A new ground-level fallout record of uranium and plutonium isotopes for northern temperate latitudes

Warneke, Thorsten; Croudace, Ian W.; Warwick, Phillip E.; Taylor, Rex N.

doi:10.1016/s0012-821x(02)00930-5

Cited by 188 publications

(125 citation statements)

References 16 publications

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“…Figure 3 shows the 240 Pu/ 239 Pu ratios for sites T006-T008 are well below the global fallout average of ~0.18 [16,17], and also below the Australian average of ~0.14 [13]. The high concentrations and low ratios, which at sites T007 and T008 yield 240 Pu/ 239 Pu ratios consistent with undetonated weapons material [18], indicate that the Pu at these two sites is overwhelmingly derived from the safety trials which dispersed the weapons material using conventional explosives. The data for site T006 also suggests the presence of trials material, with ratios and concentrations between the two end members.…”

Section: Resultsmentioning

confidence: 90%

Measurements of low-level anthropogenic radionuclides from soils around Maralinga

Tims

Tsifakis

Srncik

et al. 2013

EPJ Web of Conferences

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Abstract. The isotopes 239 Pu and 240 Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes constitute artificial tracers of recent soil erosion and sediment movement. In practice the high throughput capabilities and high sensitivity of the AMS technique makes the study of Australia's geographically large areas viable using Pu isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The contribution from the Maralinga tests to the Pu isotopic abundances present in the region around Maralinga is largely unknown. In global fallout, for example, the 240 Pu/ 239 Pu ratio is typically in the range 0.17 -0.19, but the influence of the regional tests could lead to values outside this range. This would impact on the assessment techniques used in the soil and sediment tracer studies. We report recent measurements on soil samples collected from across the Maralinga Test site.

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Section: Resultsmentioning

confidence: 90%

Measurements of low-level anthropogenic radionuclides from soils around Maralinga

Tims

Tsifakis

Srncik

et al. 2013

EPJ Web of Conferences

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“…Peak 137 Cs activity in core material identifies sediment deposited around 1963AD 261 when above ground testing of nuclear weapons was at its maximum (Warneke et al, 2002). per unit of production or consumption changed through time, trends rather than absolute values were the 283 basis for recognizing these features in core CMC8.…”

Section: Isotopes 258 259mentioning

confidence: 99%

Sea-level change during the last 2500 years in New Jersey, USA

Kemp

Horton

Vane

et al. 2013

Quaternary Science Reviews

133

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18Relative sea-level changes during the last ~2500 years in New Jersey, USA were reconstructed to test if 19 late Holocene sea level was stable or included persistent and distinctive phases of variability. 20Foraminifera and bulk-sediment δ 13 C values were combined to reconstruct paleomarsh elevation with 21 decimeter precision from sequences of salt-marsh sediment at two sites using a multi-proxy approach. 22The history of sediment deposition was constrained by a composite chronology. An age-depth model 23 developed for each core enabled reconstruction of sea level with multi-decadal resolution. Following 24 correction for land-level change (1.4mm/yr), four successive and sustained (multi-centennial) sea-level 25 trends were objectively identified and quantified using error-in-variables change point analysis to account 26 for age and sea-level uncertainties. From at least 500BC to 250AD sea-level fell at 0.11mm/yr. The 27 second period saw sea-level rise at 0.62mm/yr from 250AD to 733AD. Between 733AD and 1850AD sea 28 level fell at 0.12mm/yr. The reconstructed rate of sea-level rise since ~1850AD was 3.1mm/yr and 29 represents the most rapid period of change for at least 2500 years. This trend began between 1830AD and 30 1873AD and its onset is synchronous with other locations on the U.S. Atlantic coast. Since this change 31 point, reconstructed sea-level rise is in agreement with regional tide-gauge records and exceeds the global 32 average estimate for the 20 th century. These positive and negative departures from background rates 33 demonstrate that the late Holocene sea level was not stable in New Jersey. 34 35

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“…However, when averaged over all the weapons tests, the global integrated fallout 240 Pu/ 239 Pu atom ratio in environmental samples is about 0.18 (Kelley et al, 1999;Krey et al, 1976). These isotopic signatures have been successfully used to trace the specific Pu source such as global weapons testing fallout, debris from specific test series or Pu from reprocessing or a local reactor discharge in differing hydro-geochemical regime (Beasley et al, 1981;Buesseler, 1997;Buesseler and Sholkovitz, 1987;Cooper et al, 2000;Dresel et al, 2002;Perkins and Thomas, 1980;Taylor et al, 2001;Warneke et al, 2002) In this study, we have measured 240 Pu/ 239 Pu ratios ranging from <0.04 to >0.15 in the K-Basin groundwater and 0.18 in the Columbia River downstream of the 100K-Area (Figure 5a). This isotopic composition range is consistent overall with prior measurements in Hanford Site soils, which were 0.0522±0.0005 within a mile from the PUREX fuel reprocessing plant, 0.0957±0.0013 within 2 miles from the plant and 0.1785±0.0095 at a site 200 miles from the plant (Stoffels et al, 1994).…”

Section: Isotopic Ratios and Source Provenancementioning

confidence: 99%

Plutonium in groundwater at the 100K-Area of the U.S. DOE Hanford Site

Dai

Buesseler

Pike

2005

Journal of Contaminant Hydrology

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We examined the concentration, size distribution, redox state and isotopic composition of plutonium (Pu) in groundwater at the 100K-Area at the US Department of Energy's (DOE) Hanford Site. Total concentrations of Pu isotopes were extremely low (10 -4 to 10 -6 pCi/kg, ≈ 10 4 to 10 6 atoms/kg), but measurable for the first time in the 100K-Area wells using mass spectrometric analyses that are much more sensitive than alpha spectroscopy methods used previously. Size fractionation data from two wells suggests that 7-29% of the Pu is associated with colloids, operationally defined here as particles between 1 kDa -0.2 µm in size. These colloids were collected using a 1 kDa cross-flow ultrafiltration system developed specifically for groundwater actinide studies to include careful controls both in the field and during processing to ensure in-situ geochemical conditions are maintained and size separations can be well characterized. Pu in this colloidal fraction was exclusively in the more reduced Pu(III/IV) form, consistent with the higher affinity of Pu for particle surfaces in the lower oxidation states. While the overall concentrations of Pu were low, the Pu isotopic composition suggests at least two local sources of groundwater Pu, namely local Hanford reactor operations at the 100K-Area, and spent nuclear fuel from the N reactor, which was stored in concrete pools at this site.Differences between this site and the Savannah River Site (SRS) are noted, since groundwater Pu at the F-Area seepage basin at SRS has been found using these same 2 methods, to be characterized by much lower colloidal abundances and higher oxidation states. This difference is not directly attributable to groundwater redox potential or geochemical conditions, but rather the physical-chemical difference in Pu sources, which at SRS appear to be dominated downstream from the seepage basins by decay of 244 Cm, resulting in more oxidized forms of 240 Pu. There is no clear evidence for colloid facilitated transport of Pu in groundwater at this site, since downstream wells have both an order of magnitude lower concentrations of Pu, but also a lower fractional colloidal distribution.

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A new ground-level fallout record of uranium and plutonium isotopes for northern temperate latitudes

Cited by 188 publications

References 16 publications

Measurements of low-level anthropogenic radionuclides from soils around Maralinga

Measurements of low-level anthropogenic radionuclides from soils around Maralinga

Sea-level change during the last 2500 years in New Jersey, USA

Plutonium in groundwater at the 100K-Area of the U.S. DOE Hanford Site

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