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961.
Barbara Pilch-Pitera 《Journal of Polymers and the Environment》2013,21(1):215-223
Polyurethanes powder lacquers were obtained in a reaction hydroxy terminated polyester resin RUCOTE 102 and blocked polyisocyanate crosslinkers. The polyisocyanates were synthesized using alicyclic diisocyanates (IPDI and H12MDI) and monohydric aliphatic alcohols as well as dibutyltin dilaurate and triethylamine as a catalysts. The biodegradation experiments were realized in solution consisted of lipase (Novozym 735, Novozym 51,032, Lipolase 100L or Palatase 20,000) and phosphate buffer during 42 days at 37 °C. The biodegradation progress was controlled by using optical microscopy method, thermal analysis TG/DTA, DSC method, surface free energy parameters, total organic carbon measurements and sample weight loss. The three-dimensional surface topography of the powder lacquers by means of confocal microscope was investigated. The values of surface roughness parameters were calculated. 相似文献
962.
Peter Wycisk Reiner Stollberg Christian Neumann Wolfgang Gossel Holger Weiss Roland Weber 《Environmental science and pollution research international》2013,20(4):1907-1917
A large-scale groundwater contamination characterises the Pleistocene groundwater system of the former industrial and abandoned mining region Bitterfeld/Wolfen, Eastern Germany. For more than a century, local chemical production and extensive lignite mining caused a complex contaminant release from local production areas and related dump sites. Today, organic pollutants (mainly organochlorines) are present in all compartments of the environment at high concentration levels. An integrated methodology for characterising the current situation of pollution as well as the future fate development of hazardous substances is highly required to decide on further management and remediation strategies. Data analyses have been performed on regional groundwater monitoring data from about 10 years, containing approximately 3,500 samples, and up to 180 individual organic parameters from almost 250 observation wells. Run-off measurements as well as water samples were taken biweekly from local creeks during a period of 18 months. A kriging interpolation procedure was applied on groundwater analytics to generate continuous distribution patterns of the nodal contaminant samples. High-resolution geological 3-D modelling serves as a database for a regional 3-D groundwater flow model. Simulation results support the future fate assessment of contaminants. A first conceptual model of the contamination has been developed to characterise the contamination in regional surface waters and groundwater. A reliable explanation of the variant hexachlorocyclohexane (HCH) occurrence within the two local aquifer systems has been derived from the regionalised distribution patterns. Simulation results from groundwater flow modelling provide a better understanding of the future pollutant migration paths and support the overall site characterisation. The presented case study indicates that an integrated assessment of large-scale groundwater contaminations often needs more data than only from local groundwater monitoring. The developed methodology is appropriate to assess POP-contaminated mega-sites including, e.g. HCH deposits. Although HCH isomers are relevant groundwater pollutants at this site, further organochlorine pollutants are present at considerably higher levels. The study demonstrates that an effective evaluation of the current situation of contamination as well as of the related future fate development requires detailed information of the entire observed system. 相似文献
963.
Edge TA El-Shaarawi A Gannon V Jokinen C Kent R Khan IU Koning W Lapen D Miller J Neumann N Phillips R Robertson W Schreier H Scott A Shtepani I Topp E Wilkes G van Bochove E 《Journal of environmental quality》2012,41(1):21-30
Canada's National Agri-Environmental Standards Initiative sought to develop an environmental benchmark for low-level waterborne pathogen occurrence in agricultural watersheds. A field study collected 902 water samples from 27 sites in four intensive agricultural watersheds across Canada from 2005 to 2007. Four of the sites were selected as reference sites away from livestock and human fecal pollution sources in each watershed. Water samples were analyzed for Campylobacter spp., Salmonella spp., Escherichia coli O157:H7, Cryptosporidium spp., Giardia spp., and the water quality indicator E. coli. The annual mean number of pathogen species was higher at agricultural sites (1.54 ± 0.07 species per water sample) than at reference sites (0.75 ± 0.14 species per water sample). The annual mean concentration of E. coli was also higher at agricultural sites (491 ± 96 colony-forming units [cfu] 100 mL(-1)) than at reference sites (53 ± 18 cfu 100 mL(-1)). The feasibility of adopting existing E. coli water quality guideline values as an environmental benchmark was assessed, but waterborne pathogens were detected at agricultural sites in 80% of water samples with low E. coli concentrations (<100 cfu 100 mL(-1)). Instead, an approach was developed based on using the natural background occurrence of pathogens at reference sites in agricultural watersheds to derive provisional environmental benchmarks for pathogens at agricultural sites. The environmental benchmarks that were derived were found to represent E. coli values lower than geometric mean values typically found in recreational water quality guidelines. Additional research is needed to investigate environmental benchmarks for waterborne pathogens within the context of the "One World, One Health" perspective for protecting human, domestic animal, and wildlife health. 相似文献
964.
Richards RP Baker DB Crumrine JP Kramer JW Ewing DE Merryfield BJ 《Journal of environmental quality》2008,37(5):1894-1908
Sediment is an important pollutant for Lake Erie and its tributaries as a carrier of other substances and as a pollutant in its own right. Environmental managers have called for major reductions in sediment loadings in Lake Erie tributaries. In this study, 30-yr (1975-2005) datasets with daily resolution are analyzed to identify and interpret trends in sediment concentrations and loads in major US tributaries to Lake Erie. The Maumee and Sandusky Rivers in agricultural northwest Ohio show continual decreases throughout this period, but the River Raisin shows increases, especially in the last decade. The urban and forested Cuyahoga River shows little trend before 2000 but shows increases since then. The mostly forested Grand River shows strong decreases before 1995, little change thereafter until the early 2000s, and then increases. In most cases, the greatest decreases or smallest increases, depending on the river, are associated with summer and fall and with low flow conditions, whereas the smallest decreases or greatest increases are associated with the spring and with high flow conditions. Analysis of concentration-flow relationships indicates that these changes are not due to weather but reflect positive and negative anthropogenic influences. Sediment decreases in the northwestern Ohio tributaries seem to reflect the successful use of agricultural practices to reduce erosion and prevent sediment loss. Opportunities for further reductions in sediment loads and concentrations lie in better management of sediment losses during winter and spring. 相似文献
965.
966.
Evolution of a Mediterranean Coastal Zone: Human Impacts on the Marine Environment of Cape Creus 总被引:1,自引:0,他引:1
This study presents an integrated analysis of the evolution of the marine environment and the human uses in Cape Creus, a
Mediterranean coastal area where intense commercial fisheries and recreational uses have coexisted over the last fifty years.
The investigation synthesizes the documented impacts of human activities on the marine environment of Cap de Creus and integrates
them with new data. In particular, the evolution of vulnerable, exploited species is used to evaluate the fishing impacts.
The effects of area protection through the establishment of a marine reserve in the late 1990s and the potential climate change
impacts are also considered. The evolution of the human uses is marked by the increasing socioeconomic importance of recreational
activities (which affect species and habitats) in detriment to artisanal and red coral fisheries (which principally affect
at a species level). Overall, populations of sedentary, vulnerable exploited species, hard sessile benthic invertebrates,
and ecologically fragile habitats, such as seagrass meadows, the coralligenous and infralittoral algal assemblages have been
the most negatively impacted by anthropogenic activities. Albeit human uses currently constitute the largest negative impact
on the marine environment of Cap de Creus, climate change is emerging as a key factor that could have considerable implications
for the marine environment and tourism activities. The establishment of the marine reserve appears to have had little socioeconomic
impact, but there is some evidence that it had some positive biological effects on sedentary, littoral fishes. Results demonstrate
that the declaration of a marine reserve alone does not guarantee the sustainability of marine resources and habitats but
should be accompanied with an integrated coastal management plan. 相似文献
967.
Robins L 《Environmental management》2008,42(5):833-846
This paper aims to give practical meaning to ‘capacity building’ through (a) identifying a suite of practical measures, such
as mentoring or best practice guidelines, that have been shown to or are considered to build human, social, institutional,
and economic capital; (b) placing these measures within a broader systems framework; and (c) exploring stakeholder feedback
on specific measures to inform framework implementation. The 29 measures described provide actors, whether government or nongovernment,
with a suite of practical investment choices for building capacity. These measures are then clustered into eight groups according
to their primary purpose and placed within a systems framework. The framework provides a tool for actors with responsibilities
for or an interest in capacity building to inform more holistic and strategic targeting of effort and investment. Stakeholder
feedback gathered through surveys and workshops is subsequently reported to further inform implementation of specific measures
within the framework’s eight groupings. The framework presented may be built upon through the identification and inclusion
of further capacity building measures. The research is conducted within the context of decentralized governance arrangements
for natural resource management (NRM), with specific focus on Australia’s recently formalized 56 NRM regions and their community-based
governing boards as an informative arena of learning. Application of the framework is explored in the Australian setting through
the identification and comparison of measures supported and most preferred by four major stakeholder groups, namely board
members, regional NRM organization staff, policy/research interests, and Indigenous interests. The research also examines
stakeholder perceptions of capacity issues, and whether these issues are likely to be addressed through implementing their
preferred measures.
相似文献
Lisa RobinsEmail: |
968.
We documented valley and channel characteristics and wood loads in 19 reaches of forested headwater mountain streams in the
Bighorn National Forest of northern Wyoming. Ten of these reaches were in the Upper Tongue River watershed, which has a history
of management including timber harvest, tie floating, and road construction. Nine reaches were in the North Rock Creek watershed,
which has little history of management activities. We used these data to test hypotheses that (i) valley geometry correlates
with wood load, (ii) stream gradient correlates with wood load, and (iii) wood loads are significantly lower in managed watersheds
than in otherwise similar unmanaged watersheds. Statistical analyses of the data support the first and third hypotheses. Stream
reaches with steeper valley side slopes tend to have higher wood loads, and reaches in managed watersheds tend to have lower
wood loads than reaches in unmanaged watersheds. Results do not support the second hypothesis. Shear stress correlated more
strongly with wood load than did stream gradient, but statistical models with valley-scale variables had greater explanatory
power than statistical models with channel-scale variables. Wood loads in stream reaches within managed watersheds in the
Bighorn National Forest tend to be two to three times lower than wood loads in unmanaged watersheds. 相似文献
969.
Stream fish bioassessment methods assume that fish assemblages observed in sample sites reflect responses to local stressors, but fish assemblages are influenced by local factors as well as regional dispersal to and from connected streams. We hypothesized that fish movement to and from refugia and source populations in connected rivers (i.e., riverine dispersal) would weaken or decouple relations between fish community metrics and local environmental conditions. We compared fish-environment relations between streams that flow into large rivers (mainstem tributaries) and streams that lack riverine confluences (headwater tributaries) at multiple spatial grains using data from the USEPA's Environmental Monitoring and Assessment Program in the mid-Atlantic highlands, USA (n = 157 sites). Headwater and mainstem tributaries were not different in local environmental conditions, but showed important differences in fish metric responses to environmental quality gradients. Stream sites flowing into mainstem channels within 10 fluvial km showed consistently weaker relations to local environmental conditions than stream sites that lacked such mainstem connections. Moreover, these patterns diminished at longer distances from riverine confluences, consistent with the hypothesis of riverine dispersal. Our results suggest that (1) the precision of fish bioassessment metrics may be improved by calibrating scoring criteria based on the spatial position of sites within stream networks and (2) the spatial grain of fish bioassessment studies may be manipulated to suit objectives by including or excluding fishes exhibiting riverine dispersal. 相似文献
970.
Detecting Temporal Change in Watershed Nutrient Yields 总被引:2,自引:1,他引:1
Meta-analyses reveal that nutrient yields tend to be higher for watersheds dominated by anthropogenic uses (e.g., urban, agriculture) and lower for watersheds dominated by natural vegetation. One implication of this pattern is that loss of natural vegetation will produce increases in watershed nutrient yields. Yet, the same meta-analyses also reveal that, absent land-cover change, watershed nutrient yields vary from one year to the next due to many exogenous factors. The interacting effects of land cover and exogenous factors suggest nutrient yields should be treated as distributions, and the effect of land-cover change should be examined by looking for significant changes in the distributions. We compiled nutrient yield distributions from published data. The published data included watersheds with homogeneous land cover that typically reported two or more years of annual nutrient yields for the same watershed. These data were used to construct statistical models, and the models were used to estimate changes in the nutrient yield distributions as a result of land-cover change. Land-cover changes were derived from the National Land Cover Database (NLCD). Total nitrogen (TN) yield distributions increased significantly for 35 of 1550 watersheds and decreased significantly for 51. Total phosphorus (TP) yield distributions increased significantly for 142 watersheds and decreased significantly for 17. The amount of land-cover change required to produce significant shifts in nutrient yield distributions was not constant. Small land-cover changes led to significant shifts in nutrient yield distributions when watersheds were dominated by natural vegetation, whereas much larger land-cover changes were needed to produce significant shifts when watersheds were dominated by urban or agriculture. We discuss our results in the context of the Clean Water Act. 相似文献