Cadmium metabolism, multi-media emissions and long-term waste burdens in China: MFA modelling, driver decomposition and sustainable management insights

Cadmium (Cd) is a toxic by-product of non-ferrous metallurgy that is intentionally used in industrial materials and low-carbon CdTe photovoltaic technologies. Existing Cd studies rarely integrate historical flow accounting, long-term waste projection and driving-factor decomposition within a unified quantitative framework, limiting the development of sustainable mitigation strategies. This study develops a national-scale Cd metabolism framework to quantify Cd flows, in-use stocks, direct releases to air and wastewater, and transfers to solid-waste management pathways in mainland China during 2010–2020, together with multi-scenario projections to 2050. Material flow analysis, logarithmic mean Divisia index decomposition, Weibull lifetime modelling and Monte Carlo uncertainty analysis are integrated to improve the reliability of the assessment. Zinc-ore by-products dominate domestic Cd inputs, while Cd consumption has shifted from nickel-cadmium batteries towards PVC heat stabilisers and CdTe photovoltaic modules. Concentrate and smelting processes are the primary sources of direct environmental releases, whereas solid-waste pathways dominate Cd transfers to waste-management systems and represent –tial long-term leakage reservoirs. Economic expansion drives continuous Cd stock accumulation, while declining material and Cd-content intensities partly offset this pressure. Scenario analysis shows that accelerated substitution with Cd-free PVC stabilisers provides the strongest source-reduction lever, substantially reducing future PVC-related Cd input, stock and end-of-life flows. CdTe lifetime extension delays retirement, accelerated photovoltaic expansion enlarges future stock and retirement burdens, and enhanced recycling increases Cd recovery while reducing residual Cd waste. By linking metal resource metabolism, environmental burdens and circular governance, this study provides a quantitative decision-support framework for life-cycle management of Cd-containing products and Cd-laden solid wastes under the low-carbon transition.