2007 Ground Water Summit

Wednesday, May 2, 2007 : 1:40 p.m.

Bacterial Quality and Potential Treatment of Ground Water in a Rural Region of the Eastern Cape Province, South Africa

Walton R. Kelly, Ph.D., Illinois State Water Survey

Many residents of the Eastern Cape Province, the poorest province of South Africa, rely on groundwater. A total of 33 sites were sampled in the south-central part of the province to examine the bacterial quality of the water supplies. Samples were collected four times between 2004 and 2006 from boreholes, storage reservoirs, and taps. Total coliforms were detected in almost all the samples, with a high value of 300 cfu/mL. Twenty of 29 boreholes that were sampled had detectable E. coli at least once, and 11 boreholes had detectable E. coli every time they were sampled. Ten of 12 reservoirs and 9 of 14 taps had detectable E. coli during at least one sampling event. Two boreholes, five reservoirs, and one tap had detectable Salmonella at least once. Vibrio was never detected. In cases where both a borehole and a reservoir or tap were sampled at a site, the concentrations of total coliform and E. coli were always greater in the reservoir or tap. This may be due to additional sources of contamination to the reservoirs such as bird feces, or because biofilms have formed in the distribution system. Bacterial occurrence does not appear to be correlated with any chemical parameters. Borehole protection practices were absent at almost all sites; livestock were allowed to graze up to the wellhead and in many villages outdoor privies were located up-gradient from the boreholes. Continuing research is focused on evaluating a relatively inexpensive, easy-to-use method of sanitization, a silver bactericide filter material developed in the Department of Materials Science at the University of Illinois. This product is attractive because it requires no electricity, chemical handling, or specialized training, and can be regenerated numerous times by simply heating for a short period.

Walton R. Kelly, Ph.D., Illinois State Water Survey Walt Kelly is a groundwater geochemist at the Illinois State Water Survey, primarily studying anthropogenic and natural contaminants in groundwater, including nitrogen, arsenic, chloride, heavy metals, and pathogenic bacteria. He received a Ph.D. in Environmental Sciences from the University of Virginia in 1993, and a M.S. in Geological Sciences from Case Western Reserve University in 1984. He was previously employed by the U.S. Nuclear Regulatory Commission in the nuclear waste program in the 1980s.


The 2007 Ground Water Summit