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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #337541

Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Zero-valent iron-biosand filtration is capable of reducing antimicrobials and generic E. coli concentrations in unbuffered conventionally-treated reclaimed water: a CONSERVE project

item KULKAMI, PRACHI - University Of Maryland
item RASPANTI, GREG - University Of Maryland
item BUI, ANTHONY - University Of Maryland
item BRADSHAW, RHODEL - University Of Maryland
item Handy, Eric
item Coppock, Cary
item Sharma, Manan
item SAPKOTA, AMIR - University Of Maryland
item SAPKOTA, AMY - University Of Maryland

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: If conventionally treated reclaimed water (RW) is to be adopted as analternative to freshwater irrigation, it is necessary to investigate reuse site-based mitigation options that can further reduce contaminantssuch as foodborne pathogens andpharmaceuticals and personal care products (PPCPs) that may persist in RW. Purpose:To examine the efficacy of a zero-valent iron (ZVI)-biosand filter in removing residual PPCPs, specifically antimicrobials,and generic Escherichia coli (E. coli) present in RW. Methods:Populations of generic E. coli and concentrations of13 antimicrobials commonly found in RW were quantified using the most probable number (MPN) analysis and high performance-liquid chromatography-tandem mass spectrometry, respectively, in unbuffered chlorinated effluent from a tertiary treatmentplant. Testing was conducted before and after filtration through a 50:50; v:v macro-scale ZVI-biosand filter over a two-month period using a greenhouse-based experiment simulating reuse site conditions. The antimicrobials included were ampicillin, oxacillin, penicillin G, ciprofloxacin, oxolinic acid, pipemidic acid, azithromycin, erythromycin, vancomycin, linezolid, sulfamethoxazole, tetracycline and triclocarban.ZVI-filtered RWwas then used to irrigate growing lettuce plants in the greenhouse, and lettuce plants were analyzed for the presence of E. coli after multiple irrigation events. Results:Significant (p-value <0.01) reductions in concentrations were observed after ZVI-biosand filtration for ciprofloxacin, oxolinic acid, pipemidic acid, azithromycin, erythromycin, penicillin, linezolid and vancomycin with 100% reduction achieved for erythromycin. Generic E. coli ranged from 0.36 to 9.3 MPN/100ml in RW and was reduced to between <0.3 and 2.3 MPN/100ml after ZVI-biosand filtration. No E. coli was detected on lettuce after irrigation events. Significance: This greenhouse-based experiment shows promising results for providing a safe alternative to freshwater irrigation by reducing both E. coli populations and potential exposure to antimicrobials in reclaimed water. This study is part ofa three-year effort to explore next-generation mitigation treatments to improve irrigation water quality (CONSERVE).