An Analysis of BTEX Occurrence in Stored Rainwater and Rainwater Runoff in Urban Environment

Climate change and its effects, for instance drought, drive the search for alternative water sources. One of these sources is rainwater, especially the runoff from various roof surfaces in cities. In turn, its use in the city for the production of food as part of hydroponic and aquaponic systems requires knowledge of possible pollutants and their varied concentrations. In this article, the concentrations of benzene, toluene, ethylbenzene, and xylene (BTEX) in rainwater collected in cities from various surfaces and stored in various types of tanks (open and closed) are analysed. Tests were carried out on extracted specimens using gas chromatography with a flame ionisation detector (FID). BTEX compounds were determined using a chromatograph with a FID sensor and a capillary column. Organic substances were extracted from the water with dichloromethane. The possibility of occurrence of BTEX compounds in rainwater flowing down from various roof surfaces in the city was confirmed. The obtained results suggest future research directions for mitigating BTEX rainwater pollution in order to expand the scope of its subsequent use. Preliminary guidelines for its treatment based on the literature were proposed. The possibility of using urban rainwater for hydroponic and aquaponic systems was assessed in terms of BTEX content.