1,721,006 research outputs found
Determination of sources, pollution status and health risks of dissolved metals in Tohma Stream (Malatya)
No full textLisansüstü Eğitim Enstitüsü, Su Ürünleri Ana Bilim DalıBu tez çalışması, Karakaya Baraj Gölü'nü besleyen akarsular içerisinde önemli bir su potansiyeline sahip olan Tohma Çayı'nda araştırmanın amacına uygun olarak belirlenmiş 13 istasyondan mevsimsel olarak toplanan su örneklerinde 10 metalin (As, Cd, Cr, Co, Cu, Fe, Mn, Ni Pb ve Zn) düzeylerini, mekânsal ve mevsimsel değişimlerini ve potansiyel kaynaklarını tespit etmek ve elde edilen verileri insan sağlığı açısından değerlendirmek için yapılmıştır. Tohma Çayı'na ait su örneklerinde kaydedilen metallerin mekânsal dağılımları incelendiğinde, As, Cu ve Pb hariç diğer metallerin düzeylerinin 13 örnekleme istasyonu arasında istatiksel olarak önemli değişimler gösterdiği belirlenmiştir (P <0,05). Çözünmüş metallerin mevsimsel değişimleri incelendiğinde, sadece As ve Cu düzeylerinin istatiksel olarak önemli mevsimsel değişimler gösterdiği belirlenmiştir (P <0,05). En yüksek ortalama As ve Cu düzeyleri ilkbahar mevsiminde kaydedilmiştir. Bu durum, ilkbahar mevsimindeki yağışların, yüzeysel akışla bu elementleri akarsuya taşımasından muhtemelen kaynaklanmıştır. Tohma Çayı'ndan alınan su örneklerinin ortalama metal konsantrasyonlarının, içme suyu kalite kriterleri ile sucul yaşamın korunması için tatlı su kalite kriterleri tarafından izin verilen maksimum değerleri geçmediği tespit edilmiştir. Ayrıca metal indeksleri (HEI ve HPI) sonuçlarına göre su örneklerinde önemli bir kirlilik belirlenmemiştir. Karsinojenik ve kanser-dışı risk değerlendirme sonuçları, Tohma Çayı suyundaki metallerin insanlar üzerinde bir sağlık problemi oluşturmayacağını göstermiştir. Faktör, korelasyon ve kümeleme analizlerinin sonuçlarına göre, akarsudaki Cr, Ni, Co ve Mn düzeyleri üzerinde insan aktivitelerinin etkili olduğu belirlenirken diğer metallerin düzeyleri üzerinde hem insan aktivitelerinin hem de doğal kaynakların etkili olduğu tespit edilmiştir. ANAHTAR KELİMELER: Tohma Çayı, metaller, su kalitesi, kaynak tanımlama, sağlık risk değerlendirmesiThis thesis study was carried out to determine the levels, spatial and seasonal changes, potential sources and human health risks of 10 metals (As, Cd, Cr, Co, Cu, Fe, Mn, Ni, Pb and Zn) in water samples collected seasonally from 13 stations in Tohma Stream, which has a significant water potential among the streams feeding the Karakaya Dam Lake. When the spatial distributions of metals recorded in water samples of Tohma Stream were examined, it was determined that the levels of metals except As, Cu and Pb showed statistically significant changes among the 13 sampling stations (P <0.05). When seasonal changes in dissolved metals were examined, it was determined that only As and Cu levels showed statistically significant seasonal changes (P <0.05). The highest average As and Cu levels were recorded in spring. This situation is probably due to the fact that spring rainfall carries these elements to the stream via surface runoff. It was determined that the average metal concentrations of water samples taken from Tohma Stream did not exceed the maximum values allowed by drinking water quality criteria and fresh water quality criteria for the protection of aquatic life. In addition, according to the results of metal indexes (HEI and HPI), no significant contamination was detected in the water samples. Carcinogenic and non-cancer risk assessment results have shown that metals in Tohma Stream water will not pose a health problem to humans. According to the results of factor, correlation and clustering analyses, it was determined that human activities were effective on the levels of Cr, Ni, Co and Mn in the stream, while both human activities and natural resources were effective on the levels of other metals. KEYWORDS: Tohma Stream, metals, water quality, spatial and seasonal changes, source identification, health risk assessmen
Determination of sources, pollution status and health risks of dissolved metals in Tohma Stream (Malatya)
No full textLisansüstü Eğitim Enstitüsü, Su Ürünleri Ana Bilim DalıBu tez çalışması, Karakaya Baraj Gölü'nü besleyen akarsular içerisinde önemli bir su potansiyeline sahip olan Tohma Çayı'nda araştırmanın amacına uygun olarak belirlenmiş 13 istasyondan mevsimsel olarak toplanan su örneklerinde 10 metalin (As, Cd, Cr, Co, Cu, Fe, Mn, Ni Pb ve Zn) düzeylerini, mekânsal ve mevsimsel değişimlerini ve potansiyel kaynaklarını tespit etmek ve elde edilen verileri insan sağlığı açısından değerlendirmek için yapılmıştır. Tohma Çayı'na ait su örneklerinde kaydedilen metallerin mekânsal dağılımları incelendiğinde, As, Cu ve Pb hariç diğer metallerin düzeylerinin 13 örnekleme istasyonu arasında istatiksel olarak önemli değişimler gösterdiği belirlenmiştir (P <0,05). Çözünmüş metallerin mevsimsel değişimleri incelendiğinde, sadece As ve Cu düzeylerinin istatiksel olarak önemli mevsimsel değişimler gösterdiği belirlenmiştir (P <0,05). En yüksek ortalama As ve Cu düzeyleri ilkbahar mevsiminde kaydedilmiştir. Bu durum, ilkbahar mevsimindeki yağışların, yüzeysel akışla bu elementleri akarsuya taşımasından muhtemelen kaynaklanmıştır. Tohma Çayı'ndan alınan su örneklerinin ortalama metal konsantrasyonlarının, içme suyu kalite kriterleri ile sucul yaşamın korunması için tatlı su kalite kriterleri tarafından izin verilen maksimum değerleri geçmediği tespit edilmiştir. Ayrıca metal indeksleri (HEI ve HPI) sonuçlarına göre su örneklerinde önemli bir kirlilik belirlenmemiştir. Karsinojenik ve kanser-dışı risk değerlendirme sonuçları, Tohma Çayı suyundaki metallerin insanlar üzerinde bir sağlık problemi oluşturmayacağını göstermiştir. Faktör, korelasyon ve kümeleme analizlerinin sonuçlarına göre, akarsudaki Cr, Ni, Co ve Mn düzeyleri üzerinde insan aktivitelerinin etkili olduğu belirlenirken diğer metallerin düzeyleri üzerinde hem insan aktivitelerinin hem de doğal kaynakların etkili olduğu tespit edilmiştir. ANAHTAR KELİMELER: Tohma Çayı, metaller, su kalitesi, kaynak tanımlama, sağlık risk değerlendirmesiThis thesis study was carried out to determine the levels, spatial and seasonal changes, potential sources and human health risks of 10 metals (As, Cd, Cr, Co, Cu, Fe, Mn, Ni, Pb and Zn) in water samples collected seasonally from 13 stations in Tohma Stream, which has a significant water potential among the streams feeding the Karakaya Dam Lake. When the spatial distributions of metals recorded in water samples of Tohma Stream were examined, it was determined that the levels of metals except As, Cu and Pb showed statistically significant changes among the 13 sampling stations (P <0.05). When seasonal changes in dissolved metals were examined, it was determined that only As and Cu levels showed statistically significant seasonal changes (P <0.05). The highest average As and Cu levels were recorded in spring. This situation is probably due to the fact that spring rainfall carries these elements to the stream via surface runoff. It was determined that the average metal concentrations of water samples taken from Tohma Stream did not exceed the maximum values allowed by drinking water quality criteria and fresh water quality criteria for the protection of aquatic life. In addition, according to the results of metal indexes (HEI and HPI), no significant contamination was detected in the water samples. Carcinogenic and non-cancer risk assessment results have shown that metals in Tohma Stream water will not pose a health problem to humans. According to the results of factor, correlation and clustering analyses, it was determined that human activities were effective on the levels of Cr, Ni, Co and Mn in the stream, while both human activities and natural resources were effective on the levels of other metals. KEYWORDS: Tohma Stream, metals, water quality, spatial and seasonal changes, source identification, health risk assessmen
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Environmental, ecological and health risks of trace metals in sediments of a large reservoir on the Euphrates River (Turkey)
No full textThe contents of trace metals (Cd, As, Pb, Cr, Cu, Zn, Ni, Co, Mn and Fe) in sediment samples from eleven sampling sites in The Keban Dam Reservoir, which is Turkey's second biggest reservoir, were examined to evaluate spatial distribution, possible sources, contamination status and environmental, ecological and health risks of these metals. The results indicated that enrichment factor, geoaccumulation index and contamination factor values were higher at sampling sites receiving industrial and domestic wastewater discharges. Only Cr and Ni concentrations exceeded their corresponding probable effect concentrations in 47.7% and 93.2% of the samples. Ecological risk factor and ecological risk index values at all sites were <40 and <150, respectively, indicating low ecological risk in the reservoir. Cluster, correlation and factor analyses suggested that Cr and Ni originated from mixed sources of lithogenic and anthropogenic origins, while other metals mainly originated from natural sources. For children and adults, hazard quotient value of each metal from ingestion and dermal contact pathways did not exceed 1. Carcinogenic risk (CR) values of arsenic from these two exposure pathways and total CR value were within the range of acceptable risks. Thus, in terms of recreational uses, the reservoir is considered to be safe for human health
Impact of paddy fields on water quality of Gala Lake (Turkey): An important migratory bird stopover habitat
No full textGala Lake is an internationally important lake due to its location on one of the world's most important bird migration routes. For this reason, water quality of the lake is of great concern. However, the lake surrounded by paddy fields may face eutrophication and toxic metal contamination due to excessive use of fertilizers and pesticides. In this study, impact of paddy fields on water quality of the Gala Lake was investigated. The concentrations of metal(loid)s and physico-chemical parameters in surface water samples taken from the lake were measured and compared with water quality guidelines. Also, human health risks and contamination status of metal(loid)s were assessed. The mean NO2, SRP and BOD concentrations in the lake exceeded the permissible levels for both salmonid and cyprinid waters. The mean BOD value indicated contaminated water quality in the lake, while mean COD and SRP values indicated lightly contaminated water quality. The mean As, Cr and Pb values in the winter exceeded the drinking water limits set by WHO and EC, while the mean Cr and Zn values exceeded the limit values for the protection of freshwater aquatic organisms set by USEPA. Similarly, heavy metal pollution index and the degree of contamination values in the winter indicated that the lake water is moderately polluted. Health risk assessment results revealed that As and Cr in the lake water via ingestion exposure pathway may pose both non-carcinogenic and carcinogenic health risks to the residents. The results of this study indicated that paddy fields are a major source of nutrients, organic matter and toxic metal(loid)s to the Gala Lake. To improve the water quality of the lake, we suggest that excessive use of fertilizers and pesticides should be controlled to reduce metal(loid) and nutrient loads from the paddy fields
Arsenic and trace metals in a large reservoir: Seasonal and spatial variations, source identification and risk assessment for both residential and recreational users
No full textThe Keban Dam Reservoir in Turkey is an internationally important reservoir, because it is located on the Euphrates River, which is an important transboundary river. Water samples were seasonally collected from 11 sampling sites on the reservoir between autumn 2014 and summer 2015. Spatial and seasonal variations, possible sources and health risks of dissolved trace metals (TMs) were investigated. Among ten TMs, only Cr and Mn showed significant spatial variations, while Cr, Mn and Pb did not show significant seasonal variations. The average concentrations of TMs except As and Cd indicated a decreasing trend from autumn to summer. Also, minimum total metal concentration was recorded in summer due to raised water level of the reservoir. Maximum concentrations of all TMs were lower than the drinking water guideline values set by EC (European Community), WHO and USEPA. Principle component analysis/factor analysis and correlation analysis demonstrated that all TMs originate from natural sources. Non-carcinogenic and carcinogenic risks through ingestion and dermal contact exposure pathways were estimated for both residential and recreational receptors exposed to TMs in reservoir water. Hazard quotient, hazard index (HI) and total HI values were lower than 1. Also, carcinogenic risk (CR) values of As and Cr for each exposure route and total CR values were within the acceptable range of 10(-4) and 10(-6). Thus, the Keban Dam Reservoir is safe for human health in terms of residential and recreational uses. (C) 2019 Elsevier Ltd. All rights reserved
Spatio-temporal changes in surface water quality and sediment phosphorus content of a large reservoir in Turkey
No full textThe Keban Dam Reservoir, located on the Euphrates River, is the second largest reservoir of Turkey. Water quality of this reservoir is of great importance because it is widely used for recreation, aquaculture production, fishing, and irrigation. In this study, discriminant analysis, principal component analysis (PCA), factor analysis (FA) and cluster analysis (CA) were conducted to evaluate the seasonal and spatial variations in surface water quality of the reservoir. Also, total phosphorus (TP) content in sediments, water type and trophic status of the reservoir were determined. For this, 19 water quality variables and TP in sediments were monitored seasonally at 11 sampling stations on the reservoir during one year. Hierarchical CA classified 11 stations into three groups, i.e., upstream (moderate polluted), midstream (low polluted) and downstream (clean) regions. PCA/FA allowed to group the variables responsible for variations in water quality, which are mainly related to mineral dissolution (natural), organic matter and nutrients (anthropogenic), and physical parameters (natural). Discriminant analysis (DA) gave better results for both data reduction and spatio-temporal analysis. Stepwise temporal DA identified eight variables: water temperature (WT), chemical oxygen demand (COD), nitrate nitrogen (NO3–N), soluble reactive phosphorus (SRP), chlorophyll-a (Chl-a), potassium (K+), magnesium (Mg2+), and calcium (Ca2+), which are the most significant variables responsible for temporal variations in water quality of the reservoir, while stepwise spatial DA identified three variables: K+, chloride (Cl?), and sulphate (SO4?2), which are the most significant variables responsible for spatial variations. According to Ontario sediment-quality guidelines, sediments of the reservoir can be considered as unpolluted in terms of mean TP content. The water type of the reservoir was calcium-bicarbonate. According to trophic state index values based on TP and Chl-a, upstream region (moderate polluted) of the reservoir was in the eutrophic status, whereas other regions were in the mesotrophic status
Impacts of cage fish farms in a large reservoir on water and sediment chemistry
No full textThe Keban Reservoir, which is the second man-made waterbody in Turkey, has the biggest rainbow trout production in the country. In this study, the impacts of rainbow trout farms on water and sediment chemistry were investigated. Water and sediment samples were taken at distances of 0, 10, 25, 50 and 100?m from the edge of the cages at the three fish farms, and at the respective reference stations. Samples were also taken at 0?m stations and reference stations in the late August when there were no fish in the cages. Physico-chemical variables and trace metals were analysed in all samples. Due to likely high dilution rates and recycling processes in the water column of the reservoir, little changes in the water quality parameters associated with wastes of the fish farms were noticed. When compared with those in the sediment samples at the stations near the edge of cages, the lower concentrations of total phosphorus (TP), total nitrogen (TN), organic matter (OM), total carbon (TC), sulfide (S2?), arsenic (As), cobalt (Co), copper (Cu), manganese (Mn) and zinc (Zn), and higher values of redox potential (Eh) were found at the reference stations. According to organic enrichment classification based on S2? and Eh values, sediments of the three fish farms in the period when there were fish in the cages fell into the oxic category, whereas sediments in the August (no fish farming activity) fell into the normal category. Also, it was found in the August that most of sediment quality parameters at the 0?m stations had close values to those at the reference stations. These results revealed that a three-month period when there were no fish in the cages allows for sediments to return to reference station conditions
Use of water quality index and multivariate statistical methods for the evaluation of water quality of a stream affected by multiple stressors: A case study
No full textTherefore, water quality of the stream is of great importance. In this study, multivariate statistical techniques (MSTs) and water quality index (WQI) were applied to assess water quality of the stream affected by multiple stressors such as untreated domestic sewage, effluents from fish farms, agricultural runoff and streambank erosion. For this, 16 water quality parameters at five sites along the stream were monitored monthly during one year. Most of parameters showed significant spatial variations, indicating the influence of anthropogenic activities. All parameters except TN (total nitrogen) showed significant seasonal differences due to high seasonality in WT (water temperature) and water flow. The spatial variations in the WQI were significant (p < 0.05) and the mean WQI values ranged from 87.6 to 95.3, indicating “good” to “excellent” water quality in the stream. Cluster analysis classified five sites into three groups, that is, clean region, low polluted region and very clean region. Stepwise temporal discriminant analysis (DA) identified that pH, WT, Cl?, SO42?, COD (chemical oxygen demand), TSS (total suspended solids) and Ca2+ are the parameters responsible for variations between seasons, and stepwise spatial DA identified that DO (dissolved oxygen), EC (electrical conductivity), NH4–N, TN (total nitrogen) and TSS are the parameters responsible for variations between the regions. Principal component analysis/factor analysis revealed that the parameters responsible for water quality variations were mainly associated with suspended solids (both natural and anthropogenic), soluble salts (natural) and nutrients and organic matter (anthropogenic)
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