A Study on Water Purityusing Electrical Conductivity

Abstract

Rain water quality was assessed by the use of an electrical conductivity and its

reciprocalresistivity properties of water. Water itself is not a good conductor of electricity ;it is the dissolved impurities which will conduct a current. The theoretical ultra-pure water has a conductivity of 0.05 microsecond/centimeter. The microorganisms,pH and an electrical conductivity of the rain water from inner area of Bangkok city(ChulalongkornUniversity campus) were determined during the rainy season in the year 1992, 1993 and 1994 A.O. The rain water sample in 1993 showed a higerelectrical conductivity among the rain water samples of the other years (P<0.001 ). The colonies of micro-organisms were seen in- the culture plates of allrain water samples. Each of the rain water samples were slightly acid ;the highest acidity was observed from the rain water sample of the year 1992 (P<O. 001 ). The rain water collected from the heavy traffic area is not only contaminated with microorganisms but also shown to be an acid rain. It is suggested, therefore, that this kind of rain water should not use for drinking.