Spatial variability of caesium-137 inventories at reference sites: an example from two contrasting sites in England and Zimbabwe

doi:10.1016/0969-8043(96)00015-2

Applied Radiation and Isotopes

Volume 47, Issue 7, July 1996, Pages 699-707

https://doi.org/10.1016/0969-8043(96)00015-2 Get rights and content

Abstract

Bomb-derived caesium-137 (¹³⁷Cs) fallout has been widely used to investigate rates and patterns of soil erosion and sediment deposition. Within this approach considerable importance is placed on establishing the local total ¹³⁷Cs fallout or inventory at a reference site. However, relatively little information currently exists concerning the variability of ¹³⁷Cs inventories at reference sites. This paper reports an investigation of the spatial variability of ¹³⁷Cs inventories at two contrasting reference sites at Yendacott, England and Msana, Zimbabwe. Replicate bulk soil cores were collected at the intersections of a grid, yielding 60 and 27 samples from Yendacott and Msana, respectively. Although the total variability may be derived from four sources (random spatial, systematic spatial, sampling and measurement), the observed variability was in both cases primarily due to random spatial variations in ¹³⁷Cs inventories. The reference inventory range (at the 95% confidence level) was 205–230 and 17.0–33.4 mBq cm⁻² for the Yendacott and Msana sites, respectively.

References (40)

K. Bunzl et al.
Cumulative deposition of ¹³⁷Cs, ²³⁸Pu, ^{239 + 240}Pu and ²⁴¹Am from global fallout in soils from forest, grassland and arable land in Bavaria (FRG)
J. Environ. Radioact.
(1988)
Q. He et al.
Interpreting particle size effects in the adsorption of ¹³⁷Cs and unsupported ²¹⁰Pb by mineral soils and sediments
J. Environ. Radioact.
(1996)
F.R. Livens et al.
Particle size and radionuclide levels in some west Cumbrian soils
Sci. Total Environ.
(1988)
R.J. Loughran et al.
Estimation of soil erosion from caesium-137 measurements in a small, cultivated catchment in Australia
Appl. Radiat. Isot.
(1988)
R.G. Menzel et al.
Estimating soil erosion losses in Korea with fallout caesium-137
Appl. Radiat. Isot.
(1987)
R.A. Sutherland
Examination of caesium-137 areal activities in control (uneroded) locations
Soil Technol.
(1991)
P.H. Beckett et al.
Soil variability: a review
Soil Fertilis.
(1971)
R.B. Brown et al.
Agricultural erosion indicated by ¹³⁷Cs redistribution: II. Estimates of erosion rates
Soil Sci. Soc. Am. J.
(1981)
B.L. Campbell et al.
A method for determining sediment budgets using caesium-137
E. De Jong et al.
Preliminary investigations on the use of ¹³⁷Cs to estimate erosion in Saskatchewan
Can. J. Soil Sci.
(1982)

E. De Jong et al.

Soil redistribution on three New Brunswick hillslopes calculated from ¹³⁷Cs measurements, solum data and the USLE

Can. J. Soil Sci.

(1986)

R.L. Folk et al.

Brazos River bar: a study in the significance of grain-size parameters

J. Sediment. Petrol.

(1957)

I.D.L. Foster et al.

Quantifying soil erosion and sediment transport in drainage basins; some observations on the use of ¹³⁷Cs

R.E. Franklin et al.

Analysis of gamma-ray spectra from soils and plants: II. Effects of trees on the distribution of fallout

D.J. Fredericks et al.

Estimating erosion using caesium-137: I. Measuring caesium-137 activity in a soil

Q. He et al.

Interpreting the ¹³⁷Cs profiles observed in several small lakes and reservoirs in southern England

Chemical Geology

(1996)

J.C. Lance et al.

Measuring sediment movement at low erosion rates using cesium-137

Soil Sci. Soc. Am. J.

(1986)

R.J. Loughran et al.

The identification and quantification of sediment sources using caesium-137

R.J. Loughran et al.

Soil erosion and sedimentation indicated by caesium-137: Jackmoor Brook catchment, Devon, England

Catena

(1987)

M.E. McCallan et al.

Redistribution of caesium-137 by erosion and deposition on an Australian soil

Austral. J. Soil Res.

(1980)

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Spatial variability of caesium-137 inventories at reference sites: an example from two contrasting sites in England and Zimbabwe

Abstract

J. Environ. Radioact.

J. Environ. Radioact.

Sci. Total Environ.

Appl. Radiat. Isot.

Appl. Radiat. Isot.

Soil Technol.

Soil variability: a review

Soil Fertilis.

Agricultural erosion indicated by 137Cs redistribution: II. Estimates of erosion rates

Soil Sci. Soc. Am. J.

A method for determining sediment budgets using caesium-137

Preliminary investigations on the use of 137Cs to estimate erosion in Saskatchewan

Can. J. Soil Sci.

Soil redistribution on three New Brunswick hillslopes calculated from 137Cs measurements, solum data and the USLE

Can. J. Soil Sci.

Brazos River bar: a study in the significance of grain-size parameters

J. Sediment. Petrol.

Quantifying soil erosion and sediment transport in drainage basins; some observations on the use of 137Cs

Analysis of gamma-ray spectra from soils and plants: II. Effects of trees on the distribution of fallout

Estimating erosion using caesium-137: I. Measuring caesium-137 activity in a soil

Interpreting the 137Cs profiles observed in several small lakes and reservoirs in southern England

Chemical Geology

Measuring sediment movement at low erosion rates using cesium-137

Soil Sci. Soc. Am. J.

The identification and quantification of sediment sources using caesium-137

Soil erosion and sedimentation indicated by caesium-137: Jackmoor Brook catchment, Devon, England

Catena

Redistribution of caesium-137 by erosion and deposition on an Australian soil

Austral. J. Soil Res.

Agricultural erosion indicated by ¹³⁷Cs redistribution: II. Estimates of erosion rates

Preliminary investigations on the use of ¹³⁷Cs to estimate erosion in Saskatchewan

Soil redistribution on three New Brunswick hillslopes calculated from ¹³⁷Cs measurements, solum data and the USLE

Quantifying soil erosion and sediment transport in drainage basins; some observations on the use of ¹³⁷Cs

Interpreting the ¹³⁷Cs profiles observed in several small lakes and reservoirs in southern England