Mobile phones and various electronic products contribute to the world's fastest-growing category of hazardous waste with international repercussions. We investigated the trends in potential human health impacts and ecotoxicity of waste mobile phones through quantitative life cycle impact assessment (LCIA) methods and regulatory total threshold limit concentrations. A market-dominant sample of waste basic phones and smartphones manufactured between 2001 and 2015, were analyzed for toxicity trends based on 19 chemicals. The results of the LCIA (using USEtox model) show an increase in the relative mass of toxic materials over the 15-year period. We found no significant changes in the use of toxic components in basic phones, whereas smartphones contained a statistically significant increase in the content of toxic materials from 2006 to 2015. Nickel contributed the largest risk for carcinogens in mobile phones, but the contributions of lead and beryllium were also notable. Silver, zinc and copper contents were associated with non-cancer health risks. Copper components at 45,818-77,938 PAF m³/kg dominated ecotoxicity risks in mobile phones. Overall, these results highlight the increasing importance of monitoring trends in materials use for electronic product manufacturing and electronic-waste management processes that should prevent human and environmental exposures to toxic components.

Cement plays a dual role in the global carbon cycle like a sponge: its massive production contributes significantly to present-day global anthropogenic CO2 emissions, yet its hydrated products gradually reabsorb substantial amounts of atmospheric CO2 (carbonation) in the future. The role of this sponge effect along the cement cycle (including production, use, and demolition) in carbon emissions mitigation, however, remains hitherto unexplored. Here, we quantify the effects of demand- and supply-side mitigation measures considering this material-energy-emissions-uptake nexus, finding that climate goals would be imperiled if the growth of cement stocks continues. Future reabsorption of CO2 will be significant (~30% of cumulative CO2 emissions from 2015 to 2100), but climate goal compliant net CO2 emissions reduction along the global cement cycle will require both radical technology advancements (e.g., carbon capture and storage) and widespread deployment of material efficiency measures, which go beyond those envisaged in current technology roadmaps.