[Ionogenic liberation of mercury from dental amalgam in waste water and sludge]

Reduction of mercury content in communal waste water and sludge is mandatory. The release rate of Hg from dental amalgam (gamma 2 Lux Alloy) in waste water was determined. The Hg-ionic rate was found to be as low as 0.004% of total mercury content in waste water. In addition, the concentration of Hg (4.39-8.20 mg/kg), Ag (73.35-84.03 mg/kg and Sn (22.51-61.30 mg/kg) in sludge was estimated under anaerobic conditions. Compared with legal limits for drinking water (1 microgram Hg/l) in the F.R.G. mercury loads of dental surgeries are far below threshold levels where toxicological effects are to be expected.