Overland and Near-surface Transport of Cryptosporidium parvum

Abstract

The use of vegetative filter strips (VFS) has been identified as a best management practice to help control the movement of agricultural pollutants into water sources. Even though VFS are effective in removing nutrients, sediments, and microorganisms from livestock runoff, the knowledge and role of VFS on pathogen transport is limiting. In this study, overland and near-surface transport of Cryptosporidium parvum (C. parvum) has been investigated in a laboratory. Effects of land slope and rainfall intensity on oocyst transport were examined using a horizontal tilting soil chamber with two compartments, bare-ground and brome vegetation. Two slope conditions (1.5 and 3.0%) were used in conjunction with rainfall intensities of 2.54 and 6.35-cm/hr for 44 minutes using a microcomputer-controlled laboratory rainfall simulator. Surface runoff and near surface flow were collected from each compartment and analyzed for total recovery of C. parvum oocysts. Results indicated that vegetation significantly reduces C. parvum concentrations compared to bare-ground for both slope conditions and rainfall intensities. Future experiments include using different soil types and a variety of vegetation with a wide range of rainfall conditions.