open access

https://hdl.handle.net/2115/99468

Hospital Effluent as a New Source of Anthropogenic Lanthanum in the Environment

英語

Lanthanum carbonate

2024-05-30

American Chemical Society(ACS)

Environmental Science and Technology Letters

11(6)

598-603

Excess gadolinium (Gd) in the environment, originating from Gd-chelating contrast agents present in hospital wastewater, has been extensively studied as a micropollutant. However, the source of excessive lanthanum (La) levels in the environment remains unclear. In this study, we analyzed rare earth elements (REEs) in treated water from nine wastewater treatment plants (WWTPs) and sewage sludge/incinerated ash from two sludge treatment centers in Sapporo, Japan, during 2019-2020. We found that the annual discharge of excess Gd and La in a treatment area positively correlated with the number of hospitals in that area. The excess Gd concentration in the treated water increased by an order of magnitude late at night Monday, whereas the excess La concentration remained constant. Sequential extraction experiments on sewage sludge revealed that excess La is predominantly incorporated in phosphate, not silicate, as in zeolite catalysts. We identified lanthanum carbonate tablets (e.g., FosrenolR), prescribed daily to kidney patients to prevent hyperphosphatemia, as the source of excess La. Due to its low solubility, most of the anthropogenic lanthanum settles as sewage sludge in WWTPs, and only a small percentage is released into treated water. This raises concerns about the potential degradation of natural REE patterns in the environment.

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science and Technology Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/articlesonrequest/AOR-QSWJSXDBW8DFAA88TQAS.

2328-8930