农田土壤铜污染评价和油菜铜积累特征研究

以湖北省大冶市农田土壤和油菜为研究对象,调查了10个区域40个农田土壤样品的Cu污染状况,采用单项污染指数法对土样的Cu污染现状进行评价;采用改进BCR法分析了其中种植油菜的22土样Cu的赋存形态,并对油菜各部位Cu含量进行了测定,结合富集系数和转运系数,分析了Cu在土壤-油菜系统中的迁移累积规律。结果表明,以湖北省土壤背景值评价,土壤受到不同程度的Cu污染,重污染所占比例最高;以国家土壤环境质量二级标准(GB15618-1995)评价,污染等级以轻污染为主,且有25%的土壤未污染;污染最严重的3个区域是铜绿山、大箕铺和龙角山。油菜土壤中Cu的形态分布规律为残渣态可还原态可氧化态酸溶态,酸溶态占全量的比例与p H有显著的负相关关系,相关系数r=-0.471(n=22)。油菜各部位Cu含量分布呈现根壳籽茎的规律,Cu主要累积在油菜根部,土壤-籽富集系数均值仅为0.11;9个油菜样籽粒的Cu含量超过了食品安全限值,籽粒的Cu含量与土壤酸溶态Cu含量之间的相关性最强。     

不同性质农田土壤中铜的可提取性与生物有效性及毒性

以重金属总量为基础的土壤环境质量标准已不适用于当前土壤管理的需求,基于重金属生物有效性的生态风险评估和环境阈值研究对土壤重金属环境质量标准的修订具有重要的指导意义。本研究选取黑土、潮褐土和脱潜水稻土3种不同性质的农田土壤,开展模拟铜(Cu)污染的生物毒性试验,采用HNO₃、EDTA-Na₂、NH₄OAc和CaCl₂ 4种不同浸提能力的化学试剂进行土壤有效态Cu提取,探讨Cu可提取性与生物有效性及毒性的关系;并通过敏感性生态物种生菜和赤子爱胜蚓的Cu暴露试验,推导基于化学提取有效态的土壤Cu生态毒性阈值。研究结果表明:HNO₃(41.4%)和EDTA-Na₂(56.8%)对3种土壤中Cu的平均提取效率显著高于NH₄OAc(0.12%)和CaCl₂(8.70%)。CaCl₂提取态Cu含量与生菜Cu富集量和毒性效应之间存在显著或极显著相关,HNO₃提取态Cu含量则能很好地指示...     

中国三北地区冻结滞水资源对生态环境建设的效应研究

依据野外观测和室内模拟实验研究资料分析冻结滞水对西北地区生态环境建设的效应,冻结滞水是指冬季冻结作用在包气带冻土层内形成的固态地下水,具有形成机制独特、富水性倒置和独立的水盐动态特征,对生态环境建设产生双重效应.冻结滞水量比冻结前土壤含水量一般增加8%～25%,最高可达39.51%,冻胀区可达300%.在三北地区冻结滞水是天然和人工树木等植被越冬、春季繁衍期间水分代谢均衡的主要水资源,甚至是唯一水资源,是三北地区生态环境建设成败的主导因素之一.当冻结滞水量平均＜5%时,天然林和人工林等植被衰亡,可加速荒漠化,当冻结滞水量达过饱和状态时,则易形成沼泽化、盐渍化等不良地质现象,导致生态环境恶化.控制冻结滞水量对西北地区建设林业工程、优化生态环境和可持续发展至关重要.     

砂质农业土壤养分积累和迁移特点的研究

研究表明，砂质土壤开垦农用后，土壤有机质和保肥性（CEC）明显下降。除大棚蔬菜地外，施用的氮和钾肥不易在土壤中积累，很容易在短时间内沿剖面迁移至地下水，或随地表径流迁移至周围水体。但磷可以活性较高的可提取态形式积累在砂质土壤剖面中，并可逐渐随水进入地下水或迁至地表水，对环境造成危害。长期施用化肥的砂质农地地下水中磷、氮浓度可达到较高的水平。田间观测和模拟淋洗试验表明，砂土中养分极易随水迁移，高浓度的养分流失常发生在施肥后的降雨过程中。因此在砂质土壤上应避免高量施肥，肥料宜少量多次施用，不宜在雨前施用肥料。     

浙江省葡萄园土壤铜的积累与生物有效性研究

为了解长期种植葡萄喷施波尔多液对土壤铜积累的影响,以浙江省为例,采集了不同种植年限的代表性葡萄园土壤,分析了土壤中铜的全量和有效态含量。结果表明,喷施波尔多液可促使铜在葡萄园土壤中明显积累,葡萄园土壤中铜含量明显高于一般的农田土壤。随着葡萄园种植年限的增长,土壤中全铜显著增加,表土年铜积累速率平均为4.18 mg kg-1。与对照土壤相比,葡萄园土壤有效态铜随园龄的增幅比其全量更为明显;有效态铜与全铜和有机质含量呈正相关,与p H值呈负相关。葡萄园土壤中铜具有明显的表聚特点,在土壤剖面中自上而下含量逐渐降低。     

碱稳定污泥污水对土壤可提取有机碳和铜的影响

An incubation experiment was conducted to evaluate the potential for water contamination with sludge-derived organic substances and copper following land application of alkaline-stabilised sewage sludge. Two contrasting sludge-amended soils were studied. Both soils were previously treated with urban and ruralalkaline biosolids separately at sludge application rates of 0, 30 and 120 t ha^-1 fresh product. The air-driedsoil/sludge mixtures were wetted with distilled water, maintained at 40 % of water-holding capacity and equilibrated for three weeks at 4 ℃ before extraction. Subsamples were extracted with either distilled wateror 0.5 mol L^-1 K₂SO₄ solution. The concentrations of organic C in the aqueous and chemical extracts were determined directly with a total organic carbon (TOC) analyser. The concentrations of Cu in the twoextracts were also determined by atomic absorption spectrophotometry The relationship between the two extractable organic C fractions was examined, together with that between extractable organic C concentration and extractable Cu concentration. Application of alkaline biosolids increased the concentrations of soil mobile organic substances and Cu. The results are discussed in terms of a possible increase in the potential for leaching of sludge-derived organics and Cu in the sludge-amended soils.     

向日葵对土壤中铜的积累作用研究

温室内不同Cu浓度添加土壤的向日葵盆栽试验表明,向日葵植株的部分生物学性状如地上部干物质量、地下部干物质量、最大单叶面积随土壤中Cu浓度的增加而降低,土壤中添加20mg/kgCu对向日葵根部生长抑制作用最大,而植物高度在添加100mg/kgCu浓度时最高。且不同Cu浓度处理下向日葵对Cu的积累能力不同,但植物各部分Cu含量均随土壤中添加Cu浓度的增加而增加,但在100mg/kgCu浓度处理下,向日葵对Cu的积累主要集中在根部,地上部分Cu含量很低,在200mg/kgCu浓度处理下,向日葵叶中Cu含量超过根部,达857±297mg/kg干重,Cu积累的叶根比达1.27,说明当土壤Cu浓度较高时,Cu在向日葵地上部有较高的Cu积累,集中收获植株地上部分,可移出土壤中的过多有效铜,但生长受到抑制。使用向日葵修复高浓度Cu污染土壤时,还需考虑采用其他手段接种根际微生物、转基因、设施农业环境工程技术等来增加其生物产量。     

长期施用有机肥对土壤和糙米 铜、锌、铁、锰和镉积累的影响

设施氮、磷、钾肥（NPK）、施氮、磷、钾肥兼稻草还田（NPKS）、施氮、磷、钾肥兼2倍稻草还田（NPKS2）、施氮、磷、钾肥兼施紫云英（NPKG）和施氮、磷、钾肥兼施猪粪5个处理的长期定位试验,探讨了长期施用有机肥对土壤和糙米铜、锌、铁、锰和镉含量的影响。结果表明,土壤全铜、全锌和全镉因秸秆还田或施用紫云英、猪粪有明显提高,尤其是施用猪粪,土壤全铜、全锌和全镉较仅施用氮、磷、钾肥分别增长53.6%、23.6%、406.2%,达到极显著水平; 而全铁和全锰各处理间没有显著差异。长期施用有机肥增加了土壤有效态铜、锌和镉含量,其中施用猪粪土壤有效铜、锌和镉含量增加最为显著,分别比NPK处理增长了335.9%、320.8%、421.4%。长期施用猪粪明显地增加了糙米中镉含量,并超过国家卫生标准。长期施用畜禽粪便类的有机肥对农产品的安全应予以足够的关注。     

Mobility of copper and zinc fractions in fungicide-amended vineyard sandy soils

The purpose of this study was to evaluate the mobility of copper (Cu) and zinc (Zn) in the profile and distribution of sandy soil fractions from vineyards. Soil samples were collected from two vineyards of different ages (14 and 30 years) and a natural field area in the south of Brazil. The chemical characteristics, Cu levels and Zn levels, were analyzed in the soils by extraction with ethylenediamine tetraacetic acid (EDTA) using the 3050B method of USEPA and by chemical fractionation. Cu and Zn were accumulated in the vineyard soils, especially in the uppermost soil layers and in the soil from the oldest vineyard. Approximately, 75% of the total Cu was extracted by EDTA, but only 30% of the total Zn was extracted by EDTA. Most of the Cu, especially in the oldest vineyard, was distributed in the mineral-associated fraction, which is characterized by low geochemical mobility, but another important part of the Cu was distributed in the soil organic matter. Most of the Zn in the soil was distributed in the residual and mineral-associated fractions, which are characterized by low mobility and have potential for causing toxicity to plants.     

搞好海河流域水土保持工作 维护京津及周边地区生态安全

自2000年以来,国家在海河流域相继启动实施了京津风沙源治理工程、21世纪初期首都水资源可持续利用项目、国债水土保持工程等一批国家重点工程,使全流域水土保持生态建设获得长足发展。一是建立了流域机构与地方有关部门之间职责明确、协调有序的工作机制;二是形成了符合不同区域实际的、科学的水土流失综合防治技术路线;三是适应新形势发展要求,丰富了水土保持生态建设内涵;四是水土流失综合防治取得了明显成效。对新时期海河流域的水土保持工作提出了五点要求。     

海河流域大气水汽输送的年际与年代际变化

The seasonal mean atmospheric precipitable water and water vapor transport over the Haihe River Basin （HRB） in North China with a focus on their interannual to interdecadal variability, and then the relationships of the interannual and interdecadal variability of the water cycle over the HRB to the Pacific Decadal Oscillation （PDO） and E1 Nino-Southern Oscillation （ENSO） phenomena were investigated using the observational and National Centers for Environmental Prediction （NCEP） reanalysis data. There was a strong interdecadal variability for the water cycle （such as precipitation and water vapor transport） over the region, with an abrupt change occurring mostly in the mid 1970s. The intensity of the East Asian summer monsoon largely affected the atmospheric water vapor transport. Generally, the net meridional convergence of the water vapor flux over the region was relatively large before 1965, and it declined gradually from then on with a further notable decrease since mid 1970s. Zonal water vapor transport was similar to meridional, but with a much smaller magnitude and no noteworthy turning in the mid 1970s. Results also suggested that the wind field played an important role in the water vapor transport over the HRB before the mid 1960s, and the interdecadal variability of the water cycle （precipitation, water vapor transport, etc.） in the summer was related to the PDO; however, interannual variation of the water vapor transport could also be related to the ENSO phenomena.     

石羊河流域天然植被适宜生态需水量估算

基于遥感手段并运用ArcGIS 9.3软件统计获得石羊河流域1987,2000及2010年3期各类型天然植被面积数据,采用阿维里扬诺夫估算方法对石羊河流域各县区天然植被的生态需水量进行了估算。结果表明,石羊河流域1987,2000及2010年天然植被适宜生态需水量分别为2.43×10⁹,2.34×10⁹,2.06×10⁹ m³,其中各县区天然植被适宜生态需水量由多到少依次为:肃南县> 天祝县> 永昌县> 民勤县> 古浪县> 凉州区> 金川区。石羊河流域林地、草地的生态需水量基本各占总需水量的1/2,但各县区林地、草地生态需水量的百分比差异明显,流域天然植被的水分利用率介于2.74~16.55 kg/(hm²·mm)。通过对石羊河流域3期天然植被适宜生态需水量的研究发现,流域天然植被无论从总需水量还是各优势盖度的需水量上均呈现减少趋势,因此确定天然植被的适宜生态需水量,对区域水资源的合理配置和科学制定生态恢复方案具有重要的现实意义和借鉴作用。     

黄河流域主要农作物的降水盈亏格局分析

以1961—2000年的气象资料为数据基础，采用FAO 1998年推荐使用的Penman—Monteith模型和参考作物法，对黄河流域不同类型旱农地区主要农作物的降水盈亏格局进行了分析。结果表明：黄河流域大部分地区冬小麦全生育期多年平均缺水量在250～500mm，且由南向北缺水量有依次递增的趋势，主要反映了冬小麦全生育期降水量与需水量的双重影响；夏玉米全生育期缺水量较多的地区为陕西省关中地区，约为200mm左右，由此向东缺水量值逐渐减少；春小麦全生育期多年平均缺水量基本上是从南向北逐渐升高，缺水量在200—500mm，显然是受降雨与需水两方面的双重影响；春玉米全生育期多年平均缺水量分布则是从南部向北部递增，亏缺量在0～400mm。     

基于河流生态类型划分的海河流域平原河流生态需水量计算

根据河流现有生态状况,首次将海河流域平原河流划分为干涸沙化、水质污染和生境破坏三种类型,并针对不同类型河流特点和修复目标,分别用植被需水定额法、75%保证率最枯月平均流量法、生物空间最小需求法和槽蓄法计算了生态需水量。结果表明,海河流域平原河流最小生态需水量为18.12亿m3,相当于流域多年平均流量的8.4%。最后将上述四种计算方法分别与Ten-nant法进行了比较。用植被需水定额法计算的干涸沙化型河流生态需水量结果约占多年平均径流量的2.4%～5.5%,远小于Tennant法的最小生态需水量;75%保证率最枯月平均流量计算的水质污染型河流所需的生态水量占多年平均径流量的百分比为15%左右,略高于Tennant法计算的最小生态需水量;用生物空间最小需求法计算的滦河生态需水量占多年平均径流量的百分比为6%,接近于Tennant法计算的最小生态需水量;槽蓄法计算的生态需水量结果与河流水量修复目标密切相关。总的说来,本文所采取的计算生态需水量的方法在海河流域是可行的。     

浙江省钱塘江流域生态环境需水量研究

从浙江省钱塘江流域现有的水资源开发利用中存在的生态环境问题出发,探讨了符合钱塘江流域生态环境特点的多年平均适宜生态环境需水内涵,并在此基础上,建立了河道内多年平均适宜生态环境需水和河道外多年平均适宜生态环境需水两个部分的计算模型.模型计算结果表明,钱塘江流域多年平均河道内生态环境需水量为1.59×10~(10)m~3/a,河道外生态环境需水量为6.70×10~9m~3/a,多年适宜生态环境需水总量为2.26×10~(10)m~3/a.研究结果可为浙江省钱塘江流域的生态环境保护、水资源的可持续利用以及湿润区生态环境需水研究提供决策依据.     

Extractability and adsorption of sulphate in soils

Virtually all of the indigenous sulphate (SO₄) in a range of UK soils with moderately high pH values (> 6) was found to be present in the soil solution and, as a consequence, was highly susceptible to leaching. For acid soils containing adsorbed SO₄, the extractability of SO₄ in NaCl and CaCl₂ solutions was dependent on both the ionic strength and cation species. Addition of small amounts (<～ 10^?2M) of either NaCl or CaCl₂ actually decreased the amount of SO₄ extracted, but SO₄ extractability increased sharply with concentrations of NaCl or CaCl₂ higher than about 0.1 M. At a similar ionic strength, more SO₄ was extracted by NaCl than CaCl₂. Sequential extraction with 1 M NaCl removed essentially all of the absorbed SO₄. The release characteristics of SO₄ were very different to those of phosphate and this difference in behaviour is not easily reconciled with the view that SO₄ is chemisorbed, as is phosphate. Except for a few acid soils with high oxide contents, the capacity of the soils to adsorb added SO₄ was quite small. None of the soils with pH values higher than 6 adsorbed a significant amount SO₄. The results raise questions regarding the efficiency of SO₄-containing fertilizers in correcting and preventing S deficiency in situations where leaching is important.     

南方暖湿地区河流生态环境需水量估算

以广东省鹤山市沙坪河生态环境需水为研究对象,从河流水资源规划、开发利用过程中涉及到的生态环境需水问题出发,提出了暖湿地区河流生态环境需水量计算的方法,并计算了各项生态环境需水的数量和比例。其中:基本生态环境需水量0.79 m3/s;水面蒸发需水量0.05 m2/s;输沙需水量0.70 m3/s;稀释净化污染物需水量1.10 m3/s;水土保持需水量1.00 m3/s。沙坪河生态环境需水总量3.64 m3/s,总生态环境需水量约占地表径流总量的38.6%,成果可用于水资源规划与开发利用。     

水土保持对黄河流域生态承载力的影响

 用生态承载力和生态足迹理论,评价人类活动对生态环境的影响。分析和计算显示,黄土高原水土保持综合治理有效地增加了当地和下游引黄灌区的生态承载力。以2000年为例,黄土高原水土保持增加的生态承载力达1444.24万hm2,其中黄土高原当地约占77.74%,黄河下游灌区约占22.26%,说明水土保持对提高黄河流域生态(人口)承载力的重要作用,以及黄土高原在国家可持续发展战略中的重要地位。