Bacteriological, physicochemical properties and heavy metals content of plastic bottled water sold in Obio-Akpor Local Government Area, Rivers State, Nigeria

Increase in demand for bottled water by Nigerian population with less emphasis in the quality of the product could impact their health. In this study, quality assessment of fifty-one (51) plastic bottled water randomly sampled from Obio-Akpor Local Government Area (LGA), was carried out. The temperature of the bottled water samples was determined using mercury-in-glass thermometer. The pH, total dissolved solids (TDS), and electrical conductivity (EC) of the samples was analyzed using the Apera PC60 5-in-1 meter. A digital desktop turbidimeter was used to test for turbidity. Microbiological analysis of the samples involved the use of culture media, Gram's staining, biochemical tests, motility test, and most probable number (MPN) method. Atomic Absorption Spectroscopy (AAS) was used to determine the quantity of heavy metals (Pb and Cd) present in the bottled water samples. The temperature, pH, TDS, EC, and turbidity of the samples were within the ranges of 28.0-38.2oC, 5.42-7.74, 0-287 ppm, 2-577 µS/cm, and 0.007-2.582 NTU respectively. The results showed that 4 out of 51 samples of bottled water had a total heterotrophic bacterial count within the range of 6.6 x 102 to 5.4 x 103 CFU/ml, fecal coliforms 8 to >21 coliform bacilli/100 ml, while total coliform bacteria (2 to >27 coliform bacilli/100ml) was encountered in 15 samples. The lowest concentration of Pb and Cd in the samples were below detection limit (BDL), while the highest concentration was 1.43263 and 0.03945 mg/L, respectively. Cadmium and lead content of 16 and 26 samples exceeded the Nigeria Industrial Standard (NIS) permissible limit for drinking water, respectively. On the contrary, the TDS, EC, and turbidity of all the samples of bottled water were within the NIS permissible limit. To protect the health of bottled water consumers, the use of modern water treatment plant, strict implementation of personal hygiene by workers, good manufacturing practices, quality assurance programme, and creating more awareness on proper handling, and effective monitoring of the product quality by relevant regulatory agencies are recommended.