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1.
Carbon dioxide exchange was studied in the photosynthetic apparatus of Siberian spruce (Picea obovata Ledeb.), Siberian larch (Larix sibirica Ledeb.), and weeping birch (Betula pendula Roth.) in a mature spruce forest. Parameters of CO2 balance in different weather were characterized quantitatively on the basis of daily measurements of CO2 exchange in needles and leaves of woody plants. The percent ratios of the components of carbon balance in needles and leaves of woody plants depending on daily photosynthetic fixation of carbon were determined. In summer, trees consumed 210 kg CO2/ha (57 kg C/ha) in variable weather and 117 kg CO2/ha (32 kg C/ha) in cloudy weather. Species specificity of CO2 consumption was revealed, and the effects of environmental factors on the assimilatory activity of trees were determined.  相似文献   

2.
This study investigates the contribution of radon (222Rn)-bearing water to indoor 222Rn in thermal baths. The 222Rn concentrations in air were monitored in the bathroom and the bedroom. Particulate matter (PM, both PM10 and PM2.5) and carbon dioxide (CO2) were also monitored with portable analyzers. The bathrooms were supplied with hot spring water containing 66-260 kBq m−3 of 222Rn. The results show that the spray of hot spring water from the bath spouts is the dominant mechanism by which 222Rn is released into the air of the bathroom, and then it diffuses into the bedroom. Average 222Rn level was 110-410% higher in the bedrooms and 510-1200% higher in the bathrooms compared to the corresponding average levels when there was no use of hot spring water. The indoor 222Rn levels were influenced by the 222Rn concentrations in the hot spring water and the bathing times. The average 222Rn transfer coefficients from water to air were 6.2 × 10−4-4.1 × 10−3. The 24-h average levels of CO2 and PM10 in the hotel rooms were 89% and 22% higher than the present Indoor Air Quality (IAQ) standard of China. The main particle pollutant in the hotel rooms was PM2.5. Radon and PM10 levels in some hotel rooms were at much higher concentrations than guideline levels, and thus the potential health risks to tourists and especially to the hotel workers should be of great concern, and measures should be taken to lower inhalation exposure to these air pollutants.  相似文献   

3.
Two kerosene-fired space heaters, one white-flame convective and one blue-flame radiant, were operated in the master bedroom and living room of an unoccupied house (elevation: 1800 m) under several simulated use conditions. Tests were conducted in the master bedroom with the bedroom door and bedroom window open and closed. The heaters were operated until an 8 °C temperature rise was achieved in the room. Increases in bedroom concentrations of CO, CO2, NO, NO2, and O2 are reported. The increases in CO2 levels ranged from 2440 to 5440 mL/m3 (ppm) while the increases in NO2 levels ranged from 0.12 to 0.60 mL/m3 (ppm). The NO2 emission rate from the convective heater was reduced at the high altitude location as compared with previous emission rate measurements conducted near sea level with the same heater. In addition, inter-room pollutant transport rates are reported for bedroom tests conducted with the window closed. While inter-room pollutant transport rates were less than 10 m3 with the bedroom door closed (opening area less than 100 cm2), they ranged from 16 m3/h to 53 m3/h with the bedroom door open 2.5 cm (opening = 520 cm2), and ranged from 190 to 3400 m3/h with the door fully open (opening area = 15,000 cm2). Continuous emission rate data are reported for tests conducted with the heater in the living room.  相似文献   

4.
The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (CDGT) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO22+, uranyl carbonate complexes and UO2PO4. The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants.  相似文献   

5.
Closed landfills need after-closure rehabilitation. The chosen option should ensure greenhouse gases release, from the landfill, is not promoted once settled. The objective of this study was to estimate and confront, during different seasons, CH4, CO2 and N2O emissions under three vegetation covers in a closed landfill in Buenos Aires, Argentina. CH4 (methane), CO2 (carbon dioxide) and N2O (nitrous oxide) emissions from landfill’s technosol under spontaneous vegetation (control), Pennisetum purpureum and Miscanthus giganteus (biomass crops), were quantified with non-steady-state non-flow-through chambers, in July 2014 and from February to July 2015. A linear regression analysis was performed to relate the variables “flux of a gas” and “concentration of that gas” from the 3 treatments and 6 dates, separating the 5 sampling times. A high correlation between concentrations and fluxes of CO2 and N2O was found, but no correlation was established for CH4. Mean emissions (2014–2015) varied from: ?2.3 to 639.41 mgCH4 m?2 day?1, 3884 to 46,365 mgCO2 m?2 day?1 and 0.40 to 14.59 mgN2O m?2 day?1. Vegetation covers had no significant effect on CH4 and N2O concentration in time, but they had on CO2 concentration. Season of the year had a significant effect on concentration of the three gases. This is the first study on CH4, CO2 and N2O emissions from a landfill closed 27 years ago covered with biomass crops.  相似文献   

6.
Exposure to air pollution has been related with the most varied adverse health outcomes. This study aims to assess the impact of air pollution on the emergency hospitalization for respiratory disease in Rio de Janeiro, Brazil. The study was divided in two parts: Part I specifically addressing the air pollution assessment and Part II addressing the health assessment. Accordingly, this Part I aims to: i) evaluate the concentrations of PM10, SO2 and CO at two sites in Rio de Janeiro and compare them; ii) analyse the concentrations observed according to the national and international standards; and iii) analyse the air pollutants behaviour, namely, annually, seasonally, daily and considering weekdays/weekends variations. The pollutant concentrations were measured at two different sites in Rio de Janeiro and the analysis was performed for the period between September 2000 and December 2005. Results showed that PM10 concentrations in Rio de Janeiro exceeded the daily and annual standards imposed by the European Union, the Brazilian legislation and WHO guidelines. Regarding SO2 and CO, concentrations were, generally, below both European and Brazilian standards. Nevertheless, considering WHO guidelines, SO2 threshold for daily concentrations (20 μg m 3) was exceeded around 150 times. Behaviour assessment showed that the influence of traffic is a major factor affecting the air pollution in Rio de Janeiro.Considering the results achieved and the proven health effects of air pollution, strategies should be defined for its reduction, particularly concerning particulate matter, and consequently contribute to the protection of public health.  相似文献   

7.
Hematite, a type of inorganic-sorptive medium, was used for the removal of U (VI) from aqueous solutions. Variables of the batch experiments including solution pH, contact time, initial concentration, temperature, calcium and magnesium ions were studied. The results indicated that the adsorption capacities are strongly affected by the solution pH, contact time and initial concentration. A higher pH favors higher U (VI) removal. The adsorption was also affected by temperature and calcium and magnesium ions, but the effect is very weak. The maximum adsorption capacity (qm) only increased from 3.36 mg g−1 to 3.54 mg g−1 when the temperature was increased from 293 K to 318 K. A two-stage kinetic behavior was observed in the adsorption of uranium (VI): very rapid initial adsorption in a few minutes, followed by a long period of slower uptake. It was found that an increase in temperature resulted in a higher uranium (VI) loading per unit weight of the sorbent. The adsorption of uranium by hematite had good efficiency, and the equilibrium time of adsorbing uranium (VI) was about 6 h. The isothermal data were fitted with both Langmuir and Freundlich equations, but the data fitted the former better than the latter. The pseudo-first-order kinetic model, pseudo-second-order kinetic model and intraparticle diffusion model were used to describe the kinetic data, but the pseudo-second-order kinetic model was the best. The thermodynamic parameter ΔG0 were calculated, the negative ΔG0 values of uranium (VI) at different temperatures confirmed the adsorption processes were spontaneous.  相似文献   

8.
The rates of accumulation and subsequent loss of stable cesium (133Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of 133Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg−1 d−1 dry mass) and a loss rate parameter k (d−1) were estimated for each organism using time-series measurements of 133Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (Cr). The maximum 133Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The Cr based on dry mass for plankton and C. punctipennis were 1220 L kg−1 and 5570 L kg−1, respectively, and were less than the Cr of 8630 L kg−1 for periphyton and 47,700 L kg−1 for H. trivolvis. Although the Cr differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the Cr for the mostly nonpiscivorous L. macrochirus of 22,600 L kg−1 was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg−1. Although the Cr for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum 133Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides.  相似文献   

9.
The south east basin of France shelters deep CO2 reservoirs often studied with the aim of better constraining geological CO2 storage operations. Here we present new soil gas data, completing an existing dataset (CO2, 222Rn, 4He), together with mineralogical and physical characterisations of soil columns, in an attempt to better understand the spatial distribution of gas concentrations in the soils and to rule on the sealed character of the CO2 reservoir at present time.Anomalous gas concentrations were found but did not appear to be clearly related to geological structures that may drain deep gases up to the surface, implying a dominant influence of near surface processes as indicated by carbon isotope ratios. Coarse grained, quartz-rich soils favoured the existence of high CO2 concentrations. Fine grained clayey soils preferentially favoured the existence of 222Rn but not CO2. Soil formations did not act as barriers preventing gas migrations in soils, either due to water content or due to mineralogical composition. No abundant leakage from the Montmiral reservoir can be highlighted by the measurements, even near the exploitation well. As good correlation between CO2 and 222Rn concentrations still exist, it is suggested that 222Rn migration is also CO2 dependent in non-leaking areas - diffusion dominated systems.  相似文献   

10.
This study investigates the influence of biological and environmental factors on the concentrations of perfluoroalkyl acids (PFAAs) in a top predator; the American mink. Perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS) and perfluoroalkyl carboxylates (PFCAs) with C8–C13 perfluorinated carbon chains were analyzed in livers from wild male mink liver (n = 101) from four areas in Sweden representing two inland environments (rural and highly anthropogenic, respectively) and two different coastal environments. Mean PFOS concentrations were 1250 ng/g wet weight and some mink from the urban inland area had among the highest PFOS concentrations ever recorded in mink (up to 21 800 ng/g wet weight). PFBS was detected in 89% of the samples, but in low concentrations (mean 0.6 ng/g ww). There were significant differences in PFAA concentrations between the geographical areas (p < 0.001–0.01). Age, body condition and body weight did not influence the concentrations significantly, but there was a seasonal influence on the concentrations of perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnDA) (p < 0.01 and p < 0.05, respectively), with lower concentrations in autumn samples than in samples taken in the winter and spring. It is thus recommended to take possible seasonal differences into account when using mink exposure data. The overall results suggest that the mink is a suitable sentinel species for assessing and monitoring environmental levels of PFAAs.  相似文献   

11.
Carbon dioxide (CO2) emission has drawn a great attention in recent years all over the world, and it plays a very important role in the process of global warming. The off-road equipment, which includes construction equipment, accounted for 7.5% emission of CO2. The objective of this article is to propose a groundwork for a methodology that can be used to estimate the total fuel use and CO2 emissions from construction equipment activities based on its productivity rate. Currently, there is not a methodology or technique for estimating productivity, fuel use and emissions at once. The multiple linear regression analysis has successfully modelled the productivity rate and good to be used as a benchmark for estimating fuel use and CO2 emissions from various types of construction equipment performing earthwork activities. The proposed methodology will help the contractor to estimate the total expected pollutant emissions for the project, which would be valuable information for a preliminary environmental assessment of the project. By using construction plans and specifications, the methodology and tool presented in this research can be used to estimate cost, fuel use and emissions from commercial, residential, industrial or heavy highway. By the proposed approach, it is possible to develop new fuel use and emissions inventories for construction industry in general.  相似文献   

12.
The influence of long-term exposure of model plantations at elevated atmospheric CO2 (550 ppm) on soil respiration under natural conditions has been studied using an automated Free-Air CO2 Enrichment (FACE) system at the Hokkaido University, Japan. In the course of the experiment, an attempt has been made to simulate the effect of forthcoming climate change on the process of CO2 emission from different soil types.  相似文献   

13.
The indoor and outdoor air quality of two staff quarters of Hong Kong Polytechnic University at Tsim Sha Tsui East (TSTE) and Shatin (ST) were investigated. The air sampling was carried out in winter for about two months starting from January to February of 1996. Fifteen flats from each staff quarter were randomly selected for indoor/outdoor air pollutant measurements. The pollutants measured were NOx, NO, NO2, SO2, CO, and O3. The variations of pollutant concentrations between indoor and outdoor air were investigated on weekday mornings, weekday evenings, weekend mornings, and weekend evenings. All indoor/outdoor pollutant concentrations measured did not exceed the ASHRAE/NAAQS standard. The carbon monoxide concentrations indoors were systemically higher than those outdoors at the TSTE and the ST quarters, both on weekdays and Sunday, which indicates there are CO sources indoors. Except for CO, the indoor levels of other pollutants (NOx, NO, NO2, SO2, and O3) are lower than those outdoors. There was a significant correlation (P < 0.05) between indoor and outdoor concentrations for SO2 and O3 at both the TSTE and the ST quarters. Except for O3, the mean concentrations of all the pollutants in the TSTE quarters, both indoor and outdoor, were higher than that of the ST quarters in all sampling periods. All indoor and outdoor O3 levels were lower at the TSTE quarters than those at the ST quarters. The O3 ratios of TSTE/ST were 0.72 outdoor and 0.79 indoor. This can be explained by the NO titration reaction through NO conversion to NO2.  相似文献   

14.
Determined the contribution of root derived CO2 efflux to total CO2 efflux (including root and non-root derived CO2 efflux) is import to grope the mechanism of CO2 efflux, however, becaused of ‘rhizoshere priming effect’ (RPE), it is difficult to achieve in practice. In this study, we attempted to estimate the RPE via comparing basal soil respiration (Rb) achieved by two different methods namely, y-intercept regression and direct bare plot approach in an arid cotton field, central Asia. On the basis of the y-intercept of linear regressions between below-ground respiration (BGR) and root biomass, Rb was indirectly calculated. Comparing with the first approach, the second approach involved direct measurements of soil respiration from bare plots. Rb estimated by y-intercept method contained the component of RPE whereas direct bare plot did not. We found that RPE showed a phenological trend with highest value in flowering stage at 0.145 g CO2 m–2 h–1 and lowest at budding stage (0.007 g CO2 m–2 s–1), even after the data had been corrected for the influence of soil temperature. We concluded that RPE needed to be considered when Rb was estimated by y-intercept approach.  相似文献   

15.
An incubation experiment was performed to study the effect of sewage sludge on microbial respiration and nutrient mineralization in a sandy soil as an indication of its effects on soil biological properties and nutrient transformation. Sewage sludge was amended with a sandy soil at 0, 25, 50, 150 and 350 g kg−1 fresh weight. An increase in the sludge amendment rate caused an increase in both pH and electrical conductivity (EC). However, pH decreased while EC increased and then decreased along the incubation time. Nevertheless salinity and heavy metal contents of the soil sludge mixture were all within the safety guidelines. Soluble NH4+, NO32− and PO32− increased after amending the soil with sewage sludge, but increasing the application rate to 350 g kg−1 of sludge decreased the N and P mineralization efficiency and created an adverse effect on nitrification. The daily CO2 evolution pattern was the same in all treatments that CO2 evolution increased initially and then decreased till the end of the incubation period. All the treatments had peak CO2 evolution at day 7, except for the soil amended with 350 g kg−1 of sludge which had peak CO2 evolution at day 2. Similarly, the percentage of C-mineralization decreased with an increase in sludge amendment rate. The present experiment indicated that an application rate of 50–150 g kg−1 sludge for sandy soil would have the optimal beneficial effect on the soil in terms of microbial activity and nutrient transformation.  相似文献   

16.
A spatial comparison of pollutant concentrations within the residential environment is undertaken, comparing pollutant concentrations from three indoor sampling locations (zones). The indoor air quality base was obtained from sampling the indoor air of 12 residential sites and two office buildings in the metropolitan Boston area. Each residential site was monitored continuously for two weeks, and data were reduced into hourly averages. Interzonal comparisons of the mean of hourly averages, 24-h averages, and daily maximum hourly concentrations were made at all sites. Linear regressions were computed between daily maximum hourly concentrations and mean 24-h concentrations of NO, NO2, and CO for kitchens to determine whether maximum hourly concentrations could be predicted from the 24-h concentration. These pollutants show interzonal statistical differences in residences with gas-fired cooking facilities but not in residences with electric cooking facilities. It was determined that, while one indoor sampling zone is not sufficient to specify indoor pollutant concentration maxima in residences having indoor sources of pollution, the daily mean of hourly pollutant concentrations obtained from one indoor zone can adequately describe the indoor environment. In addition, the maximum indoor hourly concentration for NO, NO2, and CO can be estimated for residences with all electric facilities, by using the mean 24-h concentration. The reliability of similar estimates for NO, NO2, and CO in residences with unvented gas appliances is reduced because of substantially more scatter in the paired data point, particularly at higher pollutant concentrations.  相似文献   

17.
A comparative assessment of the biological properties of chernozem soils in agro- and biogeocenoses has been made by determining the rates of basal and substrate-induced soil respiration and using these data to calculate ecophysiological indices characterizing the potential and stability of soil microbial biomass. The results show that the rate of CO2 emission and the contents of microbial biomass carbon in agriculturally exploited chernozem soils have decreased by factors of 3 and 2.6, respectively. The values of microbial metabolic quotients are indicative of medium-to-strong disturbance to the stability of microbial communities in chernozem soils of agrocenoses.  相似文献   

18.
Persistent organic pollutants (POPs) accumulated in human tissues may pose a risk for human health by interfering with the endocrine system. This study establishes a new link between actual human internal POP levels and the endocrine active dose in vitro, applying partitioning-controlled dosing from silicone to the H295R steroidogenesis assay: (1) Measured concentrations of POPs in silicone breast implants were taken from a recent study and silicone disks were loaded according to these measurements. (2) Silicone disks were transferred into H295R cell culture plates in order to control exposure of the adrenal cells by equilibrium partitioning. (3) Hormone production of the adrenal cells was measured as toxicity endpoint. 4-Nonylphenol was used for method development, and the new dosing method was compared to conventional solvent-dosing. The two dosing modes yielded similar dose-dependent hormonal responses of H295R cells. However, with the partitioning-controlled freely dissolved concentrations (Cfree) as dose metrics, dose–response curves were left-shifted by two orders of magnitude relative to spiked concentrations. Partitioning-controlled dosing of POPs resulted in up to 2-fold increases in progestagen and corticosteroid levels at Cfree of individual POPs in or below the femtomolar range. Silicone acted not only as source of the POPs but also as a sorption sink for lipophilic hormones, stimulating the cellular hormone production. Methodologically, the study showed that silicone can be used as reference partitioning phase to transfer in vivo exposure in humans (silicone implants) to in vitro assays (partition-controlled dosing). The main finding was that POPs at the levels at which they are found in humans can interfere with steroidogenesis in a human adrenocortical cell line.  相似文献   

19.
Microbiological quality of surface waters can be affected by microbial load in runoff from grazing lands. This effect, with other factors, depends on the survival of microorganisms in animal waste deposited on pastures. Since temperature is a leading environmental parameter affecting survival, it indirectly impacts water microbial quality. The Q10 model is widely used to predict the effect of temperature on rates of biological processes, including survival. Objectives of this work were to (i) evaluate the applicability of the Q10 model to Escherichia coli inactivation in bovine manure deposited on grazing land (i.e., cowpats) and (ii) identify explanatory variables for the previously reported E. coli survival dynamics in cowpats. Data utilized in this study include published results on E. coli concentrations in natural and repacked cowpats from research conducted the U.S. (Virginia and Maryland), New Zealand, and the United Kingdom. Inspection of the datasets led to conceptualizing E. coli survival (in cowpats) as a two-stage process, in which the initial stage was due to growth, inactivation or stationary state of the population and the second stage was the approximately first-order inactivation. Applying the Q10 model to these datasets showed a remarkable similarity in inactivation rates, using the thermal time. The reference inactivation rate constant of 0.042 (thermal days) 1 at 20 °C gave a good approximation (R2 = 0.88) of all inactivation stage data with Q10 = 1.48. The reference inactivation rate constants in individual studies were no different from the one obtained by pooling all data (P < 0.05). The rate of logarithm of the E. coli concentration change during the first stage depended on temperature. Duration of the first stage, prior to the first-order inactivation stage and the initial concentration of E. coli in cowpats, could not be predicted from available data. Diet and age are probable factors affecting these two parameters however, until their environmental and management predictors are known, microbial water quality modeling must treat them as a stochastic source of uncertainty in simulation results.  相似文献   

20.
The effects of air pollution on health have been studied worldwide. Given that air pollution triggers oxidative stress and inflammation, it is plausible that high levels of air pollutants cause higher number of hospitalisations. This study aimed to assess the impact of air pollution on the emergency hospitalisation for respiratory disease in Rio de Janeiro, Brazil. The study was divided in two parts: Part I specifically addressing the air pollution assessment and Part II addressing the health assessment. Accordingly, this Part II aimed to estimate the association between the concentrations of PM10, SO2 and CO observed in Rio de Janeiro and the number of emergency hospitalisations at a central hospital due to respiratory diseases. The pollutant concentrations were measured at two different sites in Rio de Janeiro, but the excess relative risks were calculated based on the concentrations observed at one of the sites, where limits were generally exceeded more frequently, between September 2000 and December 2005. A time series analysis was performed using the number of hospitalisations, divided in three categories (children until 1 year old, children aged between 1 and 5 years old and elderly with 65 years old or more) as independent variable, the concentrations of pollutants as dependent variables and temperature, relative humidity, long term trend, and seasonality as confounders. Data were analysed using generalised additive models with smoothing for some of the dependent variables. Results showed an excess risk of hospitalisation for respiratory disease higher than 2% per 10 μg m 3 increase in PM10 concentrations for children under 5 years old, of 2% per 10 μg m 3 increase in SO2 for elderly above 65 years old and around 0.1% per 10 μg m 3 increase in CO for children under 1 year and elderly. Other studies have found associations that are in agreement with the results achieved in this study.The study suggests that the ambient levels of air pollutants experienced in Rio de Janeiro between 2000 and 2005 were linked to the number of hospitalisations for respiratory diseases among children and elderly.  相似文献   

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