**7. Conclusions**

The paper reviewed recent findings on the applications of wetlands for the treatment of agricultural wastewater that contained pesticides and herbicides, veterinary medicines, antimicrobial resistant bacteria, or ARGs. By the volume of the search results, it can be concluded that these topics are understudied but are gaining major attention lately, likely due to concerns with ARGs. Wetlands are nature-based treatment systems, which are capable of treating many pollutants in the agricultural wastewater simultaneously by utilizing several physico-chemical and biological mechanisms. For example, adsorption to the substrate and plant's root (physical process), microbial metabolization and degradation (biological and chemical processes), and plant uptake (biological process) were found to be responsible for removal of veterinary medicines. While a major removal mechanism for antibiotics was microbial degradation, substrate sorption was a major mechanism for ARGs. The major parameters, such as target contaminants' property, aeration condition, types and designs of CWs, hydraulic parameters, substrate medium and vegetation that impact the CW system's removal performances, were also discussed to provide suggestions for successful future designs. Since CWs are adaptable to various wastewater treatments with satisfying removal efficiencies, CWs can be a key tool to fight against current and emerging environmental problems, especially when resilient and climate smart solutions are needed more than ever.

**Author Contributions:** Conceptualization, N.A. and Z.T.; writing—original draft preparation, J.W., Z.T., D.S. and A.T.; writing—review and editing, N.A. and Z.T.; supervision and project administration, N.A.; funding acquisition, N.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by Grant project number NC.X333-5-21-130-1 and Capacity Building Grants Program gran<sup>t</sup> no. 2020-38821-31114 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

**Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
