Real-Time Detection of Potassium Cyanide Pollution in Surface Waters Using Electric Organ Discharges Wave Emitted by the Tropical Fish, Apteronotus Albifrons

Abstract

A new biological early warning system which exploits the electric organ discharges (EOD) of the South American tropical fish Apteronotus albifrons (Gymnotiformes) is described. Thanks to its neurogenic electric organ, this fish continually emits wave form electric signals. The time variations of the EOD frequency and wave form, two characteristics known to be very stable under constant ambient conditions, were recorded and analysed in a closed circuit to derive therefrom an assessment of the ability of A. albifrons to detect the presence of potassium cyanide. The ultimate aim is to incorporate the technique into a system for detecting changes in the quality of surface waters. The KCN detection threshold was found to be 35 µg.L−1. The response times in 50 % of fish sensors to detect the different cyanide concentrations tested (i.e. 35, 45, 70, 125 and 180 µg.L−1) were always shorter than half an hour. Minor cyanide concentrations provoked a fall in the EOD frequency while the number of pulses emitted per s...