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Determination of the speciation and bioavailability of samarium to Chlamydomonas reinhardtii in the presence of natural organic matter
Author(s) -
Rowell JustineAnne,
Fillion MarcAlexandre,
Smith Scott,
Wilkinson Kevin J.
Publication year - 2018
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.4106
Subject(s) - chemistry , bioavailability , environmental chemistry , dissolved organic carbon , organic matter , genetic algorithm , chlamydomonas reinhardtii , samarium , inorganic chemistry , organic chemistry , ecology , bioinformatics , biochemistry , gene , mutant , biology
Abstract As technological interest and environmental emissions of the rare earth elements increase, it is becoming more important to assess their potential environmental impact. Samarium (Sm) is a lanthanide of intermediate molar mass that is used in numerous high‐technology applications including wind turbines, solar panels, and electric vehicles. The present study relates the speciation of Sm determined in the presence of natural organic matter (NOM) to its bioavailability to the unicellular green alga Chlamydomonas reinhardtii . The free ion concentration was determined using a cation exchange resin (ion exchange technique) in dynamic mode and compared with thermodynamic modeling. Short‐term biouptake experiments were performed in the presence of 4 types of NOM: Suwannee River fulvic acids, Pahokee Peat fulvic acids, Suwannee River humic acids, and a Luther Marsh dissolved organic matter isolate (90–95% humic acids). It was clearly shown that even a small amount of NOM (0.5 mg C L −1 ) resulted in a significant decrease (10 times) in the Sm internalization fluxes. Furthermore, complexation with humic acids (and the corresponding reduction in Sm bioavailability) was stronger than that with fulvic acids. The results showed that the experimentally measured (free) Sm was a better predictor of Sm internalization than either the total concentrations or the free ion concentrations obtained using thermodynamic modeling. Environ Toxicol Chem 2018;37:1623–1631. © 2018 SETAC