Tracing the Source of the Elephant And Hippopotamus Ivory from ...

local environment, and thus answer the question of how to measure biologically available
strontium isotope levels (Price et al. 2002: 122; see also Sillen et al. 1998).
Diagenesis (addition, loss, or replacement) of strontium in skeletal tissues is
another very important consideration however. Initially the problem was considered
dealt with if the samples were properly cleaned, as with acetic acid (Ericson 1985: 508),
or repeatedly washed in acetic acid/sodium acetate buffer solution (Sealy et al. 1991:
399). Other techniques for removing contamination are discussed in Price et al. (1992),
Sillen and Sealy (1995), Koch et al. (1997), and Nielsen-Marsh and Hedges (2000; cited
by Price et al. 2002: 127). Sealy et al. (1991, 1995) addressed problems of diagenesis of
strontium in bone, and concluded that while diagenesis definitely affects the elemental
abundance (Sr concentration), it does not seem to affect the isotopic ratio to any
considerable degree. However, more recent studies by Budd et al. (2000) and Chiaradia
et al. (2003) refute this. Moreover, treatments involving weak acids to remove diagenetic
material assume that the diagenetic Sr is additive and not exchanged (Budd et al. 2000:
668). Horn and Müller-Sohnius (1999) recently criticized Grupe et al. (1997) for not
recognizing signs of diagenesis in their data (increases in Sr content and changes in Sr
isotope ratio between enamel and bone) (discussed in Budd et al. 2000: 668; see also
Grupe’s reply: Grupe et al. 1999).
Budd et al. (2000) compared the Sr concentration and isotope ratios in enamel and
dentine from prehistoric, Romano-British and medieval individuals in Britain with soil
samples taken from each of the sites. They found that the Sr isotope ratios from the
enamel and soil samples were significantly different. The dentine Sr ratios were also
different from the soil, but closer in value. These results are not surprising if the
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