performance standards could prevent unnecessary expenditures for chloride mitigation. Where chloride toxicity is identified as a problem then public agencies and others should consider implementation of appropriate practices to reduce excessive salt application. This could include training of applicators, certification, proper equipment, and maintenance. Although a recent (2013) “NCHRP Synthesis 449” report pertains to chloride management by DOTs, “Strategies to Mitigate the Impacts of Chloride Roadway Deicers…,” no reports were found that addressed the specific policy and compliance concerns targeted by this proposed study. Anticipated tasks for the project include: • Conduct a literature survey, which includes important background information such as EPA’s development of the water quality criteria for chloride, and the socio-economic and environmental pros and cons of DOTs using non-chloride deicing alternatives. • Develop guidelines and policy options for DOTs when negotiating TMDL compliance. • Identify water bodies for water quality sampling where the toxicological effects of chlorides could be isolated and measured.

Urgency and Payoff

This is of particular importance given the recent development of chloride TMDLs and the application of their respective chloride-reduction requirements, which can have unintended consequences and lead to the mismanagement of highway funds. This scenario occurred when the NH DOT built an additional travel lane along I-93, but the EPA prohibited its use due to the WLA prescribed by the Chloride TMDL Report. This study will serve to support better government decision-making by preventing indeterminate water quality requirements from blocking the construction of highway projects designed to enhance safety and otherwise serve public needs. In short, the study will help keep DOTs from having to choose between permit compliance and highway safety.

Suggested By

Henry L. Barbaro Stormwater Program Supervisor MassDOT, Highway Division 10 Park Plaza, Room 4260 Boston, MA 02116 (857) 368-8788

[email protected]