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
Nonpoint source water pollution regulations in the United States is ingested into the body. Nonpoint source pollution can often have toxic contaminants and chemicals present in the water. Additionally, there can be both bacteria and viruses (aka pathogens) found in the water. Effluent from nonpoint sources may include toxic contaminates and chemical compounds including heavy metals like lead, mercury, zinc, and cadmium, organics like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), and other substances resistant to breakdown . There are many health effects associated with many of these toxic substances. Pathogens are bacteria and viruses that can be found in water and cause diseases in humans. Pathogens found