Spatial Variability and Uncertainty in Ecological Risk Assessment:  A Case Study on the Potential Risk of Cadmium for the Little Owl in a Dutch River Flood Plain

Abstract

This paper outlines a procedure that quantifies the impact of different sources of spatial variability and uncertainty on ecological risk estimates. The procedure is illustrated in a case study that estimates the risks of cadmium for a little owl (Athene noctua vidalli) living in a Dutch river flood plain along the river Rhine. A geographical information system (GIS) was used to quantify spatial variability in contaminant concentrations and habitats. It was combined with an exposure and effect model that uses Monte Carlo simulation to quantify parameter uncertainty. Spatial model uncertainty was assessed by the application of two different spatial interpolation methods (classification and kriging) and foraging ranges. The results of the case study show that parameter uncertainty is the main type of uncertainty influencing the risk estimate, and to a lesser extent spatial variability, while spatial model uncertainty was of minor importance. Compared to the deterministically calculated hazard index for the little owl (0.9), inclusion of spatial variability resulted in a median hazard index that can vary between 0.8 and 1.4. It is concluded that a single estimator for a whole flood plain may over- or underestimate risks for specific parts within the flood plain. Further research that expands the procedure presented in this paper is necessary to improve the incorporation of spatial factors in ecological risk assessment.

Framework for traits‐based assessment in ecotoxicology

“…case studies to explain differences in exposure, for example in evaluating the potential risks of Cd for the little owl Athene noctua in a river floodplain (Kooistra et al 2005) and Hg poisoning in the loon Gavia immer (Nacci et al 2005). Furthermore, the duration and intensity of direct contact with a toxicant may vary with the lifespan and home range of an organism.…”

Heavy-Metal Concentrations in Small Mammals from a Diffusely Polluted Floodplain: Importance of Species- and Location-Specific Characteristics

“…1996; Kooistra et al . 2001, 2005). Except for the soil contaminant levels, these parameters for the calculation of accumulation risks are generally derived from literature data from inland area or laboratory studies.…”

Site‐Specific Applications of Probabilistic Health Risk Assessment: Review of the Literature Since 2000

“…Wageningen University and Research Centre (The Netherlands); Radboud University (The Netherlands) Kooistra et al (2001Kooistra et al ( , 2005 Evaluated exposure and risk associated with PCB contamination from polysulphide sealants Performed deterministic and probabilistic calculations for cancer and noncancer risks associated with soil ingestion and dermal contact with PCBs from polysulphide sealants used in outdoor seams between concrete clocks in prefabricated residential buildings.…”

“…Distributions for cancer risk and hazard quotients were calculated for exposure to PCB-contaminated soils surrounding an industrial site in Finland (Priha et al, 2005). Spatially explicit ecological risk assessment with probabilistic exposure estimation was conducted at a chemical industry site in Italy contaminated with 1,2,4-trichlorobenzene (Zolezzi et al, 2005) and at a cadmium-contaminated river floodplain in the Netherlands (Kooistra et al, 2001(Kooistra et al, , 2005. Spatial components of ecological exposure are incorporated into risk assessment by linking geographical information systems (GIS) with probabilistic models for estimating exposure.…”