The data consists of the responses (survival, growth, and/or reproduction) of test organisms were determined in six concentrations of toxicants in 7-day toxicity tests or in four different feeding rates in 7-day feeding experiments. Specifically we evaluated the sensitivity of 2 mussel species (Villosa constricta and Lampsilis siliquoidea) and P. promelas and C. dubia using effluents in 7-d exposures. We then refined the method by determining the best feeding rate of algal mixture for 1-, 2-, and 3-wk-old L. siliquoidea in a 7-d feeding experiment, and using derived optimal feeding rates to assess the sensitivity of the 3 ages of juveniles in a 7-d NaCl test. Finally, we conducted an interlaboratory study among 13 laboratories to evaluate the performance of a 7-d NaCl test with L. siliquoidea.