Risk factors and early renal effects of environmental exposure to the trace elements in Moroccan adolescents

BACKGROUND In Morocco, the use of leaded-gasoline is still common even after its ban in 2011, and other sources of contamination by traces elements are not regulated. We aimed to assess blood and urinary cadmium, blood lead, and total blood mercury levels in Moroccan adolescents and to identify determinants and early renal effects of exposure. METHODS The study included 149 school adolescents (12 to 18 years), from urban, industrial, and rural areas in Fez city (north of Morocco). Risk factors were investigated by interviews and questionnaires. Internal doses and early renal effects were evaluated by analyzing blood and urinary samples. RESULTS The mean of blood lead levels (BLLs) in all adolescents was 47.81μg/l with no difference between boys and girls. Adolescents from the urban area had the highest BLLs mean. The means of blood cadmium levels (BCLs) and urinary cadmium levels (UCLs) were 0.29μg/l and 0.45μg/l respectively, with no differences between living areas or according to sex. The total blood mercury levels (BMLs) mean was 0.52 μg/l. BMLs mean was higher in the industrial area and among boys. This can be associated to the frequency of fish intake, the use of dental amalgams fillings, and the consumption of chewing gum. Rates of early renal effects markers were low, not correlated to the metals, and may indicate that renal effects of this environmental exposure could be limited. CONCLUSIONS There is an urgent need for the limitation of trace elements' sources, particularly the strict application of the laws concerning leaded-petrol prohibition.