Concentrations of Trace Elements in Daily Life Water Consumed in Angono, Rizal, Philippines
Objective. The present study aims to determine the concentrations of seven trace elements [chromium (Cr), arsenic (As), cadmium (Cd), cesium (Cs), lead (Pb), thorium (Th), and uranium (U)] in tap, well, spring, river, and lake waters in the town of Angono, Rizal in the Philippines, consumed for drinking, cooking, bathing, and washing. In the town of Angono, both of the tap and purified tap waters produced in the refilling station are consumed as the water for drinking.
Methods. Water samples from six unpurified tap, six purified taps, 10 wells, two springs, two rivers, and one lake water were obtained in October 2015. Samples were analyzed using solution nebulization inductively coupled plasma mass spectrometry. Results were evaluated for health risks of the trace elements in the water samples using WHO guideline values. The provisional WHO guideline values are as follows: Cr: 50 µg/L, As: 10 µg/L, Cd: 3 µg/L, Pb: 10 µg/L, and U: 30 µg/L. That of Cs has not been proposed yet. The WHO guideline value for the naturally occurring radioactive isotope 232Th in drinking water is 1 Bq/L, which is equivalent to 250 μg/L.
Results. The concentrations of the trace elements in the tap water samples were <0.5% of the WHO guideline values, except Cs and Cd, with those of Cd being ~9% of the WHO guideline value. Purified tap waters contained the seven trace elements in lower concentrations, with the exception of Pb, which may have been added in small amounts from equipment used for water purification. The concentrations of the trace elements in water samples from the wells and springs in Angono were more variable than those of the tap waters, and these were also below the WHO guideline values. The concentrations of Cs in all water samples were <0.3 µg/L. The trace-element concentrations of the waters from Angono River and Laguna Lake were almost the same as those of the well and spring waters.
Conclusion. At present, the concentrations of trace elements in daily life water consumed in Angono are at safe levels.