Water-Sediment Myriophyllum spicatum Toxicity Test (OECD TG 239)
The Water-Sediment Myriophyllum spicatum Toxicity Test according to OECD TG 239 is designed to assess the effects of chemicals on aquatic vascular plants under more environmentally realistic conditions, where exposure occurs via both water and sediment. Myriophyllum spicatum (Eurasian watermilfoil) is a key primary producer in freshwater ecosystems and plays an important ecological role.
In this test, actively growing plant fragments are introduced into a test system containing both water and sediment spiked with the test substance. Plants are exposed under controlled laboratory conditions for a period of typically 14 days. Growth parameters such as shoot length, frond number, and biomass are measured to determine effects on plant development.
The test provides concentration–response relationships and allows for the determination of endpoints such as the median effective concentration (ErC₅₀) and the No Observed Effect Concentration (NOEC).
By incorporating sediment exposure, this assay better represents field-relevant conditions, offering crucial data for environmental risk assessment of chemicals that may partition into sediments and affect benthic and aquatic plant communities.
