Biofouling in industrial water systems is normally prevented by the us
e of bactericides. However, bactericide programmes often fail owing to
the lack of suitable techniques for determining the in situ bacterici
de concentration and this usually results in either inadequate or exce
ssive bactericide concentrations. In this study, the Sterikon(R) bioin
dicator was evaluated for determining the minimum inhibitory concentra
tions of 5 industrial bactericides (dichlorophen, sulphone, thiocarbam
ate, isothiazolone and a quaternary ammonium compound) for the monitor
ing of the concentrations of these compounds in industrial water syste
ms. The results indicated that the Sterikon(R) bioindicator can be use
d for the determination of bactericide concentrations.