Blood cholinesterase activity levels of farmers in winter and hot season of Mae Taeng District, Chiang Mai Province, Thailand

Effectiveness of a Participatory Program on Pesticide Use Behavior and Blood Cholinesterase Levels in Chiang Mai Province, Northern Thailand

This quasiexperimental study was designed to determine the effectiveness of a participatory program on pesticide use behavior and blood cholinesterase levels. The participants were 18–60 years old, living in Thung Satok subdistrict, San Pa Tong District, Chiang Mai Province. Eighty subjects, including 32 farmers and 48 consumers, were recruited to participate in the study voluntarily by a purposive sampling technique. Data concerning each individual's behaviors were collected using questionnaires, and blood cholinesterase levels were obtained from whole blood finger, providing whole blood pre and postexperiment. The data were analyzed using Fishers' exact and paired t-tests, for the problem situations were independently analyzed. The results show that the participatory process made it possible to improve methods for the prevention of the unhealthy effects of pesticides. After participating in the activities, both groups showed significantly higher scores in before and after knowledge (P < 0.05) and a decrease in pesticide contamination in their bodies as a result of the measurement of average cholinesterase which increased significantly (P < 0.001). In conclusion, the participatory program was applied to solve health problems from chemical hazards. The program can raise awareness about chemical toxicity, leading to the modification of the related behavior toward chemicals and reduction of the contamination of chemicals in the body. Therefore, the adoption of participatory processes can effectively solve problems related to chemical hazards that affect health.

Presence and Health Risks of Obsolete and Emerging Pesticides in Paddy Rice and Soil from Thailand and China

Organochlorine (OCPs) and organophosphorus pesticides (OPPs) have been intensively applied in rice paddy field farming to control pest infestation and increase the yield. In this study, we investigated the presence of organochlorine and organophosphorus pesticides in paddy rice and soil from rice plantations in Thailand and China. According to concentration and distribution of OCPs, the most abundant OCPs residues in rice and soil from Thailand and China were dichlorodiphenyltrichloroethane and hexachlorocyclohexanes. The OPPs of methidathion, carbophenothion, chlorpyrifos, and diazinon were common to Thailand and China in both types of samples. The detection frequency of multiple types of these pesticides was greater than 50% of total samples. The relative concentration of some OPPs residues in rice and soil from Thailand and China were significantly different from each other (p < 0.0083), whereas, no significant difference was observed for the relative concentration of OCPs residues in rice and soil from both countries, except for HCHs (p < 0.05). Bioaccumulation factors of OCPs between rice and soil samples indicated that OCPs and OPPs in soil could accumulate in rice. The carcinogenic and non- carcinogenic risks of OCPs and OPPs seem to be in the safe range as recommended by the European Union.

The Pesticide Exposure of People Living in Agricultural Community, Northern Thailand

Background and Aim

Biomarkers of pesticide exposure are generally lacking in communities where agricultural crops are grown. The purpose of this study was to focus on evaluating biomarkers of pesticide exposure in people living in an agricultural area of San Pa Tong District in Chiang Mai Province, northern Thailand.

Materials and Methods

One hundred and twenty-four participants (38 nonfarm workers, 38 rice growers, 31 longan growers, and 17 vegetable growers) from San Pa Tong District gave consent to participate in the study. Pesticide exposure was assessed by determining acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) levels in blood samples using Ellman's method and measuring 6-dialkylphosphate metabolites (DAPs), 3-phenoxybenzoic acid (3-PBA), and glyphosate in urine samples using chromatographic methods.

Results

AChE and BChE activities in the nonfarm worker group had higher level than those in the grower groups. DAPs were detected in almost all urine samples and 3-PBA was detected in 12-45% of each group, while glyphosate was found in 11 – 30% among the three groups of growers but not in nonfarm workers.

Conclusion

In this study, participants living in an agricultural area of San Pa Tong District were exposed to organophosphate, synthetic pyrethroid, and glyphosate through multiple pathways.