Do you have a very old refrigerator at home? Or perhaps an old freezer? Or maybe a few old cans of spray paint? These may contain chemicals such as chlorofluorocarbons also known as CFCs sold under the name Freon. If handled and used properly, CFCs are no threat to the environment. However, if they are mishandled and allowed into the air, the effects can be damaging. In this activity, you will learn about how chemicals dispersed into the environment can harm the planet.

Likely, you have heard of ozone — the ozone is a layer of molecules that sits on the outer edge of the atmosphere. Its one task is to absorb ultraviolet radiation from the sun. If this radiation gets through to Earth in great quantities, it can kill living things!

@gettyimages

 

 

At present, the ozone layer is becoming weaker and thinner due to the release of such things as CFCs. CFCs destroy ozone molecules. One result of the ozone layer becoming weaker is the increase in skin cancers, which are caused by ultraviolet radiation. The following film talks about the ozone layer.

Do you see how one chemical can cause great harm to the planet that we call home? Knowing the consequences of our actions is very important, not only for people and creatures today but for future generations. The video explains that if everybody on the planet stopped using CFCs today, it would still take 50 years for the ozone layer to replenish itself. What do you think about that fact?

Hundreds of fish are sometimes found dead on beaches. Large numbers of shellfish can suddenly start to die off. People become seriously ill after eating certain shellfish. Deadly toxins are often found in these sick or dead organisms. But where have these toxins come from?

 

@creativecommons

 

@creativecommons

Algae are plant-like organisms. They are the base of most food webs in the ocean and freshwater. Very tiny phytoplankton cells (a type of microscopic algae) can produce potent toxins. Phytoplankton is eaten by tiny microscopic animals. The toxins don’t seem to harm these small creatures. They live in swarms of billions of individual little animals and are eaten (along with phytoplankton) by many animals from tiny shrimp to the largest of mammals.

These toxins can accumulate quickly through the food web as each consumer takes in more and more of the toxin. Organisms such as mussels and fish have been found to retain toxins from phytoplankton in their bodies. These organisms are often not affected by the toxins but pass the toxins on further along the food web. The larger animals get the bigger doses of toxins. In many cases, toxins can be transported through the food web to humans, often through contaminated shellfish.

These toxins can affect people in different ways, from mild illness to death. There are several types of toxins produced by the harmful algae. Commonly, the toxins affect the functioning of nerve and muscle cells.