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Lead (82 Pb) has four observationally stable isotopes: 204 Pb, 206 Pb, 207 Pb, 208 Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide.The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains: the uranium series (or radium series), the actinium series, and the thorium series, respectively; a fourth decay chain, the neptunium series ...
The U/Pb ratio was so low that no radiogenic decay was detected in the isotopic composition. [3] As illustrated in figure 1, this point defines the lower (left) end of the isochron. Therefore, troilite found in Canyon Diablo represents the primeval lead isotope composition of the solar system, dating back to 4.55 ± 0.07 Byr.
Lead is perhaps the best example of a partly radiogenic substance, as all four of its stable isotopes (204 Pb, 206 Pb, 207 Pb, and 208 Pb) are present primordially, in known and fixed ratios. However, 204 Pb is only present primordially, while the other three isotopes may also occur as radiogenic decay products of uranium and thorium.
The US Food and Drug Administration has proposed setting lead levels in baby food of 10 parts per billion for many products and 20 parts per billion for cereals and root vegetables, which can ...
2. Baby Food. One might think that a product advertised for infants and young children would be safe to eat. Alas, it's shocking how much food marketed to kids contains lead.
In forensic science, research suggests that the variation in certain isotope ratios in drugs derived from plant sources (cannabis, cocaine) can be used to determine the drug's continent of origin. [15] In food science, stable isotope ratio analysis has been used to determine the composition of beer, [16] shoyu sauce [17] and dog food. [18]
The FDA guidance caps lead levels for children younger than 2 at 10 parts per billion for fruits, most vegetables, grain and meat mixtures, yogurts, custards and puddings, and single-ingredient meats.
An isotopic signature (also isotopic fingerprint) is a ratio of non-radiogenic 'stable isotopes', stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry against an isotopic reference material.