Past and future cadmium emissions from municipal solid-waste incinerators in Japan for the assessment of cadmium control policy.

Cadmium (Cd) is a harmful pollutant emitted from municipal solid-waste incinerators (MSWIs). Cd stack emissions from MSWIs have been estimated between 1970 and 2030 in Japan. The aims of this study are to quantify emitted Cd by category and to analyze Cd control policies to reduce emissions. Emissions were estimated using a dynamic substance flow analysis (SFA) that took into account representative waste treatment flows and historical changes in emission factors. This work revealed that the emissions peaked in 1973 (11.1t) and were ten times those in 2010 (1.2 t). Emission from MSWIs was two-thirds of that from non-ferrous smelting in 2010. The main Cd emission source was pigment use in the 1970s, but after 2000 it had shifted to nickel-cadmium (Ni-Cd) batteries. Future emissions were estimated for 2030. Compared to the business-as-usual scenario, an intensive collection of used Ni-Cd batteries and a ban on any future use of Ni-Cd batteries will reduce emissions by 0.09 and 0.3 1t, respectively, in 2030. This approach enables us to identify the major Cd emission source from MSWIs, and to prioritize the possible Cd control policies.