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121.
Development and evaluation of a Macroinvertebrate Biotic Integrity Index (MBII) for regionally assessing Mid-Atlantic Highlands Streams 总被引:5,自引:0,他引:5
Klemm DJ Blocksom KA Fulk FA Herlihy AT Hughes RM Kaufmann PR Peck DV Stoddard JL Thoeny WT Griffith MB Davis WS 《Environmental management》2003,31(5):0656-0669
The Macroinvertebrate Biotic Integrity Index (MBII) was developed from data collected at 574 wadeable stream reaches in the
Mid-Atlantic Highlands region (MAHR) by the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment
Program (EMAP). Over 100 candidate metrics were evaluated for range, precision, responsiveness to various disturbances, relationship
to catchment area, and redundancy. Seven metrics were selected, representing taxa richness (Ephemeroptera richness, Plecoptera
richness, Trichoptera richness), assemblage composition (percent non-insect individuals, percent 5 dominant taxa), pollution
tolerance [Macroinvertebrate Tolerance Index (MTI)], and one functional feeding group (collector-filterer richness). We scored
metrics and summed them, then ranked the resulting index through use of independently evaluated reference stream reaches.
Although sites were classified into lowland and upland ecoregional groups, we did not need to develop separate scoring criteria
for each ecoregional group. We were able to use the same metrics for pool and riffle composite samples, but we had to score
them differently. Using the EMAP probability design, we inferred the results, with known confidence bounds, to the 167,797
kilometers of wadeable streams in the Mid-Atlantic Highlands. We classified 17% of the target stream length in the MAHR as
good, 57% as fair, and 26% as poor. Pool-dominated reaches were relatively rare in the MAHR, and the usefulness of the MBII
was more difficult to assess in these reaches. The process used for developing the MBII is widely applicable and resulted
in an index effective in evaluating region-wide conditions and distinguishing good and impaired reaches among both upland
and lowland streams dominated by riffle habitat. 相似文献
122.
Previous research has established clear relationshipsbetween the chemical composition of surface waters andthe nature of their contributing catchments. Theserelationships are particularly strong when broadenvironmental gradients are considered. However, forfreshwaters at higher altitudes, some of the catchmentprocesses that mediate chemical composition are lessinfluential than those at lower altitudes. The waterchemistry of 85 upland lochs in Scotland, U.K. is examinedto assess differences in chemical composition along arelatively short altitude gradient. Principal componentsanalysis identifies the main gradients of variationwithin the dataset. A series of digital datasets is usedto characterise the catchments according to a range ofattributes including soils and landcover. Multivariatestatistical analysis is undertaken to examine the extentto which the catchment attributes can explain variationin surface water chemistry in upland systems. Theseempirical relationships may be used in the development ofregionalisation procedures, which will allow upscaling ofknowledge from individual sites to regions. 相似文献
123.
A regional framework for establishing recovery criteria 总被引:6,自引:0,他引:6
Robert M. Hughes Thomas R. Whittier Christina M. Rohm David P. Larsen 《Environmental management》1990,14(5):673-683
Effective assessments of aquatic ecosystem recovery require ecologically sound endpoints against which progress can be measured.
Site-by-site assessments of end points and potential recovery trajectories are impractical for water resource agencies. Because
of the natural variation among ecosystems, applying a single set of criteria nationwide is not appropriate either. This article
demonstrates the use of a regional framework for stratifying natural variation and for determining realistic biological criteria.
A map of ecoregions, drawn from landscape characteristics, formed the framework for three statewide case studies and three
separate studies at the river basin scale. Statewide studies of Arkansas, Ohio, and Oregon, USA, streams demonstrated patterns
in fish assemblages corresponding to ecoregions. The river basin study in Oregon revealed a distinct change at the ecoregion
boundary; those in Ohio and Montana demonstrated the value of regional reference sites for assessing recovery. Ecoregions
can be used to facilitate the application of ecological theory and to set recovery criteria for various regions of states
or of the country. Such a framework provides an important alternative between site-specific and national approaches for assessing
recovery rates and conditions. 相似文献
124.
This study describes the distribution of sewage pollution markers (faecal coliforms, Clostridium perfringens and faecal sterols) in seawater and marine sediments around Rothera Research Station, Antarctic Peninsula. Untreated sewage waste has been released from this site since 1975, creating the potential for long-term contamination of the benthic environment. Faecal coliform concentrations in seawater reached background levels within 300 m of the outfall. In sediment cores, both C. perfringens and faecal coliform concentrations declined with distance from the outfall, though C. perfringens persisted at greater depths in the sediment. High concentrations of 5beta(H)-cholestan-3beta-ol (coprostanol) relative to the corresponding 5alpha-epimer (cholestanol), indicative of sewage pollution, were only found in sediments within 200 m of the sewage outfall. This study has shown that sewage contamination is limited to the immediate vicinity of the sewage outfall. Nevertheless, a sewage treatment plant was installed in February 2003 to reduce this contamination further. 相似文献
125.
Particulate matter (PM) has been associated with adverse respiratory outcomes in numerous studies that utilized data from emergency room visits, hospital admissions, and mortality records. This study is unique in its investigation of associations of air pollution measures, including components of PM, with health outcomes in an ambulatory-care setting. Visit data were collected from Kaiser Permanente, a not-for-profit health maintenance organization in the metropolitan Atlanta, GA, area. Kaiser Permanente collaborated on the Aerosol Research Inhalation Epidemiological Study (ARIES), which provided detailed information on the characteristics of air pollutants. The Kaiser Permanente study was a time-series investigation of the possible associations between daily levels of suspended PM, inorganic gases, and polar volatile organic compounds and ambulatory care acute visit rates during the 25-month period from August 1, 1998, to August 31, 2000. For this interim analysis, the a priori 0-2 days lagged moving average, as well as the 3-5 days and 6-8 days lagged moving averages, of air quality measures were investigated. Single-pollutant Poisson general linear modeling was used to model daily visit counts for asthma and upper and lower respiratory infections (URI and LRI) by selected air quality metrics, controlling for temporal trends and meteorological variables. Most of the statistically significant positive associations were for the 3-5 days lagged air quality metrics with child asthma and LRI. 相似文献
126.
Jennifer Harlow Denise Oudit Ashton Hughes Kirsten Mattison 《Food and environmental virology》2011,3(1):31-34
Shellfish are an important cause of foodborne viral illness. Consumer-friendly cooking recommendations for shellfish could
improve food safety and decrease the risk for infection from contaminated products. Thermal inactivation parameters were established
for hepatitis A virus (HAV) in mussels and validated with cooking experiments. Steaming for only 2–5 min was not sufficient
to inactivate HAV in mussels in all layers of a steamer. Steaming mussels for 6 min was sufficient to inactivate HAV in all
layers. These cooking guidelines produce shellfish with a reduced risk for foodborne virus transmission. 相似文献
127.
We investigated the e ects of environmental factors and properties of water-stable crystal fullerene (nC60) on the uptake of nC60
by Daphnia magna based on known accumulation in our laboratory. This study was performed for seven days using di erent
environmental factors including temperature, pH, water hardness, concentration (density of particle), and particle size. Results
demonstrated that body burden of C60 increased with time in all experiments. Body burden of C60 increased with increasing
concentration and particle size, and uptake of particles >100 nm reached their maximums more quickly than those <100 nm. Under
high hardness in aqueous systems with lower pH and high temperature, uptake was higher than those under opposite conditions. Uptake
in all batch tests reached balance within five days. Both nC60 properties and environmental factors influenced uptake of nC60 by D.
magna in an aqueous system. Additionally, environmental factors may have a ected accumulation by changing nC60 properties, which
are critical to understand the accumulation of fullerenes in aqueous systems. 相似文献
128.
129.
Ge Sun Devendra M. Amatya Steven G. McNulty R. Wayne Skaggs Joseph H. Hughes 《Journal of the American Water Resources Association》2000,36(2):367-374
ABSTRACT: There are increasing concerns in the forestry community about global climate change and variability associated with elevated atmospheric CO2. Changes in precipitation and increases in air temperature could impose additional stress on forests during the next century. For a study site in Carteret County, North Carolina, the General Circulation Model, HADCM2, predicts that by the year 2099, maximum air temperature will increase 1.6 to 1.9°C, minimum temperature will increase 2.5 to 2.8°C, and precipitation will increase 0 to 10 percent compared to the mid‐1990s. These changes vary from season to season. We utilized a forest ecosystem process model, PnET‐II, for studying the potential effects of climate change on drainage outflow, evapotranspiration, leaf area index (LAI) and forest Net Primary Productivity (NPP). This model was first validated with long term drainage and LAI data collected at a 25‐ha mature loblolly pine (Pinus taeda L.) experimental watershed located in the North Carolina lower coastal plain. The site is flat with poorly drained soils and high groundwater table. Therefore, a high field capacity of 20 cm was used in the simulation to account for the topographic effects. This modeling study suggested that future climate change would cause a significant increase of drainage (6 percent) and forest productivity (2.5 percent). Future studies should consider the biological feedback (i.e., stomata conductance and water use efficiency) to air temperature change. 相似文献
130.
Yiliang He Bin Zhao Joseph B. Hughes Sung Soo Han 《Frontiers of Environmental Science & Engineering》2008,2(3):326-332
The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4- and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4- and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography (HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde → 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol. 相似文献