Bioavailability of plastic contaminants and their effects on water.

Bottled water like any drinking water used for human consumption should be safe and wholesome to ensure adequate public health protection. This is due to potential health effects of concern such as endocrine disruption, toxicity teratogenicity, mutagenicity and carcinogenicity. Despite the number of regulatory bodies, publications on bottled water and speculations on its public health significance, many questions remain to be answered. One of the questions is whether the shelf life of bottled water is a cause for concern. This study examined the bioavailability of plastic contaminants and their effects on plastic bottled and sachet water supplies. A total of ten different brands of commercial bottled water were collected in triplicate, three sachet drinking water and three different plastic containers filled with borehole water were collected from different distributors within Benin City metropolis.
All samples were stored at room temperature for four weeks thus mimicking typical conditions in retail outlets, supermarkets and in homes. Analyses were conducted at one week intervals and within days of being purchased. Low heterotrophic bacterial counts below drinking water alert level of >5.0×103 cfu/ml was observed in all brands of bottled water analyzed. The total viable bacterial counts ranged from 1.0×101 - 1.9×102 cfu/ml. Total coliforms (TC), faecal coliforms (FC) and E.coli were not found in all the bottled water samples tested. Yeasts and moulds were also not found in the bottled water samples. The bacteria isolated from the brands of bottled water samples were Bacillus subtilis, Micrococcus sp. and Staphylococcus aureus while the bacteria isolated from sachet water and plastic bottles filled with borehole water samples were Klebsiella sp., Bacillus subtilis., Escherichia coli, Acinetobacter sp., Micrococcus sp., Staphylococcus aureus , Bacillus sp. and Pseudomonas aeruginosa. However, fungi species such as Aspergillus niger, Aspergillus flavus and Saccharomyces cerevisiae were also found in plastic bottles filled with borehole water .
The physicochemical values of the bottled water samples ranged as follow: conductivity (16.30 ± 10.12-19.10 ± 12.26 μs/cm), turbidity ( 0.20 ± 0.09 NTU), pH (6.05 ± 0.72-7.23 ± 0.48), chloride (0.39 ± 0.27 mg/L), total suspended solid (0.00 ± 0.00 mg/L), total hardness (0.25 ± 0.11 mg/L), total alkalinity (3.50 ± 2.84 mg/L) , total dissolved solids (0.00 ± 0.00 mg/L), BOD(0.52± 0.85) and total suspended solid (0.00 ± 0.00 mg/L). There was no significant changes during the period of study for turbidity, pH, TDS, conductivity, and BOD as they did not indicate any potential impact on the aesthetic qualities of the bottled water. However, borehole water filled into plastic bottles had worse bacteriological and physicochemical qualities. Bisphenol A (BPA) congeners were found in plastic bottles filled with bore- hole water, sachet water and bottled water respectively. The concentration of BPA in bottled water (Eva) ranged from 0.000mg/L in week 0 to 0.214mg/L in week 4 and had a higher concentration than sachet water with Vinyl chloride and Methylene chloride having the highest peaks .Bottled plastic water appeared to have slightly better physicochemical qualities than sachet water at the end of four weeks storage period .The plastic bottled water had lower conductivity, turbidity ,hardness and chloride content than sachet water. This study has shown that the bioavailability of BPA components and reduction of biphysical qualities of bottled water appeared to start manifesting at the fourth week of water storage.