Clair Cameron Patterson 239630 224539464 2008-07-09T09:04:50Z 132.244.246.25 Improved formatting of infobox {{Infobox Scientist |name = Clair Cameron Patterson |image = Replace_this_image_male.svg |caption = Clair Cameron Patterson |birth_date = [[June 2]], [[1922]] |birth_place = [[Mitchellville, Iowa]] |death_date = [[December 5]], [[1995]] |death_place = |residence = |citizenship = |nationality = [[United States]] |ethnicity = |field = [[geochemistry]] |work_institutions = |alma_mater = [[Grinnell College]] |doctoral_advisor = |doctoral_students = |known_for = [[uranium-lead dating]] |author_abbrev_bot = |author_abbrev_zoo = |influences = |influenced = |prizes = [[Tyler Prize]] for Environmental Achievement, 1995, Goldschmidt Medal of the Geochemical Society in 1980, and the [[J. Lawrence Smith Medal]] of the National Academy of Sciences in 1973 |religion = |footnotes = |signature = }} '''Clair Cameron Patterson''' ([[June 2]], [[1922]] – [[December 5]], [[1995]]) was a [[geochemist]] born in Mitchellville, [[Iowa]], [[United States]]. He graduated from [[Grinnell College]] in Grinnell, Iowa. Patterson developed the [[uranium-lead dating]] method into [[lead-lead dating]], and by using [[lead]] [[Isotope|isotopic]] data from the [[Canyon Diablo]] [[meteorite]], he calculated an [[Age of the Earth|age for the Earth]] of 4.55 billion years; a figure far more accurate than those that existed at the time and one that has remained unchanged for over 50 years. Patterson had first encountered lead contamination in the late 1940s as a graduate student at the [[University of Chicago]]. His work on this led to a total re-evaluation of the growth in lead concentrations in the atmosphere and the human body from industrial causes and his subsequent campaigning was seminal in the banning of lead additives to gasoline and lead solder in food cans. ==Early Life== Clair (Pat) Patterson was born in [[Mitchellville, Iowa]] and graduated from [[Grinnell College]] in chemistry where he met his wife, Lorna (Laurie) McCleary. They both moved to the [[University of Iowa]] for graduate work where he did an M.A. in molecular [[spectroscopy]]. Both were then sent to work on the [[Manhattan Project]], first at the University of Chicago and then at [[Oak Ridge, Tennessee]] where he encountered [[mass spectrometry]].<ref>[http://books.nap.edu/openbook.php?record_id=6201&page=267 Biographical memoir by George R. Tilton]</ref> After the war they returned to Chicago where Laurie took a research job as a infrared spectroscopist to support Pat whilst he did a Ph.D. at the University of Chicago under Harrison Brown. He and Laurie had four children. == Estimate of the Earth's age == [[Harrison Brown]] of the University of Chicago developed a new method for counting lead isotopes in [[igneous]] rocks, and assigned it to Patterson as a dissertation project in 1948. During this period he operated under the assumption that [[meteorites]] are left-over materials from the creation of the [[Solar System]], and thus by measuring the age of one of these rocks the age of the Earth would be revealed. Gathering the materials required time, and in 1953, Patterson had his final specimens from the [[Canyon Diablo meteorite]]. He took them to the [[Argonne National Laboratory]], where he was granted time on a late model [[mass spectrograph]]. Purportedly, he was so excited with the results that he drove home to Iowa and had his mother check him into hospital as a precaution, since he thought he was having a [[myocardial infarction|heart attack]]. In a meeting in Wisconsin soon afterward, Patterson revealed the results of his study. The definitive [[age of the Earth]] is 4.550 billion years (give or take 70 million years). This number still stands. == Tracing the Geochemical evolution of the Earth == His ability to isolate microgram quantities of lead from ordinary rocks and determine their isotope composition led him to examining the lead in ocean sediment samples from the Atlantic and Pacific. Deriving from the different ages at which the landmasses had drained into the ocean, he was able to show that the amount of anthropogenic lead presently dispersed into the environment was about eighty times the amount being deposited in the ocean sediments: the geochemical cycle for lead appeared to be badly out of balance. The limitations of the analytic procedures led to him using other approaches. He found that deep ocean water contained 3-10 times less lead than surface water, in contrast to similar metals such as barium. This led him to doubt the commonly held view that lead concentrations had only grown by a factor of two over naturally occurring levels. Patterson returned to the problem of his initial experiment and the contamination he had found in the blanks used for sampling. He determined through ice-core samples from Greenland that atmospheric lead levels had begun to increase steadily and dangerously soon after [[tetra-ethyl lead]] began to see widespread use in fuel, when it was discovered to reduce engine "knock" in [[internal combustion engines]]. Patterson subsequently identified this, along with the various other uses of lead in manufacturing, as the cause of the contamination of his samples, and because of the significant public-health implications of his findings, he devoted the rest of his life to removing as much introduced lead from the environment as possible. == Campaign against lead poisoning == Beginning in 1965, with the publication of ''Contaminated and Natural Lead Environments of Man'', Patterson tried to draw public attention to the problem of increased lead levels in the environment and the food chain due to lead from industrial sources. Perhaps partly because he was criticizing the experimental methods of other scientists, he encountered strong opposition from recognized experts such as [[Robert A. Kehoe]]. In this effort, he fought against the lobbying power of the [[Ethyl Corporation]], which Kehoe worked for, with all its influence (and the legacy of [[Thomas Midgley]], which included tetra-ethyl lead and [[chlorofluorocarbon]]s) and the lead additive industry as a whole, to ensure that lead was removed from gasoline (petroleum). In ''[[A Short History of Nearly Everything]]'', author [[Bill Bryson]] notes that following his criticism of the lead industry he was refused contracts with many research organisations, including the supposedly neutral United States Public Health Service, and was excluded from a 1971 [[United States National Research Council|National Research Council]] panel on atmospheric lead contamination. Patterson's efforts ultimately led to the [[United States Environmental Protection Agency|Environmental Protection Agency]] announcing in 1973 a reduction of 60-65% in phased steps, and ultimately the removal of lead from all gasoline in the United States by 1986. Lead levels within the blood of Americans are reported to have dropped by up to 80% by the late 1990s.<ref>{{cite web | title = Blood Lead Levels Keep Dropping; New Guidelines Proposed for Those Most Vulnerable | date = 1997-02-20 | accessdate = 2007-07-31 | url = http://www.hhs.gov/news/press/1997pres/970220.html }}</ref> He then turned his attention to lead in food where similar experimental deficiencies had masked the increase. In one study he showed an increase in lead levels from 0.3 to 1400 nanograms per gram in certain canned fish compared with fresh, whilst the official laboratory had reported an increase of 400 to 700<ref>D. M. Settle and C. C. Patterson. Lead in albacore: guide to lead pollution in Americans. Science 207(1980):1167-76</ref>. He compared the lead, barium and calcium levels in 1600 year-old Peruvian skeletons and showed a 700 to 1200 fold increase in lead levels in modern human bones with no comparable changes in the others<ref>J. E. Ericson, H. Shirahata, and C. C. Patterson. Skeletal concentrations of lead in ancient Peruvians, N. Engl. J. Med. 300(1975):949-51.</ref>. In 1978 he was appointed to an NRC panel which accepted many of the increases and the need for reductions but argued the need for more research<ref> Lead in the Human Environment. Washington, D.C.: National Academy of Sciences, 1980.</ref>. His opinions were expressed in a 78-page minority report which argued that control measures should start immediately, including gasoline, food containers, paint, glazes and water distribution systems. Thirty years later, most of these have been accepted and implemented the United States and many other parts of the world. ==Further reading== *Patterson, C. (1956) "Age of meteorites and the Earth" Geochimica et Cosmochimica Acta 10, 230-237 *Patterson, C, Chow, T. J. (1962) "The occurrence and significance of lead isotopes in pelagic sediments". Geochim. Cosmochim. Acta 26:263-308 *Patterson, C. (1965) "Contaminated and natural environments of man" Arch. Environ. Health 11, 344-360 *Bryson, B. (2003) "A Short History of Nearly Everything", 193-255 *"Lead-Free Gasoline and Clair C. Patterson" Chapter 9 in S. Bertsch McGrayne "Prometheans in the Lab" McGraw-Hill: New York, 2002. ISBN 0-07-140795-2 *[http://www.nap.edu/html/biomems/cpatterson.html Clair Cameron Patterson by George R. Tilton] ==References== <references/> *{{Citation |id = [[PMID]]:10943366 |url= http://www.ncbi.nlm.nih.gov/pubmed/10943366 |last=Casanova |first=I |publication-date=1998 Sep |year=[[1998]] |title=Clair C. Patterson (1922-1995), discoverer of the age of the Earth. |volume=1 |issue=3 |periodical=Int. Microbiol. |pages=231-2 }} *{{Citation |id = [[PMID]]:9725987 |url= http://www.ncbi.nlm.nih.gov/pubmed/9725987 |last=Flegal |first=A R |publication-date=1998 Aug |year=[[1998]] |title=Clair Patterson's influence on environmental research. |volume=78 |issue=2 |periodical=Environ. Res. |pages=64-70 }} *{{Citation |id = [[PMID]]:9719611 |url= http://www.ncbi.nlm.nih.gov/pubmed/9719611 |last=Needleman |first=H L |publication-date=1998 Aug |year=[[1998]] |title=Clair Patterson and Robert Kehoe: two views of lead toxicity. |volume=78 |issue=2 |periodical=Environ. Res. |pages=79-85 |doi = 10.1006/enrs.1997.3807 }} *{{Citation |id = [[PMID]]:9719609 |url= http://www.ncbi.nlm.nih.gov/pubmed/9719609 |publication-date=1998 Aug |year=[[1998]] |title=Clair Patterson's Influence on Environmental Research. |volume=78 |issue=2 |periodical=Environ. Res. |pages=65-185 }} *{{Citation |id = [[PMID]]:9719610 |url= http://www.ncbi.nlm.nih.gov/pubmed/9719610 |last=Nriagu |first=J O |publication-date=1998 Aug |year=[[1998]] |title=Clair Patterson and Robert Kehoe's paradigm of "show me the data" on environmental lead poisoning. |volume=78 |issue=2 |periodical=Environ. Res. |pages=71-8 |doi = 10.1006/enrs.1997.3808 }} {{DEFAULTSORT:Patterson, Clair}} [[Category:1922 births]] [[Category:1995 deaths]] [[Category:Grinnell College people]] [[Category:American chemists]] [[Category:Geochemists]] [[Category:People from Iowa]] [[de:Clair Cameron Patterson]] [[es:Clair Cameron Patterson]] [[hr:Clair Cameron Patterson]] [[it:Clair Patterson]] [[nl:Clair Patterson]]