Groundwater fluoride in Sri Lanka: opportunities to mitigate the risk at maximum contaminant level

Introduction: High groundwater fluoride (F) is one of the major environmental hazards in the dry zone of Sri Lanka. The prolonged exposure to F at maximum contaminant levels can give rise to lifelong debility and disability among its inhabitants. Objectives: This study investigated the F contamination in groundwater resources in Sri Lanka above recommended Maximum Contaminant Levels (MCL) and possibilities to mitigate the health risk. Methods: Groundwater samples (6107) were randomly collected from different geographic areas of the country, and categorised as hazardous, if it exceeded the maximum contaminant level of 4 mg/L (the level at which bone health is compromised). The minimum distances from a hazardous to a relatively safe F groundwater source (below 1.0 mg/L and 1.5 mg/L) were determined using geospatial analysis. Results: Only 2.3% (142) of the total sample was found to be hazardous to skeletal health. Optimal F sources were identified in close proximity to highly contaminated sources (>4.0 mg/L), some even within a walking distance of 500 metres. Conclusions: The identification and elimination of maximally contaminated sources, possibly by dilution with widely available low F sources in close proximity, would be a more feasible and cost effective approach to ensure long term public health benefits.

Infrared spectroscopic analysis of staghorn calculi obtained after open renal surgery in a urology unit of Sri Lanka.

The composition of renal stones varies widely among populations. The aim of our study was to determine the composition of staghorn renal stones using Fourier transform infrared (FTIR) spectroscopy in a cohort of Sri Lankan patients. Forty two staghorn calculi removed from kidneys of adult patients during open surgery were analysed. There were 32 men. Nineteen (45%) were calcium oxalate monohydrate (whewellite) stones. Stones containing a mixture of calcium oxalate and calcium hydroxyl phosphate (apatite) were found in 16 (38%). Only 4 (10%) staghorn calculi were coposed of struvite. Three (7%) were uric acid stones. So most staghorn renal stones in Sri Lanka are calcium oxalate. Contrary to the traditional view based on studies done in the western world, only 10% of staghorn calculi removed from patients in Sri Lanka are struvite or infection stones. This could be the reason for kidneys with staghorn calculi in Sri Lanka to retain their function.