Nitrate and fluoride content in ground water in the Batticaloa district

Abstract

A preliminary investigation was done to determine the nitrate and the fluoride content in ground water in the Batticaloa district. Thirty-three wells have been selected from eight Divisional Secretary (DS) areas in this district and sixty-six samples were collected. Nitrate and fluoride content in these samples were analysed using nitrate and fluoride ion selective electrodes respectively. The lowest nitrate content was observed at hambalawatta as 1.49 mg/dm3 and highest nitrate content was observed at Mandur as 96.60 mg/dm3. This analysis showed that 85% of these wells contain nitrate concentrations considered to be safe by WHO standard (< 45 mg/dm3) and 15% of the wells had nitrate content of greater than 45 mg/dm3. Therefore appropriate technologies for agriculture, sewage disposal and construction of soakage pits should be innovated to reduce the nitrate pollution. The study also revealed that the well water at Vantharumoolai contained the minimum amount of fluoride (0.029 mg/dm3) meanwhile the well water at Aiyithiyamalai contained the maximum amount of fluoride (0.685 mg/dm3). Only 18% of wells contain fluoride concentrations considered to be safe by WHO (0.5 — 1.5 mg/dm3). Therefore some preventive measures such as fluoridation of ground water are necessary to protect the ground water quality.