Effect of Seawater Intrusion on the Formation of Chlorinated and Brominated Trihalomethanes in Coastal Groundwater

Around the world, coastal groundwater is increasingly subject to seawater intrusion (SWI). The quality and characteristics of such waters differ from those surface groundwater. In current study, trihalomethane (THM) formation under varying levels SWI, natural organic matter (NOM), chloride-to-bromide (Cl/Br) ratio was evaluated. Different SWI were simulated by mixing deionized water with real (RSW) collected Indian Ocean or synthetic (SSW) volumes 0% 3%. Humic acid (0 5 mg/L) added represent NOM at concentrations mimicking dissolved carbon. chlorine demand samples significantly correlated concentrations. THM concentration in SSW increased 12.64 µg/L 105.34 after 24 h 115.8 48 for an increase 3% volume seawater. For RSW, maximum THMs 119.2 µg/L, 126.4 µg/L. An seawater-intruded resulted increasing THMs, especially tribromomethane. However, increment higher lower compared that low concentration. Chlorine positively only bromide Cl/Br a concomitant brominated THMs. bromine substitution factor corresponding 0.25–3% decreased 2.67 1.81 over reaction time h, indicating shift TBM dominance chlorinated