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1.
Abstract

Sheep metabolized a single oral dose of 2‐chloro‐N‐isopro‐pylacetanilide (propachlor) to four urinary metabolites. These were 2‐(S‐cysteinyl)‐N‐isopropylacetanilide and 2‐[S‐(N‐acetyl) cysteinyl]‐N‐isopropylacetanilide and the glucuronide conjugates of 4'‐hydroxy‐N‐isopropyl‐2‐methylsulfonylacetanilide and N‐(1‐hydroxyisopropyl)‐2‐methylsulfonylacetanilide. Residues (ppb equivalents of propachlor) from [14C]‐propachlor in the milk from a goat given daily oral doses (1.3 mg of propachlor three times daily for 15 days) plateaued at about 2 to 4 ppb equivalents of propachlor. In goat tissue, residues ranged from 1 ppb (fat) to 20 ppb (liver). Fecal and tissue metabolites were not identified.  相似文献   

2.
A self-consistent expression for the kinetics of ternary nucleation is developed based on the nucleation flux theory derived by Langer, 1969, Annals of Physics 54, 258–275. The method for obtaining the ternary nucleation flux is based on the solution of a Fokker–Planck equation for the concentration of clusters where both number and cluster energy fluctuations are included. The theory is applied to a nonideal solution of water–sulphuric acid that is nonideally mixed with ammonia. The nucleation rates predicted for this ternary system studied show a considerable increase on the nucleation rate compared to the binary water–sulphuric acid system for gaseous concentrations of ammonia which are likely to occur in the atmosphere. The results of the present study are in qualitative agreement with current laboratory and theoretical studies where a considerable enhancement in the nucleation rate is observed with the addition of tens of parts per trillion by volume of NH3 in the binary H2SO4–H2O system.  相似文献   

3.
The present work compares the efficiency of homogenous Fenton and photo-Fenton processes in the presence of Fe(III)–EDDS complex under different experimental conditions. 4-tert-Butylphenol (4-t-BP), which is one of the endocrine disrupting chemicals, was used as a model pollutant to investigate the Fenton and photo-Fenton application. The efficiency of homogenous photo-Fenton process was significantly much higher than homogenous Fenton process, which is due to the rapid formation of Fe2+ under UV irradiation of the iron complex and the photochemical formation of HO? from the photolysis of the complex Fe(III)–EDDS. Through the degradation of 4-t-BP, the effect of Fe(III)–EDDS concentration, H2O2 concentration, pH, and oxygen was investigated in both processes. Such trend was also correlated with pH calculating the polychromatic Fe2+ quantum yield formation at pH 4.0, 6.0, and 8.6. The results showed that at high Fe(III)–EDDS and H2O2 concentrations, a negative effect was found. By the way, the Fenton process was found to be enhanced at basic pH. These results can be very useful for the use and optimization of such iron complex in water treatment process as function of different physico-chemical conditions.  相似文献   

4.
In this paper the results are reported of a study on the concentration of macroelements (N, P, K, Ca, Mg, S and Fe) and heavy metals (Ni, Cr, Co, V, Zn, Mn, Pb, Cd, Cu, Hg, Ba and Sr) in soil and in three species of the evergreen plants Ilex aquifolium, Mahonia aquifolium and Rhododendron catawbiense. These plants are collected in the Botanical Garden of the Polish town Wrocław (which is exposed to atmospheric exhausts of heavy traffic, chemical factories, metal smelters and a heat and power plant partly alimented with lignite and coals) and in two presumed unpolluted reference (background) sites, one in Poland (the Dendrological Garden in Wojslawice near Niemcza, south from Wrocław) and the other in The Netherlands (the Botanical Garden of the University of Nijmegen).Analyses of both soil and plant samples point to the pollution of the Wrocław Botanical Garden by Ni, Cr, Co, Cd via the atmosphere and pollution by Zn, Pb and Hg probably via atmosphere and soil. Especially pollution with Hg via soil is supported by a significant positive correlation between Hg content in soil and in all the examined species of which Ilex aquifolium seemed to be the best monitor of soil pollution with this element.  相似文献   

5.
Environmental Science and Pollution Research - The use of renewable energy is critical to the long-term development of global energy. Geothermal power plants (GPPs) differ in the technology they...  相似文献   

6.
A three-dimensional numerical model is described which considers the effects of advection, diffusion, coagulation, gravitational settling, gas-to-particle (g-to-p) conversion and interactions with the ambient air on the evolution with time of particle size distributions in power plant plumes. From inputs of an atmospheric temperature, humidity and wind sounding, and the concentrations of particles and trace gases emitted from a power plant and in the ambient air, the model provides predictions of the particle size distributions, total particle concentrations, concentrations of trace gases, g-to-p conversion rates and the light-scattering coefficient of the particles at points in the plume downwind of the stack.Comparisons of the model predictions with airborne measurements obtained in the plumes from two coal-fired power plants show that the model is capable of predicting many of the principal features of the evolution of the particle size distributions and related parameters for transit distances up to at least 30 km. The model predicts maximum g-to-p conversion rates at the edges of the plumes where the predicted g-to-p conversion rates are comparable to values derived from field measurements. Elsewhere in the plumes the predicted g-to-p conversion rates are about an order of magnitude lower than the average values deduced from field measurements.  相似文献   

7.
A mathematical model is presented for the dispersion and chemical reactions of pollutants in chimney plumes. It assumes that atmospheric dispersion is such that an inert constituent would be distributed in a Gaussian fashion downwind of the chimney, uses a discreet approximation approach to obtain concentrations of reactive pollutants, and can account for reactive species entrained into the plume from the ambient air. The model is used to interpret some data on NO2 formation in the plume of a power plant chimney.  相似文献   

8.
Some results concerning characteristics of airflow within and above a forest are presented: horizontal mean windspeed profiles, turbulence intensities, turbulent transfer coefficients, autocorrelation curves, energy spectra, turbulence scales, microscales.To understand the mechanisms of SO2 diffusion within and above a forest, we have to calculate SO2 fluxes at the top of the canopy and two methods are used for this: the first one uses speed fluctuations and the second one mean speed values.The aim of that work is to determine the behaviour of the forest towards SO2 and to develop a diffusion model of SO2 with associated absorption by the roughness.  相似文献   

9.
Environmental Science and Pollution Research - The study used scattered literature to summarize the effects of excess Cd, As, and Pb from contaminated soils on plant secondary metabolites/bioactive...  相似文献   

10.
Trichloroacetic acid (TCA; CCl3COOH) is a phytotoxic chemical. Although TCA salts and derivatives were once deployed as herbicides against perennial grasses and weeds, their use has since been banned because of their indiscriminate herbicidal effects on woody plant species. However, TCA can also be formed in the atmosphere. For instance, high-volatile C2-chlorohydrocarbons tetrachloroethene (TECE, C2Cl4) and 1,1,1-trichloroethane (TCE, CCl3CH3) can react to TCA and other substances under oxidative conditions here. Owing to further industrialisation of Southeast Asia, South Africa and South America, a rise can be expected in the use of TECE as solvents in the metal and textile industries of these regions in the southern hemisphere (SH). The increasing emissions of this substance—together with the rise in the atmospheric oxidation potential caused by urban activities, slash and burn agriculture and forest fires in the SH—will result in the increased input/formation of TCA in the vegetation located on the lee side of these emission sources. By means of biomonitoring studies, inputs/formation of TCA related to the climatic conditions were detected at various locations in South America, Africa, and Europe.  相似文献   

11.
A reactive plume model that treats secondary aerosol formation is used to investigate the major physical and chemical processes that affect the rate of sulfate and nitrate aerosol formation in power plant plumes. The reactive plume model is evaluated with experimental data collected in three power plant plumes, and model performance is shown to be quite satisfactory. One of these case studies is used to perform singleparameter and multi-parameter analyses of the sensitivity of sulfate and nitrate aerosol concentrations to various meteorological, air quality and chemical kinetic parameters. The results suggest that sulfate aerosol concentrations are most sensitive to relative humidity and temperature at high relative humidity, whereas nitrate aerosol concentrations are most sensitive to temperature, particularly at low relative humidity. The importance of the NOx/reactive hydrocarbon chemistry to sulfate and nitrate aerosol formation is examined.  相似文献   

12.
The study deals with the identification and the determination of the main monoterpenes (α- and β-pinene) released by the pines in the Landes Forest in France. The measurements were taken after preconcentration using TENAX-GC and thermal desorption. The diurnal variation of atmospheric concentration of α- and β-pinene is established; it is less than 0.5 ppbV in the daytime and varies from 2 to 4 ppbV in the night-time. These variations are explained by the fact that the photochemical reactions and the turbulence phenomena to which the terpenes are exposed change quite radically from day to night. The terpene concentration, higher at 5 m than at 25 m, would seem to confirm the existence of a terpene source at ground level.  相似文献   

13.
Environmental Science and Pollution Research - Environmental pollution is one of the major problems facing human health, ecosystems, and biodiversity. This is particularly the case for water...  相似文献   

14.
The Mar Piccolo of Taranto, classified as a ‘Site of National Interest’ (SIN), is a semi-enclosed basin divided into two inlets with lagoon features and sea influences, seriously affected by anthropic activities. In the framework of the RITMARE project, a study has been carried out to evaluate the functionality of this ecosystem. As part of this work, measurements of the water abiotic parameters were performed in order to assess the physical–chemical features of this area after the activation, in the last decade, of treatment plants for various urban and industrial dumping. Seawater intrusions and continental inputs, as well as several submarine freshwater springs, clearly affect physical–chemical characteristics of the water column in the two inlets. This finding suggests that small-scale patterns in water circulation have the potential to influence the chemical properties of the seawater. The comparison with a 20-year dataset reveals a drastic decrease in nutrient concentrations after the year 2000, validating the functionality of the treatment plants. The reduction of nutrient inputs into the basin (up to ?90 % in the first inlet characterized by lower hydraulic residence time) has changed the biogeochemical characteristics of the Mar Piccolo from being relatively eutrophic to moderately oligotrophic.  相似文献   

15.
In this study, the BC aerosol measured at two very different urban sites is compared in terms of concentration, seasonal variation, and size distribution. During a 14 month study, one impactor sample was performed each month on a day with typical meteorological conditions. One (Vienna) or three (Uji) filter samples were obtained during the sampling time of the impactors. BC concentration in both the filter and impactor samples was analyzed with an optical technique (integrating sphere technique), where a calibration curve obtained from commercial carbon black is used to convert the optical signal to BC mass. Gravimetric mass concentration was measured at both sites. The gravimetric mass size distribution was measured only in Vienna. At both sites, the yearly average of the BC concentration on the sampling days was around 5 μg m−3. In Vienna, some seasonal trend with high concentrations during the cold season was observed, while in Uji, no pronounced seasonal trend was found. The BC size distribution in Uji was distinctly bimodal in the submicron size range. Log-normal distributions were fitted through the impactor data. The average BC mass median diameters (MMD) of the two submicron modes were 0.15 and 0.39 μm. Each mode contained about the same amount of BC mass. In Vienna only one submicron BC mode (average MMD 0.3 μm) was found because of the low size resolution of the impactor. An analysis of humidity effects on the MMDs of BC (both sites) and gravimetric mass (Vienna only) indicates that the Vienna aerosol is partly mixed internally with respect to BC, while the Uji aerosol seems to be externally mixed.  相似文献   

16.
Environmental Science and Pollution Research - Dissolved organic matter (DOM) and microbes are key in the planetary carbon cycle, and research on them can lead to a better understanding of the...  相似文献   

17.
Brazilian soybean cultivars (Glycine max Sambaíba and Tracajá) routinely grown in Amazonian areas were exposed to filtered air (FA) and filtered air enriched with ozone (40 and 80 ppb, 6 h/day for 5 days) to assess their level of tolerance to this pollutant by measuring changes in key biochemical, physiological, and morphological indicators of injury and in enzymatic and non-enzymatic antioxidants. Sambaíba plants were more sensitive to ozone than Tracajá plants, as revealed by comparing indicator injury responses and antioxidant stimulations. Sambaíba exhibited higher visible leaf injury, higher stomatal conductance, and a severe decrease in the carbon assimilation rate. Higher ozone level (80 ppb) caused an increase in cell death in both cultivars. Levels of malondialdehyde and hydrogen peroxide also increased in Tracajá exposed under 80 ppb. Sambaíba plants exhibited decreases in ascorbate and glutathione levels and in enzymatic activities associated with these antioxidants. The higher tolerance of the Tracajá soybean appeared to be indicated by reduced physiological injuries and lower stomatal conductance, which might decrease the influx of ozone and enhance oxidation-reduction reactions involving catalase, ascorbate peroxidase, ascorbate, and glutathione, most likely stimulated by higher hydrogen peroxide.  相似文献   

18.
Environmental Science and Pollution Research - Concentrations of 22 essential and non-essential trace elements (Be, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th, U, and...  相似文献   

19.
Gil C  Boluda R  Ramos J 《Chemosphere》2004,55(7):1027-1034
This study determines total levels of three (Cd, Pb and Ni) potentially toxic trace elements in western Almería (Spain) greenhouse surface soil horizons using microwave digestion; it establishes the geochemical baseline concentration, and it investigates possible relationships between soil properties and elemental concentrations. The results show that the soil concentration of these heavy metals is lower than mentioned in the European and Spanish normative, but they are higher than those reported by other authors working on agricultural soils. The obtained geochemical baseline concentrations (mg kg(-1)) were: Cd 0.4-0.8, Pb 2.5-89.9 and Ni 16.1-30.7. Using the upper baseline criterion, 88% of greenhouse soils have relatively higher content of heavy metals because of their Cd, Pb and Ni concentration. Moreover, soil properties are related to heavy metals contents suggesting that among Cd, Pb and Ni have a similar origin and those total metal concentrations are controlled primarily by soil compositions.  相似文献   

20.

Purpose  

The present research aims to investigate the individual and interactive effects of chlorine dose/dissolved organic carbon ratio, pH, temperature, bromide concentration, and reaction time on trihalomethanes (THMs) formation in surface water (a drinking water source) during disinfection by chlorination in a prototype laboratory-scale simulation and to develop a model for the prediction and optimization of THMs levels in chlorinated water for their effective control.  相似文献   

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