Pesticides and Farmers’ Health

Most Thai farmers rely heavily on the use of synthetic pesticides. Although most of them know that these pesticides are dangerous chemicals that can be hazardous to their health they seem to ignore this and handle the chemicals as if they were quite harmless. This has created a very serious problem in rural areas where pesticides are being used.

Farmer mixing chemicals by hand
Farmer mixing chemicals by hand

One of the objectives of the IPM DANIDA Project (2001-2006) was to help farmers reduce the risks of pesticide use. Therefore, the project had invited Ms. Helen Murphy, an epidemiologist specialized in pesticide poisoning, to conduct a training workshop on this issue. The goal of this workshop was to develop trainers who can help farmers survey pesticide use and to become aware of how these pesticides affect health in their own community.

To find out how serious and widespread the problems of pesticide poisoning among farmers are, it is necessary to conduct studies where farmers are directly involved. Helen Murphy has been working with governments and international organizations in the region to develop a participatory approach to collect health information with active involvement of farmer communities. The strength of this approach is that it does not use researchers who extract data from farmers. It is the farmers themselves who collect the information, who analyze the information, and who draw the conclusions.

The advantage of this working methodology is that farmers gain a lot of knowledge and understanding about pesticides in their own community and about the hazards involved. By observing and analyzing their own community they are able to immediately start thinking about how to make improvements on their own farm and thus reduce the risks.

Two working approaches

Earlier work in Thailand and several other countries in South and South-East Asia has led to the development of two different approaches. One approach, called a “cross-sectional survey”, is based on a one-time survey of the situation in a farm community. It gives a snapshot of a short moment in time. It helps the farmers to understand what is going on in their community and understand how and when they are most likely to be contaminated by chemicals. Often this will help them to make decisions that reduce the risks, for example by avoiding the most toxic substances (WHO class Ia and Ib) in favor if less toxic products (class III or IV). Behavioral changes in the farm community can be measured by repeating this cross-sectional survey after a period of time.

But often the farmers get so much interested that they go a step further and want to make a more thorough analysis of their situation, which is the second approach. They realize that a one-time survey does not give a complete picture as pesticide use and the hazards involved are different depending on the cropping seasons. They understand that to get a complete picture it will be necessary to monitor their pesticide use over a period of time. This approach is called “pesticide surveillance” or “pesticide self-reporting”.

For both approaches, “cross-sectional survey” and “pesticide surveillance”, a different training manual has been developed. English and Thai versions of these manuals can be downloaded here.

Cross-sectional surveys in Kanchanaburi and Phitsanulok

During the three-weeks visit by consultant Helen Murphy, the training concentrated on the “cross-sectional surveys”. This training involves a number of steps to help farmers understand which factors contribute to the risks of using pesticides:

1) Which chemicals are being used?

The training process involves identifying the chemicals (active ingredients) and finding out how toxic they are (WHO classification) and to which chemical family they belong (Organophosphates, Carbamates, etc.). Knowing the chemical family is important as each family is characterized by different signs and symptoms of poisoning.

2) How much pesticide is used?

The risks for the farmers are obviously higher when bigger volumes of pesticides are handled. This is calculated for each farmer by calculating the volume per tank, the number of tanks, the frequency of spraying.

3) Observe spraying practices

The participants learn how, when and where most pesticides enter the body. The training takes away the misconception that breathing is the most common way of poisoning. In fact it is through skin contact that most chemicals enter the body.

4) Observe the storage of pesticides and disposal of empty containers

In this step the participants observe and learn how storage and disposal practices form a risk for contaminating food and water, children and farm animals.

5) Recognizing signs and symptoms of poisoning

Participants observe signs and symptoms of poisoning and learn to distinguish pesticide related symptoms from other symptoms. This is accomplished by having farmers explain to each other the difference between sweating due to hard labor and sweating as a result of pesticide poisoning.

The workshop conducted by Helen Murphy first introduced this concept to trainers of DOA, DOAE and Public Health (1st week) who then continued to train a group of vegetable farmers near Kanchanaburi (2nd week) and a group of mango growers near Phitsanulok (3rd week). Both the vegetable and mango growers learned how to conduct the survey in a practical way by observing and interviewing some of their neighbors and analyzing these data.

Following the training, both farmer groups then started to conduct a cross-sectional survey in their own community. Each trained farmer observed and interviewed 2 or 3 of his neighboring farmers. After collecting the information, they met again several times to discuss and analyze the data and to plan a meeting to give feedback to members of their own community. The data collected by these farmers are presented in the following pages:

Participants in the training talk with a farmer.
Participants in the training talk with a farmer about his pesticide use.


Identify pesticides
An exercise during the training to identify the active ingredients of pesticides.


Helen shows skin symptoms
Helen Murphy shows pictures of symptoms of pesticide poisoning.

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