Biological Monitoring of Urinary Fluoride Among Phosphate Fertiliser Production Industrial Workers

Abstract

Objectives: Fluoride pollution at the workplace environment arises mostly due to anthropogenic activities. The workers working in phosphate fertilizer industry might have chronic exposure to excessive fluoride which can cause adverse health effects. Therefore, the present study was designed to assess urinary fluoride levels in occupationally exposed workers. Methods: In this study, pre and post-shift urinary samples were collected from phosphate fertilizer industry male workers (n=53). Fluoride levels in urine samples were analysed using an Ion Selective Electrode (ISE). Findings: The mean concentration of pre-shift and post-shift urinary fluoride levels were 2.141.35 and 2.422.02 mg/g of urinary creatinine respectively. Workers’ pre-shift mean urine fluoride levels were categorised according to their working departments. Workers from the manufacture plat of Single Super Phosphate (SSP), Granular Single Super Phosphate (GSSP), maintenance, and administration had fluoride levels of 2.871.88, 2.431.01, 2.161.30, and 0.920.601 mg/g of urine creatinine, respectively. Similarly, the post-shift urinary fluoride levels were 3.683.00, 2.641.85, 2.241.78 and 1.140.53 mg/g of urinary creatinine in these departments respectively. One-way analysis of variance shown significant difference in urine fluoride concentrations between pre-shift (ANOVA, df=3, F=4.717; p=0.006) and post-shift samples (ANOVA, df=3, F=2.895; p=0.044). About 22.64 % of subjects in the pre-shift and 3.77% of subjects in the post-shift had exceeded the urinary fluoride limits prescribed by various statutory agencies. Novelty: Based on pre-shift and post-shift work exposure assessments, this study adds new knowledge to scientific research on the fluoride exposure among phosphate fertiliser sector workers. While there is sporadic information on fluoride levels among various other occupational groups, very few reports reported the fluoride levels in fertilizer industryworkers. Outcomes of this study will help to identify the source of fluoride and extent of fluoride exposure so as to suggest the mitigation measure to control fluoride exposure at occupational settings. Keywords: Biological monitoring; Fluoride exposure; Urinary fluoride; Occupational fluoride exposure; Fertilizer industry workers