biostudies-literatureErickson RJIntramural EPA2078-2094https://www.ebi.ac.uk/biostudies/studies/S-EPMC9533472biostudies-literatureUnknown41(9)The results of a series of experiments on the acute toxicity of major geochemical ions (Na⁺ , K⁺ , Ca²⁺ , Mg²⁺ , Cl^- , SO₄ ^2- , HCO₃ ^- /CO₃ ^2- ) to fathead minnows (Pimephales promelas) are reported. 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 it is not due to Na as reported for C. dubia. In an unregulated test at high pH (9.3), NaHCO₃ was also found to be twice as toxic comparedEnvironmental toxicology and chemistryAcute Toxicity of Major Geochemical Ions to Fathead Minnows (Pimephales Promelas): Part A-Observed Relationships for Individual Salts and Salt Mixtures.PMC9533472EPA999999Norberg-King TJHockett JRForsman BHoff DJJenson CTHighland TLMount DRErickson RJfalseAcute Toxicity of Major Geochemical Ions to Fathead Minnows (Pimephales Promelas): Part A-Observed Relationships for Individual Salts and Salt Mixtures.The results of a series of experiments on the acute toxicity of major geochemical ions (Na⁺ , K⁺ , Ca²⁺ , Mg²⁺ , Cl^- , SO₄ ^2- , HCO₃ ^- /CO₃ ^2- ) to fathead minnows (Pimephales promelas) are reported. 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 it is not due to Na as reported for C. dubia. In an unregulated test at high pH (9.3), NaHCO₃ was also found to be twice as toxic compared2022-01-01T00:00:00Z2022 Sep2025-04-25T20:20:00.262Z2025-04-06T08:20:52.009ZS-EPMC95334723562201210.1002/etc.5390