Atrazine degradation by bioaugmented sediment from constructed wetlands

Area of Science:

• Environmental Microbiology
• Bioremediation
• Wetland Science

Background:

• Pesticide contamination in constructed wetlands poses environmental risks.
• Biodegradation of pesticides like atrazine is crucial for remediation.
• Enhancing microbial degradation in wetland sediments is a key challenge.

Purpose of the Study:

• To investigate the potential of bioaugmentation for establishing pesticide biodegradation in constructed wetland sediment.
• To assess the effectiveness of introducing atrazine-degrading microorganisms.
• To compare bioaugmentation with organic amendments for atrazine removal.

Main Methods:

• Microcosm experiments with bioaugmented and unbioaugmented sediment.
• Use of 14C-labeled ethyl atrazine to track mineralization.
• Incubation under unsaturated and water-saturated conditions.
• Mesocosm studies with cattails (Typha latifolia).

Main Results:

• Bioaugmentation increased atrazine mineralization by 25-30% compared to 2-3% in unbioaugmented sediment.
• Atrazine and its metabolites were undetectable post-incubation in bioaugmented sediment.
• Bioaugmentation significantly increased the population of atrazine-degrading microorganisms.
• Degrader populations and mineralization rates were high in mesocosms with atrazine.

Conclusions:

• Bioaugmentation is an effective method for establishing pesticide biodegradation in constructed wetland sediments.
• This approach can significantly reduce atrazine and metabolite concentrations.
• Bioaugmentation shows potential for treating pesticide contamination in nursery runoff, provided degrader persistence is adequate.