Video Transcript
What process can be used to reduce
the amount of pollution in water? (A) Water analysis. (B) Storage in plastic bottles. (C) Water purification. (D) Storage in tanks on the roofs
of buildings. (E) The addition of arsenic to the
water.
Water pollution can be divided into
two main categories. There are artificial pollutants and
natural pollutants. Natural pollutants are formed by
natural disasters or other phenomena in nature. For example, volcanoes, lightning,
and the decay of plant and animal life can all release natural pollutants into
water. Artificial pollutants are formed by
human activities. Artificial water pollutants may be
biological, chemical, thermal, or radiant. Manufacturing in factories or the
refining of oil are examples of human activities that release many chemical
pollutants into our water sources. This leads to an increase in the
concentration of harmful substances in our water.
Now, let’s look at the answer
choices to see which one describes a process that can be used to reduce, or
decrease, the amount of pollution in water.
Let’s start with answer choice
(A). If we wanted to find out what type
of pollutants are present in water, we could analyze the water. Scientists may analyze water to
find out if it is safe to drink. Analyzing water does not reduce
pollution, but it could tell us if water is polluted and help us to make a plan to
reduce the pollution. So, answer choice (A) is not
correct.
Now, let’s look at answer choices
(B) and (D). These two answer options describe
ways to store water. Drinking water is often stored in
plastic bottles. But many plastic bottles contain
the chemical pollutant BPA, which is harmful to human health. BPA stands for bisphenol A. BPA can leave the plastic material
of the bottle and enter the water. It can also react with chlorine in
the water to form even more harmful substances. Drinking water is also often stored
in large storage tanks on top of buildings.
To make sure that no harmful
microorganisms, such as bacteria, are growing in the water, the tanks must be
disinfected regularly. Bacteria can be harmful to human
health and are considered biological pollutants. Storing water in a container can
prevent the water from being contaminated with some pollutants. But, as we’ve learned, storage of
water in plastic bottles or storage tanks could actually lead to an increase in
pollutants in the water. So, we can eliminate answer choices
(B) and (D).
Now let’s look at answer choice
(E). The element arsenic is found in the
earth, but it is also a part of some artificial pollutants, such as pesticides. Arsenic is toxic to humans. If arsenic is added to water, this
increases the amount of dangerous chemical pollution in the water. So, answer choice (E) is also
incorrect.
This leaves only answer choice (C),
which must be the correct answer. Water purification is a process
that can reduce or remove pollutants from water so that it is safe to use or
drink. In conclusion, the process that can
be used to reduce the amount of pollution in water is answer choice (C), water
purification.
