Examining Ecological Impacts of Road Salts vs. Beet Brine

The Problem

Winter road safety often depends on the use of salt. But when snow melts, that salt washes into waterways. Rising salinity in streams, especially in the Midwest and Northeast, has raised concerns about its effects on aquatic ecosystems. Beet brine, a mix of salt and beet molasses, is marketed as an eco-friendly alternative because it reduces salt use. However, beet brine also adds nutrients like nitrogen and phosphorus to runoff. Understanding how these products affect microbial processes, such as leaf litter decomposition, is critical for balancing road safety with water quality.

The Work

Water quality researcher Shannon Speir, Assistant Professor of Crop, Soil and Environmental Sciences with the Dale Bumpers College of Agricultural, Food and Life Sciences and the Arkansas Agricultural Experiment Station, and graduate student Caroline Anscombe partnered with researchers at the University of Notre Dame to study the effects of road salt and beet brine on leaf litter decomposition. Using recirculating aquatic mesocosms, which are artificial water enclosures that mimic stream conditions, they exposed different types of leaves to low and high concentrations of both deicers. The team measured decomposition rates and microbial colonization over two weeks to see how these treatments influenced stream processes.

The Results

Contrary to initial expectations, the results suggested that decomposition rates were not significantly affected by any of the deicer treatments over the two-week duration. Beet brine decreased decomposition rates for maple leaves more than traditional road salt in the first seven days but did not significantly impact overall leaf litter decomposition. Microbial colonization of oak leaves also increased with each of the deicing treatments. Additionally, the study did not show differences between low and high salt treatments in any of the response metrics.

The Value

The study provides an improved understanding of the environmental impacts of both traditional and “eco-friendly” deicers to inform winter road management decisions that protect freshwaters from salinization. Anscombe said future studies may be needed to evaluate the effects of repeated deicer treatments and the residence time, or how long these products are staying in the environment, to determine the potential longer-term impacts of beet brine products on freshwater ecosystems. For now, Speir emphasizes the importance of “Smart Salt” practices, which call for using brine solutions only as needed, to reduce unnecessary salt runoff and protect water quality while maintaining road safety.