Preliminary results of usingCs to study wind erosion in the Qinghai-Tibet Plateau

The world fallout of caesium-137 (¹³⁷Cs) associated with nuclear weapons testing during the 1950s and 1960s has provided a valuable man-made tracer for studies of soil erosion and sediment delivery. But relatively few researchers have used it to estimate wind erosion. In this paper, the¹³⁷Cs technique is introduced into the study of wind erosion and its modern processes in the Qinghai-Tibet Plateau. Two¹³⁷Cs reference inventories of 982·11 and 2376·04 Bq m⁻²was established preliminarily, which distribute in the south and mid-north parts of the study area respectively. By analysing the patterns of¹³⁷Cs depth profiles from sampling sites, the aeolian processes of erosion and deposition along nearly 40 years has been revealed, i.e. the shrub coppice dunes(S1) and semi-fixed dunefields (S3) had experienced the alternation of erosion and deposition, while the grasslands (S4, S6 and S7) and dry farmlands (S5) suffered erosion only. By using the¹³⁷Cs model, the average wind erosion rates for shrub coppice dune (S1), semi-fixed dunefields (S3), dry farmlands (S5) and grasslands (S4, S6 and S7) were estimated to be 84·14, 69·43, 30·68 and 21·84 tha⁻¹a⁻¹respectively, and for the whole Plateau, averaging 47·59 ha⁻¹a⁻¹which can be regarded as the medium erosion standard. These results derived from¹³⁷Cs for the first time have significant implications for the further research of wind erosion and desertification control in the Qinghai-Tibet Plateau.     

Using unsupported lead-210 measurements to investigate soil erosion and sediment delivery in a small Zambian catchment

Traditional techniques used to assemble information on rates of erosion and soil redistribution possess many important limitations. As a result, the use of environmental radionuclides, and more particularly ¹³⁷Cs measurements, has attracted increasing attention in recent years as a means of obtaining spatially distributed information on rates of erosion and deposition. The application of the ¹³⁷Cs approach is, however, hampered in some areas of the world where ¹³⁷Cs inventories are low and the low concentrations of ¹³⁷Cs found in soils and sediments cause problems for laboratory analysis. These problems will increase as time progresses due to the radioactive decay of the existing inventory, most of which was deposited as fallout ca. 40 years ago. This contribution explores the potential for using another fallout radionuclide, namely unsupported ²¹⁰Pb, as an alternative to ¹³⁷Cs, in the small (63 km²) Upper Kaleya catchment in southern Zambia where ¹³⁷Cs inventories are already very low. The approach employed with unsupported ²¹⁰Pb is similar to that used for ¹³⁷Cs, although the essentially constant fallout of unsupported ²¹⁰Pb through time means that the resulting estimates of erosion and soil redistribution rates reflect a longer period of time (ca. 100 years rather than ca. 40 years). The estimates of erosion and deposition rates derived from the unsupported ²¹⁰Pb measurements are used to construct typical sediment budgets for the three main land-use types in the Upper Kaleya catchment, namely, commercial cultivation, communal cultivation and bush grazing. The results obtained from the unsupported ²¹⁰Pb are compared with equivalent results based on ¹³⁷Cs measurements provided by a previous investigation undertaken in the study catchment. The two sets of results are highly consistent. The study reported confirms the viability of using unsupported ²¹⁰Pb as an alternative to ¹³⁷Cs in this environment and demonstrates that conjunctive use of both radionuclides can provide additional information on the erosional history of a study area.     

Variability in soil redistribution in the northern Chihuahuan Desert based on Cesium measurements

A hypothesis for understanding the stability of northern Chihuahuan Desert landscapes is that the distribution of soil resources changes from spatially homogeneous in arid grasslands to spatially heterogeneous in invading shrublands. Since radioactive fallout ¹³⁷Cesium (¹³⁷Cs) was deposited uniformly across the landscape during the 1950s and 1960s and was quickly adsorbed to soil particles, any redistribution of ¹³⁷Cs across the landscape would be due to soil redistribution or instability at either plant-interspaces or on a landscape scale. The concentration of ¹³⁷Cs in soils collected from different vegetation communities (black grama grass, tarbush, tobosa grass, and mesquite) at the USDA-ARS Jornada Experimental Range in the Northern Chihuahuan Desert in New Mexico was determined. At the black grama grass and tobosa grass sites, ¹³⁷Cs was uniformly distributed at the plant interspace scale. At the mesquite sites, ¹³⁷Cs was concentrated in the dune area under mesquite shrubs with little to no ¹³⁷Cs in the interdune areas. ¹³⁷Cs data support the hypothesis that significant soil redistribution has occurred at dune sites created by invading mesquite. In the arid grassland-shrub sites with black grama grass, tobosa grass, and tarbush the ¹³⁷Cs data support the hypothesis of spatially homogeneous distribution of soil resources. High concentrations of ¹³⁷Cs in the biological soil crusts (0–5 mm) at the tarbush sites indicate that biological soil crusts can contribute to the stability of these sites.     

The role of soil erosion and fluvial processes in the post-fallout redistribution of Chernobyl-derived caesium-137: a case study of the Lapki catchment, Central Russia

The central area of the Russian Plain received substantial amounts Cs-137 fallout as a result of the Chernobyl accident in 1986, with inventories exceeding 40 kBq m⁻² in many of the areas close to Chernobyl. Concern over the longer-term fate of this contamination has focused attention on the need to predict the post-fallout redistribution of the radiocaesium and, thus, future changes in the spatial distribution of contamination in the landscape. Since radiocaesium reaching the land surface as fallout is rapidly and strongly adsorbed by soil and sediment particles, any attempt to predict its post-fallout redistribution must focus on erosion and sediment delivery processes and must rely heavily on a knowledge of the geomorphological processes involved. This paper reports a detailed investigation of post-fallout Cs-137 redistribution in the 2.18-km² Lapki catchment in the Middle-Russian Upland, which has required consideration of soil erosion processes, sediment delivery pathways, sediment delivery ratios and sediment sinks. The time elapsed since the Chernobyl accident is currently insufficient to result in significant reduction of Cs-137 inventories in eroding areas, but areas of deposition on both the lower slopes and on the balka sides and bottoms are already marked by significant increases in Cs-137 inventories. The results obtained emphasise that any attempt to develop meaningful predictions of the longer-term redistribution of Chernobyl-derived Cs-137 fallout within the Russian Plain must be based on a sound and detailed understanding of the linkage between the slopes and the balka systems and the fate of sediment entering the balka systems.     

~(137)Cs示踪法土壤侵蚀量估算的本底值问题

137Cs示踪法因能快速、相对简便地估算土壤侵蚀量而在土壤侵蚀定量研究中得到广泛应用。本底值获取是137Cs示踪法的关键和基础。在具有空间异质性多因素综合作用下,本底值呈现高度的空间异质性。针对本底值空间变异性,从气候气象要素、地形、土壤属性、土地利用/覆被四个方面阐明各因素与本底值空间变异的作用机理。分析了当前137Cs示踪法应用中在本底值获取时参考点存在性及选点的准确性、单个或几个本底值对研究区本底值的代表性和参考点采样设计。提出划分侵蚀测定单元、建立多本底值体系和进行地形校正解决当前137Cs示踪法中本底值存在问题的对策。侵蚀测定计算单元的划分原则和方法、根据已有参考点的137Cs本底值推算各单元137Cs本底值的技术方法、定量化研究各因素对137Cs的作用是今后需要深入的工作。     

Assessing Soil Remobilisation in Catchments using a 137Cs-sediment Hillslope Model

Soil redistribution studies are important, especially in water supply catchments, because the rate at which denudation is occurring has implications for offsite water quality. However, the extent to which soil is redistributed within the landscape can be difficult to determine. This challenge can be overcome using fallout caesium-137 (¹³⁷Cs). This paper describes the rates of soil loss and remobilisation in two sub-catchments within the Sydney Basin region, namely Kembla and Kentish Creeks, which drain to the Cordeaux reservoir. The total inventories of ¹³⁷Cs in catchment soils were determined, a ¹³⁷Cs-regression equation and a theoretical diffusion and migration model were used to established relationships between ¹³⁷Cs inventories and the rates of soil loss. These relationships revealed relatively low occurrence of soil loss in Kentish Creek, but two slopes in the Kembla Creek sub-catchment had losses that appear to be moderate. However, there was no clear evidence to suggest whether slopes in upper and lower reaches of catchments had specific patterns of soil remobilisation. Qualitative categorisation of the slope elements using a ¹³⁷Cs-sediment hillslope model can be a useful sentinel for land users and decision makers even if absolute rates of soil loss or gain are not certain. The findings suggest that sediments mobilised in the study sub-catchments are not likely to impact significantly on the water quality in the Cordeaux reservoir.     

Sediment focusing in six small lakes inferred from radionuclide profiles

Sediment focusing in six small lake basins is inferred from sedimentary radionuclide profiles. The activities of¹³⁷Cs and⁹⁺²⁴⁰Pu do not decrease to zero above the sub-surface maximum but tail off gradually. Similar behavior is observed in the sediments of three lakes for¹³⁴Cs and⁶⁰Co, which were added only to the lake. This upward tailing is not caused by bioturbation or erosion from the watershed. Sediment focusing is the likely cause, further substantiated by inventories in deep sediments of⁹⁺²⁴⁰Pu and²¹⁰Pb that are twice as high as expected from atmospheric fallout. Inventories in deep sediments of¹³⁷Cs are in several cases lower than expected from atmospheric fallout, and cannot be explained by hydraulic flushing from the lakes, as this would require unreasonable flushing rates. The low¹³⁷Cs inventories and the sedimentary profiles of the¹³⁷Cs/⁹⁺²⁴⁰Pu ratio are consistent with¹³⁷Cs removal from the water column by boundary scavenging to shallow sediments. The profiles and inventories of all three nuclides could be reproduced with a simple three box model, assuming focusing of shallow sediments (50–60% of total sediment area) to deep sediments with a rate constant of 5–10% yr^–1.This is the seventh of a series of papers to be published by this journal following the 20 ^th anniversary of the first application of²¹⁰Pb dating of lake sediment. Dr P. G. Appleby is guest editing this series.     

A model of Cs activity profile for soil erosion studies in uncultivated soils of Mediterranean environments

A model to simulate ¹³⁷Cs profiles in soils during the time in which they are being eroded is proposed. The model uses one parameter to characterize the cesium transference in the soil and another to express the erosion rate. To test the model, ¹³⁷Cs profiles of stable and eroded soils were collected at sampling sites located on semi-arid and temperate slopes in the Central Ebro basin, Spain. The ¹³⁷Cs profiles, corresponding to uncultivated soils with natural vegetation cover, were simulated using this model. The ¹³⁷Cs inventories and profiles calculated with the model are very similar to those measured experimentally, and thus it is possible to calculate soil erosion rates in physiographically diverse Mediterranean environments.     

Application of210Pb in soils

The spectroscopic measurement of soil samples is described.²¹⁰Pb data from a soil survey in western-Europe are briefly reviewed. The average²¹⁰Pb flux from the atmosphere, as determined from²¹⁰Pb _exc soil inventories, is 90 Bq m^–2a^–1. A simple one-dimensional box-chain model is described. The model simulates the vertical, post depositional transport of natural and fall-out radionuclides in the soil. Simulation of measured²¹⁰Pb _exc ,¹³⁴Cs,¹³⁷Cs, and²⁴¹Am soil profiles shows that mixing (bioturbation) is a very efficient transport mechanism. Lead seems to be strongly fixed to organic and clay particles. It is transported by the displacement of the organic and clay carrier substances. The mean residence time of lead, caesium, plutonium and americium in organic rich forest soils is in the order of 250–1000 years. An applicability study in investigate the use of²¹⁰Pb in erosion problems showed erosion rates from 60–180 g m^–2a^–1 on organic rich forest and meadow sites with 10°–25° slopes.This is the eighth of a series of papers to be published by this journal following the 20 ^th anniversary of the first application of²¹⁰Pb dating of lake sediments. Dr P. G. Appleby is guest editing this series.     

Evaluating the mobility of137Cs,239+240Pu and210Pb from their distributions in laminated lake sediments

Post-depositional mobility of¹³⁷Cs,^239+240Pu and²¹⁰Pb was assessed in six small lake basins by comparing sedimentary nuclide profiles with their known fallout history. Laminae couplets, when present, were determined to be varves because the¹³⁷Cs and^239+240Pu 1963 fallout peaks are present in laminae couplets corresponding to years 1962–1964. There is no evidence of mobility of²¹⁰Pb, because 1) mass accumulation rates based on²¹⁰Pb agree with those based on¹³⁷Cs and^239+240Pu peak depths and with those based on varve counts, and 2)²¹⁰Pb ages agree with varve ages. Significant mobility of¹³⁷Cs is evident from the penetration of¹³⁷Cs to depths 15–20 cm deeper than^239+240Pu. Deep penetration of¹³⁷Cs in spite of a sharp gradient below the peak is interpreted by a numerical model to suggest that¹³⁷Cs is present in two distinct forms in these sediments, 67–82% as an immobile form and 18–33% reversibly adsorbed with a K _d of approximately 5000. The profiles can be interpreted equally well assuming a small portionof the total¹³⁷Cs was present as an extremely mobile phase (K _d 5000) in the months to years following peak fallout, slowly becoming more strongly adsorbed. High NH ₄ ⁺ concentrations in porewaters may enhance diffusion of the mobile form of¹³⁷Cs, but not of the immobile form of¹³⁷Cs that defines the sharp gradient. Mobility of¹³⁷Cs is likely also enhanced by the low clay content and the high porosity of these sediments. Thus the first detection of¹³⁷Cs in the sediments cannot automatically be assumed to correspond to a date of 1952 (initial testing of thermonuclear weapons), although the depth of the peak can be assumed to correspond to 1963 (the year of maximum fallout from testing of thermonuclear weapons).^239+240Pu is a more reliable sediment chronometer than¹³⁷Cs because it is significantly less mobile.This is the sixth of a series of papers to be published by this journal following the 20 ^th anniversary of the first application of²¹⁰Pb dating of lake sediments. Dr P.G. Appleby is guest editing this series.     

Post-depositional 137Cs Mobility in the Sediments of Three Shallow Coastal Lagoons, SW England

We present ¹³⁷Cs profiles for three low lying coastal lagoons in Southwest England that show a decline in activity with sediment depth. ¹³⁷Cs inventories are lower than expected by comparison with local reference inventories despite the fact that sampling was undertaken in the deep-water zone of each lake where sediment and ¹³⁷Cs focusing would be expected. At all three locations, lake sediment ⁷Be and unsupported ²¹⁰Pb (²¹⁰Pb_un) inventories are not significantly lower than the local reference inventory. ¹³⁷Cs inventories in the study cores range from 38 to 95% of local reference inventories. The standing water level and mud: water interface at two sites are below maximum tide level and, at all three sites, salinity increases significantly in the water columns between low and high tide and in the pore waters of the underlying sediments. We suggest that the difference in hydrostatic pressure between sea level and standing water levels in the lagoons forces salt water up through the sediment column and that monovalent cations (especially Na⁺ and K⁺) replace ¹³⁷Cs on exchange sites leading to the upward migration and loss of ¹³⁷Cs. Rising sea levels may therefore contribute to remobilisation and release of ¹³⁷Cs to the aquatic environment from the sediments of coastal lagoons.     

Fallout radionuclide tracers identify a switch in sediment sources and transport-limited sediment yield following wildfire in a eucalypt forest

Fire can alter sediment sources and transport rates in river basins, changing landforms and aquatic habitats and degrading downstream water quality. Variability in the response between environments, between fires, and with time since fire makes predicting the catchment-scale effect of individual fires difficult. This study applies the fallout radionuclides ¹³⁷Cs and ²¹⁰Pb_xs to trace the sources and transport of fine sediment through a river network following a wildfire of moderate to extreme severity in the 629-km² eucalypt-forested Nattai River water-supply catchment near Sydney, Australia. The tracer analysis showed that post-fire erosion caused a switch in fine (< 10 µm) sediment sources from 80% subsoil derived from gully and river bank erosion to 86% topsoil derived from hillslope surface erosion. The fine sediment phosphorus content increased 4–10 fold over pre-fire levels. Annual post-fire sediment yields estimated from suspended solids rating curves were 109–250 times higher than they would have been without fire. A large additional amount of sediment remained stored within the river network for at least four years, particularly in lower-gradient reaches. Analysis of a sediment core showed that surface erosion following a previous fire had supplied at least 29% of total catchment sediment yield over the past 36 years. It is concluded that wildfire can alter catchment sediment budgets in two ways. Firstly, a spatially-diffuse pulse of elevated erosion is associated with moderate or intense rainfall events in post-fire years. Secondly, pulses of elevated catchment sediment yield are driven by the timing and river sediment transport capacity of runoff events. Severe post-fire erosion and high interannual hydrologic variability can result in large sediment stores persisting within the river network for many years. Fallout radionuclide tracers are shown to be useful in quantifying fine sediment sources and transport dynamics following wildfire, and the contribution of wildfire to catchment sediment yield.     

The transport and mass balance of fallout radionuclides in Blelham Tarn, Cumbria (UK)

Although lake sediment archives are widely used for reconstructing historical records of atmospherically delivered pollutants, the quantitative relationship between fallout levels and their record in the sediments is complex and not well known. The original input signal from the atmosphere can be significantly distorted by mediating transport processes in the catchment, through the water column and within the sediments themselves. Since these processes also affect the fallout radionuclide ²¹⁰Pb commonly used to date sediments, a better understanding of their impact is also important to improving the accuracy and reliability of sediment dating. Blelham Tarn has been the subject of a number of palaeolimnological investigations using radiometric dating techniques since the early 1970s. More recently it was the site of a major study carried out within the EU Transuranics project concerning the long-term fate of fallout radionuclides in catchment/lake systems. This paper reviews the radiometric data from this study and uses the results to determine mass balances for fallout ²¹⁰Pb, ¹³⁷Cs and ^239+240Pu in Blelham Tarn, and their spatial distribution over the bed of the lake. Atmospheric fluxes were determined by measuring concentrations in rainwater and cumulative inventories in soil cores from non-eroding sites. Sediment records in a grid of 16 cores were used to determine the spatial distribution over the bed of the lake, and net inputs from the catchment. Mass balance calculations indicate that c. 47% of ²¹⁰Pb in the sediments derives from erosive inputs from the catchment. For ^239+240Pu the figure rises to 61%. Reduced amounts of ¹³⁷Cs in the sediments are attributed to greater losses of this radionuclide from the water column via the outflow due to its greater solubility. Inputs of radionuclides from the catchment are concentrated near one of the major input streams. Away from this part of the lake the sediment record is dominated by direct atmospheric fallout, though the detailed pattern is influenced by sediment focussing. A one parameter catchment/lake transport model is developed that incorporates the assumption that transport rates will decline with time as fallout on the catchment diffuses into the soil and becomes less available for removal. Values of the transport parameter were calculated for ²¹⁰Pb and ^239+240Pu and found to be comparable. The results suggest that it will take c. 11000 years to remove 50% of ^239+240Pu from the catchment to the lake.     

Environmental Change and Atmospheric Contamination on Svalbard: Sediment Chronology

Sediment cores collected from eight lakes along the western coast of Svalbard as part of a project investigating atmospheric pollution and environmental change in Arctic regions were dated radiometrically using natural (²¹⁰Pb) and artificial (¹³⁷Cs and ²⁴¹Am) fallout radionuclides. At four sites the sedimentation rates were relatively uniform, and in consequence the ²¹⁰Pb dates were relatively unambiguous. At the remaining sites there were irregularities in the ²¹⁰Pb activity versus depth profiles, indicating significant variations in the net sediment accumulation rate during the past 120 years. At these sites, there were significant differences between ²¹⁰Pb dates calculated using the two standard simple dating models, constant rate of supply (CRS) and constant initial concentration (CIC). In most cases, stratigraphic dates based on the ¹³⁷Cs and ²⁴¹Am records supported use of the CRS model, though at one site (Ossian Sarsfjellet) the CIC model appeared more appropriate. The irregularities in the ²¹⁰Pb records were mainly caused by episodes of accelerated sedimentation due, for example, to inwash or slump events, though at some sites there appears to have been a systematic increase in sediment accumulation rates in recent decades. Sediment accumulation rates were generally lower at the northern sites, and higher at the more southerly locations. Mean sediment accumulation rates varied by an order of magnitude, ranging from 0.002 to 0.050 g cm⁻² y⁻¹ (0.02–0.10 cm y⁻¹). ²¹⁰Pb fluxes measured from the core inventories were mostly in the range 34–80 Bq m⁻² y⁻¹ typical of Arctic sites. Much higher values, recorded at two sites (Birgervatnet and Daltjørna), may be due to significant inputs from the catchments during spring thaw.     

Chernobyl radiocaesium in upland watershed-lake systems,Galloway, south west Scotland

Levels of Chernobyl radiocaesium found in the upland region of Galloway, south west Scotland were relatively high e.g. catchment mean¹³⁴Cs inventories ranged from 5.72±2.64 kBq m² to 8.72±1.46 kBq m². The nuclear weapons test¹³⁷Cs content of soils and peats was significantly augmented. Accurate assessment of spatial variations and temporal changes in the levels of contamination, however, are inhibited by its marked, short-range heterogeneity. No significant change in mean catchment inventories was detected over a twelve month period. Lake sediment inventories, however, were consistently enhanced from initially lower levels of contamination than their catchments' surfaces. Pre Chernobyl catchment and lake sediment¹³⁷Cs inventories, however, show no such contrast. Both are substantially lower than rainfall based predictions. These observations of the relative levels of Chernobyl and pre-existing radiocaesium in watersheds and their waterbodies have important implications for both the assessment of the catchment and lake residence times of particle-associated contaminants and the use of lake sediment records as monitors of such pollutants.     

黑土侵蚀速率及其对土壤质量的影响

利用¹³⁷Cs示踪法,研究了东北黑土耕作土壤的流失厚度和速率,探讨了水土流失对土壤机械组成、有机质、土壤水分、容重及其N、P含量的影响。结果表明:研究区侵蚀坡面¹³⁷Cs的分布深度在0～25cm,¹³⁷Cs的活度在1246.05±85.90～1499.45±101.73Bq/m²,侵蚀厚度可达0.316～0.433mm/a,侵蚀强度3033.6～3940.3t/km²·a,已属于中度侵蚀水平。水土流失造成土壤质地粗化,从坡顶向坡底,耕层土壤有机质增加、容重变化不大,含水量增加,土壤养分的“贫化”现象明显。     

滇西和黔中表土中7Be与137Cs分布特征对比研究

滇西和黔中28个表土剖面分层土样^7Be、^137Cs比活度对比分析可见：滇西地区表土层顶部^7Be/^137Cs为100－1000，而黔中地区仅10－100；两地区表土层中^7Be的表观比活度和最大渗透深度总体相近；^137Cs在黔中表土层中的比活度总体较滇西地区略高。而黔中表土中^7Be累计值的偏低现象，映射了该地区强烈的水土流失。为解释滇西和黔中地区之间表土层顶部^7Be/^137Cs的地区差异，需进一步讨论两核素的湖泊沉积物蓄积特征。     

Anthropogenic radionuclides in the water column and a sediment core from the Alboran Sea: application to radiometric dating and reconstruction of historical water column radionuclide concentrations

Global fallout is the main source of anthropogenic radionuclides in the Mediterranean Sea. This work presents ¹³⁷Cs, ^239+240Pu and ²⁴¹Am concentrations in the water column in the southwest Alboran Sea, which was sampled in December 1999. A sediment core was taken at 800 m depth in the area (35°47′ N, 04°48′ W). ²¹⁰Pb, ²²⁶Ra, ¹³⁷Cs and ^239+240Pu specific activities were measured at multiple depths in the core for dating purposes. ¹³⁷Cs and ^239+240Pu profiles did not show defined peaks that could be used as time markers, and they extended up to depths for which the ²¹⁰Pb-based constant rate of supply (CRS) dating model provided inconsistent dates. These profiles can be useful to test dating models, understood as particular solutions of a general advection–diffusion problem, if the time series of radionuclide inputs into the sediment is provided. Thus, historical records of depth-averaged ¹³⁷Cs and ^239+240Pu concentrations in water, and their corresponding fluxes into the sediment, were reconstructed. A simple water-column model was used for this purpose, involving atmospheric fallout, measured distribution coefficient (k _d) values, and a first-estimate of sedimentation rates. A dating model of constant mixing with constant sedimentation rate was applied successfully to three independent records (unsupported ²¹⁰Pb, ¹³⁷Cs and ^239+240Pu), and provided the objective determination of mixing parameters and mass sedimentation rate. These results provide some insight into the fate of atmospheric inputs to this marine environment and, particularly, into the contribution from the Chernobyl accident.     

放射性核素137Cs在示踪土壤侵蚀研究中的应用

近几十年来,土壤侵蚀日益加剧,伴随着土地质量的退化,已成为影响区域可持续发展的主要环境问题。利用放射性核素137Cs进行土壤侵蚀研究能够简便、快速、准确地获取土壤流失、沉积和空间重新分布等详细信息。从元素来源、空间分布、背景值、示踪原理、活度测定、转换模型等方面对该方法进行了详细描述,在总结其优缺点的基础上,对其未来的发展方向做出了展望。