3rd April 2010
Obsolete pesticides are pesticides that are unfit for further use or for re-conditioning. Obsolescence may arise because a product has been de-registered locally or banned internationally. More commonly, however, a stock of pesticides becomes obsolete because of long-term storage during which the product and/or its packaging degrade. The total quantity of potentially obsolete pesticides held in developing countries and countries with economies in transition is thought to be huge, on the order of tens or hundreds of thousands of tonnes. The amount can only be estimated, however, because many stocks have not been inventoried or even located1. In 2002 FAO estimated that the toxic waste in Africa alone amounts to around 120,000 of the more than 500,000 tons worldwide. FAO previously estimated the amount in Africa at around 50,000 tons, with about 30 per cent of the waste believed to be persistent organic pollutants (POPs)2.
Most developing countries have outdated and deteriorated stocks of pesticides that can no longer be used as prescribed on the label. These stocks are often stored in poor conditions and pose a threat to human health and the environment. With the exception of a few newly industrialized countries, developing countries do not have adequate facilities to dispose of such stocks in a safe and environmentally sound manner. In many cases, therefore, the recommended disposal method would appear to be shipment of the pesticides to a country that has special hazardous waste incineration facilities. In view of the dangerous nature of these pesticides and the high costs of safe and environmentally sound disposal, the long-term solution to obsolete stocks lies in preventive measures: improved stock management and reduction of stocks3.
Various types of stockpiles of obsolete pesticides can be defined4:
Small quantities resulting from use - This group comprises those obsolete pesticides generated by producers, experimental stations or research institutes. Generally this means small quantities whose generation is disperse and fluctuating, but it is also expected that this waste stream is more or less the same in the different areas through time.
Obsolete pesticides generated in trade operations - These pesticides are found at identified pesticides trading companies but disperse throughout the countries. Their generation is directly related to the companies' activities in relation to product stockpiles management and generally because of prices, small quantities are involved.
Wastes from production or formulation of pesticides - These wastes are generated as a result of industrial activities. Their generation is a function of pesticides production, they are at a fixed facility and completely characterized.
Wastes from accidents - Accidents are the origin of these wastes. They might be generated during transport, by fire, spills or other accidents within the storing area. Their generation is eventual and disperse, quantities range from a few to several kilograms and the wastes are basically well characterized.
Deteriorated products - These are products that have deteriorated as a result of different circumstances: bad storage conditions that changed their physicochemical properties and therefore they can no longer be applied. The generation is eventual and disperse, the quantities are variable and basically the wastes’ characteristics are known.
Deposits - These are warehouses of different characteristics where quantities range from a few tens of kilograms to various tonnes of obsolete pesticides. Generally they were generated in the past but they still can be generated because of bad buying policies, inadequate deposits and poor stock management and also due to confiscation. Obsolete pesticides can be found in public or private facilities in any part, they might be part of an inventory or not and sometimes they might not even be identified. The abovementioned comprises old industries deposits, under no activity and that has become environmental liabilities. This is a heterogeneous group due to the types of products, quantities, containers and active ingredients conditions, storage conditions and the risk they represent.
Burials - This kind of disposal method was used in the past in various countries. This is usually named "contaminated site" but on account of the high soil contamination that can be present, burials might be considered as stockpiles. The buried quantities as well as the affected area and the risks involved are different from site to site. Additionally, the areas identification can also be difficult.
In most cases, the only option for dealing with unused and obsolete pesticides stocks is to destroy them. But destroying pesticide waste is neither cheap nor technically simple. Destruction processes vary depending on the type of contaminant. But in general high temperature incineration is the most widely used method. However, the incineration of hazardous waste is not without its problems. It can create toxic emissions, and although these emissions are relatively low compared to many other sources, they are nevertheless measurable. The incineration process also leaves ash that is hazardous and the filters that remove the toxic emissions become toxic.
In order to help countries deal with obsolete pesticides FAO has developed several guidelines giving information on the disposal of bulk quantities6, small quantities7, contaminated soil8 and on country guidelines9 as well as on good management practices to avoid a build up of obsolete stock3.
1. Report of the OECD-FAO-UNEP Workshop on Obsolete Pesticides, Alexandria, Virginia, 13-15 September 2000
2. Europaworld, 20th September 2002, Toxic Waste from Obsolete Pesticides in Africa Threatens Health, Says UN Agency
3. Plant Production and Protection Division, FAO, Rome, Italy, Prevention of Accumulation of Obsolete Pesticide Stocks
4. Basel Convention Coordinating Centre for Latin America and the Caribbean, Practical Guideline on Environmentally Sound Management of Obsolete Pesticides In the Latin America and Caribbean Countries, J. Martinez, Montevideo, Uruguay, November, 2004
5. UN Food and Agriculture Organisation, Prevention and Disposal of Obsolete Pesticides
6. UN Food and Agriculture Organisation, Disposal of bulk quantities of obsolete pesticides in developing countries
7. UN Food and Agriculture Organisation, Guidelines for the management of small quantities of unwanted and obsolete pesticides
8. UN Food and Agriculture Organisation, Assessing soil contamination: A reference manual
9. UN Food and Agriculture Organisation, Country guidelines
Last modified 3rd April 2010
Date added: 2010-01-26 22:43:12
Last Updated 2010-05-10 04:39:26
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