Whole blood and serum concentrations of metals in a Swedish population-based sample

Objective. While the potential toxicity of metals in humans is a well-established field of research, there are few studies that examine circulating concentrations of metals in large population-based samples. The aim of this study was to analyze levels of heavy metals and trace elements in both whole blood and serum in an elderly population, and to examine if gender, kidney function, haemoglobin or serum albumin could impact the distribution of metals between whole blood and serum. Methods. Whole blood and serum samples from 1016 70-year-olds living in Uppsala, Sweden, were analyzed for aluminium, cadmium, cobalt, copper, chromium, mercury, manganese, molybdenum, nickel, lead, and zinc using inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). Distribution between whole blood and serum was evaluated by the ratio between whole blood and serum concentration (B/S-ratio). Results. Concentrations differed significantly between whole blood and serum measurements for all 11 metals (p < 0.00001). The highest B/S-ratios were found for lead (27), zinc (9), manganese (6), and nickel (4). Copper (0.86), cobalt (0.84), and molybdenum (0.86) showed B/S-ratios < 1. Especially the B/S-ratios for chromium, mercury and nickel correlated with kidney function (GFR) (r = 0.21, - 0.21 and -0.36 respectively, p < 0.0001). Conclusions. The distribution between whole blood and serum varied considerably for different metals. This distribution correlated with physiological factors, mainly with kidney function, for several of the metals.