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January 15th, 2016 /

thumb.aspxby Dr. Jared Bakuza, Dar es Salaam University College of Education, Tanzania


Coffee is grown in several parts of Tanzania, including in the regions of Arusha, Kilimanjaro and Tanga to the northeast, Kagera and Kigoma regions to the northwest, and Katavi, Mbeya and Iringa regions in the Southern Highlands. Since 2002, Dr. Aiwerasia Ngowi, formerly of the Tanzania Pesticide Research Institute and now at Muhimbili University of Health and Allied Sciences in Tanzania, has widely studied the health threats of agrochemicals on small-scale coffee farmers in Tanzania and found one or more health problems related to pesticide exposure [1, 2]. A more recent study by Lekei and others in 2014 found high pesticide poisoning among farmers in northern Tanzania and recommended comprehensive interventions to reduce both exposure and health risks[3]. Local people in these areas have also complained about several health problems that are linked to frequent use of pesticides. Health experts, including medical doctors and agricultural extension officers have also reported pesticide poisoning cases in these areas. Field studies on pesticide poisoning including those mentioned above have shown that the most common short term effects include anxiety, dizziness, body itching and swelling as well as red eyes. Occasionally pesticide poisoning victims collapse in the field and lose consciousness. Long term impacts of pesticides among coffee farmers include weakness, memory loss and lack of concentration. Elsewhere, studies have shown that prolonged exposure to pesticides can also cause cancer and irreversible environmental harm. The list is long, but the fact is that there is a potential threat of pesticide poisoning to small-holder farmers that needs to be addressed.    

A typical scenario of potential agrochemical exposure and health threat among small-scale farmers in Tanzania  

On a normal day, small-scale coffee farmers in Tanzania wake up at six in the morning to tend their coffee farms usually together with family members such as women, children and the elderly who are most vulnerable to chemical exposures. They would do all kinds of activities such as pruning or picking ripe coffee fruits. Whenever it is necessary to apply pesticides to the crops, farmers mix the chemicals often without safety gloves or masks. The pesticides are then placed in a backpack and spraying starts immediately often without protective gear such as an overall or face mask. Most of the farmers and their assistants are not aware of the health hazard of the pesticide’s components and, since they are not properly protected, will inevitably touch, inhale or swallow some of the chemicals. Worse still, after removing the pesticides, these people continue using the empty containers for storing drinking water, table salt or cooking oil which puts them further at risk of pesticide poisoning. Since this is repeated, they will eventually develop short and long term health problems, in most cases without being aware.

Future Prospects and Recommendations

The potential threat of agrochemicals is not confined to Tanzanian farmers only but occurs in much of the developing world where small-scale farming of coffee and other crops is practiced. For instance, pesticide poisoning has long been recognized in China and India as studies show [4, 5]. Agrochemical threats are also not limited to coffee farming but extend to other crops with which large amounts of pesticides are used, especially cotton.  The persistence and importance of agrochemical threats in these areas are sometimes due to lack of appreciation of the problem and action about it by the appropriate government authorities. Nonetheless, some governments are trying their best to help the farmers in various ways. Their good intentions, however, fall short of what is required in the face of serious problems such as pesticide poisoning for various reasons including lack of financial and personnel resources for providing information and training on safe practices. In such circumstances, other stakeholders including development partners can support and supplement government efforts in tackling the problem.

Science also has a role to play here. The recently reported DNA sequencing of Robusta and Arabica coffee strains to produce genetically modified (GM) varieties of coffee resistant to diseases and pests is encouraging. If achieved, this will ultimately help to reduce the amount of pesticide spraying required for conventional coffee growing and hence reduce or stop the poisoning of farmers and their families. However, this may take some years before being realized. In the meantime, farmers should be trained in how to protect themselves against pesticide poisoning such as by wearing protective gear when handling the chemicals. First aid facilities for pesticide poisoning victims in coffee growing areas should be instituted. Alternative agrochemicals that are less hazardous or persistent in the environment should be produced. Pesticide manufacturers and traders should ensure that they label their products properly to warn of their hazards and advise on their use in local languages, and governments should legislate to enforce this.

The author is a lecturer and health researcher in the Department of Biological Sciences at Dar es Salaam University College of Education Tanzania. Contact him at:


  1. Ngowi, A.V.F., et al., Acute health effects of organophosphorus pesticides on Tanzanian small-scale coffee growers. J Expo Anal Environ Epidemiol, 2001. 11(4): p. 335-339.
  2. Ngowi, A.V., D.N. Maeda, and T.J. Partanen, Knowledge, attitudes and practices (KAP) among agricultural extension workers concerning the reduction of the adverse impact of pesticides in agricultural areas in Tanzania. Med Lav, 2002. 93(4): p. 338-46.
  3. Lekei, E.E., A.V. Ngowi, and L. London, Farmers’ knowledge, practices and injuries associated with pesticide exposure in rural farming villages in Tanzania. BMC Public Health, 2014. 14: p. 389.
  4. Zhang, X., et al., Work-related pesticide poisoning among farmers in two villages of Southern China: a cross-sectional survey. BMC Public Health, 2011. 11(1): p. 1-9.
  5. Mancini, F., et al., Acute pesticide poisoning among female and male cotton growers in India. Int J Occup Environ Health, 2005. 11(3): p. 221-32.