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Doped rare earth oxides and their constituent metals inhibit Raphidocelis subcapitata growth via ion leaching, nutrient removal and agglomeration

Сведения об участнике
ФИО
Elise Joonas
ФИО (на английском языке)
Elise Joonas
Название организации
National Institute of Chemical Physics and Biophysics
Информация о докладе
Вид доклада
Постерный доклад
Секция
Биотестирование в нормировании и токсикологическом контроле
Название доклада
Doped rare earth oxides and their constituent metals inhibit Raphidocelis subcapitata growth via ion leaching, nutrient removal and agglomeration
Соавторы доклада (ФИО, организация, город, страна)
Villem Aruoja (National Institute of Chemical Physics and Biophysics, Tallinn, Estonia), Kalle Olli (Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia), Anne Kahru (National Institute of Chemical Physics and Biophysics,Tallinn, Estonia)
Аннотация
Rare earth elements (REEs) are increasingly used in diverse applications, including electronics, renewable energy, and medicine, posing an environmental hazard via various waste streams. We studied the potential toxic impact of nine doped REE oxides (d-REOs) and the corresponding soluble metal salts on the algae Raphidocelis subcapitata (OECD 201 test).
Tentative EC50 (72 h, mg oxide l⁻¹) values for the d-REOs varied from toxic to not harmful: Ce0,8Pr0,2O2, CeO2, (La0,6Sr0,4)0,95CoO3 and La2NiO4 were toxic to algae with EC50 values between 1 and 10 mg l⁻¹; Gd0,97CoO3, LaCoO3, LaFeO3 and (La0,5Sr0,5)0,99MnO3 proved to be harmful, having EC50s 10 100 mg l⁻¹; Ce0,9Gd0,1O2 was assessed to be not harmful to algae, because it had an EC50 value >100 mg l⁻¹.The toxicity of non-lanthanide metals (72 h EC50, mg metal l⁻¹) was: Sr (56), Mn (7.4), Fe (7.3), Co, In, Ga and Ni (<1). All studied lanthanides (Ce, Gd, La, Nd, Pr) had 72 h EC50 around 1 mg l⁻¹, i.e. proved to be highly inhibitory to algal growth. The toxicity of lanthanides was not dependent on their atomic number, nor uniform between REE salts, as Pr had a slightly lower EC50 value (0.6 mg l⁻¹).
Inhibition by REEs occurred most probably due to the precipitation of phosphates and carbonates – essential algal medium components – from the medium after binding with REE salts. A significant decrease in dissolved REE concentrations occurred in OECD 201 media after 72 hours of incubation without algae. Because the dissolved REE concentrations in MQ remained the same, it suggests that medium components formed insoluble complexes with REE salts. Thus, both medium components and the REEs were removed from the solution, resulting in an indirect inhibitory effect of REE salts on algae.
All the studied REE salts and composites formed sediments in the test medium, often trapping cells within the agglomerates. Therefore, the toxicity of REE composites was likely related not only to their elemental composition and leaching of constituent metals, but also to particle effects. Consequently, REEs may pose a considerable risk to algae, a very sensitive link in the aquatic ecosystem.
Ключевые слова
lanthanides, rare earth elements, composites, ecotoxicity, aquatic, algae
Введение
Не заполнено
Методы и материалы
Не заполнено
Полученные результаты
Не заполнено
Заключение
Не заполнено
Цитируемая литература
Не заполнено
Благодарности
We are very grateful to Heiki Vija for conducting the TXRF measurements. This research is supported by Estonian Ministry of Education and Research (target-financed theme IUT23-5 and PUT748). The REE composites were provided by Guttorm Syvertsen-Wiig from CerPoTech, Norway.
Название, авторы, резюме (на английском языке)

Doped rare earth oxides and their constituent metals inhibit Raphidocelis subcapitata growth via ion leaching, nutrient removal and agglomeration

Elise Joonas1,2, Villem Aruoja1, Kalle Olli2, Anne Kahru1

1 Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia

2 Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia

Rare earth elements (REEs) are increasingly used in diverse applications, including electronics, renewable energy, and medicine, posing an environmental hazard via various waste streams. We studied the potential toxic impact of nine doped REE oxides (d-REOs) and the corresponding soluble metal salts on the algae Raphidocelis subcapitata (OECD 201 test).

Tentative EC50 (72 h, mg oxide l⁻¹) values for the d-REOs varied from toxic to not harmful: Ce0,8Pr0,2O2, CeO2, (La0,6Sr0,4)0,95CoO3 and La2NiO4 were toxic to algae with EC50 values between 1 and 10 mg l⁻¹; Gd0,97CoO3, LaCoO3, LaFeO3 and (La0,5Sr0,5)0,99MnO3 proved to be harmful, having EC50s 10‑100 mg l⁻¹; Ce0,9Gd0,1O2 was assessed to be not harmful to algae, because it had an EC50 value >100 mg l⁻¹.The toxicity of non-lanthanide metals (72 h EC50, mg metal l⁻¹) was: Sr (56), Mn (7.4), Fe (7.3), Co, In, Ga and Ni (<1). All studied lanthanides (Ce, Gd, La, Nd, Pr) had 72 h EC50 around 1 mg l⁻¹, i.e. proved to be highly inhibitory to algal growth. The toxicity of lanthanides was not dependent on their atomic number, nor uniform between REE salts, as Pr had a slightly lower EC50 value (0.6 mg l⁻¹).

Inhibition by REEs occurred most probably due to the precipitation of phosphates and carbonates – essential algal medium components – from the medium after binding with REE salts. A significant decrease in dissolved REE concentrations occurred in OECD 201 media after 72 hours of incubation without algae. Because the dissolved REE concentrations in MQ remained the same, it suggests that medium components formed insoluble complexes with REE salts. Thus, both medium components and the REEs were removed from the solution, resulting in an indirect inhibitory effect of REE salts on algae.

All the studied REE salts and composites formed sediments in the test medium, often trapping cells within the agglomerates. Therefore, the toxicity of REE composites was likely related not only to their elemental composition and leaching of constituent metals, but also to particle effects. Consequently, REEs may pose a considerable risk to algae, a very sensitive link in the aquatic ecosystem.