Preferential Flow and Transport of Cryptosporidium parvum Oocysts through the Vadose Zone: Experiments and Modeling

Abstract. Water flow and solute transport through a fractured vadose zone underneath an industrial contaminated site in Belgium were studied with a new methodological concept. The Vadose Zone Experimental Setup (VZES) combines a vadose zone monitoring system (VMS) with cross-borehole geophysics. The VMS provides continuous chemical and hydraulic information at multiple depths in the vadose zone. When combining such information with multidirectional subsurface imaging from geophysical measurements, flow and transport can be characterized at a scale that covers the spatial variability of the subsurface. The setup was installed on site and monitoring was carried out under natural recharge conditions. Results reveal quick rises in water content as a response to rainfall events in the upper and intermediate part of the vadose zone (down to 3.65 m depth). Macropore, micropore, matrix and preferential flow mechanisms are identified at these depth ranges. At greater depths, flow dynamics is slower and dominated by matrix flow. The governance of water flow mechanisms at different directions is controlled by the heterogeneous distribution of geological materials. Results from sampled waters across the vadose zone reveal that the chemistry of water collected from matrix is different from that collected from fractures. In addition, analysis of heavy metals indicates that Ni is leaching across the vadose zone, and its release might be a consequence of pyrite oxidation from backfilled materials. Results obtained from VZES indicate that the combination of different techniques providing in situ quantitative and qualitative information improves conceptual models of flow and transport in a heterogeneous subsurface.

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Review and comparison of models for describing non-equilibrium and preferential flow and transport in the vadose zone

Journal of Hydrology ◽

10.1016/s0022-1694(02)00252-4 ◽

2003 ◽

Vol 272 (1-4) ◽

pp. 14-35 ◽

Cited By ~ 579

Author(s):

Jirka Šimůnek ◽

Nick J. Jarvis ◽

M.Th. van Genuchten ◽

Annemieke Gärdenäs

Keyword(s):

Vadose Zone ◽

Preferential Flow ◽

Flow And Transport ◽

Non Equilibrium

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Simulating nonequilibrium movement of water, solutes and particles using hydrus – a review of recent applications

Soil and Water Research ◽

10.17221/1200-swr ◽

2008 ◽

Vol 3 (Special Issue No. 1) ◽

pp. S42-S51 ◽

Cited By ~ 38

Author(s):

J. Šimůnek ◽

M. Köhne ◽

R. Kodešová ◽

M. Šejna

Keyword(s):

Water Flow ◽

Vadose Zone ◽

Preferential Flow ◽

Chemical Nonequilibrium ◽

Nonequilibrium Processes ◽

Modeling Tools ◽

Flow And Transport ◽

Wide Range ◽

Flow Pathways ◽

Physical And Chemical

Water and contaminants moving through the vadose zone are often subject to a large number of simultaneous physical and chemical nonequilibrium processes. Traditional modeling tools for describing flow and transport in soils either do not consider nonequilibrium processes at all, or consider them only separately. By contrast, a wide range of nonequilibrium flow and transport modeling approaches are currently available in the latest versions of the HYDRUS software packages. The formulations range from classical models simulating uniform flow and transport, to relatively traditional mobile-immobile water physical and two-site chemical nonequilibrium models, to more complex dual-permeability models that consider both physical and chemical nonequilibrium. In this paper we briefly review recent applications of the HYDRUS models that used these nonequilibrium features to simulate nonequilibrium water flow (water storage in immobile domains and/or preferential water flow in structured soils with macropores and other preferential flow pathways), and transport of solutes (pesticides and other organic compounds) and particles (colloids, bacteria and viruses) in the vadose zone.

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Isolation of Cryptosporidium parvum oocysts from fecal samples: the combination of ether extraction and discontinuous sucrose gradients

The Korean Journal of Parasitology ◽

10.3347/kjp.1994.32.1.7 ◽

1994 ◽

Vol 32 (1) ◽

pp. 7 ◽

Cited By ~ 2

Author(s):

S H Wee ◽

C G Lee ◽

B S Kim ◽

H D Joo ◽

S W Kang

Keyword(s):

Cryptosporidium Parvum ◽

Fecal Samples ◽

Ether Extraction ◽

Cryptosporidium Parvum Oocysts

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Conceptual Models of Flow and Transport in the Fractured Vadose Zone.

Vadose Zone Journal ◽

10.2136/vzj2002.2000 ◽

2002 ◽

Vol 1 (1) ◽

pp. 200-201

Author(s):

Marco Bittelli

Keyword(s):

Vadose Zone ◽

Conceptual Models ◽

Flow And Transport

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Depressed filtration ripening enhances removal of Cryptosporidium parvum

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0098 ◽

2002 ◽

Vol 2 (3) ◽

pp. 159-168 ◽

Cited By ~ 2

Author(s):

V. Gitis ◽

R.C. Haught ◽

R.M. Clark ◽

E. Radha Krishnan

Keyword(s):

Surface Water ◽

Cryptosporidium Parvum ◽

Pilot Scale ◽

Kaolin Clay ◽

Clay Particles ◽

Physico Chemical ◽

Cryptosporidium Parvum Oocysts ◽

Granular Filtration ◽

Electrostatic Adhesion ◽

Innovative Concept

Pilot-scale experiments were conducted to investigate removal of Cryptosporidium parvum by contact granular filtration. The research demonstrated enhanced removal of Cryptosporidium parvum in the presence of kaolin particles. This is believed to be due electrostatic adhesion of Cryptosporidium parvum oocysts to the kaolin clay particles. The elementary physico-chemical interactions between filter granules and suspension particles will be discussed. This innovative concept was successfully implemented to reduce the ripening sequence of subsequent filtration experimental test runs by the addition of large surface area particles to slurry of kaolin and Cryptosporidium parvum in surface water.

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Survival of giardia, cryptosporidium, poliovirus and salmonella in marine waters

Water Science & Technology ◽

10.2166/wst.1997.0744 ◽

1997 ◽

Vol 35 (11-12) ◽

pp. 261-268 ◽

Cited By ~ 30

Author(s):

D. C. Johnson ◽

C. E. Enriquez ◽

I. L. Pepper ◽

T. L. Davis ◽

C. P. Gerba ◽

...

Keyword(s):

Water Quality ◽

Salmonella Typhimurium ◽

Cryptosporidium Parvum ◽

Common Method ◽

Waterborne Pathogens ◽

Protozoan Parasites ◽

Marine Waters ◽

Untreated Sewage ◽

Cryptosporidium Parvum Oocysts ◽

Giardia Muris

Discharge of sewage into the ocean is still a common method of disposal worldwide. Both treated and untreated sewage may contain significant concentrations of waterborne pathogens, such as Giardia, Cryptosporidium, poliovirus and Salmonella. Limited studies exist on the survival of poliovirus and Salmonella in marine waters; however, almost no information exists on the survival of protozoan parasites in marine waters. This study examined the survival of Giardia muris cysts, Cryptosporidium parvum oocysts, poliovirus-1 and Salmonella typhimurium in marine waters. The survival of the microorganisms varied according to the presence of light, salinity and water quality (as determined by quantity of enterococci). All microorganisms survived longer in the dark than in sunlight, the order of survival in sunlight being: Cryptosporidium > poliovirus > Giardia > Salmonella.

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