Comparison of Halophenol, Halonitrophenol, and Halosalicylic Acid Formation vs 1–2 Carbon DBP Formation during Chlorination and Chloramination of Surface Waters

Although haloaromatic disinfection byproducts (DBPs) are considered an important component of nonvolatile, high molecular weight DBPs, little research has compared haloaromatic DBP formation to the conventional 1–2 carbon DBPs during chlorination or chloramination of authentic surface waters. This study compared the concentrations of 15 halophenols, 5 halonitrophenols, and 8 halosalicylic acids to 28 1–2 carbon DBPs in samples collected in two rivers upstream and downstream of wastewater impacts, in a municipal wastewater effluent, and in five algal-impacted reservoirs treated with chlorine alone or chlorine for 1 h followed by chloramination. Halophenols and halosalicylic acids reached ∼10–600 ng/L within 2–12 h during chlorination. Halophenols degraded faster than halosalicylic acids thereafter, and ∼10–30 ng/L halosalicylic acids remained after 5 d. During chlorination/chloramination, both halophenols and halosalicylic acids remained near the levels formed during the first 1 h of chlorine contact. Halonitrophenols formed at ∼10–140 ng/L but were stable during chlorination and chlorination/chloramination. In contrast, 1–2 carbon DBPs formed at ∼50–820 μg/L, accumulating during chlorination but remaining at levels formed during the initial 1 h chlorine contact during chlorination/chloramination. The organic matter in the river samples was more potent at producing aromatic DBPs than the algal-impacted organic matter. Although the trends in halosalicylic acid concentrations during chlorination were consistent with previous observations of overall cytotoxicity, these specific haloaromatic DBPs contributed substantially less to cytotoxicity than the 1–2 carbon DBPs.