Evaluation of chemicals of potential concern and enzyme activity in stored sachet water produced in diobu Port Harcourt, Southern Nigeria

This study investigated water quality and the effect of prolonged storage on selected brands of sachet water produced in Diobu Port Harcourt, Southern Nigeria by estimating the levels of chemicals of potential concern (COPCs) and enzyme activity in the water samples. Five different brands of sachet water purchased from water factories in Diobu were labeled WS 1 - 5 and assessed for COPCs, toxic metals, physicochemical parameters and enzyme activity, following standard procedures. Results were compared with World Health Organization (WHO) standards for drinking water. Biochemical Oxygen Demand (BOD) in all five brands of sachet water ranged between 2.00±0.00mg/l and 17.51±0.14mg/l, indicating non-compliance with WHO permissible limits for BOD in drinking water. Similarly, Chemical Oxygen Demand (COD) showed exceedances in WS-5 when compared with regulatory standards, and ranged from 102.70 ± 0.67mg/l at day 0 to 207.30 ± 0.33 mg/l at day 7. WS-2 and WS-5 showed turbidity values above recommended limits at days 0, 7 and 14. Other physicochemical parameters analyzed were within WHO permissible limits. Also, values obtained for some COPCs and heavy metals were all within WHO guidelines for water potability. Assay for acid phosphatase, alkaline phosphatase and amylase enzymes in the water samples showed increasing enzyme activity between days 0 and 14. Overall, our results showed significant presence of microbial pollutants, progressive increase in enzyme activity and leaching of dichloromethane with prolonged storage of sachet water under direct sunlight. These findings indicate that the stored sachet water brands are not healthy for human consumption.