256b - Why and how to do biological monitoring?

Abstract Depending on the evidence available, BEI® values are set at concentrations equivalent to air concentrations or at a level below that where any adverse effects are observed; many of the current values are set at the equivalent of the TLV-TWA. Given this, you might think, why not just do air monitoring? However air monitoring does not take into account the possibility of systemic uptake through other routes (skin absorption, ingestion via hand-to-mouth behaviour), the use of personal protective equipment (such as respirators) or the impact of worker behaviour on their own exposure. Once you have decided to implement a biological monitoring (BM) programme, it is essential to plan appropriately; ACGIH provides materials to assist with this. Most BM sampling will require samples to be sent to an appropriate laboratory for analysis. Where possible, the laboratory should specialise in BM but availability of such laboratories is limited and often clinical or analytical chemistry laboratories will be used. It is important to ascertain that the laboratory understands the methodology to be used (including nuances such as hydrolysis of certain metabolites) and that they participate in an appropriate quality assurance scheme. There are a number of schemes available; one of the most extensive and established is G-EQUAS with over 200 participants in 40 countries taking part in 2023. With appropriate planning and implementation, a biological monitoring programme can have a positive impact in reducing workplace exposure and engaging workers in their own health protection.