Assessment of Fluoride in drinking water and its correlation with different physicochemical parameters in the selected areas of Quetta, Pakistan

Abstract

Fluoride is found naturally in water, soil, plants, and animals in trace amount. The level of fluoride in drinking water has to be controlled in order to get rid of dental and skeletal fluorosis. A study conducted on children of Quetta city aged 12-year from randomly selected areas showed that dental fluorosis has been found in 63% of children (the data is available) which is a very high percentage. Hence, the focus of this research is mainly to assess the contents of fluoride and its correlation with other physicochemical parameters of drinking water quality in Quetta city. By applying an even sampling plan with the samples distribution taken from tube wells of different sites of Quetta city, where the drinking water quality is known to have been deteriorated. The technique for the analysis of fluoride in groundwater sample is the colorimetric SPADNS method. The study shows that the Concentration of fluoride varies from 0.32 ppm to 3.0 ppm (Hazara town to the western by-pass area of Quetta) as compared with World Health Organization (WHO) guidelines of drinking water for fluoride (i.e., 1.5 ppm). A total number of 13 drinking water samples out of 20 were found unfit for human consumption due to increase in fluoride concentration. The statistical correlation results of drinking water show that solubility of fluoride depends on the level of pH. The salts of, K+, Na+, Ca2+, SO42- and Cl- ions take a major role in attaining the favourable pH for the dissolution of fluoride-containing compounds in drinking water. However, fluoride correlation with other physicochemical parameters has not been studied in drinking water of Quetta city. Therefore, this aspect of research was studied accordingly. Furthermore, it is observed that the prevalence of fluoride-related health problems in the study area is due to high fluoride concentration in drinking water, which is expected from rocks with fluoride-bearing minerals of Quetta valley. On the account of the results, de-fluoridation of the identified sampling sites, and regular monitoring of drinking water is recommended at government level to avert further fluorosis risk.