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Wetland treatment systems are used extensively across the world to mitigate surface runoff. While wetland treatment for nitrogen mitigation has been comprehensively reviewed, the implications of common-use pesticides and antibiotics on nitrogen reduction remain relatively unreviewed. Therefore, this review seeks to comprehensively assess the removal of commonly used pesticides and antibiotics and their implications for nitrogen removal in wetland treatment systems receiving non-point source runoff from urban and agricultural landscapes. A total of 181 primary studies were identified spanning 37 countries. Most of the reviewed publications studied pesticides (n = 153) entering wetlands systems, while antibiotics (n = 29) had fewer publications. Even fewer publications reviewed the impact of influent mixtures on nitrogen removal processes in wetlands (n = 16). Removal efficiencies for antibiotics (35–100%), pesticides (−619–100%), and nitrate-nitrogen (−113–100%) varied widely across the studies, with pesticides and antibiotics impacting microbial communities, the presence and type of vegetation, timing, and hydrology in wetland ecosystems. However, implications for the nitrogen cycle were dependent on the specific emerging contaminant present. A significant knowledge gap remains in how wetland treatment systems are used to treat non-point source mixtures that contain nutrients, pesticides, and antibiotics, resulting in an unknown regarding nitrogen removal efficiency as runoff contaminant mixtures evolve.
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Wetland Removal Mechanisms for Emerging Contaminants
In recent decades, previously unobserved trace compounds have become more widely detected in wastewater treatment effluents and freshwater ecosystems. Emanating from various sources and presenting potential human health and ecological risks at much lesser concentrations than traditional contaminants, detection of “emerging contaminants” has increased with improvements in analytical techniques. The behavior of emerging contaminants in wetlands is a topic of increasing interest, as natural wetlands are known to transform and sequester pollutants and constructed or treatment wetlands are widely utilized to address elevated concentrations of constituents of concern. Both natural and constructed wetlands are complex biogeochemical systems with interrelated abiotic and biotic mechanisms leading to the removal of emerging contaminants. A literature review was performed to assess the current state of knowledge of various wetland mechanisms involved in removing these contaminants from surface waters and effluents. The primary mechanisms discussed in the literature are sorption, photodegradation, microbial biodegradation and phytoremediation. The most influential mechanisms are dependent on the properties of the contaminants and wetland systems studied. Common trends exist for different constructed wetland designs to leverage various mechanisms based on hydrology, substrate and vegetation plantings. Much remains to be understood about the various processes occurring in wetlands as they relate to emerging contaminant removal. Improving the understanding of the potential role of wetland mechanisms can help manage this environmental challenge more effectively.
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- Award ID(s):
- 1946093
- PAR ID:
- 10402297
- Date Published:
- Journal Name:
- Land
- Volume:
- 12
- Issue:
- 2
- ISSN:
- 2073-445X
- Page Range / eLocation ID:
- 472
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/land12020472
