Estimation of demographic toxicity through the double bootstrap.
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.
Grist
Eric P M
EP
School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK.
Crane
Mark
M
Jones
Claire
C
Whitehouse
Paul
P
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*
D014873:Water Pollutants