Drinking water
Drinking water is a vital resource essential for human health and well-being, yet access to safe drinking water remains a significant global challenge. Millions suffer from water scarcity, with many losing their lives due to contaminated supplies resulting from unsanitary conditions. Even in developed nations, drinking water can be tainted with toxic elements like lead and arsenic, as well as harmful microorganisms. The United Nations has recognized clean water as a universal human right, yet billions still lack reliable access to safe water and sanitation services. Factors such as urbanization, pollution, climate change, and rapid population growth exacerbate the problem, potentially leading to severe water shortages for billions by 2050. Treatment methods for unsafe water include chlorination and other purification techniques, as well as groundwater extraction, which is less contaminated but increasingly strained by overuse. Innovations like desalination, rainwater harvesting, and advanced wastewater treatment technologies are being explored to augment water supplies. Efforts are underway globally to improve access to clean drinking water, with community projects and portable filtration systems like Lifestraw offering hope in underserved regions.
Subject Terms
Drinking water
The term "drinking water" refers to water supplies for human consumption. Water is essential for human life, and many important social and economic systems are rooted in this universal basic need. However, many areas of the world lack sufficient safe drinking water to support their populations. International, national, and local efforts have been undertaken to conserve existing water supplies, to clean up polluted water supplies with appropriate treatment, and to find new ways of distributing safe drinking water to those who need it.
Overview
Water consumption is a fundamental need of the human body. Indeed, the average human body consists of about 55 to 65 percent water. Optimal daily water intake can vary substantially between individuals and in different environmental conditions (particularly related to heat and humidity), but many experts recommend at least 2 liters per day for most adults.
Despite the universal importance of drinking water, many people lack access to safe drinking water (also called "potable water"). While water is abundant on Earth, about 97 percent of all water on the planet is found in the oceans; this seawater contains too much salt for humans to drink safely. An additional 2.5 percent of water on Earth is considered unavailable due to its location (such as frozen in ice caps or glaciers, or in vaporous form in the atmosphere) or extensive pollution. This leaves just 0.5 of the planet's water for human consumption and all other uses of freshwater, such as animal consumption and crop irrigation. Many water supplies are naturally replenished through the hydrologic cycle, but competition for water resources can still be substantial.
Millions of people die each year because of a lack of drinking water or because their water supplies are contaminated owing to unsanitary conditions. Even in developed countries where water supplies are sufficient, drinking water may contain dangerous contaminants, including such toxic chemicals as lead and arsenic, harmful microorganisms, and even radioactive compounds such as radon.
In 2010, the United Nations declared clean water a universal human right. Nevertheless, according to a report by the World Health Organization (WHO) and the United Nations (UN) Children's Fund, by the early 2020s some 2 billion people worldwide still lacked access to safe drinking water at home, and 3.6 billion did not have safely managed water sanitation services. Public health officials and other experts have identified several major obstacles to the goal of ensuring access to safe water and sanitation for all people in the world. These include complex, interrelated factors such as urbanization, pollution, climate change, and population growth.
Quality, Accessibility, and Regulation
Most problems with water quality involve contamination with disease-causing (pathogenic) microorganisms. Safe, clean drinking water is free of all pathogenic microbes. A number of dangerous microorganisms can be transmitted by water, including viruses (for example, hepatitis A), bacteria (Salmonella and Vibrio cholera), protozoa (Giardia, Cryptosporidium, and Entamoeba), and parasitic worms, or helminths (Ascaris lumbricoides). Pollution and microbial contamination make the waters of most rivers, lakes, and ponds (surface water) unfit for human consumption without prior purifying treatment. The most common method of treating surface water to produce safe drinking water is disinfection by chlorination. Chloramines and ultraviolet light are also used for treatment.
A sufficient quantity of good-quality drinking water exists to satisfy the needs of all human beings on the planet, but the water is not distributed in such a way that it reaches populations in all parts of the world. Population growth also has impacts on drinking-water resources, even in regions with large supplies of water. In many developing countries, people have no choice but to use water that is polluted with various wastes—including human sewage, animal excrement, and a variety of pathogenic microorganisms—because no water treatment systems are in place.
In many locations, drinking water is obtained from groundwater sources. Groundwater—water found beneath the ground surface in soil and rock spaces—can generally be used for drinking with minimal treatment because it has already been purified by passing through soil. Wells must be dug to reach this water. In many parts of the world, groundwater usage is increasingly outpacing the rate of groundwater replacement.
Several countries have introduced regulations intended to ensure the good quality of drinking water. In the United States, the Environmental Protection Agency (EPA) sets standards for drinking water under the 1974 Safe Drinking Water Act. These standards cover some ninety-four possible contaminants, including biological and chemical substances. For example, the EPA sets the acceptable number of microorganisms per 1 milliliter (0.034 ounces) of water at fewer than ten, and water that is considered drinkable can contain no coliform bacteria. However, many pharmaceutical contaminants are not covered by the EPA's regulations.
Efforts to Increase Supply
The need to obtain more drinking water in some regions has led to increased use of desalination technologies as well as increasing emphasis on the conservation of existing water supplies. The desalination of ocean water produces billions of gallons of drinking water per day around the world, but this process can have some negative environmental impacts, such as thermal pollution and damage to shoreline ecosystems.
Water conservation is the most cost-effective way to reduce demand for drinking water. Both local and national governments in many nations have introduced regulations and programs aimed at encouraging water conservation on the level of individual households; among the areas targeted for reduced usage of drinking water supplies have been lawn maintenance and toilet flushing. The practice of rainwater harvesting is encouraged in some areas, and some governments have instituted strict compulsory water metering to raise awareness of the need to conserve water.
Another option for increasing supplies of drinking water is the restoration of municipal and industrial wastewater to drinkable quality. Using technologies such as membrane bioreactor treatment (which involves treating wastewater with certain types of microorganisms and then putting it through microfiltration, followed by disinfection with ultraviolet light), communities can turn their own wastewater into drinking water. Efforts are also being made globally to find ways to provide clean drinking water to populations in need. Solar and wind power are being used to power filtering and purification systems. Receptacles such as the Warka Water Tower in Ethiopia and the Fog Harvester in Morocco have provided entire villages with access to clean drinking water. Finally, Lifestraw is a portable water filtration system that has revolutionized the way developing nations endure access to clean drinking water.
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