酸/碱改性香蒲生物炭对水中磷的去除及其机制研究

雨水径流中存在的磷污染问题严重威胁生态环境,而传统的雨水径流处理设施,如雨水花园、渗滤沟等,对磷的去除率较低且成本较高.以湿地中收割的香蒲为原材料,酸改性后制备的生物炭（TH7）的除磷效果非常好,明显优于碱改性生物炭（TOH7）：与原生物炭（T7）相比,酸改性生物炭大大提高了磷的去除效率,可从T7的65%提高至94%,而碱改性生物炭无除磷效果.TH7的表面孔隙发达,比表面积高达434.2m²·g^-1,对磷的吸附符合Freundlich模型和伪二级动力学模型,其吸附属于物理化学吸附,具体的机制为孔隙填充、表面化学沉淀、氢键结合.研究表明,以香蒲为原料制备的改性生物炭是一种效果优越的除磷吸附剂,可应用于植草沟、雨水花园等以填料为主要吸附层的径流处理设施中.     

皖南丘陵地区小流域氮素径流输出的动态变化

以亚热带北部皖南丘陵地区小流域定位实地观测为基础 ,研究了农林共存小流域氮素径流输出规律。发现小流域氮素径流输出季节性变化明显。降雨和施肥是影响这一变化的重要因子 ,模拟分析表明 ,它们与氮素输出之间具有很好的线性相关关系     

济南市南部山区降雨特性分析

通过对济南市南部山区50年降雨资料的分析,得出南部山区年降雨量为648mm,降雨季节性明显,降雨量主要集中在6-8月份的降雨特点;采用皮尔逊Ⅲ型曲线拟合了降雨频率曲线,分析了降雨量与频率之间的关系,得出年降雨量在1000mm以上的频率是2%,年降雨量在640mm以上的频率是50%。最后采用一维坡地径流模型对南部山区内的典型丘陵的产流量进行了模拟计算,模拟结果和实测值吻合较好。     

Modelling vegetation greenness responses to climate variability in a Mediterranean terrestrial ecosystem

Accurate knowledge of the quality and environmental impact of the highway runoff in Pear River Delta, South China is required to assess this important non-point pollution source. This paper presents the quality characterization and environmental impact assessment of rainfall runoff from highways in urban and rural area of Guangzhou, the largest city of Pear River Delta over 1 year’s investigation. Multiple regression and Pearson correlation analysis were used to determine influence of the rainfall characteristics on water quality and correlations among the constituents in highway runoff. The results and analysis indicates that the runoff water is nearly neutral with low biodegradability. Oil and grease (O&G), suspended solids (SS) and heavy metals are the dominant pollutants in contrast to the low level of nutrient constituents in runoff. Quality of highway runoff at rural site is better than that of at urban site for most constituents. Depth and antecedent dry period are the main rainfall factors influencing quality of highway runoff. The correlation patterns among constituents in highway runoff at urban site are consistent with their dominant phases in water. Strong correlations (r ≥ 0.80) are found among chemical oxygen demand (COD), total phosphorus, Cu and Zn as well as conductivity, nitrate nitrogen and total nitrogen. O&G, COD, SS and Pb in highway runoff at urban site substantially exceed their concentrations in receiving water of Pear River. The soil directly discharged by highway runoff at rural site has contaminated seriously by heavy metals in surface layer accompanying with pH conversion from original acidic to alkaline at present.     

Spectroscopic Distribution of Dissolved Organic Matter in a Dam Reservoir Impacted by Turbid Storm Runoff

Spectroscopic characteristics of dissolved organic matter (DOM) in a large dam reservoir were determined using ultraviolet absorbance and fluorescence spectroscopy to investigate spatial distribution of DOM composition after turbid storm runoff. Water samples were collected along a longitudinal axis of the reservoir at three to four depths after a severe storm runoff. Vertical profiles of turbidity data showed that a turbid water layer was located at a middle depth of the entire reservoir. The spectroscopic characteristics of DOM samples in the turbid water layer were similar to those of terrestrial DOM, as demonstrated by the higher specific UV absorbance (SUVA) and the lower fluorescence emission intensity ratio (F ₄₅₀/F ₅₀₀) compared to other surrounding DOM samples in the reservoir. Synchronous fluorescence spectroscopy revealed that higher content of humic-like DOM composition was contained in the turbid water. Fluorescence excitation–emission matrix (EEM) showed that lower content of protein-like aromatic amino acids was present in the turbid water DOM. The highest protein-like fluorescence was typically observed at a bottom layer of each sampling location. The bottom water DOM exhibited extremely high protein-like florescence near the dam site. The particular observation was attributed to the low water temperature and the isolation of the local bottom water due to the upper location of the withdrawal outlet near the dam. Our results suggest that the distribution of DOM composition in a dam reservoir is strongly influenced by the outflow operation, such as selective withdrawal, as well as terrestrial-origin DOM inputs from storm runoff.     

HYDROCLIMATIC VARIABILITY IN THE ROCKY MOUNTAINS1

ABSTRACT: The spatial and temporal variability of hydroclimatic elements were investigated in the central and northern Rocky Mountains (Colorado, Idaho, Montana, Utah, and Wyoming) during the 1951–1985 period. The three hydroclimatic elements studied were total water-year (October 1-September 30) streamflow (ST), winter (October 1-March 31) accumulated precipitation (PR), and April 1 snowpack (SN). An analysis of 14 virgin watersheds showed wide spatial djfferences in the temporal variability of SN, PR, and ST, and these were found to be caused largely by basin exposure to moist air flows. The more stable (low variability) basins were those exposed to prevailing northerly to westerly flow, while unstable (high variability) basins were exposed to occasional southwesterly to southeasterly moist flow. Snowpack was the better indicator of ST in 11 of the 14 watersheds, explaining 37 to 87 percent of the ST variance. Analysis of the spatial variability, based on all SN and PR data from across the study area, revealed 11 discrete climatic regions. Both SN and PR exhibited coherent regions of stable and unstable temporal variability. The average variability between stable and unstable regions differed by a factor of two, and the differences were best explained by the exposure of the mountain barrier to moist air flows.     

MINIMIZING THE IMPACT OF URBANIZATION ON LONG TERM RUNOFF1

Increasing concern about the problems caused by urban sprawl has encouraged development and implementation of smart growth approaches to land use management. One of the goals of smart growth is water resources protection, in particular minimizing the runoff impact of urbanization. To investigate the magnitude of the potential benefits of land use planning for water resources protection, possible runoff impacts of historical and projected urbanization were estimated for two watersheds in Indiana and Michigan using a long term hydrological impact analysis model. An optimization component allowed selection of land use change placements that minimize runoff increase. Optimizing land use change placement would have reduced runoff increase by as much as 4.9 percent from 1973 to 1997 in the Indiana study watershed. For nonsprawl and sprawl scenarios in the Michigan watershed for 1978 to 2040, optimizing land use change placement would have reduced runoff increase by 12.3 percent and 20.5 percent, respectively. The work presented here illustrates both an approach to assessing the magnitude of the impact of smart growth and the significant potential scale of smart growth in moderating runoff changes that result from urbanization. The results of this study have significant implications for urban planning.     

城市交通干道降雨径流中PAHs的污染特征

以上海、温州市典型交通干道地表径流为研究对象,分析了样品中16种溶解态和颗粒态PAHs浓度,了解了城市交通干道降雨径流中PAHs污染特征及其动态变化过程.结果表明,径流中∑PAHs(包括溶解相、颗粒相)浓度范围为919.8～16711.6ng·L-1,溶解相中PAHs浓度要远低于颗粒相(分别为4.9～1558.0ng·L-1,635.4～16624.0ng·L-1).通过对3场降雨事件中PAHs浓度随降雨过程变化的研究,可以发现并不是所有道路径流都有初期冲刷效应,初期冲刷的产生受雨前干期、降雨强度以及径流量等因素共同作用,因此简单拦截初期径流并不能十分有效地降低PAHs污染负荷.径流中PAHs在颗粒相-水相间的分配系数Kp值为2.3×104～2.5×106L·kg-1,随着悬浮颗粒物含量增加而减少,这可能跟径流过程中颗粒物粒径组成有关.     

聊城市城市地表径流污染负荷估算

基于ArcGIS软件,依据土地利用、土壤类型等遥感数据生成聊城市东昌府城区的土地利用图,统计不同土地利用类型的面积,将研究区域按不同功能分为居住区、交通区、工业区、绿化用地、公共建设用地和未利用土地,选择不同CN(Curve Number)值,采用SCS径流曲线模型计算2009年的径流深度和年径流量。结果表明:聊城市东昌府区2009年不同功能分区的降水径流深度分别为272.47 mm、465.00 mm、277.16 mm、30.68 mm、128.47 mm、167.51 mm,同时,根据研究区域内悬浮物(SS)、化学需氧量(COD)、总氮(TN)、总磷(TP)等污染物的平均浓度,估算得出它们的负荷量分别为8 558.8 t、2 415.32 t、201.29 t、10.08 t。     

三峡库区典型退耕还林模式土壤养分流失控制

选择三峡库区典型退耕还林模式,包括园地(茶园)及林地(板栗)与原有坡耕地对照,观测并分析其土壤养分(氮磷)输出途径及数量情况,以评估实施退耕还林工程对流域土壤养分输出的影响.结果表明:1退耕后土壤养分氮磷年流失量(包括随泥沙和地表径流流失的量)减少;总氮(TN)年输出量从大到小依次为坡耕地(2 444.27 g·hm-2)茶园地(998.70g·hm-2)板栗林地(532.61 g·hm-2);总磷(TP)为坡耕地(1 690.48 g·hm-2)茶园地(488.06 g·hm-2)板栗林地(129.00 g·hm-2);与坡耕地比较,退耕还林模式(园地、林地)总氮、总磷年输出载荷分别减少了68.68%和81.75%.2茶园地、板栗林地与坡耕地相比,土壤养分速效态氮流失量明显减少,硝态氮(NO-3-N)输出总量依次为坡耕地(113.79g·hm-2)茶园地(73.75 g·hm-2)板栗林地(56.06 g·hm-2);铵态氮(NH+4-N)养分输出次序为茶园最大(69.34 g·hm-2),坡耕地次之(52.45 g·hm-2),板栗林地最小(47.23 g·hm-2).3硝态氮、铵态氮主要通过地表径流输出,所占总量比例分别为91.4%和92.2%;总氮和总磷主要通过泥沙输出,所占总量比例分别为86.6%和98.4%.通过退耕还林等措施,该地区地表径流以及土壤侵蚀输出明显减少,土壤养分流失得到有效控制.