Physical, chemical and microbial analysis of bottled drinking water

Introduction People rely on the quality of the bottled drinking water, expecting it to be free of microbial contamination and health hazards. Objectives To evaluate the quality of bottled drinking water sold in Jaffna peninsula by analysing the physical, chemical and microbial contents and comparing with the recommended Sri Lankan Standard (SLS) values. Methods All bottled water samples sold in Jaffna peninsula were collected. Electrical conductivity, total dissolved solid, pH, calcium, nitrate, total aerobic and anaerobic count, coliform bacterial count and faecal contamination were checked. Results These are 22 brands of bottled drinking water sold in Jaffna peninsula. The sample had very low electrical conductivity when compared with SLS (750 mu S/cm) and varied from 19 to 253 mu S/cm with the mean of 80.53 (+/- 60.92) mu S/cm. The pH values of the bottled drinking water brands varied from 4.11 to 7.58 with a mean of 6.2 (+/- 0.75). The total dissolved solid content of the bottled drinking water brands varied from 9 to 123.67 mg/l with a mean of 39.5 (+/- 30.23) mg/l. The calcium content of the bottled drinking water brands varied from 6.48 to 83.77 mg/l with a mean of 49.9 (+/- 25.09) mg/l. The nitrate content of the bottled drinking water brands varied from 0.21 to 4.19 mg/l with the mean of 1.26 (+/- 1.08) mg/l. Aerobic bacterial count varied from 0 to 800 colony forming unit per ml (cfu/ml) with a mean of 262.6 (+/- 327.50) cfu/ml. Among the 22 drinking bottled water brands 14 and 9% of bottled drinking water brands showed fungal and coliform bacterial contaminants respectively. The water brands which contained faecal contamination had either Escherichia coli or Klebsiella spp. Conclusions The bottled drinking water available for sale do not meet the standards stipulated by SLS.