The effects of Paraloid B-72 and Butvar B-98 treatment and organic solvent removal on δ13C, δ15N, and δ18O values of collagen and hydroxyapatite in a modern bone

ABSTRACT 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 δ13C, δ15N, and δ18O 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 δ13C values in collagen, δ15N in collagen, δ18O in hydroxyapatite phosphate, and δ13C in hydroxyapatite structural carbonate were unaltered by treatments with Paraloid or Butvar and subsequent solvent removal. The δ18O 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 δ18O 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.