Carbon Monoxide Concentration in a Street Canyon of Buenos Aires City (Argentina)

The analysis of three years of 8-h CO concentration values registered in a deep street canyon downtown shows high frequency of values that exceed WHO health protection guidelines. An inverse relationship between opposing percentiles of the distributions of CO concentrations and mean wind speed could be found. Data also showed a variation of mean CO values with prevailing wind direction. The averaged concentration value obtained when the sampler probe is on the leeward side is lower than the obtained when it is on the windward wall. A preliminary explanation of this feature may be related to the advection of polluted air from a high traffic density area nearby.     

Antimony: a traffic-related element in the atmosphere of Buenos Aires, Argentina

Vehicular traffic is one of the main sources of antimony in highly populated urban areas like Buenos Aires where an overall traffic density of 1 500 000 vehicles per day (corresponding to 7500 vehicles km(-2)) is estimated. In this context, a study was undertaken to ascertain the levels of Sb and other traffic-related elements (TRE) in the atmosphere of this city. To this end, sixty-seven samples of PM-10 particulate matter were collected during eight days in nine representative sampling sites located downtown Buenos Aires and spread over an area of about 30 km2. The collection of particulate matter was performed on ash-free glass-fibre filters using high volume samplers with PM-10 sampling heads. A combination of aqua regia and perchloric acid was used for leaching metals from filters. The resulting solutions were evaporated and then diluted with 0.1 mol l(-1) HCl. Antimony was determined by inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) at ng g(-1) levels. Concentrations of Sb varied from 12.9 +/- 0.9 to 375 +/- 23 microg g(-1)(equivalent to 0.87 +/- 0.06 to 15.3 +/- 0.8 ng m(-3)). Statistical analysis was performed on the data set including the measured PM-10 mass and Sb concentrations for the monitored period. Correlations of Sb with other TRE namely, Cu and Mo were also assessed. The highest concentrations of Sb were detected at two sites (Hospital Alemán and Casa Rapallini) located in streets with traffic consisting mostly of passenger cars and showing a "stop-and-go" pattern in peak hours. Antimony levels in the Buenos Aires PM-10 are by far below the level of 0.5 mg m(-3)(for an 8 hour workday, 40 hour work week) set by the US Occupational Safety and Health Administration (OSHA) for occupational exposure. However, monitoring of Sb and other TRE should be carried out in a systematic fashion to detect the possibility of increases in from the present levels.     

Effect of a reservoir in the water quality of the Reconquista River, Buenos Aires, Argentina

The lower portion of the Reconquista River is highly polluted. However, little is known about the state of the high and middle basins. The aims of this work were to assess the water quality on the high and middle Reconquista River basins and to determinate if the presence of a reservoir in the river has a positive effect on the water quality. We conducted a seasonal study between August 2009 and November 2010 at the mouth of La Choza, Durazno, and La Horqueta streams at the Roggero reservoir—which receives the water from the former streams—at the origin of the Reconquista River and 17 km downstream from the reservoir. We measured 25 physical and chemical parameters, including six heavy metal concentrations, and performed a multivariate statistical analysis to summarize the information and allow the interpretation of the whole data set. We found that the Durazno and La Horqueta streams had better water quality than La Choza, and the presence of the reservoir contributed to the improvement of the water quality, allowing oxygenation of the water body and processing of organic matter and ammonia. The water quality of the Reconquista River at its origin is good and similar to the reservoir, but a few kilometers downstream, the water quality declines as a consequence of the presence of industries and human settlements. Therefore, the Roggero reservoir produces a significant improvement of water quality of the river, but the discharge of contaminants downstream quickly reverses this effect.     

An Analysis of Secondary Pollutants in Buenos Aires City

Air pollutant concentrations from a monitoring campaign in Buenos Aires City, Argentina, are used to investigate the relationships between ambient levels of ozone (O₃), nitric oxide (NO) and nitrogen dioxide (NO₂) as a function of NO _x (=NO + NO₂). This campaign undertaken by the electricity sector was aimed at elucidating the apportionment of thermal power plants to air quality deterioration. Concentrations of carbon monoxide (CO) and sulphur dioxide (SO₂) were also registered. Photo stationary state (PSS) of the NO, NO₂, O₃ and peroxy radicals species has been analysed. The ‘oxidant’ level concept has been introduced, OX (=O₃ + NO₂), which varies with the level of NO _x . It is shown that this level is made up of NO _x -independent and NO _x -dependent contributions. The former is a regional contribution that equates the background O₃ level, whereas the latter is a local contribution that correlates with the level of primary pollution. Furthermore, the anticorrelation between NO₂ and O₃ levels, which is a characteristic of the atmospheric photo stationary cycle has been verified.The analysis of the concentration of the primary pollutants CO and NO strongly suggests that the vehicle traffic is the principal source of them. Levels of continuous measurements of SO₂ for Buenos Aires City are reported in this work as a complement of previously published results.     

Air pollution sources of PM10 in Buenos Aires City

To elucidate the sources of PM(10) air pollution from the experimental information collected in a local air quality monitoring campaign we have applied two methods, effective variance and genetic algorithms, in the solution of the chemical mass balance. The comparison of these two mathematical approaches show that the identification of the possible sources and the evaluation of its contributions are quite independent of them. The role of possible different sources for major and trace elements and the significance of standardizing available data is also addressed. We also present a simple method for identifying the number of candidate sources, a key element defining the dimension of the search space.     

The effects of hydraulic works and wetlands function in the Salado-River basin (Buenos Aires,Argentina)

Man-made activities exert great influences on fluvial ecosystems, with lowland rivers being substantially modified through agricultural land use and populations. The recent construction of drainage canals in the upper stretch of the Salado-River basin caused the mobilization of huge amounts of salts formerly stored in the groundwater. The main aim of this work was to analyze the effect of the discharges of those canals into the Salado-River water, under different hydrologic conditions, and the role of the wetlands and shallow lakes placed along the canals’ system. Physicochemical variables were measured and water samples were taken during times of high water, mean flows, drought, and extreme drought. The environmental variables and the plankton development were related to the hydrologic regime and reached minimum values during floods because of low temperatures and dilution. Local effects on the water’s ionic composition became pronounced during droughts because of groundwater input. Nutrient concentrations were mainly associated with point wastewater discharges. Conductivity, ion concentrations, total plankton biomass, and species richness increased in the Salado-River downstream site, after the canals’ discharges. The artificial-drainage system definitely promotes the incorporation of salts into the Salado-River basin. In this scenario, a careful hydraulic management is needed to take into account this issue of secondary salinization that threatens the economic exploitation of the region. The wetlands present in this study acted as service environments not only helping to reduce salt, nutrient, and suspended-solid concentrations downstream but also contributing a plethora of species and plankton biomass into the Salado-River main course.     

Spatial and Temporal Trends of Physicochemical Parameters in the Water of the Reconquista River (Buenos Aires, Argentina)

The Reconquista river is one of the most polluted watercourses in Argentina. More than 3 million people and over 10,000 industries are settled on its basin. The available data show that pollution is mainly related to the discharge of domestic and industrial liquid wastes that are poured into the river almost untreated. At present no site of the river can be characterized as free of pollutants. Samples were taken monthly from 5 sites of the river; some 18–20 physicochemical parameters were determined in each sample. Analyses revealed significant differences in the degree of deterioration between sites. Two of them, close to the source of the river (Cascallares-S₁ and Paso del Rey-S₂) resulted less polluted than the two points located close to the mouth of the river (San Martin-S₄ and Bancalari-S₅). The worsening of the water quality in S₄–S₅ was attributed to the discharges of the Moron stream, a tributary that flows into the main course of the river a complex mixture of non treated waste waters. PCA was used in the ordination of samples (sites, season and physicochemical parameters). In the PCA performed using all variables, the first principal component showed positive correlation with N-NH₄ ⁺, conductivity, orthophosphate, BOD₅, COD and alkalinity, and negative correlation with DO. The second principal component was positively correlated with pH, temperature and chlorophyll a and negatively with phenols and hardness. In respect to the spatial distribution, the plot of the scores for the first two components of samples taken in each sampling station showed S₁ and S₂ values displayed farthest at the left side of the X axis with high DO. In contrast, S₄ and S₅ values stayed at the right side of this axis with high N-NH₄ ⁺, conductivity, orthophosphate, BOD₅, COD and alkalinity; data of S₃ were “intermediate". In order to identify seasonal trends in the concentration of contaminants scores of cases labeled by season were plotted. The line drawn on the ordination plane showed that summer samples tended to converge to the upper right portion of the graph where pollution variables had more importance on the first axis, and along the second axis with high correlation with pH, temperature and chlorophyll a. Winter scores were settled in the left lower part of the plot with minor contribution of pollution parameters and more importance of DO on the first axis. Samples of autumn and spring did not fit a clear cut pattern. Deceased     

Simplified determination of lipophilic metabolites of nonylphenol ethoxylates: method development and application in aqueous samples from Buenos Aires, Argentina

In the present work we have developed an analytical methodology for the determination of nonylphenol (NP) and nonylphenol mono- and di-ethoxylates (NP1EO and NP2EO) in water samples. The applicability of this methodology was proved by means of the analysis of environmentally relevant aqueous samples from Buenos Aires. This constitutes a starting point for a rigorous assessment of the incidence of NPnEO surfactants in Argentina, as only very few, qualitative or semi-quantitative data on the occurrence of these compounds in local systems were available up to this time. Enrichment of the analytes was carried out by solid-phase extraction on a C-18 sorbent, followed by elution with ethyl acetate. Normal-phase high performance liquid chromatography on an amino-silica column and fluorescence detection at excitation-emission wavelengths of 230-300 nm were employed for separation and quantification of the analytes. Confirmation of peak assignment in selected real samples was performed by off-line coupling HPLC with GC-MS analysis. A non-polar GC capillary column was used, and a characteristic peak pattern was obtained for the alkyl chain isomers of each ethoxylated homologue and NP. GC-MS analyses yielded in all cases purity levels higher than 80% for the HPLC collected fractions. The elevated concentrations found for the estrogenic metabolites of NPnEO are in accordance with an unrestricted use of this class of non-ionic surfactants in the country.     

The occurrence of Shiga toxin-producing Escherichia coli in bathing water of the Sierra de la Ventana region, Buenos Aires Province, Argentina

The region of Sierra de la Ventana is located in the southwest of Buenos Aires Province, Argentina. Traditionally, this area has been devoted to livestock and agriculture, but tourism has had a significant development in recent years. In the region, there are many rivers and streams that are used for swimming and bathing. A survey of the occurrence of Shiga toxin-producing Escherichia coli (STEC) in these waters was conducted, and the microbiological quality of rivers and streams was investigated. No E. coli O157 was recovered by immunomagnetic separation. Nevertheless, the Shiga toxin gene, exclusively stx2 genotype, was detected in four non-O157 E. coli strains. Two STEC strains carried eae factor, but none of them harbored the EHEC-hlyA gene. Three of the STEC isolates belonged to samples obtained in the warm months, and one to the winter sampling. In the sample sites where STEC strains were isolated the counts of E. coli/100 ml exceeded or were close to the limit recommended by the United States Environmental Protection Agency for bathing water. The relationship observed between the rainy season and E. coli counts suggests that among the main causes for the hygienic indicator increase is the runoff of manure deposited on soils that may also induce the entrance of pathogens into the aquatic environment. This research, the first reporting STEC isolation from recreational waters in this area, revealed that streams and rivers from a beef-producing area of Argentina are a reservoir of STEC strains.     

Design of an Air-Quality Surveillance System for Buenos Aires City Integrated by a NO x Monitoring Network and Atmospheric Dispersion Models

This paper presents an air-quality surveillance system designed to detect the occurrence of air pollutant concentrations greater than a reference level in an urban area. The system is integrated by an air-quality monitoring network and atmospheric dispersion models simulations. An objective methodology to design an urban air-quality monitoring network is proposed. This methodology is based on the analysis of air-quality modelling results. The procedure is applied to design an air-quality monitoring network to control NO _x concentration levels in Buenos Aires City. Results indicate that six monitors will detect the occurrence of concentration greater than the air-quality guidelines with an efficiency of about 67%. Once a violation is detected, results of atmospheric dispersion models will help in the determination of affected areas. Four possible examples are included to illustrate the assistance that the results of atmospheric dispersion models can bring to a better estimation of possible affected areas in the city. Combining these results with the last census data, an estimation of the inhabitants possibly exposed is obtained.     

Use of tree bark for comparing environmental pollution in different sites from Buenos Aires and Montevideo

Multi-elemental profiles in bark of green ash trees collected in three representative areas of Buenos Aires, Argentina and Montevideo, Uruguay, were assessed as potential air pollution indicators. Ten elements: Al, Ba, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn, were measured using inductively coupled plasma optical emissions spectrometry from 70 samples collected in different environments: central, residential and rural (reference site), in order to compare spatial patterns of metal concentration. The samples used as a control were collected from a nature reserve situated far away from any significant influences, not even a nearby road. The reference site (RF) exhibited the lowest concentrations of Al, Cr, Fe, Ni, Pb, and Zn. However, Ba and Mn showed similar concentrations in all measured sites. Magnesium is the only element that had a greater concentration in RF than at the other sites. Copper did not show any clear pattern. The Centre of Montevideo (MVD) showed higher concentrations of Al, Ba, Cr, Fe, Pb and Zn than the Centre of Buenos Aires (BA). In the A sectors, Montevideo (SAMVD) showed higher concentrations of Al, Cu, Mg, Ni, and Zn and lower concentrations of Ba, Cr, Fe, Mn, and Pb than Buenos Aires (SABA). In the B sectors, Montevideo (SBMVD) showed higher concentrations of Al, Ba, Cu, Fe, Pb, and Zn and lower concentrations of Cr and Mg than Buenos Aires (SBBA), but similar concentrations of Mn and Ni. The use of bark for biomonitoring metals allowed us to detect concentration differences related to the urban fabric and the different kinds of vehicles and their fuels. In the cities, the differences in metal concentrations detected in bark were more striking between the sectors than between centers, despite CBA being much larger than CMVD in population, extension and vehicular traffic.     

深圳市罗湖区道路交通噪声地图的制作与应用

以 SoundPLAN 软件为依托,将罗湖区城市主干道路及周边地物进行概化、建模,并根据实际监测数据调试参数,制作出罗湖区主干道路噪声分布地图,并对噪声污染严重路段防护措施进行效果模拟,为罗湖区道路交通噪声控制规划和整治以及建设项目审批管理等提供依据。     

Urban Development and Air Quality in San Luis City, Argentina

Some factors such as the high population growth, along with insufficient housing, health and sanitary services, obsolete industrial technology and the lack of environmental management programs, give rise to contamination in Latin-American cities. Owing to the urban characteristics of San Luis, a detailed analysis of air quality was planned as part of a more comprehensive study, in order to make an environmental diagnosis of the city after the demographical and economic upgrowth over the last 15 years. It has been concluded that air pollution levels in San Luis are higher than those expected for a medium-size city. The reported high levels were attributed to important industrial activity, responsible not only for the direct of polluting gases to the atmosphere but also as the principal cause of the urban expansion. The levels of CO and SO₂ (ppm) found in the city can be considered as high. Some weeks during the sampling measure values were appreciably higher than the maximum tolerance levels established. The urban area under study was separated into five defined areas, which allowed to make comparisons in order to identify specific contamination problems. The slopes corresponding to the plot polluting substances concentration vs. wind speed were lower than the expected values. Because of the urban area characteristics, different micrometeorological effects facilitating a low air exchange can be generated, and consequently increasing the contamination levels. Thus, it is correct to conclude that the degradation processes are not occurring in a single environmental plane. Accordingly, air contamination rate in San Luis city could be considered as evidence of other upper-scale regional environmental degradation processes.     

城市噪声对校园的干扰类型与特征浅析

对阿图什市区各学校所受的周边环境噪声干扰情况进行了监测，运用声环境评价方法，将市区10所学校校园划分为清静型、扰闹型和持续吵闹型3种噪声干扰类型。分析了各类型的特征和成因，并提出防治措施。     

南京市典型快速路交通噪声监测与影响分布研究

为科学全面地开展城市道路交通噪声影响评估，更精确地服务道路交通噪声污染治理工作，选取南京市具有代表性的道路交通干线，采用手工监测和自动连续监测的方法，进行不同路段噪声污染程度及其随时间、空间变化规律的研究。结果表明，地面快速路段、高架路段以及衔接路段两侧噪声敏感建筑物受道路交通噪声影响较大，夜间均超标；相邻区域要达到2类声环境功能区昼间标准限值要求，需距离地面快速路慢车道约45 m，距离高架路段慢车道约92 m；要达到2类声环境功能区夜间标准限值要求，需距离地面快速路慢车道约175 m，距离高架路段慢车道约172 m；敏感建筑物所受噪声影响随楼层高度升高而增大，同时噪声影响情况与道路两侧建筑物密度、道路车辆行驶速度有关。建议严格道路及噪声敏感建筑物规划控制，采取阻断传声路径、受声建筑物强化保护等措施控制噪声影响。     

广州市昼夜道路交通噪声的监测与分析

对广州市的昼夜交通噪声污染现状进行了分区域分道路等级的实地监测,得到共53个监测点位白天和夜晚的等效声级及其统计声级,同时对每个监测点展开了交通流调查,并分析交通流特征对交通噪声的影响。监测结果表明, 白天快速路、主干路、次干路及支路的平均等效声级分别为74.2、72.2、67.8、65.1 dB,快速路及主干路沿线的交通噪声污染比次干路及支路的严重。夜晚所有测点的噪声值均超过55 dB,快速路、主干路、次干路及支路的平均等效声级分别为72.2、72.3、66.3、64.5 dB,广州市夜晚的交通噪声污染较为严重。     

Study of meteorological aspects and urban concentration of SO2 in atmospheric environment of La Plata, Argentina

This article presents and discusses SO(2) (ppbv) concentration measurements combined with meteorological data (mainly wind speed and direction) for a five-year campaign (1996 to 2000), in a site near an oil refinery plant close to the city of La Plata and surroundings (aprox. 740.000 inh.), considered one of the six most affected cities by air pollution in the country. Since there is no monitoring network in the area, the obtained results should be considered as medium term accumulated data that enables to determine trends by analyzing together gas concentrations and meteorological parameters. Preliminary characterization of the behaviour of the predominant winds of the region in relation with potential atmospheric gas pollutants from seasonal wind roses is possible to carry out from the data. These results are complemented with monthly averaged SO(2) measurements. In particular, for year 2000, pollutant roses were determined which enable predictions about contamination emission sources. As a general result we can state that there is a clear increase in annual SO(2) concentration and that the selected site should be considered as a key site for future survey monitoring network deployment. Annual SO(2) average concentration and prevailing seasonal winds determined in this work, together with the potential health impact of SO(2) reveals the need for a comprehensive and systematic study involving particulate matter an other basic pollutant gases.     

Study of Meteorological Aspects and Urban Concentration of SO2 in Atmospheric Environment of La Plata, Argentina

This article presents and discusses SO₂ (ppbv) concentration measurements combined with meteorological data (mainly wind speed and direction) for a five-year campaign (1996 to 2000), in a site near an oil refinery plant close to the city of La Plata and surroundings (aprox. 740.000 inh.), considered one of the six most affected cities by air pollution in the country. Since there is no monitoring network in the area, the obtained results should be considered as medium term accumulated data that enables to determine trends by analyzing together gas concentrations and meteorological parameters. Preliminary characterization of the behaviour of the predominant winds of the region in relation with potential atmospheric gas pollutants from seasonal wind roses is possible to carry out from the data. These results are complemented with monthly averaged SO₂ measurements. In particular, for year 2000, pollutant roses were determined which enable predictions about contamination emission sources. As a general result we can state that there is a clear increase in annual SO₂ concentration and that the selected site should be considered as a key site for future survey monitoring network deployment. Annual SO₂ average concentration and prevailing seasonal winds determined in this work, together with the potential health impact of SO₂ reveals the need for a comprehensive and systematic study involving particulate matter an other basic pollutant gases.     

青岛市主干道沿线高层建筑的交通噪声研究

采用A计权网络对青岛市东西快速路沿线高层建筑进行监测。利用Grapher软件,以Leq为监测值的基准值绘制连续线状图,分析城市主干道周边高层建筑上交通噪声的峰值点。根据道路中心线到高层建筑的距离信息,得出高层建筑交通噪声峰值点与道路中心线的连线与水平地面间的角度约为30°。