The “European Human Biomonitoring Initiative (HBM4EU)” project, or “European Initiative for Human Biomonitoring” in French, brought together more than 100 institutions from 28 European countries. ANSES participated in several aspects of this project, which was coordinated by the German Environment Agency UBA and co-financed by the European “Horizon 2020” program and by the project partners. HBM4EU is interested in human biomonitoring (or biosurveillance) studies, i.e. internal chemical concentrations, found in blood, urine or hair. ” Internal concentrations provide insight into actual exposure to substances, as they consider all sources of exposurethrough air, food, water, skin contact, etc. explains Farida Lamkarkach, Project Manager in the Evaluation of Reference Values and Risks Related to Chemical Substances Unit of the Risk Assessment Department at ANSES.
Linking chemical levels in the body to exposure
However, it is not possible to directly compare the concentrations in the body with the health reference values, which define an exposure threshold below which there is a priori no health risk. In fact, these thresholds are mostly defined on the basis of external exposure concentrations, measured for example in food or air. To find out whether the concentrations measured in the blood or urine corresponded to external exposures exceeding these health reference values, it was therefore necessary reconstruct external exposure to these substances.
Amélie Crépet, Project Manager in the Methodology and Studies Unit of ANSES’s Risk Assessment Department, contributed to this work: ” We started from measurements of internal exposure to different substances, such as bisphenol A, perfluorides or flame retardants, she explains. Taking into account the processes that occur in the bodysuch as absorption, metabolism [transformation des substances par le corps humain]or excretion, we estimated the quantity of substance that might have been ingested or inhaled, in order to compare it with external toxicological reference values. »
The choice of substances to be studied had been the subject of a prioritization work taking into account their dangerousness, the lack of knowledge regarding their effects, as well as the level of potential exposure and the questions surrounding these substances.
Common methods for comparing data between countries
Usually, biomonitoring programs are conducted at the national level. Indeed, the differences in the methods used do not always allow the data to be compared from one country to another. The absence of health reference values for a large number of substances also complicates the interpretation of the observed results. The prioritized substances have therefore been the subject of work to harmonize the methods for assessing their internal concentration. This then allowed set internal guide valuesthat is to say concentrations in the body, in particular in the urine or the blood, which must not be exceeded in order not to risk an effect on the health of the general population and workers.
Ultimately, the values produced as part of this research project might be used to define values applicable in a national and/or European regulatory framework.
In search of the best indicators of internal exposure in the human body
To define these guide values, you have to know what to measure. Sometimes the substance itself can be difficult to assay in a sample blood or urine or not relevant for biological monitoring. In fact, it may be more relevant to look for metabolites, i.e. the compounds resulting from the degradation of the substance in the body. This is, for example, the case of dimethylformamide (DMF), a solvent used in industry. The scientists compared the results from several scientific publications. They thus determined which metabolites resulting from the degradation of DMF showed a better correlation between their concentrations in urine and an effect on health.
Scientists have also defined guide values for the bisphenol A and the bisphenol S in the general and professional population.
For some substances, their work went beyond the simple determination of a guideline value. For example, they estimated the number of people in France, Spain and Belgium who were at risk of osteoporosis due to high cadmium exposure, measured by cadmium concentration in urine.
This work is continuing in the European Partnership for Chemical Risk Assessment (PARC – Partnership for the Assessment of Risks from Chemicals). This 7-year project started on May 1, 2022, it is co-financed by the partners and by the European program “Horizon Europe”, and brings together around 200 partners. It is coordinated by ANSES and mobilizes numerous scientific teams from the agency, who work on different components of the project. It aims to continue the development of new methods for assessing the risks associated with chemical substances.