Questões de Concurso Comentadas para professor - inglês

  Water, Water Everywhere

Approximately 70 percent of our planet is covered in water. In total, that’s approximately 1,260 million trillion liters, which sounds like an enormous amount, but less than one percent of it can easily be used as drinking water. A major amount, 97 percent, is salt water, and two percent is glacier ice. Scientists and politicians are becoming increasingly worried about the amount of water, and predict that there will be wars in the future to control our water supplies.

      The world’s population is growing rapidly, and the need for water in industry and agriculture is enormous. Climate change also adds to the problem: droughts restrict access to water even further, and flooding can pollute supplies of drinking water. Furthermore, these threats to our environment are probably only going to get worse. Already 1.2 billion people live in areas with limited access to water, and the UN predicts that, by 2025, this figure will rise to 1.8 billion, or two thirds of the world’s population.

      But the problem isn’t only how much water we need, it’s also how we clean and store it. In the US, for example, water facilities are old and inefficient, and it’s hugely expensive to improve them. In China, the government knows it will need to spend $850 billion to improve its water infrastructure. Currently, India can only clean about 30 percent of its wastewater, meaning that people risk disease when they drink from polluted sources. Some countries filter sea water to make their drinking water. But this process is also very expensive, so it isn’t viable in many countries.

      We can’t give up on this problem, however, because without water we can’t survive. Thankfully, there are already some excellent water purification products operating on a small scale, which are already helping people whose access to water is limited.

      The “Slingshot” is a new water purifier, about the size of a small refrigerator, and is the creation of American inventor Dean Kamen. The purifier works by heating the water, which kills anything harmful. It can purify even the dirtiest water, requires minimal electricity, and can clean up to 1,000 liters a day. The “Slingshot” is already helping communities in several countries, including South Africa and Mexico. It will soon provide a cheap and safe supply of water in many other places where poverty prevents access to clean water.

      Dean Kamen believes that every human should have the right to clean water every day. Hopefully, with more devices like the “Slingshot”, there will soon be more water to go around.