Occurrence of bromate, chlorite and chlorate in drinking waters disinfected with hypochlorite reagents. Tracing their origins

Bromate was first reported as a disinfection by-product from ozonated waters, but more recently it has been reported also as a result of treatment using hypochlorite solutions worldwide. The aim of this study was to study the scope of this phenomenon in the drinking waters ( n = 509) of Castilla y L...

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Bibliographic Details
Published in:	The Science of the total environment Vol. 408; no. 12; pp. 2616 - 2620
Main Authors:	Garcia-Villanova, Rafael J., Oliveira Dantas Leite, M. Vilani, Hernández Hierro, J. Miguel, de Castro Alfageme, Santiago, García Hernández, Cristina
Format:	Journal Article
Language:	English
Published:	Kidlington Elsevier B.V 15-05-2010 [Amsterdam; New York]: Elsevier Science Elsevier
Subjects:	Applied sciences Bromate Bromates Bromates - analysis Byproducts Calcium hypochlorite Chlorate Chlorates Chlorates - analysis Chlorides - analysis Chlorite Chlorites Disinfectants - chemistry Drinking water Drinking water and swimming-pool water. Desalination Environmental Monitoring Exact sciences and technology Hypochlorous Acid - chemistry Pellets Pollution Rest Sodium hypochlorite Water Pollutants, Chemical - analysis Water Purification Water Supply - analysis Water treatment and pollution Europe Spain Spain, Castilla y Leon Sodium hypochlorite Calcium hypochlorite Drinking water Chlorite Chlorate Bromate Drinking water treatment Bromates Chlorites Reaction product Chlorates Disinfection Secondary pollutant Concentration measurement Water quality Hypochlorites
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Summary:	Bromate was first reported as a disinfection by-product from ozonated waters, but more recently it has been reported also as a result of treatment using hypochlorite solutions worldwide. The aim of this study was to study the scope of this phenomenon in the drinking waters ( n = 509) of Castilla y León, Spain, and in the hypochlorite disinfectant reagents. Two thirds of the treated waters monitored were found to have bromate concentrations higher than 1 µg/l, and of them a median value of 8 µg/l and a maximum of 49 µg/l. These concentrations are higher than those reported so far, however, a great variability can be found. Median values for chlorite were of 5 µg/l, and of 119 µg/l for chlorate. Only 7 out of 40 hypochlorite feedstock solutions were negative for bromate, the rest showing a median of 1022 mg/l; and 4 out of 14 calcium hypochlorite pellets were also negative, the rest with a median of 240 mg/kg. Although bromate is cited as potentially added to water from calcium hypochlorite pellets, no reference is found in scientific literature regarding its real content. Chlorite (median 2646 mg/l) and chlorate (median 20,462 mg/l) and chlorite (median 695 mg/kg) and chlorate (median 9516 mg/kg) were also monitored, respectively, in sodium hypochlorite solutions and calcium hypochlorite pellets. The levels of chlorite and chlorate in water are considered satisfactory, but not those of bromate, undoubtedly owing to the high content of bromide in the raw brines employed by the chlor-alkali manufacturers. Depending on the manufacturer, the bromate concentrations in the treated waters may be very heterogeneous owing to the lack of specification for this contaminant in the disinfectant reagents —the European Norms EN 900 and 901 do not mention it.
Bibliography:	http://dx.doi.org/10.1016/j.scitotenv.2010.03.011 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0048-9697 1879-1026
DOI:	10.1016/j.scitotenv.2010.03.011