Impact of natural and synthetic steroids on the survival, development and reproduction of marine copepods Tisbe battagliai/

Given recent reports suggesting that natural and synthetic steroids namely, oestradiol, oestrone and ethynylestra- diol. may be present in sewage effluent at levels which may impact on fish, it is pertinent to extend the ecological hazard evaluation for such substances to aquatic invertebrates. Studies have therefore been undertaken to address whether 17b-oestradiol, oestrone and 17a-ethynylestradiol can inhibit survival, development or reproductive output in Tisbe battagliai Crustacea, Copepoda, Harpacticoida.. This sexually reproducing species was selected since it is representative of a widespread group of aquatic Crustacea, is sensitive to environmental contaminants and is highly amenable to laboratory life-cycle studies. Newly released -24 h old. T. battagliai nauplii were exposed to individual steroids dissolved in sea water using the ecdysteroid, 20-hydroxyecdysone, as a positive control. and effects monitored in terms of survival, development and sex ratio after 10 days at 20"18C. Adult males and females were then paired and exposures continued to investigate effects on reproductive output 21 days total exposure.. In summary, the lowest 21 day No Observed Effect Concentrations based on these life-cycle parameters were: 20-hydroxyecdysone: 8.7 mg? ly1; oestrone: G100 mg? ly1; 17b-oestradiol: G100 mg? ly1; and 17a-ethynylestradiol: G100mg? ly1 all based on nominal concentrations.. These data are relevant for the development of an ecological risk assessment for oestrogenic steroids in the aquatic environment and should be extended to other invertebrate groups. As novel analytical techniques allow, future bioassay studies should be ideally supported by steroid analyses wherever possible.