Disinfection effect of benzalkonium chloride (BAC) in isotopic carbon analysis of seawater: Influence of varying salt and BAC concentrations.

Abstract

Because the carbon isotoppic ratios (13C and 14C concentrations) of dissolved inorganic carbon (DIC) in natural water samples are altered by microorganisms during storage after sampling, addition of disinfectant is neccesarry. The authors have evaluated the possibility of benzalkonium chloride (BAC) as a safe and easy-to-handle disinfectant, but BAC has been reported to be less effective in seawater. In this study, in order to clarify the reason why the effect of BAC decreases in seawater, we evaluated the difference in bactericidal effect depending on the salinity of water samples and the amount of BAC added, using seawater sampled at the Fujimae tidal flat in Nagoya and groundwater collected from Tsukuba in Ibaraki Prefecture, and discussed the behavior of BAC and mutual effects among other components in the water samples.