Humanity deposits many toxic substances under the ground. Most of those are radioactive materials, pesticides, heavy metals and other kind of poisonous wastes. Even if they are first deposited in lakes, rivers or the sea, waters transfer most of them in the soil, when the latter absorbs water. It happens the other way round as well, as chemicals within soil are transferred with the rain into marine ecosystems.

Soil contamination is as a serious problem as any other form of pollution, but it was discovered later than them. Although it is connected with water pollution, the procedure is slow, and at first not even plants show any difference to point out pollution. If not stopped in time, it leads to desertification and destruction of the whole ecosystem. Many species lose their habitat, face extinction, or accumulate toxic substances in their body and become infected and poisonous for their predators.

Desertification never describes the presence of a natural desert. It is the process of making an area look like a desert, having its characteristics while it should not. It is caused by acid rain, deforestation and the setting of fires. Also, because of overgrazing when plants start to grow again after a fire. Most of the times there is a combination of some or of all those factors, which are all connected with human activities.

During desertification, many animal species die or lose their natural habitat. Plants disappear and face extinction. Valuable sources are lost, as fewer plants produce less oxygen. Thus, it is connected with global warming and climate change. Moreover, desertification often results in floods, as there are no trees to keep the soil steady with their roots. Floods harm both natural ecosystems and human properties, sometimes including death tolls.

Consequently, desertification is a very serious problem and should be solved. Laws ought to be passed in order to decrease the amount of trees cut down and of wooden products one can buy. Carbon dioxide emissions, by which acid rain is caused, must be reduced to prevent soil erosion. Authorities have to protect forests, by organising fire brigades and immediate reforestations. Animals that graze should be kept away from burnt areas where plants have just started to grow again.

When household and industrial wastes are disposed into the water, they increase the quantity of germs in it. Germs threaten the health of the organisms living in the water, drinking it or feeding on organisms that live in it. Moreover, huge quantities of nitric and phosphoric salts enter the ecosystem. Phytoplankton, the tiniest sea organisms that can photosynthesize and depend highly on those salts, start to grow in population at top speed, consuming oxygen. As a result, zooplankton which feeds on phytoplankton starts to increase in numbers, again consuming oxygen and producing carbon dioxide.

After some time, during which those small organisms continue to consume oxygen and produce larger amounts of carbon dioxide, there is not enough oxygen to sustain bigger organisms, like fish, who actually die of suffocation.

Lakes are the most usual ecosystems harmed by eutrophication. Oxygen cannot be easily diminished in the sea, and the movement of the water in rivers transfer the salts else where. The most common sign of eutrophication is the waters having a deep green colour. And as human wastes increase, ecosystems become more fragile and their living organisms more vulnerable to suffocation.

Consequently, one of our first priorities, as far as those ecosystems is concerned, is to find alternative ways of removing our industrial and household waste, so that it doesn’t end up in the water. The top priority, needless to say, is to reduce those wastes.