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1.
In 1971 an orientating study was started concerning the ground-level concentrations of sulphate and sulphuric acid relative to sulphur dioxide. In order to achieve a more selective method for the determination of sulphuric acid, the separation of sulphuric acid from sulphates by isopropanol was used. After separation sulphuric acid and sulphate are determined spectrophotometrically with barium chloranilate. Air samples were taken with air samplers using 0.8 μm pore cellulose triacetate filters. In the winter 1971–1972 at Arnhem the ratio sulphate/total sulphur correlated significantly with the relative humidity and decreased with increasing SO 2 concentration. The mean value of the ratio was 12.5% at a mean SO 2 concentration of 71 μg m −3. The mean ratio H 2SO 4/total sulphur was 0.34%. In summer 1972, with a mean ratio sulphate/total sulphur of 36.8% at a mean SO 2 level of 8 μg m −3, there was a correlation between sulphate and NH 3 on days with a relative humidity >80%; this suggests an influence on the oxidation rate by NH 3. The amounts of NH 4+, SO 42−, and NO 3− give rise to the supposition that the greater part of sulphate and nitrate is present as ammonium salts. The measurements were continued at Arnhem and Rotterdam (Rijnmond area) in 1973, 1975 and 1976. In these years there was a strong decrease in SO 2 concentration with a less stronger decrease in sulphate concentration. This together with the uniform distribution of sulphates in The Netherlands indicates that the sulphate level is caused mainly by long range transport. There was no increased reactivity in the formation of sulphates in the industrial Rijnmond area as compared to the eastern part of The Netherlands. Increased H 2SO 4 concentrations occurred as a result of transport of aerosols over sea by western winds. In summer 1976 there were significant correlations between both sulphate and nitrate with ozone at all the measuring stations, from which the existence of photochemical reactions over large areas can be concluded. 相似文献
2.
Nitrogen oxides emissions in Asia during the period 1990–2020 due to anthropogenic activity are presented. These estimates are based on the RAINS-ASIA methodology (Foell et al., 1995, Acid Rain and Emission Reduction in Asia, World Bank), which includes a dynamic model for energy forecasts, and information on 6 energy sectors and 9 fuel types. The energy forecasts are combined with process emission factors to yield NO x emission estimates at the country level, the regional level, and on a 1 degree by 1 degree grid. In 1990 the total NO x emissions are estimated to be ∼19 Tg NO 2, with China (43%), India (18%) and Japan (13%) accounting for 75% of the total. Emissions by fuel are dominated by burning of hard coal and emissions by economic activity are dominated by the power, transport, and industrial sectors. These new estimates of NO x emissions are compared with those published by Hameed and Dignon (1988, Atmospheric Environment 22, 441–449) and Akimoto and Narita (1994, Atmospheric Environment 28, 213–225). Future emissions under a no-further-control scenario are also presented. During the period 1990–2020 the NO x emissions increase by 350%, to ∼86 Tg NO 2. The increase in NO x emissions by sector and end-use varies between countries, but in all countries this increase is strongest in the power and transport sectors. These results highlight the dynamic nature of energy use in Asia, and the need to take the rapid growth in NO x emissions in Asia into account in studies of air pollution and atmospheric chemistry. 相似文献
3.
The present study assessed the DNA damage in environmentally exposed volunteers living in seven municipalities in an industrial coal region, through the use of the comet assay with blood cells and the micronucleus test with buccal cells. Blood and buccal smears were collected from 320 male volunteers living in seven cities inserted in a coal region. They were ages of 18 and 50 years and also completed a questionnaire intended to identify factors associated with DNA damage through a Poisson regression analysis. The comet assay detected significant differences in DNA damage in volunteers from different municipalities, and neighboring cities (Pedras Altas, Aceguá, and Hulha Negra) had a higher level of DNA damage in relation to control city. Some of the risk factors associated with identified DNA lesions included residence time and life habits. On the other hand, the micronucleus test did not identify differences between the cities studied, but the regression analysis identified risk factors such as age and life habits (consumption of mate tea and low carbohydrates diet). We conclude that there are differences in the DNA damage of volunteers from different cities of the carboniferous region, but the presence of micronuclei in the oral mucosa does not differ between the same cities. Furthermore, we alert that some related factors may increase the risk of genotoxicity, such as residence location and time, and living and food habits. Finally, we suggest the need for continuous biomonitoring of the population, as well as for investing in health promotion in these vulnerable populations. 相似文献
4.
Selected organonitrogen, organophosphorus and organochlorine pesticides have been determined in precipitation samples collected at 10 sites in the Gdańsk region (northern Poland) over a period of one year (1998). Compounds which were detected most often included simazine (0.11-5.80 ng/l), fenitrothion (0.1-2.10 ng/l), chlorfenvinfos (0.1-1.30 ng/l), gamma-HCH (0.012-5.06 ng/l), heptachlor epoxide (0.05-3.28 ng/l) and aldrin (0.02-3.28 ng/l). The pesticide concentrations in precipitation samples revealed seasonal fluctuations, with higher concentrations observed during the application periods (June and July). The concentrations observed were also affected by the inflow of polluted air masses from the southwest. The total pesticide concentration in the precipitation samples was strongly related to the abundance of green areas in the vicinity of the sampling sites. A weak correlation was also found between the total concentration of organonitrogen and organophosphorus pesticides, and the total concentration of organochlorine pesticides in the samples collected. 相似文献
5.
China, as a fast growing fossil-fuel-based economy, experiences increasing levels of air pollution. To tackle air pollution, China has taken the first steps by setting emission–reduction targets for nitrogen oxides (NO x) and sulphur dioxide (SO 2) in the 11th and 12th Five Year Plans. This paper uses two models—the Energy–Environment–Economy Model at the Global level (E3MG) and the global Chemistry Transport Model pTOMCAT—to test the effects of these policies. If the policy targets are met, then the maximum values of 32 % and 45 % reductions below ‘business as usual’ in the monthly mean NO x and SO 2 concentrations, respectively, will be achieved in 2015. However, a decrease in NO x concentrations in some highly polluted areas of East, North-East and South-East China can lead to up to a 10% increase in the monthly mean concentrations in surface ozone in 2015. Our study demonstrates an urgent need for the more detailed analysis of the impacts and designs of air pollution reduction guidelines for China. 相似文献
6.
Dissolved organic carbon (DOC), surface active substances (SAS) and copper complexing capacity (CuCC) were studied in bulk precipitations collected periodically from 2003 to 2007 in the continental city of Croatia (Zagreb: n = 27) and in the city at the Adriatic coast (?ibenik: n = 38). DOC concentrations (Zagreb: 0.67–4.03 mgC/L with average concentration of 1.93 ± 0.76 mgC/L; ?ibenik: 0.44–4.13 mgC/L with average concentration of 1.83 ± 0.83 mgC/L) are similar to those measured in other samples of continental rainwater in the northern hemisphere. The concentrations of SAS in samples from Zagreb ranged from 0.055 to 0.45 eq. Triton-X-100 mg/L with average concentration of (0.14 ± 0.06) eq. Triton-X-100 mg/L. SAS fractions were of a similar range in ?ibenik (0.02–0.60 eq. Triton-X-100 mg/L) with an average concentration of 0.11 ± 0.06 eq. Triton-X-100 mg/L. However, the lowest values of SAS (between 0.02 and 0.04 eq. Triton-X-100 mg/L) were observed only in ?ibenik (27%). We have estimated that the higher pH values were responsible for lower surface activity of organic matter in bulk samples from ?ibenik. DOC may form complexes that control the transport and solubility of heavy metals in natural water. CuCC measured in ?ibenik in the range 0.066–1.4 μM Cu 2+ was in general higher, compared to the one in Zagreb (0.010–0.586 μM Cu 2+) which is the result of biogenically driven organic contribution to the precipitation, especially in the warmer period of the year. 相似文献
7.
Environmental Science and Pollution Research - Sandy cropland ecosystems are major terrestrial ecosystems in semi-arid regions of northern China’s Horqin Sandy Land, where they play an... 相似文献
8.
Reclaiming abandoned and unmaintained roads, built originally for forestry and mineral extraction, is an important part of ecological restoration, because the roads running through natural habitats cause fragmentation. The roads can be reclaimed in a passive way by blocking access to the road, but successful seedling recruitment may require additional management due to the physical constraints present at the road. We established a full factorial study to compare the effects of three road reclaiming measures, namely ripping, creation of safe sites by adding mulch and pine seed addition, on soil processes, recovery of understorey vegetation and seedling recruitment in three conservation areas in eastern Finland. We surveyed soil organic matter, frequency and cover of plant functional types, litter and mineral soil, and number of tree seedlings. The soil organic matter was, on average, 1.3-fold in the 50-cm-deep ripping treatment relative to unripped and 20-cm-deep ripping treatments. The germination and survival of deciduous seedlings and grass establishment were promoted by adding mulch. The addition of pine seeds counteracted the seed limitation and enhanced the regeneration of trees. The treatment combination consisting of ripping, adding mulch and pine seed addition enhanced the vegetation succession and tree-seedling recruitment most: the cover of grasses, herbs and ericaceous dwarf shrubs was 1.3–7.6-fold and the number of coniferous tree seedlings was 3.4–7.1-fold relative to the other treatment combinations. Differences between short-term (1–3 years) and longer-term (6 years) results indicate the need for a sufficient observation period in road reclamation studies. 相似文献
9.
The toxicities and bioavailabilities of total mercury (THg) and methylmercury (MeHg) in aquatic systems have made them the subjects of recent research. In this study, we collected a lake sediment core from Ny-Ålesund in Svalbard and analyzed the distributions of THg and MeHg in the sediments. The increased trend of THg was caused by anthropogenic contamination since the 14th century through long-range transportation, especially after the industrial era. However, the peak values of Hg in surface sediment samples could be explained by the increased algal scavenging process in recent decades. All the biogeochemical proxies (e.g., pigments and diatom biomass) revealed recent sharp increases in aquatic primary production due to the current climate warming. Rock-Eval analyses indicated that algal-derived organic matter took up a large portion, and quantitative calculation showed that 89.6-95.8% of the Hg in post-1950 could be explained by scavenging. The distribution of MeHg has a close relationship with total Hg and organic matter. The oxidation-reduction condition is one of the possible factors affecting the methylation rates in H2 lake sediments. Higher algal productivity and organic matter actually led to the increased trend of methylation in the uppermost sediment. This study supports some new key hypotheses on climate-driven factors affecting Hg and MeHg cycling in High Arctic lake sediments. 相似文献
10.
A parametric study on the relative effect of various electrical forces on aerosol filtration in fibrous and granular filters is presented. The paper covers the engineering practical range of the electrical field intensity and dust particle sizes. Coulombic attraction has the widest range of application but other forces may dominate in some specific applications. 相似文献
11.
The increasing concentrations impact (0.02, 0.2 and 2 mg L −1) of a Sterol Biosynthesis Inhibitor (SBI) fungicide, propiconazole, was evaluated on development and sterol metabolism of two non-target organisms: mycorrhizal or non-mycorrhizal transformed chicory roots and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare using monoxenic cultures. In this work, we provide the first evidence of a direct impact of propiconazole on the AMF by disturbing its sterol metabolism. A significant decrease in end-products sterols contents (24-methylcholesterol and in 24-ethylcholesterol) was observed concomitantly to a 24-methylenedihydrolanosterol accumulation indicating the inhibition of a key enzyme in sterol biosynthesis pathway, the sterol 14α-demethylase like in phytopathogenic fungi. A decrease in end-product sterol contents in propiconazole-treated roots was also observed suggesting a slowing down of the sterol metabolism in plant. Taken together, our findings suggest that the inhibition of the both AM symbiotic partners development by propiconazole results from their sterol metabolism alterations. 相似文献
12.
Industrial activity is one of the main sources of ambient pollution in developed countries. However, research analyzing its effect on birth outcomes is inconclusive. We analyzed the association between proximity of mother’s municipality of residence to industries from 24 different activity groups and risk of very (VPTB) and moderate (MPTB) preterm birth, very (VLBW) and moderate (MLBW) low birth weight, and small for gestational age (SGA) in Spain, 2004–2008. An ecological study was defined, and a “near vs. far” analysis (3.5 km threshold) was carried out using Hierarchical Bayesian models implemented via Integrated Nested Laplace Approximation. VPTB risk was higher for mothers living near pharmaceutical companies. Proximity to galvanization and hazardous waste management industries increased the risk of MPTB. Risk of VLBW was higher for mothers residing near pharmaceutical and non-hazardous or animal waste management industries. For MLBW many associations were found, being notable the proximity to mining, biocides and animal waste management plants. The strongest association for SGA was found with proximity to management animal waste plants. These results highlight the importance of further research on the relationship between proximity to industrial sites and the occurrence of adverse birth outcomes especially for the case of pharmaceutical and animal waste management activities. 相似文献
13.
In this analysis, we characterize urban and rural ozone (O 3) trends across the US for the periods 1980–2008 (29 years) and 1994–2008 (15 years) using three exposure metrics, which summarize daily O 3 concentrations to reflect different ways O 3 may affect human health and vegetation. We observe that a statistically significant trend at a specific monitoring site, using one exposure metric, does not necessarily result in a similar trend using the other two metrics. The two most common trends among the monitoring sites are either a continuation of negative trending over the 29-year period or a shift from negative to no trend status, indicating a leveling off of the trending. Very few sites exhibit statistically significant increases in the exposure indices. In characterizing the statistically significant changes in the distribution of hourly average O 3, we observe subtle statistically significant changes in the lower part of the distribution (i.e., below 50 ppb) that are not necessarily captured by the trending patterns associated with the three exposure metrics. Using multisite data from 12 metropolitan cities, we find that as the frequency of higher hourly average concentrations is reduced, the lower hourly average concentrations also move upward toward the mid-level values. The change in the number of the hourly average concentrations in the lower range is consistent with decreased NO scavenging. We recommend assessing possible subtle shifts in O 3 concentrations by characterizing changes in the distribution of hourly average concentrations by month. Identifying statistically significant monthly changes in the mid- and low-level hourly average concentrations may provide important information for assessing changes in physical processes associated with global climate change, long-range transport, and the efficacy of models used for emission and risk reductions. Our results indicate that it is important to investigate the change in the trending pattern with time (e.g., moving 15-year trending) in order to assess how year-to-year variability may influence the trend calculation. 相似文献
14.
Ozone concentrations were measured at two (urban and a rural) sites near the city of Málaga (Spain). The aim of this study was to determine the daily, monthly and seasonal variation patterns of ozone concentrations at both sites and to study the possible regional influences. The daily variations mostly have the usual features with the afternoon maximum and the night minimum being more pronounced in the urban area. The average monthly concentrations throughout the year start to increase in March reaching their maximum values in July for the urban site. However, in the rural area, the monthly variations are smaller reaching their maximum value in June. The hourly evolution of the ozone concentrations in both sampling sites is well defined in spring and summer and not so well defined in autumn and winter. Taking into account the four seasons, the rural concentrations are higher than the urban ones. Summer is the season when there are similar concentrations at both sampling sites. Average hourly summer afternoon ozone for the hours 12:00-20:00 LST exceeded the 110 microg m(-3) European Union guidelines for human health for 8 h ozone exposure at the urban and rural sites. 相似文献
15.
Abstract Meteorologically adjusted ozone (O 3) concentrations during five recent O 3 seasons (1998-2002) were computed for six Kentucky metro areas using a nonlinear regression model originally developed for forecasting ground-level O 3 concentrations. The meteorological adjustment procedure was based on modifying actual measured O 3 concentrations according to model-predicted responses to climate departures with respect to a reference year. For all six Kentucky metro areas, meteorologically adjusted O 3 concentrations declined over the five-year period. The linear best-fit rate of decline in mean adjusted O 3 concentrations ranged from 0.9 to 2.6 ppb/yr for these metro areas; the average rate of decline was 1.6 ppb/yr. The rates of decline in meteorologically adjusted extreme value (e.g., 95th percentile) concentrations were approximately the same, but there is greater statistical uncertainty concerning the extreme value trends. 相似文献
16.
Annual and seasonal trends were discussed for precipitation chemistry in Japan on the basis of a nationwide monitoring network by Japan Environment Agency. For this analysis, 17 sites, selected from the 23 network sites after evaluation of data completeness for the present purpose, were grouped into four areas in terms of the sea which could characterize each area: the Pacific Ocean, the Japan Sea, the Seto Inland Sea and the East China Sea areas. Major ion concentrations at each site were subjected to least-squares multiple regression analysis, and discussion was principally focused on the area-groups. Each area showed significant ( p<0.05) decreasing trends in non-sea-salt sulfate (nss-SO 42−) concentrations with the annual mean change rate of −3.0% yr −1, whereas no significant trends were detected for NO 3− at 59% of the sites. Ammonium (NH 4+) showed significant increasing trends for 35%, and decreasing trends for 18% of the sites; and, the maximum change rate of 3.8% yr −1 was recorded in the Pacific Ocean area. Non-sea-salt calcium (nss-Ca 2+) concentrations significantly decreased in northern and some industrialized areas. Both the annual cycle-amplitudes and effects of precipitation amounts were significant for the four ions at almost all sites. The maximum concentrations of nss-SO 42− and -Ca 2+ occurred from winter to spring at most sites. The seasons when the maximum concentrations of NO 3− and NH 4+ occurred, were found to differ from area to area. Furthermore, the trends in precipitation nss-SO 42−, and NO 3− were qualitatively consistent with those of anthropogenic emissions of SO 2, and NO x in Japan, respectively. 相似文献
17.
The level of some OCPs in human and cow milk collected from Asendabo, Serbo and Jimma in South-West Ethiopia were analyzed using GC–ECD. Results of the analysis indicated that all samples contained detectable quantities of p, p′-DDT and its metabolites, p, p-DDE and p, p-DDD, but none of the other OCPs analyzed. Mean levels of total DDT in the human and cow milk samples in the three areas were 12.68 and 0.389 μg g ?1 respectively. The distributions of p, p-DDT, p, p-DDE and p, p-DDD in the human milk samples from the three locations followed the same trend in which the proportion of p, p-DDT was the highest in all the three cases, comprising 55–71% of total DDT, followed by p, p-DDE, 26–39%, and the least, p, p-DDD of 2–5%. The mean ratio of DDT/DDE concentration for the three areas was calculated to be 2.01. This value was much higher than the values reported from other countries in earlier studies and indicates the existence of a higher quantity of DDT from a fresh input in the three study areas. The mean estimated daily intake of DDT by infants from mother’s milk in the three locations was found to be 62.17 μg kg ?1 body weight, which is about three times higher than the acceptable daily intake set by WHO/FAO for total DDT, 20 μg kg ?1 of body weight. This alarmingly high daily intake value is a cause for concern, since children are highly susceptible to effects from such environmental contaminants. The study has revealed that people in the study areas are facing exposure to DDT from recent use. The observed contamination of mother’s milk and the possible transfer of the contaminant from mother to child is an obvious risk associated with breast-feeding in the study areas and possibly in other parts of the country too. 相似文献
18.
Environmental Science and Pollution Research - The fact is that output volatility and carbon dioxide (CO2) emissions move together over the period. This empirical study examines the dynamic effect... 相似文献
19.
Introduction The concentration of a pharmaceutical found in the environment is determined by the amount used by the patient, the excretion
and metabolism pattern, and eventually by its persistence. Biological degradation or persistence of a pharmaceutical is experimentally
tested rather late in the development of a pharmaceutical, often shortly before submission of the dossier to regulatory authorities. 相似文献
20.
The total (wet and dry) deposition of trace and major elements from the atmosphere was measured throughout 1 year at twelve sampling stations in the ‘Campo de Gibraltar’, an industrial zone where there are important residential areas. The data included in this paper have contributed to a better knowledge of the regional deposition of Al, Cr, Fe, Mn, Ni, Pb, V, Zn, Ca, Mg, K, Na, Cl −, NH 4+, NO 3−and SO 42− in both soluble and insoluble form. 相似文献
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