对比研究槽式堆肥处理不同畜禽粪便对植物毒性的影响

为揭示槽式堆肥过程中不同畜禽粪便堆肥理化性质的变化及其对植物毒性的影响,分别开展了以羊、牛、鸡、猪粪便与木屑为堆料、为期44 d的好氧槽式堆肥对比试验,采集了不同堆肥期的堆肥样品,测定了堆肥的pH、电导率（EC）、可溶性有机碳（DOC）、硝氮（NO₃^--N）、氨氮（NH₄⁺-N）、全氮（TN）、碳氮比（C/N）、全磷（TP）、全钾（TK）、铜（Cu）、锌（Zn）含量及水堇的相对生长指数（RGI）和种子发芽指数（GI）,并通过相关分析和线性回归拟合,分析了堆肥过程粪便对水堇种子植物毒性的影响机制.结果表明,槽式堆肥过程中,羊粪的高温期持续时间最长,牛粪其次,猪粪和鸡粪最短;堆肥结束时4种粪便均呈弱碱性.堆肥过程中猪粪和鸡粪的EC降低,其他粪便的EC变化幅度较小,各粪便的DOC、NH₄⁺-N含量降低,NO₃^--N、TP、TK、Cu和Zn含量增加,牛粪和鸡粪的C/N逐渐降低,而猪粪和羊粪的C/N呈先升后降的趋势,羊粪和猪粪的TN含量下降,鸡粪和牛粪的TN含量缓慢上升.堆肥过程中4种粪便对水堇种子的植物毒性均降低,且RGI和GI升幅由高到低为：牛粪 > 羊粪 > 鸡粪 > 猪粪.相关分析表明,堆肥过程中羊粪的TP、Cu、Zn,牛粪的Zn、TK、TP、NO₃^--N,鸡粪的NO₃^--N、TN、Cu,猪粪的NO₃^--N、TP、Zn、TK与RGI呈显著正相关（p<0.01）;而羊粪的Cu、TP、TK,牛粪的Zn、TK、TP,鸡粪的Cu、TN、NO₃^--N、TK,猪粪的TP、Zn、NO₃^--N与GI呈显著正相关（p<0.01）.由此表明,不同粪便堆肥的以上指标促进了植物的根伸长和种子发芽.但堆肥过程中羊粪的NH₄⁺-N、TN、DOC,牛粪的NH₄⁺-N、DOC、C/N、EC,鸡粪的C/N、EC、DOC,猪粪的NH₄⁺-N、DOC、EC与RGI呈显著负相关（p<0.01）;羊粪的NH₄⁺-N、TN、DOC,牛粪的NH₄⁺-N、DOC、C/N,鸡粪EC、DOC、C/N,猪粪的NH₄⁺-N、DOC、EC与GI呈显著负相关（p<0.01）.由此表明,不同粪便的以上指标显著抑制了植物的根伸长和种子发芽.多元回归分析说明,堆肥过程羊粪和牛粪的NH₄⁺-N,鸡粪的NO₃^--N、Cu、C/N和EC,猪粪的NO₃^--N和TK对水堇种子根伸长具有显著的影响,而羊粪的NH₄⁺-N和TK,牛粪的DOC、pH和EC,鸡粪Cu、TN和NO₃^--N,猪粪的TK对水堇种子发芽具有显著的影响.以上对比研究结果可为不同畜禽粪便槽式堆肥处理和土地利用提供重要的理论依据和决策支持.     

Hygroscopic properties of sodium and potassium salts as related to saline mineral dusts and sea salt aerosols

Mineral dust, soil, and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere, and their hygroscopicity affects the hydrological cycle and global climate. We investigated the hygroscopic behaviors of six Na- and K-containing salts commonly found in those primary organic aerosols. Their hygroscopic growths as a function of relative humidity (RH) agree well with thermodynamic model prediction. Temperature dependence of deliquescence RH (DRH) values for five of those salts was also investigated, which are comparable to those in literature within 1%–2% RH, most showing negative dependence on temperature. Hygroscopic growth curves of real-world soil and sea salt samples were also measured. The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition. The substantial amounts of water-soluble ions, including Na⁺ and K⁺, in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH (>80%) conditions. For three less-hygroscopic dust samples, however, measurements showed higher water uptake ability than that predicted by the thermodynamic model. The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH. The results of this study provide a comprehensive characterization of the hygroscopicity of Na- and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.     

灾害地貌链及其临界过程初探

在灾害链定义的基础上提出了灾害地貌链的定义 (即由地貌灾害所构成的灾害链 ) ,基于不同的标准将其划分为不同的种类 ,运用苏姆的地貌临界理论对地貌灾害中的两种临界进行浅析 ,最后运用耗散结构理论来探讨灾害地貌链中的临界过程。     

大气细颗粒物与糖尿病

随着我国社会经济和城市化的快速发展,大气颗粒物是影响我国城市空气质量的首要污染物,大气细颗粒物污染已严重威胁我国居民健康。本文简要综述了PM2.5诱导的氧化应激和炎症反应在糖尿病的发生和发展中的分子作用机制。     

猫儿山自然保护区森林群落垂直格局与主导因素分析

陆地生态系统中海拔高度的变化会导致植物群落的垂直性分布,这是形成植物多样性的一个重要性原因。了解和分析不同区域植物群落的垂直性分布规律和生物多样性形成机制对保护森林生物多样性具有重要意义。本文通过对猫儿山自然保护区不同海拔高度森林植物群落和环境因子的调查,运用双向指示种分析（Two-way Indicator-Species Analysis）和典范对应分析（Canonical Correspondence Analysis）,对不同海拔高度的群落进行划分,对决定植物群落分布的主导环境因子进行分析,结果表明：（1）猫儿自然保护区森林群落可以分为7个群落类型,其代表树种分别是罗浮栲Castanopsis fabri、栲树Castanopsis fargeisii、银木荷Schima argentea、铁椎栲Castanopsis lamontii、南方铁杉Tsuga chinensis、长苞铁杉Tsuga longibracterata、马尾松Pinus massoniana;（2）在中亚热带,海拔对山地植物群落形成起决定性作用;（3）土壤是仅次于海拔的重要环境因子,其中土类和土层厚度对森林群落的影响较大。在中亚热带森林生态保护和恢复过程中,按照不同海拔高度的植物群落特征选择种植合适树种,按照当地土壤条件选择适当的生态保护和恢复措施能加快生态恢复的进程,提高生态保护的效益。     

Decision Support System for emergency scheduling of raw water supply systems with multiple sources

A hydraulic model-based emergency scheduling Decision Support System (DSS) is designed to eliminate the impact of sudden contamination incidents occurring upstream in raw water supply systems with multiple sources. The DSS consists of four functional modules, including water quality prediction, system safety assessment, emergency strategy inference and scheduling optimization. The work flow of the DSS is as follows. First, the water quality variations on specific cross-sections are calculated given the pollution information. Next, a comprehensive evaluation on the safety of the current system is conducted using the outputs in the first module. This will assist in the assessment of whether the system is in danger of failure, taking both the impact of pollution and system capacity into account. If there is a severe impact of contamination on the reliability of the system, a fuzzy logic based inference module is employed to generate reasonable strategies including technical measures. Otherwise, a Genetic Algorithm (GA)-based optimization model will be used to find the least-cost scheduling plan. The proposed DSS has been applied to a coastal city in South China during a saline tide period as validation. Through scenario analysis, it is demonstrated that this DSS tool is instrumental in emergency scheduling for the water company to quickly and effectively respond to sudden contamination incidents.     

油田企业清洁生产审核实例

油田企业在为国家提供丰富石油资源的同时也成为环境污染的大户。自推行清洁生产以来,我国油田企业在清洁生产审核过程、节能降耗、环境保护等方面取得了较好成绩。以某油田企业为例,根据清洁生产＂节能、降耗、减污、增效＂的思路,以企业能源、资源利用情况的分析为基础,提出和实施了多项清洁生产方案。通过注气闸门填料改进、洗车用水回收再利用、化验室增加回收罐回收污油等方案的实施,同比可节电：20.74×104kW.h/a、节气：52×104m3/a、节水：2.80×104m3/a、减少污油排放：1.50 t/a左右,实现了经济效益和环境效益的双赢。     

Migration of manganese and iron during the adsorption-regeneration cycles for arsenic removal

Fe-Mn binary oxide incorporated into porous diatomite (FMBO-diatomite) was prepared in situ and regenerated in a fixed-bed column for arsenite [As(III)] and arsenate [As(V)] removal. Four consecutive adsorption cycles were operated under the following conditions: Initial arsenic concentration of 0.1 mg·L^-1, empty bed contact time of 5 min, and pH 7.0. About 3000, 3300, 3800, and 4500 bed volumes of eligible effluent (arsenic concentration≤0.01 mg·L^-1) were obtained in four As(III) adsorption cycles; while about 2000, 2300, 2500, and 3100 bed volumes of eligible effluent were obtained in four As(V) adsorption cycles. The dissection results of FMBO-diatomite fixed-bed exhibited that small amounts of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III) removal process. Compared to the extremely low concentration of iron (<0.01 mg·L^-1), the fluctuation concentration of Mn²⁺ in effluent of the As(III) removal column was in a range of 0.01–0.08 mg·L^-1. The release of manganese suggested that manganese oxides played an important role in As(III) oxidation. Determined with the US EPA toxicity characteristic leaching procedure (TCLP), the leaching risk of As(III) on exhausted FMBO-diatomite was lower than that of As(V).     

Highly controlled nest homeostasis of honey bees helps deactivate phenolics in nectar

Honey bees have a highly developed nest homeostasis, for example, maintaining low CO₂ levels and stable nest temperatures at 35°C.We investigate the role of nest homeostasis in deactivating phenolic compounds present in the nectar of Aloe littoralis. We show that the phenolic content in nectar was reduced (from 0.65% to 0.49%) after nectar was incubated in a nest of Apis cerana, and that it was reduced still more (from 0.65% to 0.37%) if nectar was mixed with hypopharyngeal gland proteins (HGP) of worker bees before being placed inside a nest. HGP had little effect on samples outside a nest, indicating that nest conditions are necessary for HGP to deactivate phenolics in nectar. Consequently, the highly controlled nest homeostasis of honey bees facilitates direct deactivation of phenolics in nectar, and plays a role in the action of HGP as well.     

Modeling and verifying chlorine decay and chloroacetic acid formation in drinking water chlorination

This study presents a phenomenological model that can be used by the water professionals to quantify chlorine decay and disinfection byproduct (DBP) formation in water. The kinetic model was developed by introducing the concept of limiting chlorine demand and extending an established reactive species approach. The limiting chlorine demand, which quantifies chlorine reactive natural organic matter (NOM) on an equivalent basis, was mathematically defined by the relation between ultimate chlorine residue and initial chlorine dose. It was found experimentally that NOM in water has limiting chlorine demand that increases with chlorine dose once the ultimate residue is established. These results indicated that the complex NOM has a unique ability to adjust chemically to the change in redox condition caused by the free chlorine. It is attributed mainly to the redundant functional groups that persist in heterogeneous NOM molecules. The results also demonstrated that the effect of chlorine dose on the rate of chlorine decay can be quantitatively interpreted with the limiting chlorine demand. The kinetic model developed was validated for chlorine decay and chloroacetic acid formation in finished drinking water.