What Chemicals are in the Drinking Water of Asutifi North District, Ghana?

Surveyed October 2024

Background

Globally, microbial drinking water quality remains a top health concern in low- and middle-income countries. There are also health risks associated with chemicals like fluoride, arsenic, and nitrates, which may be present in drinking water. Further, growing evidence indicates widespread lead contamination in drinking water supplies, often being introduced through lead-containing water system components. In Ghana, including Asutifi North District, mining operations have also significantly contributed to environmental and drinking water contamination.

The Aquaya Institute is monitoring microbial water quality over time in two districts in Ghana (see prior research briefs). In October 2024, Aquaya also tested chemical water parameters at a subset of 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 primary water points at 58 institutions, randomly selected from all public schools and healthcare facilities in the Asutifi North district. Eight (16%) were unavailable for testing due to breakdown or other reasons. We collected drinking water samples from the remaining 50 water points — 42 at schools and 8 at healthcare facilities.

Results

Parameters with low health implications

Four-fifths of samples (80%) had pH below the Ghana drinking water standard minimum value of 6.5, which may cause corrosion of metal parts in the water system. One-tenth of samples (10%) had turbidity above the standard of 5 NTU, which may reduce chlorine’s treatment effectiveness and may be visually unpleasant to water consumers. One sample (2%) had iron levels above the standard of 0.3 mg/L. 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 within the standard range.

Parameters with high health implications

We analyzed a set of chemicals (cyanide, fluoride, TON) and heavy metals (arsenic, cadmium, lead, mercury) that have known negative health impacts. Several of these may be introduced by gold mining activities in Asutifi North District, including cyanide, arsenic, cadmium, lead, and mercury. Fluoride and arsenic were included due to their recognition as priority chemicals by the international WHO/UNICEF Joint Monitoring Programme, and nitrogen was included due to its persistence in rural areas.

All samples met the Ghana drinking water standard for cyanide, fluoride, TON, arsenic, cadmium, and mercury. This implies that gold mining operations have not negatively impacted drinking water supplies at the institutions included in our sample.

Overall, 4% of samples had lead levels above the Ghana standard of 10 μg/L, or 10 parts per billion (ppb). Because of 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 in drinking water. In this brief, we define detectable lead as above 5 µg/L (ppb) due to the reporting limit of the analytical method used (ICP-MS, USEPA Method 200.8). We also report lead values above 10 ppb, which is the maximum level allowed by the Ghana Standards Authority and is the WHO provisional guideline value for lead in drinking water.

More than one-in-ten (12%) drinking water samples had detectable lead (>5 ppb) and 4% exceeded the Ghana drinking water standard limit of ppb, including 2% of school samples and 12% of healthcare facility samples. Piped system taps had more detectable lead (16%, n=31) than handpumps (5%, n=19), but no difference was observed in samples exceeding the drinking water standard of 10 ppb.

Elevated lead in drinking water was more common when pH was low. Among samples with pH below 6.5, 15% had detectable lead (>5 ppb), while no samples with pH above 6.5 had detectable lead. Low pH promotes corrosion of water system components, which can release metals into the water, including lead, if present.

Enumerators in Asutifi North conducting water quality tests on drinking water

Summary

^{This work (WaterTRACS) is supported by funding from the Conrad N. Hilton Foundation.}