This research investigated the formation potential (FP) for haloacetonitriles (HANSs), haloketones (HKs), chloropicrin (CP) and trihalomethanes (THMs) under conditions of constant DOC, constant Cl:DOC ratio, variable [Br] and variable apparent molecular weight (AMW) for coagulated water from a full-scale water treatment plant. Coagulated, high humic water (4.5 mg DOC/L) was fractionated into <1K, <10K, and <30K MWCO fractions. The DOC of the fractions was adjusted to the same value (e.g., ~ 2 mg/L). Fractions were chlorinated at 3:1 Cl,:TOC ratio under varying [Br]. Observed, non-THM species occurred at low concentrations (<0.3-9.0 ug/L). As expected THMFP speciation was strongly affected by Br:Cl ratio; this research demonstrated similar effects on specific HANs and HKs. Increasing quantities of brominated HANs and HKs were observed with increasing [Br]. DCANFP remained relatively constant while BCANFP and DBANFP increased with increasing [Br]. Increases in brominated species resulted in a larger relative change in THANFP than TTHMFP, suggesting that more HAN precursor material reacted when Br was present. Elevating Br:Cl to 0.03 resulting in HANFPs comparable to CHBr,FP. Change in HAN and HK species with respect to molecular weight cutoff (MWCO) and coagulated-raw water comparisons suggest that HANFP results from reaction with small, reactive, nitrogen containing compounds (<1K AMW) and larger (<30,000 MWCO) proteinaceous matter. / Master of Science