Project
Ecotoxicity of metal mixtures to aquatic communities: something from nothing?
Chemical contamination is still a likely reason for EU waterbodies not to reach a U+201Cood ecological
statusU+201D However, risk assessment of contaminated waterbodies is mainly focused on a substanceby-
substance basis, while mixed contamination is the rule rather than the exception. This is
definitively the case for toxic trace metals such as zinc, nickel and copper, which often occur close to
their legally allowed environmental limits. Chronic ecotoxicity data, many of which generated and
analyzed by the applicants in a recently concluded joint FWO project, have shown significant
mixture effects in individual species. Even in cases where each individual metal was harmless, the
metals caused significant harm when dosed in combination. This is called the U+201Comething from
nothingU+201Dphenomenon. Indirect evidence and standard risk modeling suggest that this phenomenon
could even be more pronounced in certain multi-species communities, for instance because
synergies could emerge via the foodweb, but there is hardly any experimental data to evaluate this.
The general objective of this project is therefore to quantify and increase our understanding of
metal mixture effects on planktonic freshwater community structure and function. We will combine
experimental approaches with ecological modelling to identify conditions leading to U+201Comething
from nothingU+201Deffects on communities. Our research will ultimately find its application in improving
metal mixture risk assessment.