Use of whole-body and subcellular Cu residues of Lumbriculus variegatus to predict waterborne Cu toxicity to both L. variegatus and Chironomus riparius in fresh water

Abstract

We tested the use of whole-body and subcellular Cu residues (biologically-active (BAM) and inactive compartments (BIM)), of the oligochaete Lumbriculus variegatus to predict Cu toxicity in fresh water. The critical whole-body residue associated with 50% mortality (CBR50) was constant (38.2–55.6μgg−1 fresh wt.) across water hardness (38–117mgL−1 as CaCO3) and exposure times during the chronic exposure. The critical subcellular residue (CSR50) in metal-rich granules (part of BIM) associated with 50% mortality was approximately 5μgg−1 fresh wt., indicating that Cu bioavailability is correlated with toxicity:subcellular residue is a better predictor of Cu toxicity than whole-body residue. There was a strong correlation between the whole-body residue of L. variegatus (biomonitor) and survival of Chironomus riparius (relatively sensitive species) in a hard water Cu co-exposure. The CBR50 in L. variegatus for predicting mortality of C. riparius was 29.1–45.7μgg−1 fresh wt., which was consistent within the experimental period; therefore use of Cu residue in an accumulator species to predict bioavailability of Cu to a sensitive species is a promising approach.