Graphite in various forms has become the standard target for accelerator 14C dating. Graphite has been made by catalytic graphitization of charcoals (Lowe,1984). Thin films of graphite have also been produced by thermal cracking (Beukens & Lee, 1981), electric discharge (Andree et al, 1984;Wand, Gillespie & Hedges, 1984). Vogel et al (1984) pointed out the ease of graphite formation on iron from CO2 and H2 mixtures at ca 600°C. The deposition reactions of carbon from the CO, H2, and CO2 equilibria are well known (Wagman et al, 1945) and well studied. Formation of graphite from CO2 was discussed extensively by Boudouard (1902) and Schenck and Zimmerman (1903), and was known to chemists in France in 1851. We have used a related method, where graphite forms away from the iron, by using a higher temperature, and reduction of CO2 to CO over Zn in the presence of H2 (,Dull et al, 1986) as an alternative to the use of Fe alone. The object of this paper is to point out an even simpler graphite preparation system, which eliminates hydrogen. The decomposition reaction of CO (Boudouard, 1902) takes place according to reaction (1). 2C0CO2 + C (gr) (1) If carbon is introduced as C02, and is reduced to CO by hot Zn and any C02 formed due to reaction (1) is reduced to CO by the hot Zn, then the reaction proceeds in one direction. This method uses a small-volume system, which can be of any size but is typically 5 to 10cc. Using a 5cc system, reduction of CO samples of as small as 0.7cc has been achieved. The apparatus is shown in Figure 1. As mentioned, two reactions occur in the system. CO2 is reduced to CO over -30mg Zn at ca 500°C, and the CO disproportionates to graphite over the iron (1 mg) mg) at typically 700°C. Deposition occurs at temperatures as low as 450°C. The graphite is separate from the iron, suggesting a vapor-phase intermediate.The gas pressure is monitored, and 100% reaction is easily observable, as we wait until the gas pressure is zero. This takes from 2 to 10 hours, depending on several factors. It is clear that the reaction is pressure-and temperature-dependent; however, variations in reaction rate appear to be complex, and apparently dependent on the catalyst. The amount of Fe catalyst used can be very small (< 1 mg) without measurable effect on the reac-

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The study covered the children living in Miasteczko Slaskie, near the largest Zn plant in Poland. This is one of the areas highly contaminated with heavy metals. The subjects were 158 children aged from 8 to 15 (98 boys and 60 girls). The average Pb and Cd levels in the hair of the entire children population was 8.21 +/- 5.59 microg/g, and 0.91 +/- 0.61 microg/g, and the average Pb and Cd levels in their blood were 14.32 +/- 3.98 and 0.52 +/- 0.24 microg/dL(-1), respectively. The children population under investigation was divided according to their sex. The hair of the girls contained, on the average, 5.06 +/- 2.81 microg/g of Pb and 0.74 +/- 0.48 microg/g of Cd and the hair of the boys 10.14 +/- 6.0 microg/g of Pb and 1.01 +/- 0.65 microg/g of Cd. The blood of the girls contained, on the average, 13.23 +/- 4.23 microg/dL of Pb and 0.48 +/- 0.21 microg/dL of Cd, and the blood of the boys 14.99 +/- 3.68 microg/dL of Pb and 0.55 +/- 0.24 microg/dL of Cd. Thus, both the hair and blood of the boys accumulated more Pb and Cd than those of the girls. A correlation between the concentrations of these metals was confirmed.

The radiocarbon (14C) method is a well-known isotopic dating technique by which age can be assigned to organic materials, including human bone. Natural and anthropogenic anomalies in 14C activity in the biosphere over the last few centuries, including the presence of artificial or “bomb” 14C after 1950, can be used as an isotopic tracer to assign human bone samples with high degrees of probability to one of three temporal periods within the recent past: a Non-modern period (before about A.D. 1650) of no forensic science interest, a Pre-modern period (A.D. 1650 to 1950) of possible or potential forensic science interest, and a Modern period (A.D. 1950 to the present) of definite forensic science interest. We illustrate the use of the 14C method to assign human bone in five forensic science cases to one of these time periods.

Radiocarbon analyses by accelerator mass spectrometric (AMS) techniques on organic fractions of human bone from various North American localities previously assigned ages ranging from about 70,000 to 15,000 years B.P. now suggest that none of these skeletons is older than 11,000 C-14 years B.P.