Abstract
Salinity (sodium chloride [NaCl]) is a prevalent and persistent contaminant that negatively affects freshwater ecosystems. Although most studies focus on effects of salinity from road salts (primarily NaCl), high-salinity wastewaters from energy extraction (wastewaters) could be more harmful because they contain NaCl and other toxic components. Many amphibians are sensitive to salinity, and their eggs are thought to be the most sensitive life-history stage. However, there are few investigations with salinity that include eggs and larvae sequentially in long-term exposures. We investigated the relative effects of wastewaters from a large energy reserve, the Williston Basin (USA), and NaCl on northern leopard (Rana pipiens) and boreal chorus (Pseudacris maculata) frogs. We exposed eggs and tracked responses through larval stages (for 24 days). Wastewaters and NaCl caused similar reductions in hatching and larval survival, growth, development, and activity, while also increasing deformities. Chorus frog eggs and larvae were more sensitive to salinity than leopard frogs, suggesting species-specific responses. Contrary to previous studies, eggs of both species were less sensitive to salinity than larvae. Our ecologically relevant exposures suggest that accumulating effects can reduce survival relative to starting experiments with unexposed larvae. Alternatively, egg casings of some species may provide some protection against salinity. Notably, effects of wastewaters on amphibians were predominantly due to NaCl rather than other components. Therefore, findings from studies with other sources of increased salinity (e.g., road salts) could guide management of wastewater-contaminated ecosystems, and vice versa, to mitigate effects of salinization. Environ Toxicol Chem 2021;40:3137–3147.
| Original language | English |
|---|---|
| Pages (from-to) | 3137-3147 |
| Number of pages | 11 |
| Journal | Environmental Toxicology and Chemistry |
| Volume | 40 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 2021 |
Funding
Protocols for animal collection, animal housing, and experiments were approved by the University of Montana Institutional Animal Care and Use Committee (Animal Use Proposal 024-18BHWB-050818 and 003-18BHWB-020618). We collected larvae under US Fish and Wildlife special use permit 61530-18-003; Montana Fish, Wildlife & Parks scientific collection permit 2019-100-W; and Wyoming Game and Fish Department 2019, Chapter 33 permit 350. The present study was supported by the University of Montana, the US Geological Survey (RWO #103), and the Nelson Schwab Family Foundation. For assistance in the field, we thank G. Renteria, C. Hurst, and D. Rose. Many thanks to E. Kenison for feedback on analyses and interpretation. We are grateful to K. Smalling, E. Crespi, L. Eby, and J. Millspaugh for early reviews of the manuscript. Protocols for animal collection, animal housing, and experiments were approved by the University of Montana Institutional Animal Care and Use Committee (Animal Use Proposal 024‐18BHWB‐050818 and 003‐18BHWB‐020618). We collected larvae under US Fish and Wildlife special use permit 61530‐18‐003; Montana Fish, Wildlife & Parks scientific collection permit 2019‐100‐W; and Wyoming Game and Fish Department 2019, Chapter 33 permit 350. The present study was supported by the University of Montana, the US Geological Survey (RWO #103), and the Nelson Schwab Family Foundation. For assistance in the field, we thank G. Renteria, C. Hurst, and D. Rose. Many thanks to E. Kenison for feedback on analyses and interpretation. We are grateful to K. Smalling, E. Crespi, L. Eby, and J. Millspaugh for early reviews of the manuscript.
| Funders | Funder number |
|---|---|
| Wyoming Fish and Game Department | |
| RWO #103 | |
Keywords
- Anthropogenic disturbances
- Contaminants
- Frog
- Prairie Pothole Region
- Road salts
- Salinization
