VULNERABLE POPULATIONS AT THE WORKPLACE

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databases containing ADME* (e.g., ICRP 2002) parameters exist, but data quality and collection process are often unknown. For example, aluminum kinetic data prior to the 1990s were considered less reliable than the current databases due to the lack of ability to differentiate between administered doses and endogenous doses and lack of knowledge of potential contaminations. Some of the existing PBK* models are complicated and may be difficult to communicate when used in health risk assessments. In addition, PBK* models for vulnerable populations, such as pregnant individuals or infants, are scarce. Software used to code toxicokinetic models is diverse, thus operating a given existing model might require specific software. The first step in promoting the development of toxicokinetic modeling is to harmonize toxicokinetic data and store the systematically collected data in a global registry. The second step is to make toxicokinetic models accessible for users to develop human biomonitoring methods and OBL*s. An outline of how this can be achieved has recently been described in (Zare Jeddi et al., 2021c).

Vulnerable populations at the workplace

Vulnerable populations at the workplace include some individuals within the workforce that could have (a) an increased risk of experiencing adverse health effects due to a special disposition and greater sensitivity or (b) a greater potential for elevated exposure to industrial chemicals (NEJAC, 2004, deFur et al., 2007).

 Susceptibility is a component of vulnerability and can be defined as the increased likelihood of an individual worker or workers to be more affected by a chemical as compared to the rest of the workers because of intrinsic biological factors such as life stage, pregnancy, genetic polymorphisms, prior immune reactions, disease state or prior damage to cells or systems (US-

EPA, 2003).  The probability of exposure in a specific work situation can be elevated, for example, due to the poor ability of an individual worker to follow occupational health and safety rules ((ATSDR, 1997); (NEJAC, 2004); (deFur et al., 2007); (US EPA, 2003)).

Traditional workplace risk assessment and management approaches may include vulnerable populations; however, there is no globally accepted approach for HBM-based risk assessments of these sub-populations. HBM data of vulnerable populations can be used as a tool to identify systemic exposure in individuals, who are exceeding biomonitoring guidance values, such as BEI® (USA ACGIH* committee), BLV (ANSES 2021). If exceedances are identified, additional risk management options should be targeted to specific vulnerable groups, such as maternity protection for pregnant or breastfeeding women at the workplace (EEC, 1992). Generic approaches in defining guidance values for exposures at work are usually made for 'healthy workers'. In some specific cases, additional risk management options are targeted to specific vulnerable groups, see for example maternity protection laws (EEC, 1992). There is no globally accepted approach for HBM-based risk assessments for vulnerable populations. One of the advantages of applying individual biomonitoring for exposure and health assessment estimates is that it facilitates the identification of both factors of vulnerability: an eventual higher probability of exposure as well as the higher susceptibility (toxicological vulnerability) influenced by individual kinetic characteristics of substance (uptake, distribution, metabolism, excretion). HBM results can therefore be helpful in identifying vulnerable individuals when exceeding biomonitoring guidance values, such as BEI® (USA ACGIH* committee), BLV (ANSES 2021) and allow taking appropriate measures. Establishing effective communication between key parties (i.e., employers, workers, industrial hygienists, risk assessors and managers, etc.) is crucial in protecting vulnerable workers from health risk from industrial chemicals (Viegas et al., 2020). Finally, it is important to note that labelling individuals into a specific group as vulnerable or marginalized may negatively impact the mental health of affected workers and their career possibilities. Therefore it is important that occupational biomonitoring is based on sound scientific and ethical guidelines, allowing better protection for every worker.

OCCUPATIONAL BIOMONITORING GUIDANCE DOCUMENT © OECD 2022