Santé publique France is tasked with monitoring lead exposure among the population living in France through two approaches: biomonitoring studies such as Esteban (Study on Health, the Environment, Biomonitoring, Physical Activity, and Nutrition), and the National System for Monitoring Lead Levels in Children (SNSPE).

The Esteban epidemiological study conducted in 2014–2016 determined lead exposure levels in the general French population aged 6 to 74, analyzed the determinants of lead exposure, and tracked trends over time. The previous study to measure blood lead levels (concentration of lead in the blood) among French adults was the ENNS (National Nutrition and Health Study) conducted in 2006–2007. Between ENNS and Esteban, the average blood lead level among adults (ages 18–74) decreased from 27.5 µg/L to 18.5 µg/L.

The SNSPE, meanwhile, targets children aged 0 to 17 inclusive who are at risk of overexposure to lead. These exposure situations may result from their housing or living environment (e.g., lead-based paint), their leisure activities [e.g., sport shooting] (1), or lifestyle habits and practices (e.g., use of traditional remedies containing lead), as well as vocational training activities (e.g., apprentices in stained-glass manufacturing or restoration). This surveillance system includes mandatory reporting (MR) of lead poisoning cases and covers children who have undergone at least one blood lead level test.

The SNSPE therefore measures the incidence of lead poisoning among children considered at risk of overexposure who are difficult to capture in biomonitoring studies such as Esteban.

The average blood lead level among children in the SNSPE between 2015 and 2018 was 18.6 µg/L. This level was 9.9 µg/L among children aged 6 to 17, according to the Esteban study. For information, in its report of May 23, 2014, the High Council for Public Health (HCSP) (2) advocates a policy of reducing exposure to the lowest possible level to account for the no-threshold effects of lead and recommends a rapid intervention level starting at a blood lead level of 50 μg/L and a vigilance threshold at 25 μg/L. However, these thresholds do not correspond to a safety threshold for lead, as this metal is a toxin considered to have no safe level. Effects on the cognitive abilities of young children have been observed even at blood lead levels below the vigilance threshold. It should be noted that these management thresholds also apply to pregnant women.

The Esteban study demonstrated that, despite a decline in blood lead levels, exposure among the population is widespread. Lead was detected in all blood samples analyzed. The investigation into the determinants of exposure revealed known exposure factors (diet, consumption of tap water and alcohol, tobacco use (cigarettes), age, gender, age of the home, parents’ occupational activity (a risk factor for children), etc. Esteban, for example, showed that children aged 6 to 10 had higher lead levels than older children (11–17 years), and that girls had lower lead levels than boys. It also demonstrated the persistence of lead exposure factors already known and described in the scientific literature, and enabled the definition of Lead Exposure Reference Values (LERVs) (3). These values serve as a benchmark for comparing blood lead levels measured in an individual or a subgroup of the French population. This makes it possible to identify individuals who are overexposed relative to the reference population. For example, in 2019, a post-fire surveillance system was implemented following the Notre-Dame de Paris fire; 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 to the SNSPE between 2015 and 2018, one-third resided in French Guiana and nearly one-third resided in the Île-de-France region. The Provence-Alpes-Côte d'Azur region accounted for nearly 16% of the cases. The majority were boys (52% of new cases) with an average sex ratio (M/F) of 1.11. Children under the age of 3 accounted for 40% of lead poisoning cases, and among them, 45% were under one year old.

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

Symptoms were uncommon in incident cases (8%); they 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 rare and nonspecific for lead poisoning, these results highlight the importance of identifying poisoned children by screening for environmental risk factors.

Lead exposure remains a public health issue in France. Continued efforts to raise awareness among healthcare professionals about sources of lead exposure enable better identification of children at risk. The findings of Esteban and the SNSPE confirm the need to continue monitoring lead exposure and to keep documenting the associated risk factors. They show that public policy efforts (replacement of lead pipes, lead testing in housing, unleaded gasoline, renovation of older housing, etc.) must be continued. Recently, cases of lead poisoning linked to metal recycling activities have been identified, requiring the implementation of specific preventive measures (5).

Given lead’s toxicity and its harmful effects on health, keeping blood lead levels as low as possible is a public health priority. The results of the national biomonitoring program now provide data to support public policy decisions aimed at continuing efforts to reduce lead exposure (e.g., regulations regarding lead in housing and drinking water pipes, etc.).

The Esteban study demonstrated widespread chemical exposure among the French population using a substance-by-substance approach to identify the determinants of exposure to a specific chemical. In the future, it will be important to focus on multiple exposures to substances to assess the reality of exposure to a cocktail of chemicals. To verify whether levels continue to decline in the general population and whether risk factors persist, the next biomonitoring study should include blood lead measurements, particularly in young children. It would also be beneficial to obtain, through collaboration with other health agencies, environmental data linked to biomonitoring data to identify emerging sources of exposure.

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