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.     

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).     

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.     

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     

嗜盐菌的特性与高盐废水生物处理的进展

论述了嗜盐菌的形态特征、营养构成、生理特性和嗜盐机理，以及利用其特性在含盐有机废水处理中的应用，综述了国内外生化处理高含盐量有机工业废水的实验研究成果、在实际废水工程中的应用及其发展方向。对嗜盐菌的培养与驯化有一定的参考价值，对含盐废水处理工程的设计与运行有指导意义。     

Visualisation of the complexity of EUSES

The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters (inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation, on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency. The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters), and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity to 961, and the maximal dimension is 21.     

地铁颗粒物特征分析及磁性过滤控制

通过SEM-EDX和XRD对采集来的地铁颗粒物（PM10和PM2.5）进行形貌和成分分析,研究结果表明：地铁颗粒物具有粒径大（可达10 μm）、形状不规则、表面具有明显的刮擦痕迹等特征,主要成分为Si、C、O和Fe;其中Fe主要以Fe3O4、Fe2O3等氧化物的形式存在。针对地铁颗粒物含铁磁的特性,采用磁性过滤控制方法对地铁颗粒物开展研究,构建的磁性过滤装置对该地铁颗粒物的捕获效果可达90%以上,在一定磁性强度范围内（0 ~ 0. 300 T）,滤网对颗粒物的捕获效果随着对其施加的磁性强度增加而提升,当施加的磁场强度为0. 300 T时,装置对地铁颗粒物的捕获效率接近100%,比相同条件下对飞灰的捕获效率高出10% ~ 15%,建议把磁过滤作为一种前处理装置用在含磁颗粒物处理上。     

Spectrophotometric Determination of Atmospheric Acidity by means of the Displacement of the Equilibrium of Acid-Base Indicators

A method is described for determining acidity by means of the spectrophotometric determination of the displacement of the equilibrium of açid-base indicators. The method is simple, sensitive and free of known interferences. There is no dependence on costly or sophisticated equipment and the results obtained are reliable and reproducible.     

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.     

Corrosive Effects of Mixtures of Pollutants

The corrosion films that form on metals and alloys during field exposure are generally chemical mixtures. It is clear that the formation of such films requires the presence of mixtures of atmospheric corrosive gases, or of a combination of corrosive gases and atmospheric aerosol particles. Thus, laboratory experiments designed to reproduce field effects must involve mixtures of corrosive constituents. In this paper we review the mixed corrodent experiments of ourselves and others, describe the synergistic effects of mixtures of pollutants on a variety of metals, and present the necessary ingredients for experiments designed to simulate the interactive effects of atmospheric corrosive constituents.     

乌江汇入对三峡水库局部水体中磷质量浓度的影响

乌江水体中总磷与三峡水库相关水域存在差异。通过对相关水体中磷质量浓度变化特征的分析,结果表明：2008年前乌江TP显著低于三峡水库相关水域,其汇入对后者主要表现为“稀释”作用,可使清溪场断面TP年均值最大降低约0.02 mg·L⁻¹;2009年后乌江TP急剧升高,其汇入后清溪场断面2009—2013年TP年均值最大升高约0.057 mg·L⁻¹;2014年后乌江汇入基本不会使清溪场断面TP年均值明显改变;1998—2006年乌江TDP与三峡水库相关水域相近,乌江汇入对清溪场断面TDP年均值基本无影响;之后乌江TDP快速上升,2007—2013年乌江汇入最大可使清溪场断面TDP年均值升高约0.061 mg·L⁻¹;2014年后乌江TDP大幅回落,其对水库影响降低,最大可使清溪场断面TDP年均值升高约0.008 mg·L⁻¹;乌江汇入对三峡水库局部水体磷质量浓度的影响在不同时段其程度、趋势均不一致;乌江干流水电建设导致的水文条件变化和乌江上游区域磷矿开发过程中含磷废水排放使得乌江水体中磷质量浓度发生改变,进而间接、持续对三峡水库局部水体中磷质量浓度产生影响。该研究结果可为三峡水库的水生态环境监管提供参考。     

阳宗海沉积物中重金属生物有效性评估

通过测定和分析阳宗海表层沉积物中酸可挥发性硫化物(AVS)和同步提取重金属(SEM)的含量和分布特征,采用SEM/AVS方法对阳宗海表层沉积物中重金属的生物有效性进行评估;同时,采用生物有效阈值法评估了单一重金属的生物有效性。研究得出以下结论:阳宗海表层沉积物中AVS含量为15.09~149.74 μmol/g,平均值为49.42 μmol/g,从南向北呈递减趋势;AVS在南部和中部均与湖泊水深呈现正相关关系;∑SEM(包括Cu、Cr、Pb、Zn、Mn、As、Cd)含量分布波动较小,其范围为4.84~16.10 μmol/g,平均值为10.28 μmol/g,其分布规律为北部大于南部;阳宗海各采样点SEM/AVS<1,说明阳宗海表层沉积物中重金属不会对生物产生不良影响;从单一重金属来看,Pb可能经常产生生物毒性,Cu有可能产生生物毒性,其他金属除部分点可能产生生物毒性外,整体上几乎不会产生生物毒性。     

Evaluation of the presence of drugs of abuse in tap waters

A total of seventy samples of drinking water were tested for non-controlled and illicit drugs. Of these, 43 were from Spanish cities, 15 from seven other European countries, three from Japan and nine from seven different Latin American countries. The most frequently detected compounds were caffeine, nicotine, cotinine, cocaine and its metabolite benzoylecgonine, methadone and its metabolite EDDP. The mean concentrations of non-controlled drugs were: for caffeine 50 and 19 ng L⁻¹, in Spanish and worldwide drinking water respectively and for nicotine 13 and 19 ng L⁻¹. Illicit drugs were sparsely present and usually at ultratrace level (<1 ng L⁻¹). For example, cocaine has mean values of 0.4 (Spain) and 0.3 ng L⁻¹ (worldwide), whereas for benzoylecgonine, these mean values were 0.4 and 1.8 ng L⁻¹, respectively. Higher concentrations of benzoylecgonine were found in Latin American samples (up to 15 ng L⁻¹). No opiates were identified in any sample but the presence of methadone and EDDP was frequently detected. Total mean values for EDDP were 0.4 ng L⁻¹ (Spain) and 0.3 ng L⁻¹ (worldwide). Very few samples tested positive for amphetamines, in line with the reactivity of chlorine with these compounds. No cannabinoids, LSD, ketamine, fentanyl and PCP were detected.     

Accumulation of silver in the liver of three species of pinnipeds

Silver in the three species of pinnipeds [northern fur seal (Callorhinus ursinus), Steller sea lion (Eumetopias jubatus), and harbor seal (Phoca vitulina)] caught in the North Pacific Ocean were analyzed using inductively coupled plasma-mass spectrometry, in order to understand accumulation and distribution of silver in pinnipeds. In northern fur seals, relatively high concentrations of silver were observed in the liver and body hair. Some 70% of the silver burden was concentrated in the liver. Hepatic silver concentrations were significantly correlated to age in northern fur seals (r = 0.766, P < 0.001, n = 49) and Steller sea lions (r = 0.496, P < 0.01, n = 28). Levels of silver concentrations per wet weight (microgram g-1) in the three pinnipeds ranged from 0.04 to 0.55 for northern fur seals, from 0.1 to 1.04 for Steller sea lions and from 0.03 to 0.83 for harbor seals. Silver concentrations in liver for all pinnipeds were significantly correlated with mercury, and selenium (P < 0.001). Molar ratios between silver to selenium approximated 1:180 in northern fur seals, 1:120 in Steller sea lions, and 1:60 in harbor seals. The silver-mercury molar ratios were approximately 1:170 in northern fur seals, and 1:80 both in the other species. Increase in silver accumulation in the liver was caused by the retention in nuclei and mitochondria fraction together with mercury and selenium in the cells of northern fur seals.     

淋滤原液性质对生活垃圾淋滤的影响

利用淋滤反应器(BIOBUNK reactor)处理经破碎后的生活垃圾,对淋滤液COD、pH、VFA、TS、VS/TS等参数与淋滤出渣含固率、VS/TS、固相减量率进行实验研究。实验结果表明,将厌氧出水与酸化的餐厨浆液的混合液作为淋滤原液较直接将厌氧出水作为淋滤原液,对淋滤处理效果更显著。淋滤液COD提高14%,VFA提高13%,TS、VS/TS提高1%、3.5%,而pH值降低0.6。淋滤固渣减量率提高1.8%,VS减量率提高6.7%。淋滤出渣湿基低位热值(LHV)约为16 900 kJ/kg,远高于原垃圾的3 490 kJ/kg。出料热值高,可考虑做生物衍生燃料(biotechnology derived fuel,BDF)。     

Biodegradability of surfactants and inhibition of surfactants to biodegradation of other pollutants

Changes of BOD/TOD and DOC with time were obtained for solutions of 9 synthetic surfactants and 2 fatty acid salts under various conditions. The cationic surfactants, ABM and ABDM, were not biodegraded at all and inhibited the biodegradation of a synthetic sewage. LAS was not biodegraded at concentration of 30 mg/l and higher and inhibited the biodegradation of the sewage.     

微量金属对废水厌氧处理效果的影响

以葡萄酒蒸馏废水的厌氧生物处理为例,研究了Fe、Ni、Co、Mo、Cu、Zn对厌氧反应器的COD去除率、出水中挥发性有机酸含量、气体产量、气体成分、pH缓冲能力和碱度等的影响.对比了微量金属投加前后,厌氧反应器污泥中微量金属含量的变化.得出微量金属具有提高厌氧运行效果的作用,其中,Co的作用要更大一些.Ni、Co、Mo在附着态、悬浮态污泥中具有逐渐积累的特点;Fe、Cu、Zn在附着态污泥中是淋失的,而在悬浮态污泥中变化不大.     

A review of neurotoxicity of microcystins

Cyanobacterial blooms-produced microcystins are secondary metabolites which can accumulate in the food chain and contaminate water, thus posing a potential threat to the health of aquatic animals and even humans. Microcystin toxicity affects not only the liver but also the other organs, i.e., the brain. The serious neurotoxicity effects caused by microcystins then lead to various symptoms. This review focuses on the neurotoxicity of microcystins. Microcystins can cross blood-brain barrier with the transport of Oatps/OATPs, causing neurostructural, functional, and behavioral changes. In this review, potential uptake mechanisms and neurotoxicity mechanisms are summarized, including neurotransmissions, neurochannels, signal transduction, oxidative stress, and cytoskeleton disruption. However, further researches are needed for detailed studies on signaling pathways and the downstream pathways of neurotoxicity of microcystins.     

Geochemical evidences of the anthropogenic alteration of trace metal composition of the sediments of Chiricahueto marsh (SE Gulf of California)

Seven sediment cores (60-80 cm) were collected at Chiricahueto marsh, a salt marsh influenced by agrochemical, domestic and industrial effluents. The concentrations of Ag, Al, Cd, Co, Cu, Fe, Li, Mn, Pb, V and Zn were studied in the solid phase at each 1-cm section. The profiles of Ag, Cd, Cu, Mn, Ni, Pb and Zn showed a slight recent pollution in the site with enrichment and anthropogenic factors higher than unity; and correlation analysis indicated a direct association with organic carbon. Al, Co, Cr, Fe, Li, and V concentration profiles displayed a negative correlation with organic C and positive with mud content and no consistent enrichment at surface. Based on the principal component analysis and correlation analysis, two principal groups of metals were identified. The first group includes Al, Co, Cr, Fe and Li, that are derived predominantly from the weathering of parent materials in the local bedrock; and the second group include most of the metals, which were relatively enriched at surficial sediments, that are produced mainly by anthropogenic activities such as agriculture (Cd, Cu and Zn), sewage effluents (Ag, Cd, Cu, Ni, Pb and Zn) and in lesser extent atmospheric deposition (Cd and Pb).     

喷嘴数量对文丘里除尘器性能影响的模拟

选用欧拉-欧拉多相流模型和RNG k-ε湍流模型对文丘里除尘器流动特性进行数值模拟,首先对2个喷嘴时不同液体速度下的压力降和喉管液体分布情况进行模拟,并与实验值进行了比较,得到了较好的一致性;然后比较了2个喷嘴和4个喷嘴的情况下不同液体速度时文丘里除尘器的压力降和液体分布情况。模拟结果表明：欧拉-欧拉多相流模型可准确地模拟文丘里除尘器内部流场;喷嘴数量对文丘里除尘器内部的压力降和液体分布有较大影响,当相对射流深度为0.2,喉管气速为64 m·s-1,喷嘴数量由2增加为4时,压力降增加了17.17%,在喷嘴数目为4,喉管气速为74 m·s-1,液体速度为12.5 m·s-1时可使液体在文丘里除尘器内部得到较均匀的分布。