TY - JOUR
T1 - Assessing the Relative Toxicity of Different Road Salts and Effect of Temperature on Salinity Toxicity
T2 - LCx Values versus No-Effect Concentration (NEC) Values
AU - Moulding, Benjamin J.G.
AU - Kon Kam King, Guillaume
AU - Shenton, Mark
AU - Bray, Jon P.
AU - Nichols, Susan J.
AU - Kefford, Ben J.
N1 - Funding Information:
We thank the Australian Alps National Parks Cooperative Management Program for funding, from which Shenton and Moulding received scholarships. Many thanks to the volunteers that helped with collections for these experiments, Callum Mckinnon, Kaylin de Lembracht, Brian Johnston and Hannah Moulding. Thanks are greatly due to Marie Laure Delignette-Muller for her valued suggestions of extra references in the peer review process. We thank the two peer reviewers and editors for their thoughtful comments. We thank the staff from NSW RMS and Perisher for supplying salt samples and salt application information. The research reported was conducted under a Scientific License (No. SL101713) from the NSW Parks and Wildlife Service.
Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2022/2
Y1 - 2022/2
N2 - Freshwater biota are at risk globally from increasing salinity, including increases from deicing salts in cold regions. A variety of metrics of toxicity are used when estimating the toxicity of substances and comparing the toxicity between substances. However, the implications of using different metrics are not widely appreciated. Using the mayfly Colobruscoides giganteus (Ephemeroptera: Colobruscoidea), we compare the toxicity of seven different salts where toxicity was estimated using two metrics: (1) the no-effect concentrations (NEC) and (2) the lethal concentrations for 10, 25 and 50% of the test populations (LCx). The LCx values were estimated using two different models, the classic log-logistic model and the newer toxicokinetic–toxicodynamic (TKTD) model. The NEC and both types of LCx values were estimated using Bayesian statistics. We also compared the toxicity of two salts (NaCl and CaCl2) for C. giganteus at water temperatures of 4 °C, 7 °C and 15 °C using the same metrics of toxicity. Our motivation for using a mayfly to assess salinity toxicity was because mayflies are generally salt sensitive, are ecologically important and are common in Australian (sub-)alpine streams. The temperature ranges were chosen to mimic winter, spring and summer water temperatures for Australian (sub-)alpine streams. Considering 144-h classical LCx values, we found toxicity differed between various salts, i.e., the lowest 144-h LC50 (8 mS/cm) for a salt used by a ski resort was half that of the highest 144-h LC50 from artificial marine salts and CaCl2 applied to roads (16 mS/cm). The analytical grade NaCl (as shown by 144-h LC50 value at 7 °C) was substantially more toxic (7.3 mS/cm) compared to analytical grade CaCl2 (12.5 mS/cm). Yet for NEC values, there were comparably fewer differences in toxicity between salts and none between the same salts at different temperatures. We conclude that LCx values are better suited to compare the difference in toxicity between substances or between the same substance at different test temperatures, while NEC values are better suited to estimating concentrations of substances that have no effect to the test species and endpoint measured under laboratory conditions.
AB - Freshwater biota are at risk globally from increasing salinity, including increases from deicing salts in cold regions. A variety of metrics of toxicity are used when estimating the toxicity of substances and comparing the toxicity between substances. However, the implications of using different metrics are not widely appreciated. Using the mayfly Colobruscoides giganteus (Ephemeroptera: Colobruscoidea), we compare the toxicity of seven different salts where toxicity was estimated using two metrics: (1) the no-effect concentrations (NEC) and (2) the lethal concentrations for 10, 25 and 50% of the test populations (LCx). The LCx values were estimated using two different models, the classic log-logistic model and the newer toxicokinetic–toxicodynamic (TKTD) model. The NEC and both types of LCx values were estimated using Bayesian statistics. We also compared the toxicity of two salts (NaCl and CaCl2) for C. giganteus at water temperatures of 4 °C, 7 °C and 15 °C using the same metrics of toxicity. Our motivation for using a mayfly to assess salinity toxicity was because mayflies are generally salt sensitive, are ecologically important and are common in Australian (sub-)alpine streams. The temperature ranges were chosen to mimic winter, spring and summer water temperatures for Australian (sub-)alpine streams. Considering 144-h classical LCx values, we found toxicity differed between various salts, i.e., the lowest 144-h LC50 (8 mS/cm) for a salt used by a ski resort was half that of the highest 144-h LC50 from artificial marine salts and CaCl2 applied to roads (16 mS/cm). The analytical grade NaCl (as shown by 144-h LC50 value at 7 °C) was substantially more toxic (7.3 mS/cm) compared to analytical grade CaCl2 (12.5 mS/cm). Yet for NEC values, there were comparably fewer differences in toxicity between salts and none between the same salts at different temperatures. We conclude that LCx values are better suited to compare the difference in toxicity between substances or between the same substance at different test temperatures, while NEC values are better suited to estimating concentrations of substances that have no effect to the test species and endpoint measured under laboratory conditions.
UR - http://www.scopus.com/inward/record.url?scp=85123834572&partnerID=8YFLogxK
U2 - 10.1007/s00244-021-00908-1
DO - 10.1007/s00244-021-00908-1
M3 - Article
C2 - 35091822
AN - SCOPUS:85123834572
SN - 0090-4341
VL - 82
SP - 281
EP - 293
JO - Archives of Environmental Contamination and Toxicology
JF - Archives of Environmental Contamination and Toxicology
IS - 2
ER -
