Effect of Acclimation Period on the Relationship of Acute Copper Toxicity to Water Hardness for Fathead Minnows

Abstract

The acute (96-h) toxicity of copper sulfate to fathead minnows was tested in a 2 ϫ 2 factorial experiment, with factors being low (ca. 1 meq/L) and high (ca. 4 meq/L) water hardness during an acclimation period and low and high hardness during the exposure period. Acclimation hardness was found to have no significant effects on copper lethality, except that the 24-h LC50 at high exposure hardness was 44% higher for fish subject to low acclimation hardness than fish subject to high acclimation hardness. In contrast, exposure hardness was found to have major effects, with LC50s being two to three times greater at high exposure hardness than at low, regardless of the acclimation hardness. These results suggest that the extent of the acclimation period is not a general, severely confounding factor for previous reports of the effects of hardness on copper toxicity to fish, although it may assume some importance for some species and test conditions. Keywords-CopperToxicity Fathead minnow Hardness AcclimationEnviron. Toxicol. Chem. 16, 1997 R.J. Erickson et al.

Evaluation of water‐effect ratio methodology for establishing site‐specific water quality criteria

“…It is less clear what effect occurs when fish are acclimated in soft water and tested in hard water. In testing performed with fathead minnows, Erickson et al [7] saw little to no influence of acclimation to total hardness on Cu toxicity. However, in our testing with rainbow trout, we observed that fish acclimated to soft water and tested in hard water are significantly more tolerant of Cu (higher LC50s) than fish acclimated and tested in hard water, possibly as a result of physiological adaptations to low Ca water (e.g., increased number of chloride cells).…”

“…Erickson et al [7] also investigated the influence of acclimation on total hardness in acute Cu flow‐through toxicity tests performed with fathead minnows ( Pi‐mephales promelas ). In their experiments, fish were acclimated for 12 d to a total hardness of either 47 or 215 mg/L and tested at a total hardness of 47 and 215 mg/L [7]. Total hardness was modified in their experiments by adding calcium chloride; hence, the high hardness treatment was dominated by Ca hardness and not Mg hardness.…”

Variability of the protective effect of sodium on the acute toxicity of copper to freshwater cladocerans

“…Although these Na concentrations are higher than in most “typical” natural waters (e.g., the 95th percentile of Na in surface waters of Europe is ∼2.5 mM; http://www.gsf.fi/publ/foregsatlas/maps/Water/w_icpoes_na_edit.pdf), they were needed to determine the protective effects of Na on Cu toxicity for different species in a quantitative manner. Organisms were not acclimated to the Na concentrations of the tests waters before testing, but Erickson et al [2] have suggested that prior acclimation to test solution chemistry is not a general, severely confounding factor in bioavailability studies with Cu.…”

Effect of Culture Water Hardness on the Sensitivity of Ceriodaphnia Dubia to Copper Toxicity

“…Laurén and McDonald [3] reported that organisms such as rainbow trout (Onchorynchus mykiss) should be acclimated to test waters for at least two weeks to minimize any undue bias in ion regulation resulting from changes in water chemistry between culture (holding) and test waters. However, this phenomenon was not observed with fathead minnows (Pimephales promelas) [5]. However, this phenomenon was not observed with fathead minnows (Pimephales promelas) [5].…”

“…22, 20031271 (or acclimation) water can also affect an organism's sensitivity [9,10] and may account for some of the observed variation in organism response to metal toxicity [3]. In studies with fathead minnows, Erickson et al [5] reported no significant differences in 96-h LC50s due to acclimation conditions, although LC50s were slightly higher for organisms acclimated in the higherhardness water (215 vs 47 mg/L hardness as CaCO 3 ). This was consistent for both exposure water hardnesses tested.…”