Induction of mouthpart deformities in chironomid larvae exposed to contaminated sediments

The aim of the present study was to improve the cause–effect relationship between toxicant exposure and chironomid mouthpart deformities, by linking induction of mouthpart deformities to contaminated field sediments, metal mixtures and a mutagenic polycyclic aromatic compound metabolite (acridone). Mouthpart deformities in Chironomus riparius larvae were induced by both the heavy metal mixture and by acridone. A clear correlation between metal concentrations in the sediment and deformities incidence was only observed when the contaminated field sediments were left out of the analysis, probably because these natural sediments contained other toxic compounds, which could be responsible for a higher incidence of deformities than predicted by the measured metal concentrations only. The present study clearly improved the cause–effect relationship between toxicant exposure and the induction of mouthpart deformities. It is concluded that the incidence of mouthpart deformities may better reflect the potential toxicity of contaminated sediments than chemical analysis.

► We tested the induction of deformities in C. riparius in laboratory toxicity experiments.
► We used field sediments and spiked sediments with heavy metals and mutagenic PAC.
► Mouthpart deformities were induced both by heavy metal mixtures and by acridone.
► A correlation between metal concentrations in the sediment and deformities was found.
► Mouthpart deformities better reflect the toxicity of sediments than chemical analysis.