:: What Are Pops ::

Persistent Organic Pollutants.

Persistent Organic Pollutants - POPs were widely used
during the boom in industrial production after
World War II, when thousands of synthetic chemicals
were introduced into commercial use. Many of these
chemicals proved beneficial in pest and disease control,
crop production, and industry. These same chemicals,
however, have had unforeseen effects on human health
and the environment.

Many people are familiar with some of the most
well-known POPs, such as PCBs, DDT, and dioxins.
POPs include a range of substances that include:

Intentionally produced chemicals currently or once used in
agriculture, disease control, manufacturing, or industrial processes. Examples include PCBs, which have been useful in a variety of industrial applications (e.g., in electrical transformers and large capacitors, as hydraulic and heat exchange fluids, and as additives to paints and lubricants) and DDT, which is still used to control
mosquitoes that carry malaria in some parts of the world.

Unintentionally produced chemicals, such as dioxins, that result from some industrial processes and from combustion (for example, municipal and medical waste incineration and backyard burning of trash).

DDT is likely the most famous and controversial pesticide ever made. An estimated 4 billion pounds of this inexpensive and historically effective chemical have been produced and applied worldwide since 1940. In the United States, DDT was used extensively on agricultural crops, particularly cotton, from 1945 to 1972. DDT was also used to protect soldiers from insect-borne diseases such as malaria and typhus during World War II, and it remains a valuable public health tool in parts of the tropics. The heavy use of this highly persistent chemical, however, led to widespread environmental contamination and the accumulation of DDT in humans and wildlife -
a phenomenon brought to public attention by Rachel Carson in her 1962 book, Silent Spring. A wealth of
scientific laboratory and field data have now confirmed research from the 1960s that suggested, among other effects, that high levels of DDE (a metabolite of DDT) in certain birds of prey caused their eggshells to thin so dramatically they could not produce live offspring.

One bird species especially sensitive to DDE was the bald eagle. Public concern about the eagles’ decline and
the possibility of other long-term harmful effects of DDT exposure to both humans and wildlife prompted the Environmental Protection Agency (EPA) to cancel the registration of DDT in 1972. The bald eagle has since experienced one of the most dramatic species recoveries in our history.

How Do POPs Affect People and Wildlife?

Studies have linked POPs exposures to declines, diseases, or abnormalities in a number of wildlife species, including certain kinds of fish, birds, and mammals. Wildlife also can act as sentinels for human health: abnormalities or declines detected in wildlife populations can sound an early warning bell for people. Behavioral abnormalities and birth defects in fish, birds, and mammals in and around the Great Lakes, for example, led scientists to investigate POPs exposures in human populations.

In people, reproductive, developmental, behavioral, neurologic, endocrine, and immunologic adverse health effects have been linked to POPs. People are mainly exposed to POPs through contaminated foods. Less
common exposure routes include drinking contaminated water and direct contact with the chemicals. In people and other mammals alike, POPs can be transferred through the placenta and breast milk to developing offspring. It should be noted, however, that despite this potential exposure, the known benefits of breast-feeding far outweigh the suspected risks.

A number of populations are at particular risk of POPs exposure, including people whose diets include large amounts of fish, shellfish, or wild foods that are high in fat and locally obtained. For example, indigenous
peoples may be particularly at risk because they observe cultural and spiritual traditions related to their diet.
To them, fishing and hunting are not sport or recreation, but are part of a traditional, subsistence way of life, in which no useful part of the catch is wasted. In remote areas of Alaska and elsewhere, locally obtained subsistence food may be the only readily available option for nutrition.

In addition, sensitive populations, such as children, the elderly, and those with suppressed immune systems,
are typically more susceptible to many kinds of pollutants, including POPs. Because POPs have been linked to reproductive impairments, men and women of child-bearing age may also be at risk.

Reference: The Environmental Protection Agency USA.

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