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

Individual measurements of toxicity and water quality data used to calculate means reported in the associated publication. The objectives of the present study were to (1) refine test conditions for improving mussel survival and growth in a long-term feeding study, (2) evaluate chronic toxicity of NaCl and KCl to fatmucket under traditional test conditions outlined in ASTM (ASTM 2017) and the refined test conditions, and (3) assess the influences of test durations, starting ages of organisms, and the presence of sand substrate on the sensitivity of juvenile fatmucket to NaCl in chronic exposures under refined test conditions. Multiple tests were conducted to determine the chronic toxicity of sodium chloride (NaCl) or potassium chloride (KCl) to a unionid mussel (fatmucket, Lampsilis siliquoidea). Initially, a 4-week NaCl test and a 4-week KCl test were conducted starting with 2-month-old mussels following the ASTM standard method. A feeding study was conducted later to refine test conditions for a longer-term 12-week exposure, and 3 additional chronic NaCl tests were then conducted following the refined method to assess the influences of test durations (4 to 12 weeks) and age of organisms (starting age ~1 week to 2 months old) on mussel sensitivity to NaCl.