Evaluation of plastic packaged water quality using health risk indices: A case study of sachet and bottled water in Accra, Ghana

Abstract

Plastic packaged water is the drinking water of choice for urban populations across Africa but its quality remains questionable in most developing countries. Six hundred (600) packages, consisting of sachet and bottled water, were sampled from two high-end companies in Accra (Ghana) and stored through their shelf lives under an average room temperature of 30 °C. The samples were tested for physicochemical quality and the presence of bacteria and phthalate esters at 2n × 3 periods, where n is the sampled batch number. The data were described and modelled with embedded Bayesian and Machine Learning algorithms in JASP0.16.0.0 and Argo-4.1.3. The results reported lower than regulated levels of electrical conductivity (163.66 μS/cm), alkalinity (39.67 mg/L), and residual chlorine (<0.01 mg/L) while the pH was generally within specification (6.5–7.7). All samples showed progressive biological contamination following the third week (sachet samples) and the sixth week (bottled water) of incubation. Initial samples, including raw water, processed bulk water and packaged water did not present detectable microbial growth. The total microbial load in sachet samples grew at 0.936 cfu/week and 1.006 cfu/week for the bottled samples although the results did not exceed 1000 cfu/L (0-976 cfu/100 mL). Modelled mean probability of infection was 1.196 × 10−4 in 67% of the samples. Raw and processed water samples did not show detectable levels of phthalate contaminants. The mean hazard index calculated on the individual hazard quotients of phthalates was 7.41 × 10−3 ± 8.20 × 10−4, suggesting lower acute risk potential. Mean integrated lifetime cancer risk (ILCR) was determined to be 1.53 × 10−3 ± 1.71 × 10−4 within a range of 2.86 × 10−4 and 7.18 × 10−3. Mean child ILCR was about 70% of adult ILCR and increased from 4.16 × 10−4 to 2.41 × 10−3 for sachet and 4.93 × 10−4 to 7.18 × 10−3 for bottled water. For adult ILCR, sachet water presented 2.86 × 10−4 to 1.65 × 10−3, and 3.38 × 10−4 to 4.93 × 10−3 for bottled water. This study confirmed the presence of phthalates and pathogenic bacteria in the samples, at-risk levels that require mitigation.