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(303) Deriving environmental quality standards for water: progress towards integrating endocrine disrupting endpoints in standard setting. Brighty, Geoff1, Whitehouse, Paul 2, 1 2 ABSTRACT- Environmental Quality Standards (EQS) are target chemical concentrations for the aquatic environment that aim to protect the most sensitive species in the ecosystem. Chemical hazard data, typically relating to growth, reproduction or lethality endpoints, are critically assessed to establish the most sensitive species and lowest credible effect concentration. The EQS is derived by dividing the lowest effect concentration by an extrapolation factor to account for uncertainty in the data and the potential for the most sensitive species not having been tested. Whereas EQSs generally have been based on acute lethality datasets, the challenge today is how to incorporate other test endpoints arising from chronic sublethal assessments to ensure that the EQS adequately protects the environment. This is highlighted by substances that exhibit very low toxicity, yet are now known still to induce biological effects at concentrations many times (1000 - 1,000,000) less. Also, additive interactions have been shown for chemically-similar substances exposed below NOECs, leading to adverse health effects. The Environment Agency is particularly aware of endocrine disrupting effects in rivers in the UK caused by steroidal oestrogens and alkylphenols. The presentation will discuss progress towards encompassing endocrine disrupting and other endpoints within the framework of standard setting for these priority endocrine disrupting substances. Key words: environmental quality standard, endocrine disruptors, chronic sublethal assessments, steroid oestrogens |
