Nature and extent of the interactions of humic acids with a water treatment algicide and a fungicide

Equilibrium dialysis and molecular sieve chromatography were employed to evaluate the interactions between humic acids (HA) and a water treatment algicide, poly[oxyethylene(dimethyliminio)ethylene dimethyliminio)ethylene dichloride (WSCP), and a fungicide, 2-(thiocyanomethylthio)benzothiazole (TCMTB). WSCP exhibited saturable, reversible binding to HA The interaction between HA and WSCP was found to be of sufficient magnitude that naturally occurring HA concentrations will have significant impacts on the bioavailabity, toxicity and fate of WSCP in the environment. No interaction between HA and TCMTB was detected.