Sorption of Cryptosporidium parvum oocysts (C. parvum) From
Water by Nanoparticles
Background
Cryptosporidium pcirvum (C. parvum) is an obligate enteric protozoan parasite released into the environment by
feces of infected human and animals. The environmental resistant form of 'Cryptosporidium parvum parasites is the
oocyst. These organisms pose threats to human health and ecological systems. Among the water microbial
contaminants commonly found in nature, C. parvum oocysts are of significant concern in United States and
elsewhere. Transmissive oocysts are difficult to treat and highly resistant to low levels of conventional disinfection
chemicals and inactivation methods compared to most microorganisms. Concern about C. parvum oocysts transport
in surface water has prompted a need for water quality criteria to protect animals and humans from adverse effects
of C. parvum oocysts contamination.
Objectives
• Using batch equilibration methods, study sorption of Cryptosporidium parvum oocysts to nanoparticles
from water to better understand the sorption mechanisms responsible for fate and transport in soils
• Using equilibrated batch methods, evaluate the effect pH and ionic strength of solution on the sorption of
oocysts to nanoparticles and desorption/release of oocyst from nanoparticles in water
• Using a zeta potential meter, study the effect of pH and ionic composition of solution on both C. parvum
oocyst and nanoparticles zeta potential (surface charges)
Approach
Researchers use a wide array of state-of-the-science instruments and test innovative techniques specific to collected
nanoparticles and microbial interaction data in order to support EPA's mission. This research project focuses on the
use of various types of manufacture-engineered nanomaterials to remediate water pathogens (Cryptosporidium
parvum oocysts) from suspension. A central goal of this project involves the evaluation of the effects of pH and
different ionic strengths of aqueous solution on the stability of C. parvum oocysts and nanoparticles in water.
For bench-top studies, scientists conducted sorption batch equilibrated experiments with ('. parvum oocysts and
positive-charged nanoparticles in water for the purpose of understanding their fate and transport in natural soil and
water ecosystems. To leverage technical expertise, this project is being coordinated with in-house research
scientists, with a proposed collaborative scientist in EPA's National Risk Management Research Laboratory, and
with researchers from Michigan State University.
Accomplishments
All experimental results of this project will be available in technical reports, posters, or oral presentations. Journal
articles are under preparation.
Selected Publications
Roberts, M.G., J. Griffitts, B. Faulkner, C. Su, M. Ware, J. Groves, and J. Ferguson. (Under preparation). "The
Effects of Geochemical Processes on the Stability of Suspended Cryptosporidium parvum Oocysts and Copper (II)
Oxide Nanoparticles in Water."
The National Risk Management Research Laboratory's mission is to advance scientific and engineering
solutions that enable EPA and others to effectively manage current and future environmental risks.
NRMRL possesses unique strengths and capabilities and is dedicated to providing credible
technological information and scientific solutions that support national priorities
and protect human health and the environment.
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Non-Refereed Publications/Presentations
Ferguson, J. and M.G. Roberts. (2009). "The Effects of pH on the Stability of Cryptosporidium pctrvum Oocysts
and Copper (II) Oxide Nanoparticles in Water." Presentation, 2009 Annual Meeting of The McNair Internship
Program, East Central University, Ada, Oklahoma, April 29.
The National Risk Management Research Laboratory's mission is to advance scientific and engineering
solutions that enable EPA and others to effectively manage current and future environmental risks.
NRMRL possesses unique strengths and capabilities and is dedicated to providing credible
technological information and scientific solutions that support national priorities
and protect human health and the environment.
Investigators
Dr. Michael Roberts
Ground Water and Ecosystem Restoration Division
Ada, Oklahoma 74820
580-436-8558
Proposed Collaborators
Michigan State University
Michael Ware
U.S. EPA, National Risk Management Research
Laboratory
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