Application of Chernobyl-derived Cs for the assessment of soil redistribution within a cultivated field

Vast areas of Europe were contaminated by the Chernobyl-derived ¹³⁷Cs in April–May 1986. This paper reports a detailed study of the post-fallout ¹³⁷Cs redistribution within a 1 ha field located in the Chasovenkov Verh catchment in the northern part of the Middle-Russian upland. Particular attention was paid to the study of reference inventories. It is shown that the random spatial variability of ¹³⁷Cs is similar within undisturbed and cultivated parts of a flat interfluve. Systematic spatial variability is not essential for a relatively short (200 m) topographical unit with simple relief. The analysis of a soil redistribution pattern within the study field using the Chernobyl ¹³⁷Cs technique demonstrates that it is possible to identify areas of soil loss/gain. This pattern does not reflect soil redistribution for the whole field, because these have been only 12 years since the Chernobyl accident. Net erosion rates based on ¹³⁷Cs method were comparable to soil losses directly measured at the study field.     

Caesium-137 fallout depth distribution in different soil profiles and significance for estimating soil erosion rate

Caesium-137 (¹³⁷Cs) has been widely used for the determination of soil erosion and sediment transport rate. However, depth distribution patterns of ¹³⁷Cs in the soil profile have not been considered. As a result, the erosion rates may be over-estimated or underestimated. This paper presents the depth distribution of ¹³⁷Cs fallout in different soil profiles using published data. Three types of depth distribution functions of ¹³⁷Cs are given by using statistical regression methods, the exponential type, the peak type and the decreasing type (including uniform distribution). Relationships between ¹³⁷Cs loss and soil erosion rate are given by introducing the regression functions. The influence of depth distribution of ¹³⁷Cs on the estimation of the soil erosion rate was simulated. Simulation results showed that very different soil erosion rates could be deduced for different depth distributions when ¹³⁷Cs loss is the same, which indicates that the depth distribution pattern should be considered when soil erosion is estimated by using ¹³⁷Cs. Simulation results also suggested that it is most important to determine the depth distribution of ¹³⁷Cs near the soil surface and the annual relative loss of ¹³⁷Cs by using the depth distribution of ¹³⁷Cs as a criterion to estimate the soil erosion rate.     

水稻对~(137)Cs的叶面吸收

水稻不同生育期污染主茎单个叶片结果表明,１３７Ｃｓ向植株未污染部位的转移与污染叶的叶位有关,植株中的１３７Ｃｓ主要分布在茎叶中。受污染的水稻各部位１３７Ｃｓ积累量与污染量呈线性正相关,植株各未污染部位１３７Ｃｓ比活度大小顺序为叶＞茎＞根＞穗。     

红壤侵蚀沉积点^137Cs垂直剖面分布特征

研究了红壤农田和荒地侵蚀沉积点中 1 3 7Cs的剖面分布特征 ,结果表明 ,沉积点在 1 7cm处有明显的峰谷 ,农田沉积点 1 3 7Cs含量要高于荒地 ;经估算 ,两沉积点的沉积速率相近 ,1 96 3年以来为 1 .0 3 cm/ a,近 2 0年约为 0 .74cm/ a;沉积点的 1 3 7Cs分布显示该区域侵蚀有减小的趋势 ;1 3 7Cs活度与有机质存在较好的相关性 ;1 3 7Cs在侵蚀研究中具有重要意义     

坡耕地土壤侵蚀对土壤化学性质的影响

运用 137 Cs示踪了陕北安塞试区坡耕地土壤侵蚀量,并以室内分析的方法研究了黄土高原 北部坡耕地土壤侵蚀与土壤性状的关系。研究结果表明,黄土高原坡耕地土壤侵蚀量在 山坡中、上 部是侵蚀最严为强烈的地带,而在坡顶侵蚀较弱,在坡下有土壤堆积;土壤全N、碱解N和 速效K 与水蚀及耕作侵蚀成线性相关;有机质、速效P、阳离子代换量及土壤质地则与水蚀及耕 作侵蚀无 显著相关。     

立体生态净化床处理含锶、铯废水的试验研究

[目的]利用立体生态净化床处理含锶、铯废水。[方法]分别采用种植吉祥草、吊兰、水花生、吊竹梅、凤眼莲的立体生态净化床系统,对含锶、铯废水的净化效果进行了试验研究。[结果]不同植物系统对含锶、铯废水净化效果各不相同,吉祥草、吊兰、水花生、吊竹梅、凤眼莲系统对水体中Sr的最终去除率分别为48.7%、46.1%、38.8%、45.8%和31.7%;对Cs的最终去除率分别为60.0%、56.7%、45.0%、42.1%、20.3%。其中,以种植吊兰的生态净化床处理效果最好,地上部对Sr、Cs的富集量分别为223.54和18.63 mg/kg,可作为后期研究对象。[结论]该研究为含锶、铯废水的处理提供了科学参考。     

Using caesium-137 measurements to investigate soil erosion rates in western Istanbul (NW Turkey)

Buyukcekmece Reservoir, located in the western outskirts of Istanbul, is one of the major water resources of Istanbul, and supplies drinking water to about 4 million people. Erosion in the catchment of the reservoir is an important problem in terms of its longer-term sustainability for water supply. There is an urgent need to obtain reliable quantitative data regarding erosion and deposition rates within the catchment to assess the magnitude of the problem and to plan catchment management strategies. In the absence of existing data, attention has focussed on the potential for using ¹³⁷Cs measurements to provide retrospective estimates of medium-term soil erosion rates within the catchment over the past ca. 40 years. To date, the ¹³⁷Cs approach has not been used to document soil redistribution rates in Turkey and this contribution reports an attempt to confirm the viability of the approach and the results of a preliminary investigation of rates of soil loss from uncultivated areas within the catchment. The soil redistribution rates estimated using the profile distribution conversion model varied from − 16.11 (erosion) to 4.59 (deposition) t/ha/year.     

黄土丘陵区水平梯田保水保土效益分析

水平梯田是防止水土流失的一种有效方式。在韭园沟流域的支沟——王茂沟流域分别选取梯田和坡耕地进行土壤采样,测定土壤含水量,结合¹³⁷Cs示踪,对比分析了梯田长期的保水保土效益。结果表明:梯田土壤水分变化分为土壤水分剧变层（0—20 cm）、土壤水分活跃层（20—30 cm）和土壤水分调节层（30 cm以下）;梯田不同深度土壤含水量均表现为内侧（第一级） > 中部 > 外侧（第五级）;坡向对梯田土壤水分的影响并不是十分显著;梯田0—20 cm土壤蓄水量高于坡耕地7.2%;0—40 cm平均土壤蓄水量高出坡耕地1.8 mm;研究流域坡耕地与梯田侵蚀程度分别属于极强度侵蚀和强度侵蚀,梯田平均水土保持效益为53%。建议在该地区修建梯田时,提高梯田的设计标准,对梯田田面、田埂认真维护,实现梯田长期的水土保持效益。     

Using Cs‐137 fingerprinting technique to estimate sediment deposition and erosion rates from Yongkang depression in the karst region of Southwest China

Understanding the erosion and deposition rates is very important for designing soil and water conservation measures. However, existing methods of assessing the rates of soil loss present many limitations and are difficult to apply to in karst areas, and there is still very little data in this areas. Karst depressions comprise geomorphologically important sources and sinks for sediments and can provide the long‐term history records of environmental changes. But there have been few similar studies focused on its sediments in the world. In this paper, the Cs‐137 technique was employed to estimate the sediment deposition rate of karst depression to assess the surface erosion. The results indicate that the average deposition rate, deposition amount and specific deposit yield for the Yongkang catchments since 1963 were estimated to be 4·32 mm y⁻¹, 3·16 t y⁻¹and 20·53 t km⁻² y⁻¹, respectively. The results obtained were consistent with the actual monitoring data of local runoff plots, and confirm the validity of the overall approach. So it was suggested that the mean specific sediment yields of 20 t km⁻² y⁻¹ can be representative of the soil loss rates in the regions. Copyright © 2010 John Wiley & Sons, Ltd.     

沂蒙山区土壤侵蚀的137Cs示踪法初步研究

沂蒙山区是我国北方典型的土石山区,当地土壤由片麻岩、砂岩发育而来,质地疏松易流失,缺乏对泥沙侵蚀监测的长期观测数据。本研究采集了山东省沂蒙山区某一小流域的48个土样共72个样品,利用137Cs示踪技术,确定该地区土壤中的137Cs背景值约为1 740 Bq m-2,并利用杨浩等人的土壤侵蚀定量模型,对该流域土壤侵蚀进行了初步估算。估算结果表明该地区非耕地土壤侵蚀的平均速率为2 531 t km-2a-1,坡耕地土壤侵蚀的平均速率为6 953 t km-2a-1。由于人类耕作活动以及地形的影响,坡耕地土壤侵蚀严重,土壤侵蚀速率在坡面上呈复杂变化。当地土壤流失严重,使得土壤涵蓄水能力下降,加剧了洪涝、干旱灾害的发生,影响当地农业的可持续发展和人们生活水平的提高。