高原湿地剑湖湖滨带功能作用的定量研究

采用野外采样与室内分析的方法，从水质和底泥两个方面定量研究剑湖湖滨带的功能作用。结果表明，湖滨带在水质净化和拦截泥沙等方面效果显著，特别是对水中总氮与总磷的平均去除率分别高达66．28％和45．73％，其拦截作用表现为：迎水面的泥层厚度是背水面的1．5倍；底泥的各项指标（除pH值），湖滨带背水面均比迎水面高，速效磷和全氮的增加量最为明显，其含量分别是迎水面的3．30和2．61倍，这主要与湖滨植物带大量吸收入湖矿质营养用于自身生长，其残体在背水面沉积有关，从另一角度体现了湖滨带的吸附、净化功能。因此，要重视并保护湖滨带，从而使其功能得到有效发挥。     

攀枝花地区河流沉积物的重金属污染研究

攀枝花市是长江流域经济带上游区第一城，几十年的开发建设使该地区的经济、社会得到了飞速的发展，但同时也造成了一定的环境影响。采用地质累积指数评价了该区水系沉积物中的重金属污染状况，结果表明，水系沉积物中各元素的污染程度由高到低为：Ti、Cu、V、Pb、Zn、Cr、As；总体上看，各元素在攀钢采矿场、选矿厂、冶炼厂及尾矿坝等地的污染程度较高，表明该区水系沉积物中重金属和攀枝花地区金沙江水质的污染主要与该区钒钛磁铁矿的采、选、冶等矿业活动有关。该区应采取如下措施减轻环境影响：(1)加强矿区环境恢复和环境管理，确保区域资源、环境、经济、社会可持续发展；(2)加强城市环境监测，特别是重金属和其他微量元素污染的监测，进行城市生态环境安全预警。     

GRAZED STUBBLE HEIGHT AS A CRITERION FOR CONTROLLING SEDIMENT PRODUCTION FROM GRAZING LANDS1

ABSTRACT: Efforts by state and federal agencies to develop standards and guidelines for protecting and enhancing water quality on grazing lands have led to suggestions that grazed stubble height criteria could be used to determine when cattle should be removed from a specific pasture or grazing area. Until recently only indirect scientific evidence from agronomy and laboratory studies gave support to the stubble height concept. Consequently, a grazing study was initiated on a Montana ranch in 1997 to determine the reduction in overland sediment achieved by grazing a pasture to a predetermined stubble height. Treatments consisted of 7 cm (3 in) grazed, 7 cm (3 in) clipped or mowed, 15 cm (6 in) grazed; 15 cm (6 in) clipped and untreated or natural forage plant height. The five treatments were used in a two‐year trial spanning 1997 to 1999. At the conclusion of this study the magnitude of sediment production was related to the number of intense rain events during the March through June period rather than total precipitation. There was a significant year effect in terms of sediment accumulation (P < 0.01) but no year by treatment effect (P = 0.11). Even though a significant difference in sediment accumulation was detected between the shorter and taller stubble heights (P = 0.04) in both 1998 and 1999, the difference could not be explained by grazed stubble height alone. Close grazing (7 cm stubble) consistently ranked lowest in sediment production (P < 0.01) among all treatments, including the ungrazed control. These results suggest that changes in plant community structure and microtopographic caused by grazing influence sediment entrapment (retention) on hillslopes more than those caused by plant height.     

Changes in Extractable Metal Concentrations During Storage of Surface Water Samples Containing Sediments1

ABSTRACT: Changes in metal concentrations during storage of acidified water samples were studied. Water samples with high concentrations of suspended sediment were collected from the Fraser River, British Columbia. These samples were analyzed for “extractable” metals, which are defined to be the dissolved metals plus those metals extracted from suspended sediment by dilute mineral acid. Concentrations of extractable Cu, Fe, Pb, Zn, Ni, Co, Mn, and Cd were determined over time. Metal concentrations in these water samples were not stable and showed significant increases throughout the storage period. These results suggest that the extractable metal technique is inappropriate for the analysis of water samples containing suspended sediment.     

沉积物和生物样品铜,铅测定的质量控制

通过测定方法选择，基础实验，空白值测定，精密和准确度控制有效地控制测定过程，保证测定数据准确，可靠，可比。     

DISCHARGE AND SUSPENDED SEDIMENT PATTERNS OF AN INTERMITTENT COLD DESERT STREAM1

Sage Creek in south‐central Wyoming is listed as impaired by the U.S. Environmental Protection Agency (USEPA) due to its sediment contribution to the North Platte River. Despite the magnitude of sediment impacts on streams, little research has been conducted to characterize patterns of sediment transport or to model suspended sediment concentration in many arid western U.S. streams. This study examined the relationship between stream discharge and suspended sediment concentration near the Sage Creek and North Platte River confluence from 1998 through 2003. The objectives were to determine patterns of stream discharge and suspended sediment concentration, produce a sediment prediction model, and compare sediment concentrations for the six‐year period. Stream discharge and suspended sediment transport responded rapidly to convective storms and spring runoff events. During the study period, events exceeding 0.23 m³/s accounted for 92 percent of the sediment load, which is believed to originate from erodible headwater uplands. Further analysis of these data indicates that time series modeling is superior to simple linear regression in predicting sediment concentration. Significant increases in suspended sediment concentration occurred in all years except 2003. This analysis suggests that a six‐year monitoring record was insufficient to factor out impacts from climate, geology, and historical sediment storage.     

Transformation of Particle-Bound Phosphorus at the Land–Sea Interface in a Danish Estuary

Danish rivers carry >50% of the phosphorus (P) transport as particulate P (PP). In five of six rivers sampled in November 1998 iron-bound P made up > 59% of PP and loosely adsorbed P ranged between 2% and 13%. This fraction could potentially be released in 14‰ seawater. The behaviour of dissolved and particulate P fractions was studied during seven month in a 2 km long estuary with low freshwater retention time and low tidal range. The river carried ∼10% of PP as loosely adsorbed P but increased concentrations of dissolved inorganic P (DIP) relative to the estuarine mixing line was only observed in the summer month with low freshwater flow and was more likely due to DIP release from the bottom sediment. Instead estuarine particles were always enriched with oxidized iron (ox.Fe) and iron-bound P as well as loosely adsorbed P and during May–September this coincided with increasing concentration of PP in estuary. We suggest that flocculation of ox.Fe and adsorption of DIP onto the particles with subsequent transport seawards is a major loss process for P during the summer month. During winter month where 85% of the run-off occurs the dominant process in the estuary is sedimentation of larger particles, however, a comparison of river particles with surface sediment clearly reveals that most PP is mobilized again from the bottom sediments.     

HYDROLOGIC EFFECTS OF CLEARCUTTING AND STRIPCUTTING LOBLOLLY PINE IN THE COASTAL PLAIN1

ABSTRACT: Harvesting 29-year-old loblolly pine (Pinus taeda L.) plantations on six small catchments in the Coastal Plain of west Tennessee caused variable but generally minor increases of storm-flow volumes during the four years following harvest. The increases were primarily associated with decreases of rainfall interception rather than with soil disturbance. Harvesting had no effect on stormflow volumes in six nearby catchments of 37-year-old loblolly pine to which the same treatments were applied. Postharvest increases of flow-weighted sediment concentrations averaged higher for the catchments with greater flows at both locations. During the fourth through eighth years after harvest, average sediment concentrations for harvested catchments at each location approximated closely the base rate of 62 mg L^-1 previously defined for undisturbed pine types. Thus, relatively minor postharvest increases of stormflow volumes in the six 29-year-old plantations and increases of sediment concentrations in all 12 catchments were limited to about four years. Nevertheless, because of potential channel erosion, the findings confirm the need to extend stream management zones well up into drainages with intermittent and ephemeral flows wherever water quality is a concern. Despite certain undesirable effects of logging (baring of mineral soil, decreased weight and depth of forest floor, increased soil bulk density), the results demonstrate the high resilience developed by pine planted on severely eroded sites in the southern Coastal Plain.     

苏北海域表层沉积物中PH_3的分布

为研究海洋生态系统中PH3的迁移转化规律及其产生机制,2006年12月对苏北海域表层沉积物中磷化氢(PH3)、总磷(TP)、无机磷(IP)、有机磷(OP)及有机质(OM)的分布进行了系统分析和讨论。结果表明,PH3在苏北海域表层沉积物中普遍存在,含量在[(2.63±0.38)~(39.35±5.49)]×10-12之间,最大值出现在长江口,最小值出现在辐射沙洲海域。辐射沙洲海域TP和IP的含量较低,长江口及吕四一带含量相对较高,且沿着长江入海方向逐渐减少。OP和OM分布的总体趋势是由南至北,由西到东含量逐渐减小,长江口及吕四港一带含量较高。区与区间PH3与TP、IP及OP的相关性分析表明,IP作为PH3的生成前体物可能性比OP高。     

辽宁省境内老哈河流域产沙特征及泥沙供给模式研究

在对辽宁省境内老哈河流域土壤侵蚀研究的基础上,通过计算泥沙迁移时间确定了该流域基于栅格尺度的泥沙输移比的空间分布,最终获得该流域的产沙量,结果表明北部的老官地、哈拉道口、烧锅营子等地以及中南部河流两侧是流域内主要产沙源;选用坡度、植被盖度、土地利用类型、土壤可蚀性、距河流距离、基岩岩性等因子,建立了老哈河流域泥沙供给的数学模型,结果表明流域产沙主要与坡度、距河流距离、土地利用类型和植被盖度密切相关。因此,改变土地利用类型、提高植被盖度是防治流域致灾泥沙的关键因素。本研究对今后老哈河流域土地利用规划及泥沙治理具有一定的指导意义。