6 Moss biomonitoring as an alternative to assess exposure to atmospheric metals in environmental epidemiology: the example of the bramm network and the gazel cohort

Background/aim Measuring atmospheric metals is challenging due to their low concentrations in the air and the cost of measurements using conventional devices in monitoring stations. To conduct epidemiological research on exposure to atmospheric metals we must expand the network of monitoring stations, or find different ways of quantifying levels of atmospheric metals. Methods Fortunately, such an alternative exists in an unexpected form: the moss biomonitoring approach, based on the ability of mosses to proxy levels of atmospheric metals. Our objective is to assess the feasibility to assign atmospheric metals exposure estimates, using moss biomonitoring, in an epidemiological cohort. Framed by BRAMM, the French network of moss biomonitoring, mosses were surveyed for their content in 13 metals including Hg and Pb in1996, 2000, 2006 and 2011 in 449–559 forest sites. After sample preparation and chemical analyses, data were interpolated by kriging to produce 2 × 2 km maps, from which we extracted levels of atmospheric metals at the residential address of GAZEL’s participants. Results As biomonitoring data comes from mostly rural areas, we estimated exposures to atmospheric metals for for 11 382 participants of the GAZEL population living in low to moderate population density areas. We obtained a high spatial and temporal variability of exposure for all metals (e.g. 38 to 139 ng.g-1 for Hg, or 1.8 to 49.8 mg.g-1 for Pb). Exposures to all metals followed gradients of population density and showed higher concentrations in industrial regions, such as the Parisian region, the North or the Rhone valley. Conclusion Moss biomonitoring is a convincing tool to assess exposure to atmospheric metals, at least in non-urban areas, and can be easily associated to epidemiological data. Further research will investigate the possibility to collect and use moss biomonitoring in urban areas for epidemiological purposes.