Acute toxicity of sodium chloride and potassium chloride to a unionid mussel (Lampsilis siliquoidea) in water exposures

Abstract

Freshwater mussels (order Unionoida) are one of the most imperiled groups of animals in the world. However, many ambient water quality criteria and other environmental guideline values do not include data for freshwater mussels, in part because mussel toxicity test methods are comparatively new and data may not have been available when criteria and guidelines were derived. The objectives of the present study were to evaluate the acute toxicity of sodium chloride (NaCl) and potassium chloride (KCl) to larvae (glochidia) and/or juveniles of a unionid mussel (fatmucket, Lampsilis siliquoidea) and to determine the potential influences of water hardness (50, 100, 200, and 300 mg/L as CaCO ) and other major ions (Ca, K, SO , or HCO ) on the acute toxicity of NaCl to the mussels. From the KCl test, the 50% effect concentration (EC50) for fatmucket glochidia was 30 mg K/L, similar to or slightly lower than the EC50s for juvenile fatmucket (37-46 mg K/L) tested previously in our laboratory. From the NaCl tests, the EC50s for glochidia increased from 441 to 1597 mg Cl/L and the EC50s for juvenile mussels increased from 911 to 3092 mg Cl/L with increasing water hardness from 50 to 300 mg/L. Increasing K from 0.4 to 1.9 mg/L, SO from 13 to 40 mg/L, or HCO from 44 to 200 mg/L in the 50 mg/L hardness water did not substantially change the NaCl EC50s for juvenile mussels, whereas increasing Ca from 9.9 to 42 mg/L increased the EC50s by a factor of 2. The overall results indicate that glochidia were equally or more sensitive to NaCl and KCl compared with juvenile mussels and that the increased water hardness ameliorated the acute toxicity of NaCl to glochidia and juveniles. These responses rank fatmucket among the most acutely sensitive freshwater organisms to NaCl and KCl. Environ Toxicol Chem 2018;37:3041-3049. © 2018 SETAC. This article is a US government work and, as such, is in thepublic domain in the United States of America.

Evaluation of chronic toxicity of sodium chloride or potassium chloride to a unionid mussel (Lampsilis siliquoidea) in water exposures using standard and refined toxicity testing methods

“…Methods for holding and feeding the female mussels at the Columbia Environmental Research Center (CERC; Columbia, MO) and methods for culturing juvenile mussels at Missouri State University (Springfield, MO) are described in the companion study regarding the acute toxicity of NaCl and KCl to juvenile fatmucket (Wang et al 2018b). Methods for holding and feeding the female mussels at the Columbia Environmental Research Center (CERC; Columbia, MO) and methods for culturing juvenile mussels at Missouri State University (Springfield, MO) are described in the companion study regarding the acute toxicity of NaCl and KCl to juvenile fatmucket (Wang et al 2018b).…”

“…The diluter system created and delivered 5 test concentrations with a 50% dilution series, plus control water, into 300-mL replicate glass beakers. To facilitate comparison to other published data and regulatory guidelines, the results from the present study are expressed as Cl (for NaCl) and K (for KCl) concentrations, but this should not be taken as an assertion that these are the only appropriate exposure metrics, especially for NaCl (Wang et al 2018b). The nominal concentrations of KCl (99.7% purity; Fisher Scientific) were 1.9 (control), 12,24,48,95,and 191 mg KCl/L (i.e.,1.0,6.3,13,25,50, and 100 mg K/L).…”

“…In addition, the survival of the 2-mo-old fatmucket in the KCl exposure was determined on test day 4 to evaluate the acute effect because the high sensitivity of larval and newly transformed (a few days old) fatmucket to KCl had been observed in previous studies (Wang et al 2017a(Wang et al , 2018b and there was a lack of acute KCl data for older juvenile mussels. A chronic 4-wk KCl toxicity test was conducted with juvenile fatmucket (starting age $70 d) in water exposures with and without sand under the same test conditions as the 2012 chronic NaCl test, except that water temperature was maintained at 23 AE 1 8C (rather than 20 8C) and only dry weight was measured for the growth endpoint (rather than length and dry wt).…”

“…The control mussels in the 2 exposures with and without sand had a similar increase in dry weight over the 4-wk exposure periods (2.3-fold of initial wt; Table 1). The acute 4-d toxicity data have been included in the discussion on acute sensitivity comparisons among different life stages of the same test species and among different species in the companion article (Wang et al 2018b). The details on the 4-d survival in each treatment and measured water quality characteristics are provided in Supplemental Data, Tables S3 and S4.…”

“…As one of 2 companion studies to evaluate the toxicity of NaCl and KCl to different life stages of mussels (Wang et al 2018b), the objectives of the present study were to 1) refine test conditions for improving mussel survival and growth in a longterm feeding study, 2) evaluate chronic toxicity of NaCl and KCl to fatmucket under traditional test conditions outlined in ASTM International (2017) and the refined test conditions, and 3) assess the influence of test duration, starting age of organisms, and presence of sand substrate on the sensitivity of juvenile fatmucket to NaCl in chronic exposures under refined test conditions. The present study primarily reports the mussel responses from the chronic toxicity tests; results of the feeding study are presented in Supplemental Data, Section S1.…”