title: Effects of six chemical deicers on larval wood frogs (Rana sylvatica).
abstract: Widespread and intensive application of road deicers, primarily road salt (NaCl), in North America threatens water quality and the health of freshwater ecosystems. Intensive use of NaCl can be harmful to sensitive members of freshwater ecosystems such as amphibians. Detection of negative effects of NaCl application has prompted the search for alternative chemical deicers with lower environmental impacts. We conducted a series of 96-h acute toxicity tests to determine the negative sensitivity of larval wood frogs (Rana [Lithobates] sylvatica) to six deicing chemicals: urea (CH(4) N(2) O), sodium chloride (NaCl), magnesium chloride (MgCl(2) ), potassium acetate (CH(3) COOK), calcium chloride (CaCl(2) ), and calcium magnesium acetate (C(8) H(12) CaMgO(8) ). Acetates are sometimes touted as environmentally friendly alternatives to NaCl but have not been examined in enough detail to warrant this designation. When exposed to a range of environmentally realistic concentrations of these chemicals, larvae were least sensitive (i.e., had the lowest mortality rate) to CH(4) N(2) O, NaCl, and MgCl(2) and most sensitive to acetates (C(8) H(12) CaMgO(8) , CH(3) COOK) and CaCl(2) . Our observed median lethal concentration estimates (LC50(96-h) ) for NaCl were over two times higher than values presented in previous studies, which suggests variability in tolerance among R. sylvatica populations. The deicers varied greatly in their toxicity, and further research is warranted to examine the differential effects of this suite of deicers on other species.
authors.affiliation: Michigan Technological University, Houghton, Michigan, USA. mlharles@mtu.edu
authors.forename: Meagan L
authors.initials: ML
authors.lastname: Harless
authors.forename: Casey J
authors.initials: CJ
authors.lastname: Huckins
authors.forename: Jacqualine B
authors.initials: JB
authors.lastname: Grant
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Pypker
mesh_terms: D000085:Acetates / Q000633:toxicity*; D000818:Animals; D002122:Calcium Chloride / Q000633:toxicity; D017610:Calcium Compounds / Q000633:toxicity; D002712:Chlorides / Q000633:toxicity*; D017753:Ecosystem; D005618:Fresh Water / Q000737:chemistry; D007814:Larva / Q000187:drug effects; D015636:Magnesium Chloride / Q000633:toxicity; D011898:Ranidae / Q000502:physiology*; D054712:Salinity; D012965:Sodium Chloride / Q000633:toxicity; D014186:Transportation; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000085:Acetates; D017610:Calcium Compounds; D002712:Chlorides; D014874:Water Pollutants, Chemical; D015636:Magnesium Chloride; D012965:Sodium Chloride; D002122:Calcium Chloride; C120662:calcium acetate