Stockage/utilisation des eaux de pluie : Quelle(s) incidence(s) des pratiques d'entretien des toitures sur la qualité et le potentiel d'usage des eaux de ruissellement ?
Résumé
Although rainwater recycling has been subjected to tax exoneration since 2006 for individuals, its use was approved, for interiors only, in August 2008. However, little consideration has been given to the roof runoff quality, its potential use, and to the maintenance procedures of the roof surface and the runoff recuperation tank. The products used for cleaning and maintenance of rooftops may be a major source of organic pollutants in the collected waters. After listing the products, four possible treatments were identified: primary cleaning, fungicide treatment, waterproofing and paint. Some of these specific products include a biocide action. Quaternary ammonium compounds and isothiazolinone derived compounds have been underlined. These both molecules are very toxic for aquatic organisms, with EC50 down of 1 mg.L-1. Moreover an investigation work shown that fungicide treatment and waterproofing are the two most current practices. Finally, it has been brought to light that several treatments are operated by unprofessional people, hence neither the products nor the methods used are easily recognizable.