Water - it's all around us. It's inside our cells, coursing throughour veins, and sustaining life for organisms everywhere. It'sunderground, on the surface, and in the air. But while water may seemunending in supply, the statistics suggest otherwise. Only 2.5% of allwater on Earth is fresh water, and only 0.01% of all water is freshwater that is easily attainable by humans from rivers, lakes, andshallow groundwater. Many nations are experiencing severe shortages inwater in the modern world and a third of the global population lives inareas with moderate to high levels of water stress. In fact, waterscarcity is often cited as one of the top problems facing humankind inthis century and may likely be the single greatest source ofinternational conflict over the next 50 years as nations vie for controlof shared waterways. At the same time, many rivers and lakes aresuffering from eutrophication, sewage pollution, and contamination withharmful chemicals.
If we are to support the billions of people currently alive and thosein the future, we must drastically change our outlook on water. We mustuse less, improve the efficiency of the water we use, and reducepollution loads to waterways. This module will examine water use inyour home and enable you to investigate ways to lessen your overallwater usage. It will also familiarize you with the processes used toclean water before and after use.