The objective of this study was to investigate the effect of bromide ion on the distribution of haloacetic acid (HAA) species resulting from the chlorination and chloramination of waters containing aquatic humic substances. Aquatic humic substances were extracted from a surface water and a groundwater and were chlorinated and chloraminated under standard conditions at pH 8 and pH 6 in the presence of bromide concentrations ranging from 0 to 25 µM (0-2 mg/L). The treated waters were analyzed for all nine of the HAA species containing bromine and chlorine. Standards for bromodichloroacetic acid and dibromochloroacetic acid were not commercially available but were synthesized for use in this study. Bromochloro-, bromodichloro-, and dibromochloroacetic acid were readily formed and constituted at least 10% of the total HAA concentration in waters containing as little as 1.2 µM (0.1 mg/L) bromide. The mixed bromochloro HAA species were major components of the total HAA concentration at bromide concentrations found in raw drinking waters. Distribution of the HAA species among the mono-, di-, and trihalogenated forms appeared to be independent of bromide concentration.

IntroductionKenya experienced widespread cholera outbreaks in 1997-1999 and 2007-2010. The re-emergence of cholera in Kenya in 2015 indicates that cholera remains a public health threat. Understanding past outbreaks is important for preventing future outbreaks. This study investigated the relationship between cholera occurrence in Kenya and various environmental and demographic factors related to water, sanitation, socio-economic status, education, urbanization and availability of health facilities during the time period 2008-2013.MethodsThe primary outcome analyzed was the number of cholera cases at the district level, obtained from the Kenya Ministry of Health's national cholera surveillance records. Values of independent variables were obtained from the 2009 Kenya Population and Housing Census and other national surveys. The data were analyzed using a zero-inflated negative binomial regression model.ResultsMultivariate analysis indicated that the risk of cholera was associated with open defecation, use of unimproved water sources, poverty headcount ratio and the number of health facilities per 100,000 population (p < 0.05). No statistically significant association was found between cholera occurrence and education, percentage of population living in urban areas or population density.ConclusionThe Sustainable Development Goals and Kenya's blueprint for development, Kenya Vision 2030, call for access to sanitation facilities and clean water for all by 2030. Kenya has made important economic strides in recent years but continues to be affected by diseases like cholera that are associated with low socio-economic status. Further expansion of access to sanitation facilities and clean water is necessary for preventing cholera in Kenya.

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