1. Pesticide Poisoning of Farm Workers: Implications of Blood Test Results from Vietnam
Susmita Dasgupta, Craig Meisner, David Wheeler, Nhan Thi Lam, Khuc Xuyen
The World Bank and The National Institute of Occupational and Environmental Health, Vietnam

2. Pesticide consumption (metric tons) in Vietnam
Source: FAO, 2004
Pesticide consumption has more than doubled in the past decade

3. Alarming Composition/Application of Pesticides
In 2000, a nation-wide survey by PPD found:
2,500 kg of banned pesticides (Methamidophos, DDT and others).
4,753 litres and 5,645 kg of illegally imported/ counterfeit pesticides.
In 2000, another survey in the South found:
96.6% of the farmers over-use pesticides
95% of the farmers pour residual spray into canals/ ditches/ re-apply it on other plants/ over-apply it to the same crop to get rid of it.

4. Vietnam has limited secondary data on Health Effects of pesticides
Questions of Interest:
What is the incidence of pesticide intoxication?
Are self-reported data good indicators of actual intoxication?
What are the determinants of pesticide intoxication?
Methodology:
Survey of Rice Farmers (pesticide applicators) in Mekong delta.
Clinical Exam
Blood Test

5. Application of pesticides: survey evidence

6. Health Effects of Organophosphates and Carbamates cited in Medical Literature
Acute:
Mild headaches
Flu-like symptoms
Skin rashes
Blurred vision
Other neurological disorders
Chronic:
Cardiopulmonary problems
Neurological and hematological symptoms
Adverse dermal effects

7. Blood Test for the Detection of Acute and Chronic Pesticide Poisoning
Cholinesterase Enzyme (AchE)Test: (poisoning from organophosphates and carbamates)
Low Acute Poisoning: Reduction of numerical value of AchE in red cells and in plasma >25%
High Acute Poisoning: Reduction of numerical value of AchE in red cells and in plasma >33%
Chronic Poisoning: Reduction of numerical value of AchE in red cells >66%

8. Specific Health Effects found in the Survey
98% of the farmers in the survey reported health problems
88% of the respondents experienced multiple health effects, with the maximum number of ailments as nine

9. Blood (Cholinesterase Enzyme) Test Results

10. Self-reported symptoms are not reliable indicators of actual pesticide poisoning
(Correlation between each individual symptom and blood test results were conducted. The highest correlation found was 0.17)

11. Determinants of Cholinesterase Enzyme Inhibition: Regression Analysis

12. Determinants of Cholinesterase Enzyme Inhibition: Regression Results
Farmers applying more hazardous pesticides (WHO Ia & Ib) are more likely to suffer
Incidence of pesticide poisoning can be significantly reduced by suitable averting behavior
Pesticide poisoning in Vietnam revealed strong provincial pattern. This raises the concern that the environment in certain regions may have been contaminated from prolonged exposure to toxic pesticides

13. Summary and Conclusions
Health effects of organophosphates and carbamates is serious in Mekong Delta, Vietnam
Self-reported symptoms have very weak associations with actual poisoning
Suitable averting behavior while handling pesticides should be advocated
Significant provincial differences in poisoning incidence implies that pesticide contamination may be pervasive in certain areas
Tests of pesticide residues in surface/ground water and soil is necessary