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An assessment of the risks associated with PCDDs and PCDFs following the application of sewage sludge to agricultural land in the UK 总被引:4,自引:0,他引:4
A model has been developed to describe the transfer of PCDDs and PCDFs from sludge-amended soils to the human foodchain. The model is conservative and assumes that all foods consumed by an individual are derived from sludge-amended soils. Predicted concentrations of PCDDs and PCDFs in potatoes, cereals, root vegetables and leafy vegetables were in close agreement with mean concentrations reported in the food survey conducted by MAFF in the UK. Predicted concentrations in milk were well below the Maximum Tolerable Concentration adopted by MAFF. Assuming a half-life of ten years in sludge-amended soils, the maximum estimated incremental daily intake (IDI) predicted by the model following ten applications of sludge to agricultural land was 0.80 pg I-TEQ kg−1 day−1, representing an increase of approximately 45% on current levels of background exposure. For an individual whose diet is solely derived from sludge-amended soils, the total exposure is predicted to be approximately 181 pg I-TEQ day−1 or 2.6 pg I-TEQ kg−1 day−1. This compares with an average background exposure of approximately 2 pg I-TEQ kg−1 day−1, well within the TDI of 10 pg I-TEQ kg−1 day−1 and indicates that the application of sewage sludge to agricultural land under the conditions assumed would not appear to present a significant health risk under the conservative scenarios considered in this assessment. 相似文献
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Median barriers separate lanes of traffic moving in opposite directions on multilane highways. Such traffic safety devices can reduce head-on collisions but also have the potential to reduce landscape permeability by impeding wildlife movements across highways. Median barriers may also increase the risk of wildlife–vehicle collisions if an animal becomes trapped or confused amid barriers searching for a place to cross. A 2002 Transportation Research Board report highlighted the need to better understand the potential impacts of highway median barriers on wildlife. This lack of information can cause significant project delays and increase transportation project costs. This study represents the first attempt in North America to bring together information about highway median and roadside barriers and wildlife and provide preliminary guidelines to balance the needs of motorist safety and wildlife movements. 相似文献
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Current United States National Park Service (NPS) management is challenged to balance visitor use with the environmental and
social consequences of automobile use. Wildlife populations in national parks are increasingly vulnerable to road impacts.
Other than isolated reports on the incidence of road-related mortality, there is little knowledge of how roads might affect
wildlife populations throughout the national park system. Researchers at the Western Transportation Institute synthesized
information obtained from a system-wide survey of resource managers to assess the magnitude of their concerns on the impacts
of roads on park wildlife. The results characterize current conditions and help identify wildlife-transportation conflicts.
A total of 196 national park management units (NPS units) were contacted and 106 responded to our questionnaire. Park resource
managers responded that over half of the NPS units’ existing transportation systems were at or above capacity, with traffic
volumes currently high or very high in one quarter of them and traffic expected to increase in the majority of units. Data
is not generally collected systematically on road-related mortality to wildlife, yet nearly half of the respondents believed
road-caused mortality significantly affected wildlife populations. Over one-half believed habitat fragmentation was affecting
wildlife populations. Despite these expressed concerns, only 36% of the NPS units used some form of mitigation method to reduce
road impacts on wildlife. Nearly half of the respondents expect that these impacts would only worsen in the next five years.
Our results underscore the importance for a more systematic approach to address wildlife-roadway conflicts for a situation
that is expected to increase in the next five to ten years. 相似文献
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Bin Hua Kristen Veum Amod Koirala John Jones Thomas Clevenger Baolin Deng 《Environmental Chemistry Letters》2007,5(2):73-77
Water samples from 56 lakes of Missouri, USA, were analysed for their fluorescence excitation/emission matrix (EEM) spectroscopy
and the formation potentials of total trihalomethanes (TTHM) and N-nitrosodimethylamine (NDMA). Comparing the excitation/emission matrix fingerprints with trihalomethanes formation revealed
that water with higher fluorescence intensity generally exhibited higher trihalomethanes formation potential. Moreover, waters
with fluorescence centre at excitation: 290–310 nm/emission: 330–350 nm were related to high N-nitrosodimethylamine and trihalomethanes formation potentials. The results suggest that excitation/emission matrix fingerprints
could be used as surrogate parameters for monitoring trihalomethanes and N-nitrosodimethylamine formation potentials. 相似文献
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Kari E. Gunson Anthony P. Clevenger Adam T. Ford John A. Bissonette Amanda Hardy 《Environmental management》2009,44(2):268-277
Wildlife-vehicle collisions (WVCs) pose a significant safety and conservation concern in areas where high-traffic roads are
situated adjacent to wildlife habitat. Improving transportation safety, accurately planning highway mitigation, and identifying
key habitat linkage areas may all depend on the quality of WVC data collection. Two common approaches to describe the location
of WVCs are spatially accurate data derived from global positioning systems (GPS) or vehicle odometer measurements and less
accurate road-marker data derived from reference points (e.g., mile-markers or landmarks) along the roadside. In addition,
there are two common variable types used to predict WVC locations: (1) field-derived, site-specific measurements and (2) geographic
information system (GIS)-derived information. It is unclear whether these different approaches produce similar results when
attempting to identify and explain the location of WVCs. Our first objective was to determine and compare the spatial error
found in road-marker data (in our case the closest mile-marker) and landmark-referenced data. Our second objective was to
evaluate the performance of models explaining high- and low-probability WVC locations, using congruent, spatially accurate
(<3-m) and road-marker (<800-m) response variables in combination with field- and GIS-derived explanatory variables. Our WVC
data sets were comprised of ungulate collisions and were located along five major roads in the central Canadian Rocky Mountains.
We found that spatial error (mean ± SD) was higher for WVC data referenced to nearby landmarks (516 ± 808 m) than for data
referenced to the closest mile-marker data (401 ± 219 m). The top-performing model using the spatially accurate WVC locations
contained all explanatory variable types, whereas GIS-derived variables were only influential in the best road-marker model
and the spatially accurate reduced model. Our study showed that spatial error and sample size, using road-marker data for
ungulate species, are important to consider for model output interpretation, which will impact the appropriate scale on which
to apply modeling results. Using road-marker references <1.6 km or GPS-derived data locations may represent an optimal compromise
between data acquisition costs and analytical performance.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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