Properties of water equal to that of the hydrogen ion (), which gives a pH of 7 at 25 °C. Action of water on rock over long periods of time typically leads to weathering and water erosion, physical processes that convert solid rocks and minerals into soil and sediment, but under some conditions chemical reactions with water occur as well, resulting in metasomatism or mineral hydration, a type of chemical alteration of a rock which produces clay minerals. It also occurs when Portland cement hardens. Water ice can form clathrate compounds, known as clathrate hydrates, with a variety of small molecules that can
Water contamination in Lawrence and Morgan Counties, Alabama statement saying that new tests of the water returned a value of 14 parts per trillion, which is below the EPA health advisory level. However, officials of the water authority are still slightly concerned and continue to push for an activated carbon filter. Perfluorooctanic acid (PFOA) is commonly used as a degradation product with other perfluorinated compounds. PFOA is also used in the production of Teflon, also known as polytetrafluoroethylene, which is often used as a non-stick surface of many cooking items. The chemical often occurs in water systems in industrialized countries. Based on various animal data analysis, the compound