DBP formation potential of aquatic humic substances

Aquatic humic substances (AHSs) in water generate potentially harmful disinfection by-products (DBPs) such as haloacetic acids (HAAs) and trihalomethanes (THMs) during chlorination. AHSs from two Arkansas reservoirs were characterizede to define source, identify meta-dihydroxybenzene (m-DHB) structures as probable DBP precursors, and evaluate predicted HAA and THM formation potentials. Elemental nitrogen content 0.5 μeq/mg, δ 13 C values of -27%, and low yields of syringyl phenols found by cupric oxide (CuO) oxidation yielded fewer m-DHB structures in Maumelle AHSs than in Winona AHSs. A higher 3,5-dihydroxy-benzoic acid (3,5-DHBA) content correlated with increased HAA and THM formation potential. The 3,5-DHBA concentration in Winoma AHSs was similar to range found in AHSs extracted from deciduous leaf litter, twigs, and grass leachates.