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Dangerous pesticide use in Central America - Wanted: a new approach 

Excellent local data on pesticide imports and impacts is available in Costa Rica and other Central American countries, and pioneering work on organic agriculture has been initiated. Yet pesticide use is increasing and regulation is poor. A health programme to promote pesticide poisoning surveillance systems has yielded disappointing results. Catharina Wesseling recommends a multi-stakeholder approach to address the problems.

A farmer filling his backpack by scooping a pesticide mixture out of the drum, Tierra Blanca de Cartago, July 2000. Photo Catharina Wesseling.

In Central America many thousands of tonnes of pesticides with high acute and chronic toxicity have been used for decades. In Europe serious efforts to reduce pesticide use have brought encouraging results, particularly in Sweden(1), where pesticide use has been reduced by approximately 70% over 10 years. In Central America, on the other hand, the overall pesticide use was higher in 1999(2) than the average annual pesticide consumption between 1980-1989(3) (Figure 1). Many of the most commonly used pesticides continue to be of toxicological concern (Table 1). 
    Hazardous exposures continue despite workers’ improved awareness of the dangers. Studies among small producers and plantation workers in Nicaragua and Costa Rica still observe serious deficiencies in pesticide handling and the effectiveness of personal protective equipment(4,5,6,7). Occupational low-level exposures to paraquat may still occasionally result in fatal poisoning(8). These studies are evidence that the obstacles to reducing pesticide risks to acceptable levels are difficult or impossible to overcome in developing countries. 

Acute poisonings
In 1998, almost 6000 pesticide poisonings were reported to surveillance systems of five of the seven Central American countries(9). An estimate, which took into account under-reporting, arrived at 30,000 pesticide poisonings annually in the region(10). Reported occupational poisonings appear to have declined during the 1990s in Costa Rica(11) and numbers in Nicaragua dropped during 1999(12), but these trends could reflect either better working practices or deteriorating reporting. Poisoning epidemics and surveys have identified specific dangerous pesticides widely used in Central America, in particular paraquat, carbofuran, terbufos, methomyl, methamidophos, methyl-parathion, and aluminum phosphide(13,14,15,16).

Chronic effects 
Chronic or long-term health effects are often associated with less acutely toxic pesticides, which are commonly used but do not appear in the poisoning statistics. Chlorothalonil has been identified as a risk factor for ashy dermatitis among banana plantation workers in Panama(17). Male banana workers, who are highly exposed to pesticides, are at increased risks for penile cancer, melanoma and lung cancer, and female banana workers for cervical cancer and leukemia(18). Cancer risk in populations of rural counties with high pesticide use tends to be higher than in rural areas with low pesticide use, in particular lung cancer in men and women and female hormone related cancers(19). Genotoxic effects have been observed among women workers of banana packing plants(20) and among male field workers(21). An association between long-term paraquat exposure and respiratory symptoms was found in Nicaragua(22). Persistent damage in the central and peripheral nervous systems have been demonstrated in workers previously poisoned with cholinesterase inhibiting pesticides in Nicaragua and Costa Rica(23,24,25,26,27). Neurotoxic effects were also observed among DDT-exposed vector control sprayers in Costa Rica(28).

Table 1. Selected pesticides of special toxicological concern which were among the ten most imported in one or more of seven Central American countries in 2000

Top-ten pesticide 
(No. countries)

Toxicological concerns 
Paraquat  Fatal occupational and accidental poisonings, dermal and eye lesions, suicides 
Mancozeb  Cancer, toxicity for the thyroid gland, dermatitis, neurotoxicity
Terbufos  Fatal occupational poisonings (WHO Ia)
Methamidophos  Acute poisonings (WHO Ib), delayed peripheral neurotoxicity
Methyl bromide  Acute poisonings (WHO Ib), neurotoxicity
Aluminum phosphide  Acute poisonings, suicides
Carbofuran  Acute poisonings (WHO Ib)
Methyl-parathion  Acute poisonings (WHO Ia)
Copper arsenate  Cancer
Aldicarb  Acute poisonings (WHO Ia), immunotoxicity 
The seven countries are Belize, Costa Rica, El Salvador, Honduras, Nicaragua, Panama (1999 figures), Guatemala (1998 figures). Source: Data compiled by IRET.

A stakeholder strategy – potential in Costa Rica
All the main actors in the pesticide arena need to work together to reduce these adverse effects. Taking the example of Costa Rica, there is significant potential for reducing pesticide hazards if the resources of the diverse but concerned stakeholders could be galvanized.

Pressure from workers for improved working conditions or reduction of pesticide risks has been limited. Under Costa Rican law, workplaces with more than ten workers must have an occupational health committee with worker participation. In practice this does not function and when it does, workers usually lack training to address the problems effectively. Workers accept risky conditions as a part of the job and of life. 
    Trade unions recognize that occupational health and safety is a neglected field(29). Several NGOs carry out training, and advocate workers’ rights. Some workers’ organizations claim compensation for harmful effects, e.g. banana workers who became sterile after exposure to the nematicide DBCP (dibromochloropropane), the wives of DBCP victims (many themselves banana workers), and vector control workers who were exposed to DDT. 
    Foro Emaus – a coalition of trade unions, farmers, community and environmental organizations, religious groups and university students – was established in 1992 and has worked to improve the conditions of banana plantation workers, gaining national and international prestige. 

In Costa Rica the Ministry of Health is legally responsible for pesticide approvals. However the registration of pesticides, the core of regulation, is handled at the Ministry of Agriculture. Regulations are commonly based on international guidelines or US actions, without consideration of local conditions. Recent deregulation in pesticide registration is a further set back. 
    Short-term economic interests strongly influence policies. The interests of producers of export commodities and the pesticide industry have prevailed over public health concerns. For example a Ministry of Health programme funded by a banana tax has been substantially weakened. Imports of the ozone-depleting methyl bromide skyrocketed in a decade to almost a million kilograms per year. Exonerating import taxes on pesticides favors the pesticide industry(30).
    Positive, but undeveloped, initiatives at the Ministry of Agriculture have been programmes for organic agriculture, and use of sustainable development indicators, such as kilograms of pesticide used per hectare. The Ministry of Labor and the National Council of Occupational Health have been weak actors, but have prepared an ambitious plan to increase occupational health activities. 

Academic sector
The main objective of the academic sector in Costa Rica and Nicaragua(31) has been to produce exposure and health effect data, and to transfer this information to relevant local, national and international sectors. To date, however, national policy makers have made no specific regulatory decision based on local data. 
    Universities have played an important role in investigating alternative technologies and distributing details to agricultural target groups, often through participatory research methods. In the early 1990s, universities in Costa Rica carried out pioneer organic agriculture projects and in Nicaragua Integrated Pest Management (IPM) programmes. Central American universities collaborate in the search for alternatives, including methyl bromide. Economic academic sectors increasingly integrate human health in development policies and generate qualitative and quantitative data on costs and benefits of pesticides. They point out the benefits of organic agriculture in terms of selling to environmentally conscious markets, while reducing occupational and environmental health risks.

Figure 1. Millions of kilograms of pesticides imported in Central America

Independent farmers do not take health precautions for themselves or their employees. In cooperatives, pesticide safety training sessions are occasionally organized. A study in Nicaragua has found that some farmers, even small-scale farmers, hire the services of others to apply pesticides to avoid risks(32). 
    Many agricultural workers in Central America work on large agricultural enterprises growing tropical fruits, ornamental plants and other crops. Such companies often have occupational health departments, and many are trying to achieve ISO-14000 or similar certifications promoting social and environmental justice. Freedom of association and certain safety conditions, particularly in relation to pesticides, are among the requirements. However, these are emphasized less than the environmental standards. 

Pesticide industry
Marketing strategies are aggressive, but camouflaged under the umbrella of responsible stewardship and terms like ‘IPM’ and ‘sustainable development’. Pesticide manufacturers and distributors have strong representation in inter-institutional commissions, including pesticide registration boards, where conflicts of interest are clear. The resources for lobbying are unlimited compared to those of other stakeholders. 
    In Costa Rica, alliances between government and the pesticide industry include a project on environmental and agricultural education on the risks and benefits of pesticides and safe pesticide management. This aims at target groups from agricultural workers, pesticide vendors and medical personnel, to schoolchildren, teachers and housewives. The Ministry of Health and Zeneca signed an official agreement to train users of Gramoxone (paraquat) in the benefits and safe use of this herbicide. But an earlier public announcement of the Minister of Health (at the 1998 International Conference on Pesticide Use in Developing Countries: Impact on Health and Environment), that paraquat would be severely restricted was never implemented. 

International organisations
International programmes or strategies to control pesticide use are recognised by all Central American governments. Harmonization efforts on labelling, and other pesticide control measures attract large resources, whereas the benefits for workers’ health are slow and often negligible. 
    Since 1993, the project PLAGSALUD [see PN51 pp5-6] (coordinated by the Pan American Health Organization and sponsored by DANIDA, the Danish International Development Agency) has supported ministries of health to set up pesticide poisoning surveillance systems and improve capacity to gather local data(33). In most countries, the project leaders view the results as promising. In Costa Rica, where the potential should be greatest, the results are frankly disappointing and the causes for such an expensive failure should be carefully evaluated. 
    During the 1990s, ‘Fair Trade’ movements have emerged, which help small producers to get a share on the international market and improve their living conditions. Some organisations certify plantations if they comply with agreed standards. 

Lack of achievement
Pesticide use has not diminished and toxicity of the most commonly used pesticides has not reduced over 10 or 20 years. Acute poisoning appears to have reduced, but surveillance data are not reliable enough to be conclusive, and poisonings are by no means a problem of the past. Chronic and long-term health effects from past pesticide use are apparent, while high exposure continues and future effects can be expected. 
    The complexity of risk assessment exceeds the capacity of the Central American governments. Regulations are not based on local facts. Despite the abundance of hard data on exposure and effects of paraquat, the herbicide remains among the most imported pesticides in all Central American countries. Workers’ participation in occupational safety and health is weak, and the industry has a disproportionate influence on decision-making.

Future strategies
Pesticides are a hazardous technology when used under conditions that cannot guarantee a minimum of safety, and they have deleterious effects on the workers’ health. This is incompatible with principles of sustainable development. Decades of strategies focusing on ‘safe pesticide management’ have failed to bring about improvements, and the most effective way to reduce risks in developing countries is to reduce and eventually eliminate pesticide use. The following strategies should be considered: 

  • Multidisciplinary approaches that aim at progressive reduction and elimination of pesticide use, based on trust between researchers, workers and planners in agriculture, health and economic development. 
  • Strategies to promote locally appropriate alternative technologies.
  • Government agencies should draw on the research capacities of universities, using their local data. 
  • Workers’ right-to-know and empowerment should be supported. 
  • Academic sectors should support workers, high-risk communities and the public with sound information and provide tools for meaningful participation in decision-making. 
  • The role of industry should be limited to the development of less toxic and safer products and responsible marketing. 

Catharina Wesseling is a researcher at the Central American Institute for Studies on Toxic Substances (IRET), Universidad Nacional, Heredia, Costa Rica, Email:

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[This article first appeared in Pesticides News No. 54, December 2001, pages 12-14]

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