You are here:
Acute Toxicity of Major Geochemical Ions to Fathead Minnows (Pimephales promelas)
Citation:
Erickson, R., Dave Mount, T. Highland, J. Hockett, D. Hoff, C. Jenson, T. Norberg-King, AND B. Forsman. Acute Toxicity of Major Geochemical Ions to Fathead Minnows (Pimephales promelas). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, , n/a - n/a, (2022). https://doi.org/10.1002/etc.5390
Impact/Purpose:
Anthropogenic increases of major geochemical (Ca, Mg, Na, K, Cl, SO4, HCO3/CO3) ions in aquatic systems are of widespread concern. Current regulatory efforts generally address just one (Cl) or two (Cl, SO4) of the anions based on single salt toxicity tests, usually with the Na salts, but available evidence indicates that major ion toxicity entails a complex mixture with multiple interactions and mechanisms of action. This paper describes extensive testing to more fully describe the acute toxicity of major ions to juvenile fathead minnows, identifying these various interactions and mechanisms and providing models for predicting the toxicity of a broad range of mixture composition. This should be of benefit to future regulatory efforts regarding major ion risks to freshwater systems. Acute Toxicity of Major Geochemical Ions to Fathead Minnows (Pimephales promelas ). Part B: Modeling Ion Toxicity First published: 06 June 2022 https://doi.org/10.1002/etc.5389
Description:
This paper reports on the results of a series of experiments on the acute toxicity of major geochemical ions (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, HCO3-/CO32-) to fathead minnows (Pimephales promelas). Tests of individual major ion salts in various dilution waters demonstrated that the toxicities of Na, Mg, and K salts decrease as the overall ion content of the dilution water increases. For Na and Mg salts, this is attributable to Ca content as previously reported for Ceriodaphnia dubia. For K salts, the cause is unclear, but is not due to Na as reported for C. dubia. NaHCO3 was also found to be twice as toxic at an unregulated high test pH of 9.3, compared to when the pH was reduced to 8.4. Experiments with binary salt mixtures indicated the existence of multiple independent mechanisms of action. These include K-specific toxicity and Ca/Mg-specific toxicity previously reported for C. dubia, but also apparent toxicities related to SO4 and to high pH/alkalinity in CO3/HCO3-dominated exposures.. Previous work with C. dubia also suggested a general ion toxicity involving all ions that was correlated with osmolarity. For fathead minnow, similar correlations were observed, but multiple mechanisms were indicated. At higher Ca, this general toxicity could be attributable to osmotic effects, but at lower Ca, osmolarity may be more a covariate than a cause, with this general toxicity being related to a combined effect of ions other than via osmolarity.
URLs/Downloads:
DOI: Acute Toxicity of Major Geochemical Ions to Fathead Minnows (Pimephales promelas)
MAJORIONTOXFATHEADMINNOW_PARTA_ACCEPTEDCOMBINE.PDF (PDF, NA pp, 4620.299 KB, about PDF)
MAJORIONTOXFHMACUTE_PARTBFINAL_ACCEPTEDCOMBINE.PDF (PDF, NA pp, 2686.474 KB, about PDF)