title: Bioavailability of contaminants estimated from uptake rates into soil invertebrates.
abstract: It is often argued that the concentration of a pollutant inside an organism is a good indicator of its bioavailability, however, we show that the rate of uptake, not the concentration itself, is the superior predictor. In a study on zinc accumulation and toxicity to isopods (Porcellio scaber) the dietary EC(50) for the effect on body growth was rather constant and reproducible, while the internal EC(50) varied depending on the accumulation history of the animals. From the data a critical value for zinc accumulation in P. scaber was estimated as 53 microg/g/wk. We review toxicokinetic models applicable to time-series measurements of concentrations in invertebrates. The initial slope of the uptake curve is proposed as an indicator of bioavailability. To apply the dynamic concept of bioavailability in risk assessment, a set of representative organisms should be chosen and standardized protocols developed for exposure assays by which suspect soils can be evaluated.
authors.affiliation: Vrije Universiteit, Institute of Ecological Science, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands. nico.van.straalen@ecology.falw.vu.nl
authors.forename: N M
authors.initials: NM
authors.lastname: van Straalen
authors.forename: M H
authors.initials: MH
authors.lastname: Donker
authors.forename: M G
authors.initials: MG
authors.lastname: Vijver
authors.forename: C A M
authors.initials: CA
authors.lastname: van Gestel
mesh_terms: D000818:Animals; D001682:Biological Availability; D004435:Eating; D004784:Environmental Monitoring / Q000379:methods*; D007448:Invertebrates / Q000378:metabolism*; D007928:Lethal Dose 50; D018570:Risk Assessment; D012989:Soil Pollutants / Q000493:pharmacokinetics* / Q000633:toxicity; D018675:Toxicity Tests; D015032:Zinc / Q000493:pharmacokinetics* / Q000633:toxicity
chemical_list: D012989:Soil Pollutants; D015032:Zinc