Levels of trace metals in Riyadh drinking water at the consumer taps

Abstract

Three hundred and twenty water samples were collected from 40 homes in the city of Riyadh and analyzed to evaluate the levels of trace metals iron, copper, chromium, lead, zinc and cadmium and to examine any possible correlations with plumbing type, age, and water characteristics. The mean and peak concentrations of the trace metals were compared to health and/or aesthetic guideline values given by the Saudi Arabian Standards Organization (SASO). The study revealed that 88% of the homes studied utilize galvanized iron plumbing, whereas, PVC and copper plumbings are used in 10 and 2%, respectively. Homes with galvanized iron plumbing showed higher levels of trace metals than those with PVC and copper plumbings. The optimum standard for iron as specified by SASO was exceeded in 34% of the samples, while that for copper was exceeded in 23% of the samples. Only 3% of the samples exceeded the maximum standard for lead, and none of the samples exceeded the chromium, zinc and cadmium optimum/maximum standards. The analyses concluded that a positive correlation exists between water characteristics and trace metals levels and that the elevated levels of metals were the result of corrosion and leaching from both the distribution network and in-house plumbing.