title: Disinfection by-product formation and mitigation strategies in point-of-use chlorination with sodium dichloroisocyanurate in Tanzania.
abstract: Almost a billion persons lack access to improved drinking water, and diarrheal diseases cause an estimated 1.87 million deaths per year. Sodium dichloroisocyanurate (NaDCC) tablets are widely recommended for household water treatment to reduce diarrhea. Because NaDCC is directly added to untreated water sources, concerns have been raised about the potential health impact of disinfection by-products. This study investigated trihalomethane (THM) production in water from six sources used for drinking (0.6-888.5 nephelometric turbidity units) near Arusha, Tanzania. No sample collected at 1, 8, and 24 hours after NaDCC addition exceeded the World Health Organization guideline values for either individual or total THMs. Ceramic filtration, sand filtration, cloth filtration, and settling and decanting were not effective mitigation strategies to reduce THM formation. Chlorine residual and THM formation were not significantly different in NaDCC and sodium hypochlorite treatment. Household chlorination of turbid and non-turbid waters did not create THM concentrations that exceeded health risk guidelines.
authors.affiliation: Enteric Diseases Epidemiology Branch, and Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. dlantagne@cdc.gov
authors.forename: Daniele S
authors.initials: DS
authors.lastname: Lantagne
authors.forename: Fred
authors.initials: F
authors.lastname: Cardinali
authors.forename: Ben C
authors.initials: BC
authors.lastname: Blount
mesh_terms: D002713:Chlorine / Q000494:pharmacology; D003967:Diarrhea / Q000517:prevention & control*; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection; D005618:Fresh Water / Q000382:microbiology; D054879:Halogenation; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013636:Tanzania; D014227:Triazines / Q000009:adverse effects* / Q000494:pharmacology; D022882:Trihalomethanes / Q000494:pharmacology; D014871:Water Microbiology / Q000592:standards; D014874:Water Pollutants, Chemical / Q000009:adverse effects; D018508:Water Purification; D014881:Water Supply / Q000706:statistics & numerical data*; D014944:World Health Organization
chemical_list: D004202:Disinfectants; D014227:Triazines; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; D002713:Chlorine; D012973:Sodium Hypochlorite; C011765:troclosene