Brazil ranks among the top five tobacco growing countries in the world, producing more than 600,000 tons in 1997, 7% of the global tobacco crop. The vast majority of land used for tobacco production is situated in the southern states of Paraná, Santa Catharina and Rio Grande do Sul. On average pesticide application approaches a hefty 30kg per hectare per year. In dry years these levels increase and can reach as much as 100 kg. Many pesticides used in tobacco cultivation are highly toxic and their use is increasing.
Most tobacco is cultivated on an estimated 150,000 small independent family farms of about 2.3 ha. Production is very labour-intensive, resulting in all family members, including small children working in the field. Approximately 750,000 men, women and children work on these farms.
In recent years, scientists, non-governmental organisations and other Brazilian action groups have drawn attention to the plight of the tobacco farmers. Studies have illustrated:
poor social-economic levels
a dependency on the powerful cigarette industries and leaf exporters
health problems from exposure to pesticides
elevated levels of depression and suicide
After finding high rates of depression and suicides among tobacco workers, field workers from the Dutch development agency Global Ministries launched a four-month pilot study to assess the possibility of a causal relationship between the use of certain tobacco pesticides and depression.
High suicide rates are common among farmers in many countries. In the tobacco states of Rio Grande do Sul and Paraná, average suicide rates were 8.09 and 5.25 per 100,000 inhabitants in 1989. The average suicide rate in Brazil is 3.20.
Many social and psychiatric factors can play a role in suicide cases. Poverty, instability, constant stress, marital problems, psychiatric and physical illness, alcohol and drug abuse can all lead people towards suicide. The easy availability of toxic substances and the publicity given to suicide cases can also play a role in elevating suicide rates.
Pesticides as a cause of depression
The anticholinesterase pesticides (organo-phosphates and the carbamates) are considered most likely to cause depression and suicide among operators.
A number of epidemiological studies have been carried out on exposed groups, such as sprayers in malaria control programmes, farmers in general, banana workers or forestry workers. The studies have raised suspicion that there may be a causal relationship between high-level acute exposure to OPs, and possibly organochlorines and carbamates and depression. The studies do not show evidence of a causal relationship between depression and chronic exposure.
No threshold limits have been established to indicate levels of exposure which would induce depression in Paraná. OPs have been identified as an important risk group, although no proper risk assessment can be carried out.
The following pesticides were identified as requiring further study:
Sevin 7,5 and Carvin (carbaryl), Acefate Fersol 750 PS, and Orthene 750 BR (acephate), Doser, Confidor 7000 GRDA (imidachloprid), Lorsban 480 BR (chlorpyrifos), Solvirex (disulfoton), Furadan (carbofuran), Temik (aldicarb), Brometo de Metila (methyl bromide), Dithane PM (maneb), Manzate 800 PM (mancozeb) and Formicida Mirex (sulfluramide).
The researcher recommended minimising the occupational exposure of tobacco farmers to pesticides which are suspected of causing depression and suicide.
(DB)
Natascha Smits, Suicide and depression resulting from exposure to pesticides among tobacco farmers in Paraná, Brazil, Wageningen University, 2000.
[This article first appeared in Pesticides News No. 48, June 2000, page 16]