Sonila Duka

Bio: Sonila Duka is an academic researcher from University of Tirana. The author has contributed to research in topics: Water quality & Chromium. The author has an hindex of 3, co-authored 10 publications receiving 18 citations.

Biomonitoring of water quality of the Osumi, Devolli, and Shkumbini rivers through benthic macroinvertebrates and chemical parameters

Abstract: Environmental monitoring of river water quality in Albania, using biological and chemical parameters, is a fast and effective way to assess the quality of water bodies.The aim of this study was to investigate Ephemeroptera, Plecoptera and Trichoptera (EPT), Biotic index-Richness using macroinvertebrates to assess the water quality, with special reference to nutrient (phosphorus and nitrogen) levels in the Devolli, Shkumbini and Osumi rivers. Our objective was to investigate the relationships between the measures of benthic macroinvertebrate communities and nutrient concentrations to assess water quality. The rivers' benthic macroinvertebrates were collected during different seasons in 2012. The biological and chemical parameters used in the current study identified them as quick indicators of water quality assessment. The total number of macroinvertebrate individuals (n = 15,006) (Osumi river: n = 5,546 organisms; Devolli river: n = 3,469 organisms; and Shkumbini river: n = 5,991 organisms), together with the EPT group (Ephemeroptera, Plecoptera, and Trichoptera), showed that the water quality at the river stations during the above-mentioned period belonged to Classes II and III (fair water quality and good water quality, respectively). The classification of the water quality was also based on the nitrogen and total phosphorus contents. The pollution tolerance levels of macroinvertebrate taxa varied from the non-tolerating forms encountered in environments with low pollution levels to the tolerating forms that are typical of environments with considerable pollution levels.

Limnological study on a newly built drinking water reservoir near Tirana, Albania

Abstract: Bovilla Lake is a reservoir constructed 12 years ago for supplying the city of Tirana (Albania) mainly with drinking water. It has a surface area of 4.6 km2, a maximum depth of originally 60 m and is monomictic with a stratification period from early spring to end of October. The lake is oligotrophic with low nutrient concentrations (e.g. SRP in spring about 8 μg L − 1) and minor oxygen depletion in the hypolimnion during thermal stagnation. The lake is highly turbid due to severe particle import by several rivers during rain periods. This led to a massive deposition of sediments, lifting the maximum depth to 45 m in 2008. Furthermore, the photic zone reached hardly more than 10 m. Algal species diversity is high; however, diatoms from the genus Cyclotella dominate most of the year both in numbers and biomass. Our study describes for the first time the hydrography and limnology of the Bovilla Reservoir.

The Spatial and Temporal Variability of Limnological Properties of Bovilla Reservoir (Albania)

Abstract: A limnological survey of a man-made reservoir in the central part of Albania was conducted from May 2006 to May 2008. This water body is being constructed 15 years ago for water supply of the Tirana, capital city of Albania. The physical and chemical quality of water in this reservoir was determined and compared against universally accepted water quality standards. Water quality parameters relevant to the study area are discussed considering the ecosystem function and interrelationship among physical and chemical parameters with the biological ones. The water quality of traditional and modern reservoir was not significantly different except for a bed odour that occurs throughout of the summer. Due to the reservoirs life the eutrophication in the nowadays is not a major problem in the reservoir, but due to an intensive sedimentation rate it is predicted that will seriously affect the water body in the near future. Management strategies to improve the water use efficiency with particular reference to eutrophication are proposed. On the other hand it is recommended that an integrated approach following the IRBM criteria will be the best way of management and administration.

Water Quality from Microbiological Point of View of Vjosa River, Albania

Abstract: An increasing impact of human activities in environment is noticed during the last decades. The socialeconomic development has been accompanied by considerable changes in aquatic and terrestrial ecosystems. One of our duties is to monitor continuously human impact in environment and for this reason we decided to monitor water quality of Vjosa River, as one of most important rivers in south of Albania, based on microbiological indicators during 2011. Vjosa is a transboundary river, shared between Greece and Albania, whose spring is in Pindi Mountains. Its total length is about 272 kilometres, of which the first 80 kilometres are in Greece, and the remaining 192 kilometres are in Albania, where it passes through many urban areas and a relatively high human impact is expected. Samples are collected almost every month from March 2011 in six stations along the river. MPN index is used for evaluation of total coliform bacteria in water, while the number of heterotrophic bacteria is determined by counting colonies on plates with PCA, cultivated with 0.1 ml sample after a serries dilutions. Environmental parameters like pH, temperature, turbidity, ammonia, phosphate, nitrite and dissolved oxygen are estimated using standard methods. According to preliminary results, as it was expected, there is a high load of feacal coliform bacteria and heterotrophs in sample stations near urban areas. A seasonal change is observed in bacterial parameters. The human impact in the quality of water of Vjosa river is more than evident.

Stochastic Modelling of Reservoir Sedimentation in a Semi-Arid Watershed

Abstract: Sedimentation in large reservoirs is a major concern in semi-arid regions characterized by severe seasonal water scarcity. As a contribution to improved sediment management, this study analyses the real case of the reservoir of Sidi Yacoub in the north of Algeria. First, a dynamic model of the reservoir was set up and used to estimate past water and sediment inflows (period 1990–2010) based on data recorded by the dam operator and measurements at a gauging station located downstream of the reservoir. Second, in a stochastic framework using the statistical characteristics of inflow and outflow discharges, a projection of future sedimentation was performed until 2030, assuming stationarity of the statistical distributions. Third, the model was used to investigate the influence of possible climate change and to quantify the positive effects of soil conservation measures upstream.

River health assessment of the Yellow River source region, Qinghai-Tibetan Plateau, China, based on tolerance values of macroinvertebrates

Abstract: For decades, the river health of the Yellow River source region (YRSR) on the Qinghai-Tibetan Plateau has been a focal issue owing to its unique geographic location and ecological functions. This study investigated the ecological status of the headwater streams, the main stem, and the tributaries of the Yellow River in the YRSR using the tolerance values of macroinvertebrates and those related to biotic indices. The macroinvertebrate assemblages of the headwater streams were characterized by lower biodiversity than the tributaries downstream, based on comparisons of taxonomical composition, functional feeding group composition, and the pollution-tolerant capacity of taxa. The headwater streams had a lower ratio (16%) of pollution-sensitive macroinvertebrate taxa than that of the tributaries downstream (30%). The biotic indices (family- and genus-level biotic indices) indicated that the ecological health of the headwater streams was comparably poorer than that of the downstream tributaries. The combined effect of vulnerable natural conditions and increasing human disturbance is likely the main cause of eco-environmental degradation in the Yellow River headwater streams.

Eutrophication in the newly built Laohutan Reservoir during the initial impoundment period: the role of nutrient loading

Abstract: The purpose of this study was to elucidate the role of nutrient loading played in the eutrophication of newly built reservoirs Taking the Laohutan Reservoir as an example, field monitoring and laboratory experiments were conducted before and after the reservoir impoundment According to the results, the Laohutan Reservoir was eutrophicated 4 months after its impoundment, since nutrient loading played an important role Riverine inputs were found to be the major source of nutrients, with the contribution of greater than 72 % Nutrients from soil were also influential during the first 20 days Its release was gradually weakened by the routine operations of the reservoir The release patterns of nutrients from the four main land-use types of soil (forest, bamboo groves, paddy and construction sites) were similar, but their influence to the reservoir water quality varied dramatically And the atmosphere was also an important source of nutrients, especially nitrogen Meanwhile, by a comparison, the Laohutan Reservoir to an older one located nearby, the newer with relatively lower trophic levels underwent a cyanobacteria bloom, while there was none in the older It verified that new reservoirs were more prone to eutrophication than the older, and high nutrient loading is a necessary but not sufficient condition for eutrophication The fragility of the new reservoir’s ecosystem accelerated water environment deterioration, and resulted in the eutrophication and cyanobacteria bloom during the initial impoundment period

Spatial Profiling and Assessing Dominance of Sources to Water Phosphorus Burden in a Shallow Lake

Abstract: Efficacy of phosphorus (P) mitigation strategies in lake basins could not be quantitatively evaluated due to a lack of assessment frameworks, confounding preferential management. The promiscuity in contributions of P sources to burden is a major cause. This study aimed to spatially profile water P burden with special emphasis on assessing dominance of P sources in a lake system. Exploratory data analysis with multivariate statistical techniques was applied to interpret raw data matrix of 21 variables employed in water and sediment samples collected from Baiyangdian Lake, the largest freshwater shallow lake in North China. Simple trend surface analysis was performed to estimate P distribution similarities. Multivariate exploratory analysis was conducted on variables and sites to accomplish pattern recognition and magnitude identification of sources. Linear regression model was applied to quantitatively determine importance of P regulators. Results revealed that P fractionation in sediments reflected the dominance of P sources and played a pivotal role in discriminating water P burden. Intensive P enrichment was highly associated with nitrogen levels and conductivity as response of exogenous input. Sedimentary sand fraction needed more concern due to its high risks of potential sink and preferential release. Metallic oxide bound P along with organic P served as main sediment contributions. Pertinent separate strategies were suggested to be implemented sub-regionally in mitigating effects of P downstream. The proposed framework enabled assessment on source-related P burden to evaluate profits of P reduction management options and provided an alternative framework of focal point determination for local government agencies.