HR: 0830h
AN: H51C-1052    [PDF]
TI: The Association of Cryptosporidium parvum With Suspended Sediments: Implications for Transport in Surface Waters
AU: * Searcy, K E
EM: k-searcy@northwestern.edu
AF: Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 United States
AU: Packman, A I
EM: a-packman@northwestern.edu
AF: Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 United States
AU: Atwill, E R
EM: ratwill@vmtrc.ucdavis.edu
AF: Veterinary Medicine Teaching and Research Center, School of Veterinary Medicine, University of California-Davis, 18830 Road 112, Tulare, CA 93274 United States
AU: Harter, T
EM: thharter@ucdavis.edu
AF: Department of Land, Air, and Water Resources, University of California-Davis, 125 Veihmeyer Hall, 1 Sheilds Avenue, Davis, CA 95616 United States
AB: Understanding the transport and fate of microorganisms in surface waters is of vital concern in protecting the integrity and safety of municipal water supply systems. The human pathogen Cryptosporidium parvum is a particular public health interest, as it is ubiquitous in the surface waters of the United States, it can persist for long periods in the environment, and it is difficult to disinfect in water treatment plants. Due to its small size (5 um), low specific gravity (1.05 g/cm3), and negative surface charge, C. parvum oocysts are generally considered to move through watersheds from their source to drinking water reservoirs with little attenuation. However, the transport of the oocysts in surface waters may be mediated by interactions with suspended sediments. Batch experiments were conducted to determine the extent of C. parvum oocyst attachment to several inorganic and organic sediments under varying water chemical conditions, and settling column experiments were performed to demonstrate how these associations influence the effective settling velocity of C. parvum oocysts. Results from these experiments showed that C. parvum oocysts do associate with inorganic and organic sediments and often settle at the rate of the suspended sediment. The size and surface charge of the host suspended sediment influenced the extent of oocyst attachment as oocysts preferentially associated with particles greater than 3 um, and fewer oocysts associated with particles having a highly negative surface charge. Background water chemical conditions including ionic strength, ion composition, and pH did not have a significant effect on oocyst attachment to suspended sediments.
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting