表面活性剂强化球形节杆菌修复DDTs污染农田土壤的现场实验

通过田间实验,研究了不同浓度的表面活性剂(SDBS-TW80和RL)对球形节杆菌Arthrobacter globiformis DC-1降解设施农业土壤中DDTs效果的影响。结果表明,SDBS-TW80和RL均能不同程度地促进球形节杆菌降解农田土壤中DDTs。当SDBS-TW80和RL浓度分别为200和5 mg·kg-1土时,DDTs的降解率达到最高,均为64%左右。DDTs组分分析表明:SDBS-TW80和RL对p,p'-DDE、p,p'-DDT、p,p'-DDD和o,p'-DDT 4种组分均有不同程度的降解,其中毒性最强的p,p'-DDE降解效果最好,最高达75%左右。实验结果证实了利用表面活性剂强化球形节杆菌现场修复DDTs污染土壤的可能性。考虑到修复效率和成本,实际应用中优先选择SDBS-TW80的组合。     

不同水分条件下活性污泥对土壤中DOM产生及DDT降解的影响

采用盆钵实验,通过控制淹水、田间最大持水量和60%相对含水量3种水分条件系统研究施用活性污泥(AS)对不同质地土壤中DOM的产生消长规律及DDT降解的影响,旨在为农药污染土壤修复及农产品清洁生产提供理论依据。结果表明:1)不同水分条件下AS均能提高土壤中DOM的含量,且随添加比例增加而增加;2)不同水分条件下AS均能促进土壤中p,p'-DDT降解,淹水条件下添加1%~3%的AS使粘土、壤土和砂土中p,p'-DDT的降解率分别提高4.0%~45.0%、2.7%~48.9%和2.2%~35.4%;最大持水量条件下粘土、壤土和砂土中p,p'-DDT的降解率分别提高2.9%~40.9%、1.9%~46.9%和2.1%~34.3%;60%相对含水量条件下粘土、壤土和砂土中p,p'-DDT的降解率分别提高3.0%~40.9%、2.1%~45.0%和1.7%~31.6%;3)不同水分条件下,不同质地土壤中添加AS后DOC含量与p,p'-DDT含量呈显著正相关。上述结果表明不同水分条件下AS对p,p'-DDT降解的促进效果表现为淹水条件最大持水量60%相对含水量,p,p'-DDT在不同质地土壤中的降解速度表现为壤土粘土砂土。     

4种表面活性剂及其混合物对p,p'-DDT污染土壤洗脱效果

为了研究表面活性剂对p,p'-DDT污染土壤的淋洗效果,选取了4种阴、非离子表面活性剂,对人工p,p'-DDT污染土壤进行单一和复配洗脱实验。结果表明,对于人工p,p'-DDT污染土壤,阴离子表面活性剂洗脱效果优于非离子表面活性剂,其中阴离子表面活性剂十二烷基硫酸钠(SDS)和鼠李糖脂(RL)的洗脱效果较好,添加量为15 000 mg·L~(-1)时洗脱率分别达到44.5%和36.5%,均优于非离子表面活性剂吐温80(TW80)(30.4%)和曲拉通100(TR100)(20.3%);研究还表明非离子表面活性剂在添加量达到10 000 mg·L~(-1)后,继续增加表面活性剂浓度,洗脱效果提升不明显。混合表面活性剂体系中,总添加量为10 000 mg·L~(-1)时,SDS-TW80混合体系对p,p'-DDT的洗脱率为42%,高于SDS-TR100(34.9%)、RLTW80(33.4%)和RL-TR100(37.4%),表面活性剂混合体系对于p,p'-DDT的淋洗有明显的协同作用。     

(汍)汊湖水体和表层沉积物中有机氯农药分布特征

用GC/ECD内标法定量测定了(汍)汉湖水体和表层沉积物中的有机氯农药(OCPs).(汍)汊湖水样和表层沉积物中20种OCPs均有检出.表层沉积物上层中(0～2 cm)的OCPs明显高于下层(2～10 cm),这是(汍)汉湖具有稳定的水动力条件所致.氯丹在表层沉积物中浓度最高,与该化合物在环境中的强稳定性以及在该地区的大量使用有关.表层沉积物样品DCHsO2上层OCPs中o,p'-DDT主要成分,表明近期可能有新的DDTs,特别是含大量o,p'-DDT的三氯杀螨醇的使用.DDD/DDE则显示表层沉积物上层DDTs的降解主要处在厌氧条件下,而下层处在好氧条件下.     

土壤中六六六和滴滴涕的堆肥生物修复研究

采用堆肥生物修复法对土壤中六六六(HCH)和滴滴涕(DDT)的降解效果进行了研究.试验结果表明,六六六和滴滴涕的降解先后经历了快速降解阶段和缓慢降解阶段;堆肥第21天后,六六六和滴滴涕降解率均达60%以上;γ-HCH降解效果最好,其次为β-HCH,α-HCH和δ-HCH的降解效果差别较大;p,p'-DDE的降解效果要好于p,p'-DDD,初始质量浓度为0.03 mg/kg的p,p'-DDT未得到降解;微生物对六六六和滴滴涕的降解作用均较明显.     

冀中典型农业区农作物中有机氯农药的生物富集特征与健康风险评价

分析了冀中典型农业区土壤-农作物体系中有机氯农药(OCPs)残留与生物富集特征,探讨了该地区所产农作物的可食部分对人体健康产生的潜在风险。结果表明:11种OCPs以滴滴涕(DDTs)和六六六(HCHs)为主要残留物。土壤中DDTs和HCHs残留量总计达36.52~73.45ng/g,在各自的异构体中p,p’-DDT和γ-HCH所占比例最高,表明OCPs污染主要为近期输入所致。玉米和小麦各器官中,OCPs均在籽粒中最高,分别残留20.66~33.33、19.14~34.57ng/g。小麦和玉米对HCHs的富集能力均强于DDTs。研究显示,该地区玉米与小麦籽粒中OCPs含量虽未超过《农产品安全质量无公害蔬菜安全要求》(GB 18406.1—2001)和《食品安全国家标准食品中农药最大残留限量》(GB 2763—2012),但OCPs致癌总风险相对较高,玉米和小麦中均超过了1×10-6,小麦中OCPs的非致癌总风险和致癌总风险均大于玉米,因此该地区应该优先关注OCPs对小麦所造成的粮食安全问题。     

舟山近岸海域贝类中有机氯农药残留水平及人体健康风险评估

于2012年的7月在舟山群岛新区的海域采集贝类样本,测定了其中的有机氯农药残留量,并进行了人体健康风险评估和安全食用量推算。结果表明,采集的5种贝类样本中,六六六(BHCs)的各组分均未被检出,而滴滴涕(DDTs)在各种样本中均有检出,其中僧帽牡蛎和部分縊蛏样本中DDTs总量超过《海洋生物质量标准》(GB 18421—2001)一类标准(10μg/kg);健康风险评估结果显示,贝类样本中α-BHC、β-BHC、γ-BHC、p,p’-滴滴伊(p,p’-DDE)、p,p’-滴滴滴(p,p’-DDD)、p,p’-DDT的总致癌风险指数均低于10-4,致癌风险均在可接受的安全范围,α-BHC、β-BHC、γ-BHC、p,p’-DDE的总接触风险指数均小于1,接触风险指数未超过危害剂量参考值,人体食用舟山近岸海域的贝类是安全的;按可接受的致癌风险指数进行评估,人体的贝类安全消费量为9.8~138.0g/(kg·d)(按体重计,下同),而按可接受的接触风险指数进行评估,人体的贝类安全消费量在24.6~235.0g/(kg·d)。     

4种碱基添加剂对1,2,4-三氯苯污染土壤热脱附效果的影响

含氯有机物是土壤中常见的污染物质,对人体危害大,采用热脱附修复技术去除。通过改变加热温度、加热时间及添加4种碱性物质(NaHCO3、NaOH、Ca(OH)2、CaCO3)等条件获取TCB的去除效率及污染土壤理化性质变化情况。实验结果表明,热脱附能有效去除土壤中TCB,当温度为350℃加热30 min时,污染土壤中TCB去除率为83.27%;碱性物质的添加能有效强化热脱附过程,添加1%的NaHCO3、NaOH、Ca(OH)2和CaCO3后,TCB去除率分别提高了28.28、26.13、20.28、18.19%。碱性物质的添加促进了TCB的脱氯和降解,相比于无碱性物质热脱附,添加1%NaHCO3和NaOH后尾气中DCBz增加了5.4 ug·L-1和3.65 ug·L-1。热脱附后土壤有机碳、有效磷质量分数和阳离子交换量减少,电导率增大;碱基协同热脱附前后土壤的总有机碳质量分数变化不大,土壤中有效磷质量分数和阳离子交换量明显增大,脱附条件为250℃、30 min以及1%的Ca(OH)2时,脱附前后有效磷由57.5 mg·kg-1增大至80.2 mg·kg-1,阳离子交换量由19.72 cmo...     

不同洗脱剂对有机氯农药污染场地土壤修复效果比较

为了筛选出能有效修复有机氯农药污染土壤的洗脱剂,选取了16种洗脱剂对2种复合有机氯农药(六六六(HCHs)和滴滴涕(DDTs)、氯丹和灭蚁灵)污染场地土壤进行超声洗脱修复。结果表明,对于HCHs和DDTs复合污染土壤,乙酸乙酯和丙酮对HCHs的洗脱率最高,分别为87.6%和87%,其余有机溶剂对其洗脱率也在70%以上。乙酸乙酯和丙酮对于DDT仍为最优,分别为86.9%与78.4%,其余有机试剂对DDT的洗脱率在60%以上。相对于有机溶剂,表面活性剂对HCHs和DDTs复合污染土壤的洗脱效果不好,总洗脱率均低于4%。同样,对于氯丹和灭蚁灵复合污染土壤,有机溶剂的洗脱效果也明显优于表面活性剂。有机溶剂对灭蚁灵的洗脱率,除了正丙醇较低(63.5%)外,其余均在80%左右。对氯丹的洗脱率,除石油醚(59.6%)、正己烷(49.3%)和正丙醇(42%),其余均在70%以上。相同摩尔浓度的表面活性剂中,吐温80对氯丹的洗脱率为54%,环糊精为20%,鼠李糖脂和曲拉通100为13%左右,其余则小于5%,吐温80对灭蚁灵的洗脱率为29.6%,曲拉通100的为12.4%,鼠李糖脂为5.7%,其余则更低。因此,高效低毒的有机试剂,如乙酸乙酯、丙酮和乙醇等可作为有机氯农药污染土壤修复的首选。     

热解吸对土壤中POPs农药的去除及土壤理化性质的影响

为探索土壤热解吸修复技术对POPs污染土壤的修复效果及修复后土壤可耕作性,选择北京某农药厂旧址的POPs农药污染土壤,研究了不同温度下热解吸处理后土壤中滴滴涕(DDTs)和六六六(HCHs)各组分的去除率以及土壤理化性质的变化。结果表明,热解吸修复技术可有效去除土壤中POPs农药,其中,p,p’-DDE与α-HCH组分去除率受热解吸温度的影响比其他组分更为明显。∑HCH与∑DDT在310℃、340℃时分别达到97%、99%的去除率,且此时土壤中的污染物含量低于我国《展览会用地土壤环境质量评价标准》,此后去除率受温度的影响不明显。热解吸温度对修复后土壤的理化性质有一定的影响,不同温度影响的程度各不相同,其中,有机质含量与全氮含量分别由0.78%、0.0352%降至0.14%、0.0107%;pH波动幅度较小,由7.80变至8.25;阳离子交换量变化存在波动,但呈整体下降趋势,由7.87 mg/kg降至5.00mg/kg;土壤中速效磷显著增加,由7.59 mg/kg升至21.8 mg/kg。而在最优温度条件下,土壤理化性质受热解吸温度的影响较小。由此可以说明,热解吸技术可以用于POPs污染土壤的修复,选择适当的热解吸温度对土壤的可耕作性影响有限,因而是一种潜在的绿色修复技术。     

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).     

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。     

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。     

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.     

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     

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.     

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.