A simple in vitro test to monitor trace metal toxicity in aqueous samples

Abstract

We have studied the effect of test toxicants on electron transfer along the rotenone‐insensitive NADH‐cytochrome b₅ reductase of the outer mitochondrial membrane, using oxidized cytochrome c as the electron acceptor in a simple spectrophotometric assay. We show that this reaction is extremely sensitive to trace metals of environmental concern, detecting reliably as little as 10 nM Hg²⁺. The assay is reproducible, simple, fast and inexpensive, compares favourably with fish acute toxicity tests, and may become useful in the routine monitoring of waters for the presence of this class of pollutants.

Keywords:

• Mitochondria
• toxicity
• metals