Human Biomonitoring in Occupational Health for Exposure Assessment

My long-time colleague, Dr. John Cocker, used to proclaim human biomonitoring (HBM) a “useful tool” [1]. His reason to do so was to broaden its use as much as possible; only by being widely used and better understood could it really live up to its promise – to enable better exposure control and to evaluate interventions. The primary purpose of HBM in occupational health is exposure assessment, although it can also have a role in health surveillance (e.g., CoSHH regulation 11 [2]). I hope here to demonstrate that HBM really is a useful tool that should be deployed more widely for exposure assessment. Human biomonitoring (also called biological monitoring) is the measurement of the body burden of chemical compounds, elements, or their metabolites, in biological fluids (usually blood or urine, although many media have been used including breath, saliva, hair, nails, etc.). Its role in occupational health is primarily to assess the exposure of workers to the chemicals that they use [3, 4]. In this regard, HBM is another exposure assessment tool alongside environmental monitoring techniques such as air monitoring and surface wipe sampling. The value of HBM over these other tools is that it measures systemic uptake (what has actually got into the body from all sources) rather than potential exposure. The differences between actual (systemic uptake) and potential exposure are influenced by a variety of factors including the physicochemical properties of the substance, the routes of exposure, the use of personal protective equipment (such as respirators and gloves) and the way that tasks are undertaken. To understand the role of HBM, it is useful to consider the exposure-disease paradigm (Fig. 1), a well-known model that shows how environmental toxicants might cause disease. It is a continuum that includes the emission of a contaminant from a source into the environment (air, surfaces, water, etc.) through human exposure and uptake to the occurrence of a health effect [5]. As the exposure and uptake continues, then early, reversible, effects begin to be seen in cells and tissues (measurement of these changes is referred to as biological effect monitoring); if exposure still continues, then eventually the early effects will progress to clinical effects and overt disease will result. The role of occupational health professionals should, above all, be about ill-health prevention, although the aspects of diagnosis, rehabilitation and compensation are also important. And prevention is the guiding principle of HBM; through the identification of excessive exposures and the subsequent evaluation of any interventions, before any health effects are apparent. The efficient use of HBM as a tool in occupational exposure assessment therefore has a number of requirements, including being undertaken by those familiar with the work (the process-