English Abstract A project was started to study which standards reported
in IMP-water 1985-1989 are too high to prevent effects on Daphnia magna due
to long term exposure. First, no-effect-levels (NOECs) for individual
compounds were to be established. Second, a mixture of these compounds on
NOEC- level was to be tested on toxic effects. Due to fast developments in
water quality policy making the relevance of above mentioned research was
reducing. Therefore it was decided to stop this research project
prematurely and to report the results shortly. The experiments carried out
were reproduction/growth experiments with D. magna exposed to zinc, copper,
nickel, lead, parathion, lindane and sodiumlaurylsulphate (SLS). The values
were established in single experiments in Dutch Standard Water. The
experiments do not meet the validity requirements set by the European
Commission except sodiumlaurylsulphate. The reason is too much mortality in
the control or not dose related mortality. The cause of this mortality is
not known.
