Synchrotron-based techniques for studying the environmental health effects of heavy metals: Current status and future perspectives

This review summarizes the state-of-the-art synchrotron-based techniques for studying the environmental health effects of heavy metals exposure. Synchrotron radiation based X-ray fluorescence (SRXRF) is widely applied in quantification of metals in different biological and environmental samples. X-ray absorption spectrometry (XAS) is used for speciation of heavy metals. With high energy resolution fluorescence detected (HERFD) XAS, it is possible to study heavy metals in biological samples at realistic concentrations. The focused synchrotron-based X-ray is applied to image metals down to nm resolution at 2- or 3- dimension (2D or 3D). The combination of XAS with SRXRF can realize 2D or 3D spatial speciation, along with other techniques like scanning transmission X-ray microscopy (STXM) and full field XAS. The structure of metal-binding biomolecules can be characterized by Protein X-ray Diffraction (PX) and/or XAS, together with neutron scattering. The future aspects of multimode detection, new imaging methods, fast detector technologies and big data strategies in synchrotron-based techniques were also discussed.