中国长江口潮滩湿地土壤重金属含量的时空变化规律及环境指示意义

The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chongming Island (EC) and the Jiuduansha Shoal (JS) of the estuary were selected as the study sites. At each of the two sites, a cross-transect from land to sea was established and topsoil and soil core samples in the cross-transect were collected spatially and seasonally to determine their contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Mn, and Fe) and grain-size characteristics. The results showed that the heavy metal loads were commonly higher in the soils of nearshore high tidal flats and had a tendency of decreasing from land to sea at both of the study sites. The contents of heavy metals in the soils of the high and medial tidal flats were mostly higher in April and November but lower in July. Corresponding spatial and seasonal variations in grain size of the intertidal soils were also observed at the two study sites. The soils in the nearshore high tidal flats were finer and gradually got coarser seawards; they were relatively finer in April and November but coarser in July. Furthermore, the contents of heavy metals in the intertidal soils of both the sites EC and JS were significantly positively correlated with the clay (<2 μm) and 2-20 μm fractions, but negatively with the sand (>63 μm) and 20-63 μm fractions, which suggested that the heavy metals in the intertidal soils were primarily combined with the fine particulate fraction (<20 μm), especially clay, and hence the spatial and seasonal variations in heavy metals were actually caused by the change of the grain-size characteristics of the intertidal soils due to the different sedimentary environments in the estuary. The results of this study may also contribute to a better understanding of the soil formation and classification in the tidal flats of the Yangtze Estuary.     

中国太原市农业土壤的重金属污染状况

To evaluate the current state of the environmental quality of agricultural soils in Taiyuan City, a hotspot for China’s industrial development, the concentrations of 8 heavy metals in soils were investigated by means of extensive sampling in farmlands, forestlands, and grasslands in the city. Statistical analyses and spatial distribution maps were used to identify the most significant heavy metal pollutants. The mean concentrations of As, Cd, Cu, Hg, Pb, Zn, Ni, and Cr were slightly higher than their background values in Taiyuan’s topsoil, but were lower than the maximum permissible concentrations in the Chinese Environmental Quality Standard for agricultural soils. Farmland soils in Taiyuan had the highest average Cd, Cu, Hg, Pb, Zn, and Cr concentrations, but the As and Ni concentrations did not differ significantly among the farmland, forestland, and grasslands. Soil contamination by Cd, Cu, Hg, Pb, Zn, and Cr was mainly derived from farming practices, especially the use of sewage water for irrigation. In contrast, As and Ni might derive mainly from the soil parent material. The identification of heavy metal sources in agricultural soils may provide a basis for taking appropriate action to protect soil quality.     

杭州市城市土壤中重金属、磷和其它元素的特征

Health implications of inhaling and/or ingesting dust particles with high concentrations of heavy metals from urban soils are a subject of intense concern. Understanding the geochemistry of these metals is key to their effective management. Total concentrations of heavy metals, phosphorus (P) and 8 other elements from topsoil samples collected at 82 locations in Hangzhou City were measured to: a) assess their distribution in urban environments; and b) understand their differentiation as related to land use. Metal mobility was also studied using a three-step sequential chemical fractionation procedure. About 8.5%, 1.2%, 3.6%, 11.0% and 30.3% of the soil samples had Cd, Cr, Cu, Pb, and Zn concentrations, respectively, above their allowable limits for public and private green areas and residential use. However, in commercial and industrial areas, most samples had metal concentrations below their allowable limits. Statistical analyses revealed that the 16 measured elements in urban soils could be divided into four groups based on natural or anthropic sources using a hierarchical cluster analysis. Additionally, Cu, Pb, and P showed similar spatial distributions with significant pollution in commercial zones, suggesting vehicle traffic or commercial activities as dominant pollutant sources. Also, Cd, Co, Cr, Ni, Zn, Mn and Fe had the highest concentrations in industrial locations, signifying that industrial activities were the main sources of these seven metals. Moreover, the data highlighted land-use as a major influence on heavy metal concentrations and forms found in topsoils with large proportions of soil Cd, Co, Cr, and Ni found in residual fractions and soil Cu, Pb and Zn mainly as extractable fractions.     

森林土壤重金属的分布和迁移: 一种高密度采样方法的应用

The vertical distribution and migration of Cu, Zn, Pb, and Cd in two forest soil profiles near an industrial emission source were investigated using a high resolution sampling method together with reference element Ti. One-meter soil profile was sectioned horizontally at 2 cm intervals in the first 40 cm, 5 cm intervals in the next 40 cm, and 10 cm intervals in the last 20 cm. The migration distance and rate of heavy metals in the soil profiles were calculated according to their relative concentrations in the profiles, as calibrated by the reference element Ti. The enrichment of heavy metals appeared in the uppermost layer of the forest soil, and the soil heavy metal concentrations decreased down the profile until reaching their background values. The calculated average migration rates of Cd, Cu, Pb, and Zn were 0.70, 0.33, 0.37, and 0.76 cm year^-1, respectively, which were comparable to other methods. A simulation model was proposed, which could well describe the distribution of Cu, Zn, Pb, and Cd in natural forest soils.     

陇海铁路郑州—圃田段铁路旁土壤重金属污染

The pollution status and horizontal distribution of heavy metals (Ni, Pb, Cr, Zn, Cu, and Cd) in the soil on railroad side along the Zhengzhou-Putian section of Longxi-Haizhou Railroad were studied by collecting soil samples along a sampling section perpendicular to the railroad at the distances of 0, 10, 20, 30, 50, 100, 200, 300, and 500 m from the railroad edge. The concentrations of heavy metals in the sampling soils were higher than those of the control site. The concentrations of Pb, Zn, and Cd were found to be the highest in the soils at the railroad edge, and then decreased with increasing distance from the railroad. The highest concentrations of Ni, Cr, and Cu in soils were located at about 10-30 m from the railroad. Compared with the single factor pollution index (SFPI) of heavy metals calculated for the control site, the average SFPI from the sampling sites decreased in the order of Cr > Cd > Pb > Zn > Ni > Cu. There were notable negative correlations between the integral pollution index (IPI) of soil heavy metals at all sampling sites and the distances from the railroad. According to three IPIs calculated from the background values of heavy metals in och-aquic Cambisols, the heavy metal concentrations in the control soil, and the 2nd levels for soil heavy metals in GB15618-1995, the study area could be divided, based on the distances from the railroad, into four pollution zones: heavy pollution zone (0-10 m), medium pollution zone (10-50 m), slight pollution zone (50-100 m), and warning zone (100-500 m), respectively.     

尾矿池里添加大理石废料和有机物五年后植被覆盖和土壤生化特性研究

Tailing ponds pose environmental hazards,such as toxic metals which can contaminate the surroundings through wind and water erosions and leaching.Various chemical and biochemical properties,together with extractable and soluble metals were measured five years after reclamation of a polluted soil affected by former mining activities.This abandoned mine site contains large amounts of Fe-oxyhydroxides,sulphates,and heavy metals.As a consequence,soils remain bare and the soil organic matter content is low(< 3 g kg 1).Marble waste,pig manure and sewage sludge were applied in 2004.Plant cover and richness,and soil chemical,biochemical and biological parameters were analysed five years later.Results showed that all soil biochemical properties as well as vegetation cover and richness were higher in treated soils than in the untreated contaminated plots(control),although organic matter,pH values and extractable metals concentrations were similar among treatments.Soluble cadmium and zinc were lower in the amended plots than in control.As a general pattern,soil amended with pig manure showed higher values of most biochemical properties compared to sewage sludge application,while the doses did not have a great effect,being only significant for β-glucosidase,phosphodiesterase and arylsulfatase.Significant correlations were found between vegetation cover,richness and soil biochemical properties,suggesting a high interdependence between plant colonization and reactivation of biogeochemical cycles during five years.This study confirms the high effectiveness of an initial application of the amendments tested to initialize the recovery of ecosystems in bare mine soils under Mediterranean semiarid conditions.This research also shows the high sensitivity of certain biochemical properties in order to evaluate soil quality and reactivation of nutrients cycles in reclaimed mine soils.     

Heavy Metals, Phosphorus and Some Other Elements in UrbanSoils of Hangzhou City, China

Health implications of inhaling and/or ingesting dust particles with high concentrations of heavy metals from urbansoils are a subject of intense concern. Understanding the geochemistry of these metals is key to their effective management. Total concentrations of heavy metals, phosphorus (P) and 8 other elements from topsoil samples collected at 82locations in Hangzhou City were measured to:a) assess their distribution in urban environments;and b) understand theirdifferentiation as related to land use. Metal mobility was also studied using a three-step sequential chemical fractionationprocedure. About 8.5%, 1.2%, 3.6%, 11.0% and 30.3% of the soil samples had Cd, Cr, Cu, Pb, and Zn concentrations,respectively, above their allowable limits for public and private green areas and residential use. However, in commercialand industrial areas, most samples had metal concentrations below their allowable limits. Statistical analyses revealedthat the 16 measured elements in urban soils could be divided into four groups based on natural or anthropic sourcesusing a hierarchical cluster analysis. Additionally, Cu, Pb, and P showed similar spatial distributions with significantpollution in commercial zones, suggesting vehicle traffic or commercial activities as dominant pollutant sources. Also, Cd,Co, Cr, Ni, Zn, Mn and Fe had the highest concentrations in industrial locations, signifying that industrial activities werethe main sources of these seven metals. Moreover, the data highlighted land-use as a major influence on heavy metalconcentrations and forms found in topsoils with large proportions of soil Cd, Co, Cr, and Ni found in residual fractionsand soil Cu, Pb and Zn mainly as extractable fractions.     

伊朗中部伊斯法罕地区土地利用对石灰性土壤磁性质和重金属的空间分布的影响

Anthropogenic activities have caused the accumulation of heavy metals in the soil environment. Pollution of the soils significantly reduces environmental quality and affects human health. In many recent studies, magnetic susceptibility measurements have been used for pollution monitoring. The objective of this research was to determine the spatial variability of magnetic properties and selected heavy metals and the effects of land use on their variability in the surface soils of the Isfahan region, Central Iran. A total of 158 composite surface (0-5 cm) samples of calcareous soils were collected from an area of about 700 km2, located along a cross-border transect from Isfahan City to a steel plant, covering urban, industrial, agricultural and uncultivated land uses. Concentrations of copper (Cu), zinc (Zn), lead (Pb), manganese (Mn), iron (Fe), nickel (Ni), chromium (Cr), and cobalt (Co) and magnetic parameters, magnetic susceptibility at low frequency (χlf), natural remanent magnetization (NRM), saturation isothermal remanent magnetization (SIRM), and isothermal remanent magnetization at the field of 100 mT (IRM100mT) and the backfield of 100 mT (IRM-100mT), were measured in all the soil samples. Results showed that magnetic susceptibility in the urban and industrial land topsoils (0--5 cm) samples was significantly higher than that in the agricultural and uncultivated land soils in the study area. Concentrations of Cu, Zn, Pb, Mn, and Fe were positively correlated with magnetic properties (χlf, IRM100mT, SIRM, IRM-100mT, and NRM), which could be attributed to their inputs from traffic emissions and industrial activities at the study sites. Ni and Cr concentrations showed significant negative correlations with magnetic properties. No significant correlation was found between Co concentration and magnetic parameters. The Tomlinson pollution load index (PLI) showed significant correlation with the magnetic properties (χlf, IRM100mT, SIRM, IRM-100mT, and NRM). The spatial distribution of the selected heavy metals and χlf in the study area suggested that activities at the urban and industrial land sites caused greater pollution as compared to that at the study sites of other land uses. The concentrations of Cu and Zn seemed to have been affected by anthropogenic sources, whereas Ni, Cr, and Co were mainly controlled by natural sources in the study area. Moreover, the concentrations of soil Pb and Fe in the study area could be affected by both lithologic and anthropogenic sources. The magnetic parameters appeared to be a proxy measure for the degree of heavy metal contamination and could be a potential method for the detection and mapping of contaminated soils.     

红壤重金属的复合污染

The effects of combined heavy metal pollution of red soil on the growth of wetland rice and the transfer of Pb,Cd,Cu and Zn from soil into plants were sudied by greenhouse pot experiment,The results showed that the plantyields were markedly affected by heavy metals,with the exception of Pb,in soils under the experimental conditions,without taking into consideration all the interactions among the elements.The concentrations of the elemets in plants were mainly affected by the specific element added to the soil.The effect of interactions among the heavy metals was very significant either on plant yields or on the concentration of the elements in plants.The risk assessment of a combined pollution by heavy metals in the soil is discussed preliminarily in terms of the relative pollution equivalent.     

肥料投入与平衡土壤养分及产出效应研究

通过地力调查及土壤、施肥情况动态监测 ,找出制约农业生产发展的土壤养分限制因子 ,依据土壤养分、肥料变化状况及作物产出效应 ,分阶段提出培肥改土的施肥方针和技术措施 ,进行试验示范。根据试验示范结果 ,得出不同时期、不同作物的土地生产力和氮、磷肥利用率 ,使肥料结构逐步趋于合理 ,充分发挥肥料的产出效应     

基于LUCC的渭干河—库车河三角洲绿洲水文及生态特征

高强度的人类活动促使LUCC对水圈和生物圈产生了巨大的影响,以塔里木盆地北缘典型绿洲渭干河—库车河三角洲绿洲为研究区,采用1989年、1998年以及2013年多期遥感影像,利用最大似然的方法对影像进行分类并统计出研究区耕地、林地、盐渍地、水体以及裸地的变化,讨论LUCC对水文及生态特征的影响。结果表明:(1)从水文特征方面来看,由于人类活动强度加强导致渭干河—库车河三角洲绿洲的LUCC大幅度的改变。自1989—2013年这25a间,耕地面积总共增加2.408×103km2。而由于耕地面积的增加,促使用于灌溉等用水量大量增加,加上修建渠道、水库等活动促进地表径流量有所增加,导致研究区年径流量呈现出缓缓上升趋势。因为随着灌区排水系统的完善,疏干了低洼地的积水,降低了相应地域的地下水位,从而造成地下水位呈现出逐年下降的趋势。(2)从生态特征方面看,人类活动作为主导因素所导致的LUCC通过与气候变化交互作用,引起温度、湿度以及蒸发量发生变化;耕地面积的大范围增加,导致草地、林地等自然栖息地破碎化和丧失,加之25a间由于人为饲养家禽种类的简化、数量的大幅度增长,在综合作用结果下,最终导致生物多样性简化、单一性愈发显著。因此,本研究为系统开展LUCC对生态环境影响的趋势和机制方面有较高的科学价值。     

贵阳市蔬菜上市量与气象灾害关系的研究

统计,分析了贵阳市蔬菜气象灾害的成因,种类,特征及其对蔬菜生产影响的程度,结合蔬菜受害机制,再生力,影响程度,对蔬菜气象灾害进行分类,分级。初步认为暴雨,冰雹,连阴雨,,连续高温高湿,春旱,倒春寒６种气象灾害是贵阳市蔬菜生产的主要气象灾害,其中后４种气象灾害应作为防灾减灾的重点,提出蔬菜均衡上市的防灾减灾对策措施。     

开发建设中扰动地面新增水土流失研究

针对神府东胜煤田开采过程中所引发的严重新增水土流失问题,采用野外放水冲刷的试验研究方法,对神府东胜煤田扰动地面新增水土流失机理和流失量进行了初步研究。结果表明:在相同放水冲刷流量和坡度下,原始地面的平均土壤入渗率较扰动地面的增加30%;两种不同类型下垫面的径流量均随时间的增加而增加,冲刷的前6min,径流量均较小,且原始地面>扰动地面,在6min以后,径流量迅速增大,且原始地面<扰动地面,扰动地面的平均径流量较原始地面增加14%;原始地面的侵蚀产沙在整个放水冲刷过程中没有显著变化,基本维持在一个常数水平;扰动地面在放水冲刷0—15min的侵蚀产沙量较高,此后侵蚀产沙随冲刷历时的延长而下降并最终趋于稳定;扰动地面的平均含沙量较原始地面增加96%,平均产沙量增加89%;新增土壤流失量随放水流量和坡度的增大而增大,10°时,新增土壤流失量最大;同一坡度条件下,放水流量越小,土壤流失量增加的百分比就越大,反之则越小。     

基于GIS和RS技术水土流失规划研究——以浐灞河流域为例

以西安市浐灞河流域水土保持规划为例,利用GIS和RS技术对规划区域的生态适宜度进行了综合分析,并对不同水土保持规划方案可能的环境影响进行比较分析,旨在为复杂地形区的水土保持规划和建设提供科学的决策依据.把流域内新增的水土流失降低到最低程度.     

Mobility and breakdown of asulam in the soil and the possible impact on the environment

Asulam reaching the soil either directly as spray drift or as rain washings from bracken fronds would, due to its rapid mobility in soil, be expected to leach down the soil profile into the drainage water and thereby contaminate streams and water catchments. The mobility of asulam in soil is influenced by pH, where undissociated asulam will leach less rapidly than the associated form (asulam pK_a 4·82). This is particularly relevant in the case of bracken as it can grow satisfactorily over a wide range of pH values (3·6 – 7·6). Adsorption coefficients expressed as Kd values [(μg asulam/g soil)/(μg asulam/ml solution)] were 2·54, 1·94 and 0·96 at pH readings of 4·0, 4·3 and 4·9 respectively. Another factor involved, the breakdown of asulam, was shown to be temperature dependent, 30·95, 7·65 and 2·50% remaining after 28 days at 5, 18 and 25°C respectively, thus underlining the influence of geographical regions and climatic conditions on asulam behaviour.     

基于 Modis 数据的滇中地区2008年地表热环境及变化特征研究

以 MODIS 数据资料研究滇中地区地表温度动态变化规律,旨在为研究滇中地区地表热环境的影响积累资料,为自然资源监测、保护及其相关领域提供理论数据,为相关部门制定决策提供科学依据.在总结和分析当前常用地表温度反演算法的基础上,采用分裂窗算法来反演地表温度.分析了2008年滇中地区地表热环境的变化特征,结果表明:在热量分布方面,由西北向东南递增,东部丰富、西部偏少.     

大同市水土保持综合治理研究及展望

大同市属水蚀、风蚀交错区,全市总土地面积14 107km^2,水土流失面积9793km^2,年土壤侵蚀模数达4 000t/km^2～5 000t/km^2,是全省水土流失严重的区域之一.文章论述了水土保持治理与研究情况,提出了新世纪应注意解决好的几个问题.     

气候与下垫面变化对黄土高原蒸散发变化的影响评估

为了揭示近20年黄土高原蒸散发(evapotranspiration,ET)时空变化规律,明晰气候和下垫面变化对蒸散发的影响作用。基于黄土高原295个气象站数据、PML_V2 ET产品及MOD13A1 EVI产品,采用趋势分析和多元回归分析等统计方法,分析了2000—2018年黄土高原蒸散发时空变化特征,并评估了降雨、温度、日照时间、饱和水汽压差、植被和非植被下垫面等影响要素的相对贡献率。结果表明:(1)2000—2018年黄土高原蒸散发年际变化率为4.47 mm/a,62.8%的区域蒸散发呈显著增加趋势,主要分布在山西、青海、陕西省北部地区;不同土地覆盖ET为森林＞农田＞草地＞灌木。(2)植被显著增加是黄土高原ET变化的主导因子,其相对贡献率最大(32.1%);不同气象要素对黄土高原ET相对贡献率大小为降雨(14.6%)＞饱和水汽压差(13.2%)＞温度(12.4%)＞日照时数(10.0%);非植被下垫面变化(水土保持工程措施等)对ET变化的影响作用不容忽视。(3)气象要素和增强型植被指数(enhanced vegetation index,EVI)对林草覆被ET影响作用＞农田覆被ET,而非植被下垫面要素对农田覆被ET的影响作用较大。研究结果为黄土高原生态建设、水资源消耗恢复和水资源可持续性评价提供科学支撑。     

哺乳动物第一和第二极体的研究

卵母细胞在减数分裂过程中相继排出第一和第二极体,这些极体内的染色体和留细胞内的染色体同样具有遗传和生殖潜力,可用作生产有生殖能力的后代。因此,从理论上讲用一个卵母细胞的染色体可能繁殖出４个子代。