Introduction Pesticides are widely used by farmers in Malaysia but there is limited information on exposures experienced.

Objective To determine Malaysian farmer’s exposure from pesticide spray events through the collection and analysis of urine samples.

Method 25 farmers growing either rice (n=16) or vegetables/fruits (n=7) from the east coast of Malaysia provided two urine samples, one in the morning before they started spraying and the other in the evening of the first day of spraying either with chlorpyrifos (n=16), cypermethrin (n=18) or pyrethroids (n=21). Urinary levels of 3,5,6-Trichloro-2-pyridinol (TCPy), 3-phenoxybenzoic acid (3PBA), and total 2,2,dimethylcyclopropane carboxylic acid (DCVA) were determined by liquid chromatography-mass spectrometry and corrected for urinary creatinine levels.

Results Farmers who used the precursor pesticide had higher levels of urinary metabolites after spraying than those who did not. Urinary TCPy levels of chlorpyrifos applicators were significantly higher post-spraying compared to pre-spraying: median levels and interquartile range (IQR) were 94 (18.6–228.4) versus 43 (18.8–121.5) µmol/mole creatinine respectively (p urinary 3PBA levels of pyrethroid users (n=21) were also significantly higher post-spraying than pre-spraying: median levels (IQR) were 1.8 (0.6–3.7) versus 0.9 (0.5–1.7) µmol/mole creatinine (p Urinary DCVA levels of cypermethrin users (n=18) were significantly higher post-spraying than pre-spraying : median levels (IQR) were 5.6 (2.3–10.3) versus 1.9 (1.4–4.2) µmol/mole creatinine (p Pre-spraying urinary TCPy (but not 3PBA or DCVA) levels in farmers who had applied the precursor pesticide were higher than pre-spray levels in farmers who had not (p<0.01).

Conclusion Current use of pesticides by Malay farmers results in increased exposure that can be detected by urinary metabolite measurement. This suggests further training is needed to reduce exposure in this population.