Gertie H P Arts
Alterra Wageningen University and Research Centre, The Netherlands
Title: Effects of linuron on a rooted aquatic macrophyte in sediment-dosed test systems
Biography
Biography: Gertie H P Arts
Abstract
Effects of linuron on the sediment-rooted aquatic macrophyte Myriophyllum spicatum L. Were studied in sediment-dosed test systems following an OECD test guideline with extended test duration. Sediment, pore water, overlying water and macrophyte shoots were sampled weekly for chemical analyses. Linuron was stable in the sediments. Sediment and pore water concentrations were in equilibrium aft er 48 h. Overlying water concentrations increased over time, but did not reach equilibrium with pore water concentrations and were 1000 times lower. Mass balances showed a rapid uptake of linuron by macrophyte roots. Known pathways and the compound’s properties support the conclusion that Myriophyllum takes up linuron from pore water directly through the roots. Modeling supported the conclusions that high concentrations in the shoots could be explained by translocation of linuron by the roots to the shoots. The fluxes calculated for linuron support this interpretation.
At the experimental start, several pathways played a role, i.e. linuron fl uxes from pore water to overlying water and from pore water to roots. The flux from pore water to overlying water decreased later, while the translocation fl uxes from roots to shoots increased. Hence, eff ects on macrophytes in this type of sediment toxicity test should be expressed in terms of pore water concentrations. Sensitivity of water- and sediment-dosed test systems will be discussed in the light of compound properties.