Objectives Lead poisoning is a major public health problem worldwide. In French Guiana, a French overseas territory in South America, several studies have highlighted the massive lead impregnation of the local population, but the risk factors have not yet been fully elucidated. People working in informal gold mining share part of their lifestyle with French Guianese communities. The aim of this was therefore to estimate the level of lead poisoning in this population and the factors associated with it.

Methods This cross-sectional descriptive study was based on data collected by questionnaire and blood sampling. Persons working in informal gold mines were enrolled on the logistic rear bases on the Surinamese and Brazilian sites of the bordering rivers. Blood lead levels were measured on dry blood spots (50 µl). Using a threshold of 100 μg.L-1, single and multiple regressions were used to assess the associated factors.

Results Among the 526 persons included, the median age was 38 years and 73.5% were men. The prevalence of lead poisoning was 44.7 % (95%CI=40.4%-49.0%). The factors associated with a BLL over 100 μg.L-1 were: amount of time spent in gold mining (OR=1.31 [1.09-1.58], occupation with mud exposure (OR=1.67 [1.13-2.48]), working in the Southwestern region (OR=2.09 [1.34-3.27]) and consuming game (OR=1.58 [1.06-2.36]).

Conclusion The people working on gold mining sites are highly exposed to lead poisoning. The risk factors are suggestive of environmental contamination and differ from those suspected in the population of French Guiana.

What is already known on this topic Lead poisoning has a major impact on health. Although, its risk factors are well known in the Western world, they are different in the Amazon. In French Guiana, a French overseas territory in South America, lead poisoning is very common in the local population, but the risk factors are still poorly understood. So far, the suspected sources of lead poisoning are the bioaccumulation of lead in cassava flour, lead contained in hunting ammunition, lead used to weigh the fishing nets, and lead spills from used lead batteries.

What this study adds This study shows, for the first time, the high lead impregnation of the population living and working on illegal gold mining sites in French Guiana. Although some aspects of their lifestyles are shared with the local population, the risk factors we observed were different from those commonly hypothesized. We found that length of time spent in gold mining, and activities in close contact with mud were significantly associated with lead poisoning.

How this study might affect research, practice or policy The contrast between the factors associated with lead poisoning in the local population and in the population working at the gold mining sites allows to propose new hypotheses and research questions to be proposed about potential sources of contamination, for example related to local geology.

The authors have declared no competing interest.

The study was funded by the European Regional Development Fund (FEDER) via the Interregional Amazon Cooperation Program (IACP) 2014-2020 and the Regional Health Agency. The funders have no role in the analysis and publication process.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

A written consent form was collected after information in the participant language on the primary objective of the study related to malaria and secondary objectives related to heavy metal poisoning. The study obtained authorization from the Surinamese Ministry of Public Health (N-CMWO005) and from the Brazilian National Research Ethics Commission (N-5.507.241) as part of the Curema project. The authorization of importation of human biological samples was obtained (IE-2022-2169) and the biological collection declared to the French Ministry of Education and Research. The database was anonymized and registered according to the General Data Protection Regulation (GDPR). This study was conducted in accordance with the principles set forth in the Declaration of Helsinki

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All data produced in the present study are available upon reasonable request to the authors