The effects of Paraloid B-72 and Butvar B-98 treatment and organic solvent removal on [delta]13C, [delta]15N, and [delta]18O values of collagen and hydroxyapatite in a modern bone

Stable isotopes in bones are a powerful tool for diet, provenance, climate, and physiological reconstructions, but necessarily require well-preserved specimens unaltered by postmortem diagenesis or conservation practices. This study examines the effects of Paraloid B-72 and Butvar B-98, two common consolidants used in field and museum conservation, on [delta]13C, [delta]15N, and [delta]18O values from bone collagen and hydroxyapatite. The effects of solvent removal (100% acetone, 100% ethanol, 9:1 acetone:xylenes, 9:1 ethanol:xylenes) and drying methods (ambient air, vacuum, oven drying at 80°C) were also examined to determine if bones treated with these consolidants can successfully be cleaned and used for stable isotope analyses. Results show that introduction of Paraloid B-72 or Butvar B-98 in 100% acetone or 100% ethanol, respectively, with subsequent removal by the same solvents and drying at 80°C facilitates the most successful removal of consolidants and solvents. The [delta]13C values in collagen, [delta]15N in collagen, [delta]18O in hydroxyapatite phosphate, and [delta]13C in hydroxyapatite structural carbonate were unaltered by treatments with Paraloid or Butvar and subsequent solvent removal. The [delta]18O in hydroxyapatite structural carbonate showed nonsystematic variability when bones were treated with Paraloid and Butvar, which is hypothesized to be a result of hydroxyl exchange when bones are exposed to consolidants in solution. It is therefore recommended that [delta]18O in hydroxyapatite structural carbonate should not be used in stable isotope studies if bones have been treated with Paraloid or Butvar. Am J Phys Anthropol 157:330-338, 2015. © 2015 Wiley Periodicals, Inc.