An analysis of the physico-chemical and microbial quality of sachet water in Lilongwe, Malawi: Implication on public health and WASH Policies

Abstract

Informally sachet water is an important source of drinking water for the majority of people lacking access to public piped sources. In Malawi, sachet water is popular but not regulated, and information about its quality and hygienic practices followed during production are unclear and rarely available. This study investigated the physico-chemical and microbial quality of hand-filled sachet drinking water in Lilongwe City, Malawi, and its public health and WASH policy implications. The study deployed an experimental design to generate primary data and a mixed-method research to acquire information about the source of water used in sachet water production. The water samples (n = 90) were randomly purchased and obtained from sachet water producers in Areas 1, 18, 25, 36, 49, and 57. The samples were preserved in a sample carrier containing ice packs and transported to Government Central Water Laboratory (Lilongwe) to assess their physico-chemical and microbiological quality. The samples were analysed for pH, total dissolved solids (TDS), electrical conductivity (EC), turbidity, iron (Fe), Arsenic (As), Manganese (Mn), Nitrate (NO3−), Chloride (Cl−), Fluoride (F−), and Escherichia coli (E-coli) by using standard methods as outlined in APHA (2012) and Malawi Standard guidelines. Compliance with Malawi Standards 214 (2004) and WHO (2011) guidelines for drinking water was examined using sigma capability and error bar. An analysis of variance (ANOVA) was performed to assess the difference in water quality parameters between the location of sample collection. The results showed that pH, Cl−, F−, and Turbidity were significantly different between the location in Lilongwe (p < 0.05) while E.coli, EC, TDS, Mn, Fe, and NO3− were not. The majority of the samples (72.22%, n = 90) were contaminated with E coli and therefore failed to comply with both MS 214 (2004) and WHO 2011 permissible limit for drinking water quality. The results further showed that some sachet samples (32.22%, n = 90) did not comply with the MS 214 (2013) turbidity maximum limit of 1 NTU. Further, majority of the samples (97.78%, n = 90) had low fluoride levels below the minimum Malawixiv standard (214) of 0.70 mg/L while few samples (2.22% n = 90) from areas 1 and 57 were above the permissible limit set by both the aforementioned standards hence were non-compliant. Furthermore, few samples (8%, n = 90) from areas 18, 25, and 36 did not comply with the minimum permissible pH limit of 6.50 set by WHO guidlines. Since the country does not have regulations and legislation governing the production and marketing of sachet water, the study recommends the formulation of the same to safeguard the health of consumers. This study further recommends strict inspection of sachet water products from relevant government offices to improve sachet water quality. There is also a need for awareness campaigns aimed at civic educating sachet water producers on best hygiene practices during production to prevent contamination.