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111.
Geographic patterns of non-carpeted floor dust loading in Syracuse, New York (USA) homes 总被引:1,自引:0,他引:1
Johnson DL Hunt A Griffith DA Hager JM Brooks J Stellalevinsohn H Lanciki A Lucci R Prokhorova D Blount SL 《Environmental geochemistry and health》2009,31(3):353-363
Residential floor dust loading was measured on the smooth floor surface of 488 houses in Syracuse, New York, during the summers
of 2003 and 2004. Using U.S. Environmental Protection Agency (EPA) wipe methods, pre-weighed Ghost Wipes, Lead Wipes, or Whatman
Filters were employed to collect duplicate samples from (predominantly) kitchens. The collection efficiency of the various
media was determined from multiple wipe tests and side-by-side comparisons. The results were normalized and aggregated at
the census tract level to determine whether spatial patterns of dust loading could be observed. Loading was found to be log-normally
distributed, with a geometric mean value of 0.311 g m−2 (29 mg of dust per square foot of floor); 95% of the observations fell in the range of 0.042–2.330 g m−2 (4–216 mg foot−2). The sampling for floor dust loading shows some bias for day of the week in which visits to the residential properties were
made. After a first-order correction for this effect, results were aggregated by census tract and mapped in a geographic information
system (GIS); strong spatial patterns can be identified in an inverse distance weighted mapping. The geographic patterns exhibit
a strong correlation with socio-economic/demographic covariates extracted from the 2000 census summaries. Dust mass on the
floors is positively correlated with renter-occupied properties and family size; it is negatively correlated with measures
of household income. 相似文献
112.
Retention of heavy metals in a Typic Kandiudult amended with different manure-based biochars 总被引:3,自引:0,他引:3
Uchimiya M Cantrell KB Hunt PG Novak JM Chang S 《Journal of environmental quality》2012,41(4):1138-1149
Although nutrient-rich manure biochars are expected to be an effective heavy metal stabilizer in agricultural and contaminated soils, systematic studies are lacking to predict the influence of manure variety and pyrolysis temperature on metal-binding potentials. In this study, biochars produced from five manure varieties (dairy, paved feedlot, swine solids, poultry litter, and turkey litter) at two pyrolytic temperatures (350 and 700°C) were examined for the stabilization of Pb, Cu, Ni, and Cd in a weathered, acidic Norfolk loamy sand (fine-loamy, kaolinitic, thermic, Typic Kandiudult). Equilibrium concentrations in the aqueous phase were determined for heavy metals (Cu, Ni, Cd, and Pb) and additional selected elements (Na, P, S, Ca, Mg, Al, and K); these were analyzed by positive matrix factorization to quantitatively determine the factors responsible for the biochar's ability to bind the selected heavy metals in soil. Concurrently with the greatest increase in pH and highest equilibrium Na, S, and K concentrations, poultry litter, turkey litter, and feedlot 700°C biochar exhibited the greatest heavy metal retention. In contrast, manure varieties containing disproportionately high (swine) and low (dairy) ash, P, and other elements were the least effective stabilizers. Regardless of the manure type, proton nuclear magnetic resonance analyses showed the removal of leachable aliphatic and nitrogen-containing heteroaromatic functional groups at the higher (700°C) pyrolysis temperature. Consistently greater Cu retention by the 700°C biochar indicated the mobilization of Cu by 350°C biochar-born dissolved organic carbon; however, the influence of other temperature-dependent biochar characteristics cannot be ruled out. 相似文献
113.
The frequency of air monitoring necessary to characterize an air pollutant for a given time period and area is an important problem. This paper deals with the precision of measuring an air pollutant concentration. Past research has shown that the distribution of many air pollutants can be described as log-normal. Using this result equations have been developed that predict the precision of the sample mean of the air pollutant as a function of: the frequency of sampling, the standard deviation of the logarithms of the air pollution measurements, and the level of confidence. An illustration is given to demonstrate their use. The equations are used to compare sampling plans. Tables are presented showing the precision associated with five sampling plans, for three geometric standard deviations, for three levels of confidence, and five periods of time over which the sampling plan is employed. In an Appendix a mathematical development is presented showing the theoretical derivation of the equations. With these equations the precision of a sampling plan can be determined for any level of confidence or period of time. All that is needed is an estimate of the geometric standard deviation for the air pollution measurements. Finally, the theoretical model is applied to air monitoring data that were collected at Roselawn School in Cincinnati, Ohio, between January 3, 1968, and April 1, 1968. The 90-day period was divided into three 30-day periods. All possible samples of size three were taken from each of the 30-day periods and their means and confidence intervals were calculated. The number of times the confidence intervals contained the true means was determined. The actual number of samples accepted as having contained the true mean, for the 80, 90, 95, and 9 9% level of confidence compared favorably with the theoretical. It is concluded that the model adequately described the behavior of air pollutants. 相似文献
114.
In the present study 670 individuals of Gonatus onyx (Cephalopoda: Teuthoidea) were observed in Monterey Bay, California from a remotely operated vehicle. The vertical distribution
of this species was bimodal, with peaks at 400 and 800 m depth during the day and 300 and 500 m during the night. The bimodal
distribution reflects a life stage shift between younger, schooling juveniles living in shallower water and older, solitary
adults which live deeper. Ontogenetic changes in behavior associated with this life stage shift are reflected in the physiology
of the organisms as well. Both aerobic and anaerobic metabolism, as estimated using mitochondrial and glycolytic enzymes,
decline with increasing body mass, suggesting reduced locomotory capacity in deeper-living adults. Oxygen consumption rates
were also determined in relation to oxygen partial pressure. Oxygen consumption regulation was similar between juvenile and
adult squids. The critical oxygen partial pressures (29 to 30 mmHg) correspond precisely to the oxygen concentrations found
at the depth of maximal abundance for day and night populations of juveniles and adults, respectively. Behavioral and physiological
changes with ontogeny of G. onyx are believed to result from reduced visual predator/prey interactions in the light-limited deep sea.
Received: 7 February 1999 / Accepted: 26 January 2000 相似文献
115.
Environmental Fluid Mechanics - Passive ventilation of buildings at night forms an essential part of a low-energy cooling strategy, enabling excess heat that has accumulated during the day to... 相似文献
116.
Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite (alpha-FeOOH) of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover (Trifolium incarnatum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], hairy vetch (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm, and phenolic acid content. A 10-d laboratory microbial decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions. There was a decrease in the MWAP values of the DOM samples following sorption to goethite. In many cases the reduction in MWAP was large, indicating a strong preference by goethite for the higher MWAP DOM fractions. The results of this laboratory-based research demonstrate that microbial processes affect the chemical characteristics of DOM which may affect the distribution of soil organic C pools. 相似文献
117.
118.
In the buoyancy and turbulence-driven atmospheric circulations (BTDAC) that occur over urban areas where the approach means wind speeds are very low (less than turbulent fluctuations and typically < 3 m/sec), the surface temperatures are significantly higher than those in the external rural areas, and the atmosphere above the mixing layer is stably stratified. In this paper, the mechanisms of BTDAC formation are studied through laboratory experiments and modelling, with additional low-level inflow from external rural areas and a divergent outflow in the opposite direction in the upper part of the mixed layer. Strong turbulent plumes in the central region mix the flow between lower and higher levels up to the inversion height. There are shear-driven turbulent eddies and weaker buoyant plumes around the periphery of the urban area. As the approach flow is very weak, the recirculating streamlines within the dome restrict the ventilation, and the dispersion of pollution emitted from sources below the inversion height leading to a rise in the mean concentration. Low-level air entrained from rural areas can, however, improve ventilation and lower this concentration. This trend can also be improved if the recirculating structure of the BTDAC flow pattern over urban areas breaks down as a result of the surface temperature distribution not being symmetrical, or as the approach wind speed increases to a level comparable with the mean velocity of circulation, or (except near the equator) the urban area is large enough that the Coriolis acceleration is significant. 相似文献
119.
Hassan I.Al-Mohannadi Chris O. Hunt Adrian P. Wood 《Ambio-人类环境杂志》2003,32(5):362-366
卡塔尔由于社会经济高速发展,人口大量增加,水资源存在严重问题.市政给水依靠高成本和不可持续的海水淡化,而对用水几乎没有限制,卡塔尔本国居民不用付水费,外国移居者付补助性的水费--大约1/3的成本费用,因此人们很少意识到水的真正成本,用水极其浪费.这篇文章讨论的是卡塔尔的用水趋势及与可持续用水有关的问题.一个针对卡塔尔社会各阶层的问卷调查了人们对水的意识和态度,结果显示,原有为了控制用水量而做的努力,如提高意识宣传活动、法律上的限制及水费是无效的.问卷评价了对限制用水可采取的措施的反应,其中有提高公众意识、使用法律措施和提高水费,从中提出一系列改变政策的建议,促使卡塔尔给水工业进入可持续发展阶段. 相似文献
120.
The morphology and function of structures important to energy acquisition were studied from spawning to the stage of transformation of larva to pelagic juvenile in Atlantic cod, Gadus morhua L., from December 1991 to July 1992. Fertilized eggs produced by adult fish from two genetically discrete populations (Newfoundland and Scotian Shelf) were raised under similar conditions in the laboratory at temperatures of 5 and 10°C. Subsamples of larvae were removed from cultures daily for 10 d, and then less frequently, and fixed for light microscopy and scanning electron microscopy. Nine functional morphological landmarks important to feeding, respiration and locomotion were chosen from observation of 280 ind. These landmarks defined 12 major developmental stages, from hatching to the pelagic juvenile stage. One of the feeding landmarks, intestinal stage, varied as a function of age and size and the variance in development was higher at 10°C than at 5°C; Newfoundland larvae developed more complex intestines than did Scotian Shelf larvae. In addition, Newfoundland larvae had significantly higher growth rates than those of Scotian Shelf larvae. Despite the higher growth rates and greater structural complexity of the intestine in Newfoundland larvae, the rate of yolk utilization was not significantly different between Newfoundland and Scotian Shelf larvae. Staging of respiratory landmarks showed that the gill arches were probably used preferentially in feeding while respiration was cutaneous. The gills, operculum and gill rakers developed late in larval life and accompanied the transition from cutaneous to branchial respiration. In the yolk-sac period, development of feeding and respiratory structures may be largely genetically controlled. During exogenous feeding, extrinsic factors also become important, as shown by the size and age-independent variation in intestinal development of larval cod raised at different temperatures. 相似文献