Aguato
    The Element Book

    Promethium

    no group (f-block) · period 6 · f-block · lanthanide

    minorPromethium has no stable isotope and no natural occurrence in water; its only water link is the fission product Pm-147 (half-life 2.62 years) from fuel reprocessing and fallout, which UK monitoring near Sellafield models in the food chain rather than measures. No guideline, no treatment role.

    Typical wastewaters

    • nuclear fuel reprocessing (Sellafield discharges) Pm-147 as Pm³⁺, a fission product in reprocessing effluent; UK monitoring models it in the food chain near Sellafield rather than measuring it no discharge quantity or effluent concentration read

    1 · Identity

    Symbol, number
    Pm, 61
    Oxidation states in water
    +3 (Pm³⁺), by analogy with neodymium and samarium; only radioactive isotopes exist
    Note
    The ion chemistry is that of a light lanthanide (book entry); in water it would follow the carbonate and phosphate speciation of the row, but no measurement of it in water was read.

    2 · Occurrence in water

    Natural sources
    None: less than a microgram per million tonnes of uranium ore as a fission product (book entry).
    Anthropogenic sources
    Pm-147 in spent fuel and reprocessing effluent and in weapons fallout. RIFE 18 lists Pm-147 (with Tc-99, Ru-106, Ce-144 and Pu-241) among the radionuclides for which concentrations in milk, meat and offal near Sellafield, the Drigg repository, Ravenglass and the Isle of Man are calculated with a simple food chain model to supplement direct measurements, where detection limits are relatively high or no measurement was made.

    3 · Speciation

    By analogy with Nd and Sm: Pm³⁺ and its carbonate complexes at neutral pH, sulfate complexes in acid water, phosphate and carbonate solids capping solubility. No aqueous measurement of promethium was read.

    Solubility
    Pm(OH)₃ and the oxalate are insoluble, PmCl₃ and Pm(NO₃)₃ soluble (book entry); no natural water data.
    Hydrolysis
    not measured in natural water
    Complexation
    not measured in natural water
    Precipitates
    Pm(OH)₃, Pm₂(C₂O₄)₃ (laboratory)

    4 · Role in treatment

    Not relevant or not given for this element.

    5 · Removal and control

    Not relevant or not given for this element.

    6 · Analytics

    methodstandarddetection limitnote
    radiometric (beta counting after radiochemical separation)as used in the RIFE programme for fission productsnot read; RIFE notes relatively high limits of detection for the modelled nuclidesPm-147 is a beta emitter, so it needs radiochemical separation before counting
    Sampling pitfalls
    None read beyond the general radiochemistry of the lanthanide fission products.

    7 · Regulatory limits

    Limits change, and many are set locally. Treat these as the published values to start from, not as your compliance target: check the standard in force at your site and the numbers written into your own permit.

    drinking water
    bodylimitnote
    US EPA National Primary Drinking Water Regulationsnot regulated no promethium entry; a beta emitter such as Pm-147 falls under the beta particle and photon emitter MCL of 4 millirem per year

    8 · Health and environmental effects

    Toxicity
    Radiological only (Pm-147, beta emitter, half-life 2.62 years in the RIFE nuclide table). No chemical toxicity data were read.
    Bioaccumulation
    not read
    Ecotoxicity
    not read

    Flags

    • The RIFE table read is a nuclide data and dose coefficient table, not a discharge inventory; no discharge quantity is written.
    • The verdict is minor on the strength of one monitoring programme entry; not relevant would also be defensible.

    Gaps

    • No measurement of Pm-147 in seawater, river water or effluent was read.
    • No Pm-147 discharge quantity from Sellafield or La Hague was read.
    • WHO GDWQ and EU DWD radioactivity provisions were not read this session.

    Sources

    The Element Book, promethium entry (data/elements/Pm.json and data/reference/text/Pm.json)
    Radioactivity in Food and the Environment, 2012 (RIFE 18), Appendix 1 CD supplement (Environment Agency, FSA, NIEA, SEPA, October 2013), section 3 and Annex table of radionuclide data
    US EPA, National Primary Drinking Water Regulations (table of regulated contaminants; no lanthanide, rare earth or actinium entry; gross alpha 15 pCi/L)

    Conventions

    Valence electrons are counted by the usual convention: the outer shell for s- and p-block elements, ns and (n-1)d for the d-block, ns, (n-1)d and (n-2)f for the f-block. Lanthanides and actinides are placed in the f-block with no group number. Electrical conductivity is the reciprocal of the printed resistivity. Ionic radii are Shannon effective radii, six-coordinate unless noted. Where a field reads “not in sources” the value was not found; it is a gap, not a zero. Regulatory limits are the published values and change often, so check the standard in force at your site and the numbers written into your own permit before you design to them.

    Data

    Element records, isotopes, radii and the descriptive text come from PubChem (NCBI), the Los Alamos National Laboratory periodic table, IUPAC CIAAW and the IAEA Atomic Mass Data Center. Appearance, thermal conductivity, electrical resistivity, crystal structure, discovery and the origin of each name come from Wikipedia and Periodic-Table-JSON, used under CC BY-SA 4.0. Hazard classifications come from the ECHA C&L inventory via PubChem. Ionic radii follow R. D. Shannon (1976). The water chapters cite their own sources at the foot of each entry, and are written to the level of Snoeyink and Jenkins, Stumm and Morgan, MWH's Water Treatment and Metcalf and Eddy.