Abstract
Field and laboratory studies have shown that mayflies (Ephemeroptera) tend to be relatively sensitive to elevated major ion concentrations, but little is known about how ionic composition influences these responses. The present study evaluated the acute toxicity of major ion salts to the mayfly Neocloeon triangulifer over a range of background water quality conditions. The mayfly was particularly sensitive to Na2SO4, with the median lethal concentration (LC50) of 1338 mg SO4/L being lower than LC50s reported for 7 other species at that hardness. Increasing hardness of the dilution water from 30 to 150 mg/L (as CaCO3) resulted in doubling of LC50s for sodium salts, and an approximately 1.5-fold increase in LC50 for MgSO4. Potassium salt toxicity was not strongly influenced by hardness, consistent with findings for other species. When hardness was held constant but the Ca to Mg ratio was manipulated, the ameliorative effect on Na2SO4 and NaCl did not appear as strong as when hardness was varied; but for MgSO4 the amelioration relative to Ca activity was similar between the 2 experiments. The toxicity of K salts to N. triangulifer was similar to Na salts on a millimolar basis, which contrasts with several other species for which K salts have been much more toxic. In addition, the toxicity of KCl to N. triangulifer was not notably affected by Na concentration, as has been shown for Ceriodaphnia dubia. Finally, plotting LC50s in terms of ion activity (Cl, SO4, Na, Mg, or K) over the range of Ca activities in dilution water resulted in significant positive relationships, with comparable slopes to those previously observed for C. dubia over the same range of Ca activities. Environ Toxicol Chem 2018;37:1330–1339.
Original language | English (US) |
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Pages (from-to) | 1330-1339 |
Number of pages | 10 |
Journal | Environmental Toxicology and Chemistry |
Volume | 37 |
Issue number | 5 |
DOIs | |
State | Published - May 2018 |
Bibliographical note
Funding Information:Acknowledgment—We thank R. Erickson, USEPA, Mid-Continent Ecology Division, for consulting on experimental design and analysis. D. Glazik (University of Illinois) assisted with toxicity testing. J. Jackson, Stroud Water Research Center, provided the unpublished Stroud Water Research Center data referred to throughout the text. The present study was funded by the Great Lakes Restoration Initiative by way of a Cooperative Ecosystem Studies Unit grant from the US Geological Survey, Columbia Environmental Research Center.
Funding Information:
We thank R. Erickson, USEPA, Mid-Continent Ecology Division, for consulting on experimental design and analysis. D. Glazik (University of Illinois) assisted with toxicity testing. J. Jackson, Stroud Water Research Center, provided the unpublished Stroud Water Research Center data referred to throughout the text. The present study was funded by the Great Lakes Restoration Initiative by way of a Cooperative Ecosystem Studies Unit grant from the US Geological Survey, Columbia Environmental Research Center.
Publisher Copyright:
© 2018 SETAC
Keywords
- Acute toxicity
- Major ion
- Mayfly
- Neocloeon triangulifer
- Salinity