Quality of "sachet" waters in the Cape Coast municipality of Ghana.

To determine the quality of sachet water samples in the Cape Coast municipality of Ghana, random sampling procedures were used to collect 180 samples from 29 brands produced in the municipality from 1999 to 2004. For any particular year, each tested brand was sampled three times at intervals of not less than 2 weeks (usually monthly) between the months of March to June. Forty-five percent (45%) of the brands subjected to bacteriological examination contained coliform bacteria for one sampling period or another during the period of investigation. The coliform contamination seemed to be more prevalent with some particular brands. Three out of seven brands examined in 2004 also recorded the presence of E. coli. Exceedances were recorded for WHO drinking water quality guidelines for pH (6.25-7.93) in 2002 and for conductivity (67-306 microS cm(-1)) in 2002 and 2004. Total hardness values for all sachet water brands were less than 100 mg/l CaCO(3) and therefore below the WHO limit for potable water. None of the samples seems to pose any health dangers as far as the major cations; sodium (17.4-19.1 mg/l), potassium (5.7-6.2 mg/l), calcium (8.0-24.0 mg/l) and magnesium (19.9-50 mg/l) are concern. Apart from nitrite, for which some exceedances were recorded and phosphate which does not have an established WHO guideline, the measured major anions (i.e., chloride: 1.57-37.7 mg/l, sulfate: 0.33-44.33 mg/l and nitrates: 0.005-0.70 mg/l) were within the WHO drinking water guideline. No exceedances were also recorded for iron and lead. In general, the high quality claimed for sachet waters could not be confirmed based on the measured physico-chemical and bacteriological properties. The variable quality and in some cases, poor water quality observed, likely reflects the fact that the sachets are not always bagged under scrutinized sanitary conditions.