The dust retention capacities of urban vegetation—a case study of Guangzhou, South China

Urban vegetation increasingly plays an important role in the improvement of the urban atmospheric environment. This paper deals with the dust retention capacities of four urban tree species (Ficus virens var. sublanceolata, Ficus microcarpa, Bauhinia blakeana, and Mangifera indica Linn) in Guangzhou. The dust-retaining capacities of four tree species are studied under different pollution intensities and for different seasons. Remote sensing imagery was used to estimate the total aboveground urban vegetation biomass in different functional areas of urban Guangzhou, information that was then used to estimate the dust-retaining capacities of the different functional areas and the total removal of airborne particulates in urban Guangzhou by foliage. The results showed that urban vegetation can remove dust from the atmosphere thereby improving air quality. The major findings are that dust retention, or capture, vary between the four species of tree studied; it also varied between season and between types of urban functional area, namely industrial, commercial/road traffic, residential, and clean areas. Dust accumulation over time was also studied and reached a maximum, and saturation, after about 24 days. The overall aboveground biomass of urban vegetation in Guangzhou was estimated to be 52.0?×?10⁵ t, its total leaf area 459.01 km², and the dust-retaining capacity was calculated at 8012.89 t per year. The present study demonstrated that the foliage of tree species used in urban greening make a substantial contribution to atmospheric dust removal and retention in urban Guangzhou.     

Ion chemistry of waters impounded by the Ziqlab dam, Jordan, and weathering processes – a case study

The area included in the present investigation is that surrounding Ziqlab dam in the northern Jordan Valley. The water chemistry of the impounded lake shows that it is dominated by Mg, Ca, Na and HCO₃. These waters reflects the dominance of carbonate weathering with some contribution of silicates. Mg + Ca + Na and HCO₃ + Cl account for about 90% of the total cations and anions. X-ray analysis shows that, kaolinte and illite are the dominant clay minerals in sediments behind Ziqlab dam. Anthropogenic activities within the Ziqlab catchments area contribute to increasing of the ionic concentrations. These include various development activities in the catchments area, waste disposal (especially the untreated municipal and domestic sewage) into the Ziqlab River, and agricultural activities. Ziqlab dam water chemistry is within the range of stability field of kaolinite.     

Air quality measurements in urban green areas – a case study

The influence of traffic-induced pollutants (e.g. CO, NO, NO₂ and O₃) on the air quality of urban areas was investigated in the city of Essen, North Rhine-Westphalia (NRW), Germany. Twelve air hygiene profile measuring trips were made to analyse the trace gas distribution in the urban area with high spatial resolution and to compare the air hygiene situation of urban green areas with the overall situation of urban pollution. Seventeen measurements were made to determine the diurnal concentration courses within urban parks (summer conditions: 13 measurements, 530 30 min mean values, winter conditions: 4 measurements, 128 30 min mean values). The measurements were carried out during mainly calm wind and cloudless conditions between February 1995 and March 1996. It was possible to establish highly differentiated spatial concentration patterns within the urban area. These patterns were correlated with five general types of land use (motorway, main road, secondary road, residential area, green area) which were influenced to varying degrees by traffic emissions. Urban parks downwind from the main emission sources show the following typical temporal concentration courses: In summer rush-hour-dependent CO, NO and NO₂ maxima only occurred in the morning. A high NO₂/NO ratio was established during weather conditions with high global radiation intensities (K>800 W m⁻²), which may result in a high O₃ formation potential. Some of the values measured found in one of the parks investigated (Gruga Park, Essen, area: 0.7 km²), which were as high as 275 μg m⁻³ O₃ (30-min mean value) were significantly higher than the German air quality standard of 120 μg m⁻³ (30-min mean value, VDI Guideline 2310, 1996) which currently applies in Germany and about 20% above the maximum values measured on the same day by the network of the North Rhine–Westphalian State Environment Agency. In winter high CO and NO concentrations occur in the morning and during the afternoon rush-hour. The highest concentrations (CO=4.3 mg m⁻³, NO=368 μg m⁻³, 30-min mean values) coincide with the increase in the evening inversion. The maximum measured values for CO, NO and NO₂ do not, however, exceed the German air quality standards in winter and summer.     

Sorption of lead in soil as a function of pH: a study case in México

Reactions of lead sorption onto soil are largely affected by properties and composition of soil and its solution. In this study, the lead sorption onto regosol eutric soil from Francisco I. Madero, Zacatecas, Mexico is evaluated at different pH values. Soil samples were suspended in lead solutions of 10, 25, 50, 100, 150, 200, 300, and 400 mg/l (as Pb(NO3)2). The pH was adjusted at 2, 3, 4, and 5.5 with nitric acid for each of the lead solution concentrations. In all the cases the ionic strength was I=0.09 M with calcium nitrate. The solid-liquid-ratios were fixed in 1:100 and 1:200 g/ml. The results show that lead sorption increases when pH increases. Experimental isotherms were adjusted by both Langmuir and Freundlich models. The Langmuir affinity parameter, K, indicates that the lead sorption capacity of Francisco I. Madero soils is largely perceptible to pH changes.     

Associations of bisphenol exposure with the risk of gestational diabetes mellitus: a nested case–control study in Guangxi,China

Environmental Science and Pollution Research - A growing number of epidemiologic studies have estimated the associations between endocrine-disrupting chemicals and gestational diabetes mellitus...     

Can the environmental health of urban centers be assessed through pollutants trapped in lakes? A study case in the biggest city of the southern hemisphere

Environmental Science and Pollution Research - Air and water quality in urban centers are summited to pollution from different sources, such as industrial activities, traffic, and wastewater...     

CFD investigation on gas–solid two-phase flow of dust removal characteristics for cartridge filter: a case study

Environmental Science and Pollution Research - The filter cartridge dust collector has been widely used in industry, but the influence of its internal structure on its operation effects is rarely...     

Water reuse in industries: analysis of opportunities in the Paraíba do Sul river basin,a case study in Presidente Vargas Plant,Brazil

Environmental Science and Pollution Research - In recent years, the demand for clean water has been growing all over the world despite the different threats posed, including increasing pollution,...     

Potential of Eucalyptus globulus for the phytoremediation of metals in a Moroccan iron mine soil—a case study

Environmental Science and Pollution Research - The contamination left by abandoned mines demands sustainable mitigation measures. Hence, the aim of this study was to examine the phytoremediator...     

Influence of a nickel smelter plant on the mineralogical composition of attic dust in the Tikveš Valley, Republic of Macedonia

Mineral phases and their content were determined in attic dust samples collected from 27 houses in the Tikve? Valley, Republic of Macedonia. By using quantitative X-ray diffraction, the principal mineral phases were determined to be the serpentinite group (chrysotile, lizardite) and amphibole group of minerals (ribecite, tremolite, actinolite) present in the attic dust samples from this region which are not common constituents of urban dust. Strong correlations existed between these mineral phases in the dust and those in ores processed at a ferronickel smelter plant situated in this region. Spatial distributions of specific mineral phases were made and were consistent with wind directions and predicted deposition (60–70 %) of dust emitted from the metallurgical plant.     

Exposure to phthalates in early pregnancy and the risk of fetal growth restriction: a nested case–control study in a Zhuang Chinese population

Environmental Science and Pollution Research - Phthalates (PAEs) are common endocrine disrupting chemicals (EDCs) that disrupt fetal development. The present study aimed to evaluate the effects of...     

Simulation of the influence of industrial wastewater on a municipal sewage treatment plant—a case study

Purpose  

Industrial wastewater flow caused operational difficulties in the wastewater treatment plant in Debrecen, Hungary. Bioaugmentation was successfully applied to maintain effluent quality in the periods when wastewater of high starch content was accepted, but, at the end of 2008, the nitrification capacity of the plant decreased considerably due to improperly pre-treated pharmaceutical wastewater.     

Impacts of urbanization at city cluster scale on ecosystem services along an urban–rural gradient: a case study of Central Yunnan City Cluster,China

Environmental Science and Pollution Research - Urban agglomeration will be the main mode of future urbanization in China, greatly influencing social and economic development and ecosystem...     

Impact of municipal solid waste dumpsites on trace metal contamination levels in the surrounding area: a case study in West Africa,Abidjan, Cote d’Ivoire

Environmental Science and Pollution Research - The impact of uncontrolled municipal dumping sites on metal contamination in the surrounding waters, sediments, and soils are of great concern in many...     

Cost–benefit analysis of using sewage sludge as alternative fuel in a cement plant: a case study

Background, aim, and scope  To enforce the implementation of the Kyoto Protocol targets, a number of governmental/international institutions have launched emission trade schemes as an approach to specify CO₂ caps and to regulate the emission trade in recent years. These schemes have been basically applied for large industrial sectors, including energy producers and energy-intensive users. Among them, cement plants are included among the big greenhouse gas (GHG) emitters. The use of waste as secondary fuel in clinker kilns is currently an intensive practice worldwide. However, people living in the vicinity of cement plants, where alternative fuels are being used, are frequently concerned about the potential increase in health risks. In the present study, a cost–benefit analysis was applied after substituting classical fuel for sewage sludge as an alternative fuel in a clinker kiln in Catalonia, Spain. Materials and methods  The economical benefits resulting in the reduction of CO₂ emissions were compared with the changes in human health risks due to exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and carcinogenic metals (As, Cd, Co, and Cr) before and after using sewage sludge to generate 20% of the thermal energy needed for pyro-processing. The exposure to PCDD/Fs and metals through air inhalation, soil ingestion and dermal absorption was calculated according to the environmental levels in soil. The carcinogenic risks were assessed, and the associated cost for the population was estimated by considering the DG Environment’s recommended value for preventing a statistical fatality (VPF). In turn, the amount of CO₂ emitted was calculated, and the economical saving, according to the market prices, was evaluated. Results  The use of sewage sludge as a substitute of conventional energy meant a probability cancer decrease of 4.60 for metals and a cancer risk increase of 0.04 for PCDD/Fs. Overall, a net reduction of 4.56 cancers for one million people can be estimated. The associated economical evaluation due to the decreasing cancer for 60,000 people, the current population living near the cement plant, would be of 0.56 million euros (US$ 0.83 million). In turn, a reduction of 144,000 tons of CO₂ emitted between 2003 and 2006 was estimated. Considering a cost of 20 euros per ton of CO₂, the global saving would be 2.88 million euros (US$ 4.26 million). Discussion  After the partial substitution of the fuel, the current environmental exposure to metals and PCDD/Fs would even mean a potential decrease of health risks for the individuals living in the vicinity of the cement plant. The total benefit of using sewage sludge as an alternative fuel was calculated in 3.44 million euros (US$ 5.09 million). Environmental economics is becoming an interesting research field to convert environmental benefits (i.e., reduction of health risks, emission of pollutants, etc.) into economical value. Conclusions  The results show, that while the use of sewage sludge as secondary fuel is beneficial for the reduction in GHG emissions, no additional health risks for the population derived from PCDD/F and metal emissions are estimated. Recommendations and perspectives  Cost–benefit analysis seems to be a suitable tool to estimate the environmental damage and benefit associated to industrial processes. Therefore, this should become a generalized practice, mainly for those more impacting sectors such as power industries. On the other hand, the extension of the study could vastly be enlarged by taking into account other potentially emitted GHGs, such as CH₄ and N₂O, as well as other carcinogenic and non-carcinogenic micropollutants.     

Environmental and socioeconomic assessment of impacts by mining activities—a case study in the Certej River catchment,Western Carpathians,Romania

Background, aim and scope

In the region of the Apuseni Mountains, part of the Western Carpathians in Romania, metal mining activities have a long-standing tradition. These mining industries created a clearly beneficial economic development in the region. But their activities also caused impairments to the environment, such as acid mine drainage (AMD) resulting in long-lasting heavy metal pollution of waters and sediments. The study, established in the context of the ESTROM programme, investigated the impact of metal mining activities both from environmental and socioeconomic perspectives and tried to incorporate the results of the two approaches into an integrated proposition for mitigation of mining-related issues.

Study site

The small Certej catchment, situated in the Southern Apuseni Mountains, covers an area of 78 km². About 4,500 inhabitants are living in the basin, in which metal mining was the main economic sector. An open pit and several abandoned underground mines are producing heavy metal-loaded acidic water that is discharged untreated into the main river. The solid wastes of mineral processing plants were deposited in several dumps and tailings impoundment embodying the acidic water-producing mineral pyrite.

Methods

The natural science team collected samples from surface waters, drinking water from dug wells and from groundwater. Filtered and total heavy metals, both after enrichment, and major cations were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Major anions in waters, measured by ion chromatography, alkalinity and acidity were determined by titration. Solid samples were taken from river sediments and from the largest tailings dam. The latter were characterised by X-ray fluorescence and X-ray diffraction. Heavy metals in sediments were analysed after digestion. Simultaneously, the socioeconomic team performed a household survey to evaluate the perception of people related to the river and drinking water pollution by way of a logistic regression analysis.

Results and discussion

The inputs of acid mine waters drastically increased filtered heavy metal concentrations in the Certej River, e.g. Zn up to 130 mg L⁻¹, Fe 100 mg L⁻¹, Cu 2.9 mg L⁻¹, Cd 1.4 mgL⁻¹ as well as those of SO₄ up to 2.2 g L⁻¹. In addition, river water became acidic with pH values of pH 3. Concentrations of pollutant decreased slightly downstream due to dilution by waters from tributaries. Metal concentrations measured at headwater stations reflect background values. They fell in the range of the environmental quality standards proposed in the EU Water Framework Directive for dissolved heavy metals. The outflow of the large tailing impoundment and the groundwater downstream from two tailings dams exhibited the first sign of AMD, but they still had alkalinity.

Most dug wells analysed delivered a drinking water that exhibited no sign of AMD pollution, although these wells were a distance of 7 to 25 m from the contaminated river. It seems that the Certej River does not infiltrate significantly into the groundwater.

Pyrite was identified as the main sulphide mineral in the tailings dam that produces acidity and with calcite representing the AMD-neutralising mineral. The acid–base accounting proved that the potential acid-neutralising capacity in the solid phases would not be sufficient to prevent the production of acidic water in the future. Therefore, the open pits and mine waste deposits have to be seen as the sources for AMD at the present time, with a high long-term potential to produce even more AMD in the future.

The socioeconomic study showed that mining provided the major source of income. Over 45% of the households were partly or completely reliant on financial compensations as a result of mine closure. Unemployment was considered by the majority of the interviewed persons as the main cause of social problems in the area. The estimation of the explanatory factors by the logistic regression analysis revealed that education, household income, pollution conditions during the last years and familiarity with environmental problems were the main predictors influencing peoples’ opinion concerning whether the main river is strongly polluted. This model enabled one to predict correctly 77% of the observations reported. For the drinking water quality model, three predictors were relevant and they explained 66% of the observations.

Conclusions

Coupling the findings from the natural science and socioeconomic approaches, we may conclude that the impact of mining on the Certej River water is high, while drinking water in wells is not significantly affected. The perceptions of the respondents to pollution were to a large extent consistent with the measured results.

Recommendations and perspectives

The results of the study can be used by various stakeholders, mainly the mining company and local municipalities, in order to integrate them in their post-mining measures, thereby making them aware of the potential long-term impact of mining on the environment and on human health as well as on the local economy.

     

NMOC,ozone, and organic aerosol in the southeastern United States, 1999–2007: 1. Spatial and temporal variations of NMOC concentrations and composition in Atlanta,Georgia

Volatile organic compounds (VOCs) are emitted from anthropogenic and natural (biogenic) sources into the atmosphere. Characterizing their ambient mixing ratios or concentrations is a challenge because VOCs comprise hundreds of species, and accurate measurements are difficult. Long-term hourly and daily-resolution data have been collected in the metropolitan area of Atlanta, Georgia, a major city dominated by motor vehicle emissions. A series of observations of daily, speciated C₂–C₁₀ non-methane organic compounds (NMOC) and oxygenated hydrocarbons (OVOC) in mid-town Atlanta (Jefferson Street, JST) are compared with data from three urban-suburban sites and a nearby non-urban site. Annual-average mixing ratios of NMOC and OVOC at JST declined from 1999 through 2007. Downward trends in NMOC, CO, and NO_y corroborate expected emission changes as reflected in emission inventories for Atlanta’s Fulton County. Comparison of the JST NMOC composition with data from roadside and tunnel sampling reveals similarities to motor vehicle dominated samples. The JST annual average VOC-OH reactivities from 1999 to 2007 were relatively constant compared with the decline in annual-average NMOC mixing ratios. Mean reactivity at JST, in terms of concentration*k_OH, was approximately 40% alkenes, 22% aromatics, 16% isoprene and 6% other biogenics, 13% C₇–C₁₀ alkanes and 3% C₂-C₆ alkanes, indicating that biogenic NMOCs are important but not dominant contributors to the urban reactive NMOC mix. In contrast, isoprene constituted ～50% of the VOC-OH reactivities at two non-urban sites. Ratios of 24-hour average CO/benzene, CO/isopentane, and CO/acetylene concentrations indicate that such species are relatively conserved, consistent with their low reactivity. Ratios of more-reactive to less-reactive species show diurnal variability largely consistent with expected emission patterns, transport and mixing of air, and chemical processing.     

Study on the threshold relationship between landscape pattern and water quality considering spatial scale effect—a case study of Dianchi Lake Basin in China

Environmental Science and Pollution Research - It is of great significance to analyze the threshold relationship between landscape pattern and water quality for watershed water environment...