Road Salt Impacts Freshwater Zooplankton at Concentrations below Current Water Quality Guidelines

Widespread use of NaCl for road deicing has caused increased chloride concentrations in lakes near urban centers and areas of high road density. Chloride can be toxic, and water quality guidelines have been created to regulate it and protect aquatic life. However, these guidelines may not adequately...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 2020-08, Vol.54 (15), p.9398-9407
Main Authors: Arnott, Shelley E, Celis-Salgado, Martha P, Valleau, Robin E, DeSellas, Anna M, Paterson, Andrew M, Yan, Norman D, Smol, John P, Rusak, James A
Format: Article
Language:English
Subjects:
Aquatic organisms
Canadian Shield
Chloride
Chlorides
Contaminants in Aquatic and Terrestrial Environments
Daphnia
Deicers
Guidelines
Lake sediments
Lakes
Plankton
Precambrian
Road salt
Roads
Roads & highways
Salts
Sediments
Sodium chloride
Urban areas
Urban environments
Water quality
Water softening
Zooplankton
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Widespread use of NaCl for road deicing has caused increased chloride concentrations in lakes near urban centers and areas of high road density. Chloride can be toxic, and water quality guidelines have been created to regulate it and protect aquatic life. However, these guidelines may not adequately protect organisms in low-nutrient, soft water lakes such as those underlain by the Precambrian Shield. We tested this hypothesis by conducting laboratory experiments on six Daphnia species using a soft water culture medium. We also examined temporal changes in cladoceran assemblages in the sediments of two small lakes on the Canadian Shield: one near a highway and the other >3 km from roads where salt is applied in the winter. Our results showed that Daphnia were sensitive to low chloride concentrations with decreased reproduction and increased mortality occurring between 5 and 40 mg Cl–/L. Analysis of cladoceran remains in lake sediments revealed changes in assemblage composition that coincided with the initial application of road salt in this region. In contrast, there were no changes detected in the remote lake. We found that 22.7% of recreational lakes in Ontario have chloride concentrations between 5 and 40 mg/L suggesting that cladoceran zooplankton in these lakes may already be experiencing negative effects of chloride.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.0c02396