Evaluation of Recharge Mechanism of Confined Groundwater Using Long Term Tritium Concentration Records in the Metropolis of Tokyo.

Imaizumi, Mitsuru; Komae, Takami; Nihira, Satoshi

doi:10.5110/jjseg.41.87

Cited by 6 publications

(8 citation statements)

References 8 publications

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“…In confined aquifers, groundwater flows from southwest to northeast (Figure S2 in SI). The residence time of the confined groundwaters in Tokyo at depths of 40–124 m BGL was estimated, using tritium, to be 11–28 years . This relatively short residence time compared with the depth can be explained by the geology, as seen in Figure and Figure S1 (SI).…”

Section: Methodsmentioning

confidence: 99%

Assessment of Groundwater Pollution in Tokyo Using PPCPs as Sewage Markers

Kuroda

Murakami

Oguma

et al. 2012

Environ. Sci. Technol.

131

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While the occurrence of pharmaceuticals and personal care products (PPCPs) in groundwater has typically been reported in bank filtration sites, irrigated fields, septic tanks, and sewage disposal practices, fewer studies have been conducted in highly urbanized areas, where infiltration of treated or untreated sewage is not supposed to be a source of groundwater recharge. Furthermore, little is known about the occurrence of various kinds of PPCPs in relation to microbial indicators in groundwater from different types of aquifers. Thus, we examined the city-wide occurrence of selected PPCPs (diethyltoluamide, crotamiton, ethenzamide, propyphenazone, carbamazepine, and caffeine) and E. coli in 50 groundwaters from unconfined aquifers (<30 m in depth) and confined aquifers (up to 500 m in depth) in Tokyo, where unintended groundwater contamination could take place due to decrepit sewer networks. PPCPs were detected in unconfined aquifers and springs (23/34 samples, 68%), and in confined aquifers (7/16 samples, 44%). Compared with published results for sewage influents, concentrations of PPCPs, excluding caffeine, were generally 1-2 orders of magnitude lower, while in some samples concentrations were quite comparable. The high occurrence rate of PPCPs, even in confined aquifers, indicated that such aquifers are not always protected from pollution by sewage near the land surface. Among the PPCPs analyzed, carbamazepine and crotamiton were most frequently detected, which would appear to be owing to their high persistence, combined with the high concentration of crotamiton in sewage. Crotamiton was detected in all four E. coli-positive groundwaters, and thus may potentially serve as a precautionary indicator of E. coli contamination. Using carbamazepine as a sewage marker, we estimated that 0.8%-1.7% of the dry-weather flow of sewage was leaking out into the unconfined aquifers.

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Section: Methodsmentioning

confidence: 99%

Assessment of Groundwater Pollution in Tokyo Using PPCPs as Sewage Markers

Kuroda

Murakami

Oguma

et al. 2012

Environ. Sci. Technol.

131

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“…1). The study site is located about 3.5 km from Tama River and 35 km from Kanto Mountains in Kanagawa prefecture (Endo and Ishii 1984;Endo 1992;Imaizumi et al 2000). The groundwater is therefore expected to be influenced by relatively high-DO content water from those water sources.…”

Section: Environmental Factorsmentioning

confidence: 99%

“…The elevation of Fuchu is about 30-80 m above the mean sea level. Groundwater in shallow confined aquifers is originated from the Kanto Mountains in Kanagawa prefecture and Tama River (Endo and Ishii 1984;Endo 1992;Imaizumi et al 2000). Stratigraphy of the study area consists of two groups: the upper Tokyo group and the lower Kazusa group (Endo 1992).…”

Section: Experimental Site Descriptionmentioning

confidence: 99%

Multivariate analysis of trace elements in shallow groundwater in Fuchu in western Tokyo Metropolis, Japan

Thuyet

Saito

et al. 2016

Environ Earth Sci

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A rapid increase in the use of ground source heat pump (GSHP) systems for heating and cooling of buildings potentially threatens to harm shallow groundwater quality. As a necessary preliminary step toward evaluating GSHP impact on shallow groundwater quality, this study used multivariate statistical analyses to investigate characteristics of trace elements in groundwater in Fuchu city in western Tokyo Metropolis. Water samples were collected twice a month from two aquifers at 30-and 45-m depths using four observation wells for more than a year. Concentrations of 14 trace elements (Li, B, Al, Cr, Mn, Fe, Ni, Cu, As, Se, Sr, Cd, Sb, and Pb) and Si as well as oxidation-reduction potential (ORP), dissolved oxygen (DO), electrical conductivity (EC), and pH were measured. All elements were under the environmental water quality criteria issued by the Japanese Ministry of the Environment. No clear seasonal trends were observed in the concentrations of 15 elements in groundwater. Principal component analyses showed the element properties were well characterized by three principal components (PC). PC1, which represents the more mobile trace elements in the groundwater, consisted of Li, B, Mn, Fe, As, and Si. PC2 included Al, Ni, Cd, and Sb, and represents ORPinsensitive properties. PC3 consisted of Pb, Cu, and Se, which are less mobile in groundwater. Samples collected from the same aquifer had high similarity in distribution and variation of the trace elements. This study proposes a useful statistical platform for assessing future effects of GSHP systems on shallow groundwater quality.

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“…However, the elevated PPCP levels were not observed in the canals' vicinity and PPCPs were detected widely in the region (Kuroda et al, 2012). The residence time of the confined groundwater in Tokyo, at depths of 40-124 m BGL, was estimated to be 11-28 years, using tritium analysis (Imaizumi et al, 2000). This relatively short residence time, relative to the depth, can be explained by the geology (see Figure S1) Research, 1996) and Figure S1).…”

Section: Groundwater Rechargementioning

confidence: 98%

“…First, subsurface attenuation of PFAAs may be slower than that of PPCPs. The residence time of confined aquifers of 40-124 m depth were estimated to be 11-28 years (Imaizumi et al, 2000) and that of unconfined aquifers and springs would be shorter. The half-life of carbamazepine in groundwater is typically 5-10…”

Section: Comparison Of Pfaa and Ppcp Levelsmentioning

confidence: 98%

Investigating sources and pathways of perfluoroalkyl acids (PFAAs) in aquifers in Tokyo using multiple tracers

Kuroda

Murakami

Oguma

et al. 2014

Science of The Total Environment

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We employed a multi-tracer approach to investigate sources and pathways of perfluoroalkyl acids (PFAAs) in urban groundwater, based on 53 groundwater samples taken from confined aquifers and unconfined aquifers in Tokyo. While the median concentrations of groundwater PFAAs were several ng/L, the maximum concentrations of perfluorooctane sulfonate (PFOS, 990 ng/L), perfluorooctanoate (PFOA, 1800 ng/L) and perfluorononanoate (PFNA, 620 ng/L) in groundwater were several times higher than those of wastewater and street runoff reported in the literature. PFAAs were more frequently detected than sewage tracers (carbamazepine and crotamiton), presumably owing to the higher persistence of PFAAs, the multiple sources of PFAAs beyond sewage (e.g., surface runoff, point sources) and the formation of PFAAs from their precursors. Use of multiple methods of source apportionment including principal component analysis-multiple linear regression (PCA-MLR) and perfluoroalkyl carboxylic acid ratio analysis highlighted sewage and point sources as the primary sources of PFAAs in the most severely polluted groundwater samples, with street runoff being a minor source (44.6% sewage, 45.7% point sources and 9.7% street runoff, by PCA-MLR). Tritium analysis indicated that, while young groundwater (recharged during or after the 1970s, when PFAAs were already in commercial use) in shallow aquifers (<50 m depth) was naturally highly vulnerable to PFAA pollution, PFAAs were also found in old groundwater (recharged before the 1950s, when PFAAs were not in use) in deep aquifers (50-500 m depth). This study demonstrated the utility of multiple uses of tracers (pharmaceuticals and personal care products; PPCPs, tritium) and source apportionment methods in investigating sources and pathways of PFAAs in multiple aquifer systems.

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Evaluation of Recharge Mechanism of Confined Groundwater Using Long Term Tritium Concentration Records in the Metropolis of Tokyo.

Cited by 6 publications

References 8 publications

Assessment of Groundwater Pollution in Tokyo Using PPCPs as Sewage Markers

Assessment of Groundwater Pollution in Tokyo Using PPCPs as Sewage Markers

Multivariate analysis of trace elements in shallow groundwater in Fuchu in western Tokyo Metropolis, Japan

Investigating sources and pathways of perfluoroalkyl acids (PFAAs) in aquifers in Tokyo using multiple tracers

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