title: Estimation of demographic toxicity through the double bootstrap.
abstract: Toxicity to organisms is usually expressed in terms of an observable effect on individuals from which a summary endpoint (such as the NOEC or ECx) is derived for risk assessment and environmental quality standards. However, toxicity evaluated in terms of a demographic endpoint may be more relevant to such regulatory applications. In this paper the effect of toxicity on population growth rate r is explored in tandem with a 'double bootstrap' to incorporate uncertainty. Exemplifying the approach with a set of individualized life table response data obtained for Daphnia magna exposed to zinc sulphate solution, the influence of increasing concentrations is assessed. A demographic-based metric for r, the ErCx (effect on r concentration percentage), is defined to permit alternative population level estimation of a 'safe effect' concentration.
authors.affiliation: School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK.
authors.forename: Eric P M
authors.initials: EP
authors.lastname: Grist
authors.forename: Mark
authors.initials: M
authors.lastname: Crane
authors.forename: Claire
authors.initials: C
authors.lastname: Jones
authors.forename: Paul
authors.initials: P
authors.lastname: Whitehouse
mesh_terms: D000818:Animals; D003621:Daphnia; D023381:Endpoint Determination; D015993:Life Tables; D008962:Models, Theoretical; D011157:Population Dynamics; D018570:Risk Assessment; D018675:Toxicity Tests; D014873:Water Pollutants / Q000633:toxicity*
chemical_list: D014873:Water Pollutants