Examination of in vivo influences on bioluminescent microbial assessment of corrosion product toxicity

The composition of ionically dissolved and precipitated corrosion products from both free corrosion of ASTM F75 Co–Cr–Mo and galvanostatic polarization of Co–Cr–Mo and F138 316L stainless steel was determined using differential pulse polarography and inductively coupled plasma atomic emission spectroscopy. A bacterial bioluminescence assay, Microtox®, was used to assess the toxicity of the solid and dissolved corrosion products produced by galvanostatic polarization and the individual ions within them. The role of in vivo salinity, temperature, and protein content as modulators of corrosion product toxicity assessment was investigated empirically and mechanistically. Co–Cr–Mo products were found to be more toxic than those of 316L, and the most toxic ions were Cr6+, Ni2+, and Co2+. Ringerʹs solution potentiated the toxicity of the more toxic metal ions and reduced the toxicity of the less toxic ions. Using theoretical analysis in conjunction with experimental measurements, the ions in both alloys were found to interact in an antagonistic fashion. The presence of albumin was found to decrease metal toxicity, presumably by chelation.