北京南海子湖藻垫在春夏交替季节水华过程中的作用

藻垫对湖泊水体水华发生是否有影响及影响机制是目前水体富营养化研究的一个前沿课题。本文以北京南海子湖为例,研究湖底藻垫对水体水华爆发的影响。通过对干燥藻垫和水华过程新产生的藻垫进行培养对比实验,揭示不同时期形成的藻垫对水体藻生物量的影响即水华的影响。结果表明,不同干燥时间的藻垫均对水体藻生物量有影响,进入藻生长平台期,水体叶绿素a浓度范围为15~20μg/L,而灭菌后的藻垫培养水体中叶绿素a浓度低于10μg/L;水华爆发后新生成的藻垫对水体藻生物量也有贡献,培养水体叶绿素a范围也达到15-20μg/L;干燥时间对藻垫培养后水体浮游植物生物量的影响较弱。     

鲢鳙放养水平对淀山湖浮游植物群落影响的围隔实验

在淀山湖进行放养不同密度鲢、鳙的围隔实验（密度水平梯度设置为0、40、80和120 g/m3）,探索鲢、鳙的现场控藻效果。结果表明,实验后期（8—9月）,鲢、鳙放养密度为80 g/m3和120 g/m3的围隔对叶绿素a的去除效果显著（P〈0.05）;且放养密度为80 g/m3的围隔蓝藻比例降幅最明显。鲢、鳙对较大个体藻...     

洋河水库水华优势种演替的原因分析

针对鱼腥藻和微囊藻这2种洋河水库水华暴发常见优势藻,研究了其在不同温度及硝态氮浓度下的生长情况。结果表明,在温度15～25℃,硝态氮浓度0.05～10 mg/L的范围内,温度的升高、硝态氮浓度的增加,对鱼腥藻的生长影响不明显,却能够明显地促进微囊藻的增长。15℃或0.05 mg/L硝氮条件下,鱼腥藻的比增长速率高于微囊藻,而25℃或10 mg/L硝氮时,微囊藻的比增长速率分别达到了0.425 d-1和0.466 d-1,明显超过鱼腥藻。洋河水库逐年升高的硝态氮浓度以及夏秋季节比较适宜的温度促进了微囊藻的增长,可能是洋河水库水华优势种由螺旋鱼腥藻向微囊藻转变的重要因素。     

鲢鱼放养控制北京城市河湖水华试验研究

介绍了利用鲢鱼控制北京城市河湖水华的试验研究,通过不同放养密度(0、17、51和103 g/m3)的现场围隔试验,对鲢鱼放养对水体水质和浮游生物的影响进行了分析.研究结果表明,鲢鱼放养使有鱼围隔中浮游生物量极低,从而使浮游植物基本不受浮游动物影响,而直接受鱼类影响;同时,中等密度(51 g/m3)的鲢鱼放养使水华蓝藻和微小藻的生长均得到了有效抑制,使藻类生物量最低.     

以再生水为补水的景观水体水华爆发特征调查和药剂应急控藻效果评价

采用现场调查和实验室验证的方法,对以再生水为景观补水的水华优势藻进行了分析。2年的现场调查表明,再生水在条件适合时极易发生水华,且水华的优势藻以小球藻为主。在实验室针对小球藻和铜绿微囊藻进行了竞争生长实验研究,在再生水的氮磷浓度范围内小球藻生长快于铜绿微囊藻,这也验证了再生水作为景观水补水时小球藻是优势藻现场调查结论。针对水华爆发初期和水华爆发验证时2种条件,比较研究了4种以化学成分为主的抑藻药剂对以小球藻为水华特征藻的控藻效果。结果表明,这4种药剂对水华的控制均具有一定的效果,并且水华初期实施药剂抑藻,药剂投加少,且效果好。对4种药剂进行急性毒性实验,只有S2一种药剂在安全浓度时对水华爆发初期有抑藻效果。     

深水型水库水质因子与藻类群落垂向演替及水华爆发机制分析

将莆田市东圳水库垂向划分为表层、中层、和深层,研究其藻类群落的分布特征及其受环境因子影响的演变规律,进而明晰“水华”爆发机制。结果表明,水库中共检出浮游藻类7门39属,群落结构主要以蓝藻、绿藻、硅藻和隐藻为主,在不同季节沿水库垂向分布呈现显著差异性。表层和中层水体中优势藻类为绿藻门和蓝藻门,受水温、光照、DO和TN影响;深层水体优势藻类为硅藻和隐藻,主要受水温和TN影响。对水库中营养盐分析结果表明,东圳水库N/P平均值达到32.4,呈典型磷限制性特征,水库氮污染主要来自农业面源输入和内源释放。底泥中氮类物质易于在夏季分层期发生释放,并与DO结合发生形态转化后输入至上层水体,由此导致“水华”现象的发生。针对东圳水库水华防范与治理,需严格防控点源和农业面源污染,并建设水力扰动设施以及增设原位修复装置等措施,全方位防控水华现象的发生。本研究通过分析东圳水库藻类功能组时空演替,有助于确定东圳水库藻类爆发机制,可为水库藻类治理、水环境生态保护提供参考。     

蓄水型备用水源地藻类生长趋势及控藻技术研究

为了探明以洪泽湖为原水的某蓄水型备用水源地藻类生长情况，探索原位控藻方法，进行了为期1年的藻类数量测定，并进行了遮光控藻实验和清浑混合控藻实验。结果表明，备用水源地优势藻类为硅藻门(Diatom)的针杆藻属(Synedra),持续全年；7—8月出现蓝藻门(Cyanobacteria)的微囊藻属(Microcystis)。藻细胞数量夏季多、冬季少，在7—8月达到峰值(2.09×10⁷个/L),1月达到谷值(9.23×10⁶个/L)。藻类在复合湿地区比进水口下降约4.8%,在深水净化区比进水口增加0.3%。藻类在0.5 m水深处最多，表面、3.0 m水深处藻类数量分别是0.5 m水深处的92.1%和89.9%。遮盖率为40%、60%、80%、100%的水体稳态控藻率分别为24.2%、41.4%、47.0%、61.1%,稳态高锰酸盐(I_Mn)削减率分别为24.8%、36.5%、41.6%、47.7%。建议采用太阳能发电板遮蔽水面控藻，遮盖率取60%。清浑混合体积比为6∶4、7∶3、8∶2、9∶1的水体稳态控藻率分别为33.2%...     

水华束丝藻与铜绿微囊藻净化水体氮磷及其脂质积累过程比较

选取水华束丝藻与铜绿微囊藻作为典型水华蓝藻,探索水华蓝藻净化水体及合成生物柴油的潜力.采用氮磷浓度为NH4-N 7.5 mg/L,PO43--P 1.0 mg/L的模拟污水,重点考察了在光照强度与温度不同的条件下2种微藻对氮磷的去除率,并利用尼罗红荧光染色法测定了微藻中的中性脂含量.结果表明,2种藻对PO43--P的去除率均较高,最高达到98％,对NH4+-N的去除率稍低,最高为52％.水华束丝藻及铜绿微囊藻均具有较强积累中性脂的能力,适宜的温度与光照条件有利于微藻对氮磷的去除及细胞中脂类的积累.2种藻均在光照强度为12 000 lx时中性脂含量更高.水华束丝藻在温度为18 ～22℃条件下,生长更优,氮磷净化效果较好,中性脂积累能力更强.而铜绿微囊藻在温度为22～ 26℃时表现更好.     

氮浓度对小环藻、大型溞和金鱼藻相互作用的影响研究

以浮游植物小环藻(Cyclotella sp.)、浮游动物大型溞(Daphnia magna)和大型沉水植物金鱼藻(Ceratophyllum demersum)为研究对象,建立水生微宇宙模型,在1.5mg/L磷、2 600lx光强和25℃条件下,研究不同氮质量浓度(0.5、2.0、4.0、8.0、16.0mg/L)对生物操纵效果的影响。结果表明,小环藻单独培养时,氮浓度越高,小环藻增长率越大;小环藻和大型溞共培养、小环藻和金鱼藻共培养且氮为0.5～2.0mg/L时,小环藻生长受到明显抑制,大型溞和金鱼藻均生长良好;3者共培养且氮为0.5～16.0mg/L时,小环藻的生长均得到有效控制。总体而言,控藻效果表现为:小环藻、大型溞和金鱼藻共培养小环藻和金鱼藻共培养金鱼藻种植水对小环藻的化感作用小环藻和大型溞共培养,大型溞和金鱼藻的联合作用比其单独的控藻效果好,随着氮浓度增加,控制效果逐渐减弱,氮小于2.0mg/L最好。氮为0.5～2.0mg/L时,水中TN去除率相对较高,氮为16.0mg/L时,水中TP去除率相对较高。     

环糊精及其衍生物对降低铅和菲的藻类毒性研究

研究了环糊精(CD)及其衍生物对重金属铅和有机物菲及其复合污染胁迫下斜生栅藻(Scenedesmus obliquus)的毒性影响。结果表明,天冬氨酸-β-CD(ACD)具有促进斜生栅藻生长的作用。在单一铅或菲胁迫下,低浓度时能促进斜生栅藻的生长作用,但当铅质量浓度≥0.10mg/L或菲质量浓度≥10μg/L时,斜生栅藻的生长都受到了不同程度的抑制。100 mg/L的ACD加入后,在相同浓度的铅或菲胁迫下,斜生栅藻抑制率明显降低。其中,铅对斜生栅藻96h的半数效应浓度(EC50)由0.96mg/L增加到了3.79mg/L,菲对斜生栅藻96h的EC50由40μg/L增加到了104μg/L,毒性明显降低。复合污染时,铅和菲对斜生栅藻的毒性表现出协同作用。不同CD(α-CD、β-CD和γ-CD)及其衍生物(ACD和羟丙基-β-CD)中,对降低斜生栅藻毒性效果最好的为ACD。     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.