Water Pollution
تلوث المياه

In addition to clean air, all animals and plants need a clean water
supply in order to survive. You may think that we have lots of water but
only a small amount of it is freshwater that we can use and we are
.polluting our water in the same way we are polluting our air

When harmful substances such as oil and chemical wastes enter the
waterways either through accidents or through being intentionally dumped,
they are soon carried away by tides or the flow of the river and are
extremely difficult to remove. As a river makes it's way to the ocean, a
number of different chemicals can enter its waters. Harmful chemicals can
enter our rivers and lakes from any number of sources. For example they
can seep out of dumpsites or pesticides and fertilizers may drain from
farmlands or they may find their way into sewage that is pumped from
local towns and cities

One of the most damaging forms of water pollution is from oil. Oil spills
from ships and oil tankers at sea cause devastating water pollution and
harm wildlife. These events receive lots of attention on television and
from environmental groups, however these spills only represent a small
.percentage of the total amount of oil that contaminates our water
,Tankers dump oil into oceans as part of their routine cleaning
refineries pump oily wastewater into surface water and oil from city
.streets are washed into storm drains that eventually enter our waterways

When people rinse materials down the drain, flush their toilets or do a
load of wash, the wastewater usually goes to sewage treatment plants to
be purified. These plants will then remove dirt, biodegradable materials
such as food waste and a number of other pollutants before the water
reaches our waterways. However, most treatment plants can't remove all of
the chemicals that are used in products such as paint thinners or
phosphates that are used in many detergents and these substances end up
passing right through the sewage treatment plant untreated. Other sources
of water pollution include the dirt and litter from the streets that are
washed into storm drains. In most areas these storm drains empty into
,underground pipes that will eventually dump directly into our lakes
.rivers and oceans