D5.1 - Human biomonitoring in risk assessment: analysis of the current practice and 1st examples on the use of HBM in risk assessments of HBM4EU priority chemicals
Creators: name: Santonen, Tiina
Publisher: name: Zenodo
Year: 2017
Subjects: Human biomonitoring
risk assessment

description: In chemicals risk assessment frameworks, the default approach is to assess external intake from different sources of exposure and via different routes of exposure. They are often assessed separately. This approach includes various uncertainties and often overestimates the real uptake since default, conservative estimates are used e.g. for the absorption of the chemical. At the same time, actual (real life) exposure may be underestimated by not taking into account that exposure to a chemical substance may occur from different sources, which may fall under separate legislative frameworks. Examples are triclosan that is used in biocidal products as well as in consumer products and importantly, most if not all chemicals that are produced by workers where at the same time these workers may be exposed as part of the general population. In some cases, other tools to assess exposure via all possible routes may be insufficient; an example is occupational exposure via hand-to-mount exposure, which has been shown to occur for example in the case of many metals, like lead, through contaminated hands. Without biomonitoring, exposure in these cases could become severely underestimated. Human Biomonitoring (HBM) is an important tool to survey the real life body burden – or internal exposure – of humans resulting from ‘total’ exposure to chemicals via different routes (lung, skin, digestive tract) and ‘via’ different legislative frameworks on chemicals. By providing more accurate data on actual body burdens (internal exposure), inclusion of HBM data could improve human health risk assessment for both the general population (exposure via air, consumer products, drinking water and food) as well as for workers (exposure via inhalation and/or skin) separately or as part of the population. HBM could be helpful in other areas as well, demonstrating for example increased blood levels because of accumulation of a chemical in the body following repeated exposure. In many frameworks, human absorption, distribution, metabolism, and excretion (ADME) and toxicokinetics data including the body half-life are not necessarily required for the safety assessment of the chemical. HBM has also been used to showcase that interindividual differences with respect to respiratory ventilation and use of personal protection equipment are reflected in internal exposure. These differences are not observed using ambient air monitoring. In addition, by using HBM data it could be possible to bridge with new conceptual developments such as AOPs (adverse outcome pathways) and to investigate direct linkages between internal exposure and the onset of AOPs resulting in adverse health effects. Naturally, HBM has also limitations including the fact that it often gives only a snap shot of exposure due to the assessment of single time points, often metabolites and not the parent compounds are measured, and exposure biomarkers are only proxies measured in easily accessible tissues and fluids and are not necessarily the concentrations at target organs. In addition, total body burden may be in some cases difficult to link to specific exposure sources. These limitations need to be recognised when interpreting biomonitoring data. Although the past few years have shown good examples on the use of HBM in the risk assessment of chemicals, there is still quite some work to improve its use in risk assessment and human impact assessment. As a matter of fact, the US National Academies of Sciences, Engineering and Medicine in a recently released report on ”Using 21st Century Science to Improve Risk-Related Evaluations” (US NAS, 2017), lays out recommendations to incorporate the emerging science into risk-based evaluations. In that capacity, HBM is described as an essential tool allowing for advances in exposure science and epidemiology. Therefore, the HBM4EU project aims to deliver European wide quantitative information on levels of internal exposure biomarkers and effect biomarkers. Using thousands of individually linked pieces of information on exposure and health-effect biomarkers, the aim is to establish ‘internal exposure-health effect relationships’. If successful, this will provide molecular epidemiological (= legislative framework independent) knowledge that could be used alongside the classical toxicological, regulatory framework-driven risk assessment. Moreover and at the same time, using the newly developed ‘internal exposure - health effect relationships’, health impact assessment (HIA) of chemicals would become more feasible. Altogether, improvement and the combined use of human health risk assessment and HIA will provide the necessary tools for a significant step forward in the important domain of chemicals risk management. In order to achieve this goal and to provide strong anchoring to current risk assessment practices, in this report, the current use of human biomonitoring in risk assessment of chemicals has been evaluated. Firstly, different global (World Health Organization (WHO), Food and Agriculture Organization of the United States (UN FAO)) and regional (EU) risk assessment schemes were screened for information on HBM including the availability of guidance on how to use HBM in risk assessment. In addition, a survey was held to collect information from national regulatory risk assessors on their day to day risk assessment practices, the use of HBM, and obstacles and challenges related to the use of HBM (in EU, European non-EU as well as non-European countries). Finally, we have presented good examples on the advanced use of human biomonitoring of a few selected chemicals from the HBM4EU prioritised substance groups. Based on these data some proposals are provided for the better inclusion of HBM in human risk assessment and health impact assessment.
description: {"references": ["Ref. Ares(2017)5600435 - 16/11/2017"]}