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751.
Sutton MA Nemitz E Erisman JW Beier C Bahl KB Cellier P de Vries W Cotrufo F Skiba U Di Marco C Jones S Laville P Soussana JF Loubet B Twigg M Famulari D Whitehead J Gallagher MW Neftel A Flechard CR Herrmann B Calanca PL Schjoerring JK Daemmgen U Horvath L Tang YS Emmett BA Tietema A Peñuelas J Kesik M Brueggemann N Pilegaard K Vesala T Campbell CL Olesen JE Dragosits U Theobald MR Levy P Mobbs DC Milne R Viovy N Vuichard N Smith JU Smith P Bergamaschi P Fowler D Reis S 《Environmental pollution (Barking, Essex : 1987)》2007,150(1):125-139
Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols. 相似文献
752.
Mayer T Bennie D Rosa F Rekas G Palabrica V Schachtschneider J 《Environmental pollution (Barking, Essex : 1987)》2007,147(3):683-690
Occurrence and fate of alkylphenols (APs), known endocrine disruptors, were investigated in a Great Lakes coastal wetland, Cootes Paradise, ON. The wetland, which receives discharges from a Wastewater Treatment Plant (WTP) and several Combined Sewer Overflows (CSOs), is an important spawning ground for fish and crucial habitat for other fauna. Elevated concentrations of nonylphenol ethoxylates (NPEs) and their degradation product nonylphenol (NP) were found in water and sediment samples near the sources. Since transfer of APs through the food chain is of concern, we compared their concentrations in invertebrates from clean and contaminated sites. The results reveal transfer of alkylphenolics from sediments to biota and their accumulation in the invertebrate tissue, particularly the highly hydrophobic 4-NP, whose concentrations ranged from 1.9 to 6.3 microg g(-1). To our knowledge, this is the first study to evaluate AP concentrations in tissue of benthic invertebrates under real environmental conditions. 相似文献
753.
Jaji MO Bamgbose O Odukoya OO Arowolo TA 《Environmental monitoring and assessment》2007,133(1-3):473-482
The quality of Ogun river in South-West, Nigeria was studied by a field survey for a period of 1 year (covering dry season
and rainy season). Water samples were collected from thirteen sites and analysed for physico-chemical and bacteriological
parameters as well as heavy metals using standard methods. Generally, the values obtained for turbidity, phosphate, oil and
grease, iron and faecal coliform from all the sites in both seasons were above the maximum acceptable limit set by the World
Health Organization (WHO) for drinking water. Also, the manganese content from all the sites in the dry season, lead concentrations
from three sites in the dry season and cadmium concentrations from some sites in both seasons were above the WHO limit. The
values obtained for total dissolved solids, dissolved oxygen and chloride at site M in the dry season and nitrate at site
J in the rainy season were also above the WHO limit. Pollution of Ogun river water along its course is evidenced by the high
concentrations of pollution indicators, nutrients and trace metals above the acceptable limit. This poses a health risk to
several rural communities who rely on the river primarily as their source of domestic water. The study showed a need for continuous
pollution monitoring programme of surface waters in Nigeria. 相似文献
754.
Wetherbee GA Gay DA Brunette RC Sweet CW 《Environmental monitoring and assessment》2007,131(1-3):49-69
The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of
mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification
of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in
two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury
concentration are approximately 11% of the median mercury concentration for all valid 1999–2004 MDN data. Median absolute
differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15%
of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between
NADP/MDN measurements by ±2 ng·l−1 and ±2 μg·m−2·year−1, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively. 相似文献
755.
Libby, Montana is the only PM2.5 nonattainment area in the western United States with the exceptions of parts of southern California. During January through
March 2005, a particulate matter (PM) sampling program was conducted within Libby’s elementary and middle schools to establish
baseline indoor PM concentrations before a wood stove change-out program is implemented over the next several years. As part
of this program, indoor concentrations of PM mass, organic carbon (OC), and elemental carbon (EC) in five different size fractions
(>2.5, 1.0–2.5, 0.5–1.0, 0.25–0.5, and <0.25 μm) were measured. Total measured PM mass concentrations were much higher inside
the elementary school, with particle size fraction (>2.5, 0.5–1.0, 0.25–0.5, and <0.25 μm) concentrations between 2 and 5
times higher when compared to the middle school. The 1.0–2.5 μm fraction had the largest difference between the two sites,
with elementary school concentrations nearly 10 times higher than the middle school values. The carbon component for the schools’
indoor PM was found to be predominantly composed of OC. Measured total OC and EC concentrations, as well as concentrations
within individual size fractions, were an average of two to five times higher at the elementary school when compared to the
middle school. For the ultrafine fraction (<0.25), EC concentrations were similar between each of the schools. Despite the
differences in concentrations between the schools at the various fraction levels, the OC/EC ratio was determined to be similar. 相似文献
756.
Recent research has shown that carbonaceous solid materials and zerovalent iron (Fe(0)) may potentially be used as media in permeable reactive barriers (PRBs) to degrade groundwater nitrate via heterotrophic denitrification in the solid carbon system, and via abiotic reduction and autotrophic denitrification in the Fe(0) system. Questions arise as whether the more expensive Fe(0) is more effective than the less expensive carbonaceous solid materials for groundwater nitrate remediation, and whether there is any synergistic effect of mixing the two different types of materials. We carried out batch tests to study the nature and rates of removal of added nitrate in the suspensions of single, binary, and ternary systems of cotton burr compost, Peerless Fe(0), and a sediment low in organic carbon. Cotton burr compost acted as both organic carbon source and supporting material for the growth of indigenous denitrifiers. Batch tests showed that cotton burr compost alone removed added nitrate at a greater rate than did Peerless Fe(0) alone on an equal mass basis with a pseudo-first-order rate constant k=0.0830+/-0.0031 h(-1) for cotton burr compost and a k=0.00223+/-0.00022 h(-1) for Peerless Fe(0); cotton burr compost also removed added nitrate at a faster rate than did cotton burr compost mixed with Peerless Fe(0) and/or the sediment. Furthermore, there was no substantial accumulation of ammonium ions in the cotton burr compost system, in contrast to the systems containing Peerless Fe(0) in which ammonium ions persisted as major products of nitrate reduction. It is concluded that cotton burr compost alone may be used as an excellent denitrification medium in a PRB for groundwater nitrate removal. Further study is needed to evaluate performance of its field applications. 相似文献
757.
Kröger R Holland MM Moore MT Cooper CM 《Environmental pollution (Barking, Essex : 1987)》2007,146(1):114-119
The beneficial uptake of nutrients by wetland plants is countered to some extent by nutrient release back into the aquatic environment due to vegetative die-back. This current study examined whether Leersia oryzoides, a common wetland plant, exhibits luxury uptake of nutrients from simulated farm runoff. The study also tested whether with subsequent decomposition, these nutrients are released back into the water column. When exposed to elevated (>2mg/L N and P) runoff, L. oryzoides assimilated significantly higher concentrations of nitrogen (p<0.001) and phosphorus (p<0.001) in above-ground biomass as compared to non-enriched treatments (<0.05 mg/L N and P). Subsequently, senescence of enriched above-ground biomass yielded significantly higher concentrations of phosphorus (2.19+/-0.84 mg P/L). Using L. oryzoides as our model, this study demonstrates nitrogen and phosphorus sequestration during the growing season and release of phosphorus in the winter. 相似文献
758.
Essential and non-essential element concentrations in two sleeper shark species collected in arctic waters 总被引:1,自引:0,他引:1
McMeans BC Borgå K Bechtol WR Higginbotham D Fisk AT 《Environmental pollution (Barking, Essex : 1987)》2007,148(1):281-290
A number of elements/metals have increased in arctic biota and are of concern due to their potential toxicity. Most studies on elements in the Arctic have focused on marine mammals and seabirds, but concentrations in the Greenland shark (Somniosus microcephalus) and Pacific sleeper shark (Somniosus pacificus), the only two shark species known to regularly inhabit arctic waters, have never been reported. To address this data gap, concentrations and patterns of 25 elements were analyzed in liver of Greenland sharks collected about Cumberland Sound (n=24) and Pacific sleeper sharks collected about Prince William Sound (n=14). Several non-essential elements differed between species/locations, which could suggest geographical exposure differences or ecological (e.g., diet) differences between the species. Certain essential elements also differed between the two sleeper sharks, which may indicate different physiological requirements between these closely related shark species, although information on such relationships are lacking for sharks and fish. 相似文献
759.
Allen YT Thain JE Haworth S Barry J 《Environmental pollution (Barking, Essex : 1987)》2007,146(1):92-99
Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required. 相似文献
760.
Differential responses of the freshwater wetland species Juncus effusus L. and Caltha palustris L. to iron supply in sulfidic environments 总被引:1,自引:0,他引:1
Van der Welle ME Niggebrugge K Lamers LP Roelofs JG 《Environmental pollution (Barking, Essex : 1987)》2007,147(1):222-230
Sulfur pollution can lead to serious problems in freshwater wetlands, including phosphorus eutrophication and sulfide toxicity. We tested the effects of anaerobic iron-rich groundwater discharge in fens, simulated by iron injection, on two characteristic species (Juncus effusus and Caltha palustris) in a sulfidic environment. Biomass production of C. palustris roots showed an optimum response to the combined addition of iron and sulfide, with highest values at intermediate concentrations of both substances. Iron deficiency apparently occurred at low iron concentrations, while at high iron concentrations, growth was decreased. For J. effusus, in contrast, no toxic effects were found of both iron and sulfide. This could be explained by larger radial oxygen loss (ROL) of J. effusus and could not be explained by differences in phosphorous concentrations. The results of our experiments confirm that iron-rich groundwater discharge has the potential to affect vegetation composition through toxicity modification in sulfidic environments. 相似文献