Concentration of heavy metals and major elements in shallow well water and its relation with the evidence of oral and esophagus cancers in Namom District, Songkhla Province

Altogether 39 water samples were collected from shallow wells in Namom district, Songkhla province. Two groups of sampling wells were recognized, i.e., a cancer related group and a no-cancer related group, which were related with the presence or absence of evidence of oral or esophagus cancers at the home of well owner. The pH, TDS, hardness and concentration of heavy metals and major elements (Ba, Cr, Mn, Fe, Ni, Cu, Cd, Zn, Pb, Mg and Ca) of water samples were measured. The results showed that the pH of all water samples ranged from 4.5 to 7.4 among which 64.1% of water samples were not complied with the rural drinking water quality criteria B.E. 2531. Heavy metal and major element concentrations in all samples did not comply with the quality criteria except for cadmium in 1 sample (0.0055 mg/l) and iron in 2 samples (0.77 and 0.59 mg/l). Results of multivariate factor analysis showed that three factors were extracted from 9 variables. Factor-1 included TDS, hardness, Mg and Ca, which were interpreted as a result of granite decomposition. Factor-2 included the concentrations of Ba and Zn, which originated from decomposed granite in the south of Krongrang and Tungkamin sub-districts before transporting towards the north into the Klong-Wa. Factor-3 included a single element, iron, which had no relation with any others. Results of the t-test revealed significant differences (p