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Öğe Ecological and health risk assessment and quantitative source apportionment of dissolved metals in ponds used for drinking and irrigation purposes(Springer Heidelberg, 2023) Tokatli, Cem; Varol, Memet; Ustaoglu, FikretIn this study, dissolved metal levels of 10 different ponds used as irrigation and drinking water sources in the north of Saros Bay (Turkiye) were evaluated using multivariate statistical methods, contamination and ecological risk indices, and absolute principal component score-multiple linear regression (APCS-MLR). The mean levels of metals in the ponds ranged from 0.045 mu g/L (Cd) to 127 mu g/L (Mn). Pond 7 used for drinking water source had the lowest total metal level. Only Mn levels in two ponds (P1 and P2) slightly exceeded the critical value set by EU Drinking Water Directive. However, the levels of all metals in all ponds were lower than the critical values set for irrigation water and aquatic life. According to the heavy metal pollution index (HPI), five ponds showed low metal pollution in terms of drinking water quality, four ponds showed moderate metal pollution, and one pond (P1) showed moderate to heavy pollution. According to the Nemerow pollution index (NPI) values (0.26-1.82), ponds P1 and P2 showed slight metal pollution, while other ponds showed insignificant metal pollution. Contamination degree (CD) values of ponds varied between 0.95 and 3.33, indicating that all ponds showed low pollution. In terms of irrigation water quality, all ponds showed low or insignificant metal pollution according to the HPI, NPI, and CD values. According to the ecological risk index (ERI) values, metals in all ponds posed low ecological risks for both drinking and irrigation purposes. Factor analysis identified two potential sources: mixed sources and natural sources. The APCS-MLR model results revealed that mixed sources and natural sources contributed 78.99% and 21.01% to dissolved metals in the ponds, respectively. Health risk assessment results indicated that both individual and combined metals in the ponds would not cause non-carcinogenic risks to both adults and children. Similarly, it was found that Cr and As would not cause carcinogenic risks to the residents of the region.Öğe Ecological Risk Assessment of Metals in Sediments from Three Stagnant Water Bodies in Northern Turkey(Springer Heidelberg, 2022) Varol, Memet; Ustaoglu, Fikret; Tokatli, CemPurpose of Review In recent years, anthropogenic activities have caused metal pollution in the sediments of stagnant water bodies, and thus threatening aquatic ecosystems and human health. Therefore, determining the potential ecological risks, contamination degree, and possible sources of metals in sediment of stagnant water bodies is essential for effective management of metal pollution. In this study, we used contamination and risk assessment indices together with multivariate statistics to determine ecological risks and contamination degree of 14 metals in sediments of three important stagnant water bodies (Ladik Lake and Yedikir and Degirmendere dam lakes) in northern Turkey. In addition, the effects of organic matter (OM) and pH on metal accumulation in the sediments were also investigated. Recent Findings The mean contents of Al, V, Mn, Fe, Cu, Zn, and Pb did not differ significantly among the water bodies studied (p > 0.05). The Ladik Lake sediments had significantly lower pH level and higher OM content (p < 0.05). Contamination indices indicated that there was no significant metal contamination in the sediments of all water bodies. Similarly, ecological risk indices indicated that metals posed low ecological risks in the water bodies. According to the sediment quality guidelines, metals would not cause harm to benthic organisms. The accumulation of most metals in the Yedikir Dam Lake was controlled by OM, while the distribution of some metals was affected by both OM and pH in the Degirmendere Dam Lake. According to the factor analysis, all metals in the sediments of the water bodies studied mainly originated from natural sources. The results of this study revealed that sediment contamination indices, ecological risk assessment methods, sediment quality guidelines, and multivariate statistics can be used as effective approaches in determining the environmental and ecological risks and pollution sources of metals in the sediments of stagnant water bodies. Thus, this study can provide important information for the ecological risk assessment and management of metals in the sediments of stagnant water bodies.Öğe Ecological risks and controlling factors of trace elements in sediments of dam lakes in the Black Sea Region (Turkey)(Academic Press Inc Elsevier Science, 2022) Varol, Memet; Ustaoglu, Fikret; Tokatli, 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 U.gurlu and Sarayduzu) 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 U.gurlu Dam Lake on the Yes ilirmak 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 Evaluation of the water quality of a highly polluted stream with water quality indices and health risk assessment methods(Pergamon-Elsevier Science Ltd, 2023) Varol, Memet; Tokatli, CemThe water quality of corlu Stream, located in the Thrace region of Turkiye, and exposed to intense industrial pressure, was evaluated by monitoring 10 toxic metals and 13 other water quality variables in the dry and wet seasons of 2021. Seven different water quality indices were applied to determine the pollution level at the sampling stations in the stream. In addition, human health risks from exposure to toxic metals in stream water via ingestion and dermal contact were evaluated. The results showed that the water quality at stations S2 and S3 of corlu Stream receiving domestic and industrial discharges are seriously polluted by NH4-N, PO4-P, COD, BOD5 and suspended solids according to surface water quality standards. In addition, these stations were highly polluted and had poor water quality according to the results of the water quality indices. The average Cr level at station S3 exceeded the permissible levels set for the protection of aquatic life due to effluent discharges from the leather factories. Considering the results of the health risk assessment methods, non-carcinogenic risks from ingestion of combined metals in stream water can be expected at station S3 for both children and adults and at station S2 for children. Also, it was estimated that Cr and As at station S3 may cause carcinogenic health risks for residents.Öğe Hydro-chemical assessment of fluoride and nitrate in groundwater from east and west coasts of Bangladesh and India(Elsevier Sci Ltd, 2022) Jannat, Jannatun Nahar; Khan, Md Sanjid Islam; Islam, H. M. Touhidul; Islam, Md Saiful; Khan, Rahat; Siddique, Md Abu Bakar; Varol, MemetGroundwater from the coastal alluvial plain is the primary water source in coastal areas. Its contaminants, such as nitrate and fluoride, are significant concerns for freshwater supply and human health issues. Although spatiotemporal variability of nitrate and fluoride levels has been analyzed individually in the Indo-Bangladesh coastal region, their drivers and hydro-chemical analysis have scarcely been studied. Thus, to assess the groundwater quality, hydro-chemistry, and drivers in coastal alluvial aquifers, 123 groundwater samples were collected from the east (Bangladesh) and west coasts (India) for assessment of nitrate and fluoride levels and major physiochemical parameters. Multivariate statistical and hydro-chemical analysis and public health risk appraisal were carried out for this purpose. The results showed that 25% (East coast) and 22.39% (West coast) of groundwater samples surpassed the allowable limit of fluoride with a maximum concentration of up to 16.11 mg/L and the tolerable nitrate limit slightly exceeded 10 mg/L. Furthermore, we note that industrial waste, synthetic pesticides, and agricultural fertilizer triggered the leaching of nitrate into groundwater, while the release of fluoride into groundwater was possibly due to evaporite dissolution, carbonate mineral weathering, and ion exchange processes on both coasts. About 28.36% (26.79%) of groundwater samples possessed poor quality on the east (west) coasts. Considering the uncertainties of the variables, the mean hazard quotient ingestion values of fluoride faced by children (adults) were 10.5 (1.39) and 5.56 (6.9 x 10-1), respectively, on the east (west) coasts, demonstrating a high non-carcinogenic risk to people, particularly, children, who cannot be neglected. Children had two times higher health risks than the adult inhabitants in both regions studied. Probabilistic models can reveal health risks more extensively than deterministic models. This study came up with strategies for improving sustainable groundwater quality and managing health risks in coastal regions.Öğe Impact of paddy fields on water quality of Gala Lake (Turkey): An important migratory bird stopover habitat(Elsevier Sci Ltd, 2021) Varol, Memet; Tokatli, CemGala 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 Meric-Ergene River Basin, Northwest Turkey(Academic Press Inc Elsevier Science, 2021) Tokatli, Cem; Varol, MemetThe surface water resources in the Meric-Ergene River Basin, especially Ergene River and corlu 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 Metals and phosphorus in the sediments of streams emptying into the Çanakkale strait (Dardanelles): Spatial distribution, pollution status, risk assessment and source identification(Academic Press Inc Elsevier Science, 2024) Varol, Memet; Tokatli, CemThe & Ccedil;anakkale Strait is exposed to various pollutants due to its strategic location. It is thought that stream inputs may contribute significantly to metal and phosphorus (P) accumulation in the strait. In this study, the spatial distribution, pollution status, ecological risks and possible sources of twelve metals and P in the sediments of seven important streams emptying into the strait were analyzed. The results showed that Zn (226 mg/kg), Ba (67.2 mg/kg) and Pb (10.4 mg/kg) concentrations were higher in the Umurbey Stream due to mining activities, while P concentration (295 mg/kg) was higher in the & Ccedil;anakkale Stream due to both agricultural activities and domestic wastewater discharges. Modified hazard quotient (mHQ), enrichment factor (EF) and contamination factor (Cf) values revealed that Zn and Pb showed high and moderate contamination in the US3 and US4 sampling sites of the Umurbey Stream, respectively. Similarly, P showed moderate contamination in the & Ccedil;S3 site of the & Ccedil;anakkale Stream. Nemerow pollution index (NPI) showed that the US3 (2.41) and US4 (4.28) sites of the Umurbey Stream were slightly and moderately polluted, respectively. Toxic risk index (TRI) values demonstrated that the sediments in only the US4 site (5.17) of the Umurbey Stream may pose a low toxic risk due to high Zn content. Similarly, based on comparison results with sediment quality guidelines (SQGs), it was found that high Zn content may lead to adverse effects on sediment-dwelling organisms in the US4 site. In addition, the PECquotient value in the US4 site exceeded 0.5, confirming the finding that the sediments in this site could be toxic to benthic organisms. Finally, correlation, cluster and factor analyzes were used to determine possible sources of elements. Mining activities, natural sources and mixed sources (agricultural activities and natural sources) were identified as the main sources of elements in the sediments of the streams. This study can provide an important reference for evaluating stream sediment pollution and managing marine pollution.Öğe Seasonal variations of toxic metal(loid)s in groundwater collected from an intensive agricultural area in northwestern Turkey and associated health risk assessment(Academic Press Inc Elsevier Science, 2022) Varol, Memet; Tokatli, CemIpsala 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 Variations, health risks, pollution status and possible sources of dissolved toxic metal(loid)s in stagnant water bodies located in an intensive agricultural region of Turkey(Academic Press Inc Elsevier Science, 2021) Tokatli, Cem; Varol, MemetThere are many reservoirs, ponds and lakes in the Meric-Ergene River Basin (Turkey), which is an intensive agricultural region. Since agrochemicals are extensively applied to the agricultural soils in the basin, these water bodies may be contaminated with toxic metal (loid)s (TMs). However, no study has been conducted to determine TM levels in the water bodies. In this study, levels of seven TMs (Cr, As, Cu, N, Zn, Cd and Pb) in surface water samples taken from 25 different stagnant water bodies (11 reservoirs, 12 ponds and 2 lakes) in the dry and wet seasons were measured and compared with water quality guidelines. In addition, spatial and seasonal variations, health risks, pollution status and possible sources of TMs were assessed. The mean As concentration of the lakes was significantly higher due to drainage water from paddy fields. The ponds had higher total mean TM concentration likely due to their low water volume. Surface runoff from rainfall caused the Cr, Zn, Cd, Pb and Cu concentrations to increase in the wet season. Only the mean As concentration of the lakes in the dry season was above the drinking water standards. Metal pollution indices showed low contamination of the water bodies in both seasons. Health risk indices indicated that As in the lakes in the dry season via ingestion exposure pathway may pose both non-carcinogenic and carcinogenic health risks to the residents. The results of factor and correlation analyses showed that among the studied TMs, only As originated from anthropogenic sources. The findings of this study revealed that agricultural activities caused As pollution in the lakes, while the reservoirs and ponds were not significantly affected by agricultural activities. We suggest that the levels of TMs in all water bodies should be measured at regular intervals to check the quality of surface water.