Effects of Phosphate on the Transport of Escherichia coli O157:H7 in Saturated Quartz Sand

Consumption of groundwater contaminated with E. coli O157:H7 has led to several waterborne disease outbreaks over the past decade. A thorough understanding of the transport of E. coli O157:H7 within the soil-groundwater system is critical to the protection of public health. Although phosphate is ubi...

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Bibliographic Details
Published in:Environmental science & technology 2011-11, Vol.45 (22), p.9566-9573
Main Authors: Wang, Lixia, Xu, Shangping, Li, Jin
Format: Article
Language:English
Subjects:
Air. Soil. Water. Waste. Feeding
Applied sciences
Biological and medical sciences
Cells
E coli
Environment. Living conditions
Environmental Processes
Escherichia coli Infections - epidemiology
Escherichia coli O157 - physiology
Exact sciences and technology
Groundwater
Groundwater - microbiology
Groundwaters
Humans
Medical sciences
Natural water pollution
Osmolar Concentration
Phosphates
Phosphates - chemistry
Pollution
Public Health
Public health. Hygiene
Public health. Hygiene-occupational medicine
Silicon Dioxide - chemistry
Soil Microbiology
Water treatment and pollution
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Summary:Consumption of groundwater contaminated with E. coli O157:H7 has led to several waterborne disease outbreaks over the past decade. A thorough understanding of the transport of E. coli O157:H7 within the soil-groundwater system is critical to the protection of public health. Although phosphate is ubiquitous in the natural environment, the influence of phosphate on the transport of E. coli O157:H7 in the groundwater system remains unknown. In this research, we performed column transport experiments to evaluate the effect of phosphate on the transport of E. coli O157:H7 cells within saturated sand. The pH of the solutions was maintained at 7.2, the ionic strength varied from 10 to 100 mM, and the phosphate concentration ranged from 0 to 1 mM. Our results show that (1) phosphate could enhance the transport of E. coli O157:H7 cells under both ionic strength conditions; (2) E. coli O157:H7 displayed lower retention in sand under higher ionic strength conditions; (3) increased phosphate in the mobile aqueous phase led to the release of previously immobilized E. coli O157:H7 cells. The response of E. coli O157:H7 cells to variations in phosphate concentrations and ionic strength conditions are explained using the extended DLVO (XDLVO) theory and the steric repulsion caused by extracellular macromolecules. In summary, our results suggest that phosphate could widen the spread of E. coli O157:H7 cells, and potentially other types of bacterial cells, within the soil-groundwater system.
ISSN:0013-936X
1520-5851
DOI:10.1021/es201132s