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241.
Sulfate () concentrations and fluxes were studied for multiple storm events in the Point Peter Brook watershed, a glaciated, forested
watershed located in Western New York, USA. Investigations were performed across one large (696 ha) and three small (1.6–3.4 ha)
catchments with varying extent of riparian and wetland areas. Concentrations of in groundwater sources (mean values: 238–910 μmolc L−1) were considerably greater than concentrations recorded for rainfall (60 μmolc L−1) and throughfall (72–129 μmolc L−1). Seasonality in concentrations was most pronounced for valley-bottom riparian waters with maximum concentrations in late winter–spring (February–March)
and a minimum in late summer (August). Concentrations of in wetland water were considerably less than riparian water indicating the likelihood of reduction in anoxic wetland conditions. Storm events displayed a dilution pattern in concentrations with a minimum coinciding with the maximum in throughfall contributions. End member mixing analysis (EMMA)
was able to predict the storm event concentrations of for four of the six comparisons. Concentrations of at the outlet of the large (696 ha) catchment were much greater than values recorded for the smaller catchments. Exports
of in streamflow exceeded the inputs from atmospheric deposition suggesting that watersheds like Point Peter Brook may not show
any immediate response to decreases in atmospheric deposition. 相似文献
242.
Evaluation of health impacts arising from inhalation of pollutant particles <10 μm (PM10) is an active research area. However, lack of exposure data at high spatial resolution impedes identification of causal associations between exposure and illness. Biomagnetic monitoring of PM10 deposited on tree leaves may provide a means of obtaining exposure data at high spatial resolution. To calculate ambient PM10 concentrations from leaf magnetic values, the relationship between the magnetic signal and total PM10 mass must be quantified, and the exposure time (via magnetic deposition velocity (MVd) calculations) known. Birches display higher MVd (∼5 cm−1) than lime trees (∼2 cm−1). Leaf saturation remanence values reached ‘equilibrium’ with ambient PM10 concentrations after ∼6 ‘dry’ days (<3 mm/day rainfall). Other co-located species displayed within-species consistency in MVd; robust inter-calibration can thus be achieved, enabling magnetic PM10 biomonitoring at unprecedented spatial resolution. 相似文献
243.
DNA strand damage, using the single-cell gel electrophoresis (comet) method, was determined in different-stage embryos of
grass shrimp (Palaemonetes pugio) collected from surface waters of a local estuary near Savannah, Georgia, USA. Late-stage embryos collected from the estuarine
river at midday in the summer or placed in a solar simulator showed extensive DNA strand damage. The solar simulator, which
produced the total irradiance found at midday in the summer at 34°N caused DNA strand damage in embryos similar to that found
in sunlight-exposed embryos. A large increase in cyclobutane pyrimidine dimers (18 cyclobutane pyrimidine dimers per 1000
kilobases) were detected in DNA from the late-stage embryos exposed to the solar simulator for 1 h (solar irradiance of 126 μW
cm−2). DNA repair took place within a few hours when late-stage embryos collected at midday from the river were transferred to
the dark. Early grass-shrimp embryo stages showed no DNA strand damage either after placement in the solar simulator or when
collected at midday in the summer. This lack of solar-damaged DNA in early-stage embryos was probably due to the presence
of high concentrations of carotenoids, which can act as anti-oxidants to prevent damage from activated oxygen species produced
by cells exposed to ultraviolet light. These carotenoids are utilized by the developing embryos, and only low concentrations
of carotenoids were present in late embryo stages.
Received: 24 May 1999 / Accepted: 11 May 2000 相似文献
244.
Mycosporine-like amino acids (MAAs), which occur in diverse taxonomic groups, exhibit in vivo absorption maxima between 310 nm
and 360 nm and may play a photoprotective role against ultraviolet (UV) exposure. Using cultures of colonial Phaeocystis antarctica, we examined the relationship between MAA concentration, in vivo UV absorption, photoprotective (carotenoid) and photosynthetic
pigments, and photosynthetically available radiation (PAR, 350–700 nm). UV absorption was high; chlorophyll-specific absorption,
a
*
ph, at 330 nm ranged from 0.06 to 0.41 m2/mg chlorophyll a. Values of a
*
ph (330) were 4–13 times greater than a
*
ph (676). Mycosporine-glycine, shinorine, and mycosporine-glycine valine are responsible for the strong in vivo UV absorption.
The sum of all MAAs increased with irradiance when normalized to chlorophyll a or carbon concentrations, whereas individual MAAs varied independently from each other. Mycosporine-glycine concentrations
showed no statistically significant change over the range of light intensities, whereas mycosporine-glycine and shinorine
concentrations increased at higher irradiances. The relative fluorescence yield for chlorophyll a was low in the UV region compared to the visible region, implying that absorbed UV radiation (<375 nm) is transferred inefficiently
to chlorophyll a in the reaction center. Quantitative estimates of UV screening by MAAs are attributed to elevated MAA concentrations and
increased diameter at high light.
Received: 31 March 1999 / Accepted: 13 July 2000 相似文献
245.
Sudarshan Kurwadkar Victoria Sicking Barry Lambert Anne McFarlan Forrest Mitchell 《环境科学学报(英文版)》2013,25(2):268-273
Water quality impact due to excessive nutrients has been extensively studied. In recent years, however, micro-pollutants such as pharmaceuticals and hormonal products used in animal agriculture have added an additional impact to overall water quality. Pharmaceuticals used in the poultry, swine, beef, and dairy industries have been detected in various environmental matrices such as, soil, groundwater and surface water. In this study, 26 surface water samples were collected throughout the Bosque River Watershed (BRW) with samples representing a range of land use conditions and locations of major dairy operations. Samples were analyzed using commercially available Enzyme-Linked Immunosorbent Assay test. Of the 26 samples, three samples consistently tested positive for monensin antibiotic with concentration ranging from 0.30 to 3.41 μg/L. These three samples were collected from sites that received varying amount of agriculture wastes (11.7% to 31.3%) and located downstream from sites associated with moderate levels of animal agriculture. The preliminary results suggest that there is a potential for monensin occurrence in the BRW, although initial findings indicate only very low levels. 相似文献
246.
Leslie A. Simms Eva Borras Bradley S. Chew Bruno Matsui Mitchell M. McCartney Stephen K. Robinson Nicholas Kenyon Cristina E. Davis 《环境科学学报(英文版)》2021,33(5):135-147
Trace analysis of volatile organic compounds (VOCs) during wildfires is imperative for environmental and health risk assessment. The use of gas sampling devices mounted on unmanned aerial vehicles (UAVs) to chemically sample air during wildfires is of great interest because these devices move freely about their environment, allowing for more representative air samples and the ability to sample areas dangerous or unreachable by humans. This work presents chemical data from air samples obtained in Davis, CA during the most destructive wildfire in California's history - the 2018 Camp Fire – as well as the deployment of our sampling device during a controlled experimental fire while fixed to a UAV. The sampling mechanism was an in-house manufactured micro-gas preconcentrator (µPC) embedded onto a compact battery-operated sampler that was returned to the laboratory for chemical analysis. Compounds commonly observed in wildfires were detected during the Camp Fire using gas chromatography mass spectrometry (GC–MS), including BTEX (benzene, toluene, ethylbenzene, m+p-xylene, and o-xylene), benzaldehyde, 1,4-dichlorobenzene, naphthalene, 1,2,3-trimethylbenzene and 1-ethyl-3-methylbenzene. Concentrations of BTEX were calculated and we observed that benzene and toluene were highest with average concentrations of 4.7 and 15.1 µg/m3, respectively. Numerous fire-related compounds including BTEX and aldehydes such as octanal and nonanal were detected upon experimental fire ignition, even at a much smaller sampling time compared to samples taken during the Camp Fire. Analysis of the air samples taken both stationary during the Camp Fire and mobile during an experimental fire show the successful operation of our sampler in a fire environment. 相似文献
247.
Sinéad Mitchell Paul O’Dowd Aurora Dimache 《International Journal of Sustainable Engineering》2020,13(3):159-170
ABSTRACT Public discourse frequently cites the damaging activities of large organisations on global environmental issues, but smaller organisations are rarely, if ever, featured. Small and Medium Enterprises (SMEs) make up 99% of all businesses in the EU, cumulatively causing more industrial pollution and producing more waste than larger businesses. However, large companies are more likely to address sustainability issues than smaller ones. SMEs need help to change. In a collaborative approach, an online sustainability framework was developed to overcome the barriers contributing to the slow uptake in environmental management in SMEs. The views of owner-managers were incorporated throughout the development process. Best practice environmental tools and training were identified, which were designed in an SME-friendly way and made available online. This paper describes the development of the pilot Sustainability and Eco-Innovation (SEco) toolkit, followed by an analysis of its use. This research finds that a self-led toolkit was not enough to nudge SMEs to address environmental issues, despite being approved by owner-managers at each step. 相似文献
248.
249.
Carlyle L. Mitchell Economic Consultant Lennox O. Hinds Senior Advisor 《Natural resources forum》1999,23(3):235-244
Because of their economic and environmental vulnerability, small island developing states (SIDS) have peculiar developmental problems that severely affect their ability to implement the measures necessary for attaining sustainable development as recommended in UNCED's Agenda 21. Although this has been recognised by the Commission on Sustainable Development (CSD), and although there has been international acceptance of a SIDS Programme of Action (POA), SIDS have not been the focus of adequate attention by international and donor agencies. As a result, progress toward implementing the POA has been disappointing. This study examines the question of how sustainable management and development of ocean resources can contribute significantly to the achievement of the objectives of the SIDS POA. 相似文献
250.
Two aluminum water treatment residuals (Al-WTRs) from water treatment plants in Manatee County, FL and Punta Gorda, FL were evaluated as potential permeable reactive barrier (PRB) media to reduce groundwater phosphorus (P) losses. Short-term (<24 h) P sorption kinetics and long-term P sorption capacity were determined using batch equilibration studies. Phosphorus desorption was characterized following P loadings of 10, 20, 30, 40 and >70 g kg−1. Sorption and desorption studies were conducted on the <2.0 mm material and three size fractions within the <2.0 mm material. The effect of dissolved organic carbon (DOC) on P retention was determined by reacting Al-WTRs with P-spiked groundwater samples of varying initial DOC concentrations. Phosphorus sorption kinetics were rapid for all size fractions of both Al-WTRs (>98% P sorption effectiveness at shaking times ?2 h). The effect of DOC was minimal at <150 mg DOC L−1, but modest reductions (<22%) in P sorption effectiveness occurred at 587 mg DOC L−1. The P sorption capacities of the Manatee and Punta Gorda Al-WTRs (<2.0 mm) are ∼44 g kg−1 and >75 g kg−1, respectively, and the lifespan of an Al-WTR PRB is likely many decades. Desorption was minimal (<2% of the P sorbed) for cumulative P loadings <40 g kg-l, but increased (<9% of the P sorbed) at cumulative P loads >70 g kg−1. The <2.0 mm Manatee and Punta Gorda Al-WTRs are regarded as ideal PRB media for P remediation. 相似文献