Metal Usage in Modern Technology (IMAGE) Yale School of the Environment Caption Modern technology relies on virtually all of the stable elements of the periodic table. This figure, which pictures the concentrations (in parts per million) of elements on a printed circuit board, provides an illustration of that fact. The concentrations of copper and iron are obviously the highest, and others such as cesium are much lower, but concentration clearly does not reflect elemental importance: all the elements are required in order to maintain the functions for which the board was designed. Credit Thomas Graedel, et al Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.