Fatal exposure

Workers exposed to pesticides over a long period of time may run the risk of contracting cancer

 
Published: Wednesday 30 April 1997

a recent study conducted in Hungary with the help of the World Health Organization (who) has found that workers exposed to pesticides showed a considerably higher percentage of abnormal cells than the accepted amount. According to a team headed by I Desi of the department of public health at Albert Szent-Gyorgui University Medical School in Szeged, Hungary, affected cells show far more chromosomes than the normal 46 chromosomes.

Desi stated this recently at a conference on 'Healthy Cities' organised by the department of geography at the Delhi School of Economics. Although the carcinogenic effects of such aberrations has not yet been proved, the study, titled Exposure of the Population By Pesticides, indicates that higher number of chromosomes may play a role in weakening the immune system. This can indirectly lead to tumourogenesis (proliferation of tumours in the body).

The epidemiological investigation was carried out since 1996 on plant protection spray-workers in open fields and glasshouses. To reveal the most susceptible targets of the toxic action, the researchers checked the effects of pesticides on human chromosomes and the nervous system of animals.

The investigations on people working in glasshouses with different categories of chemical pesticides, showed that circumstances there were worse than in the open field, because of strong humidity, high temperature and lack of wind. These workers had more numerical aberration of the chromosomes than field workers.

The effects of organophosphates on the central nervous system was investigated through the help of experimental rats. Some rats were administered small doses of pesticides for a period of 12 weeks. Results showed that the frequency of spontaneous electrical impulse in the brains of the treated rats was much higher than in untreated ones. According to Desi, higher and faster frequencies of the bioelectrical impulses indicate that the nervous system is working on a higher excitation level because of the effect of the incorporated chemical.

Desi explained, as more people are opting out of the agricultural sector in Hungary, less people are producing food for the whole nation. This, he explains, leads to a remarkably high use of pesticides. Estimates show that on an average, five kg of pesticides was applied per hectare during the period between 1980-90. The amount has now come down to three kg.

Desi's study points out that ddt and other organochlorines cause liver injury and jaundice after chronic intoxication. They are less 'acutely toxic' but contaminate the whole environment. "Organophosphates on the other hand, are more 'acutely toxic', but less persistent. They can cause neural disturbances, behavioural and learning disabilities, and problems in the conduction velocity of the peripheral nerves (the rate at which signals are transmitted from the brain to the limbs and vice versa). They attack the immune system of the poisoned persons and also damage their chromosomes," says Desi.

He further stated that massive quantities of such pesticides may even cause suffocation and heart attacks. He cited the example of the most toxic pesticide used in Hungary - the weed killer grammoxone - which suffocates the victim even when 1-2 cubic cm of it is adsorbed through the skin.

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