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471.
Todd AS McKnight DM Jaros CL Marchitto TM 《Environmental monitoring and assessment》2007,130(1-3):111-127
In-situ caged rainbow trout (Oncorhynchus mykiss) studies reveal significant fish toxicity and fish stress in a river impacted by headwater acid rock drainage (ARD). Stocked
trout survival and aqueous water chemistry were monitored for 10 days at 3 study sites in the Snake River watershed, Colorado,
U.S.A. Trout mortality was positively correlated with concentrations of metals calculated to be approaching or exceeding conservative
toxicity thresholds (Zn, Mn, Cu, Cd). Significant metal accumulation on the gills of fish stocked at ARD impacted study sites
support an association between elevated metals and fish mortality. Observations of feeding behavior and significant differences
in fish relative weights between study site and feeding treatment indicate feeding and metals-related fish stress. Together,
these results demonstrate the utility of in-situ exposure studies for stream stakeholders in quantifying the relative role of aqueous contaminant exposures in limiting stocked
fish survival. 相似文献
472.
Mercury(Hg)ranks number three,after arsenic(As)and lead(Pb),on the Substance Priority List of the Agency for Toxic Substances and Disease Registry(ATSDR,2019).M... 相似文献
473.
474.
Chris M. Frampton Case J. Pekelharing Ian J. Payton 《Environmental monitoring and assessment》2001,72(3):227-234
A subjective visual assessment of foliage density is the mostwidely used rapid method of determining forest health. Forthese assessments to be ecologically meaningful they must bereliable (have low inter- and intra-observer variability) andreadily relate to a measure of physiological or physicalstress. A simple rapid method for assessing percent foliagedensity in lower stature trees is described. This method haslow inter-observer variability (standard deviation betweenobservers=8.6%) and therefore, minimizes the risk ofconfounding the effects of different observers with genuinechanges in density. The percentage changes in this measure offoliage density correlate well with percentage changes inbiomass, allowing a ready interpretation of observed changes.The technique does not specifically identify the cause of themeasured changes, however, with appropriate additionalmeasures this problem may be overcome. 相似文献
475.
A developed instantaneous emission model is applied to predict emission factors for small vehicle fleets for quality assessment.
Extensive vehicle measurements of pre-Euro-1 gasoline, Euro-3 gasoline, and Euro-2 diesel vehicles are available. The data
were used to develop individual vehicle emission models for each car. The prediction quality for each vehicle category was
determined by averaging the results obtained from the individual vehicle models. The results show that the prediction quality
is improved in comparison with the individual vehicles, even with a small number of vehicles in a specific category. This
indicates that the errors in the individual models are mainly random and that prediction quality, when applied to fleets of
cars, is exceptionally high. 相似文献
476.
477.
Adjei Mensah Isaac Sun Mei Gao Cuixia Omari-Sasu Akoto Yaw Sun Huaping Ampimah Benjamin Chris Quarcoo Alfred 《Environmental science and pollution research international》2020,27(31):38674-38694
Environmental Science and Pollution Research - The main aim of this current study is to empirically scrutinize the determinants of energy consumption for 24 African countries sub-grouped into three... 相似文献
478.
Christian Seigneur Betty Pun Prasad Pai Jean-François Louis Paul Solomon Chris Emery 《Journal of the Air & Waste Management Association (1995)》2013,63(4):588-599
ABSTRACT Guidance for the performance evaluation of three-dimensional air quality modeling systems for particulate matter and visibility is presented. Four levels are considered: operational, diagnostic, mechanistic, and probabilistic evaluations. First, a comprehensive model evaluation should be conducted in at least two distinct geographical locations and for several meteorological episodes. Next, streamlined evaluations can be conducted for other similar applications if the comprehensive evaluation is deemed satisfactory. In all cases, the operational evaluation alone is insufficient, and some diagnostic evaluation must always be carried out. Recommendations are provided for designing field measurement programs that can provide the data needed for such model performance evaluations. 相似文献
479.
Seong Suk Park Kathleen Kozawa Scott Fruin Steve Mara Ying-Kuang Hsu Chris Jakober 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1046-1056
ABSTRACT Fuel-based emission factors for 143 light-duty gasoline vehicles (LDGVs) and 93 heavy-duty diesel trucks (HDDTs) were measured in Wilmington, CA using a zero-emission mobile measurement platform (MMP). The frequency distributions of emission factors of carbon monoxide (CO), nitrogen oxides (NOx), and particle mass with aerodynamic diameter below 2.5 μm (PM2.5) varied widely, whereas the average of the individual vehicle emission factors were comparable to those reported in previous tunnel and remote sensing studies as well as the predictions by Emission Factors (EMFAC) 2007 mobile source emission model for Los Angeles County. Variation in emissions due to different driving modes (idle, low- and high-speed acceleration, low- and high-speed cruise) was found to be relatively small in comparison to intervehicle variability and did not appear to interfere with the identification of high emitters, defined as the vehicles whose emissions were more than 5 times the fleet-average values. Using this definition, approximately 5% of the LDGVs and HDDTs measured were high emitters. Among the 143 LDGVs, the average emission factors of NOx, black carbon (BC), PM2.5, and ultrafine particle (UFP) would be reduced by 34%, 39%, 44%, and 31%, respectively, by removing the highest 5% of emitting vehicles, whereas CO emission factor would be reduced by 50%. The emission distributions of the 93 HDDTs measured were even more skewed: approximately half of the NOx and CO fleet-average emission factors and more than 60% of PM2.5, UFP, and BC fleet-average emission factors would be reduced by eliminating the highest-emitting 5% HDDTs. Furthermore, high emissions of BC, PM2.5, and NOx tended to cluster among the same vehicles.
IMPLICATIONS This study presents the characterization of on-road vehicle emissions in Wilmington, CA, by sampling individual vehicle plumes. Approximately 5% of the vehicles were high emitters, whose emissions were more than 5 times the fleet-average values. These high emitters were responsible for 30% and more than 50% of the average emission factors of LDGVs and HDDVs, respectively. It is likely that as the overall fleet becomes cleaner due to more stringent regulations, a small fraction of the fleet may contribute a growing and disproportionate share of the overall emissions. Therefore, long-term changes in on-road emissions need to be monitored. 相似文献
480.
Monitoring of cyclic volatile methylsiloxanes (cVMS) carried out at Anglian Water’s Broadholme sewage treatment plant (STP) is described. The method deployed used headspace gas chromatography/mass spectrometry (HS-GC/MS) and the addition of isotopically labelled cVMS to correct for partitioning in samples containing high levels of particulate and dissolved organic carbon. The method was capable of measuring cVMS in raw sewage samples, with recoveries of 80%, 85% and 71% respectively, for D4, D5 and D6. The limit of quantification was 0.2 μg L−1 for all three substances. Recoveries close to 100% were observed for all cVMS spiked into treated effluent (LOQ = 0.01 μg L−1). Despite the volatile nature of cVMS and its ubiquitous presence in the ambient atmosphere, the methods deployed showed excellent recoveries, reproducibility and quantification limits. A distinct diurnal variation in cVMS concentration, probably linked with the use of personal care products was observed for raw sewage but not in treated sewage effluent. The estimated per capita consumption of D5 (∼2.7 mg cap−1 d−1) derived for the population served by this plant was significantly lower than that derived in the Environment Agency (UK) risk assessment (11.6 mg cap−1 d−1). The cVMS were highly removed during sewage treatment with efficiencies greater than 98%. The methods and findings of this pilot study can be used as the basis for future studies on the fate of cVMS substances in STPs. 相似文献