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1.
The increasing size of concentrated animal feeding operations has led to a concomitant increase in the land-application of manure, which has spawned research on the concentrations and environmental risk assessment of natural and synthetic hormones in animal manures. 17β-Trenbolone acetate (TBA) is widely used in the United States for improving daily gains in beef cattle and is often administered in combination with 17β-estradiol (17β-E2). Trenbolone (TB) and E2 isomers and their metabolites were quantified in manure collection pits and lagoon effluent from beef cattle implanted with the commercial anabolic preparation Ravoler-S (containing 140 mg 17β-trenbolone acetate and 28 mg 17β-E2). Manure pit and lagoon effluent samples were collected weekly for 9 weeks post implanting and analyzed using reverse-phase liquid chromatography tandem mass spectrometry. 17α-TB was the most abundant androgen with the highest concentration observed 2 weeks post implant. 17β-TB and trendione peaked at the end of week 2 and 4, respectively. For the estrogens, the highest concentrations for estrone (E1), estriol (E3), and 17α-E2 were observed after week 4, 6, and 8, respectively. 17β-E2 concentrations were the lowest of the estrogens and erratic over time. In lagoon water, which is used for irrigation, 17α-TB and E1 had the highest detected hormone concentrations (1.53 and 1.72 μg L−1, respectively). Assuming a 1-2 order dilution during transport to surface water, these hormone levels could lead to concentrations in receiving waters that exceed some of the lowest observable effect levels (LOELs) reported for hormones (e.g., 0.01-0.03 μg L−1).  相似文献   

2.
Although estrogens originating from dairy manure applied to agricultural soils as a fertilizer can potentially contaminate surface water and groundwater, the variables that control transport are poorly understood. Our objective was to assess the potential for off-site movement of endogenous dairy cattle estrogens when manure is applied on fields at agronomically relevant fertilization rates. Estrone (E1), 17α-estradiol (α-E2), and 17β-estradiol (β-E2) were used in laboratory sorption, desorption, and transformation incubations with both manure and an agriculturally relevant soil. Sorption on manure containing 44% organic carbon exceeded sorption on soil containing 0.8% organic carbon by 20 to 150 times, following the pattern of β-E2 > α-E2 > E1. Approximately 20% of E1 and 17% of α-E2 were desorbed from manure, whereas only about 4% of β-E2 was desorbed. Thirty to seventy percent of α-E2 and β-E2 were converted to E1 in soil and manure, making it imperative that transformation reactions be considered when predicting transport and potential biological effects in the environment. Overall results indicate that high organic carbon concentrations and relatively low amounts of desorption inhibit the potential for off-site transport of endogenous dairy manure estrogens.  相似文献   

3.
Ammonia-nitrogen flux (NH3-N=(14/17)NH3) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of flux variation was made with respect to lagoon surface water temperature (∼15 cm below the surface), lagoon water pH, total aqueous phase NHx(=NH3+NH4+) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3°C. The pH ranged in value from 6.8 to 8.1. Aqueous NHx concentration ranged from 37 to 909 mg N l−1, and TKN varied from 87 to 950 mg N l−1. Fluxes were the largest at the primary lagoon in Kenansville, NC (March 1999) with an average value of 120.3 μg N m−2 min−1, and smallest at the tertiary lagoon in Rocky Mount, NC (November 1998) at 40.7 μg N m−2 min−1. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NHx concentration. The NH3-N flux may be modeled as ln(NH3-N flux)=1.0788+0.0406TL+0.0015([NHx]) (R2=0.74), where NH3-N flux is the ammonia flux from the lagoon surface in μg N m−2 min−1, TL is the lagoon surface water temperature in °C, and [NHx] is the total ammonia-nitrogen concentration in mg N l−1.  相似文献   

4.
The estrogenic activities of source water from Yangtze River, Huaihe River, Taihu Lake and groundwater in Yangtze River Delta in the dry and wet season were determined by use of reporter gene assays based on African green monkey kidney (CV-1) cell lines. Higher estrogenic activities were observed in the dry season, and the estrogenic potentials in water samples from Taihu Lake were greater than other river basins. None of the samples from groundwater showed estrogen receptor (ER) agonist activity. The 17β-Estradiol (E2) equivalents (EEQs) of water samples in the dry season ranged from 9.41 × 10?1 to 1.20 × 101 ng E2 L?1. In the wet season, EEQs of all the water samples were below the detection limit as 9.00 × 10?1 ng E2 L?1 except for one sample from Huaihe River. The highest contribution of E2 was detected in Yangtze River as 99% of estrogenic activity. Nonylphenol (NP, 100% detection rate) and octylphenol (OP, 100% detection rate) might also be responsible for the estrogenic activities in water sources. Potential health risk induced by the estrogenic chemicals in source water may be posed to the residents through water drinking.  相似文献   

5.
Canopy scale emissions of isoprene and monoterpenes from Amazonian rainforest were measured by eddy covariance and eddy accumulation techniques. The peak mixing ratios at about 10 m above the canopy occurred in the afternoon and were typically about 90 pptv of α-pinene and 4–5 ppbv of isoprene. α-pinene was the most abundant monoterpene in the air above the canopy comprising ≈50% of the total monoterpene mixing ratio. Measured isoprene fluxes were almost 10 times higher than α-pinene fluxes. Normalized conditions of 30°C and 1000 μmol m−2 s−1 were associated with an isoprene flux of 2.4 mg m−2 h−1 and a β-pinene flux of 0.26 mg m−2 h−1. Both fluxes were lower than values that have been specified for Amazon rainforests in global emission models. Isoprene flux correlated with a light- and temperature-dependent emission activity factor, and even better with measured sensible heat flux. The variation in the measured α-pinene fluxes, as well as the diurnal cycle of mixing ratio, suggest emissions that are dependent on both light and temperature. The light and temperature dependence can have a significant effect on the modeled diurnal cycle of monoterpene emission as well as on the total monoterpene emission.  相似文献   

6.
This paper reports on a field study that was part of a large-scale, multi-seasonal research study with the North Carolina Department of Environment, Health, and Natural Resources, to measure nitrogen emissions from an intensive swine confinement facility. The study measured emission rates using tracer gases and a horizontal network of open-path Fourier transform infrared (FTIR) optical rays placed less than a meter above the surface of an approximately 6 acre intensive swine waste lagoon in Eastern North Carolina. This network of rays simultaneously monitored the ammonia and the tracer gases every 2 min. The open-path measurements were combined with the mathematical mapping techniques of computer-assisted tomography (CAT) to create two-dimensional concentration maps of the gases for the entire lagoon surface. For this study, a ratioing technique was applied to the tomographic concentration maps to estimate the nitrogen emission rates (from ammonia) using known tracer emission rates. The average concentrations of ammonia measured in August, November, and May were 0.81, 0.25, and 0.74 ppm, respectively. In general, ammonia concentrations were lowest at the center of the lagoon and could vary across a lagoon from 2 to 4 times depending upon the time of the day and the meteorological conditions. Emission rates were only calculated for November and May, up until midnight. In November 1997, the average flux was 1910 μg N m−2-min−1 (range 542–4695 μg N m−2-min−1) and in May the average flux was 4775 μg N m−2-min−1 (range 2572–8499 μg N m−2-min−1). This study was important because it not only provided nitrogen emission rate measurements using a new technology which can measure concentrations over large areas in real time, it was the first large-scale outdoor field study using this application.  相似文献   

7.
We determined hourly emissions of isoprene, monoterpenes and sesquiterpenes from Siberian larch, one of the major tree species in Siberian forests. Summer volatile organic compounds (VOCs) emission from Siberian larch consisted mainly of monoterpenes (about 90%). The monoterpene emission spectrum remained constant during the measurement period, almost half was sabinene and other major monoterpenes were Δ3-carene, β- and α-pinene. During spring and summer, about 10% of the VOCs were sesquiterpenes, mainly α-farnesene. The sesquiterpene emissions declined to 3% in the fall. Isoprene, 2-methyl-3-buten-2-ol (MBO) and 1,8-cineole contributed to less than 3% of the VOC emission during the whole period. The diurnal variation of the emissions could be explained using a temperature-dependent parameterization. Emission potentials normalized to 30 °C were 5.2–21 μg gdw−1 h−1 (using β-value of 0.09 °C−1) for monoterpenes and 0.4–1.8 μg gdw−1 h−1 (using β-value of 0.143 °C−1, mean of determined values) for sesquiterpenes. Normalized monoterpene emission potentials were highest in late summer and elevated again in late fall. Sesquiterpene emission potentials were also highest in late summer, but decreased towards fall.  相似文献   

8.
A dynamic soil enclosure was used to characterise monoterpene emissions from 3 soil depths within a Picea sitchensis (Sitka spruce) forest. In addition, a dynamic branch enclosure was used to provide comparative emissions data from foliage. In all cases, limonene and α-pinene dominated monoterpene soil emissions, whilst camphene, β-pinene and myrcene were also present in significant quantities. α-Phellandrene, 3-carene and α-terpinene were occasionally emitted in quantifiable amounts whilst cymene and cineole, although tentatively identified, were always non-quantifiable. Total daily mean monoterpene emission rates, normalised to 30°C, varied considerably between soil depths from 33.6 μg m−2 h−1 (range 28.3–38.4) for undisturbed soil, to 13.0 μg m−2 h−1 (8.97–16.4) with uppermost layer removed, to 199 μg m−2 h−1 (157–216) with partially decayed layer removed, suggesting that the surface needle litter was the most likely source of soil emissions to the atmosphere. Relative monoterpene ratios did not vary significantly between layers. Foliar monoterpenes exhibited a similar emission profile to soils with the exceptions of camphene and 3-carene whose contributions decreased and increased, respectively. Emission rates from foliage, normalised to 30°C were found to have a daily mean of 625 ng g−1 dw h−1 (299–1360). On a land area basis however, total soil emissions were demonstrated to be relatively insignificant to total emissions from the forest ecosystem.  相似文献   

9.
Carbon dioxide (CO2) release from manure was investigated under field conditions in one of the compartments in a mechanically ventilated fattening pig house. The potential of CO2 release was tested in the emptied compartment by imposing high ventilation rate and measuring CO2 concentrations in the incoming and exhaust air. When the compartment was filled with pigs, a model of tranquil CO2 exhalation rate (TCER) was used to estimate the part of CO2 produced by animals, in addition to the measurement of CO2 concentrations and ventilation rate. Useful data were extracted from 135 days of continuously measured field data obtained when the housing system was in steady-state. The CO2 release per m2 of pit surface was 18.4 and 25.8 g h−1 m−2 in the emptied pig compartment during the impulse and pulse ventilation rate tests, respectively. It ranged from 1.1 and 116.7 g h−1 m−2 and averaged 42.1 g h−1 m−2 during the 135-day continuous field measurement. In 128 of the 135 days when the compartment was filled with pigs, the mean CO2 release from the manure reached an average of 37.5% of the TCER by pigs, instead of less than 5% believed by many researchers. The maximum CO2 release rate in 2-h steady-state measurements was 94% of the TCER by pigs. This research demonstrated that, in the previous knowledge, there might be a serious underestimation of the CO2 release from the manure in pig houses. The total pig weight, manure temperature and ventilation rate were found the most important variables related to the CO2 release. A mathematical model was developed to estimate the CO2 release as a function of these three variables with R2=0.525.  相似文献   

10.
The occurrence of persistent toxic substances (PTS) in China and possibly their regional transport in the Yellow and East China Seas region was studied. Organochlorines in atmospheric gas-phase and particulate matter were collected by high-volume sampling (filters and polyurethane foams) during 2 weeks in June 2003 (dry season) simultaneously at a Yellow Sea coastal site in an urban area, Qingdao, China, and a rural island site, Gosan, Jeju Island, Korea. Using GC methods, the samples were analysed for 9 persistent organic pollutants (POPs) regulated under the global POP convention, namely aldrin, chlordane (cis- and trans-isomers CC and TC), DDT and metabolites (o,p′-DDT, p,p′-DDD, and p,p′-DDE), dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex and PCB (congeners number 28, 52, 101, 153 and 180), and for hexachlorocyclohexane (α-, β- and γ-isomers), a PTS and now considered for regulation under the convention, too. At the coastal site additionally o,p′-DDE and -DDD, β-endosulfan, isodrin, heptachlorepoxide and δ-HCH, and at the island site additionally p,p′-DDT and 12 additional PCB congeners were analysed. 9 samples were collected at the coastal and 15 (for PCBs 5) at the island site. Long-range advection pathways were determined based on analysed back-trajectory calculations.The mean concentrations of DDT and its metabolites, HCB, HCH, and PCB at the coast were in the 100–1000 pg m−3 range. Higher concentrations prevailed during nighttime. The levels were in general lower at the island site, but not for DDT. Local sources are likely. PCBs were even 2 orders of magnitude lower, suggesting that PCBs are not subject to regional transport but elevated concentrations in air are limited to the source areas. Organochlorine pesticide levels on the other hand were seemingly determined by regional transport over Mainland China rather than by emissions in the coastal area. The currently used pesticides mirex and chlordane were found at elevated levels, i.e. 79 (6.6–255) and 36 (<6–71) pg m−3, respectively, at the coast but not over the island. The POPs pesticides aldrin, dieldrin and endrin, never registered in China, were mostly found at <10 pg m−3 except for endrin at the coastal site (up to 400 pg m−3) and aldrin at the island site (up to 50 pg m−3).  相似文献   

11.
Atmospheric monitoring of PCBs and chlorinated pesticides (e.g., HCHs, chlordanes, and DDTs) in Galveston Bay was conducted at Seabrook, Texas. Air and wet deposition samples were collected from 2 February 1995 and continued through 6 August 1996. Vapor total PCB (tPCB) concentrations in air ranged from 0.21 to 4.78 ng m−3 with a dominance of tri-chlorinated PCBs. Dissolved tPCBs in rain ranged from 0.08 to 3.34 ng l−1, with tetra-chlorinated PCBs predominating. The predominant isomers found in air and rain were α- and γ-HCH, α- and γ-chlordanes, 4,4′-DDT, and dieldrin. The concentrations of PCBs and pesticides in the air and rain revealed no clear seasonal trend. Elevated levels of PCBs in the air occurred when temperatures were high and wind came from urban and industrialized areas (S, SW, NW, and W of the site). Concentrations of HCHs were elevated in April, May, and October, perhaps due to local and/or regional applications of γ-HCH (lindane). Other pesticides showed no notable temporal variation. When winds originated from the Gulf of Mexico (southeasterly), lower concentrations of organochlorines were detected in the air. The direct deposition rate (wet+dry) of PCBs to Galveston Bay (6.40 μg m−2 yr−1) was significantly higher than that of pesticides by a factor of 5–10. The net flux from gas exchange estimated for PCBs was from Galveston Bay water to the atmosphere (78 μg m−2 yr−1). Gas exchange of PCBs from bay water to the atmosphere was the dominant flux.  相似文献   

12.
The gas-phase ozonolysis of (E)-β-farnesene was investigated in a 3.91 m3 atmospheric simulation chamber at 296 ± 2 K and relative humidity of around 0.1%. The relative rate method was used to determine the reaction rate coefficient of (4.01 ± 0.17) × 10?16 cm3 molecule?1 s?1, where the indicated errors are two least-squares standard deviations and do not include uncertainties in the rate coefficients for the reference compounds (γ-terpinene, cis-cyclooctene and 1,5-cyclooctadiene). Gas phase carbonyl products were collected using a denuder sampling technique and analyzed with GC/MS following derivatization with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA). The reaction products detected were acetone, 4-oxopentanal, methylglyoxal, 4-methylenehex-5-enal, 6-methylhept-5-en-2-one, and (E)-4-methyl-8-methylenedeca-4,9-dienal. A detailed mechanism for the gas-phase ozonolysis of (E)-β-farnesene is proposed, which accounts for all of the products observed in this study. The results of this work indicate that the atmospheric reaction of (E)-β-farnesene with ozone has a lifetime of around 1 h and is another possible source of the ubiquitous carbonyls, acetone, 4-oxopentanal and 6-methylhept-5-en-2-one in the atmosphere.  相似文献   

13.
Gaseous methane (CH4) emissions from a swine waste holding lagoon were determined periodically during the year. Micrometeorological techniques were used in order that emission rates from the lagoon were measured under ambient conditions with little disturbance to the natural environment. During the cold winter measurement period, CH4 fluxes were linearly related to lagoon water temperature below 22°C (r=0.87). During warmer measurement periods, both water and air temperatures and windspeed affected emissions rates. In general, flux rates followed a diurnal pattern with greater fluxes during the day when both temperature and windspeed were greatest. Mathematical models using air and water temperature and windspeed factors could explain 47 to 75% of the variation in fluxes. Daily emission rates ranged from 1 to 500 kg CH4 ha−1 d−1. The average flux for the year was 52.3 kg CH4 ha−1 d−1 which corresponded to about 5.6 kg CH4 animal−1 yr−1 from the primary lagoon.  相似文献   

14.
The aerosol scattering properties were investigated at two continental sites in northern China in 2004. Aerosol light scattering coefficient (σsp) at 525 nm, PM10, and aerosol mass scattering efficiencies (α) at Dunhuang had a mean value of 165.1±148.8 M m−1, 157.6±270.0 μg m−3, and 2.30±3.41 m2 g−1, respectively, while these values at Dongsheng were, respectively, 180.2±151.9 M m−1, 119.0±112.9 μg m−3, and 1.87±1.41 m2 g−1. There existed a seasonal variability of aerosol scattering properties. In spring, at Dunhuang PM10, σsp, and α were 184.1±211.548 μg m−3, 126.3±89.6 M m−1, and 1.05±0.97 m2 g−1, respectively, and these values at Dongsheng were 146.4±142.1 μg m−3, 183.4±81.7 M m−1, and 1.98±1.52 m2 g−1, respectively. However, in winter at Dunhuang PM10, σsp, and α were 158.1±261.4 μg m−3, 303.3±165.2 M m−1, and 3.17±1.93 m2 g−1, respectively, and these values at Dongsheng were 155.7±170.1 μg m−3, 304.4±158.1 M m−1, and 2.90±1.72 m2 g−1, respectively. σsp and α in winter were higher than that in spring at both the sites, which coincides with the characteristics of dust aerosol and pollution aerosol. Overall, the dominant aerosol types in spring and winter at both sites in northern China are dust aerosol and pollution aerosol, respectively.  相似文献   

15.
Measurements in the exhaust plume of a petrol-driven motor car showed that molecular cluster ions of both signs were present in approximately equal amounts. The emission rate increased sharply with engine speed while the charge symmetry remained unchanged. Measurements at the kerbside of nine motorways and five city roads showed that the mean total cluster ion concentration near city roads (603 cm?3) was about one-half of that near motorways (1211 cm?3) and about twice as high as that in the urban background (269 cm?3). Both positive and negative ion concentrations near a motorway showed a significant linear increase with traffic density (R2 = 0.3 at p < 0.05) and correlated well with each other in real time (R2 = 0.87 at p < 0.01). Heavy duty diesel vehicles comprised the main source of ions near busy roads. Measurements were conducted as a function of downwind distance from two motorways carrying around 120–150 vehicles per minute. Total traffic-related cluster ion concentrations decreased rapidly with distance, falling by one-half from the closest approach of 2 m to 5 m of the kerb. Measured concentrations decreased to background at about 15 m from the kerb when the wind speed was 1.3 m s?1, this distance being greater at higher wind speed. The number and net charge concentrations of aerosol particles were also measured. Unlike particles that were carried downwind to distances of a few hundred metres, cluster ions emitted by motor vehicles were not present at more than a few tens of metres from the road.  相似文献   

16.
The fungi and bacterial levels of the indoor air environments of 77 office buildings were measured in winter and a comparison was made between the buildings with microbe sources in their structures and those without such sources. Penicillium, yeasts, Cladosporium and non-sporing isolates were the commonest fungi detected in the indoor air and in settled dust, in both the mould-damaged and control buildings. Aspergillus ochraceus, Aspergillus glaucus and Stachybotrys chartarium were found only in environmental samples from the mould-damaged buildings. Some other fungi, with growth requiring of water activity, aw, above 0.85, occurred in both the reference and mould-damaged buildings, but such fungi were commoner in the latter type of buildings. The airborne concentrations of Penicillium, Aspergillus versicolor and yeasts were the best indicators of mould damage in the buildings studied. Penicillium species and A. versicolor were also the most abundant fungi in the material samples. This study showed that the fungi concentrations were very low (2–45 cfu m−3 90% of the concentrations being <15 cfu m−3) in the indoor air of the normal office buildings. Although the concentration range of airborne fungi was wider for the mould-damaged buildings (2–2470 cfu m−3), only about 20% of the samples exceeded 100 cfu m−3. The concentrations of airborne bacteria ranged from 12 to 540 cfu m−3 in the control buildings and from 14 to 1550 cfu m−3 in the mould-damaged buildings. A statistical analysis of the results indicated that bacteria levels are generally <600 cfu m−3 in office buildings in winter and fungi levels are <50 cfu m−3. These normal levels are applicable to subarctic climates for urban, modern office buildings when measurements are made using a six-stage impactor. These levels should not be used in evaluations of health risks, but elevated levels may indicate the presence of abnormal microbe sources in indoor air and a need for additional environmental investigations.  相似文献   

17.
Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10–1300 μmol m−2 s−1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7% of the total VOC (winter) to 97% (late summer). The monoterpenes α-pinene, camphene, sabinene, β-pinene, myrcene, limonene, trans-ocimene and γ-terpinene were also emitted, with α-pinene being the dominant monoterpene during most the year. Trans-ocimene represented 33–66% of the total monoterpene during the hottest months from June to September. VOC emissions were found to be accurately predicted using existing algorithms. Standard (normalised) emission factors of VOCs from gorse were calculated using experimental parameters measured during the experiment and found to fluctuate with season, from 13.3±2.1 to 0.1±0.1 μg C (g dwt)−1 h−1 in August 1995 and January 1995, respectively, for isoprene, and from 2.5±0.2 to 0.4±0.2 μg C (g dwt)−1 h−1 in July and November 1995, respectively, for total monoterpenes. No simple clear relation was found to allow prediction of these seasonal variations with respect to temperature and light intensity. The effects of using inappropriate algorithms to derive VOC fluxes from gorse were assessed for isoprene and monoterpenes. Although on an annual basis the discrepancies are not significant, monthly estimation of isoprene were found to be overestimated by more than a factor of 50 during wintertime when the seasonality of emission factors is not considered.  相似文献   

18.
Agricultural wastes are a source of steroid estrogens and, if present, conjugated estrogens may add to the estrogen load released to soil and aquatic environments. Dairy shed effluent samples were collected from 18 farms for analysis of steroid estrogens by GC-MS, conjugated estrogens by LC-MS-MS, and estrogenic activity by E-screen in vitro bioassay. 17α-estradiol was found at highest concentrations (median 730 ng l−1), followed by estrone (100 ng l−1) and 17β-estradiol (24 ng l−1). Conjugated estrogens (estrone-3-sulfate, 17α-estradiol-3-sulfate and 17β-estradiol-3,17-disulfate) were measured in most samples (12-320 ng l−1). Median estrogenic activity was 46 ng l−1 17β-estradiol equivalents. Conjugated estrogens contributed up to 22% of the total estrogen load from dairy farming, demonstrating their significance. Steroid estrogens dominated overall estrogenic activity measured in the samples. Significantly, 17α-estradiol contributed 25% of overall activity, despite potency 2% that of 17β-estradiol, highlighting the importance in environmental risk assessments of this previously neglected compound.  相似文献   

19.
The influence of 222Rn exhalation from walls and air exchange (low ventilation rates ν<0.3 h-1) upon its concentration in room air has been considered. It was found that the radon concentration reachs 84 Bq m-3 at exhalation and ventilation rates of 66 Bq hm-2 and 0.28 h-1, respectively. The radon concentration and the ultrafine fraction fp of potential α energy concentration as well as the equilibrium factor F of the short-lived radon progeny were also determined in three different completely closed rooms. An electroprecipitation method was applied for determining the 222Rn concentration while a single wire-screen technique was used for the determination of ultrafine radon progeny. During the measurements, the radon concentrations were varied between 33 and 134 with a mean value 89 Bq m-3. A mean ultrafine fraction (fp) of 0.16 was obtained at a mean aerosol particle concentration (Z) of 1700 cm-3 and a mean equilibrium factor (F) of 0.33. The obtained mean value of fp was found to be about five times higher than the value reported in the ICRP publication (fp=0.03). The attachment rate (X), the deposition rate (qf) and the deposition velocity (vfd) of the ultrafine radionuclide 218Po were calculated. A mean value of X was found to be 49 h-1 at a mean qf of 46 h-1 and a mean vfd of 4.6 m h-1. The attachment coefficient β of 218Po was found to vary between 0.016 and 0.047 with a mean value 0.028 cm3 h-1.  相似文献   

20.
Current-used pesticides commonly applied in Alsace region (Eastern France) on diverse crops (maize, vineyard, vegetables, etc.) were analysed, together with Lindane, in rainwater between January 2002 and June 2003 simultaneously on two sites situated in a typical rural (Erstein, France) and urban area (Strasbourg, France).Rainwater samples were collected on a weekly basis by using two automatic wet only collectors associated with an open collector for the measurement of rainwater height.Pesticides were analysed by GC-MSMS and extracted from rainwater by SPME. Two runs were performed. The first one was performed by using a PDMS (100 μm) fibre for pesticides where direct injection into GC is possible (alachlor, atrazine, azinphos-ethyl, azinphos-methyl, captan, chlorfenvinphos, dichlorvos, diflufenican, α- and β-endosulfan, iprodione, lindane, metolachlor, mevinphos, parathion-methyl, phosalone, phosmet, tebuconazole, triadimefon and trifluralin). The second run was performed by using PDMS/DVB fibre and this run concerns pesticides where a preliminary derivatisation step with pentafluorobenzylbromide (PFBBr) is required for very low volatiles (bromoxynil,2,4-MCPA, MCPP and 2,4-D) or thermo labiles (chlorotoluron, diuron and isoproturon) pesticides.Results showed that the more concentrated pesticides detected were those used as herbicides in large quantities in Alsace region for maize crops (alachlor, metolachlor and atrazine). Maximum concentrations for these herbicides have been measured during intensive applications periods on maize crops following by rapid decrease immediately after use.For Alachlor, most important peaks have been observed between 21 and 28 April 2003 (3327 ng L−1 at Erstein and 5590 ng L−1 at Strasbourg). This is also the case for Metolachlor where most important peak was observed during the same week.Concentrations of pesticides measured out of application periods were very low for many pesticides and some others where never detected during this period. This is the case for diflufenican which was detected only during application. Two important peaks of concentrations were observed; a first one (101 ng L−1) in Erstein in November 2002 (4–11 November) and a second one (762 ng L−1) also in Erstein (28 April–15 May).The same behaviour can be seen for chlorfenvinphos and phosalone which have been detected, respectively, 2 and 4 times in Erstein and Strasbourg at high concentrations (28 April 2003–15 May 2003, 187 ng L−1 of phosalone and 157 ng L−1 of chlorfenvinphos in Erstein).MCPP, 2,4 MCPA and 2,4-D have been detected at high concentrations in rainwater but for the other pesticides very episodically and mainly during their use in agriculture. Maximal concentrations of MCPP and 2,4 MCPA have been measured in Erstein between 28 April and 15 May (904 and 746 ng L−1, respectively).Comparison between rural and urban sites showed that concentrations in rural areas are generally higher except for pesticides commonly applied in urban areas like Diuron.No seasonal phenomenon was observed for Diuron. This herbicide has been detected in practically all of the rainwater samples in Strasbourg (40/41) with a maximum of 1025 ng L−1 (16–23 September 2002) in 38 samples on 41 in Erstein with a maximum of 317 ng L−1 (15–23 October 2002). The total concentration of Diuron measured between 4 March 2002 and 20 July 2003 is of 4721 ng L−1 in Strasbourg and 5025 ng L−1 in Erstein. This result shows that wet deposition of Diuron in urban and rural sites was equivalent and can be explained by the “urban use” of this molecule together with its potential persistence.  相似文献   

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