压力板仪法测土-水特征曲线试验研究

非饱和土土-水特征曲线(SWCC)表示了土中含水量与吸力之间的关系。针对非饱和土干-湿循环过程中的吸力变化特征,开展试验研究。采用体积压力板仪实现非饱和土的脱湿和吸湿过程。试验成果显示:(1)土-水特征曲线是不稳定的,它与土体含水率的变化路径有关;(2)在干湿循环过程中,相同的基质吸力具有不同的含水量。     

土壤中4-溴苯胺降解动力学及其生态毒性追踪

秀谷隆是一种被广泛应用的取代脲类除草剂,其主要降解产物为４－溴苯胺（４－ＢＡ）,研究４－溴苯胺在不同土壤中的降解动力学规律,并用土壤环境指示动物弹尾目跳虫Ｃｏｌｌｅｍｂｏｌａ（Ｆｏｌｓｏｍｉａ ｃａｎｄｉｄａ）跟踪指示该化合物在进一步降解过程中的毒性,结果表明：４－溴苯胺在土壤中的降解行为可用一级反应动力学方程来较好地描述,其生态毒性明显高于母体化合物秀谷隆,该化合物在粘土中的残留量低于砂土,但毒     

Bison and cattle grazing management,bare ground coverage,and links to suspended sediment concentrations in grassland streams

This study quantified the impact of bison and cattle grazing management practices on bare ground coverage at the watershed, riparian, and forested riparian scales within the Flint Hills ecoregion in Kansas. We tested for correlations between bare ground coverage and fluvial suspended sediment concentrations during base‐flow and storm‐flow events. We used remotely sensed imagery combined with field surveys to classify ground cover and quantify the presence of bare ground. Base‐flow water samples were collected bi‐monthly during rain‐free periods and 24 h following precipitation events. Storm‐flow water samples were collected on the rising limb of the hydrograph, using single‐stage automatic samplers. Ungrazed treatments contained the lowest coverage of bare ground at the watershed, riparian, and forested riparian scales. Bison treatments contained the highest coverage of bare ground at the watershed scale, while high‐density cattle treatments contained the highest coverage of bare ground at the riparian and forested riparian scales. In bison and cattle‐grazed treatments, a majority of bare ground was located near fence lines, watershed boundaries, and third‐ and fourth‐order stream segments. Inorganic sediment concentrations at base flow were best predicted by riparian bare ground coverage, while storm‐flow sediment concentrations were best predicted by watershed scale bare ground coverage.     

北京地区土壤对柴油的吸附及影响因素研究

通过静态吸附实验,研究了北京地区土壤对柴油的吸附行为,考察了溶液pH和添加乙醇对柴油吸附的影响. 结果表明,6种不同土样对柴油的吸附等温线均较好地符合Langmuir吸附方程,其吸附系数(K)分别为0.193, 0.218, 0.203, 0.199, 0.211和0.182 L/mg,6种土样吸附能力依次为轻壤土>轻粘土>中壤土>砂壤土>重壤土>紧砂土,这主要是由于6种土样的pH,有机质含量和机械组成不同所致;溶液pH的升高,不利于柴油在土壤中的吸附,pH从4升高到10,柴油在1～6号土样中的吸附量分别从1　012, 1　800, 1　377, 1　272, 1　601和862 μg/g降低到114, 236, 163, 150, 201和85 μg/g;向柴油中添加乙醇会减小柴油的吸附量,并且吸附量随添加乙醇量的增大而降低,这有利于柴油的向下运移.      

我国典型土壤对病毒等温静态吸附的数值模拟

通过室内等温静态批量平衡吸附实验,采用3种常见的等温线（Freundlich方程、Langmuir方程和Temkin方程）对2种病毒（MS2和X174）在2种处理（非灭菌和灭菌）条件下的6种土壤（红壤土、红粘土、乌栅土、黄泥土、沙质潮土和壤质潮土）中的吸附行为进行了回归拟合.实验结果和模拟结果均表明,土壤性质、病毒性质、土壤中的土著微生物对病毒在土壤中吸附行为均具有重要的影响.红粘土对MS2和X174的平均吸附比例几乎能达到100％,而2种潮土（沙质潮土和壤质潮土）相对较弱;总体来看土壤对X174的吸附能力高于MS2,但灭菌后的土壤对MS2的吸附能力却高于X174.在数值模拟中,Freundlich方程和Langmuir方程均具有理想的相关性.Freundlich方程能够表现出病毒浓度对其在土壤中吸附行为的影响;尽管Langmuir方程能够应用于土壤对病毒吸附能力的比较,但本研究中不能应用Langmuir方程来计算土壤对病毒的最大吸附量.     

荧光分光光度法测定土壤中石油类

建立了荧光分光光度法测定土壤中石油类.方法检出限为3 mg/kg,实际土壤加标回收率为95.5％ ～108％,精密度(RSD,n=6)为2.4％ ～8.7％.实验结果表明,该方法准确可靠、灵敏度高、选择性好、操作简便,与红外分光光度法有较好的可比性,满足土壤中石油类分析要求.     

铁、铝氧化物和土壤对苄嘧磺隆的吸附

用平衡吸附法研究了苄嘧磺隆在两种土壤(广州赤红壤、湖南红壤)和两种人工合成氧化物(针铁矿、铝氧化物)中的吸附,以及pH对吸附的影响.结果表明:(1)用Langmuir,Freundlich和Temkin等温方程描述供试样品对苄嘧磺隆的吸附,其中Freundlich吸附等温方程拟合的结果较佳.在苄嘧磺隆的实验浓度范围内和一定的pH条件下,吸附苄嘧磺隆的量随其浓度的升高而增加,其顺序为:铝氧化物＞湖南红壤＞针铁矿＞广州赤红壤.(2)苄嘧磺隆在供试样品中的吸附量随溶液pH值的升高而减小.     

贵州汞矿矿区不同位置土壤中总汞和甲基汞污染特征的研究

为了深入理解汞矿矿区土壤中总汞和甲基汞的污染特征,应用AAS、GC-CVAFS方法,分别对贵州万山、务川和滥木厂汞矿矿区不同位置土壤以及对照区土壤中的总汞(THg)和甲基汞(MeHg)进行了测定.结果表明,万山汞矿区土壤THg和MeHg含量范围分别为1.1～790 mg·kg^-1和0.19～15μg·kg^-1,务川汞矿区土壤THg和MeHg含量范围分别为0.33～317mg·kg^-1和0.41～20μg·kg^-1,滥木厂汞矿区土壤THg和MeHg含量范围分别为0.41～610 mg·kg^-1和0.70～8.8μg·kg^-1.对照区土壤汞含量明显低于矿区土壤,其THg和MeHg含量范围分别为0.14～1.2 mg·kg^-1和0.09～0.23μg·kg^-1;对照区土壤THg含量接近或稍高于全球背景土壤THg含量0.01～0.5 mg·kg^-1.研究表明,汞矿区稻田土壤具有较强的汞甲基化能力,其MeHg含量明显高于菜地和旱田土壤;万山汞矿区土壤汞污染程度明显高于滥木厂和务川汞矿区土壤汞污染.     

Method optimization to measure polybrominated diphenyl ether (PBDE) concentrations in soils of Bratislava, Slovakia

We modified an analytical method to determine polybrominated diphenyl ethers (PBDEs) in urban soils of Bratislava (Slovakia). Gel permeation chromatography (GPC) introduced as a clean-up step for soil extracts substantially reduced matrix enhancements when PBDEs were measured with gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The resulting method proved to be accurate, precise, and showed low detection limits. The sum of 15 PBDE concentrations in surface horizons of Bratislava soils ranged from 87 to 627 pg g⁻¹. PBDE concentrations were mostly higher in surface than deeper horizons probably because of atmospheric deposition and lack of substantial vertical transport. Lower brominated PBDEs undergo more soil-atmosphere exchanges or are more scavenged and transferred with litter fall to the soil organic matter than higher brominated ones as suggested by the correlation between lower brominated PBDEs and soil organic C (C_org) concentrations.     

Inventory and vertical migration of 90Sr fallout and 137Cs/90Sr ratio in Spanish mainland soils

In this paper the inventory of ⁹⁰Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m² and 2047 Bq/m². From these data set and those ¹³⁷Cs data obtained in a previous work the ¹³⁷Cs/⁹⁰Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for ¹³⁷Cs an average value 57% lower than that obtained for ⁹⁰Sr.Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective-diffusive model, the parameters of the model which governs the vertical migration of ⁹⁰Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm²/year, respectively.