February 2025
What Chemicals are in the Drinking Water of Kabarole District, Uganda?
Surveyed February 2024
Background
Globally, microbial drinking water quality remains a top health concern in low- and middle-income countries. Chemicals like fluoride, arsenic, and nitrates, which may be present in drinking water, also pose health risks. Heavy metals in the water in Kabarole, including lead, mercury, and cadmium, are also a growing concern, with evidence of widespread lead contamination in drinking water supplies—often introduced through lead-containing pipes and infrastructure.
The Aquaya Institute is monitoring microbial water quality over time in two districts in Uganda (see prior research briefs). In February 2024, Aquaya also tested chemical water parameters at several water points to get a more comprehensive picture of water quality, including contaminants with known health risks and physiochemical parameters affecting user acceptability.
Aquaya visited 73 institutions, randomly selected among all public schools and healthcare facilities in Kabarole district. We identified 126 drinking water points at these institutions, including both primary and secondary sources. Twenty (16%) were unavailable for testing due to breakdowns or other reasons. We collected water samples from the remaining 106 water points—74 at schools and 32 at healthcare facilities.
Enumerators in Kabarole are conducting water quality tests on drinking water
Results
Parameters with low health implications
A third of the samples (34%) had a pH below the Uganda National Bureau of Standards (UNBS) drinking water standard minimum value of 6.5, which may cause corrosion of metal parts in the water system. Two-fifths of samples (40%) had turbidity above the standard of 5 NTU, which may reduce chlorine’s treatment effectiveness and be visually unpleasant to water consumers. One-fifth of the samples (22%) had iron levels above the 0.3 mg/L standard. Elevated iron does not represent a known health risk, but water consumers may not like the water’s taste or appearance. All samples had electrical conductivity, chloride, total hardness, phosphate, and sulfate within the standard range.
Parameters with high health implications
We analyzed a set of chemicals (fluoride, nitrate-N, and nitrite-N) and heavy metals (arsenic and lead) that have known negative health impacts. Fluoride and arsenic were included due to their recognition as priority chemicals by the international WHO/UNICEF Joint Monitoring Programme, nitrogen was included due to its persistence in rural areas, and lead was included due to national and global interest to reduce lead exposure from drinking water.
All samples met the UNBS drinking water standard for fluoride. Over half (56%) of samples had nitrite above the UNBS standard of 3 μg/L; however, there were no nitrite exceedances with respect to the WHO guideline value of 900 μg/L. Few samples had nitrate (2%) and arsenic (3%) concentrations above UNBS standards.
Overall, 9% of samples had detectable lead levels above 15 μg/L or 15 parts per billion (ppb). Due to its health impacts, we include more information about lead in the following section.
Spotlight: Lead in drinking water
In some cases, lead is present in drinking water from naturally-occurring sources. However, in most cases, lead contamination in drinking water comes from lead-containing components in water systems, such as pipes, faucets, and plumbing fixtures. Exposure to lead in drinking water may lead to negative neurodevelopment effects, with infants and children being most vulnerable.
There is no safe level of lead contamination in drinking water. In this brief, we define detectable lead as above 15 µg/L (ppb) due to the reporting limit of the analytical method used (ICP-OES, USEPA Method 200.2). This is less conservative than the maximum level allowed by the UNBS drinking water standard and the WHO provisional guideline value of 10 ppb. In other words, more samples may exceed the 10 ppb standard than the percentage reported here that exceeds the 15 ppb level.
One-tenth (9%) of drinking water samples had detectable lead (≥15 ppb), including 7% of school samples and 13% of healthcare facility samples. Handpump samples had more detectable lead (29%, n=7) than piped system taps (9%, n=23) (Figure 1), though relatively small sample sizes limit robust comparisons.
Elevated lead in drinking water was more common when pH was low. Among samples with pH below 6.5, 20% (n=15) had detectable lead (≥15 ppb), compared to only 3% of samples with pH above 6.5 (n=30). Low pH promotes corrosion of water system components, which can release metals into the water, including lead, if present.
Random daytime Samples, Kabarole: Lead concentrations by water point type. Water samples were collected from a subset of institutional water points in Kabarole District.
Summary
- We tested water quality parameters at water points from a sample of schools and healthcare facilities.
- Some water points exceeded drinking water standards for parameters with low health implications, like pH, turbidity, and iron. These parameters do not directly affect health but may be unpleasant to users and can interfere with treatment efforts.
- Among parameters with high health implications, some water points exceeded drinking water standards for nitrite, nitrate, arsenic, and lead. All samples met drinking water standards for fluoride.
- Lead levels exceeded drinking water standards in one-tenth of samples, which may have severe health implications.
This work (WaterTRACS) is supported by funding from the Conrad N. Hilton Foundation.
