The need for simple, fast and inexpensive tests to study metal pollution in the marine environment has become more pressing as utilization of coastal waters increases. To address this concern, the influence of four metals, cupric sulfate, lead nitrate, zinc sulfate and nickel sulfate, on emergence and hatching of the brine shrimp, Artemia, has been assessed. Occurrence of these easily recognized developmental milestones provides a convenient method to assay metal effects on development. Copper and lead were about equally toxic, reducing the rate and extent of Artemia development at or below concentrations of 0.1 microM. Zinc was somewhat less toxic than copper and lead, while nickel was the least toxic. Emerging Artemia are much more sensitive to metals than are larvae and adults. Furthermore, in contrast to results obtained with larvae and adults, the toxicity of lead is high when prelarval stages are considered. It is apparent from the findings that use of early stages of Artemia is an alternative to the examination of slower growing animals for the study of metal pollution in coastal marine waters.