Evaluation of Changes in Some Physico-Chemical Properties of Bottled Water Exposed to Sunlight in Bauchi, Nigeria

Abstract

Abstract. It is common for bottled water and other assorted drinks to be seen displayed outside stores and in the sun in most parts of Nigeria. The country is mostly hot year-round and over the course of the year temperatures can rise to as high as 40 °C around March–April in the study area. The leaching effect of chemicals from polyethylene terephthalate (PET) bottled water was investigated for five (5) commercially available bottled water brands. Temperature, pH, Antimony, Bisphenol A and Nitrate levels were measured on day zero, 14 and 28 for control samples and samples exposed to direct sunlight, using destructive sampling technique. The study found that pH for brands B and D were lower than the Nigerian Standard for Drinking Water Quality (NSDWQ) and United States Environmental Protection Agency (US EPA) regulations at day zero. The control sample for Brand A maintained pH within the guideline values for 0–28 days while all Brands exposed to sunlight for 14 and 28 days had lower values than specified. Antimony was not detected in brands A, B and E in the baseline measurement at day zero while brands C and D had low values; after 28 days all the control samples still had Antimony levels within the US EPA standard. Meanwhile all the samples exposed to sunlight exceeded US EPA standard levels at 14 and 28days except brand A which was within limit at 14 days with value of 4.59 µg/L. All control and exposed samples were below the European Union Drinking Water Directive (EU DWD) total daily intake (TDI) of Bisphenol A (0.05 mg/kg body weight/day). Values obtained for Nitrate showed that all control samples did not exceed the US EPA guideline level for Nitrates in drinking water for 0, 14 ad 28 days while three (3) of the samples, Brands C, D and E, exceeded the guideline level at 28 days. Expose of bottled water to sunlight was seen to impair the quality of the water for consumption. It is recommended that regulators and practitioners drive implementation of proper storage/retailing of bottled water products and improve legislation on manufacture of plastics for food contact products.