Development and application of a sediment toxicity test using the benthic cladoceran Chydorus sphaericus

This study reports on the development and application of a whole sediment toxicity test using a benthic cladoceran Chydorus sphaericus, as an alternative for the use of pelagic daphnids. A C. sphaericus laboratory culture was started and its performance under control conditions was optimised. The test was firstly validated by determining dose–response relationships for aqueous cadmium and copper and ammonia, showing a sensitivity of C. sphaericus (96 h LC50 values of 594 µg Cd/L, 191 µg Cu/L and 46 mg ammonia/L at pH 8) similar to that of daphnids. Next, sediment was introduced into the test system and a series of contaminated sediments from polluted locations were tested. A significant negative correlation between survival and toxicant concentrations was observed. It is concluded that the test developed in the present study using the benthic cladoceran C. sphaericus is suitable for routine laboratory sediment toxicity testing. A test was developed for assaying sediment toxicity using a commonly occurring small-bodied cladoceran. [KEYWORDS: Chydorus ; Daphnia ; Laboratory culture ; Sediment toxicity test]