Rare earth element abundances in high phosphorus and low iron groundwaters from the Nishinomiya district, Japan: Variations in Ce anomaly, redox state and heavy rare earth enrichment.

Abstract

High phosphorus and low iron-content groundwaters from the southern Nishinomya district (Miyamizu groundwater), Japan, were analyzed for rare earth element (REE) and some major element concentrations. The chondrite-normalized REE patterns of these groundwaters are characterized by strong heavy REE enrichments relative to light REE, and slight-to-moderate negative Ce anomalies. The magnitude of Ce anomaly increases with decreasing Fe and increasing NO 3 -contents and pH. Such correlations are explained by the redox changes with depth in the area. The heavy REE inclinations of the chondrite-normalized REE patterns correlate positively with Ca and Mg contents and negatively with Fe contents. Heavy REE enrichment is explained by successive water-rock interactions supplying REE to the water in which differential scavenging of light REE by particulate matters occurs. The high P characteristic is achieved by the decomposition of biogenic materials under oxidizing conditions. The low Fe concentration of these groundwaters is ascribed to precipitation of Fe-hydroxides and their subsequent filtration as groundwater flows through the aquifer. The low P and high Fe groundwaters are thought to originate from a deeper aquifer experiencing reducing conditions. The unique geochemical characteristics of the groundwaters of the study area may be closely related to a peculiar geological situation in which an organic-rich layer is seated at relatively shallow depths within an aquifer of relatively large permeability.

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

“…1.03E-5 1.49E-5 3.59E-5 3.31E-6 6.39E-7 1.66E-5 1.17E-5 9.94E-6 1. reported for the ground-waters from the western region of the Muko river delta (Otsuka and Terakado, 2003). The STP effluent samples show overall heavy REE enrichments similar to the seawater and river waters (Fig.…”

“…However, such disagreement is not surprising, because many STP locate in the area and their Gd values might be variable. Such variability is clarified by variable Gd data for the river water samples from Yodo and Syuku rivers (cf., Otsuka and Terakado, 2003).…”

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.…”

Chemical condition for the appearance of a negative Ce anomaly in stream waters and groundwaters

“…The data discussed in this paper are cited from nine publications (Table 1): Three references to riverwater (Dupré et al, 1996;Gaillardet et al, 1997;Nakajima and Terakado, 2003), five references to groundwater (Smedley, 1991;Braun et al, 1998;Dia et al, 2000;Otsuka and Terakado, 2003;Gruau et al, 2004) and one reference to swamp water (Johannesson et al, 2004). The nine publications cover most typical terrestrial waters ranging from a low (Dupré et al, 1996;Gaillardet et al, 1997) to high latitude (Dia et al, 2000;Gruau et al, 2004).…”

“…The samples Otsuka and Terakado (2003) investigated were groundwaters from the southern Nishinomiya district near the sites of Nakajima and Terakado (2003). The alluvial plain on which the urban areas of Nishinomiya and neighboring cities lie is located in the southeast of the Rokko Mountains.…”