Product stewardship is the responsible and ethical management of crop protection products (CPP) from discovery through to ultimate use and beyond. Stewardship is actively promoted by the FAO through the FAO Code of Conduct and encourages all stakeholders to play their part in the safe distribution and use of Crop Protection Products (CPPs).
Those involved in ensuring that all approaches to crop protection are safe, effective and sustainable should visit the Pesticidewise website.
The industry association, CropLife, also takes an active approach with stewardship programs around the world. Its publications offer support and advice on key topics such as personal protection when using CPPs in hot climates and the Safe and Effective Disposal of Crop Protection Product Containers.
Basic training programs can improve safe pesticide handling practices in developing countries. Examples of industry-led education and training efforts include:
Training programs are conducted globally under the Syngenta Good Growth Plan (GPP).
Alliances of industry, academic institutions, government agencies, NGOs and others continue to play a part in promoting the effective and safe use of paraquat and all CPPs.
Stewardship efforts related to paraquat include extensive studies and incident case collection from poison control centres to assess the safety of paraquat in use. Results of these programs have confirmed that paraquat is safe when used according to the label instructions.
Paraquat is non-volatile and the spray droplets emitted are too large to enter the lung and is poorly absorbed through the human skin.
Studies on the effects from day-to-day use
Effects from contact with paraquat during spray operations can occur due to an irritant action of paraquat as a result of poor working practice and hygiene (Howard et al, 1981).
However, surveys interviewing smallholder farmers in Malaysia (Whitaker, 1989a), Central America (Whitaker, 1989b) and Thailand (Whitaker et al., 1993) showed that, in general, farmers were aware of the potentially adverse effects of exposure and the need for caution when handling pesticides, including paraquat. Spray practices and standards of personal hygiene were generally adequate, although better adherence to PPE recommendations for all crop protection products, in particular, the wider use of hand and eye protection when handling the concentrate, was needed.
Effects from long-term use have also been studied
There is a substantial body of evidence in the medical literature, which has accumulated over decades, regarding the question of long-term effects from occupational exposure to paraquat. Examples of these studies include:
"Malaysia oil palm plantation workers" – British Journal of Industrial Medicine, 1980. This study concluded that: “Long term Paraquat spraying at the concentrations used produced no quantifiable harmful effects as measured by the indices selected for this study.”
"Sri Lanka tea plantation workers" – British Journal of Industrial Medicine, 1993. This study concluded that: “Long term spraying of Paraquat produced no adverse health effects in particular no damage attributed to the occupational use of the herbicide.”
All studies agree that under the normal, typical use conditions in developing countries there is no evidence from medical examinations, chest radiography, spirometry or gas transfer measurements, that paraquat causes any long-term health effects.
Two investigations (Castro- Gutierrez et al, 1997 and Dalvie et al, 1999) claim to have found adverse health effects either in symptom reporting or in exercise-induced oxygen desaturation. However, there are serious methodological concerns over both of these findings, and they contrast with other objective measurements in the same studies showing no adverse health effects.
In order to fully investigate these effects, workers in coffee, banana, and oil palm plantations in Costa Rica were studied by Professor M. Schenker, from the University of California in Davis, CA, USA, during 2001-2002. This is the largest-ever health monitoring study on paraquat-exposed workers.
No clinically significant differences were detected in the respiratory function of exposed or non-exposed workers in all major outcome measures. This indicates that paraquat is not associated with the development of restrictive or obstructive lung disease and supports the continued safe use of paraquat under existing label conditions. (Schenker MB et al 2004).
The above work suggests that in day-to-day use paraquat can be used safely. In long-term use workers’ health is not adversely affected by paraquat.
Rules for safe use
As with all pesticides, normal user precautions need to be taken when using and handling paraquat. Put simply, these are:
- Exercise caution at all times
- Read and understand the product label
- Ensure good personal hygiene
- Ensure care and maintenance of application equipment
- Use personal protective clothing and equipment (PPE) where required
For more details on training in the Five Golden Rules for safe use of CPPs click here.
Labels and Pictograms
Labels are an important source of information for farmers on how to use and apply products in a way that is effective against the target pest, yet doesn't pose unnecessary risks for people or the environment. When used according to the instructions provided by leading manufacturers on every package, paraquat poses no unacceptable risk to farmers, society or the environment.
However, in some developing countries, low levels of literacy may mean some farmers can't read the label. Implementation of farmer training programs and widespread adoption of pictograms as a tool to more easily understand safety instructions are included on product labels to support the label text
Accidental and deliberate ingestion
Strong stewardship actions to prevent accidental and deliberate abuse of paraquat have led to the development of:
- Clear directions to encourage growers to securely lock away all crop protection products
- A Paraquat Treatment booklet and urine testing kits
- Training in treating cases of deliberate or accidental ingestion
- Communicating adsorbents such as activated charcoal as an effective means of treating patients after deliberate or accidental ingestion. Free diagnostic kits have been provided as an aid for many years.
- Contribution to suicide prevention initiatives with global and local suicide prevention agencies encouraging safe and secure storage.
For a more complete understanding of treatment options and how paraquat affects the human body, please click here.
Commentators have noted the beneficial effect of these stewardship activities in countries such as Malaysia and Costa Rica (Sabapathy, 1995; Wesseling et al, 1997).