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However, the development of the Newton hardware/software platform was canceled by Steve Jobs on February 27, 1998, so the InterConnect port, while itself very advanced, can only be used to connect a serial dongle. A prototype multi-purpose InterConnect device containing serial, audio in, audio out, and other ports was also discovered. In addition, all Newton devices have infrared connectivity, initially only the Sharp ASK protocol, but later also IrDA, though the Sharp ASK protocol was kept in for compatibility reasons. Unlike the Palm Pilot, all Newton devices are equipped with a standard PC Card expansion slot (two on the 2000/2100). This allows native modem and even Ethernet connectivity; Newton users have also written drivers for 802.11b wireless networking cards and ATA-type flash memory cards (including the popular CompactFlash format), as well as for Bluetooth cards. Newton can also dial a phone number through the built-in speaker of the Newton device by simply holding a telephone handset up to the speaker and transmitting the appropriate tones.
Newton can also dial a phone number through the built-in speaker of the Newton device by simply holding a telephone handset up to the speaker and transmitting the appropriate tones. Fax and printing support is also built in at the operating system level, although it requires peripherals such as parallel adapters, PCMCIA cards, or serial modems, the most notable of which is the lightweight Newton Fax Modem released by Apple in 1993. It is powered by 2 AA batteries, and can also be used with a power adapter. It provides data transfer at 2,400 bit/s, and can also send and receive fax messages at 9,600 and 4,800 bit/s respectively. Power options. The original Apple MessagePad and MessagePad 100 used four AAA batteries. They were eventually replaced by AA batteries with the release of the Apple MessagePad 110. The use of 4 AA NiCd (MessagePad 110, 120 and 130) and 4x AA NiMH cells (MP2x00 series, eMate 300) give a runtime of up to 30 hours (MP2100 with two 20 MB Linear Flash memory PC Cards, no backlight usage) and up to 24 hours with backlight on. While adding more weight to the handheld Newton devices than AAA batteries or custom battery packs, the choice of an easily replaceable/rechargeable cell format gives the user a still unsurpassed runtime and flexibility of power supply. This, together with the flash memory used as internal storage starting with the Apple MessagePad 120 (if all cells lost their power, no data was lost due to the non-volatility of this storage), gave birth to the slogan "Newton never dies, it only gets new batteries".
Later efforts and improvements. The Apple MessagePad 2000/2100, with a vastly improved handwriting recognition system, 162 MHz StrongARM SA-110 RISC processor, Newton OS 2.1, and a better, clearer, backlit screen, attracted critical plaudits. eMate 300. The eMate 300 was a Newton device in a laptop form factor offered to schools in 1997 as an inexpensive ($799 US, originally sold to education markets only) and durable computer for classroom use. However, in order to achieve its low price, the eMate 300 did not have all the speed and features of the contemporary MessagePad equivalent, the MessagePad 2000. The eMate was cancelled along with the rest of the Newton products in 1998. It is the only Newton device to use the ARM710 microprocessor (running at 25 MHz), have an integrated keyboard, use Newton OS 2.2 (officially numbered 2.1), and its batteries are officially irreplaceable, although several users replaced them with longer-lasting ones without any damage to the eMate hardware whatsoever. Prototypes. Many prototypes of additional Newton devices were spotted. Most notable was a Newton tablet or "slate", a large, flat screen that could be written on. Others included a "Kids Newton" with side handgrips and buttons, "VideoPads" which would have incorporated a video camera and screen on their flip-top covers for two-way communications, the "Mini 2000" which would have been very similar to a Palm Pilot, and the NewtonPhone developed by Siemens, which incorporated a handset and a keyboard.
Market reception. Fourteen months after Sculley demoed it at the May 1992, Chicago CES, the MessagePad was first offered for sale on August 2, 1993, at the Boston Macworld Expo. The hottest item at the show, it cost $900. 50,000 MessagePads were sold in the device's first three months on the market. The original Apple MessagePad and MessagePad 100 were limited by the very short lifetime of their inadequate AAA batteries. Later versions of Newton OS offered improved handwriting recognition, quite possibly a leading reason for the continued popularity of the devices among Newton users. Even given the age of the hardware and software, Newtons still demand a sale price on the used market far greater than that of comparatively aged PDAs produced by other companies. In 2006, CNET compared an Apple MessagePad 2000 to a Samsung Q1, and the Newton was declared better. In 2009, CNET compared an Apple MessagePad 2000 to an iPhone 3GS, and the Newton was declared more innovative at its time of release. A chain of dedicated Newton-only stores called Newton Source, independently run by Stephen Elms, existed from 1994 until 1998. Locations included New York, Los Angeles, San Francisco, Chicago and Boston. The Westwood Village, California, near UCLA featured the trademark red and yellow light bulb Newton logo in neon. The stores provided an informative educational venue to learn about the Newton platform in a hands on relaxed fashion. The stores had no traditional computer retail counters and featured oval desktops where interested users could become intimately involved with the Newton product range. The stores were a model for the later Apple Stores.
Newton device models. Notes: The eMate 300 actually has ROM chips silk screened with 2.2 on them. Stephanie Mak on her website discusses this: If one removes all patches to the eMate 300 (by replacing the ROM chip, and then putting in the original one again, as the eMate and the MessagePad 2000/2100 devices erase their memory completely after replacing the chip), the result will be the Newton OS saying that this is version 2.2.00. Also, the Original MessagePad and the MessagePad 100 share the same model number, as they only differ in the ROM chip version. (The OMP has OS versions 1.0 to 1.05, or 1.10 to 1.11, while the MP100 has 1.3 that can be upgraded with various patches.) Third party licenses. The Newton OS was also licensed to a number of third-party developers including Sharp and Motorola who developed additional PDA devices based on the Newton platform. Motorola added wireless connectivity, as well as made a unique two-part design, and shipped additional software with its Newton device, called the Marco. Sharp developed a line of Newton devices called the ExpertPad PI-7000/7100; those were the same as Apple's MessagePad and MessagePad 100, the only difference is the physical design (the ExpertPads feature a screen lid, which Apple added in 1994 with the release of the MessagePad 110) and the naming.
Other uses. There were a number of projects that used the Newton as a portable information device in cultural settings such as museums. For example, Visible Interactive created a walking tour in San Francisco's Chinatown but the most significant effort took place in Malaysia at the Petronas Discovery Center, known as Petrosains. In 1995, an exhibit design firm, DMCD Inc., was awarded the contract to design a new science museum in the Petronas Towers in Kuala Lumpur. A major factor in the award was the concept that visitors would use a Newton device to access additional information, find out where they were in the museum, listen to audio, see animations, control robots and other media, and to bookmark information for printout at the end of the exhibit. The device became known as the ARIF, a Malay word for "wise man" or "seer" and it was also an acronym for A Resourceful Informative Friend. Some 400 ARIFS were installed and over 300 are still in use today. The development of the ARIF system was extremely complex and required a team of hardware and software engineers, designers, and writers. ARIF is an ancestor of the PDA systems used in museums today and it boasted features that have not been attempted since.
Anyway & Company firm was involved with the Petronas Discovery Center project back in 1998 and NDAs were signed which prevents getting to know more information about this project. It was confirmed that they purchased of MP2000u or MP2100's by this firm on the behalf of the project under the name of "Petrosains Project Account". By 1998 they had invested heavily into the R&D of this project with the Newton at the center. After Apple officially cancelled the Newton in 1998 they had to acquire as many Newtons as possible for this project. It was estimated initially 1000 Newtons, but later readjusted the figure to possibly 750 Newtons. They placed an “Internet Call” for Newtons. They purchased them in large and small quantities. The Newton was also used in healthcare applications, for example in collecting data directly from patients. Newtons were used as electronic diaries, with patients entering their symptoms and other information concerning their health status on a daily basis. The compact size of the device and its ease of use made it possible for the electronic diaries to be carried around and used in the patients' everyday life setting. This was an early example of electronic patient-reported outcomes (ePRO).
A. E. van Vogt Alfred Elton van Vogt ( ; April 26, 1912 – January 26, 2000) was a Canadian-born American science fiction writer. His fragmented, bizarre narrative style influenced later science fiction writers, notably Philip K. Dick. He was one of the most popular and influential practitioners of science fiction in the mid-twentieth century, the genre's so-called Golden Age, and one of the most complex. The Science Fiction Writers of America named him their 14th Grand Master in 1995 (presented 1996). Early life. Alfred Vogt (both "Elton" and "van" were added much later) was born on April 26, 1912, on his grandparents' farm in Edenburg, Manitoba, a tiny (and now defunct) Russian Mennonite community east of Gretna, Manitoba, Canada, in the Mennonite West Reserve. He was the third of six children born to Heinrich "Henry" Vogt and Aganetha "Agnes" Vogt (née Buhr), both of whom were born in Manitoba and grew up in heavily immigrant communities. Until he was four, van Vogt spoke only Plautdietsch at home. For the first dozen or so years of his life, van Vogt's father, Henry Vogt, a lawyer, moved his family several times within central Canada, moving to Neville, Saskatchewan; Morden, Manitoba; and finally Winnipeg, Manitoba. Alfred Vogt found these moves difficult, later remarking:
By the 1920s, living in Winnipeg, father Henry worked as an agent for a steamship company, but the stock market crash of 1929 proved financially disastrous, and the family could not afford to send Alfred to college. During his teen years, Alfred worked as a farmhand and a truck driver, and by the age of 19, he was working in Ottawa for the Canadian Census Bureau. In "the dark days of '31 and '32," van Vogt took a correspondence course in writing from the Palmer Institute of Authorship. He sold his first story in fall 1932. His early published works were stories in the true confession style of magazines such as "True Story". Most of these stories were published anonymously, with the first-person narratives allegedly being written by people (often women) in extraordinary, emotional, and life-changing circumstances. After a year in Ottawa, he moved back to Winnipeg, where he sold newspaper advertising space and continued to write. While continuing to pen melodramatic "true confessions" stories through 1937, he also began writing short radio dramas for local radio station CKY, as well as conducting interviews published in trade magazines. He added the middle name "Elton" at some point in the mid-1930s, and at least one confessional story (1937's "To Be His Keeper") was sold to the "Toronto Star", who misspelled his name "Alfred Alton Bogt" in the byline. Shortly thereafter, he added the "van" to his surname, and from that point forward he used the name "A. E. van Vogt" both personally and professionally.
Career. By 1938, van Vogt decided to switch to writing science fiction, a genre he enjoyed reading. He was inspired by the August 1938 issue of "Astounding Science Fiction," which he picked up at a newsstand. John W. Campbell's novelette "Who Goes There?" (later adapted into "The Thing from Another World" and "The Thing") inspired van Vogt to write "Vault of the Beast", which he submitted to that same magazine. Campbell, who edited "Astounding" (and had written the story under a pseudonym), sent van Vogt a rejection letter in which Campbell encouraged van Vogt to try again. Van Vogt sent another story, entitled "Black Destroyer", which was accepted. It featured a fierce, carnivorous alien stalking the crew of a spaceship, and served as the inspiration for multiple science fiction movies, including "Alien" (1979). A revised version of "Vault of the Beast" was published in 1940. While still living in Winnipeg, in 1939 van Vogt married Edna Mayne Hull, a fellow Manitoban. Hull, who had previously worked as a private secretary, went on to act as van Vogt's typist, and was credited with writing several SF stories of her own throughout the early 1940s.
The outbreak of World War II in September 1939 caused a change in van Vogt's circumstances. Ineligible for military service due to his poor eyesight, he accepted a clerking job with the Canadian Department of National Defence. This necessitated a move back to Ottawa, where he and his wife stayed for the next year and a half. Meanwhile, his writing career continued. "Discord in Scarlet" was van Vogt's second story to be published, also appearing as the cover story. It was accompanied by interior illustrations created by Frank Kramer and Paul Orban. (Van Vogt and Kramer thus debuted in the issue of "Astounding" that is sometimes identified as the start of the Golden Age of Science Fiction.) Among his most famous works of this era, "Far Centaurus" appeared in the January 1944 edition of "Astounding". Van Vogt's first completed novel, and one of his most famous, is "Slan" (Arkham House, 1946), which Campbell serialized in "Astounding" (September to December 1940). Using what became one of van Vogt's recurring themes, it told the story of a nine-year-old superman living in a world in which his kind are slain by "Homo sapiens".
Others saw van Vogt's talent from his first story, and in May 1941 van Vogt decided to become a full-time writer, quitting his job at the Canadian Department of National Defence. Freed from the necessity of living in Ottawa, he and his wife lived for a time in the Gatineau region of Quebec before moving to Toronto in the fall of 1941. Prolific throughout this period, van Vogt wrote many of his more famous short stories and novels in the years from 1941 through 1944. The novels "The Book of Ptath" and "The Weapon Makers" both appeared in magazines in serial form during this period; they were later published in book form after World War II. As well, several (though not all) of the stories that were compiled to make up the novels "The Weapon Shops of Isher", "The Mixed Men" and "The War Against the Rull" were published during this time. California and post-war writing (1944–1950). In November 1944, van Vogt and Hull moved to Hollywood; van Vogt would spend the rest of his life in California. He had been using the name "A. E. van Vogt" in his public life for several years, and as part of the process of obtaining American citizenship in 1945 he finally and formally changed his legal name from Alfred Vogt to Alfred Elton van Vogt. To his friends in the California science fiction community, he was known as "Van".
Method and themes. Van Vogt systematized his writing method, using scenes of 800 words or so where a new complication was added or something resolved. Several of his stories hinge on temporal conundra, a favorite theme. He stated that he acquired many of his writing techniques from three books: "Narrative Technique" by Thomas Uzzell, "The Only Two Ways to Write a Story" by John Gallishaw, and "Twenty Problems of the Fiction Writer" by Gallishaw. He also claimed many of his ideas came from dreams; throughout his writing life he arranged to be awakened every 90 minutes during his sleep period so he could write down his dreams. Van Vogt was also always interested in the idea of all-encompassing systems of knowledge (akin to modern meta-systems). The characters in his very first story used a system called "Nexialism" to analyze the alien's behavior. Around this time, he became particularly interested in the general semantics of Alfred Korzybski. He subsequently wrote a novel merging these overarching themes, "The World of Ā", originally serialized in "Astounding" in 1945. Ā (often rendered as "Null-A"), or non-Aristotelian logic, refers to the capacity for, and practice of, using intuitive, inductive reasoning (compare fuzzy logic), rather than reflexive, or conditioned, deductive reasoning. The novel recounts the adventures of an individual living in an apparent Utopia, where those with superior brainpower make up the ruling class... though all is not as it seems. A sequel, "The Players of Ā" (later re-titled "The Pawns of Null-A") was serialized in 1948–49.
At the same time, in his fiction, van Vogt was consistently sympathetic to absolute monarchy as a form of government. This was the case, for instance, in the "Weapon Shop" series, the "Mixed Men" series, and in single stories such as "Heir Apparent" (1945), whose protagonist was described as a "benevolent dictator". These sympathies were the subject of much critical discussion during van Vogt's career, and afterwards. Van Vogt published "Enchanted Village" in the July 1950 issue of "Other Worlds Science Stories". It was reprinted in over 20 collections or anthologies, and appeared many times in translation. Dianetics and fix-ups (1950–1961). In 1950, van Vogt was briefly appointed as head of L. Ron Hubbard's Dianetics operation in California. Van Vogt had first met Hubbard in 1945, and became interested in his theories, which were published shortly thereafter. Dianetics was the secular precursor to Hubbard's Church of Scientology; van Vogt would have no association with Scientology, as he did not approve of its mysticism.
The California Dianetics operation went broke nine months later, but never went bankrupt, due to van Vogt's arrangements with creditors. Shortly afterward, van Vogt and his wife opened their own Dianetics center, partly financed by his writings, until he "signed off" around 1961. From 1951 until 1961, van Vogt's focus was on Dianetics, and no new story ideas flowed from his typewriter. Fix-ups. However, during the 1950s, van Vogt retrospectively patched together many of his previously published stories into novels, sometimes creating new interstitial material to help bridge gaps in the narrative. Van Vogt referred to the resulting books as "fix-ups", a term that entered the vocabulary of science-fiction criticism. When the original stories were closely related this was often successful, although some van Vogt fix-ups featured disparate stories thrown together that bore little relation to each other, generally making for a less coherent plot. One of his best-known (and well-regarded) novels, "The Voyage of the Space Beagle" (1950) was a fix-up of four short stories including "Discord in Scarlet"; it was published in at least five European languages by 1955.
Although Van Vogt averaged a new book title every ten months from 1951 to 1961, none of them were entirely new content; they were all fix-ups, collections of previously published stories, expansions of previously published short stories to novel length, or republications of previous books under new titles and all based on story material written and originally published between 1939 and 1950. Examples include "The Weapon Shops of Isher" (1951), "The Mixed Men" (1952), "The War Against the Rull" (1959), and the two "Clane" novels, "Empire of the Atom" (1957) and "The Wizard of Linn" (1962), which were inspired (like Asimov's Foundation series) by Roman imperial history; specifically, as Damon Knight wrote, the plot of "Empire of the Atom" was "lifted almost bodily" from that of Robert Graves' "I, Claudius". (Also, one non-fiction work, "The Hypnotism Handbook", appeared in 1956, though it had apparently been written much earlier.) After more than a decade of running their Dianetics center, Hull and van Vogt closed it in 1961. Nevertheless, van Vogt maintained his association with the organization and was still president of the Californian Association of Dianetic Auditors into the 1980s.
Return to writing and later career (1962–1986). Though the constant re-packaging of his older work meant that he had never really been away from the book publishing world, van Vogt had not published any wholly new fiction for almost 12 years when he decided to return to writing in 1962. He did not return immediately to science fiction, but instead wrote the only mainstream, non-sf novel of his career. Van Vogt was profoundly affected by revelations of totalitarian police states that emerged after World War II. Accordingly, he wrote a mainstream novel that he set in Communist China, "The Violent Man" (1962). Van Vogt explained that to research this book he had read 100 books about China. Into this book he incorporated his view of "the violent male type", which he described as a "man who had to be right", a man who "instantly attracts women" and who he said were the men who "run the world". Contemporary reviews were lukewarm at best, and van Vogt thereafter returned to science fiction. From 1963 through the mid-1980s, van Vogt once again published new material on a regular basis, though fix-ups and reworked material also appeared relatively often. His later novels included fix-ups such as "The Beast" (also known as "Moonbeast") (1963), "Rogue Ship" (1965), "Quest for the Future" (1970) and "Supermind" (1977). He also wrote novels by expanding previously published short stories; works of this type include "The Darkness on Diamondia" (1972) and "Future Glitter" (also known as "Tyranopolis"; 1973).
Novels that were written simply as novels, and not serialized magazine pieces or fix-ups, had been very rare in van Vogt's oeuvre, but began to appear regularly beginning in the 1970s. Van Vogt's original novels included "Children of Tomorrow" (1970), "The Battle of Forever" (1971) and "The Anarchistic Colossus" (1977). Over the years, many sequels to his classic works were promised, but only one appeared: "Null-A Three" (1984; originally published in French). Several later books were initially published in Europe, and at least one novel only ever appeared in foreign language editions and was never published in its original English. Final years. When the 1979 film "Alien" appeared, it was noted that the plot closely matched the plots of both "Black Destroyer" and "Discord in Scarlet", both published in "Astounding magazine" in 1939, and then later published in the 1950 book "Voyage of the Space Beagle". Van Vogt sued the production company for plagiarism, and eventually collected an out-of-court settlement of $50,000 from 20th Century Fox.
In increasingly frail health, van Vogt published his final short story in 1986. Personal life. Van Vogt's first wife, Edna Mayne Hull, died in 1975. Van Vogt married Lydia Bereginsky in 1979; they remained together until his death. Death. On January 26, 2000, A. E. van Vogt died in Los Angeles from Alzheimer's disease. He was survived by his second wife. Critical reception. Critical opinion about the quality of van Vogt's work is sharply divided. An early and articulate critic was Damon Knight. In a 1945 chapter-long essay reprinted in "In Search of Wonder," entitled "Cosmic Jerrybuilder: A. E. van Vogt", Knight described van Vogt as "no giant; he is a pygmy who has learned to operate an overgrown typewriter". Knight described "The World of Null-A" as "one of the worst allegedly adult science fiction stories ever published". Concerning van Vogt's writing, Knight said: About "Empire of the Atom" Knight wrote: Knight also expressed misgivings about van Vogt's politics. He noted that van Vogt's stories almost invariably present absolute monarchy in a favorable light. In 1974, Knight retracted some of his criticism after finding out about Vogt's writing down his dreams as a part of his working methods:
Knight's criticism greatly damaged van Vogt's reputation. On the other hand, when science fiction author Philip K. Dick was asked which science fiction writers had influenced his work the most, he replied: Dick also defended van Vogt against Damon Knight's criticisms: In a review of "Transfinite: The Essential A. E. van Vogt", science fiction writer Paul Di Filippo said: In "The John W. Campbell Letters", Campbell says, "The son-of-a-gun gets hold of you in the first paragraph, ties a knot around you, and keeps it tied in every paragraph thereafter—including the ultimate last one". Harlan Ellison (who had begun reading van Vogt as a teenager) wrote, "Van was the first writer to shine light on the restricted ways in which I had been taught to view the universe and the human condition". Writing in 1984, David Hartwell said: The literary critic Leslie A. Fiedler said something similar: American literary critic Fredric Jameson says of van Vogt: Van Vogt still has his critics. For example, Darrell Schweitzer, writing to "The New York Review of Science Fiction" in 1999, quoted a passage from the original van Vogt novelette "The Mixed Men", which he was then reading, and remarked:
Recognition. In 1946, van Vogt and his first wife, Edna Mayne Hull, were Guests of Honor at the fourth World Science Fiction Convention. In 1980, van Vogt received a "Casper Award" (precursor to the Canadian Prix Aurora Awards) for Lifetime Achievement. The Science Fiction Writers of America (SFWA) named him its 14th Grand Master in 1995 (presented 1996). Great controversy within SFWA accompanied its long wait in bestowing its highest honor (limited to living writers, no more than one annually). Writing an obituary of van Vogt, Robert J. Sawyer, a fellow Canadian writer of science fiction, remarked: It is generally held that a key factor in the delay was "damnable SFWA politics" reflecting the concerns of Damon Knight, the founder of the SFWA, who abhorred van Vogt's style and politics and thoroughly demolished his literary reputation in the 1950s. Harlan Ellison was more explicit in 1999 introduction to "Futures Past: The Best Short Fiction of A. E. van Vogt": In 1996, van Vogt received a Special Award from the World Science Fiction Convention "for six decades of golden age science fiction". That same year, the Science Fiction and Fantasy Hall of Fame inducted him in its inaugural class of two deceased and two living persons, along with writer Jack Williamson (also living) and editors Hugo Gernsback and John W. Campbell.
The works of van Vogt were translated into French by the surrealist Boris Vian ("The World of Null-A" as "Le Monde des Å" in 1958), and van Vogt's works were "viewed as great literature of the surrealist school". In addition, "Slan" was published in French, translated by Jean Rosenthal, under the title "À la poursuite des Slans", as part of the paperback series 'Editions J'ai Lu: Romans-Texte Integral' in 1973. This edition also listing the following works by van Vogt as having been published in French as part of this series: "Le Monde des Å", "La faune de l'espace", "Les joueurs du Å", "L'empire de l'atome", "Le sorcier de Linn", "Les armureries d'Isher", "Les fabricants d'armes", and "Le livre de Ptath". Van Vogt's last novel, 1985's "To Conquer Kiber", has only been released in French (as "À la conquête de Kiber".)
Anna Kournikova Anna Sergeyevna Kournikova Iglesias (née Kournikova; ; born 7 June 1981) is a Russian model and television personality, and former professional tennis player. Her appearance and celebrity status made her one of the best known tennis stars worldwide. At the peak of her fame, fans looking for images of Kournikova made her name one of the most common search strings on Google Search. Despite never winning a singles title, she reached No. 8 in the world in 2000. She achieved greater success playing doubles, where she was at times the world No. 1 player. With Martina Hingis as her partner, she won Grand Slam titles in Australia in 1999 and 2002, and the WTA Championships in 1999 and 2000. They referred to themselves as the "Spice Girls of Tennis". Kournikova retired from professional tennis in 2003 due to serious back and spinal problems, including a herniated disk. She lives in Miami Beach, Florida, and played in occasional exhibitions and in doubles for the St. Louis Aces of World TeamTennis before the team folded in 2011. She was a new trainer for season 12 of the television show "The Biggest Loser", replacing Jillian Michaels, but did not return for season 13. In addition to her tennis and television work, Kournikova serves as a Global Ambassador for Population Services International's "Five & Alive" program, which addresses health crises facing children under the age of five and their families.
Early life. Kournikova was born in Moscow, Russia, on 7 June 1981. Her father, Sergei Kournikov (born 1961), a former Greco-Roman wrestling champion, eventually earned a PhD and was a professor at the University of Physical Culture and Sport in Moscow. As of 2001, he was still a part-time martial arts instructor there. Her mother Alla (born 1963) had been a 400-metre runner. Her younger half-brother, Allan, is a youth golf world champion who was featured in the 2013 documentary film "The Short Game". Sergei Kournikov has said, "We were young and we liked the clean, physical life, so Anna was in a good environment for sport from the beginning". Kournikova received her first tennis racquet as a New Year gift in 1986 at the age of five. Describing her early regimen, she said, "I played two times a week from age six. It was a children's program. And it was just for fun; my parents didn't know I was going to play professionally, they just wanted me to do something because I had lots of energy. It was only when I started playing well at seven that I went to a professional academy. I would go to school, and then my parents would take me to the club, and I'd spend the rest of the day there just having fun with the kids." In 1986, Kournikova became a member of the Spartak Tennis Club, coached by Larissa Preobrazhenskaya. In 1989, at the age of eight, Kournikova began appearing in junior tournaments, and by the following year, was attracting attention from tennis scouts across the world. She signed a management deal at age ten and went to Bradenton, Florida, to train at Nick Bollettieri's celebrated tennis academy.
Tennis career. 1989–1997: early years and breakthrough. Following her arrival in the United States, she became prominent on the tennis scene. At the age of 14, she won the European Championships and the Italian Open Junior tournament. In December 1995, she became the youngest player to win the 18-and-under division of the Junior Orange Bowl tennis tournament. By the end of the year, Kournikova was crowned the ITF Junior World Champion U-18 and Junior European Champion U-18. Earlier, in September 1995, Kournikova, still only 14 years of age, debuted in the WTA Tour, when she received a wildcard into the qualifications at the WTA tournament in Moscow, the Moscow Ladies Open, and qualified before losing in the second round of the main draw to third-seeded Sabine Appelmans. She also reached her first WTA Tour doubles final in that debut appearance – partnering with 1995 Wimbledon girls' champion in both singles and doubles Aleksandra Olsza, she lost the title match to Meredith McGrath and Larisa Savchenko-Neiland.
In February–March 1996, Kournikova won two ITF titles, in Midland, Michigan and Rockford, Illinois. Still only 14 years of age, in April 1996 she debuted at the Fed Cup for Russia, the youngest player ever to participate and win a match. In 1996, she started playing under a new coach, Ed Nagel. Her six-year association with Nagel was successful. At 15, she made her Grand Slam debut, reaching the fourth round of the 1996 US Open, losing to Steffi Graf, the eventual champion. After this tournament, Kournikova's ranking jumped from No. 144 to debut in the Top 100 at No. 69. Kournikova was a member of the Russian delegation to the 1996 Olympic Games in Atlanta, Georgia. In 1996, she was named WTA Newcomer of the Year, and she was ranked No. 57 in the end of the season. Kournikova entered the 1997 Australian Open as world No. 67, where she lost in the first round to world No. 12, Amanda Coetzer. At the Italian Open, Kournikova lost to Amanda Coetzer in the second round. She reached the semi-finals in the doubles partnering with Elena Likhovtseva, before losing to the sixth seeds Mary Joe Fernández and Patricia Tarabini.
At the French Open, Kournikova made it to the third round before losing to world No. 1, Martina Hingis. She also reached the third round in doubles with Likhovtseva. At the Wimbledon Championships, Kournikova became only the second woman in the open era to reach the semi-finals in her Wimbledon debut, the first being Chris Evert in 1972. There she lost to eventual champion Martina Hingis. At the US Open, she lost in the second round to the eleventh seed Irina Spîrlea. Partnering with Likhovtseva, she reached the third round of the women's doubles event. Kournikova played her last WTA Tour event of 1997 at Porsche Tennis Grand Prix in Filderstadt, losing to Amanda Coetzer in the second round of singles, and in the first round of doubles to Lindsay Davenport and Jana Novotná partnering with Likhovtseva. She broke into the top 50 on 19 May, and was ranked No. 32 in singles and No. 41 in doubles at the end of the season. 1998–2000: success and stardom. In 1998, Kournikova broke into the WTA's top 20 rankings for the first time, when she was ranked No. 16. At the Australian Open, Kournikova lost in the third round to world No. 1 player, Martina Hingis. She also partnered with Larisa Savchenko-Neiland in women's doubles, and they lost to eventual champions Hingis and Mirjana Lučić in the second round. Although she lost in the second round of the Paris Open to Anke Huber in singles, Kournikova reached her second doubles WTA Tour final, partnering with Larisa Savchenko-Neiland. They lost to Sabine Appelmans and Miriam Oremans. Kournikova and Savchenko-Neiland reached their second consecutive final at the Linz Open, losing to Alexandra Fusai and Nathalie Tauziat. At the Miami Open, Kournikova reached her first WTA Tour singles final, before losing to Venus Williams in the final.
Kournikova then reached two consecutive quarterfinals, at Amelia Island and the Italian Open, losing respectively to Lindsay Davenport and Martina Hingis. At the German Open, she reached the semi-finals in both singles and doubles, partnering with Larisa Savchenko-Neiland. At the French Open Kournikova had her best result at this tournament, making it to the fourth round before losing to Jana Novotná. She also reached her first Grand Slam doubles semi-finals, losing with Savchenko-Neiland to Lindsay Davenport and Natasha Zvereva. During her quarterfinals match at the grass-court Eastbourne Open versus Steffi Graf, Kournikova injured her thumb, which would eventually force her to withdraw from the 1998 Wimbledon Championships. However, she won that match, but then withdrew from her semi-finals match against Arantxa Sánchez Vicario. Kournikova returned for the Du Maurier Open and made it to the third round, before losing to Conchita Martínez. At the US Open Kournikova reached the fourth round before losing to Arantxa Sánchez Vicario. Her strong year qualified her for the year-end 1998 WTA Tour Championships, but she lost to Monica Seles in the first round. However, with Seles, she won her first WTA doubles title, in Tokyo, beating Mary Joe Fernández and Arantxa Sánchez Vicario in the final. At the end of the season, she was ranked No. 10 in doubles.
At the start of the 1999 season, Kournikova advanced to the fourth round in singles at the Australian Open before losing to Mary Pierce. In the doubles Kournikova won her first Grand Slam title, partnering with Martina Hingis to defeat Lindsay Davenport and Natasha Zvereva in the final. At the Tier I Family Circle Cup, Kournikova reached her second WTA Tour final, but lost to Martina Hingis. She then defeated Jennifer Capriati, Lindsay Davenport and Patty Schnyder on her route to the Bausch & Lomb Championships semi-finals, losing to Ruxandra Dragomir. At The French Open, Kournikova reached the fourth round before losing to eventual champion Steffi Graf. Once the grass-court season commenced in England, Kournikova lost to Nathalie Tauziat in the semi-finals in Eastbourne. At Wimbledon, Kournikova lost to Venus Williams in the fourth round. She also reached the final in mixed doubles, partnering with Jonas Björkman, but they lost to Leander Paes and Lisa Raymond. Kournikova again qualified for year-end WTA Tour Championships, but lost to Mary Pierce in the first round, and ended the season as World No. 12.
While Kournikova had a successful singles season, she was even more successful in doubles. After their victory at the Australian Open, she and Martina Hingis won tournaments in Indian Wells, Rome, Eastbourne and the WTA Tour Championships, and reached the final of The French Open where they lost to Serena and Venus Williams. Partnering with Elena Likhovtseva, Kournikova also reached the final in Stanford. On 22 November 1999 she reached the world No. 1 ranking in doubles, and ended the season at this ranking. Kournikova and Hingis were presented with the WTA Award for Doubles Team of the Year. Kournikova opened her 2000 season winning the Gold Coast Open doubles tournament partnering with Julie Halard. She then reached the singles semi-finals at the Medibank International Sydney, losing to Lindsay Davenport. At the Australian Open, she reached the fourth round in singles and the semi-finals in doubles. That season, Kournikova reached eight semi-finals (Sydney, Scottsdale, Stanford, San Diego, Luxembourg, Leipzig and Tour Championships), seven quarterfinals (Gold Coast, Tokyo, Amelia Island, Hamburg, Eastbourne, Zürich and Philadelphia) and one final. On 20 November 2000 she broke into top 10 for the first time, reaching No. 8. She was also ranked No. 4 in doubles at the end of the season. Kournikova was once again, more successful in doubles. She reached the final of the US Open in mixed doubles, partnering with Max Mirnyi, but they lost to Jared Palmer and Arantxa Sánchez Vicario. She also won six doubles titles – Gold Coast (with Julie Halard), Hamburg (with Natasha Zvereva), Filderstadt, Zürich, Philadelphia and the Tour Championships (with Martina Hingis). 2001–2003: injuries and final years.
Her 2001 season was plagued by injuries, including a left foot stress fracture which made her withdraw from 12 tournaments, including the French Open and Wimbledon. She underwent surgery in April. She reached her second career grand slam quarterfinals, at the Australian Open. Kournikova then withdrew from several events due to continuing problems with her left foot and did not return until Leipzig. With Barbara Schett, she won the doubles title in Sydney. She then lost in the finals in Tokyo, partnering with Iroda Tulyaganova, and at San Diego, partnering with Martina Hingis. Hingis and Kournikova also won the Kremlin Cup. At the end of the 2001 season, she was ranked No. 74 in singles and No. 26 in doubles. Kournikova regained some success in 2002. She reached the semi-finals of Auckland, Tokyo, Acapulco and San Diego, and the final of the China Open, losing to Anna Smashnova. This was Kournikova's last singles final. With Martina Hingis, she lost in the final at Sydney, but they won their second Grand Slam title together, the Australian Open. They also lost in the quarterfinals of the US Open. With Chanda Rubin, Kournikova played the semi-finals of Wimbledon, but they lost to Serena and Venus Williams. Partnering with Janet Lee, she won the Shanghai title. At the end of 2002 season, she was ranked No. 35 in singles and No. 11 in doubles.
In 2003, Anna Kournikova achieved her first Grand Slam match victory in two years at the Australian Open. She defeated Henrieta Nagyová in the first round, and then lost to Justine Henin-Hardenne in the 2nd round. She withdrew from Tokyo due to a sprained back suffered at the Australian Open and did not return to Tour until Miami. On 9 April, in what would be the final WTA match of her career, Kournikova dropped out in the first round of the Family Circle Cup in Charleston, due to a left adductor strain. Her singles world ranking was 67. She reached the semi-finals at the ITF tournament in Sea Island, before withdrawing from a match versus Maria Sharapova due to the adductor injury. She lost in the first round of the ITF tournament in Charlottesville. She did not compete for the rest of the season due to a continuing back injury. At the end of the 2003 season and her professional career, she was ranked No. 305 in singles and No. 176 in doubles. Kournikova's two Grand Slam doubles titles came in 1999 and 2002, both at the Australian Open in the Women's Doubles event with partner Martina Hingis. Kournikova proved a successful doubles player on the professional circuit, winning 16 tournament doubles titles, including two Australian Opens and being a finalist in mixed doubles at the US Open and at Wimbledon, and reaching the No. 1 ranking in doubles in the WTA Tour rankings. Her pro career doubles record was 200–71. However, her singles career plateaued after 1999. For the most part, she managed to retain her ranking between 10 and 15 (her career high singles ranking was No.8), but her expected finals breakthrough failed to occur; she only reached four finals out of 130 singles tournaments, never in a Grand Slam event, and never won one.
Her singles record is 209–129. Her final playing years were marred by a string of injuries, especially back injuries, which caused her ranking to erode gradually. As a personality Kournikova was among the most common search strings for both articles and images in her prime. 2004–present: exhibitions and World Team Tennis. Kournikova has not played on the WTA Tour since 2003, but still plays exhibition matches for charitable causes. In late 2004, she participated in three events organized by Elton John and by fellow tennis players Serena Williams and Andy Roddick. In January 2005, she played in a doubles charity event for the Indian Ocean tsunami with John McEnroe, Andy Roddick, and Chris Evert. In November 2005, she teamed up with Martina Hingis, playing against Lisa Raymond and Samantha Stosur in the WTT finals for charity. Kournikova is also a member of the St. Louis Aces in the World Team Tennis (WTT), playing doubles only. In September 2008, Kournikova showed up for the 2008 Nautica Malibu Triathlon held at Zuma Beach in Malibu, California. The Race raised funds for children's Hospital Los Angeles. She won that race for women's K-Swiss team. On 27 September 2008, Kournikova played exhibition mixed doubles matches in Charlotte, North Carolina, partnering with Tim Wilkison and Karel Nováček. Kournikova and Wilkison defeated Jimmy Arias and Chanda Rubin, and then Kournikova and Novacek defeated Rubin and Wilkison.
On 12 October 2008, Anna Kournikova played one exhibition match for the annual charity event, hosted by Billie Jean King and Elton John, and raised more than $400,000 for the Elton John AIDS Foundation and Atlanta AIDS Partnership Fund. She played doubles with Andy Roddick (they were coached by David Chang) versus Martina Navratilova and Jesse Levine (coached by Billie Jean King); Kournikova and Roddick won. Kournikova was one of "four former world No. 1 players" who participated in "Legendary Night", held on 2 May 2009, at the Turning Stone Event Center in Verona, New York, the others being John McEnroe (who had been No. 1 in both singles and doubles), Tracy Austin and Jim Courier (both of whom who had been No. 1 in singles but not doubles). The exhibition included a mixed doubles match in which McEnroe and Kournikova defeated Courier and Austin. In 2008, she was named a spokesperson for K-Swiss. In 2005, Kournikova stated that if she were 100% fit, she would like to come back and compete again. In June 2010, Kournikova reunited with her doubles partner Martina Hingis to participate in competitive tennis for the first time in seven years in the Invitational Ladies Doubles event at Wimbledon. On 29 June 2010 they defeated the British pair Samantha Smith and Anne Hobbs.
Playing style. Kournikova plays right-handed with a two-handed backhand. She is a great player at the net. She can hit forceful groundstrokes and also drop shots. Her playing style fits the profile for a doubles player, and is complemented by her height. She has been compared to such doubles specialists as Pam Shriver and Peter Fleming. Personal life. Kournikova was in a relationship with fellow Russian, Pavel Bure, an NHL ice hockey player. The two met in 1999, when Kournikova was still linked to Bure's former Russian teammate Sergei Fedorov. Bure and Kournikova were reported to have been engaged in 2000 after a reporter took a photo of them together in a Florida restaurant where Bure supposedly asked Kournikova to marry him. As the story made headlines in Russia, where they were both heavily followed in the media as celebrities, Bure and Kournikova both denied any engagement. Kournikova, 10 years younger than Bure, was 18 years old at the time. Fedorov claimed that he and Kournikova were married in 2001, and divorced in 2003. Kournikova's representatives deny any marriage to Fedorov; however, Fedorov's agent Pat Brisson claims that although he does not know when they got married, he knew "Fedorov was married".
Kournikova started dating singer Enrique Iglesias in late 2001 after she had appeared in his music video for "Escape". The couple have three children together, fraternal twins, a son and daughter, born on 16 December 2017, and another daughter born on 30 January 2020. It was reported in 2010 that Kournikova had become an American citizen. Media publicity. In 2000, Kournikova became the new face for Berlei's shock absorber sports bras, and appeared in the "only the ball should bounce" billboard campaign. Following that, she was cast by the Farrelly brothers for a minor role in the 2000 film "Me, Myself & Irene" starring Jim Carrey and Renée Zellweger. Photographs of her have appeared on covers of various publications, including men's magazines, such as one in the much-publicized 2004 "Sports Illustrated Swimsuit Issue", where she posed in bikinis and swimsuits, as well as in "FHM" and "Maxim". Kournikova was named one of "People"s 50 Most Beautiful People in 1998 and was voted "hottest female athlete" on ESPN.com. In 2002, she also placed first in "FHM's 100 Sexiest Women in the World" in US and UK editions. By contrast, ESPN – citing the degree of hype as compared to actual accomplishments as a singles player – ranked Kournikova 18th in its "25 Biggest Sports Flops of the Past 25 Years". Kournikova was also ranked No. 1 in the ESPN Classic series "Who's number 1?" when the series featured sport's most overrated athletes.
She continued to be the most searched athlete on the Internet through 2008 even though she had retired from the professional tennis circuit years earlier. After slipping from first to sixth among athletes in 2009, she moved back up to third place among athletes in terms of search popularity in 2010. In October 2010, Kournikova headed to NBC's "The Biggest Loser" where she led the contestants in a tennis-workout challenge. In May 2011, it was announced that Kournikova would join "The Biggest Loser" as a regular celebrity trainer in season 12. She did not return for season 13. External links.
Alfons Maria Jakob Alfons Maria Jakob (2 July 1884 – 17 October 1931) was a German neurologist who worked in the field of neuropathology. He was born in Aschaffenburg, Bavaria and educated in medicine at the universities of Munich, Berlin, and Strasbourg, where he received his doctorate in 1908. During the following year, he began clinical work under the psychiatrist Emil Kraepelin and did laboratory work with Franz Nissl and Alois Alzheimer in Munich. In 1911, by way of an invitation from Wilhelm Weygandt, he relocated to Hamburg, where he worked with Theodor Kaes and eventually became head of the laboratory of anatomical pathology at the psychiatric State Hospital Hamburg-Friedrichsberg. Following the death of Kaes in 1913, Jakob succeeded him as prosector. During World War I he served as an army physician in Belgium, and afterwards returned to Hamburg. In 1919, he obtained his habilitation for neurology and in 1924 became a professor of neurology. Under Jakob's guidance the department grew rapidly. He made significant contributions to knowledge on concussion and secondary nerve degeneration and became a doyen of neuropathology.
Jakob was the author of five monographs and nearly 80 scientific papers. His neuropathological research contributed greatly to the delineation of several diseases, including multiple sclerosis and Friedreich's ataxia. He first recognised and described Alper's disease and Creutzfeldt–Jakob disease (named along with Munich neuropathologist Hans Gerhard Creutzfeldt). He gained experience in neurosyphilis, having a 200-bed ward devoted entirely to that disorder. Jakob made a lecture tour of the United States (1924) and South America (1928), of which, he wrote a paper on the neuropathology of yellow fever. He suffered from chronic osteomyelitis for the last seven years of his life. This eventually caused a retroperitoneal abscess and paralytic ileus from which he died following operation.
Agnosticism Agnosticism is the view or belief that the existence of God, the divine, or the supernatural is either unknowable in principle or unknown in fact. It can also mean an apathy towards such religious belief and refer to personal limitations rather than a worldview. Another definition is the view that "human reason is incapable of providing sufficient rational grounds to justify either the belief that God exists or the belief that God does not exist." The English biologist Thomas Henry Huxley said that he originally coined the word "agnostic" in 1869 "to denote people who, like [himself], confess themselves to be hopelessly ignorant concerning a variety of matters [including the matter of God's existence], about which metaphysicians and theologians, both orthodox and heterodox, dogmatise with the utmost confidence." Earlier thinkers had written works that promoted agnostic points of view, such as Sanjaya Belatthiputta, a 5th-century BCE Indian philosopher who expressed agnosticism about any afterlife; and Protagoras, a 5th-century BCE Greek philosopher who expressed agnosticism about the existence of "the gods".
Defining agnosticism. Being a scientist, above all else, Huxley presented agnosticism as a form of demarcation. A hypothesis with no supporting, objective, testable evidence is not an objective, scientific claim. As such, there would be no way to test said hypotheses, leaving the results inconclusive. His agnosticism was not compatible with forming a belief as to the truth, or falsehood, of the claim at hand. Karl Popper would also describe himself as an agnostic. According to philosopher William L. Rowe, in this strict sense, agnosticism is the view that human reason is incapable of providing sufficient rational grounds to justify either the belief that God exists or the belief that God does not exist. George H. Smith, while admitting that the narrow definition of atheist was the common usage definition of that word, and admitting that the broad definition of agnostic was the common usage definition of that word, promoted broadening the definition of atheist and narrowing the definition of agnostic. Smith rejects agnosticism as a third alternative to theism and atheism and promotes terms such as agnostic atheism (the view of those who do not hold a belief in the existence of any deity but claim that the existence of a deity is unknown or inherently unknowable) and agnostic theism (the view of those who believe in the existence of a deity(s) but claim that the existence of a deity is unknown or inherently unknowable).
Etymology. "Agnostic" () was used by Thomas Henry Huxley in a speech at a meeting of the Metaphysical Society in 1869 to describe his philosophy, which rejects all claims of spiritual or mystical knowledge. Early Christian church leaders used the Greek word "gnosis" (knowledge) to describe "spiritual knowledge". Agnosticism is not to be confused with religious views opposing the ancient religious movement of Gnosticism in particular; Huxley used the term in a broader, more abstract sense. Huxley identified agnosticism not as a creed but rather as a method of skeptical, evidence-based inquiry. The term "agnostic" is also cognate with the Sanskrit word "ajñasi", which translates literally to "not knowable", and relates to the ancient Indian philosophical school of Ajñana, which proposes that it is impossible to obtain knowledge of metaphysical nature or ascertain the truth value of philosophical propositions; and even if knowledge were possible, it is useless and disadvantageous for final salvation. In recent years, scientific literature dealing with neuroscience and psychology has used the word to mean "not knowable". In technical and marketing literature, "agnostic" can also mean independence from some parameters—for example, "platform agnostic" (referring to cross-platform software), or "hardware-agnostic".
Qualifying agnosticism. Scottish Enlightenment philosopher David Hume contended that meaningful statements about the universe are always qualified by some degree of doubt. He asserted that the fallibility of human beings means that they cannot obtain absolute certainty except in trivial cases where a statement is true by definition (e.g. tautologies such as "all bachelors are unmarried" or "all triangles have three corners"). Types. Strong agnosticism. Also called "hard", "closed", "strict", or "permanent agnosticism", strong agnosticism is the view that the question of the existence or nonexistence of a deity or deities, and the nature of ultimate reality is unknowable by reason of our natural inability to verify any subjective experience with anything but another subjective experience. A strong agnostic would say, "I cannot know whether a deity exists or not, and neither can you." Weak agnosticism. Also called "soft", "open", "empirical", "hopeful", or "temporal agnosticism", weak agnosticism is the view that the existence or nonexistence of any deities is currently unknown but is not necessarily unknowable; therefore, one will withhold judgement until evidence, if any, becomes available. A weak agnostic would say, "I don't know whether any deities exist or not, but maybe one day, if there is evidence, we can find something out."
Apathetic agnosticism. The view that no amount of debate can prove or disprove the existence of one or more deities, and if one or more deities exist, they do not appear to be concerned about the fate of humans. Therefore, their existence has little to no impact on personal human affairs and should be of little interest. An apathetic agnostic would say, "I don't know whether any deity exists or not, and I don't care if any deity exists or not." History. Hindu philosophy. Throughout the history of Hinduism there has been a strong tradition of philosophic speculation and skepticism. The Rig Veda takes an agnostic view on the fundamental question of how the universe and the gods were created. Nasadiya Sukta ("Creation Hymn") in the tenth chapter of the Rig Veda says: Hume, Kant, and Kierkegaard. Aristotle, Anselm, Aquinas, Descartes, and Gödel presented arguments attempting to rationally prove the existence of God. The skeptical empiricism of David Hume, the antinomies of Immanuel Kant, and the existential philosophy of Søren Kierkegaard convinced many later philosophers to abandon these attempts, regarding it impossible to construct any unassailable proof for the existence or non-existence of God.
In his 1844 book "Philosophical Fragments", Kierkegaard writes: Hume was Huxley's favourite philosopher, calling him "the Prince of Agnostics". Diderot wrote to his mistress, telling of a visit by Hume to the Baron D'Holbach, and describing how a word for the position that Huxley would later describe as agnosticism did not seem to exist, or at least was not common knowledge, at the time. United Kingdom. Charles Darwin. Raised in a religious environment, Charles Darwin (1809–1882) studied to be an Anglican clergyman. While eventually doubting parts of his faith, Darwin continued to help in church affairs, even while avoiding church attendance. Darwin stated that it would be "absurd to doubt that a man might be an ardent theist and an evolutionist". Although reticent about his religious views, in 1879 he wrote that "I have never been an atheist in the sense of denying the existence of a God. – I think that generally ... an agnostic would be the most correct description of my state of mind." Thomas Henry Huxley.
Agnostic views are as old as philosophical skepticism, but the terms agnostic and agnosticism were created by Huxley (1825–1895) to sum up his thoughts on contemporary developments of metaphysics about the "unconditioned" (William Hamilton) and the "unknowable" (Herbert Spencer). Though Huxley began to use the term "agnostic" in 1869, his opinions had taken shape some time before that date. In a letter of September 23, 1860, to Charles Kingsley, Huxley discussed his views extensively: And again, to the same correspondent, May 6, 1863: Of the origin of the name agnostic to describe this attitude, Huxley gave the following account: William Stewart Ross. William Stewart Ross (1844–1906) wrote under the name of Saladin. He was associated with Victorian Freethinkers and the organization the British Secular Union. He edited the "Secular Review" from 1882; it was renamed "Agnostic Journal and Eclectic Review" and closed in 1907. Ross championed agnosticism in opposition to the atheism of Charles Bradlaugh as an open-ended spiritual exploration.
In "Why I am an Agnostic" () he claims that agnosticism is "the very reverse of atheism". Bertrand Russell. Bertrand Russell (1872–1970) declared "Why I Am Not a Christian" in 1927, a classic statement of agnosticism. He calls upon his readers to "stand on their own two feet and look fair and square at the world with a fearless attitude and a free intelligence". In 1939, Russell gave a lecture on "The existence and nature of God", in which he characterized himself as an atheist. He said: However, later in the same lecture, discussing modern non-anthropomorphic concepts of God, Russell states: In Russell's 1947 pamphlet, "Am I An Atheist or an Agnostic?" (subtitled "A Plea For Tolerance in the Face of New Dogmas"), he ruminates on the problem of what to call himself: In his 1953 essay, "What Is An Agnostic?" Russell states: Later in the essay, Russell adds: Leslie Weatherhead. In 1965, Christian theologian Leslie Weatherhead (1893–1976) published "The Christian Agnostic", in which he argues: Although radical and unpalatable to conventional theologians, Weatherhead's "agnosticism" falls far short of Huxley's, and short even of "weak agnosticism":
United States. Robert G. Ingersoll. Robert G. Ingersoll (1833–1899), an Illinois lawyer and politician who evolved into a well-known and sought-after orator in 19th-century America, has been referred to as the "Great Agnostic". In an 1896 lecture titled "Why I Am An Agnostic", Ingersoll stated this: In the conclusion of the speech he simply sums up the agnostic position as: In 1885, Ingersoll explained his comparative view of agnosticism and atheism as follows: Bernard Iddings Bell. Canon Bernard Iddings Bell (1886–1958), a popular cultural commentator, Episcopal priest, and author, lauded the necessity of agnosticism in "Beyond Agnosticism: A Book for Tired Mechanists", calling it the foundation of "all intelligent Christianity". Agnosticism was a temporary mindset in which one rigorously questioned the truths of the age, including the way in which one believed God. His view of Robert Ingersoll and Thomas Paine was that they were not denouncing true Christianity but rather "a gross perversion of it". Part of the misunderstanding stemmed from ignorance of the concepts of God and religion. Historically, a god was any real, perceivable force that ruled the lives of humans and inspired admiration, love, fear, and homage; religion was the practice of it. Ancient peoples worshiped gods with real counterparts, such as Mammon (money and material things), Nabu (rationality), or Ba'al (violent weather); Bell argued that modern peoples were still paying homage—with their lives and their children's lives—to these old gods of wealth, physical appetites, and self-deification. Thus, if one attempted to be agnostic passively, he or she would incidentally join the worship of the world's gods.
In "Unfashionable Convictions" (1931), he criticized the Enlightenment's complete faith in human sensory perception, augmented by scientific instruments, as a means of accurately grasping Reality. Firstly, it was fairly new, an innovation of the Western World, which Aristotle invented and Thomas Aquinas revived among the scientific community. Secondly, the divorce of "pure" science from human experience, as manifested in American Industrialization, had completely altered the environment, often disfiguring it, so as to suggest its insufficiency to human needs. Thirdly, because scientists were constantly producing more data—to the point where no single human could grasp it all at once—it followed that human intelligence was incapable of attaining a complete understanding of universe; therefore, to admit the mysteries of the unobserved universe was to be "actually" scientific. Bell believed that there were two other ways that humans could perceive and interact with the world. "Artistic experience" was how one expressed meaning through speaking, writing, painting, gesturing—any sort of communication which shared insight into a human's inner reality. "Mystical experience" was how one could "read" people and harmonize with them, being what we commonly call love. In summary, man was a scientist, artist, and lover. Without exercising all three, a person became "lopsided".
Bell considered a humanist to be a person who cannot rightly ignore the other ways of knowing. However, humanism, like agnosticism, was also temporal, and would eventually lead to either scientific materialism or theism. He lays out the following thesis: Demographics. Demographic research services normally do not differentiate between various types of non-religious respondents, so agnostics are often classified in the same category as atheists or other non-religious people. A 2010 survey published in "Encyclopædia Britannica" found that the non-religious people or the agnostics made up about 9.6% of the world's population. A November–December 2006 poll published in the "Financial Times" gives rates for the United States and five European countries. The rates of agnosticism in the United States were at 14%, while the rates of agnosticism in the European countries surveyed were considerably higher: Italy (20%), Spain (30%), Great Britain (35%), Germany (25%), and France (32%). A study conducted by the Pew Research Center found that about 16% of the world's people, the third largest group after Christianity and Islam, have no religious affiliation.
According to a 2012 report by the Pew Research Center, agnostics made up 3.3% of the US adult population. In the "U.S. Religious Landscape Survey", conducted by the Pew Research Center, 55% of agnostic respondents expressed "a belief in God or a universal spirit", whereas 41% stated that they thought that they felt a tension "being non-religious in a society where most people are religious". According to the 2021 Australian Bureau of Statistics, 38.9% of Australians have "no religion", a category that includes agnostics. Between 64% and 65% of Japanese, and up to 81% of Vietnamese, are atheists, agnostics, or do not believe in a god. An official European Union survey reported that 3% of the EU population is unsure about their belief in a god or spirit. Criticism. Agnosticism is criticized from a variety of standpoints. Some atheists criticize the use of the term agnosticism as functionally indistinguishable from atheism; this results in frequent criticisms of those who adopt the term as avoiding the atheist label.
Theistic. Theistic critics claim that agnosticism is impossible in practice, since a person can live only either as if God did not exist ("etsi deus non-daretur"), or as if God did exist ("etsi deus daretur"). Christian. According to Pope Benedict XVI, strong agnosticism in particular contradicts itself in affirming the power of reason to know scientific truth. He blames the exclusion of reasoning from religion and ethics for dangerous pathologies such as crimes against humanity and ecological disasters. "Agnosticism", said Benedict, "is always the fruit of a refusal of that knowledge which is in fact offered to man ... The knowledge of God has always existed". He asserted that agnosticism is a choice of comfort, pride, dominion, and utility over truth, and is opposed by the following attitudes: the keenest self-criticism, humble listening to the whole of existence, the persistent patience and self-correction of the scientific method, a readiness to be purified by the truth. The Catholic Church sees merit in examining what it calls "partial agnosticism", specifically those systems that "do not aim at constructing a complete philosophy of the unknowable, but at excluding special kinds of truth, notably religious, from the domain of knowledge". However, the Church is historically opposed to a full denial of the capacity of human reason to know God. The Council of the Vatican declares, "God, the beginning and end of all, can, by the natural light of human reason, be known with certainty from the works of creation".
Blaise Pascal argued that even if there were truly no evidence for God, agnostics should consider what is now known as Pascal's Wager: the infinite expected value of acknowledging God is always greater than the finite expected value of not acknowledging his existence, and thus it is a safer "bet" to choose God. Atheistic. According to Richard Dawkins, a distinction between agnosticism and atheism is unwieldy and depends on how close to zero a person is willing to rate the probability of existence for any given god-like entity. About himself, Dawkins continues, "I am agnostic only to the extent that I am agnostic about fairies at the bottom of the garden." Dawkins also identifies two categories of agnostics; "Temporary Agnostics in Practice" (TAPs), and "Permanent Agnostics in Principle" (PAPs). He states that "agnosticism about the existence of God belongs firmly in the temporary or TAP category. Either he exists or he doesn't. It is a scientific question; one day we may know the answer, and meanwhile we can say something pretty strong about the probability", and considers PAP a "deeply inescapable kind of fence-sitting".
Ignosticism. A related concept is ignosticism, the view that a coherent definition of a deity must be put forward before the question of the existence of a deity can be meaningfully discussed. If the chosen definition is not coherent, the ignostic holds the noncognitivist view that the existence of a deity is meaningless or empirically untestable. A. J. Ayer, Theodore Drange, and other philosophers see both atheism and agnosticism as incompatible with ignosticism on the grounds that atheism and agnosticism accept the statement "a deity exists" as a meaningful proposition that can be argued for or against.
Argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust. Nearly all argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in supernovas. The name "argon" is derived from the Greek word , neuter singular form of meaning 'lazy' or 'inactive', as a reference to the fact that the element undergoes almost no chemical reactions. The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements. Its triple point temperature of 83.8058 K is a defining fixed point in the International Temperature Scale of 1990.
Argon is extracted industrially by the fractional distillation of liquid air. It is mostly used as an inert shielding gas in welding and other high-temperature industrial processes where ordinarily unreactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. It is also used in incandescent and fluorescent lighting, and other gas-discharge tubes. It makes a distinctive blue-green gas laser. It is also used in fluorescent glow starters. Characteristics. Argon has approximately the same solubility in water as oxygen and is 2.5 times more soluble in water than nitrogen. Argon is colorless, odorless, nonflammable and nontoxic as a solid, liquid or gas. Argon is chemically inert under most conditions and forms no confirmed stable compounds at room temperature. Although argon is a noble gas, it can form some compounds under various extreme conditions. Argon fluorohydride (HArF), a compound of argon with fluorine and hydrogen that is stable below , has been demonstrated. Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form clathrates with water when atoms of argon are trapped in a lattice of water molecules. Ions, such as , and excited-state complexes, such as ArF, have been demonstrated. Theoretical calculation predicts several more argon compounds that should be stable but have not yet been synthesized.
History. "Argon" (Greek , neuter singular form of meaning "lazy" or "inactive") is named in reference to its chemical inactivity. This chemical property of this first noble gas to be discovered impressed the namers. An unreactive gas was suspected to be a component of air by Henry Cavendish in 1785. Argon was first isolated from air in 1894 by Lord Rayleigh and Sir William Ramsay at University College London by removing oxygen, carbon dioxide, water, and nitrogen from a sample of clean air. They first accomplished this by replicating an experiment of Henry Cavendish's. They trapped a mixture of atmospheric air with additional oxygen in a test-tube (A) upside-down over a large quantity of dilute alkali solution (B), which in Cavendish's original experiment was potassium hydroxide, and conveyed a current through wires insulated by U-shaped glass tubes (CC) which sealed around the platinum wire electrodes, leaving the ends of the wires (DD) exposed to the gas and insulated from the alkali solution. The arc was powered by a battery of five Grove cells and a Ruhmkorff coil of medium size. The alkali absorbed the oxides of nitrogen produced by the arc and also carbon dioxide. They operated the arc until no more reduction of volume of the gas could be seen for at least an hour or two and the spectral lines of nitrogen disappeared when the gas was examined. The remaining oxygen was reacted with alkaline pyrogallate to leave behind an apparently non-reactive gas which they called argon.
Before isolating the gas, they had determined that nitrogen produced from chemical compounds was 0.5% lighter than nitrogen from the atmosphere. The difference was slight, but it was important enough to attract their attention for many months. They concluded that there was another gas in the air mixed in with the nitrogen. Argon was also encountered in 1882 through independent research of H. F. Newall and W. N. Hartley. Each observed new lines in the emission spectrum of air that did not match known elements. Prior to 1957, the symbol for argon was "A". This was changed to Ar after the International Union of Pure and Applied Chemistry published the work "Nomenclature of Inorganic Chemistry" in 1957. Occurrence. Argon constitutes 0.934% by volume and 1.288% by mass of Earth's atmosphere. Air is the primary industrial source of purified argon products. Argon is isolated from air by fractionation, most commonly by cryogenic fractional distillation, a process that also produces purified nitrogen, oxygen, neon, krypton and xenon. Earth's crust and seawater contain 1.2 ppm and 0.45 ppm of argon, respectively.
Isotopes. The main isotopes of argon found on Earth are (99.6%), (0.34%), and (0.06%). Naturally occurring , with a half-life of 1.25 years, decays to stable (11.2%) by electron capture or positron emission, and also to stable (88.8%) by beta decay. These properties and ratios are used to determine the age of rocks by K–Ar dating. In Earth's atmosphere, is made by cosmic ray activity, primarily by neutron capture of followed by two-neutron emission. In the subsurface environment, it is also produced through neutron capture by , followed by proton emission. is created from the neutron capture by followed by an alpha particle emission as a result of subsurface nuclear explosions. It has a half-life of 35 days. Between locations in the Solar System, the isotopic composition of argon varies greatly. Where the major source of argon is the decay of in rocks, will be the dominant isotope, as it is on Earth. Argon produced directly by stellar nucleosynthesis is dominated by the alpha-process nuclide . Correspondingly, solar argon contains 84.6% (according to solar wind measurements), and the ratio of the three isotopes 36Ar : 38Ar : 40Ar in the atmospheres of the outer planets is 8400 : 1600 : 1. This contrasts with the low abundance of primordial in Earth's atmosphere, which is only 31.5 ppmv (= 9340 ppmv × 0.337%), comparable with that of neon (18.18 ppmv) on Earth and with interplanetary gasses, measured by probes.
The atmospheres of Mars, Mercury and Titan (the largest moon of Saturn) contain argon, predominantly as . The predominance of radiogenic is the reason the standard atomic weight of terrestrial argon is greater than that of the next element, potassium, a fact that was puzzling when argon was discovered. Mendeleev positioned the elements on his periodic table in order of atomic weight, but the inertness of argon suggested a placement "before" the reactive alkali metal. Henry Moseley later solved this problem by showing that the periodic table is actually arranged in order of atomic number (see History of the periodic table). Compounds. Argon's complete octet of electrons indicates full s and p subshells. This full valence shell makes argon very stable and extremely resistant to bonding with other elements. Before 1962, argon and the other noble gases were considered to be chemically inert and unable to form compounds; however, compounds of the heavier noble gases have since been synthesized. The first argon compound with tungsten pentacarbonyl, W(CO)5Ar, was isolated in 1975. However, it was not widely recognised at that time. In August 2000, another argon compound, argon fluorohydride (HArF), was formed by researchers at the University of Helsinki, by shining ultraviolet light onto frozen argon containing a small amount of hydrogen fluoride with caesium iodide. This discovery caused the recognition that argon could form weakly bound compounds, even though it was not the first. It is stable up to 17 kelvins (−256 °C). The metastable dication, which is valence-isoelectronic with carbonyl fluoride and phosgene, was observed in 2010. Argon-36, in the form of argon hydride (argonium) ions, has been detected in interstellar medium associated with the Crab Nebula supernova; this was the first noble-gas molecule detected in outer space.
Solid argon hydride (Ar(H2)2) has the same crystal structure as the MgZn2 Laves phase. It forms at pressures between 4.3 and 220 GPa, though Raman measurements suggest that the H2 molecules in Ar(H2)2 dissociate above 175 GPa. Production. Argon is extracted industrially by the fractional distillation of liquid air in a cryogenic air separation unit; a process that separates liquid nitrogen, which boils at 77.3 K, from argon, which boils at 87.3 K, and liquid oxygen, which boils at 90.2 K. About 700,000 tonnes of argon are produced worldwide every year. Applications. Argon has several desirable properties: Other noble gases would be equally suitable for most of these applications, but argon is by far the cheapest. It is inexpensive, since it occurs naturally in air and is readily obtained as a byproduct of cryogenic air separation in the production of liquid oxygen and liquid nitrogen: the primary constituents of air are used on a large industrial scale. The other noble gases (except helium) are produced this way as well, but argon is the most plentiful by far. The bulk of its applications arise simply because it is inert and relatively cheap.
Industrial processes. Argon is used in some high-temperature industrial processes where ordinarily non-reactive substances become reactive. For example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. For some of these processes, the presence of nitrogen or oxygen gases might cause defects within the material. Argon is used in some types of arc welding such as gas metal arc welding and gas tungsten arc welding, as well as in the processing of titanium and other reactive elements. An argon atmosphere is also used for growing crystals of silicon and germanium. Argon is used in the poultry industry to asphyxiate birds, either for mass culling following disease outbreaks, or as a means of slaughter more humane than electric stunning. Argon is denser than air and displaces oxygen close to the ground during inert gas asphyxiation. Its non-reactive nature makes it suitable in a food product, and since it replaces oxygen within the dead bird, argon also enhances shelf life.
Argon is sometimes used for extinguishing fires where valuable equipment may be damaged by water or foam. Scientific research. Liquid argon is used as the target for neutrino experiments and direct dark matter searches. The interaction between the hypothetical WIMPs and an argon nucleus produces scintillation light that is detected by photomultiplier tubes. Two-phase detectors containing argon gas are used to detect the ionized electrons produced during the WIMP–nucleus scattering. As with most other liquefied noble gases, argon has a high scintillation light yield (about 51 photons/keV), is transparent to its own scintillation light, and is relatively easy to purify. Compared to xenon, argon is cheaper and has a distinct scintillation time profile, which allows the separation of electronic recoils from nuclear recoils. On the other hand, its intrinsic beta-ray background is larger due to contamination, unless one uses argon from underground sources, which has much less contamination. Most of the argon in Earth's atmosphere was produced by electron capture of long-lived ( + e− → + ν) present in natural potassium within Earth. The activity in the atmosphere is maintained by cosmogenic production through the knockout reaction (n,2n) and similar reactions. The half-life of is only 269 years. As a result, the underground Ar, shielded by rock and water, has much less contamination. Dark-matter detectors currently operating with liquid argon include DarkSide, WArP, ArDM, microCLEAN and DEAP. Neutrino experiments include ICARUS and MicroBooNE, both of which use high-purity liquid argon in a time projection chamber for fine grained three-dimensional imaging of neutrino interactions.
At Linköping University, Sweden, the inert gas is being utilized in a vacuum chamber in which plasma is introduced to ionize metallic films. This process results in a film usable for manufacturing computer processors. The new process would eliminate the need for chemical baths and use of expensive, dangerous and rare materials. Preservative. Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the European food additive code E938). Aerial oxidation, hydrolysis, and other chemical reactions that degrade the products are retarded or prevented entirely. High-purity chemicals and pharmaceuticals are sometimes packed and sealed in argon. In winemaking, argon is used in a variety of activities to provide a barrier against oxygen at the liquid surface, which can spoil wine by fueling both microbial metabolism (as with acetic acid bacteria) and standard redox chemistry. Argon is sometimes used as the propellant in aerosol cans. Argon is also used as a preservative for such products as varnish, polyurethane, and paint, by displacing air to prepare a container for storage.
Since 2002, the American National Archives stores important national documents such as the Declaration of Independence and the Constitution within argon-filled cases to inhibit their degradation. Argon is preferable to the helium that had been used in the preceding five decades, because helium gas escapes through the intermolecular pores in most containers and must be regularly replaced. Laboratory equipment. Argon may be used as the inert gas within Schlenk lines and gloveboxes. Argon is preferred to less expensive nitrogen in cases where nitrogen may react with the reagents or apparatus. Argon may be used as the carrier gas in gas chromatography and in electrospray ionization mass spectrometry; it is the gas of choice for the plasma used in ICP spectroscopy. Argon is preferred for the sputter coating of specimens for scanning electron microscopy. Argon gas is also commonly used for sputter deposition of thin films as in microelectronics and for wafer cleaning in microfabrication. Medical use. Cryosurgery procedures such as cryoablation use liquid argon to destroy tissue such as cancer cells. It is used in a procedure called "argon-enhanced coagulation", a form of argon plasma beam electrosurgery. The procedure carries a risk of producing gas embolism and has resulted in the death of at least one patient.
Blue argon lasers are used in surgery to weld arteries, destroy tumors, and correct eye defects. Argon has also been used experimentally to replace nitrogen in the breathing or decompression mix known as Argox, to speed the elimination of dissolved nitrogen from the blood. Lighting. Incandescent lights are filled with argon, to preserve the filaments at high temperature from oxidation. It is used for the specific way it ionizes and emits light, such as in plasma globes and calorimetry in experimental particle physics. Gas-discharge lamps filled with pure argon provide lilac/violet light; with argon and some mercury, blue light. Argon is also used for blue and green argon-ion lasers. Miscellaneous uses. Argon is used for thermal insulation in energy-efficient windows. Argon is also used in technical scuba diving to inflate a dry suit because it is inert and has low thermal conductivity. Argon is used as a propellant in the development of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). Compressed argon gas is allowed to expand, to cool the seeker heads of some versions of the AIM-9 Sidewinder missile and other missiles that use cooled thermal seeker heads. The gas is stored at high pressure.
Argon-39, with a half-life of 269 years, has been used for a number of applications, primarily ice core and ground water dating. Also, potassium–argon dating and related argon-argon dating are used to date sedimentary, metamorphic, and igneous rocks. Argon has been used by athletes as a doping agent to simulate hypoxic conditions. In 2014, the World Anti-Doping Agency (WADA) added argon and xenon to the list of prohibited substances and methods, although at this time there is no reliable test for abuse. Safety. Although argon is non-toxic, it is 38% more dense than air and therefore considered a dangerous asphyxiant in closed areas. It is difficult to detect because it is colorless, odorless, and tasteless. A 1994 incident, in which a man was asphyxiated after entering an argon-filled section of oil pipe under construction in Alaska, highlights the dangers of argon tank leakage in confined spaces and emphasizes the need for proper use, storage and handling.
Arsenic Arsenic is a chemical element; it has symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is notoriously toxic. It occurs naturally in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. It has various allotropes, but only the grey form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is also a common n-type dopant in semiconductor electronic devices, and a component of the III–V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the increasing recognition of the persistent toxicity of arsenic and its compounds. Arsenic has been known since ancient times to be poisonous to humans. However, a few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic have been proposed to be an essential dietary element in rats, hamsters, goats, and chickens. Research has not been conducted to determine whether small amounts of arsenic may play a role in human metabolism. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed. Arsenic contamination of groundwater is a problem that affects millions of people across the world.
The United States' Environmental Protection Agency states that all forms of arsenic are a serious risk to human health. The United States Agency for Toxic Substances and Disease Registry ranked arsenic number 1 in its 2001 prioritized list of hazardous substances at Superfund sites. Arsenic is classified as a group-A carcinogen. Characteristics. Physical characteristics. The three most common arsenic allotropes are grey, yellow, and black arsenic, with grey being the most common. Grey arsenic (α-As, space group Rm No. 166) adopts a double-layered structure consisting of many interlocked, ruffled, six-membered rings. Because of weak bonding between the layers, grey arsenic is brittle and has a relatively low Mohs hardness of 3.5. Nearest and next-nearest neighbors form a distorted octahedral complex, with the three atoms in the same double-layer being slightly closer than the three atoms in the next. This relatively close packing leads to a high density of 5.73 g/cm3. Grey arsenic is a semimetal, but becomes a semiconductor with a bandgap of 1.2–1.4 eV if amorphized. Grey arsenic is also the most stable form.
Yellow arsenic is soft and waxy, and somewhat similar to tetraphosphorus (). Both have four atoms arranged in a tetrahedral structure in which each atom is bound to each of the other three atoms by a single bond. This unstable allotrope, being molecular, is the most volatile, least dense, and most toxic. Solid yellow arsenic is produced by rapid cooling of arsenic vapor, . It is rapidly transformed into grey arsenic by light. The yellow form has a density of 1.97 g/cm3. Black arsenic is similar in structure to black phosphorus. Black arsenic can also be formed by cooling vapor at around 100–220 °C and by crystallization of amorphous arsenic in the presence of mercury vapors. It is glassy and brittle. Black arsenic is also a poor electrical conductor. Arsenic sublimes upon heating at atmospheric pressure, converting directly to a gaseous form without an intervening liquid state at . The triple point is at 3.63 MPa and . Isotopes. Arsenic occurs in nature as one stable isotope, 75As, and is therefore called a monoisotopic element. As of 2024, at least 32 radioisotopes have also been synthesized, ranging in atomic mass from 64–95. The most stable of these is 73As with a half-life of 80.30 days. The majority of the other isotopes have half-lives of under one day, with the exceptions being
Isotopes that are lighter than the stable 75As tend to decay by β+ decay, and those that are heavier tend to decay by β− decay, with some exceptions. At least 10 nuclear isomers have been described, ranging in atomic mass from 66 to 84. The most stable of arsenic's isomers is 68mAs with a half-life of 111 seconds. Chemistry. Arsenic has a similar electronegativity and ionization energies to its lighter pnictogen congener phosphorus and therefore readily forms covalent molecules with most of the nonmetals. Though stable in dry air, arsenic forms a golden-bronze tarnish upon exposure to humidity which eventually becomes a black surface layer. When heated in air, arsenic oxidizes to arsenic trioxide; the fumes from this reaction have an odor resembling garlic. This odor can be detected on striking arsenide minerals such as arsenopyrite with a hammer. It burns in oxygen to form arsenic trioxide and arsenic pentoxide, which have the same structure as the more well-known phosphorus compounds, and in fluorine to give arsenic pentafluoride. Arsenic makes arsenic acid with concentrated nitric acid, arsenous acid with dilute nitric acid, and arsenic trioxide with concentrated sulfuric acid; however, it does not react with water, alkalis, or non-oxidising acids. Arsenic reacts with metals to form arsenides, though these are not ionic compounds containing the As3− ion as the formation of such an anion would be highly endothermic and even the group 1 arsenides have properties of intermetallic compounds. Like germanium, selenium, and bromine, which like arsenic succeed the 3d transition series, arsenic is much less stable in the +5 oxidation state than its vertical neighbors phosphorus and antimony, and hence arsenic pentoxide and arsenic acid are potent oxidizers.
Compounds. Compounds of arsenic resemble, in some respects, those of phosphorus, which occupies the same group (column) of the periodic table. The most common oxidation states for arsenic are: −3 in the arsenides, which are alloy-like intermetallic compounds, +3 in the arsenites, and +5 in the arsenates and most organoarsenic compounds. Arsenic also bonds readily to itself as seen in the square ions in the mineral skutterudite. In the +3 oxidation state, arsenic is typically pyramidal owing to the influence of the lone pair of electrons. Inorganic compounds. One of the simplest arsenic compounds is the trihydride, the highly toxic, flammable, pyrophoric arsine (AsH3). This compound is generally regarded as stable, since at room temperature it decomposes only slowly. At temperatures of 250–300 °C decomposition to arsenic and hydrogen is rapid. Several factors, such as humidity, presence of light and certain catalysts (namely aluminium) facilitate the rate of decomposition. It oxidises readily in air to form arsenic trioxide and water, and analogous reactions take place with sulfur and selenium instead of oxygen.
Arsenic forms colorless, odorless, crystalline oxides As2O3 ("white arsenic") and As2O5 which are hygroscopic and readily soluble in water to form acidic solutions. Arsenic(V) acid is a weak acid and its salts, known as arsenates, are a major source of arsenic contamination of groundwater in regions with high levels of naturally-occurring arsenic minerals. Synthetic arsenates include Scheele's Green (cupric hydrogen arsenate, acidic copper arsenate), calcium arsenate, and lead hydrogen arsenate. These three have been used as agricultural insecticides and poisons. The protonation steps between the arsenate and arsenic acid are similar to those between phosphate and phosphoric acid. Unlike phosphorous acid, arsenous acid is genuinely tribasic, with the formula As(OH)3. A broad variety of sulfur compounds of arsenic are known. Orpiment (As2S3) and realgar (As4S4) are somewhat abundant and were formerly used as painting pigments. In As4S10, arsenic has a formal oxidation state of +2 in As4S4 which features As-As bonds so that the total covalency of As is still 3. Both orpiment and realgar, as well as As4S3, have selenium analogs; the analogous As2Te3 is known as the mineral kalgoorlieite, and the anion As2Te− is known as a ligand in cobalt complexes.
All trihalides of arsenic(III) are well known except the astatide, which is unknown. Arsenic pentafluoride (AsF5) is the only important pentahalide, reflecting the lower stability of the +5 oxidation state; even so, it is a very strong fluorinating and oxidizing agent. (The pentachloride is stable only below −50 °C, at which temperature it decomposes to the trichloride, releasing chlorine gas.) Alloys. Arsenic is used as the group 5 element in the III-V semiconductors gallium arsenide, indium arsenide, and aluminium arsenide. The valence electron count of GaAs is the same as a pair of Si atoms, but the band structure is completely different which results in distinct bulk properties. Other arsenic alloys include the II-V semiconductor cadmium arsenide. Organoarsenic compounds. A large variety of organoarsenic compounds are known. Several were developed as chemical warfare agents during World War I, including vesicants such as lewisite and vomiting agents such as adamsite. Cacodylic acid, which is of historic and practical interest, arises from the methylation of arsenic trioxide, a reaction that has no analogy in phosphorus chemistry. Cacodyl was the first organometallic compound known (even though arsenic is not a true metal) and was named from the Greek "κακωδία" "stink" for its offensive, garlic-like odor; it is very toxic.
Occurrence and production. Arsenic is the 53rd most abundant element in the Earth's crust, comprising about 1.5 parts per million (0.00015%). Typical background concentrations of arsenic do not exceed 3 ng/m3 in the atmosphere; 100 mg/kg in soil; 400 μg/kg in vegetation; 10 μg/L in freshwater and 1.5 μg/L in seawater. Arsenic is the 22nd most abundant element in seawater and ranks 41st in abundance in the universe. Minerals with the formula MAsS and MAs2 (M = Fe, Ni, Co) are the dominant commercial sources of arsenic, together with realgar (an arsenic sulfide mineral) and native (elemental) arsenic. An illustrative mineral is arsenopyrite (FeAsS), which is structurally related to iron pyrite. Many minor As-containing minerals are known. Arsenic also occurs in various organic forms in the environment. In 2014, China was the top producer of white arsenic with almost 70% world share, followed by Morocco, Russia, and Belgium, according to the British Geological Survey and the United States Geological Survey. Most arsenic refinement operations in the US and Europe have closed over environmental concerns. Arsenic is found in the smelter dust from copper, gold, and lead smelters, and is recovered primarily from copper refinement dust. Arsenic is the main of impurity found in copper concentrates to enter copper smelting facilities. There has been an increase in arsenic in copper concentrates over the years since copper mining has moved into deep high-impurity ores as shallow, low-arsenic copper deposits have been progressively depleted.
On roasting arsenopyrite in air, arsenic sublimes as arsenic(III) oxide leaving iron oxides, while roasting without air results in the production of gray arsenic. Further purification from sulfur and other chalcogens is achieved by sublimation in vacuum, in a hydrogen atmosphere, or by distillation from molten lead-arsenic mixture. History. The word "arsenic" has its origin in the Syriac word "zarnika", from Arabic al-zarnīḵ 'the orpiment', based on Persian zar ("gold") from the word "zarnikh", meaning "yellow" (literally "gold-colored") and hence "(yellow) orpiment". It was adopted into Greek (using folk etymology) as "arsenikon" () – a neuter form of the Greek adjective "arsenikos" (), meaning "male", "virile". Latin-speakers adopted the Greek term as , which in French ultimately became , whence the English word "arsenic". Arsenic sulfides (orpiment, realgar) and oxides have been known and used since ancient times. Zosimos () describes roasting "sandarach" (realgar) to obtain "cloud of arsenic" (arsenic trioxide), which he then reduces to gray arsenic. As the symptoms of arsenic poisoning are not very specific, the substance was frequently used for murder until the advent in the 1830s of the Marsh test, a sensitive chemical test for its presence. (Another less sensitive but more general test is the Reinsch test.) Owing to its use by the ruling class to murder one another and its potency and discreetness, arsenic has been called the "poison of kings" and the "king of poisons". Arsenic became known as "the inheritance powder" due to its use in killing family members in the Renaissance era.
During the Bronze Age, arsenic was melted with copper to make arsenical bronze. Jabir ibn Hayyan described the isolation of arsenic before 815 AD. Albertus Magnus (Albert the Great, 1193–1280) later isolated the element from a compound in 1250, by heating soap together with arsenic trisulfide. In 1649, Johann Schröder published two ways of preparing arsenic. Crystals of elemental (native) arsenic are found in nature, although rarely. Cadet's fuming liquid (impure cacodyl), often claimed as the first synthetic organometallic compound, was synthesized in 1760 by Louis Claude Cadet de Gassicourt through the reaction of potassium acetate with arsenic trioxide. In the Victorian era, women would eat "arsenic" ("white arsenic" or arsenic trioxide) mixed with vinegar and chalk to improve the complexion of their faces, making their skin paler (to show they did not work in the fields). The accidental use of arsenic in the adulteration of foodstuffs led to the Bradford sweet poisoning in 1858, which resulted in 21 deaths. From the late 18th century wallpaper production began to use dyes made from arsenic,
which was thought to increase the pigment's brightness. One account of the illness and 1821 death of Napoleon implicates arsenic poisoning involving wallpaper. Two arsenic pigments have been widely used since their discovery – Paris Green in 1814 and Scheele's Green in 1775. After the toxicity of arsenic became widely known, these chemicals were used less often as pigments and more often as insecticides. In the 1860s, an arsenic byproduct of dye production, London Purple, was widely used. This was a solid mixture of arsenic trioxide, aniline, lime, and ferrous oxide, insoluble in water and very toxic by inhalation or ingestion But it was later replaced with Paris Green, another arsenic-based dye. With better understanding of the toxicology mechanism, two other compounds were used starting in the 1890s. Arsenite of lime and arsenate of lead were used widely as insecticides until the discovery of DDT in 1942. In small doses, soluble arsenic compounds act as stimulants, and were once popular as medicine by people in the mid-18th to 19th centuries; this use was especially prevalent for sport animals such as race horses or work dogs and continued into the 20th century.
A 2006 study of the remains of the Australian racehorse Phar Lap determined that its 1932 death was caused by a massive overdose of arsenic. Sydney veterinarian Percy Sykes stated, Applications. Agricultural. The toxicity of arsenic to insects, bacteria, and fungi led to its use as a wood preservative. In the 1930s, a process of treating wood with chromated copper arsenate (also known as CCA or Tanalith) was invented, and for decades, this treatment was the most extensive industrial use of arsenic. An increased appreciation of the toxicity of arsenic led to a ban of CCA in consumer products in 2004, initiated by the European Union and United States. However, CCA remains in heavy use in other countries (such as on Malaysian rubber plantations). Arsenic was also used in various agricultural insecticides and poisons. For example, lead hydrogen arsenate was a common insecticide on fruit trees, but contact with the compound sometimes resulted in brain damage among those working the sprayers. In the second half of the 20th century, monosodium methyl arsenate (MSMA) and disodium methyl arsenate (DSMA) – less toxic organic forms of arsenic – replaced lead arsenate in agriculture. These organic arsenicals were in turn phased out in the United States by 2013 in all agricultural activities except cotton farming.
The biogeochemistry of arsenic is complex and includes various adsorption and desorption processes. The toxicity of arsenic is connected to its solubility and is affected by pH. Arsenite () is more soluble than arsenate () and is more toxic; however, at a lower pH, arsenate becomes more mobile and toxic. It was found that addition of sulfur, phosphorus, and iron oxides to high-arsenite soils greatly reduces arsenic phytotoxicity. Arsenic is used as a feed additive in poultry and swine production, in particular it was used in the U.S. until 2015 to increase weight gain, improve feed efficiency, and prevent disease. An example is roxarsone, which had been used as a broiler starter by about 70% of U.S. broiler growers. In 2011, Alpharma, a subsidiary of Pfizer Inc., which produces roxarsone, voluntarily suspended sales of the drug in response to studies showing elevated levels of inorganic arsenic, a carcinogen, in treated chickens. A successor to Alpharma, Zoetis, continued to sell nitarsone until 2015, primarily for use in turkeys.
Medical use. During the 17th, 18th, and 19th centuries, a number of arsenic compounds were used as medicines, including arsphenamine (by Paul Ehrlich) and arsenic trioxide (by Thomas Fowler), for treating diseases such as cancer or psoriasis. Arsphenamine, as well as neosalvarsan, was indicated for syphilis, but has been superseded by modern antibiotics. However, arsenicals such as melarsoprol are still used for the treatment of trypanosomiasis in spite of their severe toxicity, since the disease is almost uniformly fatal if untreated. In 2000 the US Food and Drug Administration approved arsenic trioxide for the treatment of patients with acute promyelocytic leukemia that is resistant to all-trans retinoic acid. A 2008 paper reports success in locating tumors using arsenic-74 (a positron emitter). This isotope produces clearer PET scan images than the previous radioactive agent, iodine-124, because the body tends to transport iodine to the thyroid gland producing signal noise. Nanoparticles of arsenic have shown ability to kill cancer cells with lesser cytotoxicity than other arsenic formulations.
Alloys. The main use of arsenic is in alloying with lead. Lead components in car batteries are strengthened by the presence of a very small percentage of arsenic. Dezincification of brass (a copper-zinc alloy) is greatly reduced by the addition of arsenic. "Phosphorus Deoxidized Arsenical Copper" with an arsenic content of 0.3% has an increased corrosion stability in certain environments. Gallium arsenide is an important semiconductor material, used in integrated circuits. Circuits made from GaAs are much faster (but also much more expensive) than those made from silicon. Unlike silicon, GaAs has a direct bandgap, and can be used in laser diodes and LEDs to convert electrical energy directly into light. Military. After World War I, the United States built a stockpile of 20,000 tons of weaponized lewisite (ClCH=CHAsCl2), an organoarsenic vesicant (blister agent) and lung irritant. The stockpile was neutralized with bleach and dumped into the Gulf of Mexico in the 1950s. Lewisite, the chemical warfare agent, is known for its acute toxicity to aquatic organisms. However, studies assessing the environmental impact of this disposal in the Gulf are lacking. During the Vietnam War, the United States used Agent Blue, a mixture of sodium cacodylate and its acid form, as one of the rainbow herbicides to deprive North Vietnamese soldiers of foliage cover and rice.
Biological role. Bacteria. Some species of bacteria obtain their energy in the absence of oxygen by oxidizing various fuels while reducing arsenate to arsenite. Under oxidative environmental conditions some bacteria use arsenite as fuel, which they oxidize to arsenate. The enzymes involved are known as arsenate reductases (Arr). In 2008, bacteria were discovered that employ a version of photosynthesis in the absence of oxygen with arsenites as electron donors, producing arsenates (just as ordinary photosynthesis uses water as electron donor, producing molecular oxygen). Researchers conjecture that, over the course of history, these photosynthesizing organisms produced the arsenates that allowed the arsenate-reducing bacteria to thrive. One strain, PHS-1, has been isolated and is related to the gammaproteobacterium "Ectothiorhodospira shaposhnikovii". The mechanism is unknown, but an encoded Arr enzyme may function in reverse to its known homologues. In 2011, it was postulated that the "Halomonadaceae" strain GFAJ-1 could be grown in the absence of phosphorus if that element were substituted with arsenic, exploiting the fact that the arsenate and phosphate anions are similar structurally. The study was widely criticised and subsequently refuted by independent research groups.
Potential role in higher animals. Arsenic may be an essential trace mineral in birds, involved in the synthesis of methionine metabolites. However, the role of arsenic in bird nutrition is disputed, as other authors state that arsenic is toxic in small amounts. Some evidence indicates that arsenic is an essential trace mineral in mammals. Heredity. Arsenic has been linked to epigenetic changes, heritable changes in gene expression that occur without changes in DNA sequence. These include DNA methylation, histone modification, and RNA interference. Toxic levels of arsenic cause significant DNA hypermethylation of tumor suppressor genes p16 and p53, thus increasing risk of carcinogenesis. These epigenetic events have been studied "in vitro" using human kidney cells and "in vivo" using rat liver cells and peripheral blood leukocytes in humans. Inductively coupled plasma mass spectrometry (ICP-MS) is used to detect precise levels of intracellular arsenic and other arsenic bases involved in epigenetic modification of DNA. Studies investigating arsenic as an epigenetic factor can be used to develop precise biomarkers of exposure and susceptibility.
The Chinese brake fern ("Pteris vittata") hyperaccumulates arsenic from the soil into its leaves and has a proposed use in phytoremediation. Biomethylation. Inorganic arsenic and its compounds, upon entering the food chain, are progressively metabolized through a process of methylation. For example, the mold "Scopulariopsis brevicaulis" produces trimethylarsine if inorganic arsenic is present. The organic compound arsenobetaine is found in some marine foods such as fish and algae, and also in mushrooms in larger concentrations. The average person's intake is about 10–50 μg/day. Values about 1000 μg are not unusual following consumption of fish or mushrooms, but there is little danger in eating fish because this arsenic compound is nearly non-toxic. Environmental issues. Exposure. Naturally occurring sources of human exposure include volcanic ash, weathering of minerals and ores, and mineralized groundwater. Arsenic is also found in food, water, soil, and air. Arsenic is absorbed by all plants, but is more concentrated in leafy vegetables, rice, apple and grape juice, and seafood. An additional route of exposure is inhalation of atmospheric gases and dusts.
During the Victorian era, arsenic was widely used in home decor, especially wallpapers. In Europe, an analysis based on 20,000 soil samples across all 28 countries show that 98% of sampled soils have concentrations less than 20 mg/kg. In addition, the arsenic hotspots are related to both frequent fertilization and close distance to mining activities. Chronic exposure to arsenic, particularly through contaminated drinking water and food, has also been linked to long-term impacts on cognitive function, including reduced verbal IQ and memory. Occurrence in drinking water. Extensive arsenic contamination of groundwater has led to widespread arsenic poisoning in Bangladesh and neighboring countries. It is estimated that approximately 57 million people in the Bengal basin are drinking groundwater with arsenic concentrations elevated above the World Health Organization's standard of 10 parts per billion (ppb). However, a study of cancer rates in Taiwan suggested that significant increases in cancer mortality appear only at levels above 150 ppb.
It is estimated that approximately 57 million people in the Bengal basin are drinking groundwater with arsenic concentrations elevated above the World Health Organization's standard of 10 parts per billion (ppb). However, a study of cancer rates in Taiwan suggested that significant increases in cancer mortality appear only at levels above 150 ppb. The arsenic in the groundwater is of natural origin, and is released from the sediment into the groundwater, caused by the anoxic conditions of the subsurface. This groundwater was used after local and western NGOs and the Bangladeshi government undertook a massive shallow tube well drinking-water program in the late twentieth century. This program was designed to prevent drinking of bacteria-contaminated surface waters, but failed to test for arsenic in the groundwater. Many other countries and districts in Southeast Asia, such as Vietnam and Cambodia, have geological environments that produce groundwater with a high arsenic content.
Many other countries and districts in Southeast Asia, such as Vietnam and Cambodia, have geological environments that produce groundwater with a high arsenic content. In Pakistan, more than 60 million people are exposed to arsenic polluted drinking water indicated by a 2017 report in "Science". Podgorski's team investigated more than 1200 samples and more than 66% exceeded the WHO contamination limits of 10 micrograms per liter. Since the 1980s, residents of the Ba Men region of Inner Mongolia, China have been chronically exposed to arsenic through drinking water from contaminated wells. A 2009 research study observed an elevated presence of skin lesions among residents with well water arsenic concentrations between 5 and 10 μg/L, suggesting that arsenic-induced toxicity may occur at relatively low concentrations with chronic exposure. Overall, 20 of China's 34 provinces have high arsenic concentrations in the groundwater supply, potentially exposing 19 million people to hazardous drinking water. A study by IIT Kharagpur found high levels of Arsenic in groundwater of 20% of India's land, exposing more than 250 million people. States such as Punjab, Bihar, West Bengal, Assam, Haryana, Uttar Pradesh, and Gujarat have highest land area exposed to arsenic.
In the United States, arsenic is most commonly found in the ground waters of the southwest. Parts of New England, Michigan, Wisconsin, Minnesota and the Dakotas are also known to have significant concentrations of arsenic in ground water. Increased levels of skin cancer have been associated with arsenic exposure in Wisconsin, even at levels below the 10 ppb drinking water standard. According to a recent film funded by the US Superfund, millions of private wells have unknown arsenic levels, and in some areas of the US, more than 20% of the wells may contain levels that exceed established limits. Low-level exposure to arsenic at concentrations of 100 ppb (i.e., above the 10 ppb drinking water standard) compromises the initial immune response to H1N1 or swine flu infection according to NIEHS-supported scientists. The study, conducted in laboratory mice, suggests that people exposed to arsenic in their drinking water may be at increased risk for more serious illness or death from the virus. Some Canadians are drinking water that contains inorganic arsenic. Private-dug–well waters are most at risk for containing inorganic arsenic. Preliminary well water analysis typically does not test for arsenic. Researchers at the Geological Survey of Canada have modeled relative variation in natural arsenic hazard potential for the province of New Brunswick. This study has important implications for potable water and health concerns relating to inorganic arsenic.
Epidemiological evidence from Chile shows a dose-dependent connection between chronic arsenic exposure and various forms of cancer, in particular when other risk factors, such as cigarette smoking, are present. These effects have been demonstrated at contaminations less than 50 ppb. Arsenic is itself a constituent of tobacco smoke. Analyzing multiple epidemiological studies on inorganic arsenic exposure suggests a small but measurable increase in risk for bladder cancer at 10 ppb. According to Peter Ravenscroft of the Department of Geography at the University of Cambridge, roughly 80 million people worldwide consume between 10 and 50 ppb arsenic in their drinking water. If they all consumed exactly 10 ppb arsenic in their drinking water, the previously cited multiple epidemiological study analysis would predict an additional 2,000 cases of bladder cancer alone. This represents a clear underestimate of the overall impact, since it does not include lung or skin cancer, and explicitly underestimates the exposure. Those exposed to levels of arsenic above the current WHO standard should weigh the costs and benefits of arsenic remediation.
Early (1973) evaluations of the processes for removing dissolved arsenic from drinking water demonstrated the efficacy of co-precipitation with either iron or aluminium oxides. In particular, iron as a coagulant was found to remove arsenic with an efficacy exceeding 90%. Several adsorptive media systems have been approved for use at point-of-service in a study funded by the United States Environmental Protection Agency (US EPA) and the National Science Foundation (NSF). A team of European and Indian scientists and engineers have set up six arsenic treatment plants in West Bengal based on in-situ remediation method (SAR Technology). This technology does not use any chemicals and arsenic is left in an insoluble form (+5 state) in the subterranean zone by recharging aerated water into the aquifer and developing an oxidation zone that supports arsenic oxidizing micro-organisms. This process does not produce any waste stream or sludge and is relatively cheap. Another effective and inexpensive method to avoid arsenic contamination is to sink wells 500 feet or deeper to reach purer waters. A recent 2011 study funded by the US National Institute of Environmental Health Sciences' Superfund Research Program shows that deep sediments can remove arsenic and take it out of circulation. In this process, called "adsorption", arsenic sticks to the surfaces of deep sediment particles and is naturally removed from the ground water.
Magnetic separations of arsenic at very low magnetic field gradients with high-surface-area and monodisperse magnetite (Fe3O4) nanocrystals have been demonstrated in point-of-use water purification. Using the high specific surface area of Fe3O4 nanocrystals, the mass of waste associated with arsenic removal from water has been dramatically reduced. Epidemiological studies have suggested a correlation between chronic consumption of drinking water contaminated with arsenic and the incidence of all leading causes of mortality. The literature indicates that arsenic exposure is causative in the pathogenesis of diabetes. Chaff-based filters have recently been shown to reduce the arsenic content of water to 3 μg/L. This may find applications in areas where the potable water is extracted from underground aquifers. San Pedro de Atacama. For several centuries, the people of San Pedro de Atacama in Chile have been drinking water that is contaminated with arsenic, and some evidence suggests they have developed some immunity.
Hazard maps for contaminated groundwater. Around one-third of the world's population drinks water from groundwater resources. Of this, about 10 percent, approximately 300 million people, obtains water from groundwater resources that are contaminated with unhealthy levels of arsenic or fluoride. These trace elements derive mainly from minerals and ions in the ground. Redox transformation of arsenic in natural waters. Arsenic is unique among the trace metalloids and oxyanion-forming trace metals (e.g. As, Se, Sb, Mo, V, Cr, U, Re). It is sensitive to mobilization at pH values typical of natural waters (pH 6.5–8.5) under both oxidizing and reducing conditions. Arsenic can occur in the environment in several oxidation states (−3, 0, +3 and +5), but in natural waters it is mostly found in inorganic forms as oxyanions of trivalent arsenite [As(III)] or pentavalent arsenate [As(V)]. Organic forms of arsenic are produced by biological activity, mostly in surface waters, but are rarely quantitatively important. Organic arsenic compounds may, however, occur where waters are significantly impacted by industrial pollution.
Arsenic may be solubilized by various processes. When pH is high, arsenic may be released from surface binding sites that lose their positive charge. When water level drops and sulfide minerals are exposed to air, arsenic trapped in sulfide minerals can be released into water. When organic carbon is present in water, bacteria are fed by directly reducing As(V) to As(III) or by reducing the element at the binding site, releasing inorganic arsenic. The aquatic transformations of arsenic are affected by pH, reduction-oxidation potential, organic matter concentration and the concentrations and forms of other elements, especially iron and manganese. The main factors are pH and the redox potential. Generally, the main forms of arsenic under oxic conditions are , , , and at pH 2, 2–7, 7–11 and 11, respectively. Under reducing conditions, is predominant at pH 2–9. Oxidation and reduction affects the migration of arsenic in subsurface environments. Arsenite is the most stable soluble form of arsenic in reducing environments and arsenate, which is less mobile than arsenite, is dominant in oxidizing environments at neutral pH. Therefore, arsenic may be more mobile under reducing conditions. The reducing environment is also rich in organic matter which may enhance the solubility of arsenic compounds. As a result, the adsorption of arsenic is reduced and dissolved arsenic accumulates in groundwater. That is why the arsenic content is higher in reducing environments than in oxidizing environments.
The presence of sulfur is another factor that affects the transformation of arsenic in natural water. Arsenic can precipitate when metal sulfides form. In this way, arsenic is removed from the water and its mobility decreases. When oxygen is present, bacteria oxidize reduced sulfur to generate energy, potentially releasing bound arsenic. Redox reactions involving Fe also appear to be essential factors in the fate of arsenic in aquatic systems. The reduction of iron oxyhydroxides plays a key role in the release of arsenic to water. So arsenic can be enriched in water with elevated Fe concentrations. Under oxidizing conditions, arsenic can be mobilized from pyrite or iron oxides especially at elevated pH. Under reducing conditions, arsenic can be mobilized by reductive desorption or dissolution when associated with iron oxides. The reductive desorption occurs under two circumstances. One is when arsenate is reduced to arsenite which adsorbs to iron oxides less strongly. The other results from a change in the charge on the mineral surface which leads to the desorption of bound arsenic.
Some species of bacteria catalyze redox transformations of arsenic. Dissimilatory arsenate-respiring prokaryotes (DARP) speed up the reduction of As(V) to As(III). DARP use As(V) as the electron acceptor of anaerobic respiration and obtain energy to survive. Other organic and inorganic substances can be oxidized in this process. Chemoautotrophic arsenite oxidizers (CAO) and heterotrophic arsenite oxidizers (HAO) convert As(III) into As(V). CAO combine the oxidation of As(III) with the reduction of oxygen or nitrate. They use obtained energy to fix produce organic carbon from CO2. HAO cannot obtain energy from As(III) oxidation. This process may be an arsenic detoxification mechanism for the bacteria. Equilibrium thermodynamic calculations predict that As(V) concentrations should be greater than As(III) concentrations in all but strongly reducing conditions, i.e. where sulfate reduction is occurring. However, abiotic redox reactions of arsenic are slow. Oxidation of As(III) by dissolved O2 is a particularly slow reaction. For example, Johnson and Pilson (1975) gave half-lives for the oxygenation of As(III) in seawater ranging from several months to a year. In other studies, As(V)/As(III) ratios were stable over periods of days or weeks during water sampling when no particular care was taken to prevent oxidation, again suggesting relatively slow oxidation rates. Cherry found from experimental studies that the As(V)/As(III) ratios were stable in anoxic solutions for up to 3 weeks but that gradual changes occurred over longer timescales. Sterile water samples have been observed to be less susceptible to speciation changes than non-sterile samples. Oremland found that the reduction of As(V) to As(III) in Mono Lake was rapidly catalyzed by bacteria with rate constants ranging from 0.02 to 0.3-day−1.
Wood preservation in the US. As of 2002, US-based industries consumed 19,600 metric tons of arsenic. Ninety percent of this was used for treatment of wood with chromated copper arsenate (CCA). In 2007, 50% of the 5,280 metric tons of consumption was still used for this purpose. In the United States, the voluntary phasing-out of arsenic in production of consumer products and residential and general consumer construction products began on 31 December 2003, and alternative chemicals are now used, such as Alkaline Copper Quaternary, borates, copper azole, cyproconazole, and propiconazole. Although discontinued, this application is also one of the most concerning to the general public. The vast majority of older pressure-treated wood was treated with CCA. CCA lumber is still in widespread use in many countries, and was heavily used during the latter half of the 20th century as a structural and outdoor building material. Although the use of CCA lumber was banned in many areas after studies showed that arsenic could leach out of the wood into the surrounding soil (from playground equipment, for instance), a risk is also presented by the burning of older CCA timber. The direct or indirect ingestion of wood ash from burnt CCA lumber has caused fatalities in animals and serious poisonings in humans; the lethal human dose is approximately 20 grams of ash. Scrap CCA lumber from construction and demolition sites may be inadvertently used in commercial and domestic fires. Protocols for safe disposal of CCA lumber are not consistent throughout the world. Widespread landfill disposal of such timber raises some concern, but other studies have shown no arsenic contamination in the groundwater.
Mapping of industrial releases in the US. One tool that maps the location (and other information) of arsenic releases in the United States is TOXMAP. TOXMAP is a Geographic Information System (GIS) from the Division of Specialized Information Services of the United States National Library of Medicine (NLM) funded by the US Federal Government. With marked-up maps of the United States, TOXMAP enables users to visually explore data from the United States Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund Basic Research Programs. TOXMAP's chemical and environmental health information is taken from NLM's Toxicology Data Network (TOXNET), PubMed, and from other authoritative sources. Bioremediation. Physical, chemical, and biological methods have been used to remediate arsenic contaminated water. Bioremediation is said to be cost-effective and environmentally friendly. Bioremediation of ground water contaminated with arsenic aims to convert arsenite, the toxic form of arsenic to humans, to arsenate. Arsenate (+5 oxidation state) is the dominant form of arsenic in surface water, while arsenite (+3 oxidation state) is the dominant form in hypoxic to anoxic environments. Arsenite is more soluble and mobile than arsenate. Many species of bacteria can transform arsenite to arsenate in anoxic conditions by using arsenite as an electron donor. This is a useful method in ground water remediation. Another bioremediation strategy is to use plants that accumulate arsenic in their tissues via phytoremediation but the disposal of contaminated plant material needs to be considered.
Bioremediation requires careful evaluation and design in accordance with existing conditions. Some sites may require the addition of an electron acceptor while others require microbe supplementation (bioaugmentation). Regardless of the method used, only constant monitoring can prevent future contamination. Arsenic removal. Coagulation and flocculation are closely related processes common in arsenate removal from water. Due to the net negative charge carried by arsenate ions, they settle slowly or not at all due to charge repulsion. In coagulation, a positively charged coagulent such as iron and aluminum (commonly used salts: FeCl3, Fe2(SO4)3, Al2(SO4)3) neutralize the negatively charged arsenate, enable it to settle. Flocculation follows where a flocculant bridges smaller particles and allows the aggregate to precipitate out from water. However, such methods may not be efficient on arsenite as As(III) exists in uncharged arsenious acid, H3AsO3, at near-neutral pH. The major drawbacks of coagulation and flocculation are the costly disposal of arsenate-concentrated sludge, and possible secondary contamination of environment. Moreover, coagulents such as iron may produce ion contamination that exceeds safety levels.
Toxicity and precautions. Arsenic and many of its compounds are especially potent poisons (e.g. arsine). Small amount of arsenic can be detected by pharmacopoial methods which includes reduction of arsenic to arsenious with help of zinc and can be confirmed with mercuric chloride paper. Classification. Elemental arsenic and arsenic sulfate and trioxide compounds are classified as "toxic" and "dangerous for the environment" in the European Union under directive 67/548/EEC. The International Agency for Research on Cancer (IARC) recognizes arsenic and inorganic arsenic compounds as group 1 carcinogens, and the EU lists arsenic trioxide, arsenic pentoxide, and arsenate salts as category 1 carcinogens. Arsenic is known to cause arsenicosis when present in drinking water, "the most common species being arsenate [; As(V)] and arsenite [; As(III)]". Legal limits, food, and drink. In the United States since 2006, the maximum concentration in drinking water allowed by the Environmental Protection Agency (EPA) is 10 ppb and the FDA set the same standard in 2005 for bottled water. The Department of Environmental Protection for New Jersey set a drinking water limit of 5 ppb in 2006. The IDLH (immediately dangerous to life and health) value for arsenic metal and inorganic arsenic compounds is 5 mg/m3 (5 ppb). The Occupational Safety and Health Administration has set the permissible exposure limit (PEL) to a time-weighted average (TWA) of 0.01 mg/m3 (0.01 ppb), and the National Institute for Occupational Safety and Health (NIOSH) has set the recommended exposure limit (REL) to a 15-minute constant exposure of 0.002 mg/m3 (0.002 ppb). The PEL for organic arsenic compounds is a TWA of 0.5 mg/m3. (0.5 ppb).