scholarly journals The River Runs Through It: the Athabasca River Delivers Mercury to Aquatic Birds Breeding Far Downstream

2018 ◽  
Author(s):  
Craig E. Hebert

AbstractThis study examined factors contributing to temporal variability (2009-2017) in total mercury (THg) concentrations in aquatic bird eggs collected in the Peace-Athabasca Delta and Lake Athabasca in northern Alberta. Factors examined included annual changes in oil sands production, bird diets, forest fires, and flow of the Athabasca River. Surface mining activities associated with Alberta’s Athabasca oil sands are centered north of Fort McMurray, Alberta, adjacent to the northward-flowing Athabasca River. Previous studies have found that oil sands industrial operations release mercury into the local (within ~50 km) environment. However, temporal trends in egg THg levels did not track trends in synthetic oil production from the oil sands. Intraspecific fluctuations in bird diet also could not explain annual variability in egg THg levels. Annual extent of forest fires in Alberta was only related to egg THg concentrations in California Gulls from Lake Athabasca; annual levels in other species showed no relationship with fire extent. The inclusion of more terrestrial foods in gull diets may have contributed to this difference. For the majority of species, annual fluctuations in maximal flow of the Athabasca River were important in influencing annual egg THg levels. Eggs collected following years of high flow had higher THg concentrations with distinct stable Hg isotope compositions. Riverine processes associated with suspended sediment were likely critical in regulating Hg availability to nesting birds. This study highlights the importance of the Athabasca River as a conduit for Hg transport to ecologically-sensitive downstream ecosystems such as the Peace-Athabasca Delta and Wood Buffalo National Park (a UNESCO World Heritage Site). Human activities that increase atmospheric Hg deposition to the Athabasca River watershed, or that enhance Hg releases to the river through erosion of Hg-bearing soils, will likely increase the availability of Hg to organisms inhabiting downstream areas.


2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Rohayah Che Amat

This research presents the value of historic urban landscape (HUL) elements in influencing the character of George Town UNESCO World Heritage Site (WHS), Penang, Malaysia. The values were perceived by the local community of different social-cultural groups that occupied the study area. The historic urban landscape elements constitute towards the protection of its townscape. The identification of the heritage elements influenced by the community interaction with their environment. This study also helps to define the character of a place, as well as reflecting its historical significance. The study adopted four techniques to gather both qualitative and quantitative data, including questionnaire survey, in-depth interview, visual survey and content analysis. In general, the local community has the capability in valuing the historic urban landscape values. The outcomes of their perceptions became the statement of the historic urban landscape values, which are expected to lead to the development of the areas. The community evaluation and perception can be expanded in implementing any development of the historic urban area by the authority.



2021 ◽  
Vol 13 (14) ◽  
pp. 8006
Author(s):  
Till Schmäing ◽  
Norbert Grotjohann

The Wadden Sea ecosystem is unique in many respects from a biological perspective. This is one reason why it is protected by national parks in Germany and by its designation as a UNESCO World Heritage Site. In biology didactics, there are only a few studies that focus on the Wadden Sea. This work investigates students’ word associations with the two stimulus words “national park” and “UNESCO World Heritage Site”. The survey was conducted among students living directly at the Wadden Sea and among students from the inland. The analysis of the identified associations (n = 8345) was carried out within the framework of a quantitative content analysis to be able to present and discuss the results on a group level. A statistically significant difference was found between the two groups. Overall, results showed that the students made subject-related associations as well as a large number of associations to both stimulus words that could be judged as non-subject-related. In some cases, a connection with the region of residence could be found, but this was not generally the case. Even students’ immediate residential proximity to the Wadden Sea is no guarantee that they have knowledge of the two considered protection terms.



2016 ◽  
Author(s):  
Dipesh Rupakheti ◽  
Bhupesh Adhikary ◽  
Puppala S. Praveen ◽  
Maheswar Rupakheti ◽  
Shichang Kang ◽  
...  

Abstract. Lumbini, in southern Nepal, is a UNESCO world heritage site of universal value as the birthplace of Buddha. Poor air quality in Lumbini and surrounding regions is a great concern for public health as well as for preservation, protection and promotion of Buddhist heritage and culture. We present here results from measurements of ambient concentrations of key air pollutants (PM, BC, CO, O3) in Lumbini, first of its kind for Lumbini, conducted during an intensive measurement period of three months (April–June 2013) in the pre-monsoon season. The measurements were carried out as a part of the international air pollution measurement campaign; SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley – Atmospheric Brown Clouds). The ranges of hourly average concentrations were: PM10: 10.5–604.0 µg m−3, PM2.5: 6.1–272.2 µg m−3; BC: 0.3–30.0 µg m−3; CO: 125.0–1430.0 ppbv; and O3: 1.0–118.1 ppbv. These levels are comparable to other very heavily polluted sites throughout South Asia. The 24-h average PM2.5 and PM10 concentrations exceeded the WHO guideline very frequently (94 % and 85 % of the sampled period, respectively), which implies significant health risks for the residents and visitors in the region. These air pollutants exhibited clear diurnal cycles with high values in the morning and evening. During the study period, the worst air pollution episodes were mainly due to agro-residue burning and regional forest fires combined with meteorological conditions conducive of pollution transport to Lumbini. Fossil fuel combustion also contributed significantly, accounting for more than half of the ambient BC concentration according to aerosol spectral light absorption coefficients obtained in Lumbini. WRF-STEM, a regional chemical transport model, was used to simulate the meteorology and the concentrations of pollutants. The model was able to reproduce the variation in the pollutant concentrations well; however, estimated values were 1.5 to 5 times lower than the observed concentrations for CO and PM10 respectively. Regionally tagged CO tracers showed the majority of CO came from the upwind region of Ganges valley. The model was also used to examine the chemical composition of the aerosol mixture, indicating that organic carbon was the main constituent of fine mode PM2.5, followed by mineral dust. Given the high pollution level, there is a clear and urgent need for setting up a network of long-term air quality monitoring stations in the greater Lumbini region.



Author(s):  
J. Aouissi ◽  
Z. L. Chabaane ◽  
S. Benabdallah ◽  
C. Cudennec

Abstract. The impact of changes in agricultural land use and practices as a controlling driver of hydrologic response and as a source of diffuse pollution, are studied in the Joumine River basin, discharging into the Ichkeul Lake, northern Tunisia, a UNESCO World Heritage site since 1979. The lake is characterized by a very specific hydrological functioning based on a seasonal alternation of water levels and salinity through its link to the Mediterranean Sea. Three Landsat images, in situ surveys and SWAT modelling were used to simulate and assess streamflows and nitrate loads under retrospective land uses.



CivilEng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 969-985
Author(s):  
Demiana Tse ◽  
João M. Pereira ◽  
Paulo B. Lourenço

Historic monuments and construction capture the knowledge of civilizations of the past and are a source of pride for people of the present. Over the centuries, these buildings have been at risk from natural and man-made causes. The Alhambra, a UNESCO World Heritage Site in Granada, Spain, is one of such places. This paper aims to evaluate the structural performance of the Torre de la Vela, a tower in the Alhambra, under blast loads. The loads were based on historical records of barrels of gunpowder and were modeled as simplified pressure profiles using existing empirical equations. The effect of impulsive loading on the material properties was accounted for using dynamic increase factors, determined experimentally by previous authors. The model was created using finite element methods (FEM) and the problem was solved using explicit dynamic analysis available in Abaqus/Explicit. Using the failure volume damage index, a blast load applied outside and inside of the building would create a low damage level, which should be treated with caution given the occurrence of localized damage. The removal of elements exceeding a given damage threshold led to more visible damage patterns than the Concrete Tension Damage option in Abaqus.



2016 ◽  
Vol 2 (1) ◽  
pp. 26 ◽  
Author(s):  
Julio Bros Williamson ◽  
Jon Stinson ◽  
Alasdair Reid ◽  
John Currie

Resumen Compuestos alternativos en el sector de la envolvente se obtienen por extrusión de estirado de secciones y perfiles de panel de enclavamiento estrechas. Estos elementos estructurales, resistentes al impacto, tienen la ventaja de una instalación más rápida y segura, y su diseño modular les hace idóneos para muchos edificios y otras aplicaciones. Un desarrollo adicional en esta área puede ser la obtención de una alternativa sostenible a los perfiles compuestos actuales. Estudios anteriores han demostrado que los compuestos fabricados a partir de materiales naturales tales como fibras y polímeros bio-derivados, ofrecen una alternativa sostenible a los polímeros y materiales compuestos tradicionales. El objetivo de este desarrollo es reemplazar el típico perfil de acero ligero. Los perfiles de acabado también se pueden utilizar para terminar tabiques de mampostería existentes, revestimiento de ejes mecánicos y de extracción y revestimiento de la columna. Los perfiles se han diseñado utilizando bio-polímeros, reforzados con fibras naturales. Se han establecido los parámetros de procesamiento y las formulaciones apropiadas de bioresina y fibras naturales. También se ha evaluado la adaptación de las técnicas de procesamiento de pultrusión existentes a las características concretas de los nuevos biomateriales y fibras naturales. Como resultado, los perfiles de pultrusión adaptados a la construcción se han desarrollado con la incorporación de nuevos materiales y biomateriales basados en resina. Abstract This paper documents an innovative partnership project between Historic Scotland, the Scottish Energy Centre at Edinburgh Napier University and Castle Rock Edinvar Housing Association in which five Category B Listed, traditional pre-1919, solid wall ‘hard-to-treat’ residential tenement properties located within Edinburgh’s historic UNESCO World Heritage site each received energy efficient upgrades to walls and windows. A variety of measures were tested, achieving significant reductions in fabric heat loss without impacting upon the character and appearance of the buildings. The project is significant in that the energy-efficient upgrades all met with strict conservation requirements on alterations to Listed Buildings and have the potential to be replicated in similar properties throughout Scotland. The project won the award for best refurbishment project at the Carbon Trust’s Low Carbon Building Awards in 2012. All of the properties featured in this study are occupied by tenants within the social-rented sector who prior to the study had indicated some thermal discomfort due to poor window conditions and high heat loss through walls causing increase fuel consumption. The occupants all remained in their homes during the refurbishment activities. 



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