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Öğe Accumulation of trace elements in muscle, gill and liver of fish species (Capoeta umbla and Luciobarbus mystaceus) in the Tigris River (Turkey), and health risk assessment(Elsevier, 2020) Varol, Memet; Kaçar, Emel; Karadede Akın, HülyaTwo fish species (Capoeta umbla and Luciobarbus mystaceus) were collected from the Tigris River (Turkey), and tissues (gill, muscle and liver) of fish samples were analyzed for Cd, As, Mn, Cr, Cu, Co and Ni using the inductively coupled plasma-tandem mass spectrometry. Significant differences were present between fish species in regard to trace element (TE) concentrations in muscle for Mn, in liver for Cu, Cd and Mn, and in gill for As, Co, Cu and Cd (p < 0.05). Liver had the highest total TE concentration, followed by gill and muscle. Significant negative correlations were recorded between fish size (length and weight) and TE concentrations in the tissues. Both fish species showed no gender differences in TE accumulation in muscle, gill and liver (p > 0.05). The estimated daily intakes for all TEs were much lower than the tolerable daily intakes. The target hazard quotient (THQ) and total THQ values of all TEs did not exceed 1, which means that non-carcinogenic health effects are not expected for the consumers. Arsenic carcinogenic risk values were within acceptable range. Mean Cd concentrations in muscle tissue of both fish species exceeded the maximum permissible limit set by the European Commission Regulation, while mean concentrations of As, Cr and Cu were below the legislated limits.Öğe Arsenic and trace metal concentrations in different vegetable types and assessment of health risks from their consumption(Elsevier, 2022) Varol, Memet; Gündüz, Kazım; Sünbül, Muhammet Raşit; Aytop, HalilThe levels of 12 trace metal (loid)s (TMs) in 10 vegetable types including leafy vegetables (purslane, purple basil and parsley) and fruiting vegetables (pepper, tomato, eggplant, cucumber, zucchini, green bean and melon) and in maize grown in Malatya province (Turkey) were investigated and non-carcinogenic health risks from consumption of these crops were assessed. The levels of TMs were measured by inductively coupled plasma-optical emission spectrometry. The mean levels of Ni, Cu, Cd, Cr, As and Zn in all crops were below maximum permissible concentrations (MPCs), while those of Pb in pepper (0.109 mg/kg fw), eggplant (0.103 mg/kg fw) and green bean (0.177 mg/kg fw) slightly exceeded MPCs (0.1 mg/kg fw). Leafy vegetables had relatively higher concentrations of Al, As, Ba, Cr, Cu, Fe and Mn compared to fruiting vegetables and maize. The estimated daily intake value of each TM estimated for each crop was found to be below the tolerable daily intake value. The target hazard quotients of all TMs in all crops did not exceed the acceptable non-carcinogenic risk level. However, hazard index (HI) value (1.57) in tomato was found to be above the threshold value of 1, indicating non-carcinogenic risks for consumers due to the intake of combined TMs in tomato. The THQ values of As, Co and Pb contributed 46.4%, 24.5% and 16.4% of the HI value of tomato, respectively. High daily consumption amount of tomato likely resulted in high HI value. The findings obtained in this study reveal that even if the levels of TMs in vegetables are safe, more attention should be paid to non-carcinogenic risks associated with TMs as a result of high vegetable intake.Öğe Arsenic and trace metals in a large reservoir: Seasonal and spatial variations, source identification and risk assessment for both residential and recreational users(Elsevier, 2019) Varol, MemetThe 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.Öğe Characteristics of effluents from trout farms and their impact on water quality and benthic algal assemblages of the receiving stream(Elsevier, 2020) Varol, Memet; Balcı, MustafaIn this study, characteristics of effluents from three flow-through rainbow trout farms in Turkey and their impact on water quality and epilithic algal communities of the receiving stream were investigated. Water samples were taken monthly from both inlets and outlets of three fish farms, while both water and epilithic algae samples were collected from two stations (upstream and downstream) in the stream. A significant increase from inlets to outlets was observed for chemical oxygen demand (COD), soluble reactive phosphorus (SRP), total suspended solids (TSS), NH4–N and total phosphorus (TP) (p < 0.05) due to no effluent treatment processes and high FCR at the fish farms. The daily average total nitrogen (TN) and TP fluxes of the fish farms predicted with the nutritional method were found close to those measured with the hydrological method. Although there were significant increases in COD, TSS, NH4–N, TN, NO3–N, NO2–N, TP and SRP concentrations at the downstream station compared to the upstream station of the receiving stream (p < 0.05), water quality of the downstream station remained in Class I in terms of examined parameters. Trophic Diatomic Index and Biological Diatom Index values indicated that the upstream station had a better water quality than the downstream station. Also, filamentous algae such as Cladophora glomerata, Ulothrix zonata and Stigeoclonium lubricum were observed at the downstream station. In view of the above findings, several suggestions were put forward to protect the water quality of the receiving stream.Öğe CO2 emissions from hydroelectric reservoirs in the Tigris River basin, a semi-arid region of southeastern Turkey(Elsevier, 2019) Varol, MemetThree hydroelectric reservoirs (Kralkizi, Dicle and Batman) in the Tigris River basin (Turkey) were sampled monthly during one year in order to reveal spatial and seasonal changes in aqueous partial pressure of CO2 (pCO(2)) and to estimate diffusive fluxes of CO2 from the reservoirs' surface water. pCO(2) concentrations did not show significant spatial differences, while they showed significant seasonal variations. Temperature, precipitation and biological CO2 uptake through photosynthesis controlled pCO(2) seasonality in the reservoirs, with maximal concentrations in the winter (ranging from 516.9 mu atm in Kralkizi to 1299.2 mu atm in Dicle) and minimal concentrations in the spring (ranging from 47.7 mu atm in Batman to 140.7 mu atm in Kralkizi). Most studies reported that reservoirs worldwide are net sources of CO2 to the atmosphere. However, the reservoirs in this study were sinks for atmospheric CO2 during the spring, summer and autumn seasons, while they were CO2 sources to the atmosphere during the winter. Air-water CO2 fluxes in Kralkizi, Dicle and Batman dam reservoirs were 2.39, 32.88 and 8.12 mmol/m(2)/day in the winter, respectively. On an annual basis, all three reservoirs acted as a sink for atmospheric CO2. These estimated CO2 fluxes were in the lower range for temperate reservoirs, despite the potential for winter conditions that shifted the reservoirs from sink to net source for atmospheric CO2.Öğe A comparison of trace element concentrations in surface and deep water of the Keban Dam Lake (Turkey) and associated health risk assessment(Elsevier, 2020) Canpolat, Özgür; Varol, Memet; Öztekin Okan, Özlem; Eriş, Kürşad Kadir; Çağlar, MetinKeban Dam Lake (KDL) is the second largest dam lake in Turkey. There have been some reports on the trace element (TE) levels in surface water of the KDL, but its deep water has been never studied. We measured 17 TEs (Pb, Hg, Cd, As, Cr, Ni, Co, Mn, Cu, Fe, Al, Sr, U, V, Zn, Zr and Ba) in surface and deep water samples and assessed their health risks for residential and recreational receptors. Copper, Zn, Ba, Ni, Mn and Pb levels in deep water were higher than those in surface water. Total TE level in deep water was higher in wet season, whereas that in surface water was higher in dry season. TE levels in both surface and deep water were much lower than the guideline values for drinking water and the protection of freshwater aquatic life, indicating that TEs in the KDL originate from natural sources. All HQ (hazard quotient) and HI (hazard index) values were below the risk threshold of unity. HI values for child were higher than those for adult, indicating that the health of children is at dramatically higher risk than adults. Arsenic and U for water ingestion were the primary contributors to total risk (HI), while V and Cr for dermal pathway. The presence of U and V, among the TEs which are major contributors to total health risk, reveals the necessity of monitoring of such less-studied elements in the surface water bodies. Carcinogenic risk values of As and Cr in surface and deep water were below the target risk of 1 × 10?4. These findings indicated that TEs in surface and deep water of the KDL do not pose health risks to residential and recreational users. Thus this study may serve as a model for similar studies assessing health risks of multi-elements in freshwater bodies in future.Öğe Ecological risks and controlling factors of trace elements in sediments of dam lakes in the Black Sea Region (Turkey)(Elsevier B.V. All, 2022) Varol, Memet; Ustaoğlu, Fikret; Tokatlı, CemThe 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.Öğe Environmental contaminants in fish species from a large dam reservoir and their potential risks to human health(Elsevier, 2019) Varol, Memet; Raşit Sünbül, MuhammetThe residue levels of antibiotics, metals and organochlorine pesticides (OCPs) were investigated in six fish species from the Karakaya Dam Reservoir, Turkey. Among monitored antibiotics, only enrofloxacin and ofloxacin were detected in muscle of fish species. Enrofloxacin levels in positive samples ranged from 0.0034 to 0.0073?mg/kg. It was detected in four fish species (trout barb, common carp, chub and Euphrates barbell), while ofloxacin was only found in common carp with the concentration of 0.0072?mg/kg. Both enrofloxacin and ofloxacin levels were below the maximum residue levels. No detectable residues of any OCPs were found in fish species. The highest toxic metal (As, Cd and Pb) content was detected in Euphrates barbell (0.103?mg/kg). Arsenic, Cd, Cr, Cu, Pb and Zn levels were well below the maximum permissible limits. The levels of antibiotics and metals found in fish species in the present study were generally lower than or comparable to those reported in other water bodies. According to estimated daily intake and hazard quotient values, antibiotics and metals detected in these wild fish species do not appear to pose a serious risk to public health.Öğe Environmental, ecological and health risks of trace elements, and their sources in soils of Harran Plain, Turkey(Elsevier, 2020) Varol, Memet; Sünbül, Muhammet Raşit; Aytop, Halil; Yılmaz, Cafer HakanSoil pollution with trace elements (TEs) has become an increasingly serious environmental concern, however, assessment of ecological and human health risks especially in intensive agricultural regions remains limited. In this study, the contents of ten TEs (Al, As, Pb, Cr, Cu, Zn, Ni, Co, Mn and Fe) in soil samples from 204 sampling sites in the Harran Plain (Turkey) were examined to evaluate possible sources, pollution status and environmental, ecological and health risks of these elements. Only As and Ni exceeded the upper continental crust concentrations. Among ten TEs, Ni and As had the highest mean values of enrichment factor (EF) and contamination factor (Cf), indicating that soils showed moderate enrichment and moderate contamination with these elements. Ecological risk factor and ecological risk index values of all samples were <40 and <150, respectively, indicating low ecological risk in the study area. Factor analysis and correlation analysis indicated that Al, Pb, Cr, Cu, Zn, Co, Mn and Fe mainly originated from natural sources, Ni from mixed sources of anthropogenic and lithogenic origins, while arsenic primarily originated from anthropogenic activities. The hazard quotient values for both adults and children did not exceed 1, suggesting that all TEs in soil through ingestion, dermal contact and inhalation pathways had no significant non-carcinogenic risks. Children were more susceptible to non-carcinogenic health effects of TEs in soils. The carcinogenic risk values of As, Co, Cr and Ni were within the acceptable risk range, indicating that carcinogenic risks were not expected.Öğe Environmental, ecological and health risks of trace metals in sediments of a large reservoir on the Euphrates River (Turkey)(Elsevier, 2020) Varol, MemetThe 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.Öğe Evaluation of health risks from exposure to arsenic and heavy metals through consumption of ten fish species(Springer, 2019) Varol, Memet; Kaya, Gülderen Kurt; Sünbül, Muhammet RaşitIn this study, the levels of 11 heavy metal(loid)s (HMs) were determined in ten different fish species (wild, farmed, freshwater, and marine) frequently consumed in Turkey and compared with the maximum permissible limits (MPLs) established by international standards. Also, human health risks for the consumers were assessed. Among 11 HMs, only Al and Cr levels did not show significant differences among fish species. The highest concentrations of As were found in red mullet, which is a demersal fish. The average concentrations of Cd, Cr, Cu, and Pb in all fish species were below the MPLs, whereas those of Zn in European anchovy and Mediterranean horse mackerel, and that of inorganic As in red mullet exceeded the MPLs. The highest and lowest toxic metal contents (Al, As, Cd, and Pb) were recorded in red mullet and farmed rainbow trout, respectively. The estimated daily intakes of HMs in each fish species were very lower than their corresponding tolerable daily intakes, suggesting the daily intake of HMs through fish consumption would not pose health risks for the consumers. The target hazard quotient for individual HMs and hazard index for combined HMs in fish species were below 1, which indicated that non-carcinogenic health effects are not expected. The carcinogenic risk results revealed that there was a carcinogenic risk from exposure to inorganic As via the consumption of red mullet. Among all investigated fish species, rainbow trout and common carp were safer in terms of both non-carcinogenic and carcinogenic risks from exposure to HMs.Öğe Impact of paddy fields on water quality of Gala Lake (Turkey): An important migratory bird stopover habitat(Elsevier, 2021) Varol, MemetGala 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.Öğe Impact of the COVID-19 lockdown period on surface water quality in the Meriç-Ergene River Basin, Northwest Turkey(Elsevier, 2021) Tokatlı, Cem; Varol, MemetThe surface water resources in the Meriç-Ergene River Basin, especially Ergene River and Çorlu Stream are among the most polluted rivers in Turkey. Despite the action plans for prevention and control of surface water pollution in the basin, the desired results have not been achieved. However, the implementation of a nationwide lockdown due to the COVID-19 might probably lead to an improvement in the surface water quality. We evaluated the impact of the lockdown on water quality by measuring the levels of physico-chemical variables and metal(loid)s in water samples taken from 25 sampling stations in the basin. BOD, COD, EC, turbidity, TSS and Mn levels did not show significant differences between the pre-lockdown and lockdown periods due to the ongoing domestic wastewater discharges and agricultural activities in the basin during the lockdown period. However, Cr, Ni, Zn, Cu, As, Pb and Cd concentrations decreased considerably during the lockdown. Similarly, heavy metal pollution index and heavy metal evaluation index values showed a significant improvement in water quality of almost all stations during the lockdown period. Also, total hazard index values for children and adults reduced by 67% and 69%, respectively during the lockdown period, while total carcinogenic risk values for As and Cr reduced by 60% and 94%, respectively. The limited operational status of most industrial facilities in the basin during the lockdown reduced the amount of industrial effluents, leading to significant improvement in surface water quality for metal(loid)s. The lockdown has shown that the solution for preservation and sustainability of natural water resources lies in our hands, and the efficient management of pollution sources can prevent surface water pollution at a very rapid pace. Finally, we suggest that water management policy needs to be improved and implemented.Öğe Impacts of cage fish farms in a large reservoir on water and sediment chemistry(Elsevier, 2019) Varol, MemetThe 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.Öğe Levels of metals and elements in tissues of fish species in the Kızılırmak River (Turkey) and assessment of health risks and nutritional benefits(Elsevier, 2022) Varol, Memet; Kaçar, Emel; Sünbül, Muhammet Raşit; Md Towfiqul Islam, Abu RezaAlthough the Kızılırmak River, the longest river in Turkey, is home to many fish species, there are a few studies reporting metal levels in fish in the river. The contents of 17 metals and elements (MEs) in various tissues of three fish species and surface water from the river were investigated. Significant differences in the ME levels among tissues were recorded, and the highest levels of most MEs were recorded in the gills and liver. The results revealed that correlations between MEs in tissues and fish size were not clear and consistent. Among the MEs, P (6058–109489) and Zn (933–47556) had the highest bioconcentration factor values. The levels of As and Cd in the river water exceeded water quality criteria. Health risk assessment methods (Target Hazard Quotient, Estimated Daily Intake and Lifetime Carcinogenic Risk) indicated that consumption of the studied fish species is safe. It was estimated that a weekly consumption of 490 g of C. gibelio, or 350 g of C. carpio or 280 g of T. tinca would not cause any health risks. Furthermore, it was found that fish species would provide significant benefits in terms of intake of nutrients such as P, K, Ca, Mg, Cu, Zn, Fe and Mn. These findings revealed that nutritional benefits from consumption of fish species outweigh the health risks posed by metals in fish.Öğe Macroelements and toxic trace elements in muscle and liver of fish species from the largest three reservoirs in Turkey and human risk assessment based on the worst-case scenarios(Elsevier, 2020) Varol, Memet; Sünbül, Muhammet RaşitMacroelement (Na, K, Ca, Mg and P) and toxic trace element (As, Cd and Pb) contents were investigated in muscle and liver of the two fish species (common carp and trout barb) from the largest three reservoirs (Atatürk, Keban and Karakaya) in Turkey. Also, human health risks for consumers using the worst-case scenarios were assessed. Potassium was the most abundant macroelement in muscle of both fish species in all reservoirs, whereas phosphorus was the most abundant in liver. Toxic trace element contents in the liver of the two fish species from the three reservoirs were higher than those in muscle. The mean levels of As and Pb in muscle and liver of fish species from the Karakaya Reservoir were higher than those from the other two reservoirs. Three-way ANOVA showed that the interaction between fish species, reservoir and fish tissue was significant for only Cd (p < 0.01). The maximum levels of As, Cd and Pb in muscle and liver of fish species from the three reservoirs were below permissible limits. The estimated daily intakes of toxic trace elements in fish species were much lower than their corresponding tolerable daily intakes. The target hazard quotient (THQ) and total THQ values in fish species were below 1, which indicated that non-carcinogenic health effects are not expected. The carcinogenic risk values for inorganic arsenic were within acceptable range. The results revealed that toxic trace elements in common carp and trout barb from the Atatürk, Keban and Karakaya reservoirs do not pose a significant health risk to consumers.Öğe Phytoplankton functional groups in a monomictic reservoir: seasonal succession, ecological preferences, and relationships with environmental variables(Springer, 2019) Varol, MemetThe seasonal succession of phytoplankton functional groups (PFGs), their ecological preferences, relationships between environmental variables and PFGs, and ecological status were investigated in the Batman Dam Reservoir, a warm monomictic reservoir, located in the Tigris River basin of Turkey. Altogether 60 species, 19 functional groups, and 10 prevailing functional groups were identified, and prevailing functional groups showed strong seasonal changes. Centric diatoms Cyclotella ocellata (group B) and Aulacoseira granulata (group P) were dominant in the spring, with water mixing and low temperature. Groups F (Elakatothrix gelatinosa, Elakatothrix gelatinosa, and Sphaerocystis schroeteri), J (Pediastrum simplex and Coelastrum reticulatum), G (Eudorina elegans and Volvox aureus), L-M (Ceratium and Microcystis), and H1 (Aphanizomenon flos-aquae and Anabaena spiroides) dominated the phytoplankton community from summer to mid-autumn, with thermal stratification. Groups H1 and P became dominant in the late autumn, with the breakdown of stratification. With the deepening of the mixing zone, groups P and T (Mougeotia sp.) were dominant in the winter. The reservoir was meso-eutrophic according to trophic state index values based on total phosphorus (TP), chlorophyll a, Secchi depth and total nitrogen, habitat preferences of PFGs, and diversity indices of phytoplankton. Redundancy analysis (RDA) revealed that NO3-N, SiO2, TP, pH, and water temperature (WT) were the most important environmental factors controlling PFGs in the BDR. Weighted averaging regression results indicated that among PFGs, groups F and T had a narrower tolerance range for WT, pH, and SiO2, while groups G and T had a narrower tolerance range for TP and NO3-N.Öğe Pollution status, potential sources and health risk assessment of arsenic and trace metals in agricultural soils: A case study in Malatya province, Turkey(Elsevier, 2021) Varol, Memet; Gündüz, Kazım; Sünbül, Muhammet RaşitWe measured the concentrations of arsenic and 11 trace metals in the soils from vegetable fields in Malatya province (Turkey) and assessed health risks for residential adults and children. Also, we assessed their potential sources, contamination status and ecological risks. Median concentrations of only As, Co, Ni and Cr exceeded the world soil average values, while those of Cd, As, Ni and Cu exceeded the upper continental crust contents. Contamination factor, enrichment factor and geoaccumulation index results indicated that the study region was contaminated with Cd, As, Ni and Cu likely due to use of irrigation water contaminated with industrial wastewaters and use of fertilizers and pesticides. Also, the study region had “high potential ecological risk” for Cd, whereas “low potential ecological risk” for the other trace metal(loid)s (TMs). Factor and hierarchical cluster analyses revealed that As and Cu were from anthropogenic sources, Cd and Ni from both natural and anthropogenic sources, while other TMs from natural sources. The hazard quotient values of all TMs and total hazard index values for both children and adults were lower than the risk level of 1, indicating that non-carcinogenic health risks are not expected for residents. Also, the cumulative carcinogenic risk results were within the acceptable risk range. Our results indicated that application of multivariate statistics, pollution, ecological and health indices together provide valuable knowledge for assessing soil pollution in a particular region.Öğe Seasonal variations of toxic metal(loid)s in groundwater collected from an intensive agricultural area in northwestern Turkey and associated health risk assessment(Elsevier, 2022) Varol, Memet; Tokatlı, Cemİpsala district located in the northwest of Turkey is an intensive agricultural area, where paddy cultivation has been carried out for more than 50 years. The main source for drinking water in the area is groundwater. Since large amounts of agrochemicals are applied to the paddy fields, groundwater in the study area can be contaminated with toxic metal (loid)s (TMs). In this study, levels of eight TMs in the drinking water samples taken from the district and its 22 villages in the dry and wet seasons were measured and compared with drinking water quality guidelines. In addition, non-carcinogenic and carcinogenic health risks, and pollution status of TMs were assessed. The mean values of Cd, Ni, Cu, Zn, Mn, Pb, As and Cr in both seasons were below the drinking water limits. High clay content and low infiltration rate of the soils in the study area may have caused low TM concentrations. The TMs levels were higher in the wet season due to high rainfall intensity. Metal pollution indices indicated that groundwater quality is suitable for potable uses. All hazard quotient and hazard index results for children and adults in both seasons were lower than the acceptable risk level of 1. Carcinogenic risk results of As and Cr in both seasons were within or below the acceptable risk range. These findings revealed that the TMs in the drinking water would not pose health risks to the local residents.Öğe Sediment contamination by trace elements and the associated ecological and health risk assessment: A case study from a large reservoir (Turkey)(Elsevier, 2022) Canpolat, Özgür; Varol, Memet; Öztekin Okan, Özlem; Eriş, Kürşad KadirAlthough Keban Reservoir (KR) is Turkey's the second largest man-made reservoir, limited data are available on the contents of trace elements (TEs) in sediments of the KR. The concentrations of 23 less- and commonly-monitored TEs in the sediments from 49 sites in the reservoir were measured to assess health risks, contamination levels and ecological risks of TEs. Concerning median Enrichment Factor values of TEs, chromium (Cr), strontium (Sr) and nickel (Ni) showed moderate enrichment, while other TEs showed minimal enrichment. Pollution Load Index values ranged from 0.33 to 0.63, indicating no a multi-element contamination case in the study area. Low ecological risk was found at 47 sites, while moderate ecological risk was recorded at two sites. The PEC (probable effect concentration) values were exceeded for Ni and Cr. Although wastewater from leather processing factory partly contributed to Cr enrichment at site 2, all TEs mainly originated from lithogenic sources. Median hazard quotient (HQ) values of zirconium (Zr) and lanthanum (La) for children from sediment ingestion were above the risk threshold of unity (HQ = 4.81 and 1.39) and contributed 62.9% and 18.2% of the total health risk. Such high HQ values of Zr and La have never been reported in the literature. Hazard index values for children exceeded those for adults, indicating that children are more vulnerable to health risks than adults. Carcinogenic risk values of arsenic (As) were within the acceptable limits. Our findings indicated that in a multi-element sediment study, some less-monitored elements such as Zr and La may have an important role in health risk assessment even if they are found in the sediment at low concentrations. Therefore, this study can be a model for future similar studies evaluating the health risks of multi-elements in sediments.
