Chapter 3E: Lead

Lead can be released into the atmosphere from natural and anthropogenic sources. Significant reduction of emission, by more than 90%, took place in European countries between 1990 and 2003.

Most of the information on human exposure to lead and the health effects related to it is based on the lead in blood (B-Pb) levels, which are considered to be the biomarker of choice. A major advantage of this measure is the wealth of information that can be linked to B-Pb, particularly the effects of low environmental exposure on central nervous system functions in children, who are considered to form the critical population.

There is no evidence of a threshold below which lead does not cause neurodevelopmental toxicity in children, and at present no particular B-Pb cutoff can be defended. Establishing a level of concern lower than the present 100 μg/L may provide a false sense of safety about the well-being of children whose B-Pb levels are below this value.

Therefore, it seems that, as in the case of other substances which lack a well-defined threshold of toxic effects, the lead-related risk assessment can be performed on the basis of a kind of “unit risk”. In 2010, the EFSA CONTAM Panel proposed the BMDL₀₁ of 12 μg/L B-Pb, defined as the increase of the B-Pb level which induces the loss of 1 IQ point. This value can be used to calculate the possible decrease of IQ and, consequently, the influence of low-level exposure to lead on the health and socioeconomic status of the exposed population.