Ecosysteemgerichte risicobeoordeling van stoffen : eindreport ecosysteemrendement

VakpublicatieInstitute of Environmental Science

Ecotoxicological models for Dutch environmental policy: Models to be addressed in the Stimulation Program Systems-Oriented Ecotoxicological Research (NWO/SSEO)

Contains fulltext : 32440.pdf (publisher's version ) (Open Access)91 p

BIOMAG : risicoanalyse van bodemverontreiniging van terrestrische vertebraten

Wetensch. publicatieInstitute of Environmental Science

Critical body residues linked to octanol-water partitioning, organism composition and LC50-QSARs: meta-analysis and model

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A probabilistic model for deriving soil quality criteria based on secondary poisoning of top predators II : Calculations for dichlorodiphenyltrichloroethane (DDT) and cadmium

A simplified food web with three trophic levels is designed: plants and invertebrates at the first, small birds and mammals at the second, and birds and beasts of prey at the third trophic level. Exposure of top predators via separate food chains is analyzed. However, most top predator species are exposed via more than one food chain (food web). Therefore, a species- specific approach is followed too, for which four bird of prey species and two beast of prey species with different food choices are selected: sparrow hawk, kestrel, barn owl, little owl, badger, and weasel. The most critical food chains for secondary poisoning of top predators are soil → worm/insect → bird → bird of prey for dichlorodiphenyltrichloroethane (DDT), and soil → worm → bird/ mammal → bird of prey for cadmium (Cd). The risk for the selected top predator species is much lower than the risk based on these critical food chains because the critical food chains constitute a minor part of their food webs. Species feeding on birds (sparrow hawk) and small carnivorous mammals (barn owl) are exposed to DDT and Cd to a much higher extent than species mainly feeding on small herbivorous mammals (kestrel and weasel). It is recommended to include exposure via the pathways soil → worm/insect → bird/mammal → top predator in procedures for derivation of environmental quality objectives for persistent and highly lipophilic compounds

A probabilistic model for deriving soil quality criteria based on secondary poisoning of top predators I : Model description and uncertainty analysis

In previous studies, the risk of toxicant accumulation in food chains was used to calculate quality criteria for surface water and soil. A simple algorithm was used to calculate maximum permissable concentrations [MPC = no- observed-effect concentration/bioconcentration factor(NOEC/BCF)]. These studies were limited to simple food chains. This study presents a method to calculate MPCs for more complex food webs of predators. The previous method is expanded. First, toxicity data (NOECs) for several compounds were corrected for differences between laboratory animals and animals in the wild. Second, for each compound, it was assumed these NOECs were a sample of a log- logistic distribution of mammalian and avian NOECs. Third, bioaccumulation factors (BAFs) for major food items of predators were collected and were assumed to derive from different log-logistic distributions of BAFs. Fourth, MPCs for each compound were calculated using Monte Carlo sampling from NOEC and BAF distributions. An uncertainty analysis for cadmium was performed to identify the most uncertain parameters of the model. Model analysis indicated that most of the prediction uncertainty of the model can be ascribed to uncertainty of species sensitivity as expressed by NOECs. A very small proportion of model uncertainty is contributed by BAFs from food webs. Correction factors for the conversion of NOECs from laboratory conditions to the field have some influence on the final value of MPC5, but the total prediction uncertainty of the MPC is quite large. It is concluded that the uncertainty in species sensitivity is quite large. To avoid unethical toxicity testing with mammalian or avian predators, it cannot be avoided to use this uncertainty in the method proposed to calculate MPC distributions. The fifth percentile of the MPC is suggested as a safe value for top predators