基于 GIS和USLE/RUSLE的小流域土壤侵蚀量研究

依据实地调查资料,建立了典型小流域地理数据库;应用采样分析数据结果及坡面单元法,确定了定量计算通用土壤流失方程RUSLE因子指标的方法.在地理信息系统ArcGIS支持下,根据USLE/RUSLE土壤侵蚀预测模型对数据库实施运算操作,预测了小流域土壤侵蚀量.结果表明:①流域总体土壤侵蚀为中度,治理难度仍很大;②坡耕地是流...     

城市路边沉积物中Pb、Cu污染调查与评价

对连云港市商业区路边沉积物中Pb和Cu的含量及污染程度进行了调查。结果表明,连云港市商业区路边沉积物中Pb的算术平均值为97．24mg／kg。是我国A层土壤算术平均值的3．7倍,沉积物中Cu的算术平均值为49．99mg／kg。是我国A层土壤算术平均值的2．24倍;沉积物中Cu含量分布变异性比Pb含量高。地累积指数的评价结果表明,沉积物中Pb比Cu污染严重。     

超高效液相色谱-串联质谱法分析土壤及沉积物中氨基甲酸酯农药

利用超高效液相色谱-串联质谱,建立土壤和沉积物中痕量氨基甲酸酯农药的分析方法。该方法用体积比1:1的二氯甲烷/甲醇对土壤和沉积物样品进行加速溶剂萃取,GCB/PSA固相萃取小柱对萃取液进行净化,内标法定量,用超高效液相色谱-串联质谱法分析土壤和沉积物中20种氨基甲酸酯农药。20种氨基甲酸酯农药在0.02~1.0 μg/mL范围内线性良好(r≥0.99),检测限为0.20~0.60 ng/g。沉积物加标样品(20ng/g)和土壤加标样品(20ng/g)的回收率分别为33.2%~101.9%、38.8%~120.5%,相对标准偏差为6.1%~28.0%、2.3%~16.0%。沉积物加标样品(2.0 ng/g)回收率为43.0%~100.0%,相对标准偏差为2.1%~11.3%。     

异丙醇增感电感耦合等离子体质谱法直接测定土壤和沉积物中硒

提出了沸水浴混合酸法消解,以异丙醇为增感剂,电感耦合等离子体质谱直接测定土壤和沉积物中硒的方法。实验表明2mol/L硝酸-4mol/L盐酸混酸能有效溶出土壤和沉积物中各种形态的硒。相对于1%硝酸基体,4%(V/V)异丙醇基体中硒的ICP-MS响应值提高了12.1倍;而且4%(V/V)异丙醇基体可有效抑制硒的质谱干扰。ICP发射功率和雾化气流速是影响异丙醇在ICP-MS测定过程增敏效应的主要因素。以78硒为测定同位素,方法检出限为0.005mg/kg,实际样品测定精密度均小于5%。用于测定土壤和沉积物国家标准样品并对其消解液进行加标回收实验,结果令人满意。     

长江南京段近岸沉积物和土壤中重金属分布特征分析

通过测定沉积物和土壤中Cd、Pb、Cr、Zn、Cu、Ni 6种重金属元素的平均含量,计算其富集因子,分析长江南京段近岸沉积物和土壤中重金属的空间分布特征,结果表明,几种重金属在沉积物中的富集次序为:CdPbCr1NiCuZn,在土壤中为:CdZnCu1CrPbNi,除Zn和Cu外,其他几种金属在沉积物中的富集程度高于土壤,同时Cd的含量超过土壤环境质量三级标准。以Cd和Pb为例分析了重金属含量与沉积物粒级之间的关系,回归分析显示,Cd、Pb的含量与颗粒物的粒级呈显著的相关性,与细颗粒物的含量有密切关系,细颗粒携带的重金属,在长江水力分选作用下到达下游,成为沉积物中重金属的主要来源。     

基于环境磁学响应监测林地土壤中金属元素

采集并测试广州市林地土壤样品600余组,分析土壤中As、Cr、Cd、Hg、Cu、Pb、Zn、Ni和磁学性质的相关性。结果表明：土壤磁性颗粒以软磁性矿物为主,北部以超顺磁、多畴颗粒为主,南部以单畴、多畴颗粒为主。相关性分析表明：北部Cu、Ni、Cr、Cd与较粗的磁性颗粒共存,Cd与软磁性矿物共存,As与超顺磁颗粒共存且为自然源;南部相关关系不显著,Ni和As来源为人为源;不同污染程度土壤回归方程相关系数均较好,南部深〖CD*2〗浅层回归方程证明上述8种元素和磁性相关性不受自然来源或人类活动影响。     

山美水库流域表层沉积物中DDTs农药的残留特征及风险评估

利用GC-ECD检测了山美水库流域表层沉积物中DDTs农药含量,分析了其残留与组成特征及生态风险.结果表明,表层沉积物中DDTs平均含量为4.07 ng/g,其含量范围为0.96～8.20 ng/g;DDTs含量大小顺序为桃溪与湖洋溪汇流(8.20 ng/g)>湖洋溪(4.67 ng/g)>桃溪(4.59 ng/g)>山美水库(1.96 ng/g).表层沉积物中新的DDTs输入量比较少;沉积物中DDTs主要来自于早期残留或是施用农药长期风化后的土壤;大多数采样点DDTs发生好氧生物降解,降解产物以DDE为主.对照Ingersoll风险评估标准,表层沉积物中DDTs农药残留具有较高的生态风险.     

环境样品中 PCBs 的测定

通过碱解、酸洗、萃取、净化、浓缩、脱硫等步骤处理实际样品,利用毛细管柱GC/ECD进行PCBs的定性和定量.方法定性准确,定量良好,具有较高的回收率.各同系物的方法检出限,水样为0.01～0.08ng/L;土壤样为0.003～0.03μg/kg,可以应用于土壤、沉积物、水样、油样等环境样品中PCBs的测定     

使用全扫描和选择离子扫描两种方式建立土壤和沉积物中16种多环芳烃的气相色谱四级杆质谱联用仪分析方法

文章建立气相色谱四级杆质谱联用分析土壤和沉积物中16种多环芳烃的测定方法。参考《土壤和沉积物多环芳烃的测定气相色谱质谱法》(HJ805-2016)和《全国土壤污染状况详查土壤样品分析测试方法技术规定》采用全扫描和选择离子扫描两种方式优化定性、定量分析步骤。结合实际对土壤和沉积物中多环芳烃进行了加压流体萃取(ASE)的提取和GPC净化方式,建立了土壤和沉积物中16种多环芳烃的气相色谱四级杆质谱联用仪分析方法。     

液相色谱-串联质谱法测定水体、沉积物及土壤中全氟化合物

建立了水、沉积物及土壤中13种全氟化合物(PFCs)的富集、净化、浓缩的前处理方法及快速液相色谱三重四级杆串联质谱的分析方法。9种全氟羧酸、2种典型全氟磺酸、2种磺酰铵衍生前体物的响应因子与质量浓度的线性关系良好。添加回收实验表明,13种全氟化合物在水、土壤和沉积物中的回收率为52.3%~119.3%,变异系数为2.3%~19.4%,方法检出限分别为0.015~0.472 ng/L、0.012~0.875 ng/g、0.004~0.743 ng/g。该法成功应用于实际样品的测定,沉积物和土壤中分别检测到3种和10种全氟化合物。     

Check dam sediments: an important indicator of the effects of environmental changes on soil erosion in the Loess Plateau in China

Check dam sediments document the process of soil erosion for a watershed. The main objectives of this research are as follows: first, to determine whether the sediments trapped in check dams can provide useful information about local erosion and the environment, and second, to obtain the extent to which they can be stratigraphically interpreted and correlated to the land use history of an area controlled by check dams. Particle size and the concentration of ¹³⁷Cs in sediments are the indicators used to study the effects of environmental changes on soil erosion in the Loess Plateau, China. A total of 216 soil samples were collected from four sediment profile cores at the Yangjuangou watershed check dam constructed in 1955 and fully silted with sediments by 1965. The results indicated that ¹³⁷Cs dating and sediment particle size can characterize the sediment deposition process. Silt makes up more than 50 % of the sediment; both the clay and silt sediment fractions decrease gradually in the upstream direction. The sediment profiles are characterized by three depositional layers. These layers suggest changes in the land use. The top layer showed tillage disturbance, with moderate sediments and new soil mixed from 0 to 20 cm. A transition stage from wetlands (characterized by vegetation such as bulrush) to cropland is inferred from sediments at depths of 20–85 cm. Below 85 cm, sedimentary layering is obvious and there is no tillage disturbance. At the downstream site, A0, the average rate of sediment deposition from 1958 to 1963 was approximately 6,125.4 t year^?1 km^?2. Because of their high time resolution, check dam sediments indicate the effects of environmental changes on soil erosion, and they can provide a multiyear record of the soil erosion evolution at the local scale in the middle reaches of the Yellow River.     

Nitrogen enrichment in runoff sediments as affected by soil texture in Beijing mountain area

Enrichment ratio (ER) is widely used in nonpoint source pollution models to estimate the nutrient loss associated with soil erosion. The objective of this study was to determine the ER of total nitrogen (ER_N) in the sediments eroded from the typical soils with varying soil textures in Beijing mountain area. Each of the four soils was packed into a 40 by 30 by 15 cm soil pan and received 40-min simulated rainfalls at the intensity of 90 mm h^?1 on five slopes. ER_N for most sediments were above unity, indicating the common occurrence of nitrogen enrichment accompanied with soil erosion in Beijing mountain area. Soil texture was not the only factor that influenced N enrichment in this experiment since the ER_N for the two fine-textured soils were not always lower. Soil properties such as soil structure might exert a more important influence in some circumstances. The selective erosion of clay particles was the main reason for N enrichment, as implied by the significant positive correlation between the ER of total nitrogen and clay fraction in eroded sediments. Significant regression equations between ER_N and sediment yield were obtained for two pairs of soils, which were artificially categorized by soil texture. The one for fine-textured soils had greater intercept and more negative slope. Thus, the initially higher ER_N would be lower than that for the other two soils with coarser texture once the sediment yield exceeded 629 kg ha^?1.     

Classification of alluvial soils according to their potential environmental risk: a case study for Belgian catchments

Alluvial soils may represent important sinks of contaminants as a result of the deposition of contaminated sediments along the river by overbank flooding or after dredging. Because of the erosion of alluvial deposits or the release of contaminants from sediments, alluvial soils can also be a source of contamination. In this paper, a risk assessment for contaminated (alluvial) soils is presented. The approach, mainly based on physico-chemical soil characteristics, single extractions and leaching tests, is illustrated by means of a case study from four Belgian catchments. The extractions and leaching tests that were used have been validated by European testing programs and can provide valuable information for classifying the potential environmental risks of soils. Irrespective of the location, pH, organic carbon content and 'mobilisable' metal concentrations were the most important factors explaining 'mobile' metal concentrations in the alluvial soils. Additionally, the data of the physico-chemical soil characterization, extractions and leaching tests were combined with local and regional factors to classify the alluvial soils in different categories according to their actual and potential risk for the environment.     

环境磁学在城市地表灰尘重金属污染研究中的应用

随着环境问题日渐突出,地表灰尘重金属污染日益成为研究热点。单纯采用化学方法监测重金属污染具有一定局限性,环境磁学方法以其简便、快捷、经济且无害化的特点在城市重金属污染研究中广为应用。通过文献调研,综述环境磁学在城市地表灰尘重金属污染研究中的应用与研究进展,阐明重金属的主要来源,简述环境磁学的诸多参数,分析磁学参数与重金属的关系,并通过对比不同的磁学分析方法,探讨环境磁学方法在城市地表灰尘重金属污染研究中存在的问题及其发展趋势。     

城市环境中磁学响应的研究进展

利用磁学方法研究城市环境中重金属元素的污染受到普遍关注和重视。比较系统地探讨了城市环境中磁性矿物的来源和特征,阐述了城市环境磁学的研究内容,探讨了城市磁学研究的发展趋势,强调了运用简便、经济的磁学方法研究城市环境中重金属等污染物是今后环境磁学的一个重要的发展方向。     

环境磁学在重金属污染研究中的应用

20世纪60年代以来,环境磁学以快速、灵敏、经济、无破坏性和信息量大等特点被广泛应用到环境污染研究中。笔者介绍了环境磁学应用于重金属污染监测的基本原理和优势,系统综述了其在大气,水体(湖泊、河流和海岸等)和土壤等环境重金属污染监测中的主要成果和最新进展,包括磁学参数可作为重金属污染物质代用指标,以及环境磁学在重金属污染分布特点和污染程度鉴定、重金属污染历史重建、重金属污染物运移追踪等方面的应用。提出了重金属污染磁性诊断研究还需要解决的问题,包括磁学参数多解性,其他环境过程(动力分选、吸附解吸和早期成岩等)的干扰和影响,磁性矿物与重金属物质赋存关系及多学科交叉研究等。     

The Environmental Implications of Soil Erosion in the United States

Soil erosion has both on-farm and off-farm impacts. Reductionof soil depth can impair the lands productivity, and thetransport of sediments can degrade streams, lakes, and estuaries. Since 1933, soil conservation policies have existedin the United States. Originally they focused on the on-farmbenefits of keeping soil on the land and increasing net farmincome. Beginning in the 1980s, however, policy goalsincreasingly included reductions in off-site impacts of erosion.As a consequence of conservation efforts associated withexplicit U.S. government policies, total soil erosion between1982 and 1992 was reduced by 32% and the sheet and rillerosion rate fell from an average of 4.1 tons per acre per yearin 1982 to 3.1 tons per acre in 1992 while the wind erosion ratefell from an average of 3.3 tons per acre per year to 2.4 tonsper acre per year over the same period. Still, soil erosion isimposing substantial social costs. These costs are estimated tobe about $37.6 billion annually. To further reduce soil erosionand thereby mitigate its social costs, there are a number ofpolicy options available to induce farmers to adopt conservationpractices including education and technical assistance, financial assistance, research and development, land retirement, andregulation and taxes.     

Assessing the effects of land use changes on soil sensitivity to erosion in a highland ecosystem of semi-arid Turkey

There has been increasing concern in highlands of semiarid Turkey that conversion of these systems results in excessive soil erosion, ecosystem degradation, and loss of sustainable resources. An increasing rate of land use/cover changes especially in semiarid mountainous areas has resulted in important effects on physical and ecological processes, causing many regions to undergo accelerated environmental degradation in terms of soil erosion, mass movement and reservoir sedimentation. This paper, therefore, explores the impact of land use changes on land degradation in a linkage to the soil erodibility, RUSLE-K, in Cankiri–Indagi Mountain Pass, Turkey. The characterization of soil erodibility in this ecosystem is important from the standpoint of conserving fragile ecosystems and planning management practices. Five adjacent land uses (cropland, grassland, woodland, plantation, and recreational land) were selected for this research. Analysis of variance showed that soil properties and RUSLE-K statistically changed with land use changes and soils of the recreational land and cropland were more sensitive to water erosion than those of the woodland, grassland, and plantation. This was mainly due to the significant decreases in soil organic matter (SOM) and hydraulic conductivity (HC) in those lands. Additionally, soil samples randomly collected from the depths of 0–10 cm (D ₁) and 10–20 cm (D ₂) with irregular intervals in an area of 1,200 by 4,200 m sufficiently characterized not only the spatial distribution of soil organic matter (SOM), hydraulic conductivity (HC), clay (C), silt (Si), sand (S) and silt plus very fine sand (Si + VFS) but also the spatial distribution of RUSLE-K as an algebraically estimate of these parameters together with field assessment of soil structure to assess the dynamic relationships between soil properties and land use types. In this study, in order to perform the spatial analyses, the mean sampling intervals were 43, 50, 64, 78, 85 m for woodland, plantation, grassland, recreation, and cropland with the sample numbers of 56, 79, 72, 13, and 69, respectively, resulting in an average interval of 64 m for whole study area. Although nugget effect and nugget effect–sill ratio gave an idea about the sampling design adequacy, the better results are undoubtedly likely by both equi-probable spatial sampling and random sampling representative of all land uses.     

Adapting the RUSLE and GIS to model soil erosion risk in a mountains karst watershed, Guizhou Province, China

Soil erosion is a serious environmental problem in Guizhou Province, which is located in the centre of the karst areas of southwestern China. Unfortunately, Guizhou Province suffers from a lack of financial resources to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Maotiao River watershed, which is a typical rural watershed in Guizhou Province. All factors used in the RUSLE were calculated for the watershed using local data. It was classified into five categories ranging from minimal risk to extreme erosion risk depending on the calculated soil erosion amount. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The results can be used to advice the local government in prioritizing the areas of immediate erosion mitigation. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion. It thus indicates that RUSLE-GIS model is a useful and efficient tool for evaluating and mapping soil erosion risk at a large watershed scale in Guizhou Province.     

Soil Erosion Potential after Fire and Rehabilitation Treatments in Greece

Wildland fires are one of the more severe disturbances for natural ecosystems in the Mediterranean basin and can become a critical factor in the process of soil erosion. A quantitative assessment of soil erosion is needed in order to form an assessment on the extent and magnitude of post-fire soil erosion potential and to assess the effectiveness of the rehabilitation treatment. On 21 August 2006, a large wildland fire occurred in the Kassandra Peninsula in northern Greece, which burned one fifth of the Peninsula. After the fire, in order to protect the soil against erosion, the Forest Services applied a hillslope rehabilitation treatment of contour-felled logs and branch piles. In this paper, we report quantitative estimation of the wildland fire and erosion control treatment on soil erosion potential. The coupling of the Universal Soil Loss Equation and the Geographical Information Systems was implemented and the erosion potential was found to be 2.8 t/ha/year pre-fire, 29.5 t/ha/year post-fire, and 21.3 t/ha/year after rehabilitation treatment. The model can successfully contribute in the planning of the rehabilitation treatment but it cannot be used in the quantification of the soil loss after the application of the erosion control measures. The comparisons between the results of the three cases indicate the importance of the immediate erosion control measures in order to mitigate soil loss and restore the natural environment.