Spatial distribution of heavy metal concentrations in urban, suburban and agricultural soils in a Mediterranean city of Algeria

As part of a larger program aiming at assessing transfer and effects of metals in food webs, this work studied the spatial distribution of Cd, Cr, Cu, Pb, and Zn in 101 sub-surface soils, systematically sampled (1 × 1 km regular grid) over a large area around Annaba, the fourth most-populated city of Algeria. Cd and Cr exhibited only one abnormally high value, with all other concentrations being close to pedogeological background. Some places in the centre of the city were polluted by Pb (up to 823 mg kg⁻¹), probably due to aerial deposition from gasoline exhausts. Zn never exceeded regulatory limits over the whole sampling area. Cu was the only element for which a spatial autocorrelation occurred. A spatial interpolation by cokriging allowed the identification of agricultural activities as the main Cu pollution source. Our approach revealed various anthropogenic pollution sources, more efficiently for large-scale patterns than for local abnormalities.     

Size distribution of polycyclic aromatic hydrocarbons in urban and suburban sites of Beijing, China

PAHs in five-stage size segregated aerosol particles were investigated in 2003 at urban and suburban sites of Beijing. The total concentration of 17 PAHs ranged between 0.84 and 152 ng m(-3), with an average of 116 ng m(-3), in urban area were 1.1-6.6 times higher than those measured in suburban area. It suggested a serious pollution level of PAHs in Beijing. PAHs concentrations increased with decreasing the ambient temperature. Approximately 68.4-84.7% of PAHs were adsorbed on particles having aerodynamic diameter 2.0 microm. Nearly bimodal distribution was found for PAHs with two and three rings, more than four rings PAHs, however, followed unimodal distribution. The overall mass median diameter (MMD) for PAHs decreased with increasing molecular weight. Diagnostic ratios and normalized distribution of PAHs indicated that the PAHs in aerosol particles were mainly derived from fossil fuel combustion. Coal combustion for domestic heating was probably major contributor to the higher PAHs loading in winter, whereas PAHs in other seasons displayed characteristic of mixed source of gasoline and diesel vehicle exhaust. Biomass burning and road dust are minor contributors to the PAHs composition of these aerosol particles. Except for source emission, other factors, such as meteorological condition, photochemical decay, and transportation from source to the receptor site, should to be involved in the generation of the observed patterns.     

Differences between carbon dioxide levels over suburban and rural sites in Northern Spain

Purpose  

A comparison between suburban and rural atmospheric carbon dioxide concentrations in Northern Spain is made.     

Characteristics and diurnal variations of NMHCs at urban,suburban, and rural sites in the Pearl River Delta and a remote site in South China

The Pearl River Delta (PRD) is one of the most industrialized and urbanized regions in China. With rapid growth of the economy, it is suffering from deteriorating air quality. Non-methane hydrocarbons (NMHCs) were investigated at urban and suburban sites in Guangzhou (GZ), a rural site in PRD and a clean remote site in South China, in April 2005. Additional roadside samples in GZ and Qingxi (QX, a small industrial town in PRD), ambient air samples at the rooftop of a printing factory in QX and exhaust samples from liquefied petroleum gas (LPG)—fueled taxis in GZ were collected to help identify the source signatures of NMHCs. A large fraction of propane (47%) was found in exhaust samples from LPG-fueled taxis in GZ and extremely high levels of toluene (2.0–3.1 ppmv) were found at the rooftop of the printing factory in QX. Vehicular and industrial emissions were the main sources of NMHCs. The effect of vehicular emission on the ambient air varied among the three PRD sites. The impact of industrial emissions was widespread and they contributed greatly to the high levels of aromatic hydrocarbons, especially toluene, at the three PRD sites investigated. Leakage from vehicles fueled by LPG contributed mainly to the high levels of propane and n-butane at the urban GZ site. Ethane and ethyne from long-range transport and isoprene from local biogenic emission were the main contributors to the total hydrocarbons at the remote site. Diurnal variations of NMHCs showed that the contribution from vehicular emissions varied with traffic conditions and were more influenced by fresh emissions at the urban site and by aged air at the suburban and rural sites. Isoprene from biogenic emission contributed largely to the ozone formation potential (OFP) at the remote site. Ethene, toluene and m/p-xylene were the main contributors to the OFP at the three PRD sites.     

Surface ozone at rural sites in the latrobe valley and Cape Grim,Australia

Ozone and other air quality data from five rural sites in the industrialized Latrobe Valley, Victoria, have been subject to statistical analyses including linear regression modelling. The behaviour of O₃ in the Latrobe Valley is explained largely in terms of natural background atmospheric processes as observed at Cape Grim, Tasmania.The maximum 1-h average concentration of naturally occurring O₃ (obtained from a 6-year record at Cape Grim) is less than 40 ppb (v/v). In contrast the industrialized Latrobe Valley sites show O₃ values exceeding 40 ppb between 1% and 3% of the time. These higher concentrations occur in conditions consistent with local photochemical production of O₃ via ‘smog’ type processes and appear preferentially at low NO_x concentrations (3–4 ppb) during the afternoon (13–18 h) and at high temperatures (above 25°C).A comparison of observations from an elevated station (750 m) with those from the valley floor shows systematic differences in seasonal and diurnal O₃ variations and the time of day of occurrence of elevated O₃ concentrations which can be explained in terms of the diurnal cycle of convective mixing and mountain/valley winds.A linear regression model incorporating this understanding has accounted for between 43% and 64% of the variance of O₃ concentration at the elevated and rural stations. The statistical model incorporates temperature, time of day, month of year, wind speed, O₃ concentration 24-h earlier and NO_x concentration as variables in the regression equation, with temperature being the dominant variable. The standard deviation of the residual O₃ values (observed minus fitted) is around 5 ppb. Auto and cross correlations are used to show that perhaps half of the unexplained variance is coherent from site to site and hence potentially could be modelled.     

Seasonal concentrations and partitioning of PAHs in a suburban site of Bursa, Turkey

Effects of space heating on atmospheric concentrations and gas-particle partitioning of PAHs were investigated in a suburban site of Bursa, Turkey. The average concentrations of ∑₁₅-PAHs in heating season samples were approximately 10 times higher than those of non-heating season samples. The plot of log K_p versus log P_L⁰ for all the data set gave significantly different slopes. The slope for the heating season (−0.75) samples was steeper than the one for the non-heating season (−0.64) samples. It was also observed that partitioning of PAHs for the non-heating season samples showed different characteristics depending on air parcel trajectories. Generally steeper slopes were obtained for the air parcels traveled across the Black sea and arrived to the sampling site from northern sector. On the other hand, the variations in slopes according to air mass origin were insignificant for the heating season samples. Local contributions from space heating are the reason for this observation.     

Characterization of PM10 atmospheric aerosol at urban and urban background sites in Fuzhou city, China

Background

PM₁₀ aerosol samples were simultaneously collected at two urban and one urban background sites in Fuzhou city during two sampling campaigns in summer and winter. PM₁₀ mass concentrations and chemical compositions were determined.

Methods

Water-soluble inorganic ions (Cl^?, NO ₃ ^? , SO ₄ ^2? , NH ₄ ⁺ , K⁺, Na⁺, Ca²⁺, and Mg²⁺), carbonaceous species (elemental carbon and organic carbon), and elements (Al, Si, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, and Pb) were detected using ion chromatography, thermal/optical reflectance, and proton-induced X-ray emission methods, respectively.

Results

PM₁₀ mass concentrations, as well as most of the chemical components, were significantly increased from urban background to urban sites, which were due to enhanced anthropogenic activities in urban areas. Elements, carbonaceous species, and most of the ions were more uniformly distributed at different types of sites in winter, whereas secondary ion SO ₄ ^2? , NO ₃ ^? , and NH ₄ ⁺ showed more evident urban-background contrast in this season. The chemical mass closure indicated that mineral dust, organic matters, and sulfate were the most abundant components in PM₁₀. The sum of individually measured components accounted for 86.9?C97.7% of the total measured PM₁₀ concentration, and the discrepancy was larger in urban area than in urban background area.

Conclusion

According to the principal component analysis?Cmultivariate linear regression model, mineral dust, secondary inorganic ions, sea salt, and motor vehicle were mainly responsible for the PM₁₀ particles in Fuzhou atmosphere, and contributed 19.9%, 53.3%, 21.3%, and 5.5% of PM₁₀, respectively.     

Variability of Nox and No2 concentrations observed at pedestrian level in the city centre of a medium sized urban area

NO_x and NO₂ concentrations were measured at different locations in a city centre of an urban zone (Population 450 000) in order to study the variation of the outdoor exposure at pedestrian level. These measurements were carried out to understand the influence of traffic emissions at each measured site. The observations were done during four weeks in winter, including several days with high pollution levels. The results at different locations have been used to analyse criteria recommended for locating observation sites in a monitoring network. No large differences in background pollution averaged over several weeks have been found throughout the city centre, even during pollution peaks. Measurements were also carried out inside one street canyon. The contribution of the street traffic to the NO=NO_x−NO₂ concentrations observed at side-walk has been found important, i.e., several times the background level. On the other hand, the majority of observed NO₂ pollution is due to the contribution of background pollution within the street. The pollutant excess at pedestrian level is strongly correlated to the street traffic emission and to the atmospheric turbulence observed at roof level. Application of a box model to the street data demonstrates that such models can be useful to estimate the pollutant accumulation within the street.     

Ozone pollution and ozone biomonitoring in European cities. Part I: Ozone concentrations and cumulative exposure indices at urban and suburban sites

In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed based on hourly mean values, and cumulative ozone exposure indices (Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a strong rise during the morning, peak concentrations in the afternoon, and a decline during the night. The widest amplitudes between minimum and maximum values were found in central and southern European cities such as Düsseldorf, Verona, Klagenfurt, Lyon or Barcelona. In the northern European cities of Edinburgh and Copenhagen, by contrast, maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as on cumulative exposure indices, a clear north–south gradient in ozone pollution, with increasing levels from northern and northwestern sites to central and southern European sites, was observed. Only the Spanish cities did not fit this pattern; there, ozone levels were again lower than in central European cities, probably due to the direct influence of strong car traffic emissions. In general, ozone concentrations and cumulative exposure were significantly higher at suburban sites than at urban and traffic-exposed sites. When applying the newly established European Union (EU) Directive on ozone pollution in ambient air, it was demonstrated that the target value for the protection of human health was regularly surpassed at urban as well as suburban sites, particularly in cities in Austria, France, northern Italy and southern Germany. European target values and long-term objectives for the protection of vegetation expressed as AOT40 were also exceeded at many monitoring sites.     

Source identification of nickel in TSP and PM2.5 in Tokyo,Japan

This study investigates the source identification of nickel in the aerosol of the Tokyo metropolitan area. TSP and PM_2.5 samples were collected daily from August to November 2004. The samples were examined by means of the water-extraction method, followed by elemental analysis and SEM/EDX analysis. We distinguished two types of atmospheric nickel sources in the studied area: (1) particles derived from heavy oil combustion, distributed mostly in fine particles such as PM_2.5, relatively water-soluble, and containing vanadium and (2) particles derived from mechanical abrasion/erosion of metallic surfaces, distributed in coarse particles such as TSP, relatively water-insoluble, and containing chromium.     

城郊气象因素与NOx、PM10的多重分形分析

针对城区和郊区气象因素与NOx、PM10浓度间的互相关性的特征,采用多重分形去趋势波动互相关分析法（MF-DCCA）,对气象因素与NOx、PM10浓度时间序列进行研究。首先验证了温度与NOx、PM10具有互相关性和多重分形特征,然后,逐次分析城区和郊区在夏冬两季温度、湿度、风速、气压与NOx、PM10的多重分形特征。结果表明,城区天气因素与PM10、NOx的多重分形特征要强于郊区,两地天气因素对PM10的影响程度要强于对NOx的程度,城区和郊区夏季的天气因素与PM10的多重分形特征均强于冬季。     

合肥城郊典型排水沟渠沉积物磷形态及其释放风险

为弄清合肥市城郊排水沟渠-关镇河水体沉积物磷赋存形态及其污染特征,于2013年9月-2014年6月,在沟渠上选取8个采样点,逐月采集水样和表层沉积物样,解析沉积物的磷赋存形态及其时空变化特征,并对磷的潜在释放风险进行分析。结果表明:关镇河水体氮、磷污染严重;沉积物中TP含量处于1430.10~1941.26 mg/kg范围,平均为1734.42 mg/kg;沉积物各形态磷含量由高到低排序为:OP > Fe-P > Ca-P > De-P > Al-P > Oc-P > Ex-P;生物有效性磷平均值为464.01 mg/kg,占TP的26.81%;广义生物有效性磷的平均含量为1226.92 mg/kg,占TP的71.00%;PSI变化范围为18.31~69.96 mg P/(100 g)·(μmol/L),且沉积物磷释放风险春夏季高于秋冬季。     

Forty years studies on polychlorinated biphenyls pollution,food safety,health risk,and human health in an e-waste recycling area from Taizhou city,China: a review

Environmental Science and Pollution Research - E-waste generation has become a serious environmental challenge worldwide. Taizhou of Zhejiang Province, situated on the southeast coastline of China,...     

Robinsonecio gerberifolius as a sentinel organism for atmospheric pollution by heavy metals in several sites of Mexico city and its metropolitan area

Environmental Science and Pollution Research - Evaluate the effect of heavy metals (HM) on sentinel organisms such as vascular plants represent a model to estimate toxic hazard due to environmental...     

Comparison of particulate mass, chemical species for urban, suburban and rural areas in central Taiwan, Taichung

Aerosol samples for PM2.5, PM(2.5-10) and TSP were collected from June to September 1998 and from February to March 1999 in central Taiwan. Ion chromatography was used to analyze the acidic anions: sulfate, nitrate and chloride in the Universal samples. The ratios of fine particle concentrations to coarse particle concentrations displayed that the fine particle concentrations are almost greater than that of coarse particle concentrations in Taichung area. The average concentrations of PM2.5, PM(2.5-10) and TSP in urban sites are higher than in suburban and rural sites at both daytime and night-time. Chloride dominated in the coarse mode in daytime and in fine mode in night-time. Nitrate can be found in both the coarse and fine modes. Sulfate dominated in fine mode in both daytime and night-time.     

The study of fine and coarse particles, and metallic elements for the daytime and night-time in a suburban area of central Taiwan, Taichung

Daily average concentrations of fine and coarse particulates, and TSP samples have been measured simultaneously at daytime and night-time periods by using Universal and PS-1 sampler in a suburban area of central Taiwan from June to August 1998. The samples were analyzed by atomic absorption spectrometry to determine the fine and coarse particulate concentrations of metallic elements (Ca, Fe, Mn, Pb, Cu, Zn and Cr). The concentration of PM2.5 and TSP showed a decreased trend for the daytime period. The fine particle concentrations were about two times as that of coarse particulate concentrations. The averaged fine particulate concentrations at daytime are higher than at night-time. Ca and Fe were mostly in the coarse particulate mode. The correlation coefficients were 0.63 and 0.69 for elements Ca and Fe in the coarse particle mode for day and night periods. Pb showed a similar distribution ratio with Mn for the fine to coarse particle ratios at both day and night period. Pb and Mn are highly correlated for the day (R = 0.78) and night period (R = 0.61) at particle size <2.5 microm. Cu and Zn were mainly in fine particles at both day and night period. Fe and Ca consist of the major parts of all the elements. Elemental Mn is the lowest among the rest of the heavy metals.     

成都市区、城郊和农村生活垃圾重金属污染特性及来源

以快速发展的城郊地区为切入点,研究了成都市区、城郊和农村三区冬夏两季生活垃圾的物理组成、重金属污染特性和来源。研究发现,成都地区生活垃圾重金属浓度普遍高于当地土壤背景值,且呈现出夏季高于冬季的趋势。无论冬夏,三区垃圾中最主要的污染重金属均为Se(0.3~1.1 mg/kg)、Cd(0.3~0.9 mg/kg)和Cu(24.9~152.6 mg/kg),而其他重金属污染物如Pb、Hg和Cr在三区垃圾中的污染强弱顺序差异较大。通过Pearson相关性分析以及测定垃圾主成分中重金属浓度来研究重金属污染物的来源,结果显示:三区生活垃圾中Cd主要源于餐厨、尘土和塑料,Se可能源于废弃的电子产品,Cu和Zn源于尘土和包装纸;市区垃圾中的Pb主要源于尘土、塑料和包装纸;城郊垃圾中Cr、Se的主要源于尘土,而Hg主要来源于餐厨和尘土。     

上海城郊大气挥发性有机物污染特征、活性组分及风险评估

为了解上海城郊大气中挥发性有机物(VOCs)的时空污染特征及其对人体潜在健康风险,选取上海某城郊10个点位进行连续6年(2012—2017年)的采样分析。结果表明,上海该城郊大气VOCs平均质量浓度为(243.80±151.52)μg/m3,其中烷烃、卤代烃、芳香烃、含氧VOCs和不饱和脂肪烃依次占VOCs总浓度的45.72%、20.04%、18.84%、11.19%、4.21%。上海郊区不同功能区VOCs总浓度年际变化趋势较为一致,总体呈下降趋势;在空间上,化工区主干道路附近的两采样点VOCs质量浓度最高,分别为307.81、340.97μg/m~3。O3生成潜势和等效丙烯浓度计算结果显示,芳香烃为上海城郊大气中最主要的活性物种,且关键活性组分为甲苯、间/对-二甲苯和异丁烷等。上海城郊大气中27种风险VOCs的总致癌风险值为3.02×10~(-4),高于可接受限值(1.00×10~(-4)),长期暴露可能有致癌风险。