Non-invasive biomonitoring tools and biomarkers of exposure and effect

Advances with analytical techniques for the identification and quantification of pesticides allows sensitive biomarker techniques to be developed to measure and monitor the exposure to pesticides and the early signs of potential health effects. Until recently urine samples taken over a 24-48 hour period were one of the best ways of measuring exposure. To obtain more detailed information, blood samples needed to be taken to measure markers such as cholinesterase levels for organophosphate or carbamate exposure.  It is now possible to measure levels of certain pesticides in a non-invasive manner, such as in the nails or hair of agricultural workers, identifying both the parent compound and metabolites. The use of toxicokinetic modelling allows spot urine samples to yield more information than previously, avoiding the need for whole day urine sampling. Developments with QSAR (Quantitative structure-activity relationships) are also identifying potential metabolites based on the structure of the parent compound, which together with TOF (Time of Flight) detection techniques can provide a comprehensive picture of the metabolite profile over time between exposure points. The use of blood spot samples from a finger prick in the pharmaceutical industry is becoming well established and now offers the potential for use in the area of pesticide exposure.  Sensitive analytical techniques and knowledge of biochemical pathways are therefore leading to a greater understanding of the fate of pesticides in the human body, and allowing key biomarkers of effect to be identified, with the potential for use as indicators or early warnings of adverse health effects before irreparable damage is done.