Influence of organic carbon loading, sediment associated metal oxide content and sediment grain size distributions upon Cryptosporidium parvum removal during riverbank filtration operations, Sonoma County, CA
TL;DR: Although the grain-surface metal oxides were found to have a high colloid-removal capacity, this study suggested that any major changes within the watershed that would result in long-term alterations in either the quantity and (or) the character of the river's DOC could alter the effectiveness of pathogen removal during RBF operations.
About: This article is published in Water Research.The article was published on 2010-02-01. It has received 27 citations till now. The article focuses on the topics: Dissolved organic carbon & Organic matter.
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TL;DR: In this article, a number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings, and the level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources.
Abstract: An understanding of the transport and survival of microbial pathogens (pathogens hereafter) in agricultural settings is needed to assess the risk of pathogen contamination to water and food resources, and to develop control strategies and treatment options. However, many knowledge gaps still remain in predicting the fate and transport of pathogens in runoff water, and then through the shallow vadose zone and groundwater. A number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings. The level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources. There is substantial variability in pathogen migration pathways, leading to changes in the dominant processes that control pathogen transport over different spatial and temporal scales. For example, intense rainfall events can generate runoff and preferential flow that can rapidly transport...
197 citations
Cites background from "Influence of organic carbon loading..."
...Intrinsic surface impurities of the porous medium can generate localized regions where attractive interaction is favorable even when the bulk surface has unfavorable properties (Kim et al., 2008; Metge et al., 2010)....
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...…media (Abudalo et al., 2010; Bradford et al., 2006c; Bradford et al., 2006d; Brown and Jaffé, 2001; Cao et al., 2010; Foppen et al., 2006; Guber et al., 2005a; Guber et al., 2005b; Harvey et al., 2010; Johnson and Logan, 1996; Metge et al., 2010; Pieper et al., 1997; Powelson and Mills, 2001)....
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TL;DR: The model results show that the PDFs of colloid adhesive parameters at the REA scale were sensitive to the size of the colloid and the heterogeneity, the charge and number of grid cells, and the ionic strength.
Abstract: A simple modeling approach was developed to calculate colloid adhesive parameters for chemically heteroge- neous porous media. The area of the zone of electrostatic influence between a colloid and solid−water interface (Az) was discretized into a number of equally sized grid cells to capture chemical heterogeneity within this region. These cells were divided into fractions having specific zeta potentials (e.g., negative or positive values). Mean colloid adhesive parameters such as the zeta potential, the minimum and maximum in the interaction energy, the colloid sticking efficiency (α), and the fraction of the solid surface area that contributes to colloid immobilization (Sf) were calculated for possible charge realizations within Az. The probability of a given charge realization in Az was calculated using a binomial mass distribution. Probability density functions (PDFs) for the colloid adhesive parameters on the heterogeneous surface were subsequently calculated at the representative elementary area (REA) scale for a porous medium. This approach was applied separately to the solid−water interface (SWI) and the colloid, or jointly to both the SWI and colloid. To validate the developed model, the mean and standard deviation of the interaction energy distribution on a chemically heterogeneous SWI were calculated and demonstrated to be consistent with published Monte Carlo simulation output using the computationally intensive grid surface integration technique. Our model results show that the PDFs of colloid adhesive parameters at the REA scale were sensitive to the size of the colloid and the heterogeneity, the charge and number of grid cells, and the ionic strength.
72 citations
TL;DR: A calibrated model provided a satisfactory description of the observed release behavior for a range of colloid types and sizes and a general theoretical foundation to develop predictions for the influence of solution chemistry on the transport, retention, and release of colloids.
Abstract: [1] The transport and fate of colloids, microorganisms, and nanoparticles in subsurface environments is strongly influenced by transients in solution ionic strength (IS). A sophisticated dual-permeability transport model was modified and a theory was developed to mechanistically account for the transport, retention, and release of colloids with transients in IS. In particular, colloid release in the model was directly related to the balance of applied hydrodynamic and resisting adhesive torques that determined the fraction of the solid surface area that contributed to colloid immobilization (Sf). The colloid sticking efficiency (α) and Sf were explicit functions of IS that determined the rates of colloid interaction with the solid, immobilization on the solid, colloid release from the solid and back into the bulk aqueous phase, and the maximum amount of colloid retention. The developed model was used to analyze experimental transport and release data with transients in IS for 1.1 and 0.11 μm latex microspheres, E. coli D21g, and coliphage ϕX174. Comparison of experimental values of Sf(IS) with predictions based on mean interaction energies indicated that predictions needed to account for the influence of physical and/or chemical heterogeneity on colloid immobilization. This was especially true for smaller colloids because they were more sensitive to microscopic heterogeneities that produced mainly irreversible interaction in a primary minimum and greater hysteresis in Sf(IS) with IS. Significant deviations between experimental and predicted values of α(IS) were observed for larger colloids when hydrodynamic forces were not accounted for in the predictions. A sensitivity analysis indicated that colloid release with IS transients was not diffusion controlled, but rather occurred rapidly and with low levels of dispersion. The calibrated model provided a satisfactory description of the observed release behavior for a range of colloid types and sizes and a general theoretical foundation to develop predictions for the influence of solution chemistry on the transport, retention, and release of colloids.
72 citations
Cites background from "Influence of organic carbon loading..."
...It should be mentioned that mean zeta potentials and calculated interaction energies do not account for the influence of microscopic physical and chemical heterogeneity on colloid adhesive parameters [Foppen and Schijven, 2006; Duffadar and Davis, 2007, 2008; Kim et al., 2008; Metge et al., 2010]....
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TL;DR: This review presents the four main geochemical processes relevant for inorganic geochemistry, with a focus on iron (Fe) and manganese (Mn), during bank filtration: reduction near the bank, oxidation near the production well, carbonate dissolution, and sorption to aquifer materials.
Abstract: Bank filtration induces flow of surface water through a hydraulically connected aquifer by excess pumping from a production well in the aquifer. This review presents the four main geochemical processes relevant for inorganic geochemistry, with a focus on iron (Fe) and manganese (Mn), during bank filtration: reduction near the bank, oxidation near the production well, carbonate dissolution, and sorption to aquifer materials. Physical and transport processes affect these geochemical processes and influence the redox state of the infiltrate. The presence of Fe and Mn in bank infiltrate is directly related to its redox status and can necessitate drinking water treatment after extraction. Long-term, in situ sequestration of Fe and Mn requires precipitation of oxide or carbonate solids, since a sorption front can breakthrough at the production well.
70 citations
TL;DR: In this paper, the removal of carboxylated polystyrene (PS) microspheres in a wide size range (3, 6, 25, 45, and 90μm) in two types of real surface waters (Grand River and Lake Erie water) that are sources for full-scale drinking water treatment plants was investigated.
46 citations
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TL;DR: To test the effect of geochemical heterogeneity on microorganism transport in saturated porous media, the removal of two microorganisms, the bacteriophage PRD1 and oocysts of the protozoan parasite Cryptosporidium parvum, in flow-through columns of quartz sand coated by different amounts of a ferric oxyhydroxide was measured.
Abstract: To test the effect of geochemical heterogeneity on microorganism transport in saturated porous media, we measured the removal of two microorganisms, the bacteriophage PRD1 and oocysts of the protozoan parasite Cryptosporidium parvum, in flow-through columns of quartz sand coated by different amounts of a ferric oxyhydroxide. The experiments were conducted over ranges of ferric oxyhydroxide coating fraction of lambda = 0-0.12 for PRD1 and from lambda = 0-0.32 for the oocysts at pH 5.6-5.8 and 10(-4) M ionic strength. To determine the effect of pH on the transport of the oocysts, experiments were also conducted over a pH range of 5.7-10.0 at a coating fraction of lambda = 0.04. Collision (attachment) efficiencies increased as the fraction of ferric oxyhydroxide coated quartz sand increased, from alpha = 0.0071 to 0.13 over lambda = 0-0.12 for PRD1 and from alpha = 0.059 to 0.75 over lambda = 0-0.32 for the oocysts. Increasing the pH from 5.7 to 10.0 resulted in a decrease in the oocyst collision efficiency as the pH exceeded the expected point of zero charge of the ferric oxyhydroxide coatings. The collision efficiencies correlated very well with the fraction of quartz sand coated by the ferric oxyhydroxide for PRD1 but not as well for the oocysts.
114 citations
"Influence of organic carbon loading..." refers background or methods in this paper
...…including flow rate, temperature, pH, dissolved organic compounds (Dai and Hozalski, 2002), ionic strength (Tufenkji et al., 2004), sediment grain size distribution, metal oxide content (Abudalo et al., 2005), microbe size, and both microbe and sediment surface charge (Tufenkji et al., 2004)....
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...The oocysts were harvested from a calf infected with the ‘‘Iowa’’ isolate of C. parvum (Dr. Harvey Moon, National Animal Disease Center, Ames, Iowa) and purified at the SPL before shipment to the USGS, (Boulder, CO) as described in Abudalo et al. (2005) and Harvey et al. (2008)....
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...Column experiments were conducted as detailed Abudalo et al. (2005)....
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...Other research has shown that sediment-associated metal oxide content, particularly the surface coverages of the metal oxides on the grain surfaces, is responsible for controlling virus (Pieper et al., 1997) and oocyst transport (Abudalo et al., 2005) in iron-laden quartz sand....
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TL;DR: In this paper, the authors examined the non-perturbed deposition and re-entrainment dynamics of biological and non-biological colloids in porous media in the presence of an energy barrier to deposition at the grain surface.
108 citations
TL;DR: It is demonstrated that seasonal ground water temperatures monitored in observation wells provide an effective means of estimating hydraulic conductivities in alluvial aquifers.
Abstract: Well water temperatures are often collected simultaneously with water levels; however, temperature data are generally considered only as a water quality parameter and are not utilized as an environmental tracer. In this paper, water levels and seasonal temperatures are used to estimate hydraulic conductivities in a stream-aquifer system. To demonstrate this method, temperatures and water levels are analyzed from six observation wells along an example study site, the Russian River in Sonoma County, California. The range in seasonal ground water temperatures in these wells varied from <0.2 degrees C in two wells to approximately 8 degrees C in the other four wells from June to October 2000. The temperature probes in the six wells are located at depths between 3.5 and 7.1 m relative to the river channel. Hydraulic conductivities are estimated by matching simulated ground water temperatures to the observed ground water temperatures. An anisotropy of 5 (horizontal to vertical hydraulic conductivity) generally gives the best fit to the observed temperatures. Estimated conductivities vary over an order of magnitude in the six locations analyzed. In some locations, a change in the observed temperature profile occurred during the study, most likely due to deposition of fine-grained sediment and organic matter plugging the streambed. A reasonable fit to this change in the temperature profile is obtained by decreasing the hydraulic conductivity in the simulations. This study demonstrates that seasonal ground water temperatures monitored in observation wells provide an effective means of estimating hydraulic conductivities in alluvial aquifers.
99 citations
"Influence of organic carbon loading..." refers methods or result in this paper
...…are only estimates, our estimates of K (3.4 10 4 to 8.8 10 6 m s 1) were consistent with values reported for the Russian River site in previous studies, e.g., from 5.5 10 5 to 2.0 10 4 m s 1 (Su et al., 2004), 4.17 10 4 m s 1 (Constantz et al., 2006) and 1.4 10 5 to 2.6 10 4 m s 1 (Gorman, 2004)....
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...Measured hydraulic conductivities for the shallow aquifer sediments site range from 5.5 10 5 to 2.0 10 4 m s 1 (Su et al., 2004) and from 1.4 10 5 to 2.6 10 4 m s 1 within the same area using seepage meter techniques (Gorman, 2004)....
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...These estimations were compared with estimates from previous aquifer tests (Su et al., 2004; Gorman, 2004)....
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TL;DR: Comparisons of zeta potential, hydrophobicity, and filterability of a surrogate particle, 5 microm carboxylated latex microspheres, and oocysts in filtration and particle transport experiments suggest that micro Spheres can be used to provide a conservative estimate of oocyst removal in filters containing hydrophilic negatively charged filter media.
Abstract: The size and surface characteristics of a surrogate particle and Cryptosporidium parvum oocysts are important in determining the ability of the particle to mimic the behavior of C. parvum oocysts in filtration and particle transport experiments. The ζ potential, hydrophobicity, and filterability of a surrogate particle, 5 μm carboxylated latex microspheres, and oocysts were compared for a variety of solution conditions. C. parvum oocysts had a slightly negative ζ potential (−1.5 to −12.5 mV) at pH 6.7 over a wide range of calcium concentration (10-6−10-1 M), while the fluorescent microspheres were more negatively charged under the same conditions (−7.4 to −50.2 mV). After exposure to 5 mg of C/L of Suwanee River natural organic matter (NOM), the ζ potentials of both particles became significantly more negative, with the microspheres consistently maintaining a more negative ζ potential than the oocysts. Alum was able to neutralize the negative ζ potentials of both particles when in the presence of NOM, but...
89 citations
"Influence of organic carbon loading..." refers background in this paper
...Finally, microspheres, evaluated as surrogates for oocysts in filtration and transport experiments, provided conservative estimates of oocyst removal in water treatment filters (Dai and Hozalski, 2003)....
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TL;DR: Results show that adhesion properties governed by the electrophoretic mobility of purified C. parvum oocysts can be altered by the method of purification and that hydrophobicity can change as oocyst age.
Abstract: The protozoan parasite Cryptosporidium parvum has been responsible for several recent waterborne disease outbreaks in the United States (26, 31). This gastrointestinal illness is transmitted by an environmentally durable oocyst (15). C. parvum oocysts have been identified in significant amounts in surface waters throughout the United States and Canada (27, 34, 38). Public drinking water supplies derived from filtered surface waters were implicated in all U.S. waterborne cryptosporidiosis outbreaks between 1984 and 1993 (10). Filtration is an important barrier in drinking water purification, because C. parvum oocysts are highly resistant to disinfection with chlorine (25).
Recent studies suggest that the surface properties of C. parvum oocysts may differ from those of bacteria and other microbes. Results reported by Fogel et al. (16) suggest that significant numbers of C. parvum oocysts bypassed a filtration plant that retained smaller coliform bacteria, indicating that oocysts may not adhere to filter media as readily as other microbes. In a series of microscope studies, Anguish and Ghiorse (2) reported that C. parvum oocysts seeded into soil samples and suspended in deionized water (DI), phosphate-buffered saline (PBS), or 0.1% sodium pyrophosphate did not closely associate with inorganic or organic soil particles.
The surface properties of the oocyst wall affect the interactions of the oocysts with filter media and with environmental chemicals and surfaces. Changes in the oocyst wall as they age may affect the adhesion and transport properties of oocysts in natural environments. Changes in the oocyst wall may also affect oocyst survival. For example, Robertson et al. (37) noted that when oocysts were stored in fecal material, the oocyst wall permeability of potentially viable oocysts decreased over time.
Net surface charge and hydrophobicity are important factors mediating microbial adhesion to surfaces (21, 46). Understanding the surface charge and hydrophobicity of C. parvum oocysts will aid the development of optimum filtration media and coagulants to remove oocysts from drinking water and sewage in treatment plants. Such basic knowledge will also help clarify the microscale processes involved in sorption of oocysts onto particle surfaces in natural waters. The identification of noninfective surrogates with similar surface properties will also help facilitate development of treatment strategies and laboratory transport experiments.
Surface charge measurements for C. parvum oocysts have recently been reported by Ongerth and Pecoraro (33), Drozd and Schwartzbrod (14), and Rice et al. (36). Each of these studies utilized different oocyst sources, purification methods, storage solutions, and suspending media, and the reported results varied widely. Some chemicals used for oocyst purification in these studies may damage the oocysts (9) and change oocyst surface properties, including surface charge. A survey of the literature reveals few if any studies of electrophoretic mobilities for C. parvum oocysts in which oocysts were purified and stored under controlled conditions with concern about the use of surface-active chemicals.
Microbial adhesion to hydrophobic surfaces such as polystyrene can be used as a surrogate measurement of microbial adhesion to organic material in the soil. We developed a method for estimating oocyst hydrophobicity that relied on microscopic direct counting of suspended oocyst concentrations after adhesion to a standard polystyrene surface (40, 45, 46). This method was used to measure oocyst hydrophobicity as a function of the ionic strength of the suspending solution. Polystyrene was an ideal substrate for these tests because it is very hydrophobic (1), and the percentage of particles adhering to the polystyrene substrate under the mixing action of a micropipettor provided a reliable qualitative measure of the particle-surface adhesion energy (43, 48).
The objectives of this study were to estimate the electrophoretic mobility of C. parvum oocysts and to determine the effects of purification method and presence of antibiotics on the electrophoretic mobility. We also measured the effects of solution ionic strength on the hydrophobicity of oocysts and polystyrene beads and determined how the electrophoretic mobility and hydrophobic properties of oocysts change as they age.
76 citations
"Influence of organic carbon loading..." refers background in this paper
...Although carboxylated microspheres may be obtained that have similar buoyant densities, sizes, and aspect ratios to those of oocysts (Harvey et al., 2008), the electrophoretic mobilities can differ, depending upon the pH, age, and treatment of the oocysts (Brush et al., 1998; Butkus et al., 2003)....
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