Toxicity of copper-spiked sediments to Tubifex tubifex (Oligochaeta, Tubificidae): Comparison of the 28-day reproductive bioassay with an early-life-stage bioassay

Two sediment bioassay methods using Tubifex tubifex (Muller, 1774) as the t est species were compared. The first was an adult reproduction test, the se cond an early-life-stage survival test. The duration of both bioassays is 2 8 d and the amount of work required was similar; they may be useful alterna tives to each other in different circumstances (e.g., the early life stage bioassay could be carried out with smaller volumes of sediment). The two bi oassays were performed simultaneously on copper-spiked sediments. Sediments from two freshwater and two terrestrial sites were used: five separate, no nsimultaneous experiments were performed, one for each sediment or soil and a further experiment with soil with a food supplement. In the adult bioass ay, there were large differences in the production of cocoons, eggs, and yo ung among the control treatments of the five experiments. There were also m ajor differences in the NOEC (no-observed-effect concentration) and LOEC (l owest-observed-effect concentration) for copper between the tested substrat es. The early life stage bioassay appears to be less sensitive to copper to xicity than the adult reproductive bioassay since NOECs and LOECs are highe r for early survival than for the most sensitive endpoints of the adult bio assay in three experiments out of five.