FORMER Department of Health (DOH) Secretary Francisco Duque lied to President Gloria Macapagal Arroyo when he issued a memorandum urging her to issue an executive order that will ban aerial spraying supposedly based on the World Health Organization’s letter to the DOH recommending the banning of aerial spraying based on their experts’ peer review of a DOH-commissioned study.
The said letter dated November 3, 2009, however, clearly states that “WHO does not have a formal position on aerial pesticide spraying for agricultural purposes.”
Before the letter was sent, a teleconference was held on October l9.2009 at the WHO’s regional office in Manila among WHO representatives led by Dr. Soe Nyunt-U, two of the three experts—Dr. David Coggon of the United Kingdom and Dr. Brian Priestly of Australia—who peer reviewed the study and l8 Philippine Government representatives from the DOH, Fertilizer and Pesticides Authority, Department of Agriculture, Department of Environment and Natural Resources, Department of Labor and Employment, University of the Philippines National Poison Management and Control Center and Philippine Society of Clinical and Occupational Toxicology.
Discussed during the teleconference were the findings of the panel of experts organized by the WHO upon DOH’s request who peer reviewed the study on Health and Environmental Assessment of Sitio Camocaan, Hagonoy, Davao del Sur commissioned by the DOH.
Dr. Allan R. Dionisio, author of the study, explained during the teleconference that his study is a health and environment assessment and it is not focused on aerial spraying. According to Dionisio, it is a technical report for the DOH officials and not intended to be published in a journal, thus the format was different.
The WHO experts found several major limitations in the study so they could not recommend a ban on aerial spraying based on the study. Instead, they suggested that the DOH do its homework by reviewing available literature and data from other countries. Dionisio’s study, in other words, was not able to stand the scientific scrutiny of the peer review.
Dionisio’s clarification on the format is immaterial; it is not the form but the substance that made his study unacceptable. The results of his study were found to be so weak that it would never see print in any respectable scientific journal.
The international experts from the WHO found the study to be weak in the following points:
a) Small sample size leading to statistical uncertainties
b) Other possible sources of exposure other than aerial spraying on bananas such as spraying of other crops like mango
c) Potential biases due to incomplete responses on health outcomes and measurement errors
d) Inclusion of farm workers as subjects
e) Lack of critical information on the assessment of exposures
f) History on the nature of pesticide application in the nearby banana plantation
g) Over-reporting of symptoms and unvalidated interview information
h) Domestic use and storage of pesticides
i) Lumping all respondents (children and adults) and no breakdown of subjects by age and gender
The evaluation of the WHO experts implied that the Dionisio study does not have any value in the formulation of a national policy to ban aerial spraying of fungicides in banana plantations. The DOH-commissioned study did not have the scientific vigor to address whatever perceived health concerns that were earlier expressed by Dr. Romeo Quijano in his numerous and well publicized articles that convinced several sectors of civil society to advocate the ban. Quijano’s articles led the DOH to fund the study.
The third WHO expert, Dr. Aqiel Dalvie of South Africa, who was unable to participate in the teleconference, supports the banning of aerial spraying but recommended surveillance, environmental monitoring and further epidemiological study on health effects of pesticide usage.
The WHO experts recommended that national legislation should govern the use of pesticides and introduce buffer zones where pesticides are applied to protect neighboring communities.
Other countries use aerial spraying and regulate its use to protect human health and environment. A 30-meter buffer zone is in effect in the Philippines but the banana plantations are actually applying a 50-meter buffer zone. The buffer zone in Tasmania, Australia is 50 meters; 25 to 30 meters in New South Wales and l5 meters in the US for chlorothalonil (one of the substances used in banana plantations).
The size of the buffer zones depends on the product being sprayed. He said that the Food and Agriculture Organization suggests a 5-kilometer buffer for organochlorine insecticides (DDT—another very interesting topic). “Some are based on specific sites like the l50-meter buffer from any dwelling, school or factory premises. Only fungicides are sprayed in banana plantations and these are definitely less toxic than insecticides.
The buffer zone is important in aerial spraying to protect the communities and other areas from the fungicide drift that is claimed by the NGOs to reach as far as 3.2 kilometers. An international drift expert, however, clarified that the 3.2 kilometer drift being cited by the NGOs must be for the eradication of locusts, mosquitoes and other insects since the airplane is flying higher over a community to cover a wider area. It could also be the result of spraying operations done at higher altitudes and at worst conditions of wind speed, temperature, nozzle size, among others. Definitely, spraying in bananas is not done under these conditions.
A recent visitor to the Philippines who was invited by the FPA to visit a banana farm in Davao del Sur that was the subject of the DOH study is British expert Dr. Andrew Hewitt of the University of Queensland and one of the few would experts on bio-aeronautics.He has conducted hundreds of studies on aerial spray for almost 20 years in Costa Rica, the United States, New Zealand, Australia and the United Kingdom.
He said that the airplane used in banana plantations flies just over a few feet above the canopy of the bananas.Among his observations from his visit in a banana farm in Camocaan, Hagonoy, Davao del Sur is that aerial spraying does not product a drift of the chemicals used, thus belying crtitics’ claim that the drift reaches as far as 3.2 kilometers. The aircraft in banana plantations sprays the fungicide down.
He said that based on what he saw aerial spraying in the Davao region can be among the best practices in the world because it is done professionally and properly. He also said that the spraying protocols and equipment used by the airplanes such as computers and nozzles were all studied by the team which he headed and now used as a model—AgDrift—to assess risk in aerial spraying of pesticides by the US Environmental Protection Agency (US EPA). He cited the need to protect the local banana industry while at the same time protect the environment and the health of the people.
Dr. Hewitt also observed that the banana farm he visited in Camocaan adhered to a prescribed buffer zone and there is no extensive drift from aerial spraying to the community. “The drift in the Camocaan area could be a couple of meters,” he said.”Rather than ban aerial spraying, we can regulate it.”
Dr. Norlito Gicana, executive director of FPA, said Dr. Hewitt’s recommendations can help strengthen the policies and conditions of regulating aerial spraying. As an independent drift expert, Gicana said Dr. Hewitt will be most helpful in doing a drift study in Mindanao.”
Gicana who was also present during the WHO-organized teleconference said that the FPA supports the conduct of another study to rectify the limitations of the current study. He stressed that immediate banning of aerial spraying will not just displace a lot of people but will also affect the economy because there will be hundreds of hectares that cannot be sprayed as these do not have roads for ground spraying trucks. It will take weeks for workers to spray these manually and will expose them to the fungicide spray solution day in and day out. The health risk to workers of such a continuous exposure has not been studied so it cannot be an option. Thus, this will mean practically giving the fungus that causes sigatoka the opportunity to ruin the banana plantations in just a matter of weeks.
Anthony B. Sasin
(The author is spokesman for the Pilipino Banana Growers and Exporters’ Association.)