Acute toxicity of seven de-icing salts on four zooplankton species– is there an “eco-friendly” alternative?

Abstract

While de-icing salts improve safety on roads and sidewalks during winter, they have a negative impact on the environment. This has spurred the search for more environmentally-friendly alternatives. The present study tests the impact of NaCl and six other de-icing salts (pure CaCl2, CaCl2+NaCl, “eco-label” CaCl2, MgCl2, solid and liquid CH3COOK), promoted as more eco-friendly alternatives to NaCl, on four zooplankton species from biotests: Ceriodaphnia dubia (Ceriodaphtokit), Daphnia magna (Daphtoxkit), Brachionus calyciflorus (Rotoxkit) and Thamnocephalus platyurus (Thamnotoxkit). 24-h EC50 evaluation showed that only solid CH3COOK was less toxic for all tested species than NaCl. The other tested de-icing salts had similar or even higher toxicity, with CaCl2, MgCl2 and liquid CH3COOK being significantly more toxic for all species than NaCl. Of the tested species, Thamnocephalus platyurus demonstrated toxicity response at significantly lower concentration of all used de-icing salts, while Daphnia magna had significantly the highest concentrations of toxicity response. Our findings demonstrate that these alternatives are not less toxic in this regard than the commonly-used NaCl and underline the need to verify the accuracy of the term “eco-friendly” on the labels of these products.