FAQs

Bottled water is regulated by the U.S. Food and Drug Administration and by individual states. For general information about bottled water, sources include the International Bottled Water Association and NSF International . Learn More: Water Use - Withdrawals for Bottled Water

Pesticide use in the United States has increased because not only must we supply our exploding population with food, but crops and food are also grown for export to other countries. The United States has become the largest producer of food products in the world, partly owing to our use of modern chemicals (pesticides) to control the insects, weeds, and other organisms that attack food crops. But...

See our map of water hardness (as calcium carbonate) in surface water of the United States. Hardness data (reflecting mostly calcium, plus a little magnesium) for individual drinking-water suppliers is at the EPA Office of Ground Water and Drinking Water website. It is important to note that the U.S. Environmental Protection Agency (EPA) has not set a legal limit or standard for hardness in water...

Volatile organic compounds (VOCs), which are widely used in the manufacture of many products including refrigerants, plastics, adhesives, paints, and petroleum products, have been detected in about one-third of the wells sampled by the National Water-Quality Assessment (NAWQA) Program of the USGS. Chloroform and other trihalomethanes, the most commonly detected compounds, were found in about 9...

When sulfurous, sulfuric, and nitric acids in polluted air and rain react with the calcite in marble and limestone, the calcite dissolves. In exposed areas of buildings and statues, we see roughened surfaces, removal of material, and loss of carved details. Stone surface material may be lost all over or only in spots that are more reactive. You might expect that sheltered areas of stone buildings...

Mine drainage is surface water or groundwater that drains from an active or abandoned mine. In some cases, pyrite (an iron sulfide mineral) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy...

Methane (a gas composed of carbon and hydrogen) is produced two ways: Through biologic decomposition of organic matter at shallow depths. Swamps, landfills, and even shallow bedrock are some settings where this occurs. Methane can also be derived over millions of years by high pressure and high temperature processes that produce fossil fuels deep underground. Examples include coal deposits and oil...