United States National Forest
National Forest is a classification of protected and managed federal lands in the United States. National Forests are forest and woodland areas owned collectively by the American people through the federal government, managed by the United States Forest Service, a division of the United States Department of Agriculture; the National Forest System was created by the Land Revision Act of 1891, signed under the presidency of Benjamin Harrison. It was the result of concerted action by Los Angeles-area businessmen and property owners who were concerned by the harm being done to the watershed of the San Gabriel Mountains by ranchers and miners. Abbot Kinney and forester Theodore Lukens were key spokesmen for the effort. In the United States there are 155 National Forests containing 190 million acres of land; these lands comprise 8.5 percent of the total land area of the United States, an area about the size of Texas. Some 87 percent of National Forest land lies west of the Mississippi River in the mountain ranges of the Western United States.
Alaska has 12 percent of all National Forest lands. The U. S. Forest Service manages all of the United States National Grasslands, around half of the United States National Recreation Areas. There are two distinctly different types of forests within the National Forest system; those east of the Great Plains in the Midwestern and Eastern United States were acquired by the federal government since 1891, may be second growth forests. The land had long been in the private domain and sometimes logged since colonial times, but was purchased by the United States government in order to create new National Forests; those west of the Great Plains in the Western United States, though established since 1891, are on lands with ownership maintained by the federal government since the U. S. acquisition and settling of the American West. These are lands that were kept in the public domain, with the exception of inholdings and donated or exchanged private forest lands. Land management of these areas focuses on conservation, timber harvesting, livestock grazing, watershed protection and recreation.
Unlike national parks and other federal lands managed by the National Park Service, extraction of natural resources from national forests is permitted, in many cases encouraged. However, the first-designated wilderness areas, some of the largest, are on National Forest lands. There are management decision conflicts between conservationists and environmentalists, natural resource extraction companies and lobbies, over the protection and/or use of National Forest lands; these conflicts center on endangered species protection, logging of old-growth forests, intensive clear cut logging, undervalued stumpage fees, mining operations and mining claim laws, logging/mining access road-building within National Forests. Additional conflicts arise from concerns that the grasslands and forest understory are grazed by sheep, and, more rising numbers of elk and mule deer due to loss of predators. Many ski resorts and summer resorts operate on leased land in National Forests. List of U. S. National Forests United States National Grassland National Forests of the United States topics State forest National Forest Management Act of 1976 Protected areas of the United States USDA Forest Service USDA Forest Service - The First Century 100 Years of Federal Forestry
The environmental movement including conservation and green politics, is a diverse scientific and political movement for addressing environmental issues. Environmentalists advocate the sustainable management of resources and stewardship of the environment through changes in public policy and individual behavior. In its recognition of humanity as a participant in ecosystems, the movement is centered on ecology and human rights; the environmental movement is an international movement, represented by a range of organizations, from the large to grassroots and varies from country to country. Due to its large membership and strong beliefs, speculative nature, the environmental movement is not always united in its goals; the movement encompasses some other movements with a more specific focus, such as the climate movement. At its broadest, the movement includes private citizens, religious devotees, scientists, nonprofit organizations and individual advocates. Early interest in the environment was a feature of the Romantic movement in the early 19th century.
The poet William Wordsworth had travelled extensively in the Lake District and wrote that it is a "sort of national property in which every man has a right and interest who has an eye to perceive and a heart to enjoy". The origins of the environmental movement lay in the response to increasing levels of smoke pollution in the atmosphere during the Industrial Revolution; the emergence of great factories and the concomitant immense growth in coal consumption gave rise to an unprecedented level of air pollution in industrial centers. Under increasing political pressure from the urban middle-class, the first large-scale, modern environmental laws came in the form of Britain's Alkali Acts, passed in 1863, to regulate the deleterious air pollution given off by the Leblanc process, used to produce soda ash; the modern conservation movement was first manifested in the forests of India, with the practical application of scientific conservation principles. The conservation ethic that began to evolve included three core principles: that the human activity damaged the environment, that there was a civic duty to maintain the environment for future generations, that scientific, empirically based methods should be applied to ensure this duty was carried out.
Sir James Ranald Martin was prominent in promoting this ideology, publishing many medico-topographical reports that demonstrated the scale of damage wrought through large-scale deforestation and desiccation, lobbying extensively for the institutionalization of forest conservation activities in British India through the establishment of Forest Departments. The Madras Board of Revenue started local conservation efforts in 1842, headed by Alexander Gibson, a professional botanist who systematically adopted a forest conservation program based on scientific principles; this was the first case of state management of forests in the world. The government under Governor-General Lord Dalhousie introduced the first permanent and large-scale forest conservation program in the world in 1855, a model that soon spread to other colonies, as well the United States. In 1860, the Department banned the use shifting cultivation. Dr. Hugh Cleghorn's 1861 manual, The forests and gardens of South India, became the definitive work on the subject and was used by forest assistants in the subcontinent.
Sir Dietrich Brandis joined the British service in 1856 as superintendent of the teak forests of Pegu division in eastern Burma. During that time Burma's teak forests were controlled by militant Karen tribals, he introduced the "taungya" system, in which Karen villagers provided labour for clearing and weeding teak plantations. He helped establish research and training institutions; the Imperial Forestry School at Dehradun was founded by him. The late 19th century saw the formation of the first wildlife conservation societies; the zoologist Alfred Newton published a series of investigations into the Desirability of establishing a'Close-time' for the preservation of indigenous animals between 1872 and 1903. His advocacy for legislation to protect animals from hunting during the mating season led to the formation of the Plumage League in 1889; the society acted as a protest group campaigning against the use of great crested grebe and kittiwake skins and feathers in fur clothing. The Society attracted growing support from the suburban middle-classes, influenced the passage of the Sea Birds Preservation Act in 1869 as the first nature protection law in the world.
For most of the century from 1850 to 1950, the primary environmental cause was the mitigation of air pollution. The Coal Smoke Abatement Society was formed in 1898 making it one of the oldest environmental NGOs, it was founded by artist Sir William Blake Richmond, frustrated with the pall cast by coal smoke. Although there were earlier pieces of legislation, the Public Health Act 1875 required all furnaces and fireplaces to consume their own smoke. Systematic and general efforts on behalf of the environment only began in the late 19th century. Starting with the formation of the Commons Preservation Society in 1865, the movement championed rural preservation against the encroachments of industrialisation. Robert Hunter, solicitor for the society, worked with Hardwicke Rawnsley, Octavia Hill, and
Green Day is an American rock band formed in 1986 by lead vocalist and guitarist Billie Joe Armstrong and bassist Mike Dirnt. For much of the band's career, they have been a trio with drummer Tré Cool, who replaced John Kiffmeyer in 1990 prior to the recording of the band's second studio album, Kerplunk. Green Day was part of the punk scene at the DIY 924 Gilman Street club in Berkeley, California; the band's early releases were with the independent record label Lookout! Records. In 1994, their major label debut Dookie, released through Reprise Records, became a breakout success and shipped over 10 million copies in the U. S. Green Day is credited alongside fellow California punk bands including Sublime, Bad Religion, The Offspring and Rancid with popularizing mainstream interest in punk rock in the United States. Though Insomniac and Warning, did not match the success of Dookie and Nimrod reached double platinum and Warning achieved gold status. Green Day's seventh album, American Idiot, a rock opera, found popularity with a younger generation, selling six million copies in the U.
S. 21st Century Breakdown was achieved the band's best chart performance. It was followed by a trilogy of albums, ¡Uno!, ¡Dos! and ¡Tré!, released in September and December 2012 respectively. Green Day's twelfth studio album, Revolution Radio, was released on October 7, 2016 and became their third to debut at number one on the Billboard 200. Green Day has sold more than 85 million records worldwide; the group has won five Grammy Awards: Best Alternative Album for Dookie, Best Rock Album for American Idiot, Record of the Year for "Boulevard of Broken Dreams", Best Rock Album for the second time for 21st Century Breakdown and Best Musical Show Album for American Idiot: The Original Broadway Cast Recording. In 2010, a stage adaptation of American Idiot debuted on Broadway; the musical was nominated for three Tony Awards: Best Musical, Best Scenic Design and Best Lighting Design, losing only the first. In the same year, VH1 ranked Green Day 91st in its list of the "100 Greatest Artists of All Time".
The band was inducted into the Rock and Roll Hall of Fame in their first year of eligibility. In 1986, friends Billie Joe Armstrong and Mike Dirnt, 14 years old at the time, formed a band called Sweet Children; the group's first live performance took place on October 17, 1987, at Rod's Hickory Pit in Vallejo, California. In 1988, Armstrong and Dirnt began working with former Isocracy drummer John Kiffmeyer known as "Al Sobrante". Armstrong cites the band Operation Ivy as a major influence, a group that inspired him to form a band. In 1988, Larry Livermore, owner of Lookout! Records, saw the band signed the group to his label. In 1989, the band recorded its debut extended 1,000 Hours. Before 1,000 Hours was released, the group dropped the name Sweet Children; the band adopted the name Green Day, due to the members' fondness for cannabis. Lookout! Released Green Day's debut studio album, 39/Smooth in early 1990. Green Day recorded two extended plays that year and Sweet Children, the latter of which included older songs that the band had recorded for the Minneapolis independent record label Skene!
Records. In 1991, Lookout! Records re-released 39/Smooth under the name 1,039/Smoothed Out Slappy Hours, added the songs from the band's first two EPs, 1,000 Hours. In late 1990, shortly after the band's first nationwide tour, Kiffmeyer left the East Bay area to attend Humboldt State University in Arcata, California; the Lookouts drummer Tré Cool began filling in as a temporary replacement and Cool's position as Green Day's drummer became permanent, which Kiffmeyer "graciously accepted". The band went on tour for most of 1992 and 1993, played a number of shows overseas in Europe; the band's second studio album Kerplunk sold 50,000 copies in the U. S. Kerplunk's underground success led to a number of major record labels being interested in signing Green Day, the band left Lookout! and signed to Reprise Records after attracting the attention of producer Rob Cavallo. The group was impressed by his work with fellow Californian band The Muffs, remarked that Cavallo "was the only person we could talk to and connect with".
Reflecting on the period, Armstrong told Spin magazine in 1999, "I couldn't go back to the punk scene, whether we were the biggest success in the world or the biggest failure... The only thing I could do was get on my bike and go forward." After signing with Reprise, the band went to work on recording Dookie. Recorded in three weeks, released in February 1994, Dookie became a commercial success, helped by extensive MTV airplay for the videos of the songs "Longview", "Basket Case", "When I Come Around", all of which reached the number one position on the Modern Rock Tracks charts; the album went on to sell over 10 million copies in the US. At a performance on September 9, 1994 at Hatch Memorial Shell in Boston, mayhem broke out during the band's set and by the end of the rampage, 100 people were injured and 45 arrested; the band joined the lineups of both the Lollapalooza festival and Woodstock'94, where the group started an infamous mud fight. During the concert, a security guard mistook bassist Mike Dirnt for a stage-invading fan and punched out some of his teeth.
Viewed by millions by pay-per-view television, the Woodstock 1994 performance further aided Green Day's growing publicity and recognition, helped push its album to eventual diamond status. In 1995, Dookie won the Grammy Awa
Deepwater Horizon oil spill
The Deepwater Horizon oil spill is an industrial disaster that began on April 20, 2010, in the Gulf of Mexico on the BP-operated Macondo Prospect, considered to be the largest marine oil spill in the history of the petroleum industry and estimated to be 8% to 31% larger in volume than the previous largest, the Ixtoc I oil spill in the Gulf of Mexico. The U. S. government estimated the total discharge at 4.9 million barrels. After several failed efforts to contain the flow, the well was declared sealed on September 19, 2010. Reports in early 2012 indicated. A massive response ensued to protect beaches and estuaries from the spreading oil utilizing skimmer ships, floating booms, controlled burns and 1.84 million US gallons of oil dispersant. Due to the months-long spill, along with adverse effects from the response and cleanup activities, extensive damage to marine and wildlife habitats and fishing and tourism industries was reported. In Louisiana, 4,900,000 pounds of oily material was removed from the beaches in 2013, over double the amount collected in 2012.
Oil cleanup crews worked four days a week on 55 miles of Louisiana shoreline throughout 2013. Oil continued to be found as far from the Macondo site as the waters off the Florida Panhandle and Tampa Bay, where scientists said the oil and dispersant mixture is embedded in the sand. In April 2013, it was reported that dolphins and other marine life continued to die in record numbers with infant dolphins dying at six times the normal rate. One study released in 2014 reported that tuna and amberjack that were exposed to oil from the spill developed deformities of the heart and other organs that would be expected to be fatal or at least life-shortening and another study found that cardiotoxicity might have been widespread in animal life exposed to the spill. Numerous investigations explored the causes of record-setting spill; the U. S. government September 2011 report pointed to defective cement on the well, faulting BP, but rig operator Transocean and contractor Halliburton. Earlier in 2011, a White House commission blamed BP and its partners for a series of cost cutting decisions and an inadequate safety system, but concluded that the spill resulted from "systemic" root causes and "absent significant reform in both industry practices and government policies, might well recur".
In November 2012, BP and the United States Department of Justice settled federal criminal charges with BP pleading guilty to 11 counts of manslaughter, two misdemeanors, a felony count of lying to Congress. BP agreed to four years of government monitoring of its safety practices and ethics, the Environmental Protection Agency announced that BP would be temporarily banned from new contracts with the US government. BP and the Department of Justice agreed to a record-setting $4.525 billion in fines and other payments. As of February 2013, criminal and civil settlements and payments to a trust fund had cost the company $42.2 billion. In September 2014, a U. S. District Court judge ruled that BP was responsible for the oil spill because of its gross negligence and reckless conduct. In July 2015, BP agreed to pay $18.7 billion in fines, the largest corporate settlement in U. S. history. The Deepwater Horizon was a 10-year-old semi-submersible, floating, dynamically positioned drilling rig that could operate in waters up to 10,000 feet deep.
Built by South Korean company Hyundai Heavy Industries and owned by Transocean, the rig operated under the Marshallese flag of convenience, was chartered to BP from March 2008 to September 2013. It was drilling a deep exploratory well, 18,360 feet below sea level, in 5,100 feet of water; the well is situated in the Macondo Prospect in Mississippi Canyon Block 252 of the Gulf of Mexico, in the United States' exclusive economic zone. The Macondo well is found 41 miles off the Louisiana coast. BP was the operator and principal developer of the Macondo Prospect with a 65% share, while 25% was owned by Anadarko Petroleum Corporation, 10% by MOEX Offshore 2007, a unit of Mitsui. At 9:45 pm CDT, on April 20, 2010, high-pressure methane gas from the well expanded into the drilling riser and rose into the drilling rig, where it ignited and exploded, engulfing the platform. At the time, 126 crew members were on board: seven BP employees, 79 of Transocean, employees of various other companies. Eleven missing workers were never found despite a three-day U.
S. Coast are believed to have died in the explosion. Ninety-four crew members were rescued by lifeboat or helicopter, 17 of whom were treated for injuries; the Deepwater Horizon sank on the morning of April 22, 2010. The oil leak was discovered on the afternoon of April 22, 2010 when a large oil slick began to spread at the former rig site; the oil flowed for 87 days. BP estimated a flow rate of 1,000 to 5,000 barrels per day; the Flow Rate Technical Group estimated. The total estimated volume of leaked oil approximated 4.9 million barrels with plus or minus 10% uncertainty, including oil, collected, making it the world's largest accidental spill. BP challenged the higher figure. Internal emails released in 2013 showed that one BP employee had estimates that matched those of the FRTG, shared the data with supervisors, but BP continued with their lower number; the company
Renewable energy is energy, collected from renewable resources, which are replenished on a human timescale, such as sunlight, rain, tides and geothermal heat. Renewable energy provides energy in four important areas: electricity generation and water heating/cooling and rural energy services. Based on REN21's 2017 report, renewables contributed 19.3% to humans' global energy consumption and 24.5% to their generation of electricity in 2015 and 2016, respectively. This energy consumption is divided as 8.9% coming from traditional biomass, 4.2% as heat energy, 3.9% from hydroelectricity and the remaining 2.2% is electricity from wind, solar and other forms of biomass. Worldwide investments in renewable technologies amounted to more than US$286 billion in 2015. Globally, there are an estimated 7.7 million jobs associated with the renewable energy industries, with solar photovoltaics being the largest renewable employer. Renewable energy systems are becoming more efficient and cheaper and their share of total energy consumption is increasing.
As of 2015 worldwide, more than half of all new electricity capacity installed was renewable. Growth in consumption of coal and oil could end by 2020 due to increased uptake of renewables and natural gas. At the national level, at least 30 nations around the world have renewable energy contributing more than 20 percent of energy supply. National renewable energy markets are projected to continue to grow in the coming decade and beyond; some places and at least two countries and Norway, generate all their electricity using renewable energy and many other countries have the set a goal to reach 100% renewable energy in the future. At least 47 nations around the world have over 50 percent of electricity from renewable resources. Renewable energy resources exist over wide geographical areas, in contrast to fossil fuels, which are concentrated in a limited number of countries. Rapid deployment of renewable energy and energy efficiency technologies is resulting in significant energy security, climate change mitigation, economic benefits.
In international public opinion surveys there is strong support for promoting renewable sources such as solar power and wind power. While many renewable energy projects are large-scale, renewable technologies are suited to rural and remote areas and developing countries, where energy is crucial in human development; as most of renewable energy technologies provide electricity, renewable energy deployment is applied in conjunction with further electrification, which has several benefits: electricity can be converted to heat, can be converted into mechanical energy with high efficiency, is clean at the point of consumption. In addition, electrification with renewable energy is more efficient and therefore leads to significant reductions in primary energy requirements, because most renewable energy technologies do not need a thermodynamic cycle with high losses. Renewable energy flows involve natural phenomena such as sunlight, tides, plant growth, geothermal heat, as the International Energy Agency explains: Renewable energy is derived from natural processes that are replenished constantly.
In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, ocean, biomass, geothermal resources, biofuels and hydrogen derived from renewable resources. Renewable energy resources and significant opportunities for energy efficiency exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. Rapid deployment of renewable energy and energy efficiency, technological diversification of energy sources, would result in significant energy security and economic benefits, it would reduce environmental pollution such as air pollution caused by burning of fossil fuels and improve public health, reduce premature mortalities due to pollution and save associated health costs that amount to several hundred billion dollars annually only in the United States. Renewable energy sources, that derive their energy from the sun, either directly or indirectly, such as hydro and wind, are expected to be capable of supplying humanity energy for another 1 billion years, at which point the predicted increase in heat from the sun is expected to make the surface of the earth too hot for liquid water to exist.
Climate change and global warming concerns, coupled with high oil prices, peak oil, increasing government support, are driving increasing renewable energy legislation and commercialization. New government spending and policies helped the industry weather the global financial crisis better than many other sectors. According to a 2011 projection by the International Energy Agency, solar power generators may produce most of the world's electricity within 50 years, reducing the emissions of greenhouse gases that harm the environment; as of 2011, small solar PV systems provide electricity to a few million households, micro-hydro configured into mini-grids serves many more. Over 44 million households use biogas made in household-scale digesters for lighting and/or cooking, more than 166 million households rely on a new generation of more-efficient biomass cookstoves. United Nations' Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity.
At the national level, at least 30 nations around the world have renewable energy contributing more than 20% of energy supply. Na
Salmon is the common name for several species of ray-finned fish in the family Salmonidae. Other fish in the same family include trout, char and whitefish. Salmon are native to tributaries of the North Pacific Ocean. Many species of salmon have been introduced into non-native environments such as the Great Lakes of North America and Patagonia in South America. Salmon are intensively farmed in many parts of the world. Salmon are anadromous: they hatch in fresh water, migrate to the ocean return to fresh water to reproduce. However, populations of several species are restricted to fresh water through their lives. Folklore has it. Tracking studies have shown this to be true. A portion of a returning salmon run may spawn in different freshwater systems. Homing behavior has been shown to depend on olfactory memory. Salmon date back to the Neogene; the term "salmon" comes from the Latin salmo, which in turn might have originated from salire, meaning "to leap". The nine commercially important species of salmon occur in two genera.
The genus Salmo contains the Atlantic salmon, found in the north Atlantic, as well as many species named trout. The genus Oncorhynchus contains eight species which occur only in the North Pacific; as a group, these are known as Pacific salmon. Chinook salmon have been introduced in New Patagonia. Coho, freshwater sockeye, Atlantic salmon have been established in Patagonia, as well. † Both the Salmo and Oncorhynchus genera contain a number of species referred to as trout. Within Salmo, additional minor taxa have been called salmon in English, i.e. the Adriatic salmon and Black Sea salmon. The steelhead anadromous form of the rainbow trout migrates to sea, but it is not termed "salmon". A number of other species have common names which refer to them as being salmon. Of those listed below, the Danube salmon or huchen is a large freshwater salmonid related to the salmon above, but others are marine fishes of the unrelated Perciformes order: Eosalmo driftwoodensis, the oldest known salmon in the fossil record, helps scientists figure how the different species of salmon diverged from a common ancestor.
The British Columbia salmon fossil provides evidence that the divergence between Pacific and Atlantic salmon had not yet occurred 40 million years ago. Both the fossil record and analysis of mitochondrial DNA suggest the divergence occurred by 10 to 20 million years ago; this independent evidence from DNA analysis and the fossil record rejects the glacial theory of salmon divergence. Atlantic salmon reproduce in northern rivers on both coasts of the Atlantic Ocean. Landlocked salmon live in a number of lakes in eastern North America and in Northern Europe, for instance in lakes Sebago, Ladoga, Saimaa, Vänern, Winnipesaukee, they are not a different species from the Atlantic salmon, but have independently evolved a non-migratory life cycle, which they maintain when they could access the ocean. Chinook salmon are known in the United States as king salmon or blackmouth salmon, as spring salmon in British Columbia. Chinook are the largest of all Pacific salmon exceeding 14 kg; the name tyee is used in British Columbia to refer to Chinook over 30 pounds, in the Columbia River watershed large Chinook were once referred to as June hogs.
Chinook salmon are known to range as far north as the Mackenzie River and Kugluktuk in the central Canadian arctic, as far south as the Central California coast. Chum salmon are known as dog, keta, or calico salmon in some parts of the US; this species has the widest geographic range of the Pacific species: south to the Sacramento River in California in the eastern Pacific and the island of Kyūshū in the Sea of Japan in the western Pacific. Coho salmon are known in the US as silver salmon; this species is found throughout the coastal waters of Alaska and British Columbia and as far south as Central California. It is now known to occur, albeit infrequently, in the Mackenzie River. Masu salmon or cherry salmon are found only in the western Pacific Ocean in Japan and Russia. A land-locked subspecies known as the Taiwanese salmon or Formosan salmon is found in central Taiwan's Chi Chia Wan Stream. Pink salmon, known as humpies in southeast and southwest Alaska, are found from northern California and Korea, throughout the northern Pacific, from the Mackenzie River in Canada to the Lena River in Siberia in shorter coastal streams.
It is the smallest of the Pacific species, with an average weight of 1.6 to 1.8 kg. Sockeye salmon are known in the US as red salmon; this lake-rearing species is found south as far as the Klamath River in California in the eastern Pacific and northern Hokkaidō island in Japan in the western Pacific and as far north as Bathurst Inlet in the Canadian Arctic in the east and the Anadyr River in Siberia in the west. Although most adult Pacific salmon feed on small fish and squid, sockeye feed on plankton they filter through gill rakers. Kokanee salmon are the land-locked form of sockeye salmon. Danube salmon, or huchen, are the largest permanent freshwater salmonid species. Salmon eggs are laid in freshwater streams at high latitudes; the eggs hatch into alevin or sac fry
Water quality refers to the chemical, physical and radiological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose, it is most used by reference to a set of standards against which compliance achieved through treatment of the water, can be assessed. The most common standards used to assess water quality relate to health of ecosystems, safety of human contact, drinking water. In the setting of standards, agencies make political and technical/scientific decisions about how the water will be used. In the case of natural water bodies, they make some reasonable estimate of pristine conditions. Natural water bodies will vary in response to environmental conditions. Environmental scientists work to understand how these systems function, which in turn helps to identify the sources and fates of contaminants. Environmental lawyers and policymakers work to define legislation with the intention that water is maintained at an appropriate quality for its identified use.
The vast majority of surface water on the Earth is neither toxic. This remains true. Another general perception of water quality is that of a simple property that tells whether water is polluted or not. In fact, water quality is a complex subject, in part because water is a complex medium intrinsically tied to the ecology of the Earth. Industrial and commercial activities are a major cause of water pollution as are runoff from agricultural areas, urban runoff and discharge of treated and untreated sewage; the parameters for water quality are determined by the intended use. Work in the area of water quality tends to be focused on water, treated for human consumption, industrial use, or in the environment. Contaminants that may be in untreated water include microorganisms such as viruses and bacteria. Water quality depends on the local geology and ecosystem, as well as human uses such as sewage dispersion, industrial pollution, use of water bodies as a heat sink, overuse; the United States Environmental Protection Agency limits the amounts of certain contaminants in tap water provided by US public water systems.
The Safe Drinking Water Act authorizes EPA to issue two types of standards: primary standards regulate substances that affect human health. The U. S. Food and Drug Administration regulations establish limits for contaminants in bottled water that must provide the same protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants; the presence of these contaminants does not indicate that the water poses a health risk. In urbanized areas around the world, water purification technology is used in municipal water systems to remove contaminants from the source water before it is distributed to homes, businesses and other recipients. Water drawn directly from a stream, lake, or aquifer and that has no treatment will be of uncertain quality. Dissolved minerals may affect suitability of water for a range of domestic purposes; the most familiar of these is the presence of ions of calcium and magnesium which interfere with the cleaning action of soap, can form hard sulfate and soft carbonate deposits in water heaters or boilers.
Hard water may be softened to remove these ions. The softening process substitutes sodium cations. Hard water may be preferable to soft water for human consumption, since health problems have been associated with excess sodium and with calcium and magnesium deficiencies. Softening may increase cleaning effectiveness. Various industries' wastes and effluents can pollute the water quality in receiving bodies of water. Environmental water quality called ambient water quality, relates to water bodies such as lakes and oceans. Water quality standards for surface waters vary due to different environmental conditions and intended human uses. Toxic substances and high populations of certain microorganisms can present a health hazard for non-drinking purposes such as irrigation, fishing, rafting and industrial uses; these conditions may affect wildlife, which use the water for drinking or as a habitat. Modern water quality laws specify protection of fisheries and recreational use and require, as a minimum, retention of current quality standards.
There is some desire among the public to return water bodies to pristine, or pre-industrial conditions. Most current environmental laws focus on the designation of particular uses of a water body. In some countries these designations allow for some water contamination as long as the particular type of contamination is not harmful to the designated uses. Given the landscape changes in the watersheds of many freshwater bodies, returning to pristine conditions would be a significant challenge. In these cases, environmental scientists focus on achieving goals for maintaining healthy ecosystems and may concentrate on the protection of populations of endangered species and protecting human health; the complexity of water quality as a subject is reflected in the many types of measu