Pesticides become obsolete when they can no longer be used for their intended purpose. They are then banned, because of their prolonged impact on the environment and/or because they cannot be used due to age, deterioration or a change of specification of currently applied pesticides. Hence, the Obsolete Pesticides (OPs) problem does not concern the use of pesticides. Rather the problem is caused by pesticides that have not been used and thereby have become obsolete. The problem – in particular the associated risks stemming from their inadequate management and storage – relates to:
- Public health and environmental quality and
- Agricultural production and trade.
The problem dates back to the 1950s and 1960s when the use of pesticides in what were then Communist countries was increased in order to raise agricultural production.
Pesticides were distributed to farmers free of charge, leading not only to overuse and but also to unsound management of residuals and packaging materials. To date, it has been estimated that approximately 260,000 tonnes of OPs are at tens of thousands of locations in the countries of the former Soviet Union, the Southern Balkans and new EU member states – a region stretching from Poland to Kyrgyzstan.
What are POPs?
Persistent Organic Pollutants (POPs) are organic chemical substances, that is, they are carbon-based. They possess a particular combination of physical and chemical properties such that, once released into the environment, they:
- remain intact for exceptionally long periods of time (many years);
- become widely distributed throughout the environment as a result of natural processes involving soil, water and, most notably, air;
- accumulate in the fatty tissue of living organisms including humans, and are found at higher concentrations at higher levels in the food chain; and
- are toxic to both humans and wildlife.
As a result of releases to the environment over the past several decades due especially to human activities, POPs are now widely distributed over large regions (including those where POPs have never been used) and, in some cases, they are found around the globe. This extensive contamination of environmental media and living organisms includes many foodstuffs and has resulted in the sustained exposure of many species, including humans, for periods of time that span generations, resulting in both acute and chronic toxic effects.
In addition, POPs concentrate in living organisms through another process called bioaccumulation. Though not soluble in water, POPs are readily absorbed in fatty tissue, where concentrations can become magnified by up to 70,000 times the background levels. Fish, predatory birds, mammals, and humans are high up the food chain and so absorb the greatest concentrations. When they travel, the POPs travel with them. As a result of these two processes, POPs can be found in people and animals living in regions such as the Arctic, thousands of kilometers from any major POPs source.
Specific effects of POPs can include cancer, allergies and hypersensitivity, damage to the central and peripheral nervous systems, reproductive disorders, and disruption of the immune system. Some POPs are also considered to be endocrine disrupters, which, by altering the hormonal system, can damage the reproductive and immune systems of exposed individuals as well as their offspring; they can also have developmental and carcinogenic effects.