Abstract:
Glyphosate (GLY) is a non-selective weedicide widely used by vegetable farmers in Nuwara
Eliya (NE), Sri Lanka. It has been recently declared as carcinogenic and induces nephrotoxicity
in rat models. Poor weedicide handling and management are common among farmers and it
may increase the risks of exposure to the weedicides. Therefore we conducted a survey to find
out the herbicide usage and handling practices of vegetable farmers (n=98) in selected locations
in NE. [Bulluala, (n=24); Hawa eliya, (n=37); Sandathanna, (n=37)]. The survey was
conducted by using the questionnaire which contained demographic information and agro
chemical survey. Based on the survey, we estimated GLY exposure among selected vegetable
farmers who have been exposed more than 10 years [Sandathanne, (n=11); Bullualla, (n=5);
Hawa eliya, (n=14] and compare with non-farming population (n=20) from Matara. Early
morning first urine sample was collected and GLY concentrations in urine (U-GLY) were
analyzed using competitive enzyme-linked immunosorbent assay (ELISA) method using
commercial kits (US Biocontract Inc., San Diego, CA, LDD-0.05 ppb).Urinary creatinine was
measured using the Dimension® clinical chemistry system (Siemens Healthcare Diagnostics).
U-GLY concentrations were determined by 4PL nonlinear regression model and differences of
U-GLY and creatinine adjusted U-GLY among the locations were compared by IBM statistics
19. U-GLY was detected in all study groups and the highest mean concentration of U-GLY
was detected in Bulluala vegetable farmers (234.67µg/g Cr, Min=175.7, Max=284.5) and
lowest concentration of U-GLY was detected in Sadathanna vegetable farmers (176.54µg/g Cr,
min=140.91, max= 205.38). These results are compatible with the survey results of weedicide
handling and management. U-GLY concentrations in vegetable farmers were significantly
higher than the non-farming control group (P< 0.05) indicating higher occupational exposure
among the farmers. However GLY residues were also detected in the control group (Mean =
136.31 µg/g Cr) and such non occupational exposure warrants further studies.