Exposure and risk profiles: From field studies to typical exposure and risk scenarios

Pesticides are among the most employed synthetic chemicals, and for which there, is the largest database of chemical and toxicological information that allows establishing health-based exposure limits. Protection of pesticide applicators and of the general population from over-exposure is both an ethical necessity and a contribution to planetary health. So far the exposure occupational and population exposure limits could not be efficiently used for health protection, due to the limitations of current techniques to be employed on a wide scale. Biological monitoring of exposure is a viable technique for occupational protection and for the assessment of chemical risk of the population Pesticides are intrinsically toxic, and their manipulated quantity and wide use requires adequate protection to reduce the potential impact on applicators’ health. Before marketing the exposure-related health risk of each active substance is assessed through models, to demonstrate that at least in one application scenario its use does not cause an unacceptable health risk to the exposed workers. This reasonably safe scenario identifies the modalities for an effective and safe use that are coded as “Good Agricultural Practices” (GAP) and summarized in the label's instructions. However, real-life work may be conducted out of the frame of GAP, with a consequent health risk for the exposed workers, which must be assessed and managed. In real-life working conditions, risk assessment is seldom, if at all, performed since the task is linked to economic cost, the limited availability of trained personnel and logistics necessary to reach small, family-based enterprises, which are poorly covered by occupational health services. Additional difficulties are represented by the variability of working patterns, climatic conditions, and the frequent use of mixtures of pesticides. The main tools currently available for the exposure and risk assessment “in the field,” namely, biological and environmental monitoring, show important limits for their use in agriculture. In particular, assessment of dermal contamination involves very complicated and expensive procedures that cannot be carried out on a routine basis. Biological monitoring faces strong limitations, including lack of fully validated biomarkers and biological exposure limits. The exposure estimate and risk estimate done for a specific worker at a specific time during one of his workdays using any of the aforementioned methods represent only one point on a map of exposures and risk for workers applying pesticides. Instead of a point, we are interested in the whole map of exposure and risk. To make risk assessment available to all workers in various working conditions, there is a need of simple, user-friendly, and reliable approaches to estimate the levels of exposure (and of related occupational risk) experienced by the workers during typical, rather than actual, activities. We refer to these typical conditions as exposure and risk profiles. This chapter underlines the variables influencing exposure and exposure assessment in real-life work scenarios, reviews the drawback and difficulties of performing exposure assessment using environmental and/or biological monitoring, introduces the concept of exposure scenarios and risk profiles, reviews the current state of risk profile development and their main characteristics, and presents a way forward to integrate the exposure assessment through the exposure score (or index) and the toxicity score to create a risk assessment scheme or a map of exposure and risk in typical exposure scenarios. when measurements can be compared with suitable limit values. This possibility is currently employed only for few metals and organics of industrial interest, but only insufficiently for pesticides. We propose a paradigm to assess exposure and exposure-related risk of pesticides based on the measurement of their metabolites excreted in urine and on the elaboration of results from field exposure studies. Regression models allow forecasting the pesticide excretion associated to a systemic dose of pesticide corresponding to its acceptable occupational exposure limit (AOEL) for agricultural pesticide applicators. For this indicator and its corresponding limit value, we propose the name of equivalent biological exposure limit (EBEL). To demonstrate the proposed procedure and to highlight its utility and current limitations, we report data and elaborations from a previously published study that allows establishing a provisional value for an herbicide. This procedure can be adapted to fill the identified sources of uncertainty and to derive a limit value that