The U.S. Environmental Protection Agency is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment of contaminants at Superfund sites. Benchmarks for invertebrates Were developed from existing literature. Insufficient information for Ba, Be, Mn, and Sb to generate Eco-SSLs necessitated standardized toxicity testing to fill the data gaps. We used the Enchytraeid Reproduction Test (ERT) with Enchytraeus crypticus in this study. This test was selected on the bases of its ability to measure chemical toxicity to ecologically relevant test species during chronic assay, and its inclusion of at least one reproductive component among the measurement endpoints. Tests were conducted in Sassafras sandy loam soil, which supports relatively high bioavailability of metals. Aging/weathering procedures for amended treatment soil were incorporated into the study to better reflect the "real world" exposure conditions. The toxicity order based on juvenile production was Be> Mn> Sb> Ba with EC20 values of 45, 116, 194, and 585 mg kg-1, respectively. These results show that ERT is a robust and sensitive assay for toxicity assessments and is appropriate for the Eco-SSL development.