Source bioaerosol concentration and rRNA gene-based identification of microorganisms aerosolized at a flood irrigation wastewater reuse site.
Reuse of partially treated domestic wastewater for agricultural irrigation is a growing practice in arid regions throughout the world. A field sampling campaign to determine bioaerosol concentration, culturability, and identity at various wind speeds was conducted at a flooded wastewater irrigation site in Mexicali, Baja California, Mexico. Direct fluorescent microscopy measurements for total microorganisms, culture-based assays for heterotrophs and gram-negative enteric bacteria, and small-subunit rRNA gene-based cloning were used for microbial characterizations of aerosols and effluent wastewater samples. Bioaerosol results were divided into two wind speed regimens: (i) below 1.9 m/s, average speed 0.5 m/s, and (ii) above 1.9 m/s, average speed 4.5 m/s. Average air-borne concentration of total microorganisms, culturable heterotrophs, and gram-negative enteric bacteria were, respectively, 1.1, 4.2, and 6.2 orders of magnitude greater during the high-wind-speed regimen. Small-subunit rRNA gene clone libraries processed from samples from air and the irrigation effluent wastewater during a high-wind sampling event indicate that the majority of air clone sequences were more than 98% similar to clone sequences retrieved from the effluent wastewater sample. Overall results indicate that wind is a potential aerosolization mechanism of viable wastewater microorganisms at flood irrigation sites.
Paez-Rubio
Tania
T
Department of Civil and Environmental Engineering, Arizona State University, Tempe, AZ 85287, USA.
Viau
Emily
E
Romero-Hernandez
Socorro
S
Peccia
Jordan
J
D000336:Aerosols; D000383:Agriculture / Q000379:methods*; D000391:Air Microbiology; D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D003001:Cloning, Molecular; D015169:Colony Count, Microbial; D056890:Eukaryota / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D000461:Rhodophyta / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D014865:Waste Disposal, Fluid / Q000379:methods*; D014871:Water Microbiology
D000336:Aerosols