The effect of phthalate ester plasticisers tested as surfactant stabilised dispersions on the reproduction of the Daphnia magna

The phthalate ester plasticisers, di-2-ethylhexyl phthalate (DEHP), di-iso-nonyl phthalate (DINP), DINP produced by the "polygas" process (DINP-PG), di-n-nonyl/n-undecyl phthalate (L911P), di-n-octyl/n-decyl phthalate (L810P), di-iso-decyl phthalate (DIDP), di-iso-heptyl phthalate (DIHP), di-n-hexyl/n-decyl phthalate (L610P), di-undecyl phthalate (DUP), di-heptyl/nonyl phthalate (L79P), di-iso-undecyl phthalate (DIUP) and di-iso-tridecyl phthalate (DTDP) have been tested for acute and chronic toxicity to Daphnia magna. In addition, di-2-propylheptyl phthalate (DPHP) has been tested for chronic toxicity to Daphnia magna. The test organisms were exposed at a nominal concentration of 1 mg phthalate per litre presented as a dispersion with either "Tween 20" or "Marlowet R40". For the chronic studies, the nominal concentrations were verified by analysis, except for the L911P where, due to chromatographic difficulties, the test concentration could not be determined and this was estimated as 56% of nominal by analysis of the stock. The exposure period for the acute studies was 48 hours and the test organisms were monitored for notation in the surface layer and mortalities. The chronic studies were conducted over 21 days. The end points were the numbers of young produced, survival of the parent animals and the length of the parent animals at the end of the 21 day exposure period. No significant negative effects, relative to the controls, were seen in either the acute or the chronic studies. (C) 1998 Elsevier Science Ltd.