Locatiespecifieke ecologische risicobeoordeling - praktijkonderzoek met de TRIADE-benadering deel 2

This report describes the results of a research programme on the application of the so-called TRIAD approach for site specific ecological risk assessment of soil pollution. The method means to optimise the estimation of actual ecological effects in a specific area or ecosystem, by gathering multiple evidence along various ways. The TRIAD includes three pillars consisting of chemical, toxicological and ecological measurements. Each pillar of the TRIAD can be extended over three tiers, representing low, middle and high levels of sophistication in research methods. In the second phase of the field research, three locations were investigated with emphasis on the selection of a local reference site and ecological measurements. The chemical, toxicological and ecological measurements were integrated into an effect estimation per TRIAD-unit and one overall assessment. Effects were scaled from 0 to 1 and divided into 3 colour-categories to obtain a better overview. Although most bioassays and ecological indicators were able to characterise the samples, they showed much lower effects than predicted from the measured concentrations of pollutants. The (chemical) Toxic Pressure method, based on Species Sensitivity Distributions, seems to give an overestimation of ecological effects. It is also less discriminating in situations of multiple substance pollution exceeding Serious Risk Levels.