Polychlorinated biphenyl facts for kids
Polychlorinated biphenyls, usually called PCBs, are special man-made chemicals. They are made of carbon, hydrogen, and chlorine atoms. For many years, industries used PCBs in different products.
PCBs were once very common in things like transformers, capacitors, and cooling fluids. These chemicals were useful because they didn't burn easily and could handle heat well. However, we now know they are very harmful to the environment and to living things.
The Stockholm Convention on Persistent Organic Pollutants is an international agreement. It listed PCBs as some of the most dangerous chemical pollutants. Because of this, the use of PCBs has been banned almost everywhere in the world since 2001.
Even though they are banned, PCBs are still found everywhere. They are in the air, soil, and water all over the Earth. This is because they do not break down easily. They can stay in the environment for a very long time.
Contents
What Are PCBs?
PCBs are a group of chemicals that humans created. They are not found naturally. There are 209 different types of PCBs. Each type has a slightly different number of chlorine atoms.
How PCBs Were Used
For many years, PCBs were very popular in factories. They were good for electrical equipment. This is because they could resist fire and heat.
- Transformers and Capacitors: These are electrical parts. PCBs were used as insulating fluids inside them. This helped prevent fires.
- Cooling Fluids: In some machines, PCBs helped keep things cool.
- Other Products: They were also used in paints, plastics, and even some glues.
Why Are PCBs Dangerous?
PCBs are very harmful to people and animals. They are known as "persistent organic pollutants." This means they stay in the environment for a long time. They also build up in the bodies of living things.
How PCBs Harm Living Things
When PCBs get into the body, they don't leave easily. They build up over time, especially in fatty tissues. This can cause serious health problems.
- Not Immediately Toxic: A small amount of PCBs might not make you sick right away.
- Accumulation: But over time, more and more PCBs can collect in the body.
- Developmental Problems: PCBs can affect how babies develop before they are born. They can cause problems with growth and learning.
- Cancer Risk: Scientists believe that PCBs can increase the risk of getting cancer.
- Immune System: They can also weaken the body's ability to fight off sickness.
PCBs in Our World
Because PCBs were used so much, they are now found almost everywhere. They can travel long distances in the air and water.
- Food Chain: Small animals can take in PCBs from the environment. Then, bigger animals eat them. This way, PCBs move up the food chain. This means that animals at the top of the food chain can have high levels of PCBs in their bodies.
- Old Equipment: Many old transformers and other electrical devices still contain PCBs. These can leak into the environment if not handled carefully.
Images for kids
-
PCB warning label on a power transformer.
-
Old power transformers can contain PCBs. Even if they didn't originally, they might get contaminated if refilled with tools used for PCBs.
See also
In Spanish: Bifenilos policlorados para niños
