Interview with Clair C. Patterson

In this interview in March 1995, nine months before his death, Clair C. (Pat) Patterson, professor of geochemistry, emeritus, talks about his early interest in physical chemistry; his education at Grinnell College, in Iowa; his stint on the Manhattan Project at Oak Ridge; and his subsequent graduate work at the University of Chicago with Harrison Brown, where he measured the isotopic composition and concentration of minute quantities of lead with a mass spectrometer. He received his PhD at Chicago in 1951. After a year there as a postdoc, he came to Caltech with Brown, who established a geochemistry program in the Division of Geology. By 1953, having measured the isotopic composition of primordial lead in iron meteorites, Patterson was able to determine the age of the earth at 4.5 billion years. He then turned to a study of the natural levels of terrestrial lead and discovered that in the modern industrial environment, lead concentrations had greatly increased, from such sources as leaded gasoline and the solder used in food cans--with a corresponding increase in lead levels in human beings. He discusses his investigation of lead levels in seawater, oceanic sediments, and polar ice cores and his calculation of the rise in environmental lead levels beginning with the mining of lead in Greek and Roman times. At the end of the interview, he discusses his current interest in the evolution of different neuronal networks for two kinds of thinking, utilitarian and nonutilitarian--and his belief that this is illustrated by similarities in utilitarian thinking in the Old and New Worlds, while their cultural (nonutilitarian) development was dissimilar

Magnitudes and sources of precipitation and dry deposition fluxes of indestrial and natural leads to the North Pacific at Enewetak

A total atmospheric Pb input flux of 7 ng Pb cm^−2 yr^−1 was measured in the North Pacific Easterlies at Enewetak. Parameters used to measure this flux were ratio of dry deposition flux to precipitation flux; Pb/^(210)Pb in precipitation and seawater; ^(210)Pb flux; washout factor; and Pb concentrations in air, rain, and dry deposition deposits. Relations among these parameters established at Enewetak were used to recompute and confirm previous estimates of lead fluxes to the oceans (ng Pb cm^−2 yr^−1) at the following locations: North Atlantic Westerlies, 170; North Pacific Westerlies, 50; and South Pacific Easterlies, 3. Prehistoric lead output fluxes to sediments (ng Pb cm^−2 yr^−1) at these locations have been previously measured and were 4 (Enewetak); 30 North Atlantic Westerlies; 3 North Pacific Westerlies; 4 South Pacific Easterlies. These data show that the rates of atmospheric inputs of lead to the oceans vary directly with variations in rates of upwind emissions of industrial lead from urban complexes on land. In the North Pacific and North Atlantic, present rates of atmospheric lead inputs are 10-fold greater than prehistoric outputs. In equatorial regions, present inputs and past outputs are more nearly equal. These observations disclose the effects of intense industrial atmospheric emissions of lead in the northern hemisphere westerlies which have overwhelmed prehistoric natural fluxes of lead to the oceans. The average concentration of lead in marine air at Enewetak is 170 pg m−3 and varies less than a factor of 2 from that mean. One to 15% of this lead comes from seaspray, while the remainder comes from sources on land. About 90% of the seaspray lead is industrial, while 80 to 99% of that originating from land sources is industrial. Concentrations of lead in rain at Enewetak range from 6 to 63 pg/g with a mean value of 28. The mean precipitation flux, corrected for recycled lead in sea salts, measured by four different methods, was 6 ng Pb cm^−2 yr^−1, while the net dry deposition flux measured on horizontal plastic plates was 0.6 ng Pb cm^−2 yr^−1. The total dry deposition flux measured was 6 ng cm^−2 yr^−1, but 90% of this lead came from recycled seaspray. Lead isotope tracers show that Japan is the major source of industrial lead at Enewetak during the dry season, while the United States is the major source during the wet season

Relative levels of natural and anthropogenic lead in recent Antarctic snow

Concentrations of lead have been measured by ultraclean isotope dilution mass spectrometry in large blocks of surface snow collected along a 433-km coast-interior axis in East Antarctica and near the geographic south pole. Slight contamination existed on the outside of the blocks, but concentration profiles from their exteriors to their interiors indicate that lead concentrations in the innermost parts of the blocks do represent the original concentrations in present-day Antarctic snow. Geographical variations of lead concentrations appear to be mainly due to local emissions from Dumont d'Urville and Amundsen Scott stations. The globally significant lead concentration in present-day Antarctic snow is found to be about 2 pg Pb/g. The corresponding value in Antarctic air is estimated to be about 7 pg Pb/m^3 STP, which is approximately fivefold larger than total natural lead contributed by soil dusts, volcanoes and sea salts. A tentative temporal curve of globally significant lead concentrations in Antarctic ice and snow for the last 13,000 years is given. It shows concentrations of about 0.4 pg Pb/g throughout most of the Holocene, with recent fivefold increases to about 2 pg Pb/g today. The general picture is then that four-fifths of total lead in the Antarctic troposphere today is anthropogenic

Detection of Trace Amounts of Toxic Metals in Environmental Samples by Laser-excited Atomic Fluorescence Spectrometry

Results for the direct determination of trace amounts of Pb and Cd in Antarctic and Greenland ancient ice and recent snow by laser-excited atomic fluorescence spectrometry (LEAFS) are presented. The whole procedure starting from field sampling, mechanical decontamination of the samples in an ultra-clean laboratory and final analysis of the decontaminated samples is described. The measured concentrations varied in the ranges 0.1–3 pg ml^(–1) for Cd and 0.3–30 pg ml^(–1) for Pb. The results for direct analysis by LEAFS agree favourable with those obtained by isotope dilution mass spectrometry and electrothermal atomic absorption spectrometry, which require time-consuming pre-treatment and pre-concentration stages

The distribution of lead between sea salt dust, and lead-rich aerosols in the mid South Pacific easterlies at American Samoa

Aerosols in the South Pacific Easterlies have been sampled at American Samoa with a cascade impactor and analysed for Pb, Ba, K, Ca, Sr, and Rb by isotope dilution mass spectrometry using ultraclean procedures. Some 84% of the Pb was found in fine (≤ 0.5 μm) aerosols which were collected on the backup filter with an efficiency of only 33%. Sea salt and eroded terrestrial material (dust) containing 6% and <1% respectively, of the Pb (sea salt indexed by the metals K, Ca, Sr, and Rb and dust indexed by Ba) were collected on early stages of the impactor, although 65% of the dust, because of its larger size, was lost to surfaces of the rain shelter before reaching the impactor. The remaining 10% of the Pb was associated with plant leaf waxes of continental origin which produced Pb and Ba peaks on stage 4 (0.5 μ) of the impactor

Exile

Byron rehearsed going into exile in 1809, when he was twenty-one years old. Before setting sail for Lisbon, he wrote, “I leave England without regret, I shall return to it without pleasure. – I am like Adam the first convict sentenced to transportation, but I have no Eve, and have eaten no apple but what was sour as a crab and thus ends my first Chapter” (BLJ 1: 211). Byron’s sardonic perception of himself as a biblical exile foreshadowed the allusive character of his second longer-term exile at the age of twenty-eight, when his carefully staged exit required an audience (some of the same friends and servants), expensive props (a replica of Napoleon’s carriage) and a literary precursor. On his last evening in England, Byron visited the burial place of the satirist Charles Churchill, and lay down on his grave. It was a performance of immense weariness with life and solidarity with an embittered outcast.Postprin