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471.
Survey of arsenic and its speciation in rice products such as breakfast cereals, rice crackers and Japanese rice condiments 总被引:1,自引:0,他引:1
Sun GX Williams PN Zhu YG Deacon C Carey AM Raab A Feldmann J Meharg AA 《Environment international》2009,35(3):473-475
Rice has been demonstrated to be one of the major contributors to arsenic (As) in human diets in addition to drinking water, but little is known about rice products as an additional source of As exposure. Rice products were analyzed for total As and a subset of samples were measured for arsenic speciation using high performance liquid chromatography interfaced with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). A wide range of rice products had total and inorganic arsenic levels that typified those found in rice grain including, crisped rice, puffed rice, rice crackers, rice noodles and a range of Japanese rice condiments as well as rice products targeted at the macrobiotic, vegan, lactose intolerant and gluten intolerance food market. Most As in rice products are inorganic As (75.2-90.1%). This study provides a wider appreciation of how inorganic arsenic derived from rice products enters the human diet. 相似文献
472.
Andrea Critto Paola Agostini 《Environmental science and pollution research international》2009,16(6):649-662
Background, aim, and scope
The management of contaminated sites requires the investigation of different involved aspects (from socioeconomic to risk and technological issues) and the presentation of useful and condensed information to decision makers. For this purpose, indices are more and more recognized as effective and valuable tools. This paper presents specific indices created within the DEcision Support sYstem for REhabilitation of contaminated sites (DESYRE). 相似文献473.
Jeffrey D. Connor Darla Hatton MacDonald Mark Morrison Andrea Cast 《The Environmentalist》2009,29(4):348-359
Environmental policy makers are interested in ways to prevent environmental degradation without significantly limiting economic
and social development. Increasingly, market-based instruments are being incorporated into the suite of policy tools to accomplish
these aims. However, the lack of information on market-based instruments accessible to non-economists limits understanding
of how and when a market-based instrument can be integrated into a traditional policy regime. This paper aims to address the
lack of accessible information using a generic screening process for policy instruments demonstrated through application to
a non-point source pollution problem in Lake Taupo, New Zealand. 相似文献
474.
PCDD/Fs in ambient air in north-east Italy: The role of a MSWI inside an industrial area 总被引:1,自引:0,他引:1
Andrea Colombo Emilio Benfenati Giulio Mariani Marco Lodi Roberto Marras Giuseppe Rotella Vincenzo Senese Elena Fattore Roberto Fanelli 《Chemosphere》2009,77(9):1224-1229
The stack gases of a municipal solid waste incinerator (MSWI), and ambient air were sampled in four locations around the plant for the analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs). The sampling area was close to an industrial area near Trieste, in north-east Italy. The purpose of the study was to estimate the impact of the MSWI emissions and to distinguish the contribution of these emissions from other potential emission sources in the industrial area.PCDD/F atmospheric concentrations were similar to those generally detected in urban–rural areas with one location about 2–3 times more contaminated than the others. Since the most contaminated location was inside the industrial area but upwind of the MSWI, principal component analysis (PCA) was used to establish whether other sources were the cause. This analysis clearly showed that a local steel plant’s emission was the main source of PCDDs/Fs in ambient air. This study highlights the usefulness of multivariate data analysis such as PCA to identify, among different potential emission sources, the one really responsible for the contamination. 相似文献
475.
The role of optimality in characterizing CO2 seepage from geologic carbon sequestration sites 总被引:1,自引:0,他引:1
Andrea Cortis Curtis M. Oldenburg Sally M. Benson 《International Journal of Greenhouse Gas Control》2008,2(4):640
Storage of large amounts of carbon dioxide (CO2) in deep geologic formations for greenhouse-gas mitigation is gaining momentum and moving from its conceptual and testing stages towards widespread application. In this work we explore various optimization strategies for characterizing surface leakage (seepage) using near-surface measurement approaches such as accumulation chambers and eddy covariance towers. Seepage characterization objectives and limitations need to be defined carefully from the outset especially in light of large natural background variations that can mask seepage. The cost and sensitivity of seepage detection are related to four critical length scales pertaining to the size of the: (1) region that needs to be monitored; (2) footprint of the measurement approach, and (3) main seepage zone; (4) region in which concentrations or fluxes are influenced by seepage. Seepage characterization objectives may include one or all of the tasks of detecting, locating, and quantifying seepage. Each of these tasks has its own optimal strategy. Detecting and locating seepage in a region in which there is no expected or preferred location for seepage nor existing evidence for seepage requires monitoring on a fixed grid, e.g., using eddy covariance towers. The fixed-grid approaches needed to detect seepage are expected to require large numbers of eddy covariance towers for large-scale geologic CO2 storage. Once seepage has been detected and roughly located, seepage zones and features can be optimally pinpointed through a dynamic search strategy, e.g., employing accumulation chambers and/or soil-gas monitoring. Quantification of seepage rates can be done through measurements on a localized fixed grid once the seepage is pinpointed. Background measurements are essential for seepage detection in natural ecosystems. Artificial neural networks are considered as regression models useful for distinguishing natural system behavior from anomalous behavior suggestive of CO2 seepage without need for detailed understanding of natural system processes. Because of the local extrema in CO2 fluxes and concentrations in natural systems, simple steepest-descent algorithms are not effective and evolutionary computation algorithms are proposed as a paradigm for dynamic monitoring networks to pinpoint CO2 seepage areas. 相似文献
476.
Residues of malachite green (MG), a veterinary drug illegally used for the treatment of aquacultured fish, have been found in wild eels caught from surface waters downstream from the sewers of different municipal sewage treatment plants (STPs). MG and its metabolite leucomalachite green (LMG) were detected with total concentrations up to 0.765 microg kg(-1) fresh weight in the tissues of 25 out of 45 eels caught from different lakes, a river and a canal in Berlin, Germany. In all cases, the occurrence of the residues could directly be linked to the presence of discharges by municipal STPs into the receiving surface waters. MG is a multiple-use compound that is also used to color materials. Thus, it appears to be reasonable that the residues of MG found in the eel samples originate from such uses, e.g. by wash off from clothes or paper towels colored with MG. Additional loads from legal uses of MG as veterinary drug for the treatment of ornamental fish (private aquaria) are possible. The results obtained from this study are the first proof of background contaminations of a veterinary drug found in samples of fish not intentionally treated with such agents. MG and LMG are regarded as potential genotoxic carcinogens making it impossible to establish a tolerable daily intake. A margin of exposure (MOE) approach was applied to evaluate the human health risk associated with the consumption of the eels investigated in this study. With a MOE of 3.4 million the chronic risk was classified as being very low. Nevertheless, due to their potential to act as genotoxic carcinogens, any oral exposure to residues of MG and LMG should be avoided. According to European Union law, zero tolerance applies to all residues of MG and LMG found in food for human consumption as MG is not registered for use as veterinary drug. 相似文献
477.
Contamination by polybrominated diphenyl ethers of sediments from the Lake Maggiore basin (Italy and Switzerland) 总被引:1,自引:0,他引:1
Polybrominated diphenyl ethers (PBDEs) are characterized by chemical properties and toxicological profiles similar to other POPs (persistent organic pollutants) included in the EU Priority Pollutant List (2455/01/CE). However, limited data have been available for these compounds thus far for Italian freshwater abiotic matrices. Lake Maggiore basin, a heavily industrialized and densely populated area, was selected for studying PBDE contamination in Italy. PBDEs and OCs (organochlorine compounds) in the basin were quantified by analysing both sediment cores collected in 2005 from the lake and grab samples from the main tributaries and the emissary. Fourteen PBDEs, from tri-BDE to hepta-BDE congeners and BDE209, were compared with some organochlorine POPs (PCBs and DDTs) characterizing Lake Maggiore basin contamination. Analyses of tri-to hepta-BDEs, PCBs and DDTs were undertaken by GC-MS/MS, while BDE-209 was analysed by GC/ECD. Results showed a dominant presence of BDE-209 (>95% of SigmaBDE) and limited amounts of BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154. Lake core profiles highlighted a decreasing trend in PCB concentrations starting from the year 2000, while PBDEs showed greater concentrations after the beginning of the 1990s (up to 30 ng g(-1)d.w.). Among the tributaries, the Bardello and Boesio rivers were the most PBDE-contaminated (up to 290 ng g(-1)d.w.). 相似文献
478.
Nitrogen deposition is a continuing problem in European alpine regions. We hypothesised that, despite climatic limitations, low-alpine Calluna heathland would respond to nitrogen addition with increased shoot growth and flowering and that fire and grazing would modify responses. In a five-year study, 0-50kgNha(-1)y(-1) were added, combined with burning (+/-) and clipping (+/-). Calluna vulgaris responded with increased shoot extension, but effects on flowering were variable. Burning enhanced the positive effect of nitrogen addition and negative effects of clipping. Sub-dominant shrubs generally did not respond to nitrogen. C. vulgaris shoot extension was stimulated by nitrogen addition of 10kgNha(-1)y(-1) (above background) supporting suggestions that alpine heathlands are sensitive to low levels of nitrogen deposition. Increased C. vulgaris growth could negatively impact on important lichen components of this vegetation through increased shading and competition. Climatic factors constrain productivity in this community, but do not prevent rapid responses to nitrogen deposition by some species. 相似文献
479.
Sperm exchange in a simultaneous hermaphrodite 总被引:3,自引:0,他引:3
Many simultaneously hermaphroditic animals cross-inseminate when copulating, even though unilateral sperm exchange is functionally
possible. The question is why reciprocity is the rule. This study addresses sperm exchange in a hermaphroditic planarian flatworm,
Dugesia polychroa, in which self-fertilisation does not occur. We investigated the availability of self sperm for inseminating a partner, how
self sperm affects the likelihood of sperm donation, and whether sperm donation depends on reciprocation by the partner. The
amount of self sperm depended on body size, duration of isolation and experimental date, and animals that had more self sperm
were more likely to mate. Depletion of allosperm (sperm received from partners) played only an indirect role, suggesting that
animals copulate more to donate sperm rather than to replenish allosperm reserves. Among 60 copulating pairs, reciprocal insemination
was more common (63.3%) than unilateral transfer (18.3%). A surprising 18.3% did not exchange sperm in either direction. Individuals
were more likely to behave like their partners, resulting in more symmetrical matings (either reciprocity or no sperm exchange)
than asymmetrical matings (unilateral sperm donation). The amount of self sperm donated during a copulation depended mainly
on the amount available before the copulation and not on the amount received from the partner. The results suggest that conditional
sperm exchange, or sperm trading, takes place in D. polychroa.
Received: 31 May 1997 / Accepted after revision: 1 December 1997 相似文献
480.
The immense value of a geographic information system for flood control has been experienced by the decision-markers of the
Dutch province of Gelderland during the flood of the Rivers Meuse (Maas) and Waal in January 1995. Super-imposing different
‘data layers’, GIS-experts could detect the weak parts in the dikes and generate and evacuation plan. Shortcomings within
the organization were experienced as well: important data could not be retrieved, and the coordination of efforts by the different
governmental departments and institutions was not optimal. To overcome these shortcomings and to optimize the modelling process,
a spatial decision support system (SDSS) is being proposed, aggregating several models, heuristic and procedural, into integrated
software tools. As becomes clear from two cases of flood control described, ‘emergency managers’ should be able to communicate
about spatial data available and have access to selected spatial data. In order to improve communication between data sources,
data processing and the use of relevant spatial data in GISs, a new ‘Spatial Information Infrastructure’ (SII) needs to be
developed. This requires both technical and organizational solutions and standards. Proper documentation of the data will
allow the GIS-experts to more quickly find, store, update and reuse the data. A range of ‘metadata’ services exist documenting
data sets, typically limited by thematic or national boundaries. There are no standards in common practice for structuring
and classifying spatial information. The user of spatial information cannot easily browse across Web-sites and compare products
from different suppliers. Even, if the search has been successful, the user all too often has to face a complex process of
negotiation, and highly technical data integration issues. A consortium of European GIS-experts has addressed these problems
and launched the ‘European Spatial Metadata Infrastructure’ (ESMI) project with the objective to link existing and future
metadata systems using Internet. 相似文献