Pediatrics

Child drownings in U.S. pools, spas are on the rise

(HealthDay)—Pool and spa drowning deaths among U.S. children are spiking upwards, and restrictions related to the COVID pandemic may also mean that fewer kids are getting the swimming lessons that might keep them safe, ...

Diseases, Conditions, Syndromes

Speech droplets drive transmission of SARS-CoV-2

A new review published in the Journal of Internal Medicine indicates that unmasked speech in confined spaces poses the greatest risk of spreading SARS-CoV-2, the virus that causes COVID-19, to others.

Diseases, Conditions, Syndromes

Clean water and toilets for healthy shelters

Regular, standardized assessments of evacuation shelters can help keep people healthy following natural disasters, according to research published by Tohoku University scientists and colleagues in the journal Heliyon. The ...

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Water

Water is a ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Saltwater oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Other water is trapped in ice caps, glaciers, aquifers, or in lakes, sometimes providing fresh water for life on land.

Water moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Winds carry water vapor over land at the same rate as runoff into the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDP per capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70 percent of freshwater is consumed by agriculture.

This text uses material from Wikipedia, licensed under CC BY-SA