The toxicity of Cu2+ to Microcystis aeruginosa using dielectric spectroscopy

Abstract

Dielectric spectroscopy (DS) was utilized to investigate the toxicity of the Cu2+ solution to Microcystis aeruginosa. It was found that 0.04 mM Cu2+ had no effect on dielectric increment, whereas the Cu2+ concentrations above 0.1 mM decreased the value of Δɛ/Δɛ intact. The toxic effect of Cu2+ on M. aeruginosa cells was time-dependent and concentration-dependent. There was a threshold concentration between 0.04 mM and 0.1 mM, which affected the cell membrane, suggesting that Cu2+ at the concentrations higher than 0.1 mM caused serious plasmalemma damage to M. aeruginosa cells. The addition of 1 mM Ca2+ or Mg2+ did not protect M. aeruginosa cells from 1 mM Cu2+ toxicity. The study demonstrates that DS monitors cell biomass facilitating observation of the toxic effects of metal ions.