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Результаты 701-710 из 2,459
Hierarchy of factors exerting an impact on nutrient load of the Baltic Sea and sustainable management of its drainage basin
2014
Kiedrzyńska, Edyta | Jóźwik, Adam | Kiedrzyński, Marcin | Zalewski, Maciej
The aim of the paper was to evaluate 23 catchment factors that determine total phosphorus and total nitrogen load to the Baltic Sea. Standard correlation analysis and clustering were used. Both phosphorus and nitrogen loads were found to be positively related to the number of pigs and the human population associated with wastewater treatment plants (WWTPs) per km2, while the number of cattle and agricultural area were found to influence nitrogen rather than phosphorus load, and the area of forests is negatively related to loads of both nutrients. Clustering indicates an overall north–south pattern in the spatial co-occurrence of socio-ecological factors, with some exceptions discussed in the paper. Positive steps in the Baltic Sea region have already been taken, but much remains to be done. The development of coherent response policies to reduce eutrophication in the Baltic Sea should be based on a comprehensive knowledge base, an appropriate information strategy and learning alliance platform in each drainage river catchments.
Показать больше [+] Меньше [-]Australia’s pesticide environmental risk assessment failure: The case of diuron and sugarcane
2014
Holmes, Glen
In November 2012, the Australian Pesticide and Veterinary Medicines Authority (APVMA) concluded a 12year review of the PSII herbicide diuron. One of the primary concerns raised during the review was the potential impact on aquatic ecosystems, particularly in the catchments draining to the Great Barrier Reef. The environmental risk assessment process used by the APVMA utilised a runoff risk model developed and validated under European farming conditions. However, the farming conditions in the sugarcane regions of the Great Barrier Reef catchments have environmental parameters beyond the currently validated bounds of the model. The use of the model to assess environmental risk in these regions is therefore highly inappropriate, demonstrating the pitfalls of a one size fits all approach.
Показать больше [+] Меньше [-]Strategy for mitigation of marine debris: Analysis of sources and composition of marine debris in northern Taiwan
2014
Kuo, Fan-Jun | Huang, Hsiang-Wen
Six sites (two sites for each of rocky shores, sandy beaches, and fishing ports) in northern Taiwan were selected to investigate the amount and density of marine debris in each of the four seasons and after spring and neap tides from 2012 to 2013. The results indicate that marine debris was higher on rocky shores than sandy beaches and fishing ports. There is no significant difference between season and tide. The dominant debris was plastic-type, followed by polystyrene. The majority of debris originated from recreational activities, followed from ocean/waterway activities. The results suggest that the following actions are needed: (1) continue and reinforce the plastic-limit policy; (2) increase the cleaning frequency at rocky shores; (3) promote marine environmental education, with a goal of debris-free coasts; (4) recycle fishing gear and to turn that gear into energy; and (5) coordinate between agencies to establish a mechanism to monitor debris.
Показать больше [+] Меньше [-]Monthly variation of trace metals in North Sea sediments. From experimental data to modeling calculations
2014
Lourino-Cabana, B. | Billon, G. | Lesven, L. | Sabbe, K. | Gillan, D.-C. | Gao, Y. | Leermakers, M. | Baeyens, W.
Seasonal variation in trace metal contamination in surface sediments was studied through high resolution profiles assessed monthly by DGT probes in muddy sediments of the North Sea. General parameters such as pH, temperature, dissolved oxygen and sulfides were also recorded to estimate their role in the speciation of trace metals. Experimental data were included in a thermodynamic equilibrium model to calculate major (geo)chemical processes at the water–sediment interface and to predict the fate of the trace metals in case of (physico-)chemical changes. Results showed lowest Fe, Co, Ni and Cd concentrations in summer, which are most probably due to the very high sulfide concentrations according to our theoretical calculations. Cu and Pb behavior were found to be less influenced by sulfides, since they are also strongly associated to organic matter. The whole set of results clearly indicated that metal speciation in these sediments is controlled by sulfides and OM contents.
Показать больше [+] Меньше [-]Uncharted sources of particle bound polycyclic aromatic hydrocarbons from South Asia: Religious/ritual burning practices
2014
Dewangan, Shippi | Pervez, Shamsh | Chakrabarty, Rajan | Zielinska, Barbara
This paper deals with the real–world emissions of particle bound polycyclic aromatic hydrocarbons (PAHs) emitted from different religious and ritual burning practices in India. The emission factors (EFs) of various PAHs were characterized over integrated stages of burning practices including pyrolysis, flaming and smoldering. Sampling was carried out in selected five different types of religious and ritual places: Hindu Temples (HT), Muslim Holy shrines (MG), Buddhist Temples (BT), Hindu Marriage Places (MP) and Cremation Centers (Hindu Funeral Pyre) (CC); where burning practices mostly include natural and synthetic biomaterials in different proportions. Seventy PAHs were analyzed and grouped in light PAHs (LPAHs=25) and heavy PAHs (HPAHs=45) according to number of benzene rings present and respective molecular weights. The average EF of total PAHs (TPAHs) from MP, MG, BT, HT and CC is estimated as 77.04±5.39, 99.09±6.02, 90.35±6.76, 22.78±1.57, and 77.15±6.16mg kg−1, respectively. Country level emission budget of particulate bound TPAHs from religious and ritual burning practices has also been evaluated to 0.47Gg yr−1; contributed ~23% of the 2.07Gg yr−1 – Indian emission budget of PAHs from unknown sources reported earlier.
Показать больше [+] Меньше [-]Volatile organic compound levels at one site in Rome urban air
2014
Fanizza, Carla | Incoronato, Federica | Baiguera, Silvia | Schiro, Roberto | Brocco, Domenico
Volatile organic compound (VOC), nitrogen dioxide (NO2) and ozone (O3) concentrations were measured at one site in Rome urban air during 2011. The seasonal mean concentrations of VOCs varied from 78μg m−3 in winter to 37μg m−3 in summer. Total aromatic concentration was reduced by 59% during summertime, alkanes of 39% and alkenes of 71%. VOC diurnal pattern exhibited a primary peak during the morning and a secondary peak in the evening hours coinciding with rush–hour traffic. The high correlation between benzene and toluene evidenced their common origin probably due to vehicular traffic. In summer isoprene diurnal profile showed both biogenic and anthropogenic origin. NO2 and O3 daily trends during summertime evidenced both photostationary state typical conditions and photochemical smog episodes. VOC and O3 trends also evidenced a reduction in VOC levels during O3 formation. Based on the Maximum Incremental Reactivity scale, the highest contributors to ozone production in Rome were propene, ethene and toluene. Comparing data found in Rome at the same site in 1992, 2007 and 2011, a decreasing trend in VOC levels was observed, suggesting the effectiveness of European Directives on air quality. In addition, our results were confirmed by similar data found in other urban areas around the world.
Показать больше [+] Меньше [-]Seagrass importance for a small-scale fishery in the tropics: The need for seascape management
2014
Torre-Castro, Maricela de la | Di Carlo, Giuseppe | Jiddawi, Narriman S.
Small-scale fisheries (SSF) in tropical seascapes (mosaics of interconnected mangroves, seagrasses and corals) are crucial for food and income. However, management is directed mostly to corals and mangroves. This research analyzes the importance of seagrasses compared to adjacent ecosystems in Chwaka Bay, Zanzibar, Tanzania. Using fish landings; the study investigated: location of fishing effort, fish production (biomass and species), and monetary benefits (aggregated value and per capita income). Seagrasses were the most visited grounds providing highest community benefits. Per capita benefits were equivalent to those from corals and mangroves. All three habitats provided income just above extreme poverty levels; however catches from seagrass appeared more stable. Seagrass are key ecosystems supporting SSF and protection and management are urgently needed. Adoption of a seascape approach considering all ecosystems underpinning SSF and the social aspects of fishing and a shift in emphasis from pure conservation to sustainable resource management would be desirable.
Показать больше [+] Меньше [-]Assessment of traffic-generated gaseous and particulate matter emissions and trends over Delhi (2000–2010)
2014
Sindhwani, Rati | Goyal, Pramila
Development and urbanization over the past decade has led to rapid increase in the population of Delhi, the metropolitan city of India. Consequently, there has been a tremendous increase in the number of vehicles, which are causing very high levels of air pollution. Vehicular emissions are becoming most predominant source of air pollution in Delhi. An annual emission inventory of road transport emissions of pollutants including carbon monoxide (CO), methane (CH4), nitrogen oxides (NOX), sulfur dioxide (SO2), volatile organic compounds (VOCs), particulate matter (PM10), lead (Pb) and hydrocarbon (HC), organic carbon (OC) and black carbon (BC) has been developed (for the period 2000–2010), for the Delhi region. Emissions have been estimated using emission factor and activity–based approach recommended by IPCC. The emissions of CO and NOX have increased nearly 77% and 29% respectively over 2000 to 2010, whereas contribution of SO2 has greatly reduced (~21%) due to phasing out of diesel driven buses and implementation of Bharat Stage–III norms to commercial vehicles. An appreciable increase in NOX emissions has been observed after 2005, which might be due to the use of CNG fuel. Emissions of PM10, OC and BC have decreased in 2001 and 2002, however these are continuously increasing after 2002 due to rapid rise in the annual rate of growth of registered vehicles in Delhi. Two wheelers (2Ws), which constitute 60% of total registered vehicles, have been found to be major contributors towards emissions of the pollutants considered in the present study.
Показать больше [+] Меньше [-]The 2013 severe haze over the Southern Hebei, China: PM2.5 composition and source apportionment
2014
Wei, Zhe | Wang, Li–Tao | Chen, Ming–Zhang | Zheng, Yan
PM2.5 samples were collected and analyzed for the first time in Handan City, which was listed in the top 4 polluted cities in China, during December 2012 to January 2013 when the record–breaking severe haze pollution happened. Positive Matrix Factorization method (PMF) was applied to understand major sources to the severe haze pollution over this city. The daily average concentration of PM2.5 was 160.1μg m–3, which was 2.1 times of the National Ambient Air Quality Standards of China (Class II, Annual Average Level) for daily average PM2.5 of 75μg m–3. SO42– was the most abundant ion (15.4%), followed by NH4+ and NO3–. They accounted for 39.5% of PM2.5. Eight factors were identified by positive matrix factorization (PMF) model. The major sources were coal combustion source (25.9%), secondary source (21.8%), industry source (16.2%), Ba, Mn and Zn source (12.7%), motor vehicle source (7.7%), road dust source (10.9%), K+, As and V source (6.3%) and fuel oil combustion source (2.5%).The mean value of extinction coefficient (Bext) was 682.1Mm–1 and the largest contributor to Bext was ammonium sulfate with the mean value of 221.0Mm–1, accounted for 32.4% of the Bext.
Показать больше [+] Меньше [-]Analysis of the spatial representativeness of rural background monitoring stations in Spain
2014
Martín, Fernando | Fileni, Lorenzo | Palomino, Inmaculada | Vivanco, Marta G. | Garrido, Juan L.
The spatial representativeness of rural background air quality stations was estimated using the spatial distribution of air pollutants computed by the combinations of the results of annual WRF–CHIMERE model simulations and data measured at stations of the Iberian Peninsula in 2008, 2009 and 2010 for NO2, SO2, O3 and PM10. The advantage of using validated models combined with measurements is that effects of the emission sources distribution and atmospheric pollutant processes are both taken into account and that the model bias and errors are corrected. This methodology provides a considerably realistic spatial view of air pollutant concentration distribution around the rural background stations. The criteria for delimiting the representativeness area are based on the assumptions that: (1) concentration does not differ by more than a certain percentage from the concentration at the station; and (2) the air quality in the station and in the representativeness area should have the same status regarding the legal standard. The results showed that there is a large variability in the size and shape of the representativeness area of rural background stations in Spain, also depending on the pollutant and the limit or target value. In addition, the interannual variability of the representativeness areas, station redundancy and network coverage have been analyzed. A high interannual variability of spatial representativeness areas was found, except for daily and hourly SO2, hourly O3 and annual NO2. Roughly 50% of rural background stations measured O3 overlap with other stations in at least 80% of their spatial representativeness area, denoting a high percentage of station redundancy. Concerning network coverage, there are zones that are not covered by stations, the worst coverage being for PM10. The proposed methodology seems to be useful for determining the spatial representativeness of air quality stations.
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