MEASUREMENTS Preserving metal samples The accurate analysis of trace metal concentrations is critical to monitoring and controlling drinking-water quality because some metals have an adverse environmental and medical impact, and the allowable concentrations in drinking water have been decreasing. J. T. Creed, T. D. Martin, and M. Sivaganesan investigated the effects of pH, sample container batch, and water matrices on trace metal analysis in drinking water. Different batches of a low-density polyethylene blend sample container were analyzed by inductively coupled plasma-mass spectrometry to study a representative array of metals important to drinking-water quality. Drinking-water samples from throughout the United States were compared. Sample metal concentrations were not affected by the container batch, and metals leaching from containers with acidified samples were not significant. Acidification of samples to a pH
