Dirty Dozen: Twelve Worst Persistent Organic Pollutants (POPs)

Persistent Organic Pollutants or POPs are the chemical substances that are toxic and do not disintegrate easily. POPs have huge environmental implications as these can move rapidly from one part of the world to another through repeated evaporation and deposition. These organic compounds used to be often used in agriculture and industries. Out of all these pollutants, twelve are particularly of concern.

Dirty Dozen is a name given to a set of twelve persistent organic pollutants that are most harmful to the environment and human life. Following is the list of dirty dozen POPs:

1. Aldrin,
2. Chlordane,
3. DDT,
4. Dieldrin,
5. Endrin,
6. Heptachlor,
7. Hexachlorobenzen,
8. Mirex,
9. Polychlorinated biphenyls,
10. Polychlorinated dibenzo-p-dioxins,
11. Polychlorinated dibenzofurans, and
12. Toxaphen

In 1995, the United Nations Environment Programme (UNEP) began investigating the role of these dirty dozen organic compounds in polluting the environment.

Properties of Persistent Organic Pollutants

• Organic chemical compounds
• Disintegrate extremely slowly
• Travel fast across the globe. Very difficult to determine the origin of POPs
• Lipophilic (meaning that POPs deposit in the fatty tissues of organisms)

International Conventions dealing with POPs and Pesticides

Many environment conventions have been organized to deliberate and deal with the menace of POPs. Following are noteworthy:

• Stockholm Convention
• The Basel Convention
• Convention on Long-Range Transboundary Air Pollutants (LRTAP)
• Globally Harmonized System (GHS) for Classification and Labelling of Chemicals
• International Convention on the Control of Harmful Anti-fouling Systems on Ships
• The Vienna Convention

Effects of Persistent Organic Pollutants

According to UNEP, the POPs can have the following effects on the human health:

• Death
• Cancers
• Allergies
• Hypersensitivity
• Developmental changes
• Damage to the central and peripheral nervous systems
• Disruption of the endocrine, reproductive, and immune systems

Present Status of the Dirty Dozen

Through resilient efforts, governments around the world have ensured that many of the dirty dozen POPs are no longer in use. However, in developing countries some of these are still in use. For example in India, DDT is banned for agricultural use but it is still used in fumigation against mosquitoes.