Validating sample preservation techniques and holding times for the approved compliance monitoring methods for haloacetic acids under the US EPA's stage 1 D/DBP rule

• Published in: Water research (Oxford) Vol. 38; no. 4; pp. 895 - 902
• Main Authors: Pepich, Barry V, Domino, Mark M, Dattilio, Teri A, Fair, Patricia S, Munch, David J
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2004; Elsevier Science
• Subjects: Acetic Acid - analysis; Applied sciences; Chloramines; Chloramines - chemistry; Disinfection; Disinfection byproducts; Drinking water and swimming-pool water. Desalination; Exact sciences and technology; Haloacetic acids; Halogens; Pollution; Reproducibility of Results; Specimen Handling; Time Factors; United States; United States Environmental Protection Agency; Water Microbiology; Water Purification; Water treatment and pollution; United States; Haloacetic acids; Chloramines; Disinfection byproducts; Drinking water treatment; Microorganism growth; Chlorination; Microbiological testing; Reaction product; Pollutant formation; Tosylchloramide sodium; Disinfection; Ammonium chloride; Carboxylic acid; Water quality; Sample conservation; Total organic carbon; Halogen Organic compounds
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2003.09.040

Haloacetic acids (HAAs), which are formed during the disinfection of drinking waters with chlorine, are regulated by the US Environmental Protection Agency (EPA) under the Stage 1 Disinfectant/Disinfection Byproducts (D/DBP) Rule. Recently, three studies have been reported indicating that low concentrations of HAAs can also be formed during disinfection with chloramines. Methods currently approved for compliance monitoring under the Stage 1 Rule arrest the chlorine-mediated formation of HAAs by adding ammonium chloride, which forms chloramines. Studies were undertaken using an in-process water that favored the formation of HAAs with moderate total organic carbon concentration and high levels of chlorine to investigate the potential formation of HAAs under sample storage conditions. The ammonium chloride-quenched sample did form a small amount of HAAs, but total formation over a period equal to the 14-day sample storage time was less than 2 μg/l, whereas the unquenched samples increased 41 μg/l during the same period. Pour plate studies indicated that chlorinated drinking waters quenched with ammonium chloride are protected from microbial growth, which is an important additional advantage to this preservation scheme. The presence of a combined chlorine residual should prevent microbial degradation of HAAs in samples. These studies support the preservation protocols and the sample storage times promulgated for compliance monitoring under the Stage 1 D/DBP Rule.