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381.
Bielmyer GK Arnold WR Tomasso JR Isely JJ Klaine SJ 《Environmental monitoring and assessment》2012,184(5):2797-2804
Copper sheeting is a common roofing material used in many parts of the world. However, copper dissolved from roof sheeting
represents a source of copper ions to watersheds. Researchers have studied and recently developed a simple and efficient model
to predict copper runoff rates. Important input parameters include precipitation amount, rain pH, and roof angle. We hypothesized
that the length of a roof also positively correlates with copper concentration (thus, runoff rates) on the basis that runoff
concentrations should positively correlate with contact time between acidic rain and the copper sheet. In this study, a novel
system was designed to test and model the effects of roof length (length of roof from crown to the drip edge) on runoff copper
concentrations relative to rain pH and roof angle. The system consisted of a flat-bottom copper trough mounted on an apparatus
that allowed run length and slope to be varied. Water of known chemistry was trickled down the trough at a constant rate and
sampled at the bottom. Consistent with other studies, as pH of the synthetic rainwater decreased, runoff copper concentrations
increased. At all pH values tested, these results indicated that run length was more important in explaining variability in
copper concentrations than was the roof slope. The regression equation with log-transformed data (R
2 = 0.873) accounted for slightly more variability than the equation with untransformed data (R
2 = 0.834). In log-transformed data, roof angle was not significant in predicting copper concentrations. 相似文献
382.
Muñoz J Mudge SM Loyola-Sepulveda R Muñoz G Bravo-Linares C 《Journal of environmental monitoring : JEM》2012,14(6):1671-1676
A pipe rupture during unloading led to a spillage of 350-700 tonnes of Ca?o Limon, a light sweet crude oil, into San Vicente Bay in 2007. Initial clean-up methods removed the majority of the oil from the sandy beaches although some oil remained on the rocky shores. It was necessary for the responsible party to clean the spilled oil even though at this location there were already crude oil hydrocarbons from previous industrial activity. A biosolvent based on vegetable oil derivatives was used to solubilise the remaining oil and a statistical approach to source apportionment was used to determine the efficacy of the cleaning. Sediment and contaminated rock samples were taken prior to cleaning and again at the same locations two days after application of the biosolvent. The oil was extracted using a modified USEPA Method 3550B. The alkanes were quantified together with oil biomarkers on a GC-MS. The contribution that Ca?o Limon made to the total oil hydrocarbons was calculated from a Partial Least Squares (PLS) analysis using Ca?o Limon crude oil as the source. By the time the biosolvent was applied, there had already been some attenuation of the oil with all alkanes 相似文献
383.
Bruce Thompson J. Ananda Ranasinghe Sarah Lowe Aroon Melwani Stephen B. Weisberg 《Environmental monitoring and assessment》2013,185(3):2281-2295
The spatial and temporal distribution of macrobenthic assemblages in the San Francisco Estuary and Sacramento–San Joaquin River Delta were identified using hierarchical cluster analysis of 501 samples collected between 1994 and 2008. Five benthic assemblages were identified that were distributed primarily along the salinity gradient: (1) a polyhaline assemblage that inhabits the Central Bay, (2) a mesohaline assemblage that inhabits South Bay and San Pablo Bay, (3) a low-diversity oligohaline assemblage primarily in Suisun Bay, (4) a low-diversity sand assemblage that occurs at various locations throughout the Estuary, and (5) a tidal freshwater assemblage in the Delta. Most sites were classified within the same assemblage in different seasons and years, but a few sites switched assemblage designations in response to seasonal changes in salinity from freshwater inflows. 相似文献
384.
Trace metals in sediments of Southeast Pacific Fjords, north region (42.5 degrees to 46.5 degrees S)
Analyses of trace metals in benthic sediments from selected fjords and channels between 41 degrees 30' and 46 degrees 50'S, 75 degrees -72.3 degrees W were made after the CIMAR 1 Fjords expedition co-ordinated by CONA-Chile in 1995; the metals analyzed include Ba, Cd, Co, Cr, Cu, Ni, Pb, Sr, V and Zn. The objective of this study was to establish baseline values for these metals and to compare them with similar studies made in comparable, but geographically distinct, environments. Box core samples were collected at 35 stations and metal analysis was by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) using the MESS-2 reference standard. The ranked abundance by metal was Ba > Sr > V > Zn > Cr > Cu approximately Ni approximately Pb > Co > Cd; these metals were not homogenous across the region and coefficients of variation were >10%. There were distinct groupings by metal and geographical area including the fjords, basins and channels. Depth profiles of the metal concentrations also varied spatially, e.g. Guafo, Laguna San Rafael, Moraleda, Corcovado, Quitralco, and Jacaf were predominantly homogeneous with depth profiles indicative of pristine systems experiencing few human impacts. In contrast, Aysen, Cupquelan and Puyuguapi Fjords had higher concentrations towards the surface, indicating elevated inputs in recent years. No major differences in metal content of the sediments were observed when compared with values from comparable natural systems in the northern hemisphere. Principal component analysis (PCA) grouped several seemingly isolated locations as having the same metal signature and indicated the pattern of dispersion across the region. 相似文献
385.
Stephen C. James Donald E. Sanning 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1178-1184
The problem of contamination to land and groundwater from improper handling of hazardous materials/ waste is faced by all countries. Also, the need for reliable, cost-effective technologies to address this problem at contaminated sites exists throughout the world. Many countries have only started to develop new innovative/ alternative technologies while others have already started to apply these technologies to the cleanup of contaminated sites. The purpose of this NATO/ CCMS (North Atlantic Treaty Organization/Committee for the Challenges to Modern Society) Pilot Study is to discuss and evaluate new innovative/alternative technologies and/or existing systems that may be applicable to the cleanup of contaminated sites. Through this pilot study, the exchange of information on new and existing technologies for dealing with problem hazardous waste sites is promoted. The pilot study is made up of an international group of experts drawn from the participating countries. The study, which was initiated in 1986, is planned to last five years. It is piloted by the United States and copiloted by the Federal Republic of Germany (FRG) and The Netherlands. This report includes an overview and history of the NATO/CCMS Pilot Study, but it primarily presents a documentation of the NATO/CCMS Second International Conference on the Demonstration of Remedial Action Technologies for Contaminated Land and Groundwater held in Bilthoven, The Netherlands on November 7-11,1988. 相似文献
386.
Amos Turk Jack I. Morrow Stephen H. Stoldt Warren Baecht 《Journal of the Air & Waste Management Association (1995)》2013,63(7):383-385
It has been previously shown that the desorption of either a chemisorbed or a physically adsorbed gas can be enhanced by the subsequent introduction of a foreign gas. Under conditions in which desorption recovery of butane from activated, carbon was 50 to 65%, subsequent adsorption of CCl4 enhanced the recovery of butane to 100%. Recovery of CCl2F2, originally 79%, was enhanced to 99% by the same method. The method of enhanced desorption was applied to the recovery of samples from activated carbons exposed to atmospheres in Chicago, New Orleans, Philadelphia, Washington, D. C, and Cincinnati. Three different types of carbons, characterized by different distributions of pore diameters, were used simultaneously in the Cincinnati sampling. In general, the enhanced desorption technique was advantageous in providing analytical information on adsorbed samples recovered from carbon media. The enhancement effect is especially marked with hydrocarbon material. The effects of these structural attributes of the carbon media are evaluated by detailed consideration of infrared absorptions. 相似文献
387.
388.
James J. Huntzicker Emily K. Heyerdahl Stephen R. McDow John A. Rau Wayne H. Griest Carolyn S. MacDougall 《Journal of the Air & Waste Management Association (1995)》2013,63(6):705-709
Organic and elemental carbon and a number of carboxylic acids and n-alkanes were measured in aerosol samples collected at three sites in the Ohio River Valley between October 1980 and August 1981. Approximately 100 filters were analyzed for organic and elemental carbon for each site. For the 11-month period organic and elemental carbon comprised about 19 percent of the total aerosol mass with about two-thirds of the carbon as organic. Regression analysis showed that the principal source of organic carbon was combustion. The measurements of the specific organic compounds indicated a weak biogenic component to the organic aerosol. 相似文献
389.
William F. Jaynes Stephen A. Boyd 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1649-1653
Homoionic trimethylphenylammonium (TMPA)- and tetramethylammonium (TMA)-clays were prepared by Ion-exchange reactions using two smectite clays that differed in their cation exchange capacities and surface charge densities. These clays are referred to as a low-charge (SAC) and high-charge (SWa)-smectite. The organo-clays were evaluated as adsorbents of water soluble aromatic hydrocarbons including benzene, toluene, ethylbenzene, p-xylene, butylbenzene, and naphthalene. All of the aromatic hydrocarbons tested were effectively removed from water by the low-charge TMPA-smectite. The low-charge TMA-smectite was an effective adsorbent for benzene but was ineffective in the removal of the alkylbenzenes and naphthalene from water. The effect of surface charge on the adsorption properties of TMPA-smectite was pronounced. The uptake of benzene and toluene by the high-charge TMPA-smectite was greatly reduced as compared to the low-charge TMPAsmectite. These results suggest the utility of TMPA-smectite as a liner material for petroleum storage containers and waste disposal reservoirs. The use of TMPA-smectite in conjunction with Na-smectite would provide a barrier with the ability to impede the flow of water and to effectively adsorb dissolved organic contaminants. 相似文献
390.
Steven D. Reynolds Charles L. Blanchard Stephen D. Ziman 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1452-1470
Abstract Analyses of ozone (O3) measurements in conjunction with photochemical modeling were used to assess the feasibility of attaining the federal 8-hr O3 standard in the eastern United States. Various combinations of volatile organic compound (VOC) and oxides of nitrogen (NOx) emission reductions were effective in lowering modeled peak 1-hr O3 concentrations. VOC emissions reductions alone had only a modest impact on modeled peak 8-hr O3 concentrations. Anthropogenic NOx emissions reductions of 46–86% of 1996 base case values were needed to reach the level of the 8-hr standard in some areas. As NOx emissions are reduced, O3 production efficiency increases, which accounts for the less than proportional response of calculated 8-hr O3 levels. Such increases in O3 production efficiency also were noted in previous modeling work for central California. O3 production in some urban core areas, such as New York City and Chicago, IL, was found to be VOC-limited. In these areas, moderate NOx emissions reductions may be accompanied by increases in peak 8-hr O3 levels. The findings help to explain differences in historical trends in 1- and 8-hr O3 levels and have serious implications for the feasibility of attaining the 8-hr O3 standard in several areas of the eastern United States. 相似文献