Dissolved Mo and U in rivers and estuaries of India: Implication to geochemistry of redox sensitive elements and their marine budgets

Rahaman, Waliur; Singh, Sunil Kumar; Raghav, Sanjeev

doi:10.1016/j.chemgeo.2010.09.009

Cited by 60 publications

(36 citation statements)

References 57 publications

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“…Among the three rivers, the lowest concentration of dissolved Sr is in the Mandovi, consistent with the lateritic lithology exposed in its drainage basin, its higher runoff and lower water-rock interaction. This inference is also corroborated by its lowest alkalinity and concentrations of dissolved U, Mo and Re among the three rivers analysed (Rahaman et al, 2011).…”

Section: Dissolved Sr and 87 Sr/ 86 Srsupporting

confidence: 60%

“…Briefly, in the Narmada estuary, the pH remains within a narrow range of $8, unlike the Tapi and the Mandovi estuaries which show variation between 7.57-8.02 and 6.61-8.18, respectively (Rahaman and Singh, 2010). Alkalinity lies between 2000 and 3000 leq/' in the Narmada and the Tapi estuaries where as in the Mandovi it ranges from 384 to 2236 leq/' (Rahaman et al, 2011). Lower pH and alkalinity in the Mandovi river is due to limited water-rock interaction in its basin, particularly carbonate dissolution.…”

Section: Resultsmentioning

confidence: 97%

“…1) are sampled in this study for their Sr concentration and 87 Sr/ 86 Sr ratio. This study is a part of our investigations on the behaviour of selected trace elements in Indian estuaries (Rahaman and Singh, 2010;Rahaman et al, 2011). The Narmada originates from Amarkantak in the Vindhyan Mountains in Madhya Pradesh (MP) and flows through Deccan basalts, Vindhyan sediments and alluvium before entering the Gulf of Cambay off Bharuch (Fig.…”

Section: Study Areamentioning

confidence: 99%

“…In addition, the Sr data for the two groundwater samples (depths $18 and $24 m) analysed are also given in Table 1. The chemical characteristics of these estuaries are discussed in Rahaman and Singh (2010) and Rahaman et al (2011).…”

Section: Dissolved Sr and 87 Sr/ 86 Srmentioning

confidence: 99%

See 3 more Smart Citations

Sr and 87Sr/86Sr in estuaries of western India: Impact of submarine groundwater discharge

Rahaman

Singh

2012

Geochimica et Cosmochimica Acta

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Section: Dissolved Sr and 87 Sr/ 86 Srsupporting

confidence: 60%

Section: Resultsmentioning

confidence: 97%

Section: Study Areamentioning

confidence: 99%

Section: Dissolved Sr and 87 Sr/ 86 Srmentioning

confidence: 99%

See 2 more Smart Citations

Sr and 87Sr/86Sr in estuaries of western India: Impact of submarine groundwater discharge

Rahaman

Singh

2012

Geochimica et Cosmochimica Acta

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“…Another possibility is that small and real deviations from conservative behavior actually exist for Mo. Non-conservative signatures have actually been observed for dissolved Mo concentrations in estuarine and coastal waters (Dellwig et al, 2007;Rahaman et al, 2010) and in the eastern tropical Pacific (Tuit and Ravizza, 2003). The non-conservative signatures also reported for δ 98/ 95 Mo in the low salinity zone of an estuary (Pearce et al, 2010a).…”

Section: Homogeneity Of Mo Isotopes In the Modern Oxic Oceanmentioning

confidence: 90%

The molybdenum isotopic composition of the modern ocean

et al. 2012

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Wang et al., 2011 (1) and is converted to δ 97/95 Mo by multiplying 0.67 when the system follows mass-dependent fractionation. Though no commonly-used Mo isotopic standard currently exists (see later), the standards used by different laboratories do appear to be isotopically similar at the level of 0.1-0.2‰. Continental rock samples, such as granite, basalt, and clastic sediments, have δ 98/95 Mo of ~0.1‰ Siebert et al., 2003). Ferromanganese oxides, which scavenge Mo from seawater in oxic conditions, have a light isotopic signature (δ 98/95 Mo = -1.0 to -0.5‰; Siebert et al., 2003), whereas sediments formed in euxinic conditions (aqueous H 2 S concentrations higher than ~11 µM, the action point pro-The molybdenum isotopic composition of the modern ocean (Received September 13, 2011; Accepted January 5, 2012) Natural variations in the isotopic composition of molybdenum (Mo) are showing increasing potential as a tool in geochemistry. Although the ocean is an important reservoir of Mo, data on the isotopic composition of Mo in seawater are scarce. We have recently developed a new method for the precise determination of Mo isotope ratios on the basis of preconcentration using a chelating resin and measurement by multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), which allows us to measure every stable Mo isotope . In this study, 172 seawater samples obtained from 9 stations in the Pacific, Atlantic, and Southern Oceans were analyzed, giving global coverage and the first full depth-profiles. The average isotope composition in δ Three-isotope plots for the Mo isotopes were fitted with straight lines whose slopes agreed with theoretical values for mass-dependent isotope fractionation. These results demonstrate that Mo isotopes are both uniformly distributed and follow a mass-dependent fractionation law in the modern oxic ocean. In addition, Mo isotopic analysis revealed that δ 98/95 Mo of the standard used in this study was 0.117 ± 0.009‰ lighter than the Mo standard that was used by Archer and Vance (2008). A common Mo standard is urgently required for the precise comparison of Mo isotopic compositions measured in different laboratories. On the other hand, our results strongly support the possibility of seawater as an international reference material for Mo isotopic composition.

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The nonconservative property of dissolved molybdenum in the western Taiwan Strait: Relevance of submarine groundwater discharges and biological utilization

Wang

Xia

et al. 2016

Geochem Geophys Geosyst

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This study examined dissolved Mo and sedimentary Mo along with hydrochemical parameters in the western Taiwan Strait (WTS) in May and August 2012. The results demonstrate that dissolved Mo could be depleted of as high as 10–20 nM during our May sampling period when the nutrient‐enriched Min‐Zhe coastal current ceased and spring blooms developed. The negative correlation between Chl‐a and dissolved Mo suggests the possible involvement of high algal productivity in removing dissolved Mo out of the water column. Specific oceanographic settings (little currents) permitted a high sedimentary enrichment of Mo (>6 µg/g Mo) within the highly productive waters outside the Jiulong River mouth. Possibly, the high algal productivities and consequent organic matter sinks provide a pathway of Mo burial from water columns into sediments. Dissolved Mo was relatively high in groundwater samples, but we observed that submarine groundwater discharges (SGDs) only contributed to a relatively small percentage of the total dissolved Mo pool in WTS. It is probably attributable to the immediate removal of SGD‐released Mo ions via adsorption onto newly formed Mn oxides once exposed to oxygenated seawater, followed by an elevated sedimentary Mo accumulation near the SGDs (∼5 µg/g). In addition to metal oxide particle scavenging and sulfide precipitation, we estimated that biological uptake along with Mo adsorption onto organic matter carriers could finally provide more than 10% of the annual sedimentary Mo accumulation in WTS.

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Dissolved Mo and U in rivers and estuaries of India: Implication to geochemistry of redox sensitive elements and their marine budgets

Cited by 60 publications

References 57 publications

Sr and 87Sr/86Sr in estuaries of western India: Impact of submarine groundwater discharge

Sr and 87Sr/86Sr in estuaries of western India: Impact of submarine groundwater discharge

The molybdenum isotopic composition of the modern ocean

The nonconservative property of dissolved molybdenum in the western Taiwan Strait: Relevance of submarine groundwater discharges and biological utilization

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