Hi Ian,
This is a good question. Although we have easy access to freshwater in most of the US, water is still a very important and very valuable resource. We should use it wisely, and manage it very carefully.
Many freshwater lakes, streams, and ponds are polluted. The causes of pollution depend on many different factors. These factors vary in different parts of the world.
The pollutants can cause algae
to grow quickly. These 'blooms' of algae may produce toxins that harm other life in
the river. When the algae die and decay, this uses up much of the oxygen in the stream. Without enough oxygen in the water, invertebrates
and fish will suffocate
.
Further downstream, more and more pollutants get washed into the river and their harmful effects are even greater. In the Gulf of Mexico, there is a large area of water called the "Dead Zone." It is so low in oxygen that it can't support life at all!
In some developing countries, a major problem is the building of large towns close to freshwater sources. The polluted water produced by homes and industries does not get properly treated. And this dirty water gets cycled back into the water system.
Water
isn't just used locally. We extract a lot of water from rivers and lakes around the world for our own needs. We use water for
washing and drinking, to grow food, to generate energy
, and for many other useful purposes. Since this leaves a smaller amount
of water in these ecosystems, pollution will affect the ecosystem more.
Scientists are studying those areas that are at greatest threat. We hope to make the public more aware of the problems of water pollution so that local and national governments will develop better policies for water management.
As an individual, there are many things that you can do to help keep our water safe and clean. Check out Be a Water Saver below for ideas.
I hope this answers your question. And I hope you'll continue to investigate how water is used in your local region. We can all help keep rivers and lakes clean, so that we can keep enjoying them for a long time to come.