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The increase in the diversity of needs arising from population growth, technological development and globalization causes more use of limited natural resources and brings with it consequences such as wear and pollution of resources. This study focused on the dam lakes on the Kızılırmak River in Türkiye, whose fisheries production rights were leased. There are İmranlı, Yamula, Bayramhacılı, Hirfanlı, Obruk, Boyabat and Derbent dam lakes on which the right to produce fishery products are leased on Kızılırmak, which is the longest river within the borders of Türkiye. Among these, the most rented region is in the Hirfanlı Dam Lake. Sustainability of fisheries in these dam lakes on Kızılırmak River is important in terms of meeting healthy protein demand and socio-economic development. Fishing, which has commercial value in these dam lakes, provides both employment and significant economic contribution to the people of the province and district where they are located. In order to benefit from this potential in a healthy way, it has been concluded that it is very important to operate these dam lakes in a balance of protection and use. However, it is necessary to increase the incentives and support of fishermen especially in these fishing regions.

The present study was conducted to assess the efficiency of solar energy in treating any potential pollution of drinking water in dam lakes caused by human activity in rural areas. The water quality parameters include temperature, pH, conductivity, total suspended solids, total nitrogen, total phosphorus, NH4-N, NO3-N, HCO3, Cl-, Na+, Mg2+, Ca2+, SAR, B, K+, SO42-, and E-coli were monitored. Samples was collected during the summer and winter (during the filling period). The results showed a rapid decrease in microbial counts upon exposure to solar radiation. More than 98% reductions were achieved after 8 hours for the bacterial communities tested under different conditions. The rate of inactivation, however, varied and was mainly affected by water turbidity and temperature during the experiments. The results indicated that turbidity affected the efficiency of water disinfection, and the efficiency improves with longer exposure duration, implying that in high turbidity and severe weather conditions, exposure time must be increased to compensate for the effects of these factors. The water in the system should be exposed to at least eight hours before leaving to the storage tanks. When scaled up, the proposed method could be a vital tool in solar water disinfection technologies, particularly in isolated and rural locations. Using solar energy to disinfect polluted water will certainly reduce the usage of chlorination and or filtration in water treatment, reducing treatment costs while also protecting the environment.

A complex of works including geomorphological deciphering, field survey, drilling, electric prospecting, and dating of deposits using the radiocarbon method and optically stimulated luminescence are used for the interpretation of the Late Quaternary evolution of the western part of the Turan–Uyuk Basin. It is established that the total thickness of the deposits of the basin reaches 190 m. The Late Quaternary evolution of the basin includes the following main stages: (1) accumulation of alluvium and active lateral migrations of the Uyuk riverbed and simultaneous sedimentation of lacustrine sequences in the basin of the Belye lakes during most of the Late Pleistocene (at least, beginning from 77–87 ka) and the first part of the Holocene (prior to 6.1–6.2 ka); the formation of floodplain massifs of the 1st and 2nd generations; the internal delta of the Uyuk River, which dams the present-day Belye lakes, started to form no later than 25–16 ka; (2) the increase in freshet activity and activation of deep and lateral erosion between 6.1–6.2 and 2.4–2.6 ka; the formation of the 3rd generation floodplain; (3) the decrease in freshet activity and the size of the paleoriverbeds, the predominance of lateral migrations of the riverbed, and accumulation of alluvium in the last 2.4–2.6 ka; the formation of the 4th generation floodplain. The last stage is characterized by a shorter period of strong activation of cryogenesis. Permafrost began to form no earlier than 2.8 ka, and cryogenesis was mostly active at 1.35–1.10 ka. The Late Pleistocene stage of accumulation was preceded by a strong downcutting of the Uyuk valley, probably caused by the activation of tectonic movements. The chronological boundaries of this downcutting are determined only approximately: between 360–380 and 77–87 ka. The presence of a large dam lake, which occupied the central and western part of the basin and was suggested by some researchers, is not confirmed. [ABSTRACT FROM AUTHOR]

Natural ecosystems represented by the surface waters, which have developed during a long period prior to the human intervention, are replaced, modified and fragmented in a short period of time through dams, some linkage systems between the rivers through the old riverbeds and newly built channels and through the arrangement of the banks. In the water catchment area of the Danube, the effects of the major human intervention over the geographical area, especially over the large tributary rivers of this large stream, such as Argeș river, and also on most of the smaller running waters are harder and harder to monitor, to anticipate and to correct. The natural flowing regime of some tributary waters of the Danube has been considerably changed; thus, significant changes happen to the hydrological, physical-chemical and biological features of the waters through the emergence of some lake ecosystems, with a fragile balance. Important changes emerge at the level of some physical-chemical and biological qualitative indicators, such as: the turbidity, the dissolved oxygen content, the oxidation and mineralization of the organic material, malfunctions of some the selfcleaning processes, the accumulation of biogenic substances, eutrophication, the accumulation of mineral substances in the bed areas, the replacement of the river biocoenosis with a lake biocoenosis, the development of plankton, especially of the productive forms, the malfunction of the structure and dynamics of the fish fauna etc. The impact of human activity has a bad influence, in most of the cases, on the quality of the water in the dam lakes. The sustainable management of the water resources of these lakes, through the nearby urban and rural communities requires a knowledge of the environmental problems that are generated by the human impact and their removal or minimization.

The aim of this study was to investigate the integral indicator for developmental stability, the fluctuating asymmetry (FA), in the marsh frog Pelophylax ridibundus populations that inhabit biotopes of different types (running rivers and still, dam lakes), when exposed to different types of anthropogenic pollution (domestic sewage pollution and heavy metal pollution) in south Bulgaria. A total of 920 P. ridibundus individuals were used for FA analyses over three years (2009-2011). Fluctuating asymmetry was defined by 10 morphological traits, using the index frequency of asymmetric manifestation of an individual (FAMI). In closed water basins, regardless of the nature of toxicants, the FA values in P. ridibundus populations were statistically lower than those in river populations. The FA values were constantly the highest under conditions of sustained anthropogenic pollution, with high concentrations of toxicants in rivers with domestic sewage pollution and heavy-metal pollution. The results provide better opportunities to use FA in P. ridibundus populations for bioindication and biomonitoring, and for parallel and independent analyses of the physicochemical assessment of the environmental condition.

Edirne Province is located in the Thrace part of Marmara Region and intensive agricultural activities are conducted around the city, because of contained rich soil and much freshwater resources. In this study, water quality of Sultanköy (İpsala District), Altınyazı (Uzunköprü District), Süloğlu (Süloğlu District), and Kadıköy (Keşan District) Dam Lakes, which were constructed by DSİ (State Water Works) in order to provide irrigation water (Sultanköy and Altınyazı) and drinking water (Süloğlu and Kadıköy) to the places where they are located on, were investigated. For this purpose, water samples were collected from the output locations of all the reservoirs in spring season of 2016. Total of 13 physiochemical water quality parameters (pH, conductivity, TDS, salinity, turbidity, nitrate, nitrite, phosphate, sulfate, chemical oxygen demand, total carbon, total inorganic carbon and total organic carbon) were measured. Also Cluster Analysis (CA) was applied to detected data in order to classify the reservoirs in terms of contamination levels. According to detected data, pollution levels of the investigated dam lakes as follows; Sultanköy > Altınyazı > Kadıköy > Süloğlu in general. According to the results of CA, 3 statistically significant clusters were formed, which were corresponded to Süloğlu Dam Lake (Cluster 1); Kadıköy and Altınyazı Dam Lakes (Cluster 2); Sultanköy Dam Lake (Cluster 3). [ABSTRACT FROM AUTHOR]

A thorough investigation of the impact of rainbow trout ( Oncorhynchus mykiss) cultivation on surface water quality in the area known as Bereket HES IV Dam Lake was conducted. Water samples were collected from October 2009 to June 2010 from four stations in the Dam Lake and analyzed for water temperature, pH, dissolved oxygen, electrical conductivity, nitrite nitrogen, nitrate nitrogen, and orthophosphate. Surface water quality was then evaluated based on the comparison of samples collected from three stations located near fish cages to those collected from a reference station outside the cultivation area as well as by the comparison with standards specified in the Water Pollution Registration Act. According to the Water Pollution Registration Act, the surface water quality of the Dam Lake was class I. Additionally, there were no significant differences in water quality within the Dam Lake among any of the sampling stations, including the reference station. Overall, these findings indicate that cage cultivation of rainbow trout may have a negative impact on the entire Dam Lake. [ABSTRACT FROM AUTHOR]

Gökçekaya Dam is one of the dams located on the Sakarya River (Eskişehir) in Turkey and is approximately 38 years old. No study regarding to the water quality of the dam lake has been hitherto made. This study aimed at determining the seasonal variations with physical, chemical, and biological parameters of the water quality of the dam lake. Depth-wise water samples were taken from five selected stations, in seasonal periods during 2005-2008, and anlayzed. The quality of water was classified in accordance with the results and taking into consideration many parameters. At the same time, number and type diversities of dissolved heavy metals and algae population were analyzed. Using principal component analysis (PCA) and classification analysis (CA) methods, differences between these parameters and samples from stations have been determined . The analysis showed that Gökçekaya dam lake, formerly an oligotrophic lake, has become a mesotrophic lake. And according to the results thereof the Lake has mezotrophic characteristics due to the sudden changes (including household waste water inflow and opening the Sarıyar dam lake shutters) in certain periods and in some stations. Hierarchical clustering analysis, revealed no significant difference between the measured parameters. And according to the Water Pollution Control Regulations in Turkey (WPCR) Gökçekaya dam lake is in the first class quality in terms of anions, cations, heavy metals, temperature, and pH values. However, the is of first class quality presence of nitrite reduces the water quality in the lake and causes this lake to be classified in the fourth class quality. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the response of a multimarker approach in common carp Cyprinus carpio sampled from three Tunisian dam lakes selected according to different environmental and ecological characteristics. Glutathione- S-transferase (GST) activity was analyzed in carp liver and used as a phase II detoxification enzyme, hepatic metallothionein content (MTs) was used as a metallic stress indicator, and cholinesterase activities were analyzed in muscle and brain and used as neurotoxicity biomarker. Micronucleus frequency test (MN) as a genotoxicity marker. GST and MT levels showed an increase in fish from the Bir Mcherga site and a decrease in Sidi Saâd site with respect to fish from Nebhana site. Results showed a strong inhibition of cholinesterase activities in fish from Bir Mcherga and Sidi Saâd sites compared to Nebhana site. Relatively high level of MN is reported specially in fish blood from the Bir Mcherga site. [ABSTRACT FROM AUTHOR]

The evaluation of trace elements (TEs) in sediments of dam lakes is crucial for maintaining ecosystem health. Therefore, it is very important to determine their concentrations, pollution status, sources, controlling factors and ecological risks in these ecosystems. Here, for the first time, we analyzed 14 TEs (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sb, Hg and Pb) and sediment properties (organic matter (OM) and pH) in sediments from four dam lakes (Erfelek, Derbent, Suat Uğurlu and Saraydüzü) in the Black Sea Region of Turkey, which are used for different purposes and located on the different rivers or streams with different pollution levels. The results indicated that Al, V, Mn, Fe, Cu, Zn, As, Pb and Sb concentrations were lower in the Erfelek Dam Lake which has been used for drinking water supply, indicating that it is more protected than other dam lakes. However, Al, V, Mn, Fe, Co, Cu and Sb concentrations were higher in the Suat Uğurlu Dam Lake on the Yeşilırmak River which is moderately polluted. According to sediment contamination indices, there was low contamination in the sediments of all dam lakes. Similarly, the assessment of ecological risk posed by TEs indicated low eclogical risk in the dam lakes. Sediment OM and pH were found to be important control factors affecting the distribution of TEs in the dam lakes sediments. Correlation and factor analyses suggested that all TEs in the sediments of dam lakes mainly originated from geogenic sources. • The contens of 14 TEs in the sediments of four dam lakes were compared. • Ecological risk indices and SQGs were used to assess ecological risks of TEs. • Effects of OM and pH on the accumulation of TEs in sediments were investigated. • Factor and correlation analyses were conducted for source identification of TEs. [ABSTRACT FROM AUTHOR]