Using an inter-lab study to revise methods for conduction 10- to 42-d water or sediment toxicity tests with Hyalella azteca

Studies have been conducted to refine USEPA, ASTM, and Environment Canada standard methods for conducting 42-d reproduction tests with H. azteca in water or in sediment. Modifications to the H. azteca method include better defined ionic composition requirements for exposure water (i.e., >15 mg/L of chloride and >0.02 mg/L of bromide) and improved survival, growth and reproduction with alternate diets provided as increased rations over time in water-only or whole-sediment toxicity tests. A total of 24 laboratories volunteered to participate in an inter-laboratory study evaluating the performance of H. azteca in 42-d studies in control sand or control sediment using the refined methods. Improved growth and reproduction of H. azteca was [...]