都市农业村域地下水非点源氮污染及其风险评估

以上海市南汇区新场镇果园村为研究区域,连续监测了该村域地下水中的总氮和"三氮"含量变化。结果表明:该村域地下水中的"三氮"主要以NO3--N形态存在,平均浓度范围为1.43～13.71 mg/L;地下水氮污染与土地利用类型有关,居民区地下水中NH4+-N污染最为严重,平均浓度范围为0.074～0.457 mg/L;河道旁地下水中NH4+-N污染较轻;果园旁和河道旁地下水总氮污染程度相当,平均浓度范围分别为33.67～62.57 mg/L,33.05～65.04 mg/L。均比居民区地下水污染严重。同时研究发现,该村域地下水中的总氮和"三氮"含量也受降雨强度和降雨时间的影响。同时,采用模糊综合评价法评价了该区域地下水氮污染的环境风险。     

喀斯特山区不同农作方式下土壤质量变化对浅层地下水质量的影响

选择贵州中部喀斯特山区普定县猫洞小流域,对长期受不同农作行为影响的区域（低复种旱作区、高复种旱作区、高复种复合农作区）土壤和浅层地下水进行采样和分析。结果表明,不同农作区浅层地下水化学组分明显不同,从低复种指数的旱作区、高复种指数的旱作区到高复种指数的复合农作区,浅层地下水中的NO3^-、NH4^＋、PO4^3-、高锰酸钾指数和SO2^4-的含量依次增大,呈显著上升趋势,在高复种指数农作区浅层地下水中氮磷含量更高;在浅层地下水中,NO3^-含量受土壤有机质、腐植酸、全氮和碱解氮的影响最大,PO4^3-含量受土壤全磷、碱解氮、CEC的直接影响大;Cl^-对浅层地下水影响不明显。不同农作方式对地下水的NO3^-、NH4^＋、高锰酸钾指数的贡献存在差异,可见喀斯特特殊的双重水文结构使水环境质量易受土壤质量等环境因素影响,特别是浅层地下水更易受到污染。     

水稻覆膜旱作栽培方式对稻田地下水水质的影响

对水稻覆膜旱作条件下稻田地下水水质变化作了动态检测。结果表明,与常规淹水栽培区相比,覆膜旱作区水稻不仅极显著增产,而且稻田地下水总氮含量,包括NH4^ -N、NO3^--N、特别是NO2^-N含量明显降低,氯根（Cl^-)含量也较低,地下水总磷含量、水溶性磷含量有所降低,但总体上相差不大。水稻覆膜旱作栽培方式能对施肥造成的稻田地下水水质非点源污染起到良好的控制效果。     

喀斯特山区不同土地利用方式下土壤质量变化及其对水环境的影响

对贵州中部喀斯特山区不同土地利用方式(阔叶林地、灌木林地、灌丛草地、耕地)对土壤、地表径流和浅层地下水进行采样与分析。结果表明,在喀斯特山区土地利用模式从阔叶林地—灌木林地—灌丛草地方向的演变过程中,土壤有机质、速效氮磷钾、交换性钙镁含量出现明显的下降,粘粒含量增加,土壤质量出现退化,耕地有机质含量明显低于林地和草地;耕地地表径流中SO42-,NH4 ,PO43-,COD均显著高于林地和草地;浅层地下水的SO42-,NH4 ,NO3-,PO43-,COD也显著增加;土地利用由林地变为耕地后,地下水质量出现一定程度的下降。     

喀斯特山区不同土地利用方式下土壤质量变化及其对水环境的影响

对贵州中部喀斯特山区不同土地利用方式（阔叶林地、灌木林地、灌丛草地,耕地）对土壤、地表径流和浅层地下水进行采样与分析。结果表明,在喀斯特山区土地利用模式从阔叶林地-灌木林地-灌丛草地方向的演变过程中,土壤有机质、速效氮磷钾、交换性钙镁含量出现明显的下降,粘粒含量增加,土壤质量出现退化,耕地有机质含量明显低于林地和草地;耕地地表径流中SO4^2-,NH4^＋,PO4^3-,COD均显著高于林地和草地;浅层地下水的SO4^2-,NH4^＋,NO3^-,PO4^3-,COD也显著增加;土地利用由杖地变为耕地后,地下水质量出现一定程度的下降。     

雨季喀斯特小流域氮输出特征及其受降雨的影响

以黔中典型喀斯特农业小流域后寨河流域为研究区域,探讨喀斯特小流域氮素输出形态特征及降雨对氮素输出的影响。通过对流域内落水洞、地表水和地下水水样各形态氮素的浓度进行监测,估算雨季氮素输出量,结合降雨量数据分析氮输出受降雨的影响。结果表明:(1)后寨河喀斯特小流域水体氮含量明显高于我国主要河流,流域地下水出口溶解性总氮(TDN)浓度均值为6.5mg/L;地表水出口TDN浓度均值为7.3mg/L。(2)氮素输出的主要形态为硝态氮(NO_3~--N),铵态氮(NH_4~+-N)、亚硝态氮(NO2--N)以及有机态氮(DON)输出占比极低。(3)流域内TDN,NO_3~--N,NH_4~+-N,NO2--N,DON雨季输出量估算值分别为55.13,52.12,0.40,0.01,2.61t。(4)持续性的多日降雨加速了水体氮素流失强度,流域上游水体硝态氮浓度在降雨事件发生后呈上升趋势,随着降雨事件的停止而呈下降趋势;流域总出口因降雨而产生的硝态氮浓度变化具有一定的滞后性。     

盐碱地农田排水对查干湖承泄区的水质影响评价

为了评价盐碱地农田排水对承泄区的水质影响,该文选取吉林省前郭灌区的农田排水和查干湖承泄区为研究对象,通过2009－2010年水稻生长季每月定期的野外取样、实验分析水样的K+、Na+、Ca2+、Mg2+、SO42-、Cl-、CO32-、HCO3-、总氮、总磷和化学需氧量,研究了查干湖灌溉灌排系统至承泄区相关排水水质的时空变化,并对查干湖水质进行了评价。结果表明,查干湖承泄区对灌排系统的各水质指标有一定的累积效应。目前查干湖水体pH值平均在7.87;钠吸附比最大值（3.59 (mmolc/L)1/2）出现在5月份泡田洗盐期;总氮含量为1.22 mg/L,低于近12年平均值1.56 mg/L;6月份总磷含量最高,达0.28 mg/L。除化学需氧量超标外,其他水质参数未达到浓度限值,但在丰水期查干湖水体已属IV类水质。该研究可为查干湖承泄区的生态环境预警提供理论基础。     

安徽老山亚热带常绿阔叶林降雨中氮和可溶性有机碳的动态变化

对安徽老山自然保护区亚热带常绿阔叶林降雨中可溶性碳和氮动态进行了研究。结果表明,该地区大气降雨pH为6.82,呈中性;TOC含量为3.330mg/L,NH4+-N含量为0.405mg/L,NO3-N含量0.501mg/L。降雨经过冠层后,物质成分的含量发生显著改变。穿透雨的TOC含量为10.498mg/L,NH4+-N含量为0.454mg/L,NO3-N含量为0.959mg/L,分别是林外降雨的3.15,1.12,1.91倍。树干径流的TOC含量为21.157mg/L,NH4+-N含量为0.972mg/L,NO3-N含量为1.040mg/L,分别是林外降雨的6.35,2.40,2.08倍。TOC及氮含量的低值都是出现在夏季生长旺盛期,可能与树木在此期需要大量的养分来维持有关,而林外雨各物质含量的出现低值主要与降雨强度、降雨量有关。     

上海市都市农业区域地下水磷素非点源污染特征研究

为研究都市农业区域非点源磷污染对地下水的影响,选择上海市南汇区新场镇果园村的地下水为研究对象,并于2009年7月到9月雨季对该区域地下水进行连续监测。研究结果表明:该区域地下水中磷的形态以水溶性有机磷为主,水溶性总磷含量介于0.75～1.97mg/L之间,平均浓度为1.31mg/L,磷酸盐浓度在0.22～0.62mg/L之间,平均浓度为0.42mg/L。水质低于地表水Ⅴ类标准(0.4mg/L),地下水污染水平已严重超标,不宜饮用。地下水中非点源磷的迁移与土地利用类型相关,果园旁地下水中磷素浓度在降雨前后变化明显。同时,降雨时地表径流加剧磷素流失,农田施肥、水体渗漏均会加剧地下水磷素非点源污染。     

三峡水库成库初期氮、磷分布特征

三峡库区及其上游区是我国水土流失的重要地区。2003年6～12月三峡水库成库后，在三峡水库设置6个水平监测断面和2个垂直断面，每月对营养盐（NH3－N，NO2－N，NO3－N，TN，TP）进行浓度监测。结果表明，6个测点表层水NH3－N，NO2－N、NO3－N，TN，TP含量均值分别为0.11mg／L，0.019mg／L，1.28mg／L，1.62mg／L，0.13mg／L。沿水流方向TN浓度逐渐增高，TP浓度逐渐降低。在同一位置垂直方向按3个不同水深（表层、0.6倍水深和0.8倍水深）设置测点。连续7个月测试结果表明，营养盐在垂直方向上差异不明显。总磷浓度变化与流量变化有很大关系，总磷浓度最大值均出现在丰水期，最小值为枯水期。     

贵州草海耕地土壤与农作物中DDTs和HCHs残留及污染特征

采集草海流域周边成熟期整株农作物及土壤样品,分析测试其中DDTs和HCHs的含量,对比研究了土壤和作物中DDTs和HCHs污染水平及其在作物中富集能力。结果表明：研究区域土壤中HCHs和DDTs残留检出率均为100％,残留范围分别为0．06～16．66μg·kg^-1和0．08-39．77μg·kg^-1,土壤中HCHs和DDTs的残留量均小于国家土壤环境质量一级标准;三种农作物中DDTs、HCHs及∑（DDTs,HCHs）残留量差异显著,HCHs含量最高的是玉米,DDTs和（DDTs,HCHs）最高的是马铃薯;三种农作物中HCHs和DDTs残留的风险系数均为1．1,属于低度风险,农作物中DDTs、HCHs及∑（DDTs,HCHs）的安全指数IFSc均小于1,DDTs和HCHs残留量对三种农作物安全影响的风险是可以接受的。     

我国亚热带山地丘陵区特征及开发中的有关问题

我国亚热带山地丘陵区，山多地少、人口众多、经济基础薄弱，生态环境严重恶化，障碍着区内经济的发展，区内开发应按照以下几个方面搞好：１、协调山－林－地－人的关系；２．调整粮食－林牧－融渔关系；３．改善生产－生活－生态环境。４．提高生态－经济－社会效益。     

百菌清和毒死蜱在大棚番茄中的分布与降解特征

大棚和露地环境下,分别对番茄植株一次性喷洒推荐剂量的百菌清（CHT）和毒死蜱（CHP）,研究喷药后两周内农药在番茄根、茎、叶和果实中分布的持久性及其动态降解规律。实验结果表明,百菌清在大棚番茄中的残留浓度分布呈现为叶片垌果实〉茎〉根;毒死蜱呈现为叶片〉果实垌茎〉根。大棚番茄各部位的最高残留浓度出现时间滞后于喷药时间8~60h;空间浓度分布上表现为大棚中间区域浓度高于两侧,这与棚内的空气对流有关。大棚番茄果实中百菌清和毒死蜱的残留半衰期分别为5.8d和7.2d,明显高于文献报道。     

Degradation and development of peatlands in Peninsular Malaysia and in the islands of Sumatra and Borneo since 1990

In this study, we investigated the extent of peatland degradation and development in Peninsular Malaysia and in the islands of Sumatra and Borneo, in the western part of insular Southeast Asia, since 1990. Furthermore, carbon emissions caused by these land cover changes were estimated in order to evaluate their contribution to global climate change. High resolution Landsat (30 m spatial resolution) and Satellite Pour l'Observation de la Terre (SPOT; 10–20 m) satellite images were used to derive information on land cover in 1990 and 2008. Analysis of land cover changes since 1990 revealed remarkable reduction and degradation of peatswamp forest ecosystems. In less than 20 years, 5·1 Mha of the total 15·5 Mha of peatland had been deforested (11·6 Mha → 6·5 Mha; 75 per cent → 42 per cent) and the great majority of the remaining forests had been selectively logged. Simultaneously, area covered by unmanaged secondary growth ecosystems had doubled to nearly a quarter of all peatlands and industrial plantations had expanded dramatically (0·3 Mha → 2·3 Mha; 2 per cent → 15 per cent). It was conservatively estimated that these changes have caused minimum of 1·5 Gt carbon emissions into the atmosphere since 1990. Currently, peatlands of the study area emit at least 81 Mt of carbon (equivalent to 300 Mt of carbon dioxide) on annual basis due to mere peat decomposition. Thereby, it was concluded that peatland degradation and development in insular Southeast Asia during the past two decades have not only put the existence of Southeast Asian peatswamp forest ecosystems in danger but it has also caused globally significant carbon emissions and created a constant source of carbon dioxide. Copyright © 2010 John Wiley & Sons, Ltd.     

红薯对Pb、Cd的吸收累积特征及根际土壤Pb、Cd形态分布研究

为了解土壤在Pb、Cd单一以及复合污染条件下红薯对Pb、Cd的吸收和积累规律,通过盆栽试验对红薯地上部和地下部的生物量和重金属含量进行测定,分析了单一及复合污染土壤中重金属Pb、Cd形态分布特点。结果表明,相对于对照,较低浓度的Pb、Cd能显著促进红薯的生长（P〈0.05）,Pb超过50mg.kg-1、Cd超过3mg.kg-1时,红薯生长受到显著抑制（P〈0.05）,Cd是影响红薯生长的主要因素;随着试验处理浓度的升高,红薯体内重金属含量也随之升高,二者之间存在极显著的相关性（P〈0.01）,Pb、Cd共存对红薯吸收累积Pb、Cd具有明显的交互作用,Pb促进Cd向地上部转移,Cd促进Pb在地下部积累。根际土壤中Pb、Cd以可交换态与碳酸盐结合态为主,二者均占总量的55以上,在复合污染条件下,Pb浓度为50mg.kg-1时其活性系数显著高于其他Pb处理（P〈0.05）,并在很大程度上促进有效态Cd含量的增加。     

Immobilization and species of heavy metals in soils in the absence and presence of rhizobia

Abstract

The effect of bacterial inoculation of Rhizobium fredii HN01 on the immobilization and speciation of Cu, Zn, and Cd was studied in Red and Cinnamon soil which are typical Chinese soils. The soil was mixed with bacterial suspension for one week followed by an immobilization of each heavy metal for another week. The total binding and fractionation of heavy metals in soils were analyzed. As compared with the control, the retention of total Cu, Zn, and Cd in Red soil increased by 28, 16, and 28%, respectively, in the presence of rhizobia. The amount of exchangeable, NH₄OAc-extractable, Mn oxides-bound and organic matter-bound Cu increased by 23–123%. There were significant decrease of exchangeable Cu and marked increases of NH₄OAc-extractable and Mn oxide-bound Cu in Cinnamon soil with the presence of rhizobial cells, although no changes for the total retention of Cu were observed. The amount of exchangeable Zn in Red soil-rhizobia composite was 20% greater than that of the no-rhizobia soil. Addition of rhizobia also increased exchangeable Cd and specifically-adsorbed Cd by 25 and 93%, respectively, in Red soil. No considerable differences were found for the total immobilization of Zn and Cd as well as their distribution in various solid fractions of Cinnamon soil in the absence and presence of rhizobial cells. In terms of soil components, it is assumed that bacterial biomass had a relatively less impact on the species of heavy metals bound with Fe oxides. Results suggested that the retention and speciation of heavy metals in soil are governed largely by the interactions of bacteria with various inorganic and organic soil constituents. The data are useful in understanding the impact of microorganisms on the behavior, mobility and transformation of heavy metals in soil environments.     

除草剂莠去津和灭草松单用和混用在土壤中的降解

The application of a mixture of bentazone （3-isopropyl-1H-2,1,3-benzothiadiazin-4（3H）-one-2,2-dioxide） and atrazine （6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine） is a practical approach to enhance the herbicidal effect. Laboratory incubation experiments were performed to study the degradation of bentazone and atrazine applied in combination and individually in maize rhizosphere and non-rhizosphere soils. After a lag phase, the degradation of each individual herbicide in the non-autoclaved soil could be adequately described using a first-order kinetic equation. During a 30-d incubation, in the autoclaved rhizosphere soil, bentazone and atrazine did not noticeably degrade, but in the non-autoclaved soil, they rapidly degraded in both non-rhizosphere and rhizosphere soils with half-lives of 19.9 and 20.2 d for bentazone and 29.1 and 25.7 d for atrazine, respectively. The rhizosphere effect significantly enhanced the degradation of atrazine, but had no significant effect on bentazone. These results indicated that biological degradation accounted for the degradation of both herbicides in the soil. When compared with the degradation of the herbicide applied alone, the degradation rates of the herbicides applied in combination in the soils were lower and the lag phase increased. With the addition of a surfactant, Tween-20, a reduced lag phase of degradation was observed for both herbicides applied in combination. The degradation rate of bentazone accelerated, whereas that of atrazine remained nearly unchanged. Thus, when these two herbicides were used simultaneously, their persistence in the soil was generally prolonged, and the environmental contamination potential increased.     

Presence and dispersal of infective Frankia in peat and meadow soils in Sweden

Summary Use of the N₂-fixing grey alder, Alnus incana (L.) Moench, as a short-rotation crop for energy production is currently being explored. To evaluate the need for inoculation of alders, the distribution of infective propagules of Frankia in the soil at potential sites for alder plantations was examined. Uninoculated grey alder seedlings were grown in three types of soil. Frequent nodulation was found in a meadow soil which had been free from actinorhizal plants for nearly 60 years, but the alder seedlings failed to nodulate in peat soil from two different bog sites. One of these bogs had been exploited for peat and the surface layer of the peat had been removed, so that the soil samples were taken from deep layers of the peat. At the other site, an area of cultivated peat, there were no infective propagules of Frankia in plots without alders; the infective Frankia was present in plots only where it had been introduced by inoculated alders. There was no detectable air-borne dispersal of Frankia. Instead, water movement might account for the dispersal of Frankia in peat. Although the apparent absence of Frankia in these peat soils necessitates inoculation of alder seedlings before planting out, this makes it possible to introduce and maintain Frankia strains with selected beneficial characteristics, since there is no competition from an indigenous Frankia flora.     

Sources of sulphate and acidity in wetlands and lakes in Nova Scotia

There is a declining gradient of wet SO₄ deposition from south to north in Nova Scotia with the highest values being in the south, along with a localized increase around the Halifax metropolitan area, due to local SO₄ emission. Edaphic conditions such as drainage from soils containing gypsum or drainage on disturbed rocks containing pyrite, provide additional SO₄ to surface waters.Acidity is usually absent in the former (pH > 7.0) and very high in the latter (as low as pH 3.6). By contrast peaty, organic drainages release water low in SO₄ during the growing season but they release high amounts of organic anions (A?), consequently, these waters maintain decreased pH values, usually < 4.5. A study of over 80 wetlands and lakes during the ice free period in Nova Scotia showed that sea salt corrected SO₄ concentrations range from 45 ueq L^?1 in the south end of the province, ～30 ueq L^?1 in the Kejimkujik area and < 17 ueq L^?1 in the northern areas with values > 85 ueq L^?1 in the Halifax area, reflecting the atmospheric deposition pattern of SO₄ The SO₄ concentrations may be > 2000 ueq L^?1 in drainages containing gypsum, > 700 ueq L^?1 in drainages over pyrite bearing socks but < 20 ueq/L^?1 in streams draining bogs. The SO₄ concentrations change considerably during the non-growing season when the ground is saturated with water or frozen, and the runoff is high (snow and rain often alternate in winter). Under such conditions SO₄ concentration drops in the two former cases and increases in bog drainages, accompanied with a considerable drop in (A?) concentrations. Care should be taken when interpreting SO₄ concentrations in surface waters in Nova Scotia with respect to atmospheric SO₄ deposition.