Toxicity of deicing salt components to early amphibian life stages

Abstract

Chemical contamination is a primary factor contributing to worldwide amphibian declines. Road salt is a major pollutant producing elevated chloride concentrations in freshwater systems. Additionally, ferrocyanide anti-caking agents are released from road salt and effects on the environment are poorly understood. Amphibians exhibit low tolerance to salt. Our purpose is to investigate chronic, sub-lethal NaCl exposure on developmental amphibian stages and determine acute toxicity of cyanide. Chronic toxicity experiments at environmentally significant salt concentrations were conducted on larvae of three species and embryos of five species in the laboratory. Species tested were spotted salamanders, American toads, spring peepers, green frogs and wood frogs. Cyanide acute toxicity experiments were performed on the five species. Chronic salt exposure reduced hatching, increased mortality, and induced developmental and behavioural anomalies. Median lethal concentration values were calculated from cyanide acute toxicity experiments. Results indicate that the chronic effects can inflict detrimental consequences to amphibian populations.