Q.(a) Explain the methods of disposal of radioactive wastes. OR

(a) Radioactive waste is managed through shielded storage, vitrification and deep geological burial (with ocean disposal now largely discontinued). (b) Biodiversity is lost mainly through habitat destruction, over-exploitation, invasive species, co-extinction, and pollution/climate change ('the evil quartet' plus related pressures).

(a) Because radioactive waste remains hazardous for very long half-lives, its disposal requires long-term containment away from living organisms. Low- and intermediate-level waste is often stored in secure, shielded containers/casks at generating facilities to allow short-lived radioactivity to decay before further handling. High-level waste is frequently vitrified -- fused with glass-forming materials into a stable glass or ceramic block -- which locks the radioactive elements into a solid matrix highly resistant to leaching, before being placed in corrosion-resistant canisters. The vitrified/contained waste is then typically disposed of by deep geological disposal: burial in stable, impermeable rock formations (such as deep salt beds, granite, or clay) hundreds of metres underground, chosen for their geological stability and isolation from groundwater and the biosphere over the very long timescales required. Ocean/deep-sea-bed disposal in sealed drums was practised in the past but is now largely banned or restricted under international agreements because of the difficulty of guaranteeing long-term containment and the risk to marine ecosystems. …