USE OF Dichloro-Diphenyl-Trichloroethane(DDT) in Ghana for Malaria Control
The World Health Organisation (WHO) in September 2006 announced that nearly 30 years after phasing out the widespread use of indoor spraying with DDT and other insecticides to control malaria, this intervention will
once again play a major role in its efforts to fight the disease.
Although DDT has been banned from agricultural use in most countries it continues to be used in limited quantities for public health purposes. Countries continue to use DDT primarily because they cannot afford reliable alternatives or do not have the capacity to develop them.
DDT which was widely used in Ghana for agricultural and public health purposes was officially banned in 1985 due to its damaging effects on human health and the environment. The Environmental Protection Agency is the regulatory body in Ghana with the mandate to register pesticides for use in the country.
Recent pronouncements by the WHO recommending the re-introduction of DDT for disease vector control have necessitated the preparation of this paper, which provides an overview on the status of DDT in relation to some international conventions and the Pesticides Control and Management Act, 1996 (Act 528) to equip government with the relevant information on the chemical.
2.0 Status of DDT in relation to the Stockholm Convention
The Stockholm Convention on POPs entered into force on 17th May 2004 with an objective to protect human health and the environment from Persistent Organic Pollutants (POPs) which include DDT. Ghana ratified the Convention and is thus obliged to abide by its provisions. The Convention contains details of conditions under which DDT may be produced and used in any country (Annex B, Part II of the Stockholm Convention). These are as follows:
1. DDT may be produced and used only for disease vector control and according to the recommendations and guidelines of the World Health Organisation. DDT may be used when safe, effective and affordable alternatives are not locally available in a country.
2. The WHO recommends only indoor residual spaying of DDT for disease vector control.
3. A country that decides to produce and/or use DDT for disease vector control is required to notify the Convention Secretariat and the WHO. All countries that so notify the Secretariat will be entered in a public register.
4. Every three years, each country that uses DDT will be required to provide to the Convention Secretariat and the WHO information on the amount of DDT used, the conditions under which it is being used, and how such use relates to the country’s disease management strategy. The reporting will be carried out in a format to be determined by the Conference of Parties in consultation with the WHO.
5. Countries using DDT will be supported and encouraged to strengthen their vector control programmes. The intention is to reduce and ultimately eliminate the use of DDT over time, by making such use unnecessary. In this connection, each country will be assisted to develop a national action plan that will include:
a. The development of regulatory and other mechanisms to ensure that DDT is used only for disease vector control
b. The implementation of alternative products, methods, and strategies, including vector resistance management strategies to ensure that the DDT alternatives remain effective. In developing such DDT alternatives, adequate consideration will be given to ensuring that viable alternatives present less risk to human health and the environment, and also that the alternatives are suitable for disease control within the particular context of each country.
3.0 Status of DDT in relation to the Rotterdam Convention
The Rotterdam Convention on the Prior Informed Consent (PIC) procedure for certain hazardous chemicals and pesticides in international trade came into force in February 2004. Ghana ratified the convention and DDT is listed among the chemicals subject to the PIC procedure. The implication is that Ghana needs to seek or consult its trade partners if DDT should be imported into the country.
4.0 Status of DDT in relation to the Pesticides Control and Management Act, 1996 (Act 528).
The Pesticides Control and Management Act, 1996 (Act 528) stipulates that ‘No person shall import, export, manufacture, distribute, advertise sell or use any pesticide in Ghana unless the pesticide has been registered by the Environmental Protection Agency in accordance with this Act’. DDT has been banned and is currently prohibited for use in the country. Under Act 528, a pesticide is banned when its use in accordance with widespread commonly recognized practice even in the presence of additional regulatory restrictions will cause unreasonable adverse effect on people, animals, crops or on the environment.
Section 2 of Act 528 however stipulates that the Agency may authorize the importation of an unregistered pesticide in the event of national emergency or if the Minister responsible for the Environment by legislative instrument so prescribes.
4.1 Available alternatives to DDT
The EPA has approved four pesticide products for residual spraying purposes. These are Bistar 10 WP (Bifenthrin), Icon 10 CS (Lambda cyhalothrin), Delete 2.5 EC (Deltamethrin) and Vectoguard 40 WP (Pirimiphos methyl). These products have been tried and tested by the WHO and recommended for residual spraying against mosquitoes.
5.0 Possible problems associated with the use of DDT in Ghana
Problems associated with the use of DDT in Ghana include the following:
5.1 Environmental problems
DDT is a Persistent Organic Pollutant (POP) and the effects of the pesticide on the environment will increase if appropriate measures are not taken to control its use/abuse if introduced. Cleaning of sites contaminated by DDT and disposal of obsolete stocks is expensive and difficult and should be avoided where possible.
5.2 Possible misuse on agriculture
The use of DDT in agriculture was banned since 1985. DDT is however very cheap compared to other pesticides and also known to be very effective against a broad range of insect pests. These properties of the chemical will make it very attractive to farmers to misapply on their crops leading to high levels of environmental and human exposure when the pesticide is introduced. DDT, which was previously used extensively on cocoa in Ghana, is currently not permitted by the European Union, Japan and other countries on cocoa. If allowed in the country, misuse on cocoa (a major foreign exchange earner) could lead to rejection of cocoa exports by importing countries if residues of the pesticide is detected.
Based on the above, the EPA recommends that the Government of Ghana should resist any external pressures to re-introduce DDT into the country since equally effective alternatives have been approved for use in the country. The use of these alternative pesticides should be intensified to control malaria in the country. The Stockholm Convention only recommends the use of DDT if safe, effective and affordable alternatives are not locally available in a country.