FOR 5095:  Pollutant – Antibiotic Resistance – Pathogen Interactions in a Changing Wastewater Irrigation System

• Subject Area: Agriculture, Forestry and Veterinary Medicine
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431531292

Wastewater reuse for irrigation is a crucial leverage point for increasing the efficiency of water usage, decreasing water shortages and raising food production. Water treatment prior to its use in agriculture is generally advocated for reducing environmental and health risks of wastewater irrigation. However, while replacing untreated with treated wastewater may reduce the loads of nutrients, carbon and many pollutants that reach irrigated fields, it can mobilize pollutants that soils have accumulated in the past. Therefore, we hypothesize that hitherto unforeseen risks arise from the implementation of conventional wastewater treatment in long-established wastewater irrigation systems, due to i) the release of pollutants that have formerly been accumulated in soils leading to concentrations that (co-)select for antimicrobial resistance and ii) an increased selection and spreading of resistant bacteria and resistance genes. Yet, the magnitude and relevance of these emerging risks cannot be predicted because we lack fundamental understanding of (co-)selection processes of multiple resistant bacteria and transfer of resistance genes at sub-inhibitory concentrations of antibiotics and disinfectants and their combinations in soils and plants. Moreover, spatial and sorptive controls for these interactions are largely unknown. Nothing is also known regarding the coupling of fate and effects of antibiotics and disinfectants under subtropical conditions, where high temperatures can promote both, the selection of resistant bacteria harboring transferable resistance plasmids, but also the dissipation of organic pollutants, so far to an unknown degree. The implementation of water treatment in the world´s largest wastewater irrigation system, the Mexico City-Mezquital Valley, offers the unique chance to gain the required process understanding for assessing the above mentioned risks. The proposed Research Unit will thus elucidate the mechanisms controlling the dynamics of pollutants and multiple resistant bacteria during the transition from irrigation with untreated wastewater to irrigation with treated water. This Research Unit will deliver fundamental process understanding regarding the interaction of the fate of different pollutants, bacteria, and the spreading and selection of antibiotic resistance in agroecosystems.

• DFG Programme: Research Units
• International Connection: Mexico

Projects

• Coordination Funds (Applicant Siemens, Jan )
• Effects of irrigation water quality and soil type on the soil and plant associated microbiome, abundance, diversity and transferability of antibiotic resistance genes in Gram-negative bacteria (Applicant Smalla, Kornelia )
• Effects of irrigation water quality and soil type on the soil and plant associated microbiome, abundance, diversity and transferability of antibiotic resistance genes in Gram-positive bacteria (Applicant Grohmann, Elisabeth )
• Evolution and selection of resistant bacteria in the presence of subinhibitory concentrations of micropollutants (Applicant Bierbaum, Gabriele )
• Integrated modelling of the selection of resistant bacteria and horizontal transfer of resistance genes caused by exposure to antibiotics and disinfectants (Applicant Zarfl, Christiane )
• Isolation and characterization of environmental and fecal bacteria carrying antibiotic resistance genes (Applicant Glaeser, Stefanie P. )
• Release and dissipation of antibiotics and disinfectants in different soil types as influenced by irrigation water quality (Applicants Mulder, Ines ;  Siemens, Jan )
• Role of natural nanoparticles and colloids for the mobility and bioavailability of antibiotics in soil (Applicants Amelung, Wulf ;  Braun, Melanie )

• Spokesperson: Professor Dr. Jan Siemens