Comparative study of 14 metal exposure biomarkers in biological samples

Background  Due to the differences in the distribution and metabolism characteristics of metals in human body, the metal concentrations in different biological samples are quite different, and environmental health research results may be easily affected by the selected biological samples.

Objective  This study aims to systematically evaluate the priority of various metal biomarkers in environmental health research.

Methods  We searched PubMed database for 26 073 and 12948 studies on internal and external exposure to toxic metals (aluminum, arsenic, cadmium, chromium, mercury, nickel, lead, and antimony) and essential elements (cobalt, copper, iron, manganese, vanadium, and zinc) in eight groups of biological samples (whole blood, blood/red blood cells, serum, plasma, urine, hair, fingernail/toenail, and saliva) published from the establishment of the database to March 13, 2021. After screening, 295 and 105 studies were included. The evaluation indexes were extracted and summarized. According to the method of superiority chart, the weight coefficients of evaluation indexes were determined, weighted optimum order numbers of the selected exposure biomarkers were calculated, and the exposure biomarkers were ranked by the weighted optimum order numbers.

Results  The highest weighted optimum order numbers were chromium (0.872), lead (1.000), cobalt (0.863), and vanadium (0.815) in whole blood, manganese (0.816) in blood/red blood cells, aluminum (0.866), arsenic (0.833), cadmium (0.851), mercury (0.828), nickel (0.915), and zinc (0.823) in urine, antimony (0.841) and iron (1.000) in hair, and copper (0.776) in fingernail/toenail when compared with other groups of biological samples.

Conclusion  In environmental health research, whole blood may be suitable for determining concentrations of chromium, lead, cobalt and vanadium, blood/red blood cells for determining concentrations of manganese, urine for determining concentrations of aluminum, arsenic, cadmium, mercury, nickel and zinc, hair for determining concentrations of antimony and iron, and fingernail/toenail for determining concentrations of copper.