The work carried out by Santé publique France to monitor lead exposure in the French population involves two approaches: biomonitoring studies such as Esteban (a health study on the environment, biosurveillance, physical activity, and nutrition) and the national surveillance system for blood lead levels (SNSPE).

The Esteban epidemiological study was conducted between 2014 and 2016. It determined lead exposure levels in the general French population aged 6 to 74 years, analyzed factors related to population exposure to lead, and tracked trends over time. The previous study to measure blood lead levels in the French population was the National Nutrition and Health Survey (ENNS), which was conducted among adults between 2006 and 2007. In the period between the ENNS and Esteban, the average blood lead level among adults (18–74 years) decreased from 27.5 µg/L to 18.5 µg/L.

The SNSPE, on the other hand, targets children aged 0 to 17 years who are at risk of overexposure to lead. These exposure situations may result from their home or living environment (e.g., lead paint), leisure activities (e.g., shooting sports (1)), or lifestyle and cultural practices (e.g., use of traditional remedies containing lead), but also from vocational training activities (e.g., apprenticeships in stained glass manufacturing or renovation). This surveillance system includes mandatory reporting of lead poisoning cases and covers children who have had at least one blood lead test.

The SNSPE therefore measures the incidence of lead poisoning in children considered at risk of overexposure, which is difficult to capture in biomonitoring studies such as the Esteban study.

The average blood lead level of children included in the SNSPE between 2015 and 2018 was 18.6 µg/L. This level was 9.9 µg/L for children aged 6 to 17 years, according to the Esteban study. As a point of reference, in its report of May 23, 2014, the High Council for Public Health (HCSP) (2) advocates a policy of reducing exposures to the lowest possible level in view of the non-threshold effects of lead. Its recommendations include a rapid intervention protocol for a blood lead level of 50 μg/L and a vigilance threshold at 25 µg/L. However, these levels do not correspond to a lead safety threshold, as this metal is a toxicant considered to have no threshold. Effects on the cognitive abilities of young children have been observed with blood lead levels below the vigilance threshold. It should be noted that these thresholds also apply to pregnant women.

The Esteban study showed that, despite a decrease in blood lead levels, exposure among the population was widespread. Lead was detected in all blood samples analyzed. The investigation into the determinants of exposure identified known risk factors (diet, tap water and alcohol consumption, tobacco use (cigarettes), age, sex, date of housing construction, parents’ occupational status (a risk factor for children), etc.). Esteban, for example, showed that children aged 6–10 years had higher lead levels than older children (11–17 years), and that girls had lower lead levels than boys. The study also confirmed the persistence of those lead exposure factors already known and described in the scientific literature, and made it possible to define Reference Exposure Values (REV) (3) for lead. These values serve as a reference for comparing blood lead levels measured in an individual or a subgroup of the French population. It is thus possible to identify individuals who are overexposed compared to the reference population. As an example, in 2019, post-fire monitoring of Notre-Dame Cathedral in Paris was established, and the blood lead levels of children screened around Notre-Dame were compared to those of children in the Esteban study (4).

Of the 2,511 new cases of lead poisoning reported in the SNSPE between 2015 and 2018, one-third were in French Guiana and nearly one-third were in Île-de-France. The Provence-Alpes-Côte d'Azur region accounted for nearly 16% of cases. The majority of cases were boys (52% of incident cases) with an average sex ratio (M/F) of 1.11. Children under 3 years of age accounted for 40% of lead poisoning cases, of which 45% were under 1 year of age.

The main environmental risk factors identified by physicians at the time of diagnosis were related to old and/or dilapidated housing, the presence of other poisoned children in their environment, and pica behavior.

Symptoms were infrequent among incident cases (8%) and mainly consisted of behavioral disorders such as irritability or agitation, sometimes associated with learning difficulties; digestive disorders such as abdominal pain and constipation; neurological signs (headaches, cerebellar ataxia, mental retardation); and autism-spectrum disorders. Since clinical signs are not very common and not very specific to lead poisoning, these results highlight the importance of identifying poisoned children by looking for environmental risk factors.

Lead exposure remains a public health problem in France. Continued efforts to raise awareness among healthcare professionals about the sources of lead exposure enable better identification of children at risk. The findings of the Esteban study and the SNSPE confirm the need to continue monitoring lead exposure and to continue documenting the associated risk factors. They demonstrate that public policy initiatives (replacement of lead pipes, lead testing in housing, lead-free gasoline, renovation of older housing, etc.) must be sustained. Recently, cases of lead poisoning related to metal recovery activities have been identified, requiring the implementation of specific prevention measures (5).

Given the toxicity of lead and its harmful effects on health, maintaining the lowest possible blood lead levels is a public health priority. The results of the national biomonitoring program are now used to inform public policy decisions aimed at continuing efforts to reduce lead exposure (e.g., regulations regarding the presence of lead in housing and drinking water pipes).

The Esteban study demonstrated widespread exposure to chemical substances in the French population using a substance-by-substance approach, enabling the identification of the determinants of exposure to a specific chemical. In the future, it will be important to examine multiple exposures to substances, which will allow for the assessment of actual exposure to a cocktail of chemicals. To verify the continued decline in levels among the general population and evaluate the persistence of risk factors, the next biomonitoring study should include blood lead level measurements, particularly in young children. It would also be appropriate to obtain, through collaboration with other health agencies, environmental data to combine with biomonitoring data in order to identify emerging sources of exposure.

The most vulnerable populations remain pregnant women and children, including young people in vocational training.