Vehicular traffic is one of the main sources of antimony in highly populated urban areas like Buenos Aires where an overall traffic density of 1 500 000 vehicles per day (corresponding to 7500 vehicles km(-2)) is estimated. In this context, a study was undertaken to ascertain the levels of Sb and other traffic-related elements (TRE) in the atmosphere of this city. To this end, sixty-seven samples of PM-10 particulate matter were collected during eight days in nine representative sampling sites located downtown Buenos Aires and spread over an area of about 30 km2. The collection of particulate matter was performed on ash-free glass-fibre filters using high volume samplers with PM-10 sampling heads. A combination of aqua regia and perchloric acid was used for leaching metals from filters. The resulting solutions were evaporated and then diluted with 0.1 mol l(-1) HCl. Antimony was determined by inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) at ng g(-1) levels. Concentrations of Sb varied from 12.9 +/- 0.9 to 375 +/- 23 microg g(-1)(equivalent to 0.87 +/- 0.06 to 15.3 +/- 0.8 ng m(-3)). Statistical analysis was performed on the data set including the measured PM-10 mass and Sb concentrations for the monitored period. Correlations of Sb with other TRE namely, Cu and Mo were also assessed. The highest concentrations of Sb were detected at two sites (Hospital Alemán and Casa Rapallini) located in streets with traffic consisting mostly of passenger cars and showing a "stop-and-go" pattern in peak hours. Antimony levels in the Buenos Aires PM-10 are by far below the level of 0.5 mg m(-3)(for an 8 hour workday, 40 hour work week) set by the US Occupational Safety and Health Administration (OSHA) for occupational exposure. However, monitoring of Sb and other TRE should be carried out in a systematic fashion to detect the possibility of increases in from the present levels. 相似文献
The pulp and paper industry generates large volume of wastewater that adversely affects water resources. Lignin derived macromolecular compounds, similar to natural humic substances, are the main waste products in the pulp mill effluents. The UV-Vis and fluorescence spectroscopies were used to assess the effect of solar exposition on fulvic acids from a kraft pulp mill effluent. Solar irradiation of the solutions of these fulvic acids caused solution acidification and decay both in the UV-Vis absorbance and in the fluorescence. This decay was not the same for the whole spectra but pointed to the selective photodegradation of lignin typical structures. Furthermore, by sequential ultrafiltration it was found that during irradiation, the high-molecular weight fractions were destroyed and low-molecular-weight constituents, potentially more able to penetrate the cell membranes of living organisms were formed. Photodegradation of macromolecular organic matter from a kraft pulp mill effluent may be a key process occurring in natural waters that modifies the physicochemical properties of such effluents. 相似文献
Based on production data published by the Brazilian Mineral Water Producers Association, bottled mineral waters were bought at the market, covering, at least, 50% of the annual production of each Brazilian geographical region. 228Ra, 226Ra and 210Pb were analyzed and the weighted mean values obtained for Brazilian mineral waters were 0.097, 0.027 and 0.066 Bq l-1 respectively. Individual effective dose rate estimates due to ingestion of mineral water in Brazil were of the order of 10-100 microSv yr-1, depending on the geographical region. Based on the available data, it was also possible to evaluate the per caput effective dose rate and the highest value obtained was 4.3 microSv yr-1 for the northern region. 相似文献
Urban and industrial development has caused a major impact on environmental soil quality. This work assesses the extent and
severity of contamination in a small urban area subjected to an industrial impact and identifies the major anthropogenic inputs.
Twenty-six soil samples were collected from agricultural and urban sites, and concentrations of potentially toxic elements
(As, Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn), PAHs and PCBs, were determined. In spite of the low median concentrations observed,
some sites represent a potential hazard for human health and ecosystems. Concentrations of contaminants were higher than those
found in a nearby city, indicating that the study area is affected by the surrounding industry. The use of multivariate statistical
analyses allowed for the identification of the main factors controlling the variability of potentially toxic elements and
organic pollutants in the soils. The presence of Cr, Fe, Mn and Ni was associated with geogenic inputs, and Cu, Pb, Zn, As,
PAHs and PCBs were associated with anthropogenic inputs. Industry and traffic were the most important anthropogenic sources.
Soil characteristics were identified as important factors controlling the spatial variability of elements, both from recognised
natural and anthropogenic origin. Differences between land uses were observed, which may be attributed to both management
practices and proximity to sources. 相似文献
Understanding the transfer of mercury (Hg) from soil to crops is crucial due to Hg toxicity and Hg occurrence in terrestrial
systems. Previous research has shown that available Hg in soils contributes to plant Hg levels. Plant Hg concentrations are
related to soil conditions and plant characteristics. Mechanistic models describing such soil–plant interactions are however
difficult to quantify. Here we performed a field study in agricultural, mining and industrial areas in Portugal to evaluate
potential food chain risks. The uptake of Hg by Italian ryegrass, ryegrass, orchard grass, collard greens and rye was measured
to calculate daily intakes (DI) of Hg for cows and sheep grazing. A total of 136 soil samples and 129 plant samples were analysed.
Results show that total Hg concentrations ranged from 0.01 to 98 mg kg−1 in soils; 0.01–5.4 mg kg−1 in shoots and 0.01–42 mg kg−1 in roots. Calculated DI ranged from 0.18 to 132 mg d−1 for cows, and from 0.028 to 23 mg d−1 for sheep. In 27 grassland sites, daily intakes exceeded the acceptable daily intake of both cows and sheep in view of food
safety considering Hg in animal kidneys evidencing potential risks to human health. The transfer of Hg from soil to crops
was described using empirical Freundlich-type functions. For ryegrass, orchard grass and collard greens, the soil-to-root
or soil-to-shoot transfer of Hg appeared to be controlled by the total soil Hg concentration and levels of Alox and Feox. Empirical functions allowed us to obtain realistic estimates of Hg levels in crops and can be used as an alternative to
mechanistic models when evaluating food chain risks of Hg contamination in agricultural soils. 相似文献
Several mutagenic agents may be present in substances released in the environment, which may cause serious environmental impacts. Among these substances, there is a special concern regarding the widespread use of silver nanoparticles (AgNP) in several products due to their widely known bactericidal properties, including in the medical field and the food industry (e.g., active packaging). The assessment of the effects of AgNP released in the environment, having different concentrations, sizes, and being associated or not to other types of materials, including polymers, is therefore essential. In this research, the objective was to evaluate the genotoxic and cytotoxic effects of AgNP (size range between 2 and 8 nm) on root meristematic cells of Allium cepa (A. cepa). Tests were carried out in the presence of colloidal solution of AgNP and AgNP mixed with carboxymethylcellulose (CMC), using distinct concentrations of AgNP. As a result, when compared to control samples, AgNP induced a mitotic index decrease and an increase of chromosomal aberration number for two studied concentrations. When AgNP was in the presence of CMC, no cytotoxic potential was verified, but only the genotoxic potential for AgNP dispersion having concentration of 12.4 ppm. 相似文献
This study assessed the concentration, bioconcentration, and bioaccumulation of As, Cd, Co, Cr, Cu, Mg, Mn, Ni, Pb, and Zn in juvenile fishes (Acestrorynchus pantaneiro, Brycon orbygnianus, Cyphocharax voga, Megaleporinus obtusidens, Odontesthes bonariensis, Pimelodus maculatus, Prochilodus lineatus, Salminus brasiliensis, and Schizodon borelli) in the Lower Paraná River (Argentina), the most extensive floodplain from the Plata Basin. The floodplain is crucial for the reproduction and growth of various species such as P. lineatus, M. obtusidens, and S. brasiliensis, which complete their life cycle in this environment. In total, 90 individuals were sampled for nitrogen stable isotope, and trace element analysis in muscle tissue, water, and sediment was analyzed. The results show that all the studied species bioaccumulate Cr, Mg, Ni, and Zn. In particular, B. orbygnianus and P. maculatus presented the highest bioaccumulation factor for Cr. A biodilution of Co through the food chain was observed. No positive correlation was found between element concentration and trophic level, but we observed significant differences between trophic guilds (herbivorous, omnivorous, and carnivorous). Our findings suggest that feeding habits determine trace element concentrations. To establish differential behavior between different species within the aquatic web further studies are necessary, particularly in the floodplain of the Paraná, which is a crucial nursery area for most commercially important fishes from the Plata Basin.