What is in your doodh patti?
Monday, September 17, 2012
Persistent Organic Pollutants (POPs) are toxic substances released into the environment through a variety of human activities. They are very stable and long-lived chemicals that build up in the food chain and slowly poison animals and humans. POPs are lipophilic and tend to accumulate and also magnify in the fatty tissues of living beings. When they enter the body they don’t leave it and are persistent. They are also semi-volatile, which means that they can stay on the ground for a number of years and then be transported hundreds of miles away and be deposited in another place until they eventually end up in animals and humans. They are also subject to global distillation i.e. migration from warmer to colder regions called the ‘grasshopper effect’. For example, a pesticide used in Asia can easily move to Europe.
The pollution of the human body by POPs has occurred together with the appearance of several alarming trends in human health over the past few decades. Almost everything we eat, drink or inhale is broken down by our bodies and then expelled through the process of waste elimination. But POPs are not. As we age their concentration become higher, and their potential effects on our health become more serious. People consuming excess fat are subjected to greater risk. In the United States, a recent study conducted by National Academy of Sciences estimated 20,000 cases of cancer a year, due to pesticide abuse alone. Furthermore, there is increasing evidence of the oestrogen effect of POPs. Many scientists believe that toxic agents in the environment have reduced the average sperm count in men by 42% in the past 50 years, and rising percentage of sperms are deformed and non-functional. Testicular cancer is on the rise, as are birth defects such as undescended testicles and menstrual disorders such as endometriosis. Toxic exposures during foetal development, infant life and childhood can have life long effects including increased susceptibility towards cancer and damage to the immune and reproductive systems. PCBs and dioxins are even suspected to contribute to learning disabilities.
POPs are found in common places. Electrical transformers contain PCBs. Dioxins, furans and other POPs are created during the manufacture of paper and vinyl plastic, which is used in making children’s toys, clothing, polybags and tubing, flooring, pipes and siding. When vinyl is incinerated or burnt in a backyard trash fire, dioxin is formed again. Dioxins are also formed during the manufacture of magnesium and other metals. POPs enter our bodies mainly through food. POPs accumulate in fat and their concentration increases at each step of the food chain. For example, PCBs have been found to accumulate in the liver of sheep. Dieldrin accumulates in the wool of sheep that feed on contaminated land. Children are more vulnerable than adults to many kinds of pollution, POPs being the major one. Many POPs have been detected at significant levels in the breast milk of some women from many countries worldwide. By threatening the health and survival of our children, POPs threaten our future generations too.
PCBs are typical industrial contaminants and can be found everywhere in the environment. In the nutrition chain there is a significant cumulation and in breast milk and in human fat. PCBs are very persistent, hydrophobic, and generally do not migrate. Dioxins and furans have never been manufactured deliberately, except in small amounts for research purposes. They are unintentionally created in two major ways - 1) by the process used to manufacture some products like pesticides, preservatives, disinfectants and paper products. 2) when materials are burnt at low temperatures, for example, certain chemical products, leaded gasoline, plastic, paper and wood. Dioxins can be inadvertently formed during the manufacture of a group of chemicals called chlorophenols, used to preserve wood, hides, textiles, paints, glues, etc. Open burning of household waste in barrels is potentially one of the largest sources of airborne dioxin and furan emissions. Dioxins/furans are widespread in the environment and persist over long periods of time. Although they are most often associated with industrial activities, some natural occurrences such as forest fires are also believed to make a small contribution to their presence in the environment. These compounds have been measured in air, soil, sediments, meat, milk, fish, vegetables and human biological samples.
Green Peace investigations conducted in 1998 in seven Asian countries, including Bangladesh, India, Nepal and Pakistan revealed:
- Stocks of 5,000 metric tons or more obsolete pesticides, including POP chemicals are stored in extremely hazardous conditions in some of these countries.
- India is among the three remaining known manufacturers of DDT in the world, the other two being Mexico and China.
- India exports nearly 800,000 kg of POP pesticides including aldrin, DDT, BHC chlordane to a long list of countries where their usage is banned. Some of the pesticides such as aldrin are not permitted to be manufactured even in India.
- In Pakistan, India, Nepal and Bangladesh, locally banned or severely restricted pesticides are freely available. Green Peace found DDT, BHC, dieldrin and heptachlor openly sold in the vegetable markets of Karachi. Hardware stores of New Delhi stock the deadly pesticide aldrin whose registration was withdrawn more than three years ago.
These findings appeared in a slightly dated article, ‘Living in a Chemical Environment -Persistent Organic Pollutants’ by rashmi sanghi in the journal ‘Resonance’ but are still relevant today. [Daily Times Monitor]
posted by S A J Shirazi @ 3:57 PM,
- At September 18, 2012 at 1:24 PM, Kausar Bilal said...
Very well written and a very informative article...
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