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31.
This study aimed at cross-border mapping metal loads in mosses in eight European countries in 1990, 1995, and 2000 and at investigating confounding factors. Geostatistics was used for mapping, indicating high local variances but clear spatial autocorrelations. Inference statistics identified differences of metal concentrations in mosses on both sides of the national borders. However, geostatistical analyses did not ascertain discontinuities of metal concentrations in mosses at national borders due to sample analysis in different laboratories applying a range of analytical techniques. Applying Classification and Regression Trees (CART) to the German moss data as an example, the local variation in metal concentrations in mosses were proved to depend mostly on different moss species, potential local emission sources, canopy drip and precipitation.  相似文献   
32.
Riparian buffers are known to mitigate hydrologic losses of nutrients and other contaminants as they exit agricultural fields. The vegetation of riparian buffers can also trap atmospheric contaminants, and these pollutants can subsequently be delivered via rain to the riparian buffer floor. These processes, however, are poorly understood especially for pesticide residues. Therefore, we conducted a four‐year study examining stemflow and throughfall to a riparian buffer which was adjacent a cultured Zea mays field treated with atrazine and metolachlor. Stemflow is rain contacting the tree canopy traveling down smaller to larger branches and down the tree trunk, whereas throughfall is rain that may or may not contact leaves and branches and reaches the earth. Stemflow concentrations of the herbicides were larger than throughfall concentrations and accounted for 5‐15% of the atrazine and 6‐66% of the metolachlor depositional fluxes under the canopy. Larger depositional fluxes were measured when leaves were more fully emerged and temperatures and humidity were elevated. Rain collected outside the riparian buffer on the field side and on the back side revealed the trees trapped the herbicide residues. Herbicide loading to the riparian buffer stream was found to be linked to tree canopy deposition and subsequent washoff during rain events. These results indicate that in agricultural areas canopy washoff can be an important source of pesticides to surface waters.  相似文献   
33.
Several hundred chemical compounds were found in workroom environments in the rubber industry, but most of the published exposure data relate to the production of tyres; information from the "non-tyre" sections are very limited, if any. This study was carried out to identify chemical substances and measure their air concentrations in the repair shop of a brown coal mine in which damaged rubber conveyor belts were repaired. GC-MS and HPLC analysis of stationary air samples resulted in identification of aliphatic and aromatic hydrocarbons to C12, PAHs, alcohols, phenols, ketones, heterocyclic nitrogen and sulfur compounds. Quantitative evaluation of occupational exposure included determination of organic compound vapours collected on charcoal (GC-MSD), polycyclic aromatic hydrocarbons (HPLC), N-nitrosoamines and other amines (GC-NPD) and DNPH derivatives of aldehydes (HPLC) in the breathing zone of workers representing all job titles. The concentrations of investigated compounds were very low. Carcinogenic substances: N-nitrosoamines, benzene, PAHs were not present in workroom air in concentrations exceeding limits of detection of the analytical methods being applied; concentrations of methylisobutylketone, tetrachloroethylene, naphtha, aromatic hydrocarbons, phthalates and aldehydes were much lower than the respective occupational exposure limit values. The results indicate much lower exposure than that reported in the production of tyres and other fabricated rubber products.  相似文献   
34.
The aim of this work was to assess dietary risk resulting from consumption of polycyclic aromatic hydrocarbons (PAHs) with tea infusions. To this end, levels of 28 PAHs in black, green, red and white teas available on the Polish retail market have been assessed. Profiles and correlation between concentrations of individual PAHs have been identified. A model study on transfer of PAHs from tea leaves into tea preparations has been conducted. Relatively high concentrations of 28 evaluated PAHs have been found in 58 tested samples of black, green, red and white teas sampled on the Polish retail market. Total concentration ∑28PAH ranged from 57 to 696 µg kg?1 with mean 258 µg kg?1 (dry tea leaves). The most mature tea leaves fermented to a small degree contained relatively the highest PAH levels among all four tested tea types. Relatively low PAH transfer rates into tea infusions and limited volumes of the consumed tea keep the risks associated with PAH dietary intake at a safely low level.

The worst-case scenario dietary intake values were 7.62/0.82/0.097 ng kg?1 b.w. day?1 (estimated on the basis of the maximum found concentrations 696/113/23 µg kg?1 and maximum observed transfer rates 24/16/9%) for ∑28PAH/∑PAH4/B[a]P, respectively. MOE values calculated using the above worst case estimates exceeded 700,000 and 400,000 (BMDL10 0.07 and 0.34 mg kg?1 b.w. day?1) for B[a]P and PAH4, respectively. Both B[a]P and PAH4 concentrations may be used as indicators of total PAH concentration in tea leaves; PAH4 slightly better fits low molecular weight PAHs. Several correlations between various PAHs/groups of PAHs have been identified, the strongest one (R2 = 0.92) between PAH4 and EU PAH 15+1.  相似文献   
35.
This study was designed to evaluate the measuring range and lowest limit of detection of Bacillus endospores in the ambient room air when the Sartorius MD8 sampler, and two different culture methods for bacterial enumeration were used. Different concentrations of bioaerosol were generated inside the test chamber filled with either the high-efficiency particulate air (HEPA)-filtered air or with the ambient room air. The detection of endospores in the HEPA-filtered air was achievable: (1) when they were aerosolized at a concentration above 7.56?×?103 CFU/m3 and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 4.00?×?102 CFU/m3 and analyzed with pour plate method. The detection of endospores in the ambient room air was possible: (1) when they were aerosolized at a concentration above 9.1?×?103 CFU/m3 and analyzed with spread plate method, and (2) when they were aerosolized at a concentration above 5.6?×?102 CFU/m3 and analyzed with pour plate method. The microorganisms present in the ambient room air interfere with precise quantification of Bacillus endospores when their concentration is relatively low. The results of this study may be helpful in critical assessment of the results obtained from monitoring the air for bacterial endospores.  相似文献   
36.
The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg?1) and detection (0.0005 mg kg?1) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001–0.5 mg kg?1) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT50 of S-MET calculated according to the first-order kinetics model was 11.1–14.7 days (soil) and 9.6–13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.  相似文献   
37.
Small-holder farmers often develop adaptable agroforestry management techniques to improve and diversify crop production. In the cocoa growing region of Ghana, local knowledge on such farm management holds a noteworthy role in the overall farm development. The documentation and analysis of such knowledge use in cocoa agroforests may afford an applicable framework to determine mechanisms driving farmer preference and indicators in farm management. This study employed 12 in-depth farmer interviews regarding variables in farm management as a unit of analysis and utilized cognitive mapping as a qualitative method of analysis. Our objectives were (1) to illustrate and describe agroforestry management variables and associated farm practices, (2) to determine the scope of decision making of individual farmers, and (3) to investigate the suitability of cognitive mapping as a tool for assessing local knowledge use. Results from the cognitive maps revealed an average of 16 ± 3 variables and 19 ± 3 links between management variables in the farmer cognitive maps. Farmer use of advantageous ecological processes was highly central to farm management (48% of all variables), particularly manipulation of organic matter, shade and food crop establishment, and maintenance of a tree stratum as the most common, highly linked variables. Over 85% of variables included bidirectional arrows, interpreted as farm management practices dominated by controllable factors, insofar as farmers indicated an ability to alter most farm characteristics. Local knowledge use on cocoa production revealed detailed indicators for site evaluation, thus affecting farm preparation and management. Our findings suggest that amid multisourced information under conditions of uncertainty, strategies for adaptable agroforestry management should integrate existing and localized management frameworks and that cognitive mapping provides a tool-based approach to advance such a management support system.  相似文献   
38.
The natural environment of the Carpathian Mountains is one of the richest in Europe in terms of species richness and ecological value. In general, these mountains are well preserved and constitute an important part of Europe's nature resources. The Carpathian area, although divided by political and ethnic frontiers, provides an excellent example of the possibility of protection and conservation of natural and cultural heritage. Natural or seminatural forest ecosystems are the most valuable ecosystems together with man-made meadows and pastures. It is expected that the formerly diverse approaches to nature protection will become unified as the Carpathian countries are incorporated into the European Union. In this paper the various forms of nature protection in the individual Carpathian countries (Czech Republic, Slovakia, Poland, Ukraine and Romania) are described.  相似文献   
39.
The study determined physiological and psychophysical responses to fire fighters' typical activities. Self-reported assessment of the most demanding fire fighting/rescue tasks were collected with a questionnaire. Then 19 voluntary fire fighters performed 3 simulated fire fighting/rescue tasks in protective clothing. Heart rate (HR), blood pressure and energy expenditure were measured; the rating of perceived exertion (RPE) was assessed with the Borg scale. The questionnaires showed that carrying out victims, fire suppression and resuscitation were classified as heavy load; climbing stairs with a hose as moderate load. According to RPE the subjects considered their effort during ladder climbing fairly light and only somewhat harder during stair climbing and carrying out injured people. The study demonstrated that typical fire fighting/rescue tasks were associated with high energy expenditure and imposed considerable cardiovascular stress. The Borg scale appeared not suitable for assessing perceived exertion in fire fighters during simulated tasks.  相似文献   
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