GEF

Unit 1  |  Why Water Matters 29 under threat, including the river delta marshlands of the Colorado, Mississippi, and Nile Rivers, and the rapidly shrink- ing Aral Sea in southwest Asia. In addition to meeting the current and future water needs of people, an essential com- ponent of sustainability is the rehabilitation and protection of these vital ecosystems. RIVER DELTA A landform created by sediment deposited by a river flowing into an ocean, sea, desert, estuary, lake, or another river. WATER CONCEPTS: BOTTLED WATER Partially because of perceived concerns over water quality in public systems, many people in developed countries regularly purchase bottled water. While some bottled water is derived from springs and other natural sources, a surprisingly large percentage is actually purified or even untreated tap water. Independent studies of popular bottled water brands have revealed that many contain pollutants such as chlorine byproducts, trace pharmaceuticals, arsenic, and even radioactive isotopes. San Francisco and other cities have banned city employees from buying bottled water using public funds, citing the problem of waste from plastic bottles and the expense. However, bottled water sales are booming, approaching $12 billion in the U.S. alone. In countries that have high-quality public drinking water, sustainability advocates argue that relying on bottled water represents a significant waste of money and resources. More and more people are choosing to forgo bottled water and carry their own reusable water bottles instead.