Effect of Control Sediment Composition on the Metabolomic Responses of Grandidierella japonica during Toxicity Testing Using Copper at an Acutely Toxic Level

Abstract

Control sediment in whole-sediment toxicity testing has a wide range of properties, but the effects of the sediment composition at the molecular level have not been investigated. Therefore, we adopted a metabolomic approach to assess the effects of sediment composition at the molecular level, in particular the effects of control sediment composition on the metabolomic responses of test species under control and test conditions. The estuarine amphipod Grandidierella japonica was incubated in test chambers with four types of sediment, and the metabolomes of G. japonica were analyzed using a high-resolution mass spectrometer. Metabolomes of G. japonica exposed to a copper (Cu) solution were also obtained in the same way. We found that the metabolomic profiles were affected by the composition of the control sediment and exposure to Cu and that the exposure to Cu caused a more dominant influence than the change in the compositions of control sediments. However, the metabolites that had key roles to discriminate between the control and Cu exposure groups differed between the tested control sediments. Our results suggest that the effects of control sediment are smaller than those of toxicant exposure, and toxicity assessment using metabolomics is possible regardless of the sediment type.