Sediment-Water Chironomid Toxicity Test Using Spiked Water (OECD TG 219)
The Sediment-Water Chironomid Toxicity Test using spiked water according to OECD TG 219 is designed to evaluate the effects of substances on sediment-dwelling aquatic invertebrates, with a focus on Chironomus species (non-biting midges). These organisms are key components of freshwater benthic ecosystems and are widely used as indicators of sediment-associated toxicity.
In this study, the test substance is introduced into the overlying water rather than directly into the sediment, allowing it to partition naturally between the water and sediment phases. Larvae of Chironomus are then exposed under controlled laboratory conditions, typically for a duration of up to 28 days.
Endpoints assessed include larval survival, growth (e.g. dry weight), and adult emergence. These data are used to establish concentration–response relationships and to derive chronic toxicity endpoints such as the No Observed Effect Concentration (NOEC) and the Lowest Observed Effect Concentration (LOEC).
This test complements sediment-spiked studies by providing insight into the bioavailability and effects of substances entering aquatic systems via the water phase, thereby supporting a comprehensive environmental risk assessment of sediment-associated contaminants.
