Abstract:
Paraquat (1, 1 – dimethyl -4, 4- bipyridylium dichloride) is a contact herbicide,
predominantly used in Sri Lanka. Despite the imposed ban in agriculture sector, Paraquat
usage was seen among sugarcane farmers in Pelawatta compared to vegetable farmers in
Nuwara Eliya. Therefore the level of Paraquat exposure was studied among sugarcane
farmers comparing that with vegetable farmers. Sugarcane farmers [Warunagama GS,
(n=44); Rahathangama GS (n=20)] and vegetable farmers (n=16) were selected based on
pesticide usage and farming practices. Paraquat concentration in urine samples (U-PQ) were
analyzed using competitive enzyme-linked immunosorbent assay (ELISA) method using
commercial kits (US Biocontract Inc., San Diego, CA) and (U-PQ) concentrations were
determined by 4PL nonlinear regression model. Differences of U-PQ and creatinine adjusted
U-PQ among the locations were compared using One-way anova followed by Dunnett’s test
using IBM statistics 22. Measureable levels of urinary-Paraquat (U-PQ) were detected in all
study groups. Highest concentrations of U-PQ were detected in Warunagama sugarcane
farmers (mean, 3.25 ± 0.29µg/g Cr) and lowest concentrations of U-PQ were detected in
urine samples of Nuwara Eliya vegetable farmers (mean, 0.603 ± 0.03 µg/g Cr). Urine
samples of Warunagama sugarcane farmers recorded significantly higher levels of U-PQ
compared to the control group and Nuwara Eliya vegetable farmers (P< 0.001), indicated
continuous usage of Paraquat by sugarcane farmers (Warunagama). But U-PQ concentrations
in sugarcane farmers in Rahathangama were not significantly different from the control group
and Nuwara Eliya vegetable farmers (P> 0.05). As measurable levels of U-PQ was detected
in urine samples of all study groups non-occupational exposure by Paraquat was evident
which warrants further studies and remedial measures.
