EFFECT OF BROMIDE ION ON HALOACETIC ACID SPECIATION RESULTING FROM CHLORINATION AND CHLORAMINATION OF AQUATIC HUMIC SUBSTANCES

The objective of this study was to investigate the effect of bromide i on on the distribution of haloacetic acid (HAA) species resulting from the chlorination and chloramination of waters containing aquatic humi c substances. Aquatic humic substances were extracted from a surface w ater and a groundwater and were chlorinated and chloraminated under st andard conditions at pH 8 and pH 6 in the presence of bromide concentr ations ranging from 0 to 25 mu M (0-2 mg/L). The treated waters were a nalyzed for all nine of the HAA species containing bromine and chlorin e. Standards for bromodichloroacetic acid and dibromochloroacetic acid were not commercially available but were synthesized for use in this study. Bromochloro-, bromodichloro-, and dibromochloroacetic acid were readily formed and constituted at least 10% of the total HAA concentr ation in waters containing as little as 1.2 mu M (0.1 mg/L) bromide. T he mixed bromochloro HAA species were major components of the total HA A concentration at bromide concentrations found in saw drinking waters . Distribution of the HAA species among the mono-, di-, and trihalogen ated forms appeared to be independent of bromide concentration.