Harmonising data to better understand the actual chemical exposure of Europeans
The European Human Biomonitoring Initiative (HBM4EU) was the first large-scale European project aiming to harmonise measurements of exposure to chemicals in the population and assess the health effects of this exposure. Having started on 1 January 2017, it ended with a closing meeting in late June 2022. Below we look back at ANSES's contributions, which helped prioritise the substances to be studied and define guidance values associated with health risks for several substances.
HBM4EU brought together over 100 institutions from 28 European countries. ANSES was involved in several parts of this project, which was coordinated by the German Environment Agency (UBA) and funded jointly by the European Horizon 2020 programme and the project’s partners. HBM4EU focused on human biomonitoring studies, i.e. on internal concentrations of chemicals found in blood, urine and hair. "Internal concentrations help us better understand actual exposure to substances, because they take all routes of exposure into account, including air, food, water, and skin contact” explains Farida Lamkarkach, Project Manager in the Unit for Assessment of Chemical Reference Values and Risks of ANSES's Risk Assessment Department.
Establishing a link between exposure and concentrations of chemicals in the body
However, concentrations in the body cannot be directly compared with the health reference values, which define a threshold of exposure below which there do not seem to be any health risks. This is because these thresholds are mainly defined based on external exposure concentrations, measured for example in food or air. To find out whether the concentrations measured in blood or urine corresponded to external exposure exceeding these health reference values, it was therefore necessary to reconstruct external exposure to these substances.
Amélie Crépet, Project Manager in the Methodology and Studies Unit of ANSES's Risk Assessment Department, was involved in this work: "We started with measurements of internal exposure to various substances, such as bisphenol A, perfluorinated compounds and flame retardants” she explains. “Taking into account the processes that take place in the body, such as absorption, metabolism [transformation of substances by the human body] and excretion, we estimated the amount of substance that may have been ingested or inhaled, in order to compare it with the external toxicity reference values”.
Work was undertaken to prioritise the substances to be studied, in light of their dangerousness, the lack of knowledge on their effects, the potential exposure level, and the questions surrounding them.
Shared methods for comparing data between countries
Usually, biomonitoring programmes are carried out at national level. Because of the different methods used, data cannot always be compared from one country to the next. Many substances have no health reference values, which also means it is complicated to interpret the observed results. Work therefore focused on the prioritised substances in order to harmonise the methods used to assess their internal concentrations. This led to the definition of internal guidance values, i.e. concentrations in the body, in particular in urine or blood, that should not be exceeded to avoid any potential effect on the health of the general public and workers.
Over time, the values produced during this project may be used to define values that could be applied in a national and/or European regulatory framework.
Searching for the best indicators of internal exposure in the human body
To define these guidance values, it is necessary to know what to measure. Sometimes, the substance itself may be difficult to measure in a sample of blood or urine or may not be relevant for biomonitoring. As a result, it may be more appropriate to test for metabolites, i.e. compounds produced when a substance breaks down in the body. This is the case, for example, of dimethylformamide (DMA), a solvent used in industry. Scientists compared the results found in several scientific publications. This helped them determine which DMF metabolites showed the best correlation between their concentrations in urine and an effect on health.
The scientists also defined guidance values for bisphenol A and bisphenol S for the general public and for workers.
For certain substances, their work went beyond the simple determination of a guidance value. For example, they estimated the number of people in France, Spain and Belgium who were at risk of osteoporosis due to a high level of exposure to cadmium, based on the concentration of cadmium measured in urine.
This work is continuing under the European Partnership for the Assessment of Risks from Chemicals (PARC). This seven-year project bringing together around 200 partners started on 1 May 2022. It is co-funded by its partners and the European Horizon Europe programme. Coordinated by ANSES, it has mobilised several of the agency's scientific teams, who are working on the project’s various components. It aims to continue developing new methods for assessing risks related to chemical substances.