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51.
The PM(2.5) concentration and its elemental composition were measured in the Cincinnati metropolitan area, which is characterized by intense highway traffic. The spatial and temporal variations were investigated for various chemical elements that contributed to the PM(2.5) fraction during a 1-year-long measurement campaign (December 2001-November 2002). The ambient aerosol monitoring was performed in 11 locations around the city during nine measurement cycles. During each cycle, four Harvard-type impactors were operating in parallel in specific locations to explore various factors affecting the PM(2.5) elemental concentrations. The sampling was performed during business days, thus assuring traffic uniformity. The 24-h PM(2.5) samples were collected on Teflon and quartz filters. Teflon filters were analyzed by X-ray fluorescence (XRF) analysis while quartz filters were analyzed by thermal-optical transmittance (TOT) analysis. In addition to PM(2.5) measurements, particle size-selective sampling was performed in two cycles using micro-orifice uniform deposit impactor; the collected fractionated deposits were analyzed by XRF. It was found that PM(2.5) concentration ranged from 6.70 to 48.3 mug m(-3) and had low spatial variation (median coefficient of variation, CV=11.3%). The elemental concentrations demonstrated high spatial variation, with the median CV ranged from 38.2% for Fe to 68.7% for Ni. For traffic-related trace metals, the highest concentration was detected in the city center site, which was close to a major highway. The particle size selective measurement revealed that mass concentration of the trace metals, such as Zn, Pb, Ni, as well as that of sulfur reach their peak values in the particle size range of 0.32-1.0 mum. Meteorological parameters and traffic intensity were not found to have a significant influence on the PM(2.5) elemental concentrations.  相似文献   
52.
A sequencing batch reactor was used to study the possibility of harvesting polyhydroxyalkanoate (PHA) from enhanced biological phosphorus removal (EBPR) processes without compromising treatment quality. Because, in EBPR, the highest PHA concentrations are observed after exposure of the sludge to anaerobic conditions, PHA accumulation was evaluated with collection of waste activated sludge (WAS) at the end of the anaerobic stage, in addition to the traditional removal after the aerobic stage. The system achieved good phosphorus removal, regardless of the point of WAS collection. When sludge was harvested at the end of the anaerobic stage, the PHA content of the sludge ranged from 7 to 16 mg PHA/100 mg mixed liquor volatile suspended solids. Although this level of PHA production is below levels obtained with pure cultures, the demonstrated ability to harvest PHA, while simultaneously satisfying phosphorus removal in an EBPR process, is a key initial step towards of the use of wastewater treatment plants for PHA production.  相似文献   
53.
Font R  Esperanza M  García AN 《Chemosphere》2003,52(6):1047-1058
Lignin samples, sub-product in the Kraft process of cellulose from eucalyptus wood, were burnt in a laboratory scale furnace at different residence temperatures and with distinct fuel-rich atmospheres. The yields of CO, CO(2), eight light hydrocarbons (methane, ethylene, ethane, propylene, acetylene, butane, etc.) and 60 semi-volatile+volatile compounds (benzene, toluene, ethylbenzene, styrene, indene, naphthalene, dibenzofuran, phenanthrene, chrysene, etc.) were determined, with nominal reactor temperatures between 800 and 1100 degrees C and residence times of the volatiles evolved and formed between 4 and 7 s. The collection of the gases and volatiles evolved was carried out with a Tedlar bag and by XAD-4 resin respectively, comparing the data obtained in both cases. The emission factor (mg/kg) of the CO was between 2500 and 90000, and under the poor-oxygen atmosphere, the emission factors of many by-toxic products were greater than 100 mg/kg. A pyrolysis run was also performed, obtaining emission factors between 30 and 3000 mg/kg, facilitating its identification. The behaviour of different compounds in the combustion runs was discussed considering three groups in accordance with their stability vs. oxygen, and two groups vs. temperature.  相似文献   
54.
55.
An on-line solid phase extraction liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method for the determination of 12 antimicrobials in sediment and surface water was developed and validated. Furthermore, the spatial and temporal antimicrobials distributions in the sediment and in the water of four fish farms located in the hydroelectric dam of Ilha Solteira Reservoir in Brazil were investigated over four seasons in three sampling sites: at the fish cages, 100 and 1,000 m downstream far from the cages. The method was performed using an Agilent Zorbax 80 SB-C8 column (9.4 × 15 mm, 5 µm) as the loading column, and the Agilent Zorbax Eclipse Plus C18 column (3.0 × 100 mm, 3.5 µm) as a separation column within a run time of 13 min. The limits of quantification were less than 9 ng·L?1 for the antibiotics in water and 16 µg·kg?1 in sediment; the recovery ranged from 80 to 119%, with a variation coefficient less than 11%, and the repeatability was lower than 15%. Oxytetracycline was found in the water in all sample seasons. However, florfenicol was identified in April and October 2013 and January 2014, and tetracycline was present in July 2013. Regarding the sediment, oxytetracycline and tetracycline were found in all sampling periods, but chlortetracycline was only identified in January 2014. The spatial distribution of antimicrobials showed that the main pollution source came from the fish farms. This study demonstrated that the proposed method is reliable for the monitoring of antimicrobials in water and sediments and it showed contamination in both matrices from Ilha Solteira Reservoir.  相似文献   
56.
The effect of the characteristics of the surface on the phototransformation of acridine, one of the most abundant azapolycyclic compounds encountered in urban atmospheres, and of one of its principal photoproducts, acridone, was studied when adsorbed onto models of the atmospherice particulate matter. For this purpose, relative photodegradation rates were determined from absorption or emission intensities as a function of irradiation times, and some products were isolated and characterized. The relative photodegradation rates of adsorbed acridine show the tendency (NH(4))(2) SO(4) > MgO > Al(2)O(3) >SiO(2). In general, the rates decrease as the fraction of protonated acridine species on the surface increases in MgO, Al(2)O(3), and SiO(2), except for (NH(4))(2) SO(4) where a fast surface reaction occurs. Oxygen reduces the photodestruction rates by as much as 40 to 60% when compared to an inert atmosphere, implying the participation of an acrideine triplet state in the transformation processes on all surfaces except on (NH(4))(2)SO(4). Acridone, a major product, undergoes a photoinduced tautomerization to 9-hydroxy acridine. The formation of a dihydrodiol, another photoproduct of acridine, is suggested by comparison to reported spectral properties of these compounds. This is formed through a singlet oxygen reaction. Photoproducts showing the absence of the narrow absorption band of 250 nm, characteristic of the pi -->pi* transition in tricyclic aromatics, were detected in small yields but not identified. These results suggest possible photochemical transformation pathways that could lead to the ultimate fate of these pollutants in the environment.  相似文献   
57.
Ecohealth is a process for identifying key environmental determinants causing mortality or morbidity and combating them by mobilizing multiple social sectors. Evolving out of the concept of environmental health, ecohealth provides a framework for long‐term sustainability. The health outcomes anticipated by environmental interventions are part of a long‐term agenda and require fundamental groundwork for the growth of community‐driven development. Building long‐term sustainability requires that two key approaches be developed through ecohealth. The first is the strengthening of local community institutions, whether formal or informal. The second is building financial mechanisms that are more diversified and less reliant on a single donor. As a result, the ecohealth system provides an opportunity for foundations to empower communities, build cross‐cutting cooperation, and gain knowledge through projects. If people's environmental behaviour is to change and be sustained in the long term to produce desired health outcomes, this will require all members of society to be capable of functioning within the existing institutional infrastructure. This means that not only do formal institutions need to become more accessible but also that concepts relating to local informal institutions must be incorporated into ecohealth projects. It is imperative that we identify and understand relevant local institutions and how they can be transformed so that new environmental forms of behaviour can be sustained and result in positive health outcomes. The intersection of environmental and health concerns provides an ideal area in which the gap between government and civil society can be bridged — not only providing solutions to ecohealth concerns, but building government capacity in general and making these positive changes sustainable in the long term. This article is a case study, based on several United Nations Foundation grants. It outlines the significance of traditional community organizations, the breadth of their long‐term relations with communities, their resources, and the adoption of sustained forms of behaviour. In addition, the article highlights the role that international foundations can play in creating innovative financing mechanisms through community‐based foundations.  相似文献   
58.
Environmental Science and Pollution Research - Recalcitrant dyes found in textile wastewater represent a threat for sustainable textile production due to their resistance to conventional...  相似文献   
59.
Environment, Development and Sustainability - Current trends such as imminent overpopulation and the take-make-waste economic model are largely responsible for the planet’s dire situation....  相似文献   
60.
Many hospitals or health care facilities have faced financial difficulties and thus they have attempted to find cost-effective treatment and disposal methods of their regulated medical wastes (RMWs). This study investigated generation volume and sources, composition, and treatment and disposal methods for RMWs obtained from three out of the five typical city hospitals in Massachusetts for which we could obtain relevant data on medical waste. Also, this study compared the generation patterns and amounts of RMWs between the hospital and the medical school. The yearly operational treatment and disposal costs of RMWs based on different treatment and disposal methods were analyzed for one hospital. The most cost-effective option of four different treatment and disposal options studied was to combine on-site incineration and microwave technologies. Finally, this study identified measures for the effective waste characterization methods for the reduction of treatment and disposal costs of RMWs. By careful exclusion of non-RMW from RMW waste streams, hospitals can reduce the RMW volume that requires special treatment and reduce disposal costs.  相似文献   
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