Elevated levels of rare earths from sewage plant attached to hospital complex

A preliminary ICP-MS investigation of potable and treated sewage water (TSW) showed that the rare earths were present at levels up to 20 μg/L in TSW (20 mgper ton of TSW); whilst nothing was detected in the potable water samples. A total of 12 samples were studied and the analytical performance of the ICP-MS system (detection limit 0.001 flg/L for rare earths) produced relative errors of <10% in general. TSW samples (1L each) were collected at a site fed from a hospital sewage plant. Our study showed that TSW originating from this particular source could be considered a useful source of rare earths and from this perspective our research is significant. Human waste from hospitals could contain elevated levels of rare earths, and the feasibility of extracting rare earths from TSW of this nature is discussed.