Mercury pollution in the Chongqing part of the Three Gorges Reservoir area and its remediation and prevention

Mercury pollution in the Three Gorges Reservoir area of P. R. China merits special attention. We investigated into the current situation in the Chongqing part of the Reservoir area, identified the pollution sources and proposed some suggestions for the remediation and prevention of mercury pollution in this area. Atmospheric mercury in Chongqing was mainly from coal burning and releases of mercury-containing products such as various types of lights and fever thermometers. Urban drainage in Chongqing and Changshou, and runoffs from the high mercury background area in the lower reaches of the Wujiang River contributed most of the mercury in the water of the Yangtze River. A majority of the blame should be laid on mercury and gold mining in the Wujiang valley. We suggested foresting sloping lands to relieve soil erosion and prevent mercury-bearing soil from running into rivers, educational activities to discourage use of mercury-containing products and improved infrastructure to collect mercury-containing wastes for reducing mercury releases, more facilities for treating wastewater and solid waste to accommodate increased requirements of discharge, and growing selected perennial plants in mercury-contaminated land to absorb the mercury in soil. We also suggested concerted operation of a dedicated water-quality monitoring system, reinforced legislation and an effective administrative mechanism to ensure lasting efforts are invested in curbing mercury releases and restoring mercury contaminated land and water in the Reservoir area.     

安徽地区粘性土的76g锥与100g锥液限的关系

根据安徽淮北地区高速公路沿线大量的取土坑的试验资料,利用归纳法推导提出安徽地区尤若是淮北地区76g瓦氏圆锥仪与100g锥液限的关系式。     

Screening of plane S waves by an array of rigid piles in poroelastic soil

An array of rigid piles used as a screening barrier for plane shear （S） waves is investigated in a homogeneous unbounded space. The dynamic poroelastic theory of Biot is employed, under the assumption of an incompressible solid grain. Using Fourier-Bessel series, the problem of multiple scattering is solved by imposing continuity conditions and equilibrium conditions at the soil-pile interfaces with the translational addition theorem. A parametric analysis is conducted to investigate the influence of the permeability of poroelastic soil, separation between piles, number of piles and frequency of incident waves on screening effectiveness of the barrier, and the results are compared with those in an elastic soil medium. Computed results show that the intrinsic permeability of the soil medium displays an apparent effect on the screening of plane S waves.     

不同土壤条件对曼地亚红豆杉抗寒性影响研究

以不同土壤(酸壤和碱壤)条件下3年生曼地亚红豆杉为材料,用生理生化方法从低温半致死温度(LT50)、自由水和束缚水含量2项生理指标研究了曼地亚红豆杉在自然降温过程中抗寒力的变化,所得各项结果分别为:(1)不同土壤条件的曼地亚红豆杉低温半致死温度在自然降温过程中均随着气温的降低而降低,且与采样前半月平均最低温度呈线性相关,在整个变化过程中,二者的低温半致死温度均表现为:酸性土壤小于碱性土壤.(2)酸性土壤条件下束缚水含量和束缚水与自由水比值均明显高于碱性土壤条件下.最后确定了曼地亚红豆杉抗寒性大小为:酸性土壤强于碱性土壤.     

大兴安岭不同演替阶段土壤呼吸及其组分的动态

土壤呼吸及其组分随森林演替的变化对于长期碳循环模型及其地下碳储量至关重要.为了研究土壤呼吸随森林演替的变化及其影响机制,在2019年大兴安岭地区选取草地(GL)、白桦林(BF)、白桦与落叶松混交林(MF)、落叶松林(LF)4个不同演替阶段并对其进行研究.采用壕沟法测定自养(RA)和异养(RH)呼吸.结果 表明,GL、BF、MF和LF的土壤呼吸(RS)分别为3.11,5.68,5.54和4.69 μmol·m-2·s-1,RH分别为2.37,4.56,4.31和3.50 μmol·m-2·s-1,RA分别为0.74,1.12,1.23和1.19 μmol·m-2·s-1,GL、BF、MF、LF去除凋落物后Rs值分别为3.01,5.21,5.24和2.88 μmol·m-2·s-1.GL、BF、MF和LF中RA对Rs的贡献分别为23.79％,19.72％,22.20％和25.37％.演替阶段对Rs有显着影响(P＜0.05).回归分析发现,RA与细根生物量呈正相关(P＜0.01),RH与森林凋落物质量呈显著正相关(P＜0.05).试验的结果强调了演替阶段对土壤呼吸不同成分的重要性及其对估算森林碳汇潜力的重要性.     

盐渍土水分下渗能力及水盐动态运移试验

为探究盐渍化土壤水分下渗规律、水分下渗能力及水盐动态运移过程,设计了土壤剖面分层定水头供水及土壤剖面变水头供水下渗实验。测定不同层位土壤水分下渗率、含水率、孔隙水溶液电导率及土壤体电导率等参数,进行入渗条件下水盐动态运移规律分析。试验结果表明:盐渍化土水分下渗规律可由积水入渗Kostiakov模型进行刻画;浅层0~40 cm土壤相对于深层40~60 cm土壤具有较强的拦截和贮存入渗水分能力;盐渍化土壤盐分变动带位于浅层0~40 cm,且20~40 cm深度的土壤盐分波动幅度较大,深层40~60 cm土壤孔隙水溶液盐分向下运移的通量与土壤体盐分对其的补充量达到动态平衡,水分下渗过程中深层土壤孔隙水盐分含量相对平稳。实验结果为盐渍土的防治提供参考。     

锰矿冶炼中Fe、Mn对周边土壤的影响

通过对某锰矿冶炼厂周边地区土壤中铁锰元素的分析,发现冶炼厂周围土壤受锰矿冶炼厂的污染。含大量铁锰元素的粉尘、矿渣等进入土壤,使土壤中铁锰元素显著增加。实验结果显示:该冶炼厂附近土壤受Fe、Mn元素污染较重,土壤中铁锰含量分别为20250.78￣28426.06mg·kg-1、674.41￣4467.66mg·kg-1,已超出正常范围。冶炼厂粉尘中铁锰含量分别为78425.51￣78800.34mg·kg-1、100052.02￣100286.13mg·kg-1,矿渣中铁锰含量分别为2955.35￣3076.58mg·kg-1、7901.24￣8012.12mg·kg-1。土壤中铁锰含量与粉尘、矿渣中铁锰含量具有一定的相关性。该冶炼厂周围土壤已受到一定程度的污染。     

有机物料施用量对土壤CO_2排放速率的影响

本试验选用有机碳含量不同的黑土,研究了有机物料施用量对土壤CO2排放速率的影响.研究表明,施用有机物料以后CO2排放速率明显增加,5%和3%处理CO2排放速率增加幅度显著高于2%和1%处理.有机碳分解初期CO2排放速率增加较快,波动性大,后期趋于稳定,其相对值大小随有机物料施用量及土壤有机碳含量增加而增加,即6号土>5号土>4号土>1号土.3号土性质与其它土壤样品略有不同,CO2排放速率偏高.     

干旱胁迫对不同玉米品种叶片膜透性的影响

对不同玉米品种进行干旱处理,对叶片含水量、土壤含水量、叶片质膜透性进行测定．结果表明,土壤干旱胁迫条件下,玉米叶片含水量下降,叶片质膜透性上升;随着胁迫时间的延长,即土壤含水量的降低,叶片质膜透性不断的增加,其中新实1号的变化幅度最小,而叶片含水量则随之不断的减少,与叶片质膜透性的结果相符．这说明幼苗期新实1号的抗旱能力较强．因此,对叶片含水量、土壤含水量、叶片质膜透性的测定可以作为幼苗期抗旱鉴定的重要指标．     

论原始彩陶的尚土意识及文化史观

人类的生存状态,包括经济生活方式,都关系着他们采取何种方式造物,以及这种造物的目的和加工制作方法。原始彩陶对泥土的发现和利用,同样体现了人类对自然材料感知、适应、选择的主体性调适的能量。人们从陶土所折射出的生命潜力和精神意蕴中,不仅清晰的感受到了人类生命结构中浓烈的尚土意识,还悄无声息地滋生着一种不可名状的恋土情结。