State of the Art of Triad-Based Ecological Risk Assessment: Current Limitations and Needed Implementations in the Case of Soil Diffuse Contamination

Soils can be sinks of pollutant mixtures, whose effects on terrestrial ecosystems are not of obvious interpretation. Risk assessment is rather codified and many approaches can be used. Nevertheless, there are still uncertainties remaining when dealing with diffuse pollution, including chronic inputs of low, sublethal, concentrations of mixtures of micropollutants. In this paper, we reviewed through a comprehensive literature analysis one of the latest promising methodologies, the triad approach, in order to understand its area of application in terrestrial ecosystems, the ways of applicability and the reported actual usage. In the case of diffuse pollution, where all the criteria of the triad approach can differ in their indication, we show that some improvements have to be made in either the chemical, ecological or ecotoxicological approaches to be able to clearly identify the risk and to address the uncertainties linked to the low, sublethal contents of contaminants.