Background: Knowledge of time trends in burdens of the heavy metals cadmium (Cd), lead (Pb) and mercury (Hg) are important to evaluate effects of preventive actions. This has previously been monitored in northern Sweden in samples from 1990-1999. Alpha-1-microglobuline (A1M) in urine is a potential biomarker of tubular dysfunction, presumed to be effected by body burdens of cadmium. It is unknown if elements from catalytic converters, platinum (Pt), rhodium (Rh) and palladium (Pd), cause human exposure.

Objective: To continue the time trend series of body burdens of Cd, Pb and Hg and to quantify levels of Pt, Rh and Pd and alpha-1-microglobuline in samples from northern Sweden.

Design: Biobanked blood samples from health screenings in the WHO MONICA-project in northern Sweden were analyzed for Cd, Pb and Hg, in two age-groups; 25-35 years and 50-60 years. In 2004, blood samples from 287 women were analysed and in 2009, blood samples from 150 men and 177 women were analyzed. Also, cadmium and A1M were analysed in urine for the 2004 and 2009 participants. Pt, Rh and Pd were analysed in blood for 26 women in ages 55-59 years from the 2009 screening.

Results: There was a decline in blood levels of Pb in both men and women. Blood levels of Cd did not change over time. However, in women, levels of U-Cd were lower in 2009 as compared to 2004, also in never-smokers in the younger age-group. Due to use of erythrocytes in the previous report on data from 1990-99, body burdens of Hg could not be compared to previous data. A decrease from 2004 to 2009 was detected in B-Hg in women in the older age-group. Levels of Pd could not be quantified due to high uncertainty in the analysis. Blood levels of Pt and Rh were at levels of about one thousandth of the heavy metals. Levels of protein A1M in urine could not be compared over time, due to changes in analytical method. Levels of the protein were higher in the older age-group and men had higher levels than women in samples from 2009.

Conclusion: The previously detected decline in body burdens of Pb continued from 1999 to 2009, while there is still no evident change in body burdens of Cd. We cannot evaluate the time trend of Hg body burdens after 1999 with these data. Levels of Pt and Rh are detectable. Surprisingly, men in the older age-group had higher levels than women of protein A1M. For Cd, there are indications of risk of adverse health effects at the reported levels. Efforts to reduce pollution and human exposure to all three heavy metals are important, but this is especially important for cadmium.