石盘丘小流域不同土地利用方式下土壤氮磷流失形态及通量

为了解三峡库区小流域不同土地利用方式下土壤氮、磷流失特征,为农业非点源污染防控提供科学依据;采用田间试验的方法,研究了三峡库区石盘丘小流域水田、旱坡地、林地、柑橘园和菜地这5种土地利用方式下地表径流不同形态氮、磷流失浓度与通量的特征.结果表明：全氮流失通量的顺序为水田[17.73 kg·（hm²·a）^-1] > 柑橘园[4.86 kg·（hm²·a）^-1] > 旱坡地[4.33 kg·（hm²·a）^-1] > 菜地[4.00 kg·（hm²·a）^-1] > 林地[2.41 kg·（hm²·a）^-1];全磷流失通量的顺序为菜地[4.97 kg·（hm²·a）^-1] > 柑橘园[1.87 kg·（hm²·a）^-1] > 水田[0.93 kg·（hm²·a）^-1] > 林地[0.27 kg·（hm²·a）^-1] > 旱坡地[0.19 kg·（hm²·a）^-1];5种土地利用方式下氮、磷流失主要集中在降雨频繁的4~5月,占全年氮、磷流失总负荷的53.80%~96.52%和56.03%~87.78%;氮流失主要以硝态氮（16.16%~52.70%）的形态流失,全氮流失通量与径流量呈现出显著正相关关系（R²=0.9826）;在菜地中颗粒磷是磷流失的主要形态（83.30%）,但在其他土地利用方式中表现不显著.不同土地利用方式下不同形态氮、磷流失存在显著差异,其中菜地应针对强降雨情况下颗粒磷流失的问题采取措施,水田应避免在降雨集中时期施肥;科学施肥和合理地土地利用方式配置是治理小流域农业非点源污染的重要途径.     

北京2009~2010年冬、春季PM2.5污染特征

针对北京地区冬季和春季PM_2.5污染特征进行研究.于2009年12月～2010年5月在城市点采集24h 大气颗粒物样品,进行颗粒物主要化学组分分析.冬季和春季颗粒物的平均质量浓度分别为（84.97±68.98）μg/m³和（65.25±45.76）μg/m³.冬季和春季颗粒物中二次组分（SNA+SOA）有重要贡献,二次组分分别占颗粒物质量浓度的49%和47%.冬春季重污染时期较强的源排放和低温、低风速、高相对湿度等不利的气象特征使得颗粒物中二次无机离子SNA（NH₄⁺、NO₃^-、SO₄^2-）的比重较干净天明显上升,其中硝酸盐贡献的增强最为显著.同时冬春季有机物中二次有机组分贡献显著.而受一次源的影响,冬春季重污染时期一次有机物的增强.     

HCHs and DDTs in Yellow River of Henan section—a typical agricultural area in China: levels,distributions and risks

The levels, potential sources and ecological risks of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in Yellow River of Henan section, a typical agricultural area in China, were investigated. Surface water samples and suspended particulate matters (SPMs) were collected from 23 sites during two seasons. In wet season, the residues of ∑HCHs (α-HCH, β-HCH, γ-HCH and δ-HCH) and ∑DDTs (p,p′-DDT, o,p′-DDT, p,p′-DDE, p,p′-DDD) ranged from 41.7 to 290 and 4.42 to 269 ng/L in surface water, while those varied from 0.86 to 157 and 1.79 to 96.1 ng/g dw in SPM, respectively. Moreover, in surface water, the levels of HCHs and DDTs in wet season were much higher than those in dry season. The reverse was true for residues of HCHs and DDTs in SPM. Compared with the large rivers in other regions, the levels of HCHs and DDTs in the studied area ranked at high levels and the residual concentrations might cause adverse biological risk, especially for ∑HCHs during wet season. Distributions of HCHs and DDTs delineated that the input of tributaries made a significant effect on the residue of HCHs and DDTs in the mainstream. ∑HCHs in surface water were consist of 26.7 % α-HCH, 30.0 % β-HCH, 37.9 % γ-HCH and 5.45 % δ-HCH and those in SPM contained 5.16 % α-HCH, 22.1 % β-HCH, 60.5 % γ-HCH and 12.2 % δ-HCH on average. Combined with ratios of α-HCH/γ-HCH in surface water (0.70) and in SPM (0.09), the results strongly indicated that lindane was recently used or discharged in the studied area. The mean percentage of DDTs′ isomers were 28.7 % p,p′-DDT, 29.8 % o,p′-DDT, 28.1 % p,p′-DDE and 13.4 % p,p′-DDD in surface water, while those were 12.5 % p,p′-DDT, 31.8 % o,p′-DDT, 30.5 % p,p′-DDE and 25.1 % p,p′-DDD in SPM. The ratios of (DDE + DDD)/∑DDTs and o,p′-DDT/p,p′-DDT revealed that the DDTs in the studied area mainly derived from long-term weathering of technical DDTs residue and the input of dicofol.     

Characteristics of residual organochlorine pesticides in soils under different land-use types on a coastal plain of the Yellow River Delta

The residual levels of organochlorine pesticides (OCPs) were examined in soils covering five types of land use along a salinity gradient on the Yellow River Delta. The most prominent OCPs were dichlorodiphenyltrichloroethane (∑DDT, arithmetic mean = 5.11 μg kg^?1), hexachlorocyclohexane (∑HCH, 1.69 μg kg^?1) and ∑endosulfan (10.4 μg kg^?1). The spatial variability of OCPs composition shifted from γ-HCH and o,p′-DDT dominated pesticides in coastal soils to p,p′-DDE dominated pesticides in inland soils. In different land-use types, the percentages of β-HCH and p,p′-DDE are characterized by more recalcitrant components in decreasing order of vegetable fields, cereal fields, cotton fields, wetlands and tidal flats with increasing soil salinity. However, the less recalcitrant components, γ-HCH and o,p′-DDT, showed an opposite trend. Endosulfan sulfate predominated in all land-use types. Residual levels of β-HCH were affected by soil organic matter. The correlations between γ-HCH and clay content and between p,p′-DDE, o,p′-DDT and salinity might associate with the influence of sediment cotransport by the Yellow River and the density of anthropogenic activities in coastal region. Depth distribution of the OCPs in typical soil profiles also implied that local historical usage and sediment transport by the Yellow River both affected the OCPs residual in this region.     

G蛋白偶联雌激素受体1介导的环境雌激素效应研究进展

环境雌激素进入生物体后,可通过多种方式介导发挥类似内源雌激素的作用,干扰生物体的正常功能,进而对生物体产生毒害作用。其中,基因组方式介导的雌激素效应主要通过与细胞核内的雌激素受体(如ERα和ERβ)结合;而非基因组方式介导的雌激素效应则主要通过与膜雌激素受体结合从而发挥作用。近年来对G蛋白偶联雌激素受体1(GPER1)的研究表明,该受体是区别于雌激素核受体的膜雌激素受体,可单独介导雌激素诱发的非基因组方式雌激素效应,然而目前对其介导的雌激素效应机制研究并不完善。综上,本文结合近年来对GPER1的研究进展,从该受体的发现、特性以及其介导的雌激素效应和相关通路进行了综述。     

运动对2,3,7,8-四氯二苯并二恶英急性暴露大鼠肝脏抗氧化能力的影响

观察8周中等强度游泳运动对2,3,7,8-四氯二苯并二恶英(2,3,7,8-tetrachlorodibenzo-p-dioxin,2,3,7,8-TCDD)急性暴露大鼠肝脏氧化应激的影响。以8周龄雄性Sprague Dawley大鼠为研究对象,将大鼠随机分为玉米油静养组(NC组)、玉米油运动组(EC组)、TCDD静养组(NT)和TCDD运动组(ET组)。将TCDD溶于玉米油中,NT和ET组大鼠按照10μg·kg-1(以单位体重计)腹腔注射TCDD,NC和EC组大鼠注射等量玉米油。正式实验开始后,EC和ET组大鼠进行运动(尾部负重5%游泳30min),每周运动5 d,共8周,NC和NT组大鼠不进行任何运动干预。8周后,称重并宰杀大鼠,收集血清和肝组织样本,待测血清天门冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)的活性;肝组织丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)以及谷胱甘肽过氧化物酶(GSH-Px)的活性。将数据进行多因素方差分析,结果表明,染毒可升高大鼠血清AST的活性,增加肝脏MDA的含量,降低肝脏SOD、CAT和GSH-Px的活性;运动可降低大鼠肝脏GSH-Px的活性;染毒后运动可减少肝脏MDA的含量,升高肝脏SOD、CAT和GSH-Px的活性。研究表明,TCDD急性暴露可导致大鼠肝细胞功能受损,导致大鼠肝脏发生氧化应激。8周有氧运动改善TCDD急性暴露诱导的肝细胞损伤,改善肝脏氧化应激,这可能是运动改善TCDD肝毒性的机制之一。     

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Direct individual analysis using Scanning Electron Microscopy combined with online observation was conducted to examine the S-rich particles in PM_2.5 of two typical polluted haze episodes in summer and winter from 2014 to 2015 in Beijing. Four major types of S-rich particles, including secondary CaSO₄ particles (mainly observed in summer), S-rich mineral particles (SRM), S-rich water droplets (SRW) and (C, O, S)-rich particles (COS) were identified.We found the different typical morphologies and element distributions of S-rich particles and considered that (C, O, S)-rich particles had two major mixing states in different seasons. On the basis of the S-rich particles’ relative abundances, S concentrations and their relationships with PM_2.5 as well as the seasonal comparison, we revealed that the S-participated formation degrees of SRM and SRW would enhance with increasing PM_2.5 concentration. Moreover, C-rich matter and sulfate had seasonally different but significant impacts on the formation of COS.

Open image in new window

     

焦化厂土壤和地下水中PAHs分布特征及其污染过程

以煤炭为原料的焦化厂是环境中PAHs的主要人为污染源. 针对US EPA(美国国家环境保护局)优先控制的16种PAHs,对苏南某生产历史长达16 a、面积为44.58×104 m2的焦化厂土壤样品中的w(PAHs)以及地下水样品中的ρ(PAHs)进行了分析,并采用统计学方法对PAHs的分布规律进行了研究. 结果表明:表层土壤中除二苯并[a,h]蒽外,其他15种PAHs均被检出;w(2~3环PAHs)平均值占w(∑PAHs)平均值的92.6%,明显高于w(4~6环PAHs). 地下水中只检出强亲水性的萘、二氢苊、苊、芴、菲、蒽等6种低环PAHs,但未迁移至厂外. 厂区内土壤和地下水中PAHs污染均具有典型的区域分布特征,并且均为化厂车间最严重. 土壤防污性能的差异使PAHs在3.0 m黏土层〔K_y(垂向渗透系数)=1.28×10-8 cm/s〕中富集. 高环PAHs主要与有机质结合以固相迁移,因w(TOC)随深度增加而下降,部分高w(高环PAHs)点位土壤有机质吸附过饱和,未被吸附的高环PAHs向深层迁移至5.0 m含水层顶板,但因强疏水性未进入7.0 m含水层. 强亲水性低环PAHs以溶解态迁移进入含水层,但因地下水流动缓慢(流速为3.71×10-6 cm/s),PAHs污染区仅集中在化厂车间及其附近区域.      

安徽太平湖旅游地演化过程及机制

湖泊旅游逐渐成为我国湖泊资源利用的重要内容.论文探讨了湖泊旅游地发展的特点,分析了太平湖旅游地的演化过程与机制,结果表明湖泊旅游地发展具有易受干扰性、流域性和综合性的特点;基于Butler 生命周期理论,太平湖旅游地的演化过程可划分为三个阶段:①探索阶段(1970—1990 年),旅游地仅有少量的旅游者和旅游设施,湖泊生态系统处于自然状态;②参与阶段(1991—2005 年),地方政府重视旅游发展,发展观光旅游,建设旅游项目,形成了以水产养殖与旅游业相结合的湖泊资源利用模式;③发展阶段(2006 年至今),政府和外部资本推动太平湖基础设施和重大旅游项目建设,旅游人数和收入大幅增长,重点发展休闲度假旅游,向观光-休闲度假型旅游地转型,形成了旅游与城镇互动的发展格局.太平湖旅游地三个发展阶段体现了由自然发展向追求经济效益发展,再向追求综合效益发展的过程.