Blood Cholinesterase Level as Biomarker of Organophosphate and Carbamate Pesticide Exposure Effect among Rice Farmers in Tarnlalord Sub-District, Phimai District, Nakhon Ratchasima Province, Thailand

Abstract

Background: Pesticide has been imported to Thailand for several years including insecticide, herbicide, and others coinciding with the expansion of the country’s agricultural system. Among these chemicals are organophosphate and carbamate the groups of chemicals primarily used in agriculture. Exposure to these pesticides can cause harmful effect on human health. Methods: This study aims to find blood cholinesterase levels of acetyl cholinesterase (AChE) and plasma cholinesterase (PChE) for 3 times in dry-season crops, and to assess health effects of organophosphate and carbamate pesticides exposure among rice farmers (n = 33) in Tarnlalord Sub-District, Phimai District, Nakhon Ratchasima Province, Thailand. The design of this study was a cross-sectional study with questionnaire by face to face interview and blood-tests by Test-mate ChE (Model 400) instruments. Results: The average age (± SD) of the study was 46.0 ± 9.4 years old. The results showed the ChE  levels  in rice  farmers  in  3  times including (1) the first blood collection, 24 hours after application, 72.70% of the farmers were abnormal (2) the second blood collection, 15 days after the first collection, found 48.50% of the farmers were abnormal, and (3) the third blood collection, 30 days after the  first  collection,  found  42.40%  of  them  were  abnormal.  The  activity  of  AChE  and PChE  level  was  assessed  for  3  times.  Differences  showed  a  statistically  significant association  between  within  24  hours  after  first  application  and  15  days  after the first application and 30 days after the first application and previous (24 hours and 15 days after first application) was significantly associated (ANOVA, p<0.05). The farmers reported their adverse health effects related to gastrointestinal system, urinary system, eye, skin, and central nervous system. Additionally, the  AChE  level  within  24  hours  after  first application  was  significantly  associated to eye  symptoms  (Chi-square,  p<0.05). Conclusion: This study showed that after the rice farmers applied pesticides at the beginning, both AChE and PChE levels were abnormal with self-recovery to normal levels by time. The appropriated  self-practices  and  prevention  from  pesticides  exposure  should  be recommended  to  rice  farmer  regarding  proper  use  of  personal  protective  equipment (PPE)  and  pesticides  handling  to  reduce  adverse  health  effects  from  pesticides exposure.