SREL Reprint #3667

Major ion toxicity to glochidia of common and imperiled freshwater mussel species

Robert B. Bringolf1,2, Brenna K. Raines1, Robert E. Ratajczak1, and David Lee Haskins1,2,3

1Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30605, USA
2Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30605, USA
3Savannah River Ecology Lab, University of Georgia, Aiken, SC 29802, USA

Abstract: Freshwater mussel taxa are severely imperiled and among the most sensitive to several contaminants, including chloride. Relatively little is known of the toxicity of major ions to glochidia (larvae), particularly for rare species, or the effects of hardness on major ion toxicity to glochidia. Therefore, the primary objectives of this work were to: (1) determine the acute toxicity of major ion salts to glochidia, (2) compare chloride sensitivity of glochidia from common and rare species, and (3) evaluate the relationship between water hardness and chloride toxicity to glochidia. We assessed 24 h EC50s for fatmucket (Lampsilis siliquoidea) glochidia exposed to NaCl, KCl, MgCl2, CaCl2, Na2SO4, MgSO4, CaSO4, and NaHCO3 in moderately hard water. We determined NaCl EC50s for four species and KCl EC50s for glochidia of three species. Toxicity of chloride was generally consistent among the various chloride salts except for KCl, which was more toxic than all others by 1–2 orders of magnitude. Our results suggest that commonly tested species may be generally representative of rare species. Water hardness ameliorated the toxicity of chloride for all species to varying degrees. Results of this work indicate that some existing water quality criteria that do not include mussel toxicity data may not be protective of freshwater mussels.

Keywords: chloride; hardness; Unionidae; sensitivity

SREL Reprint #3667

Bringolf, R. B., B. K. Raines, R. E. Ratajczak, and D. L. Haskins. 2022. Major ion toxicity to glochidia of common and imperiled freshwater mussel species. Diversity 14(2): 95.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).