# Mobile genetic elements and wastewater treatment: contaminants of emerging concern, climate change, and trophic transmission

## TL;DR

This review explores how wastewater treatment plants promote the spread of mobile genetic elements, especially through contaminants and climate change effects.

## Contribution

The paper highlights new insights into how emerging contaminants and climate change influence horizontal gene transfer in wastewater treatment systems.

## Key findings

- Emerging contaminants like microplastics and PFAS may enhance horizontal gene transfer in wastewater treatment plants.
- Climate change can disrupt wastewater treatment, increasing genetic element diversity and altering gene transfer dynamics.
- Trophic interactions suggest MGEs can spread from WWTPs to larger organisms, posing risks to ecosystems and human health.

## Abstract

This minireview focuses on recent developments regarding mobile genetic elements (MGEs) and horizontal gene transfer (HGT) in wastewater treatment plants (WWTPs) and proximal environments. WWTPs are often discussed as hotspots and bioreactors for the evolution of MGEs and ARGs and their horizontal transfer. Firstly, the article reviews the effects of emerging contaminants on HGT and MGEs with a specific focus on microplastics and per- and polyfluoroalkyl substances (PFAS). Secondly, the review focuses on how extreme weather and climate change can overwhelm WWTPs, increase the input of diverse genetic elements, and alter the dynamics of HGT. Finally, the trophic connections between the WWTP microbiota and external ecosystems underscore the potential for wider transmission of MGEs. Here, the focus is on transfer of MGEs to larger organisms in the vicinity of WWTPs. In sum, the review focuses on emerging areas of research that refine our understanding of the WWTP environment as a hotspot for HGT and dissemination of MGEs with potentially deleterious implications for human and wider ecosystem health.