Identification and treatment of lithium as the primary toxicant in a groundwater treatment facility effluent

摘要

sup 6 Li is used in manufacturing nuclear weapons, shielding, and reactor control rods. Li compounds have been used at DOE facilities and Li-contaminated waste has historically been land disposed. Seep water from burial grounds near Y-12 contain small amounts of chlorinated hydrocarbons, traces of PCBs, and 10-19 mg/L Li. Seep treatment consists of oil-water separation, filtration, air stripping, and carbon adsorption. Routine biomonitoring tests using fathead minnows and (ital Ceriodaphnia)(ital dubia) are conducted. Evaluation of suspected contaminants revealed that toxicity was most likely due to Li. Laboratory tests showed that 1 mg Li/L reduced the survival of both species; 0.5 mg Li/L reduced (ital Ceriodaphnia) reproduction and minnow growth. However, the toxicity was greatly reduced in presence of sodium (up to 4 mg Li/L, Na can fully negate the toxic effect of Li). Because of the low Na level discharged from the treatment facility, Li removal from the ground water was desired. SuperLig(reg sign) columns were used (Li-selective organic macrocycle bonded to silica gel). Bench-scale tests showed that the material was very effective for removing Li from the effluent, reducing the toxicity.