RESUMO
Lusaka, Zambia, is a rapidly growing city located on a vulnerable karstic dolomite aquifer that provides most of the city's drinking water. Over 65% of residents live in peri-urban communities with inadequate sanitation leading to widespread groundwater contamination and the spread of waterborne diseases such as cholera. To fill the water service gap, Water Trusts were created: public/private partnerships designed to provide clean water to peri-urban community residents. Water Trusts extract groundwater via boreholes, treat it with chlorine, and distribute it to residents via public kiosks. We investigated the efficacy of drinking water provision to residents in six of Lusaka's peri-urban communities with Water Trusts. Water samples were collected from Water Trust boreholes and kiosks, privately owned boreholes, and shallow wells during four sampling efforts. To assess potential risk to human health, water samples were analyzed for Escherichia coli (E. coli) and nitrate. Shallow wells were significantly more contaminated with E. coli than Water Trust boreholes, kiosks, and private boreholes (Tukey-adjusted p values of 9.9 × 10-6). Shallow wells and private boreholes had significantly higher nitrate-N concentrations (mean of 29.6 mg/L) than the Water Trust boreholes and kiosks (mean of 8.8 mg/L) (p value = 1.1 × 10-4). In 2016, a questionnaire was distributed to Water Trust managers to assess their ability to meet demands. In the six communities studied, Water Trusts served only about 60% of their residents. Water Trusts provide a much safer alternative to shallow wells with respect to nitrate and E. coli, but they struggle to keep pace with growing demand.