Household chemicals and personal care products as sources for xenobiotic organic compounds in grey wastewater

Despite contributing 75% of the total wastewater flow to domestic sewers, little is currently known concerning the detailed production patterns and characteristics of grey wastewater. In this study, an inventory of the consumption of household chemicals including a diary survey of water-consuming activities was carried out over seven consecutive days in a block of flats. In total 290 parameters in 92 household chemicals were registered in the inventory in which 30 out of 38 tenants participated. The study was accompanied by quantitative analyses of selected parameters and a screening for organic components in grey wastewater. More than 190 individual components were identified by GC-MS. Identified substances were grouped into eight substance classes based on their application and their concentrations were semi-quantitatively assessed. Several fragrances like citronellol, hexyl cinnamic aldehyde and menthol as well as some preservatives, e.g. citric acid and triclosan, were identified. The measurements also showed that unwanted and unexpected compounds like drugs and pesticides could be present, as well as chemicals not directly deriving from household chemicals or personal care products, e.g. flame-retardants. The inventory provided detailed information about the consumption of various types of household chemicals, but no information on compound concentrations could be assessed due to the limited data in the list of contents of the household chemicals. It was shown that tracking of potentially toxic compounds used in households was possible.