Comment on: metals in bones of the middle-aged inhabitants of Sardinia island (Italy) to assess nutrition and environmental exposure [Bocca et al. (2018), Environ Sci Pollut Res]

This comment addresses several inferences made by Bocca et al. (2018) to assess the nutrition of middle-aged inhabitants from four Sardinian localities (Alghero, Bisarcio, Geridu, and Sassari). Bocca et al. analyzed 72 human bone specimens dating from the twelfth to the eighteenth century for metal contents (Ba, Ca, Cd, Cu, Hg, Pb, Sr, and Zn) by SC-ICP-MS and applied a univariate and multivariate approach, using element-Ca ratios, to examine the eating habits and environmental exposure of the individuals. While we agree with their interpretation of the Hg/Ca and Pb/Ca ratios, attributable to various forms of environmental exposure, we disagree with some of their paleodiet claims.