Antioxidant Activity and Total Phenolics of Propolis from the Basque Country (Northeastern Spain)

The purpose of this study was to evaluate the antioxidant activity (AA) of 19 propolis extracts prepared in different solvent (ethanol and propylene glycol). It was observed that all the samples tested had AA, although results varied considerably between extracts, i.e. 420–1,430 μmol Trolox/g (ABTS), 108–291 mg ascorbic acid/g (DPPH), and 1,573–4,669 μmol iron⁺⁺ sulfate/g (FRAP). The ethanol may enhance the potency of the AA, and the correlation coefficient between total phenolic content (TPC) (200–340 mg/g propolis extracts) and AA was statistically significant. Total flavonoids ranged from 72 to 161 mg/g propolis extracts. The results indicate that TPC and flavonoids contributed to AA.     

Balanced pasture fertilization in the Basque Country: I. Phosphorus and potassium budgets on dairy farms

Dairy farming is the main agricultural activity of the Basque Country. A dairy farm is characterized as a system with soils and crops, forage, cattle and manure as main components, and in such a system, nutrient cycling is very important to maintain soil fertility and optimize forage production. To quantify nutrient transfers in the cycle, a simple system was developed and has been applied to seventeen farms to examine its ability to achieve a balanced P and K fertilization. These farms have provided data on inputs (fertilizer, feeds, concentrates), pasture and manure management, and outputs (milk production), and soil samples have been taken from farm pastures. Phosphorus and K in excreta and uneaten pasture is used with a relatively high efficiency as suggested by the relatively high efficiency of P and K utilization by the pasture that usually ranges from 70 to 90%. Concentrate feeding (3000 kg cow^–1 yr^–1) represents one of the main P and K inputs in Basque Country dairy farms, averaging 26 and 66 kg ha^–1, respectively. Besides, release of K in the soil through slow liberation from non-exchangeable sites was estimated as 30 kg ha^–1. Thus, a high efficiency in excreta recycling would diminish substantially P and K mineral fertilizer needs. Farm nutrient budgets appear to be a convenient tool for determining nutrient shortages and surpluses at farm level, and thus they are considered as a first step to support a better management of maintenance fertilization of permanent pastures.     

Estimation of the Monthly Average Ratios of Organic Mass to Organic Carbon for Fine Particulate Matter at an Urban Site

Two independent methods are used to estimate the seasonality of the ratio of fine particulate organic matter (OM) to fine particulate organic carbon (OC) for atmospheric particulate matter collected at the St. Louis—Midwest Supersite. The first method assumes that all of the fine particulate matter mass that cannot be attributed to sulfate ion, nitrate ion, ammonium ion, elemental carbon and metal oxides is organic matter. Using this method, 98 daily samples were used to estimate the annual average fine particulate matter OM/OC ratio to be 1.81 ± 0.07 with a summer average of 1.95 ± 0.17 and a winter average of 1.77 ± 0.13. The second approach to estimating fine particle OM/OC employed OC source apportionment results and estimates of source specific OM/OC, including primary sources and secondary organic aerosol. The OM/OC estimate that was based on 98 daily source apportionment calculations over a two year period yielded an annual average ratio of 1.96 ± 0.03. Methods used in the study yielded a relatively stable annual average estimate of the OM/OC ratio for fine particulate matter in the St. Louis area. The source apportionment results indicate that the similar OM/OC ratio for St. Louis in the summer and winter results from an increased relative contribution of secondary organic aerosol in the summer months that is balanced by the higher woodsmoke in the winter. Although the estimated OM/OC ratios that were determined for St. Louis cannot be directly applied to other locations, the methodologies used to estimate OM/OC can be broadly applied given the necessary data for these calculations.     

合肥市城区土壤 pH 值分布研究

为了解合肥市城区土壤pH值分布特征,以合肥市区主城区以内52个样点为基础,测定其pH值并绘制等值线图,结果显示, pH值大致为呈环状变化,从市中心向周围, pH值呈现由高变低,再由低变高的趋势。结合合肥市历史土壤普查资料分析,合肥市土壤有碱化趋势,并提出土壤碱化的建议。     

北京市城乡结合部大气可吸入颗粒物中正构烷烃的分析

分不同季节采集分析北京市城乡结合部的大气可吸入颗粒物。用气相色谱-质谱技术分析了北京市城乡结合部大气可吸入颗粒物中饱和烃组分,检测出C11～C37的正构烷烃及其它烃类化合物。正构烷烃分布主要可分为3种类型:前峰型、后峰型、单峰型。利用地球化学的相关参数,同时结合正构烷烃的分布特征,对正构烷烃的污染来源进行分析。前峰型,主要来源于汽车尾气和化石燃料燃烧。后峰型,主要来源于植物蜡。单峰型,既有植物蜡的输入,也有尾气和化石燃料燃烧的输入。对正构烷烃在不同季节大气可吸入颗粒物中分布情况的比较,表明正构烷烃分布随季节有较明显的变化。     

城市住宅小区再生水的利用分析

城市住宅小区再生水利用是水污染防治和节水的重要途径。本文对城市住宅小区再生水利用特点、工艺技术、利用途径和方式、存在问题等进行了初步探讨,就城市住宅小区再生水利用在技术使用、运营管理等方面的问题提出相应建议。     

上海城区近地面臭氧污染研究

利用上海城区空气自动监测站2014年1月1日至2018年12月31日的连续观测数据,分析了臭氧污染物的变化特征、影响因素。结果表明:臭氧已成为影响上海城区空气质量的主要污染物,夏季臭氧日均浓度高于其余季节,臭氧日内浓度变化呈单峰型,与前体污染物氮氧化物呈负相关性。臭氧的生成与气象条件密切相关,温度越高,臭氧浓度越高。相对湿度在50%～60%时臭氧浓度出现峰值,通过后向轨迹分析,上海南面大气输送对监测点臭氧污染贡献最大。     

恩施城区典型区域水体中磺胺类药物的检测评价

采用紫外分光光度法研究了恩施城区典型区域(医院、污水处理厂、水产养殖厂)水体中的磺胺类药物(主要为磺胺嘧啶和磺胺甲唑)残留含量。结果表明,这几个典型区域水体中均有磺胺类药物检出,所检出的磺胺甲唑的浓度高于磺胺嘧啶,某污水处理厂的磺胺类药物浓度最高,检出浓度可达微克级。     

上海城市排水干线连通策略

长距离输送的干线总管相对独立、互不联通,存在应对突发事件能力弱,无法停运检修;输送能力不均,无法统一调度等问题。上海目前已经形成了污水"就地分散收集、长距离外排输送和集中处理排江"的模式以及石洞口、竹园和白龙港三大排水片区的格局。然而,上海20世纪建造的枝状排水管道系统与新时代水环境治理的目标、城市精细化管理的要求有较大差距。本文邀请上海市政工程设计研究总院集团有限公司张欣总工介绍上海中心城区污水干线总管的互联互通方案,为其他城市排水系统格局的改造提升提供有益借鉴。     

Influence of Sampling Artefacts on Measured PM,OC, and EC Levels in Carbonaceous Aerosols in an Urban Area

The registration efficiency of the TSI model 3025 ultra-fine condensation particle counter for Ag and NaCl particles of between 2 and 20 nm in diameter was determined. Taking into account the different shapes of the input aerosol size distributions entering the differential mobility analyzer (DMA) and the transfer function of the DMA, the counting efficiencies of condensation nucleus counters (CNC) for monodisperse Ag and NaCl particles were estimated. In addition, the dependence of the CNC registration efficiency on the particle concentration was investigated.     

城区河涌水体污染分析及治理技术

自从改革开放以来,我国的各行各业均取得了突破性的进展,尤其是在工业领域,为了能够迎合发展的需要,在生产方面加大了投入,与此同时对城区河涌的水体产生了污染,为河涌的污水治理工作带来了一定的难度。目前,城区河涌水体中,关于水源的黑臭问题仍然存在,河涌的水体遭遇重大的污染。主要针对城区河涌水体污染目前存在的问题、从提高水体的质量、保护环境的角度出发,对河涌水体的污染源头展开研究,并提出一些治理方面的建议,希望能够对目前的水体污染程度起到控制的作用。     

Scavenging Kinetics in the Photochemistry of Some Ions in Aqueous Solution

Geminate recombination has been previously suggested in the photochemistry of several ions in solution, namely, the halides, phenolate ferrocyanide and thiocyanate. It is demonstrated that in the concentration range studied, the observed dependence of the quantum yield on scavenger concentrations is due to homogeneous competition between the scavenger and a product or rational intermediates, rather than to cage scavenging competing with geminate recombination.     

对老城区排水管网改造问题的探讨

城市排水系统是水资源利用、水污染控制和生态环境保护中的重要环节。文章指出对老城区排水管网进行改造,是城市发展过程中不可回避的问题。重点介绍了截流倍数、截流井、截流量、防倒灌等几个关键问题的设计原则及应注意的事项。并针对老城区排水管网改造中存在的问题提出相应的对策与建议。     

Revealing the Origin of Polycyclic Aromatic Hydrocarbons in an Urban Snowpack

Polyciclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban atmosphere. Several PAHs are known carcinogens or are the precursors to carcinogenic daughter compounds. Understanding the contributions of various PAH emission sources is critical to appropriately managing PAH levels in the environment. The sources of PAHs to urban snowpack in Shelekhov city, Eastern Siberia, characterized by extremely high levels of PAH accumulation in snow were determined by using end-member mixing approach. The best potential to distinguish PAH emission sources is exhibited by ratios of PAH pairs of the principal mass 228, 252, and 276. The ratios of PAH pairs were used as tracers of end-member PAH sources. The contributions of sources were calculated using systems of linear equations. The results obtained using ratios of PAH pairs were compared with those obtained using molecular diagnostic ratios. It was shown that the results obtained using diagnostic ratios as tracers are less reliable than the results obtained using the ratios of the sums of PAHs.     

Aerosol Development and Interaction in an Urban Plume

Wintertime measurements of atmospheric aerosol over the size range 3-500 nm made approximately 30 m above street level in central Manchester are reported. These are compared with measurements of trace gases. It is found that secondary accumulation mode particles follow closely the values of NO_x in the atmosphere and are closely related to vehicle activity, reaching a maximum at about 9 am. New particle formation close to the observation point is closely related to SO₂ concentrations, predominately during daylight hours, and is a maximum around mid-day but persists after dark. The concentrations of fine and Aitken mode particles were much higher than in nearby rural areas, but the concentration of particles in the size range 200-500 nm were similar at the urban and rural sites. In addition, measurements of ammonia, a gas often important in nucleation kinetics, revealed concentrations up to 17 ppb in Manchester.     

Effect of an Ionic Air Cleaner on Indoor/Outdoor Particle Ratios in a Residential Environment

We tested a leading commercially available ionic air cleaner in a typical residential apartment to study the effect of the device on indoor/outdoor airborne particle number and mass concentration ratios. In addition, we also determined the indoor ozone and ion concentration levels. When measured during normal daily activity, the average indoor/outdoor mass concentration ratio was reduced from 1.03 to 0.73 and the number concentration ratios underwent reductions for most of the particle size fractions. However, due to a substantial inter-and intra-measurement variation in particle ratios, the observed average reductions were not statistically significant. When measurements were performed in a still room, the indoor/outdoor particle mass concentration ratio decreased from 0.9–1.4 to 0.3–0.4 in eight hours when the air cleaner was operating. Ambient ozone concentrations measured in the middle of the apartment were between 13–19 ppb during normal daily activity and the ozone levels increased to 77 ppb when measured in front of the ionic cleaner during still conditions. We also found that that there was a limited vertical diffusion of ions. The highest ion concentrations were measured at a 0.5 m height from the floor and decreased substantially with increasing measurement height. This finding may have implications for effective particle removal from a person's breathing zone. Overall, we found that the tested brand of commercially available ionic air cleaners may have the capability to remove some airborne particulate matter in actual residential settings, but its cleaning effect is reduced under normal daily activity.     

NMR for the Determination off Ligand-Metal Ratios in Solvent Extraction

Abstract

In addition to the more conventional methods used in hydrometallurgy to determine the stoichiometry of ligand-metal species formed in solvent extraction, a few research efforts have been done to establish some spectroscopic techniques which can provide that information “in situ.” In this work, nuclear magnetic resonance is used to confirm the Cyanex 471X-silver ratio when the metal is extracted from a concentrated chloride medium on the basis of the “coordination shift” detected in some nucleus of the organic ligand upon complexation. The same approach has also been applied successfully to estimation of the composition of triphenylphosphine-silver chloride species synthesized in one phase.     

基于数值模拟的嘉兴城区河网水文特征

基于MIKE 11河网水动力模型,利用2010年—2019年实测气象水文资料,分析了嘉兴城区大包围圈内外主要河流的入流和出流特征.结果显示:嘉兴城区主要来流河道是苏州塘和杭州塘,出流河道主要为长纤塘、嘉善塘和平湖塘;平均来流量为88.2 m3/s,出流量为93.3 m3/s;年均和月均来流量变化较大,最枯月的平均来流量...