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211.
Wigand C McKinney RA Cole ML Thursby GB Cummings J 《Environmental monitoring and assessment》2007,131(1-3):71-81
The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this
study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ
15N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ
15N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ
15N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ
15N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas,
the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ
15N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R
2 = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ
15N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ
15N of Spartina relates with the integrated, watershed-sea nitrogen inputs. 相似文献
212.
Yannopoulos PC 《Environmental monitoring and assessment》2007,135(1-3):163-180
An economic and quick methodology for performing a preliminary spatial assessment of a city air quality with the purpose to
identify locations and zones susceptible to high pollution levels is proposed. A Patras case-study is selected, regarding
the air pollutants of sulfur dioxide (SO2) and oxides of nitrogen (NOx). A total number of 451 samples of short duration, of which 225 were randomly picked in morning rush hours and 226 within
evening rush hours, were collected from 50 locations of the major Patras area during a year period, when peaks of primary
air pollutants usually occur. Concentration measurements at prescribed locations used to statistically calculate spatial average
concentrations approximating 1-h mean values with mean probable errors less than 25.9% for SO2, NO and NOx and less than 15.5% for NO2. Then iso-concentration contour diagrams plotted indicate high pollution zones and possibly appropriate locations for continuous
or random monitoring according to the European Community (EC) Directives. The 1-h mean concentrations were in good correlation
to the corresponding traffic rates and useful relationships are given (0.54 ≤ r ≤ 0.63). In addition, comparisons with data available for other cities, as well as with the limit and guide values provided
by the EC and the World Health Organization (WHO) were given. The present data could be useful for the design and optimization
of a city network of stations for monitoring air quality, for environmental impact assessments, future reference and comparisons
due to city development needs, as well as for validating dispersion models. 相似文献
213.
Inamdar S 《Environmental monitoring and assessment》2007,133(1-3):347-363
Storm event exports of dissolved were explored for multiple events in the Point Peter Brook watershed (PPBW), a glaciated, forested watershed located in Western
New York, USA. Investigations were performed across four catchments (1.6–696 ha) with varying topography and the extent of
surface-saturated areas. While wetland and riparian waters were important sources of during non-storm periods, throughfall and litter leachate were the dominant contributors of during storm events. Ammonium concentrations in catchment discharge displayed a sinusoidal seasonal pattern with a maximum
during early spring (March) and a minimum in late summer (August–September). Storm event concentrations of in streamflow were much greater than baseflow values and showed a consistent temporal pattern with an increase in concentrations
on the hydrograph rising limb, a peak at or before the discharge peak, followed by a decline in concentrations. Storm event
patterns of DON were similar to while the patterns of differed from for the summer and fall events. The storm event expression of was attributed to throughfall and throughfall-mediated leaching of the litter layer. The reactive behavior of precluded its use in an end member mixing model (EMMA) for predicting streamflow concentrations. While concentrations of
in precipitation and streamflow were high for the spring events, exports of in streamflow were highest for the large and intense storm events. Baseflow concentrations increased with the percent wetland/saturated area in the catchment but the same trend did not hold for storm-event
concentrations. 相似文献
214.
Evaluation of surface runoff and road dust as sources of nitrogen using nitrate isotopic composition 总被引:1,自引:0,他引:1
Stable nitrogen and oxygen isotope ratios of nitrate (δ15N-NO3 and δ18O-NO3) have recently been used to identify nitrogen sources in water environments. However, there have been no investigations designed to determine nitrate isotopes in non-point sources in urban areas for evaluating the impact of surface deposits on nitrogen in surface runoff. In this study, we collected rainwater, surface runoff and surface deposits (road dust, roof dust and soil) to evaluate the nitrogen sources in surface runoff using nitrate isotopes. There were no large differences in δ15N-NO3 among rainwater (−0.3‰ to 1.5‰), surface runoff (−2.7‰ to 0.4‰), leachates from road dust (−5.8‰ to 6.2‰) and soil (−11.5‰ to 0.6‰). In contrast, the δ18O-NO3 in surface runoff (28.5-47.9‰) was lower than that in rainwater (62.7-78.6‰), and higher than that in leachates from road dust (6.1-27.6‰) and soil (−1.1‰ to 6.6‰). δ18O-NO3 is a useful indicator for evaluating the NO3-N sources in surface runoff. Using this indicator, NO3-N from road dust was estimated to account for more than half of the NO3-N in surface runoff. This is consistent with a result based on a comparison of their loads per unit surface between rainwater and surface runoff, which also showed that most of the nitrogen in surface runoff was derived from surface deposits. 相似文献
215.
The role of nitrogen (N) in acidification of soil and water has become relatively more important as the deposition of sulphur has decreased. Starting in 1991, we have conducted a whole-catchment experiment with N addition at Gårdsjön, Sweden, to investigate the risk of N saturation. We have added 41 kg N ha−1 yr−1 as NH4NO3 to the ambient 9 kg N ha−1 yr−1 in fortnightly doses by means of sprinkling system. The fraction of input N lost to runoff has increased from 0% to 10%. Increased concentrations of NO3 in runoff partially offset the decreasing concentrations of SO4 and slowed ecosystem recovery from acid deposition. From 1990-2002, about 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. The soil N pool increased by 5%. N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g−1. 相似文献
216.
Sanz J Bermejo V Muntifering R González-Fernández I Gimeno BS Elvira S Alonso R 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):423-430
An assessment of the effects of tropospheric ozone (O3) levels and substrate nitrogen (N) supplementation, singly and in combination, on phenology, growth and nutritive quality of Briza maxima was carried out. Two serial experiments were developed in Open-Top Chambers (OTC) using three O3 and three N levels. Increased O3 exposure did not affect the biomass-related parameters, but enhanced senescence, increased fiber foliar content (especially lignin concentration) and reduced plant life span; these effects were related to senescence acceleration induced by the pollutant. Added N increased plant biomass production and improved nutritive quality by decreasing foliar fiber concentration. Interestingly, the effects of N supplementation depended on meteorological conditions and plant physiological activity. N supplementation counteracted the O3-induced senescence but did not modifiy the effects on nutritive quality. Nutritive quality and phenology should be considered in new definitions of the O3 limits for the protection of herbaceous vegetation. 相似文献
217.
Rivera M Zechmeister H Medina-Ramón M Basagaña X Foraster M Bouso L Moreno T Solanas P Ramos R Köllensperger G Deltell A Vizcaya D Künzli N 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):954-962
One monitoring station is insufficient to characterize the high spatial variation of traffic-related heavy metals within cities. We tested moss bags (Hylocomium splendens), deployed in a dense network, for the monitoring of metals in outdoor air and characterized metals’ long-term spatial distribution and its determinants in Girona, Spain. Mosses were exposed outside 23 homes for two months; NO2 was monitored for comparison. Metals were not highly correlated with NO2 and showed higher spatial variation than NO2. Regression models explained 61-85% of Cu, Cr, Mo, Pb, Sb, Sn, and Zn and 72% of NO2 variability. Metals were strongly associated with the number of bus lines in the nearest street. Heavy metals are an alternative traffic-marker to NO2 given their toxicological relevance, stronger association with local traffic and higher spatial variability. Monitoring heavy metals with mosses is appealing, particularly for long-term exposure assessment, as mosses can remain on site many months without maintenance. 相似文献
218.
Harmens H Norris DA Cooper DM Mills G Steinnes E Kubin E Thöni L Aboal JR Alber R Carballeira A Coşkun M De Temmerman L Frolova M González-Miqueo L Jeran Z Leblond S Liiv S Maňkovská B Pesch R Poikolainen J Rühling A Santamaria JM Simonèiè P Schröder W Suchara I Yurukova L Zechmeister HG 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2852-2860
In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations (≥1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km × 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. 相似文献
219.
Raysoni AU Sarnat JA Sarnat SE Garcia JH Holguin F Luèvano SF Li WW 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2476-2486
Paired indoor and outdoor concentrations of fine and coarse particulate matter (PM), PM2.5 reflectance [black carbon(BC)], and nitrogen dioxide (NO2) were determined for sixteen weeks in 2008 at four elementary schools (two in high and two in low traffic density zones) in a U.S.-Mexico border community to aid a binational health effects study. Strong spatial heterogeneity was observed for all outdoor pollutant concentrations. Concentrations of all pollutants, except coarse PM, were higher in high traffic zones than in the respective low traffic zones. Black carbon and NO2 appear to be better traffic indicators than fine PM. Indoor air pollution was found to be well associated with outdoor air pollution, although differences existed due to uncontrollable factors involving student activities and building/ventilation configurations. Results of this study indicate substantial spatial variability of pollutants in the region, suggesting that children’s exposures to these pollutants vary based on the location of their school. 相似文献
220.