Risks related to the critical nature of arsenic -- used to make high-speed computer chips that contain gallium arsenide -- outstrip those of other substances in a group of critical materials needed to sustain modern technology, a new study has found. Scientists evaluated the relative criticality of arsenic and five related metals in a report in the ACS' journal Environmental Science & Technology.
T. E. Graedel, E. M. Harper, N. Nassar and colleagues explain that five metals -- gold, silver, arsenic, selenium and tellurium -- exist in small amounts within larger deposits of copper. Supplies of all six elements are critically important for modern technology. Copper wires, for instance, conduct electricity; electronics makers rely on gold and silver; solar panels require selenium and tellurium and computer chips contain arsenic. The research group notes that while a shortage of any of these would hurt a range of technology industries, there is no existing standard for assessing the relative supply risk, environmental concerns and vulnerability to supply restriction of the metals.
To fill that gap, the team explored the so-called "criticality" of these six metals, a term that takes into account the risk of future scarcity and the potential damage from shortages. They found arsenic to be the most critical, with silver and selenium close behind. The rankings are dynamic and will evolve over time, the scientists note, because the underlying factors that determine criticality for arsenic and the other elements vary with changing economic, technological and social conditions. Using the group's methodology, corporations and nations could identify their unique set of critical materials and take concrete steps to stabilize their supply chains, as well as identify and improve the performance of less critical substitute materials.
- Nedal T. Nassar, Rachel Barr, Matthew Browning, Zhouwei Diao, Elizabeth Friedlander, E. M. Harper, Claire Henly, Goksin Kavlak, Sameer Kwatra, Christine Jun, Simon Warren, Man-Yu Yang, T. E. Graedel. Criticality of the Geological Copper Family. Environmental Science & Technology, 2012; 46 (2): 1071 DOI: 10.1021/es203535w
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