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841.
Temporal evolution in PPCP removal from urban wastewater by constructed wetlands of different configuration: a medium-term study 总被引:1,自引:0,他引:1
Reyes-Contreras C Hijosa-Valsero M Sidrach-Cardona R Bayona JM Bécares E 《Chemosphere》2012,88(2):161-167
Pharmaceuticals and personal care products (PPCPs) are widely distributed in urban wastewaters and can be removed to some extent by constructed wetlands (CWs). The medium-term (3-5 years) behaviour of these systems regarding PPCP removal is still unknown. Seven mesocosm-scale (1 m2) CWs of different configurations were operated outdoors for 39 months under the same conditions to assess their PPCP removal ability and temporal evolution. CWs differed in some design parameters, namely plant presence, species chosen (Typha angustifolia vs Phragmites australis), flow configuration and presence/absence of gravel bed (floating macrophytes surface flow, FM-SF; free-water surface flow, FW-SF; free-water subsurface flow, FW-SSF; or conventional horizontal subsurface flow, SSF). PPCP efficiencies decreased throughout time and performance differences among CWs disappeared with the systems aging. This could be due to a homogenization process in the systems caused by detrimental factors like saturation, clogging and shading. Winter efficiencies were lower than summer ones for salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide, and seasonal biological activities seem key factors to explain this fact. Maximal removal efficiencies were achieved in an unplanted-FW-SSF for ketoprofen (47-81%), naproxen (58-81%) and salicylic acid (76-98%); in an unplanted-SSF for caffeine (65-99%); in a Phragmites-FM-SF for ibuprofen (49-96%) and diclofenac (16-68%); in a Typha-FM-SF for carbamazepine (35-71%); and in a Typha-FW-SSF for methyl dihydrojasmonate (71-96%), galaxolide (67-82%) and tonalide (55-74%). Photodegradation could be involved in ketoprofen, naproxen, ibuprofen and diclofenac removal. Carbamazepine and diclofenac were moderately removed by the most efficient CWs studied. Carbamazepine might be eliminated by vegetal uptake. 相似文献
842.
S. R. Silva P. B. Ging R. W. Lee J. C. Ebbert A. J. Tesoriero E. L. Inkpen 《Environmental Forensics》2013,14(2):125-130
Ground and surface waters in urban areas are susceptible to nitrate contamination from septic systems, leaking sewer lines, and fertilizer applications. Source identification is a primary step toward a successful remediation plan in affected areas. In this respect, nitrogen and oxygen isotope ratios of nitrate, in conjunction with hydrologic data and water chemistry, have proven valuable in urban studies from Austin, Texas, and Tacoma, Washington. In Austin, stream water was sampled during stremflow and baseflow conditions to assess surface and subsurface sources of nitrate, respectively. In Tacoma, well waters were sampled in adjacent sewered and un-sewered areas to determine if locally high nitrate concentrations were caused by septic systems in the un-sewered areas. In both studies, sewage was identified as a nitrate source and mixing between sewage and other sources of nitrate was apparent. In addition to source identification, combined nitrogen and oxygen isotopes were important in determining the significance of denitrification, which can complicate source assessment by reducing nitrate concentrations and increasing i 15 N values. The two studies illustrate the value of nitrogen and oxygen isotopes of nitrate for forensic applications in urba areas. 相似文献
843.
Musa Bandowe BA Sobocka J Wilcke W 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):539-549
We determined concentrations, sources, and vertical distribution of OPAHs and PAHs in soils of Bratislava. The ∑14 OPAHs concentrations in surface soil horizons ranged 88-2692 ng g−1 and those of ∑34 PAHs 842-244,870 ng g−1. The concentrations of the ∑9 carbonyl-OPAHs (r = 0.92, p = 0.0001) and the ∑5 hydroxyl-OPAHs (r = 0.73, p = 0.01) correlated significantly with ∑34 PAHs concentrations indicating the close association of OPAHs with parent-PAHs. OPAHs were quantitatively dominated by 9-fluorenone, 9,10-anthraquinone, 1-indanone and benzo[a]anthracene-7,12-dione. At several sites, individual carbonyl-OPAHs had higher concentrations than parent PAHs. The concentration ratios of several OPAHs to their parent-PAHs and contribution of the more soluble OPAHs (1-indanone and 9-fluorenone) to ∑14 OPAHs concentrations increased with soil depth suggesting that OPAHs were faster vertically transported in the study soils by leaching than PAHs which was supported by the correlation of subsoil:surface soil ratios of OPAH concentrations at several sites with KOW. 相似文献
844.
The variability of polychlorinated biphenyls levels in urban soils from five European cities 总被引:3,自引:0,他引:3
Cachada A Lopes LV Hursthouse AS Biasioli M Grcman H Otabbong E Davidson CM Duarte AC 《Environmental pollution (Barking, Essex : 1987)》2009,157(2):511-518
The concentration of PCBs in topsoils from five European cities was assessed and the highest levels were found in Glasgow (Scotland), followed by Torino (Italy), Aveiro (Portugal), Ljubljana (Slovenia) and Uppsala (Sweden). All cities showed the presence of local sources in addition to diffuse contamination from global atmospheric transport. The association of general soil parameters with PCBs in Glasgow and with heavier congeners in Torino and Ljubljana indicates that retention of these compounds is occurring. The profiles obtained resemble Aroclor 1254 and 1260, which are important local sources. Nevertheless, differences in PCB profiles were observed among cities, due to the combined effects of the age of the contamination (which determines the time available for volatilisation and degradation), different sources of PCBs and differences in climate (which influence volatilisation and deposition). 相似文献
845.
Long-Term Effects of Changing Land Use Practices on Surface Water Quality in a Coastal River and Lagoonal Estuary 总被引:1,自引:0,他引:1
Meghan B. Rothenberger JoAnn M. Burkholder Cavell Brownie 《Environmental management》2009,44(3):505-523
The watershed of the Neuse River, a major tributary of the largest lagoonal estuary on the U.S. mainland, has sustained rapid
growth of human and swine populations. This study integrated a decade of available land cover and water quality data to examine
relationships between land use changes and surface water quality. Geographic Information Systems (GIS) analysis was used to
characterize 26 subbasins throughout the watershed for changes in land use during 1992–2001, considering urban, agricultural
(cropland, animal as pasture, and densities of confined animal feed operations [CAFOs]), forested, grassland, and wetland
categories and numbers of wastewater treatment plants (WWTPs). GIS was also used together with longitudinal regression analysis
to identify specific land use characteristics that influenced surface water quality. Total phosphorus concentrations were
significantly higher during summer in subbasins with high densities of WWTPs and CAFOs. Nitrate was significantly higher during
winter in subbasins with high numbers of WWTPs, and organic nitrogen was higher in subbasins with higher agricultural coverage,
especially with high coverage of pastures fertilized with animal manure. Ammonium concentrations were elevated after high
precipitation. Overall, wastewater discharges in the upper, increasingly urbanized Neuse basin and intensive swine agriculture
in the lower basin have been the highest contributors of nitrogen and phosphorus to receiving surface waters. Although nonpoint
sources have been emphasized in the eutrophication of rivers and estuaries such as the Neuse, point sources continue to be
major nutrient contributors in watersheds sustaining increasing human population growth. The described correlation and regression
analyses represent a rapid, reliable method to relate land use patterns to water quality, and they can be adapted to watersheds
in any region. 相似文献
846.
Effects of Increasing Urbanization on the Ecological Integrity of Open Space Preserves 总被引:3,自引:0,他引:3
This article analyzes the effects of increasing urbanization on open space preserves within the metropolitan area of Phoenix,
Arizona, USA. Time series analysis is used in 10-year increments over 40 years to study urban landscape change. Three landscape
metrics—(1) matrix utility (measures intensity of adjacent land uses), (2) isolation (measures distances to other open space
patches), and (3) connectivity (measures physical links to other open space patches and corridors)—are used to assess changes
in landscape patterns and serve as indicators of urban ecological integrity of the open space preserves. Results show that
in the case of both open space preserves, general decline in indicators of urban ecological integrity was evident. The matrix
utility analysis demonstrated that increasing intensity of land uses adjacent to preserve is likely to increase edge effects,
reducing the habitat value of interior or core habitat areas. Isolation analysis showed that both preserves have experienced
increasing isolation from other open space elements over time. Also, connectivity analysis indicated that terrestrial connections
to other open space elements have also deteriorated. Conclusions of this research demonstrate that while preservation of natural
areas as open space is important in an urban context, intense development of surrounding areas reduces the urban ecological
integrity significantly. 相似文献
847.
Zambrano L Contreras V Mazari-Hiriart M Zarco-Arista AE 《Environmental management》2009,43(2):249-263
Awareness of environmental heterogeneity in ecosystems is critical for management and conservation. We used the Xochimilco
freshwater system to describe the relationship between heterogeneity and human activities. This tropical aquatic ecosystem
south of Mexico City is comprised of a network of interconnected canals and lakes that are influenced by agricultural and
urban activities. Environmental heterogeneity was characterized by spatially extensive surveys within four regions of Xochimilco
during rainy and dry seasons over 2 years. These surveys revealed a heterogeneous system that was shallow (1.1 m, SD = 0.4 ),
warm (17°C, SD = 2.9), well oxygenated (5.0 mg l−1, SD = 3), turbid (45.7 NTU SD = 26.96), and extremely nutrient-rich (NO3–N = 15.9 mg l−1, SD=13.7; NH4–N = 2.88 mg l−1, SD = 4.24; and PO4–P = 8.3 mg l−1, SD = 2.4). Most of the variables were not significantly different between years, but did differ between seasons, suggesting
a dynamic system within a span of a year but with a high resilience over longer periods of time. Maps were produced using
interpolations to describe distributions of all variables. There was no correlation between individual variables and land
use. Consequently, we searched for relationships using all variables together by generating a combined water quality index.
Significant differences in the index were apparent among the four regions. Index values also differed within individual region
and individual water bodies (e.g., within canals), indicating that Xochimilco has high local heterogeneity. Using this index
on a map helped to relate water quality to human activities and provides a simple and clear tool for managers and policymakers. 相似文献
848.
以高投入、高消耗、高产出和高排放为特征的都市现代农业,对环境具有更大、更直接的影响,但只要选择恰当的模式,都市现代农业能够与环境实现协调发展。本文总结了成都市几种环境友好型现代农业发展模式,提出了促进环境与现代农业进一步协调的途径与对策,对全国的都市农业的发展有参考价值。 相似文献
849.
Ajmone-Marsan F Biasioli M Kralj T Grcman H Davidson CM Hursthouse AS Madrid L Rodrigues S 《Environmental pollution (Barking, Essex : 1987)》2008,152(1):73-81
Soils from Aveiro, Glasgow, Ljubljana, Sevilla and Torino have been investigated in view of their potential for translocation of potentially toxic elements (PTE) to the atmosphere. Soils were partitioned into five size fractions and Cr, Cu, Ni, Pb and Zn were measured in the fractions and the whole soil. All PTE concentrated in the <10 microm fraction. Cr and Ni concentrated also in the coarse fraction, indicating a lithogenic contribution. An accumulation factor (AF) was calculated for the <2 and <10 microm fraction. The AF values indicate that the accumulation in the finer fractions is higher where the overall contamination is lower. AF for Cr and Ni are particularly low in Glasgow and Torino. An inverse relationship was found between the AF of some metals and the percentage of <10 microm particles that could be of use in risk assessment or remediation practices. 相似文献
850.
The SoftGIS approach to local knowledge 总被引:2,自引:0,他引:2
The aim of the SoftGIS approach is to support urban planning processes and decision-making. SoftGIS aims to present a more comprehensive understanding of local knowledge. This is realized by the mapping of local knowledge and its integration into urban planning practices. SoftGIS is a multidisciplinary approach where different Internet- and GIS-based methods are developed to gather and process local knowledge. In this article we present the theoretical background to the SoftGIS approach as well as two case studies. 相似文献