Rare earth element abundances in some seawaters and related river waters from the Osaka Bay area, Japan: Significance of anthropogenic Gd

Abstract

Some major and trace elements in seawaters and related river waters from the Osaka Bay area, Japan were analyzed in order to examine rare earth element (REE) behaviors, especially the relationship between anthropogenic gadolinium (Gd) and nutrient concentrations. The local silicic rock normalized REE patterns for the seawaters show features of light REE depletion, negative Ce anomaly, and very small Eu anomaly. Moreover, some samples have obvious positive Gd anomalies due to contamination of Magnetic Resonance Imaging (MRI) contrast agents in medical use. We calculated the anthropogenic Gd concentrations by subtracting the assumed natural Gd concentration from the measured one. The anthropogenic or excess Gd concentrations of the seawater samples are well correlated with nutrient concentrations (NH 4 -N, NO 2 -N, NO 3 -N, PO 4 -P). Because both anthropogenic Gd and nutrients are abundant in sewage treatment plant (STP) effluents and much less abundant in non-contaminated river and seawaters, the observed trends can be explained by dilution of STP effluents with non-contaminated river and seawaters. It was found that the nutrient concentrations for a hypothetical STP effluent calculated by using these correlation lines are consistent with the average nutrient contents for the STP effluents in the study area. Moreover, we made a rough estimation of Gd budget in Osaka Bay. The estimated amount of the Gd MRI contrast agents consumed in the area seems to be consistent with the excess Gd concentrations of river and STP waters. The Gd observations in this study suggest that the Gd anomaly data can be used as a geochemical tracer of wastewater component in urban areas.

Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species

“…Gd pollution is measured as "the Gd anomaly", calculated as the ratio of the measured Gd concentration in a sample with respect to the background levels of Gd due to geological processes. Positive Gd anomalies were observed in several rivers, lakes and in seawater from different locations (Bau and Dulski, 1996;Nozaki et al, 2000;Elbaz-Poulichet et al, 2002;Zhu et al, 2004;Ogata and Terakado, 2006;Kulaksiz and Bau, 2007). The Gd anomaly is determined using only the total Gd concentration, without information about the speciation of the Gd present in the sample (Bau and Dulski, 1996).…”

Influence of dissolved organic matter on rare earth elements and yttrium distributions in coastal waters

“…After colloidal coagulation, LREE are enriched in SPM due to their high particle reactivity, whereas MREE and HREE are enriched in the dissolved phase. In this phase the recognition of positive Gd anomaly values suggests an anthropogenic signature, Gd organic compounds, being widely used as contrast medium in magnetic resonance imaging [9,[59][60][61]. Moreover, LREE enrichment observed in shale-normalised SPM patterns represents a further effect of anthropogenic pressure [62] and agrees with the organic-rich nature of the authigenic SPM fraction [63].…”

Rare earth elements, Sr, Ba, Fe, and major cation concentrations in some living foraminiferal tests collected from Iriomote Island, Japan: An exploration for trace element behavior during biogenic calcium carbonate formation

“…REE, Ba, Sr and Rb were measured by mass-spectrometric isotope dilution using a thermal ionization mass spectrometer. The latter method has been used widely for the accurate determination of trace elements in geochronology and in trace element geochemistry for rocks and water samples (e.g., Terakado and Masuda, 1979;Otsuka and Terakado, 2003;Nakajima and Terakado, 2003;Ogata and Terakado, 2006). Co-precipitation with Fe-hydroxide was used for trace element separation from major cations (e.g., Masuda and Ikeuchi, 1979), and conventional ion exchange column method was applied for further purification and separation of trace elements.…”