Assessment of levels and health risk of Potentially Toxic Elements (PTEs) in selected sachet water packaged from groundwater resources in Ogun State, Nigeria

Abstract

BackgroundSachet water is a source of affordable drinking water for low-income socioeconomic class. However, contamination by potentially toxic elements (PTEs) could pose severe adverse health risk to consumers. ObjectiveThe present study aimed at assessing the levels and health risk of PTEs in selected sachet water samples packaged from groundwater resources in Ogun State, Nigeria. MethodsA total of 140 bags of selected sachet water brands were purchased and analysed for eleven PTEs (some of which are rarely reported in Nigeria) using inductively coupled plasma - optical emission spectrophotometer. Recovery experiment was conducted to validate the performance of the used analytical instrument. Blank samples were also run to cancel the matrix effect of the analysing reagents, and to calculate the limit of detection. PTE data were evaluated for simple descriptive and inferential statistics using SPSS for Windows. Health risk assessment was conducted for hazard quotient (HQ), hazard index (HI) and cancer risk (CR). ResultsChromium (Cr) was the highest observed PTE in sachet water from Asero (707±1102 µg L−1), Isolu (363±374 µg L−1) and Makun-Shagamu (359±204 µg L−1) sites. The concentrations of Cr were higher than the permissible limit of the World Health Organization in 63% of the sachet water samples. Furthermore, the average contents of lead (Pb) and thallium (Tl) were observed at higher concentrations than the acceptable limits. The HQs exceeding the permissible threshold of 1.0 were observed for silver (Ag), aluminium (Al), arsenic (As), cadmium (Cd), Cr and Tl in 29% of the sachet water consumed by adults and children; indicating adverse health effects. The CRs of Cd and Cr at all the sampling locations, and As at few sites were higher than the acceptable limit of 1 × 10−4; suggesting possible development of cancer by the consumers. ConclusionThe high levels and health risk estimates of PTEs in the sachet water samples suggested unsafe for consumption. Periodic monitoring of PTEs in sachet water from the study area is recommended.