Abstract

The reuse of treated wastewater (TWW) has been considered a suitable alternative for agriculture and for achieving water security and management. However, this practice may contribute to the dissemination of antibiotic resistance genes (ARGs) into the environment, a matter of global concern. The aim of this study is to discuss the reuse of TWW in agriculture under the perspective of the risks associated to ARGs dissemination. An exhaustive bibliographic research was conducted for determining the capacity of reducing ARG loads for different wastewater treatment technologies (conventional, non-conventional and advanced technologies). Moreover, the distribution of ARG elements in crops irrigated with TWW was also reviewed for discussing the potential health risks associated to the TWW reuse. Reduction of ARG loads in conventional, non-conventional and advanced treatments fluctuated between 1.1 and 4.1, 0.1-2.1 and 0.1-9.5 log units, respectively. These variable ranges indicate that operational parameters, plant design, and water quality are fundamental parameters determining their performance and their capacity to reduce ARG dissemination. In the case of ARG distribution in crops and soil irrigated by TWW, higher abundances were observed in soil than edible parts of crops with ranges between (- 0.7)-6.0 log copies/g of soil and (- 0.9)-5.6 log copies/g of soil, respectively. The occurrence of ARGs in crops may represent a relevant human exposure to ARG-harbouring bacteria and therefore, a potential human health risk that requires the establishment of safe procedures and legislation for assuring a safe reuse of TWW.