Usages domestiques de substances biocides et risques de transfert vers le milieu récepteur

The ubiquitous presence of biocidal substances in everyday products, which are used for a wide range of purposes (pesticides, pest control, protection of materials, disinfectants, household or cosmetic products, etc.), raises the question of human exposure and the contribution of domestic activities to the contamination of receiving aquatic environments. It also raises the question of what can be done to reduce these substances at source, since most of them are not eliminated by wastewater treatment plants. An interdisciplinary survey combining the humanities and social sciences with environmental chemistry has provided evidence of the ubiquity of biocidal substances in a very wide range of everyday household products, and of how little users know about them. Their purchasing choices are motivated by habits based on the search for efficiency and cleanliness, with little or no knowledge of the invisible chemical contamination. This chemical pollution was made visible by sampling and analysing greywater, which was collected from volunteers and heavily contaminated with biocides, as a tracer of domestic use and indirectly of exposure. These data highlight the exposure of users to biocidal substances in their domestic sphere and the transfer from upstream to downstream of the sewer system, and ultimately to the receiving aquatic environment. The interviews conducted have enabled us to identify the potential for changing practices, and the levers for action that can be used to reduce pollution at source.