Maximum, minimum and typical concentration of copper, iron, lead and zinc that can be leached in tap water

Lead, copper and iron are the contaminants whose concentrations are most likely to exceed the recommended values ​​due to the corrosion of drinking water distribution system materials. This work studies the maximum, minimum and typical concentration of copper, iron, lead and zinc that can be leached in public tap water in Niamey (Niger). Thus, water samples were taken at the outlet of twelve taps after water stagnation for six hours and after water stagnation for six hours followed by a five-minute drain at maximum flow. For the evaluation of typical concentrations, two half-liters of water are sampled randomly during the day without stagnation or prior emptying. The samples of the first liters taken after a stagnation of 6 hours are more concentrated in metals (from 1 to 12 times) than the samples taken after a draining of 5 minutes. Concentrations of iron and lead generally exceed WHO guideline values. The evaluation of the typical concentration of Cu, Fe, Pb and Zn showed that 91.66% and 16.66% of the analyzed samples exceeded the respective guide values ​​for Pb and Fe. The typical concentrations of Zn and Cu in water taken from the same taps are in line with WHO guideline values.