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781.
Chloroform is one of the most frequently found anthropogenic groundwater contaminants. Recent investigations, however, suggested
that chloroform in groundwater may also originate from a natural production in soils. As societies response to the occurrence
of chloroform in groundwater may depend upon its origin as anthropogenic or naturally produced, test methods are needed to
measure the potential of natural soil chloroform production. Field measurements of ambient air and soil air, and field and
laboratory incubation studies were evaluated for measurement of relative soil chloroform production at a site with four different
vegetation types (spruce forest, beech forest, grassland, and grain field) on comparable geological soil. All test methods
showed varying soil production of chloroform with spruce forest soil being most productive and grain field soil being least
productive. Field measurements of the ratio of soil air to ambient air chloroform concentrations exhibited the smallest difference
between high production and low production areas, whereas laboratory incubation studies showed the largest difference. Thus,
laboratory incubation studies are suggested as most efficient for estimating relative chloroform production in soil. The study
indicated that soil samples should be tested not more than 14 days after sampling. Furthermore, it was found that potentially
limiting compounds, such as chloride or nitrate, are not needed to be added in spike experiments to obtain reliable production
results. However, it should be recognized that the processes of soil chloroform production are not known yet in all details.
Other factors than those studied here may affect the test methods for soil chloroform production too. 相似文献
782.
Liu C Li L Wang S You X Jiang S Liu F 《Environmental monitoring and assessment》2012,184(7):4247-4251
A simple analytical method was developed to determine the 2,4-D isooctyl ester residue in wheat and soil by gas chromatography coupled with electron capture detector. Using the method, the dissipation and residue of 2,4-D isooctyl ester in wheat field was investigated. The average recoveries of 2,4-D isooctyl ester ranged from 80.1% to 110.0% with relative standard deviations of 2.4% to 16.1%. The pesticide showed a rapid dissipation rate either in wheat seedling or soil, with the half-lives of 1.0 to 3.0 days. The terminal residue results in wheat grain were much lower than the codex MRL (2.0 mg/kg). It could be considered safe to food and environment when using this herbicide for controlling weeds in wheat field. 相似文献
783.
Chiesa M Rigoni F Paderno M Borghetti P Gagliotti G Bertoni M Ballarin Denti A Schiavina L Goldoni A Sangaletti L 《Journal of environmental monitoring : JEM》2012,14(6):1565-1575
The present study is focused on the implementation of a novel, low cost, urban grid of nanostructured chemresistor gas sensors for ammonia concentration ([NH(3)]) monitoring, with NH(3) being one of the main precursors of secondary fine particulate. Low-cost chemresistor gas sensors based on carbon nanotubes have been developed, their response to [NH(3)] in the 0.17-5.0 ppm range has been tested, and the devices have been properly calibrated under different relative humidity conditions in the 33-63% range. In order to improve the chemresistor selectivity towards [NH(3)], an Expert System, based on fuzzy logic and genetic algorithms, has been developed to extract the atmospheric [NH(3)] (with a sensitivity of a few ppb) from the output signal of a model chemresistor gas sensor exposed to an NO(2), NO(X) and O(3) gas mixture. The concentration of these pollutants that are known to be the most significant interfering compounds during ammonia detection with carbon nanotube gas sensors has been tracked by the ARPA monitoring network in the city of Milan and the historical dataset collected over one year has been used to train the Expert System. 相似文献
784.
A 100-year sedimentary record of natural and anthropogenic impacts on a shallow eutrophic lake, Lake Chaohu, China 总被引:6,自引:0,他引:6
Zan F Huo S Xi B Zhu C Liao H Zhang J Yeager KM 《Journal of environmental monitoring : JEM》2012,14(3):804-816
In this study, the sediment profiles of total organic carbon, total nitrogen, C/N ratios, total phosphorus, N/P ratios, C/P ratios, particle sizes, and stable carbon and nitrogen isotopes (δ(13)C and δ(15)N) were used to investigate natural and anthropogenic impacts on Lake Chaohu over the past 100 years. Before 1960, Lake Chaohu experienced low productivity and a relatively steady and low nutrient input. The increasing concentration and fluxes of total organic carbon, total nitrogen, total phosphorus, together with changes in the δ(13)C and δ(15)N of organic material in the sediment cores, suggested that the anthropogenic effects on trophic status first started because of an increase in nutrient input caused by a population increase in the drainage area. With the construction of the Chaohu Dam, an increase in the utilization of fertilizer and the population growth which occurred since 1960, stable depositional conditions and increasing nutrient input resulted in a dominantly algae-derived organic matter source and high productivity. Nutrient input increased most significantly around 1980 following the rapidly growing population, with concomitant urbanization, industrial and agricultural development. This study also revealed that the concentration and distribution of nutrients varied between different areas of sediment within Lake Chaohu because of the influence of different drainage basins and pollution sources. 相似文献
785.
Karagulian F Belis CA Lagler F Barbiere M Gerboles M 《Journal of environmental monitoring : JEM》2012,14(8):2145-2153
Monitoring personal exposure to particle matter (PM(2.5)) in ambient air requires performing measurements using portable monitors. In this work, the portable nephelometer SidePak? AM510 Personal Aerosol Monitor manufactured by TSI Inc. was evaluated against a Tapered Element Oscillating Microbalance (TEOM) equipped with a Filter Dynamics Measurements System (FDMS). Conventionally, the SidePak is calibrated with respect to the Arizona Road Test Dust and then multiplied by an environmental calibration factor to yield mass concentration. To adapt this calibration to specific field conditions, we present an implementation of this calibration by introducing a growing factor correction which takes into account relative humidity and the dry and wet portions of the refractive index estimated from TEOM-FDMS measurements. PM(2.5) sampling with several SidePaks AM510 was carried out in background and rural sites in the Po Valley (Italy). Modeled SidePak data were plotted vs. reference TEOM-FDMS data which show a good agreement. 相似文献
786.
IA Fioravante B Albergaria TS Teodoro SM Starling Magalhães F Barbosa R Augusti 《Journal of environmental monitoring : JEM》2012,14(9):2362-2366
An unprecedented investigation dealing with the removal of 17α-ethinylestradiol (EE2, a contraceptive hormone) by the cyanobacteria Microcystis novacekii (a species that is abundant and easily accessible in Brazilian lakes) from a sterile WC medium is described herein. The results indicated that whereas EE2 experienced insignificant spontaneous degradation, Microcystis novacekii was capable of removing ca. 65% of the hormone from the culture medium. Furthermore, no metabolites were detected at the concentration levels evaluated (0.10 to 0.17 mg L(-1)) as verified by the use of GC-MS, a quite sensitive analytical technique, and adequate pre-concentration procedures (SPME and liquid extraction). Elucidative experiments, including an appropriate cell lyses procedure, indicated that EE2 was likely accumulated within the cells (bioaccumulation) rather than adsorbed on the cellular membrane (biosorption). Moreover, the intra- and extracellular contents of EE2 were shown to be roughly complementary. Finally, the species was found to be highly tolerant to the hormone as its growth rates were higher in the test than in the control experiments. All these findings, therefore, point to the use of Microcystis novacekii as a potential agent to treat effluents contaminated with EE2. 相似文献
787.
Rodrigues S Antunes SC Brandão FP Castro BB Gonçalves F Nunes B 《Journal of environmental monitoring : JEM》2012,14(6):1638-1644
The presence of pharmaceutical residues in the aquatic environment has recently received great attention, as potential adverse effects may arise from their presence. Inhibition of cholinesterases (ChE) has been widely used as an environmental biomarker of exposure to organophosphates (OP) and carbamate (CB) pesticides. However, other widespread anthropogenic contaminants - including pharmaceutical drugs - can exert toxic effects through ChE inhibition. Studies with aquatic species have shown that inhibition of ChE is associated with behavioral changes. Bearing this in mind, this work aimed to study the effects on individual behavior and acetylcholinesterase (AChE) activity of selected tissues of Lepomis gibbosus, after exposure to the anticholinesterasic drugs neostigmine and pyridostigmine. Results revealed that neostigmine significantly decreased the activity of AChE in the head (LOEC = 100 mg L(-1)), but not in dorsal muscle. On the other hand, pyridostigmine significantly decreased the activity of AChE in both the head (LOEC = 0.001 mg L(-1)) and dorsal muscle homogenates (LOEC = 100 mg L(-1)). The impairment of this enzymatic form was attained at ecologically relevant concentrations (in the case of pyridostigmine, for head AChE), which is an interesting finding, specially considering that these toxic effects occurred for a pharmaceutical compound. Contrarily, there were no significant differences in the behavior of L. gibbosus in any parameter, for neither drug. These results suggest that the behavioral parameters analyzed (scototaxis and lethargy) in L. gibbosus could not be regarded as suitable markers to assess the effects of drugs such as neostigmine and pyridostigmine. In contrast, the pattern of response elicited by cholinesterasic inhibition showed the usefulness of this toxicological parameter for the assessment of pharmaceuticals in the environment, namely anticholinesterasics. 相似文献
788.
The purpose of this study was to predict quantitative changes in evaporation from bare soils in the Mediterranean climate
region of Turkey in response to the projections of a regional climate model developed in Japan (hereafter RCM). Daily RCM
data for the estimation of reference evapotranspiration (ET
r) and soil evaporation were obtained for the periods of 1994–2003 and 2070–2079. Potential evaporation (E
p) from bare soils was calculated using the Penman–Monteith equation with a surface resistance of zero. Simulation of actual
soil evaporation (E
a) was carried out using Aydin model (Aydin et al., Ecological Modelling 182:91–105, 2005) combined with Aydin and Uygur (2006,
A model for estimating soil water potential of bare fields. In Proceedings of the 18th International Soil Meeting (ISM) on Soils Sustaining Life on Earth, Managing Soil and Technology,
Sanliurfa, 477–480pp.) model of predicting soil water potential at the top surface layer of a bare soil, after performances of Aydin
model (R
2 = 94.0%) and Aydin and Uygur model (R
2 = 97.6) were tested. The latter model is based on the relations among potential soil evaporation, hydraulic diffusivity,
and soil wetness, with some simplified assumptions. Input parameters of the model are simple and easily obtainable such as
climatic parameters used to compute the potential soil evaporation, average diffusivity for the drying soil, and volumetric
water content at field capacity. The combination of Aydin and Aydin and Uygur models appeared to be useful in estimating water
potential of soils and E
a from bare soils, with only a few parameters. Unlike ET
r and E
p projected to increase by 92 and 69 mm (equivalent to 8.0 and 7.3% increases) due to the elevated evaporative demand of the
atmosphere, respectively, E
a from bare soils is projected to reduce by 50 mm (equivalent to a 16.5% decrease) in response to a decrease in rainfall by
46% in the Mediterranean region of Turkey by the 2070s predicted by RCM, and consequently, to decreased soil wetness in the
future. 相似文献
789.
Arkian F Salahinejad M Bidokhti AA Meshkatee A 《Environmental monitoring and assessment》2008,140(1-3):325-330
Measurement of gross α, gross β activities and cosmogenic beryllium-7 (7Be) concentrations were made both daily and weekly during the years 2001–2004 from samples of atmospheric aerosols filtered
from the air at Tehran Nuclear Research Center (35 41′ N) and Zahedan (28 29′ N). Weekly aerosol samples collected with the
high-volume air samplers on cellulose filters were used to determine the 7Be contents of samples, using a semiconductor gamma spectrometer. Airborne dust samples were collected daily on fiber glass
filters and used to determine the gross β and gross α activities with automatic beta analyzer and a ZnS(Ag) counter, respectively.
In this work, the concentration and meteorological data were used to determine models for gross α, gross β and 7Be. The air concentrations of gross β and gross α activities and 7Be concentrations displayed lognormal distributions during the study period. Both β and 7Be have maximum activity concentrations during warm mid-year months. 相似文献
790.
Demirkesen AC Evrendilek F Berberoglu S 《Environmental monitoring and assessment》2008,138(1-3):101-106
The vulnerability of low-lying coastal areas in Turkey to inundation was quantified based on the sea-level rise scenarios
of 1, 2, and 3 m by 2205. Through digital elevation model (DEM) acquired by the shuttle radar topography mission (SRTM), the
extent and distribution of the high to low-risk coastal plains were identified. The spatio-temporal analysis revealed the
inundated coastal areas of 545, 1,286, and 2,125 km2 at average rates of 5, 10, and 15 mm yr−1 for 200 years, respectively. This is equivalent to minimum and maximum land losses by 2205 of 0.1–0.3% of the total area
and of 1.3–5.2% of the coastal areas with elevations of less than 100 m in the country, respectively. This study provides
an initial assessment of vulnerability to sea-level rise to help decision-makers, and other concerned stakeholders to develop
appropriate public policies and land-use planning measures. 相似文献