Measurements and future projections of Gd-based contrast agents for MRI exams in wastewater treatment plants in the Tokyo metropolitan area

Inoue, Kazuaki; Fukushi, Masahiro; Sahoo, Sarata Kumar; Veerasamy, Nimelan; Furukawa, Akira; Soyama, Sho; Sakata, Ami; Isoda, Ryo; Taguchi, Yoshiaki; Hosokawa, Shota; Sagara, Hiroaki; Natarajan, Thennaarassan

doi:10.1016/j.marpolbul.2021.113259

Cited by 10 publications

(8 citation statements)

References 42 publications

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“…Injections of gadolinium contrast agents and MRI measurements on patients are mainly performed during standard weekday work hours at a hospital . A single-digit increase in the Gd level of treated water was noted at 10 pm on Monday (Figure ).…”

Section: Discussionmentioning

confidence: 99%

“…16 In 2019, filtered treated-water samples from Tokyo's wastewater treatment plants (WWTPs) showed significant positive La and Gd anomalies. 17 In both cases, the source of La enrichment has not yet been identified. Incidentally, La anomalies were not observed in sewage sludge and river water samples collected in Tokyo in 1996.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Since 2011, severe La contamination has been reported in river water and shell samples in the Lower Rhine River due to a spill from a petroleum-refining-catalyst (La-containing zeolite) production plant. − Further, La enrichment was reported in sewage sludge collected in Switzerland in 2016 . In 2019, filtered treated-water samples from Tokyo’s wastewater treatment plants (WWTPs) showed significant positive La and Gd anomalies . In both cases, the source of La enrichment has not yet been identified.…”

Section: Introductionmentioning

confidence: 99%

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

Aktar,

Toyoda

2024

Environ. Sci. Technol. Lett.

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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 12 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., Fosrenol), 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.

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Section: Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Aktar,

Toyoda

2024

Environ. Sci. Technol. Lett.

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“…[24] In addition, the long-term ecotoxicological effects of GBCAs in aquatic environments are also starting to be an issue of concern: the impact of anthropogenic gadolinium is poorly understood and awareness of the need to monitor its distribution and fate in aquatic systems is rapidly growing. [25] Mn(II)-based systems have been proposed as a potential alternative to Gd(III)-based contrast agents for MRI, due to their potentially lower toxicity and favorable relaxation properties. [26] In this work, we propose a new type of chitosan-based nanogel featuring functionalized bisamide-derivatives of t-CDTA (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid; Scheme 1), a chelate that is known to stably coordinate Mn(II) ions.…”

Section: Introductionmentioning

confidence: 99%

“…[ 24 ] In addition, the long‐term ecotoxicological effects of GBCAs in aquatic environments are also starting to be an issue of concern: the impact of anthropogenic gadolinium is poorly understood and awareness of the need to monitor its distribution and fate in aquatic systems is rapidly growing. [ 25 ] Mn(II)‐based systems have been proposed as a potential alternative to Gd(III)‐based contrast agents for MRI, due to their potentially lower toxicity and favorable relaxation properties. [ 26 ]…”

Section: Introductionmentioning

confidence: 99%

Novel Nanogels Loaded with Mn(II) Chelates as Effective and Biologically Stable MRI Probes

Carniato

Ricci

Tei

et al. 2023

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Here it is described nanogels (NG) based on a chitosan matrix, which are covalently stabilized by a bisamide derivative of Mn‐t‐CDTA (t–CDTA = trans‐1,2‐diaminocyclohexane‐N,N,N′,N′‐tetraacetic acid). the Mn(II) complex acts both as a contrast medium and as a cross‐linking agent. These nanogels are proposed as an alternative to the less stable paramagnetic nanogels obtained by electrostatic interactions between the polymeric matrix and paramagnetic Gd(III) chelates. The present novel nanogels show: i) relaxivity values seven times higher than that of typical monohydrated Mn(II) chelates at the clinical fields, thanks to the combination of a restricted mobility of the complex with a fast exchange of the metal‐bound water molecule; ii) high stability of the formulation over time at pH 5 and under physiological conditions, thus excluding metal leaking or particles aggregation; iii) good extravasation and accumulation, with a maximum contrast achieved at 24 h post‐injection in mice bearing subcutaneous breast cancer tumor; iv) high T1 contrast (1 T) in the tumor 24 h post‐injection. These improved properties pave the way for the use of these paramagnetic nanogels as promising magnetic resonance imaging (MRI) probes for in vitro and in vivo preclinical applications.

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