1.Lead and selenium mainly exist in galena, clausthalite, and selenio-galena which occur as cell-filling of coal-forming plants and are of chemical-sedimentary origin.

1.铅硒主要赋存在铅矿、硒铅矿硒铅矿中，这3种矿物以植物胞腔充填现，属于化学沉积成因。