1,721,015 research outputs found
Bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in Mediterranean mussel (<i>Mytilus galloprovincialis</i> Lamarck, 1819) along the southeastern Black Sea coast
No full textGedik, Kenan/0000-0001-8244-6935The adverse effect of seafood consumption on human health is related to the bioaccessibility in contrast with the total heavy metal level in the tissues. in this study, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) edible soft tissues collected along the southern Black Sea coast were investigated using in vitro digestion model. Total Pb concentration in the tissues was found to be higher than the maximum permissible limits set by European Commission. the bioaccessibility of metals in the tissues was found to be decreased in the order: Ni (83.11%) > Cu (80.47%) > Zn (76.86%) > Cd (73.32%) > Mn (69.11%) > Pb (61.07%) > Cr (58.44%). While significant positive linear regression was observed between total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regression was found for Cd (p < .05). the hazard quotients (HQ) calculated using bioaccessible amount were detected lower than the limit (HQ <1), which may not pose a potential hazard to humans reported by US Environmental Protection Agency. in sum, mussel consumption from sampling sites may cause a potential risk concerning human health especially for Cd and Pb in case of increased portion sizes.Research Fund of Recep Tayyip Erdogan UniversityRecep Tayyip Erdogan University [FBA-2016-594]This work was funded by the Research Fund of Recep Tayyip Erdogan University (Project Number: FBA-2016-594)
Health risk perspectives of metal(loid) exposure via consumption of striped venus clam (Chamelea gallina Linnaeus, 1758)
No full textOZTURK, Rafet Cagri/0000-0003-1785-4056; Gedik, Kenan/0000-0001-8244-6935The metal(loid)s are mainly transported to the Black Sea via rivers and affect the coastal area where fisheries are intensive. Chamelea gallina (striped venus clam) is the most abundant mollusk species in the Black Sea and used as a bioindicator for monitoring of metal(loid) pollution. in this respect, the concentrations of As, Cd, Cr, Cu, Pb, and Zn in C. gallina collected from 16 different locations along the Black Sea coast (Turkey, Bulgaria, and Russia) were determined and evaluated for the potential human health risk. the results obtained were found to be below the maximum permissible limits indicated in the food safety guidelines. Similarly, the analyzed metal(loid)s did not pose a potential hazard to humans for consumption of the C. gallina, regarding provisional tolerable weekly intake described by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Moreover, target hazard quotient and hazard index were found to be lower than 1 for not only average consumer but also the consumer who consumed a portion (160 g) once a week. in contrast, consumption of C. gallina could cause health risks for Cd and As in case of increasing portion sizes.Karadeniz Technical University, Research Project fund [FBA-2017-5635]The Chamelea gallina samples used in the present work were provided from the project supported by the Karadeniz Technical University, Research Project fund (Project No. FBA-2017-5635)
Bioaccessibility of heavy metals in rapa whelk <i>Rapana venosa</i> (Valenciennes, 1846): Assessing human health risk using an <i>in vitro</i> digestion model
No full textGedik, Kenan/0000-0001-8244-6935Instead of total metal concentration measurements in seafood, bioaccessibility is a more important parameter for human health risk assessment. Therefore, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in the edible soft tissues of rapa whelk (Rapana venosa Valenciennes, 1846) collected along the southern Black Sea coast were investigated using an in vitro digestion model. Zn was detected at the highest concentration, whereas Ni was the lowest for total metal concentrations. Total Cd and Pb concentration in the tissues were found to be higher than maximum permissible limits set by European Commission. the bioaccessibility of metals in the tissues was found to be decreased in the order: Cu (77.11%) > Cd (70.13%) > Zn (64.52%) > Ni (61.27%) > Pb (50.53%) > Cr (43.41%) > Mn (22.59%). While significant positive linear regressions were observed between the total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regressions were found for Cd in the tissues (p < 0.05). the hazard quotients (HQ) calculated using bioaccessible heavy metal amount were detected lower than the limit value (HQ < 1), which may not pose a potential hazard to humans declared by US Environmental Protection Agency. However, the consumption of rapa whelk may cause a potential risk concerning human health for the Cd and Pb levels in case of increased serving sizes and portions.Recep Tayyip Erdogan UniversityRecep Tayyip Erdogan University [FBA-2016-594]; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113Y148]This work was supported by the Research Fund of Recep Tayyip Erdogan University (Project Number: FBA-2016-594). the samples used in this study were obtained from the project (CAYDAG, Project No: 113Y148) supported by Scientific and Technological Research Council of Turkey
Microplastic pollution profile of Mediterranean mussels (Mytilus galloprovincialis) collected along the Turkish coasts
No full textGedik, Kenan/0000-0001-8244-6935Plastics profoundly threatens ecological balance in marine ecosystems across the globe in the current era of industrialization. Microplastics (MP), in particular, can pose risks reaching humans through the food web via various marine organisms. Among these organisms, since they are consumed as a whole, mussels are vital vectors of MP transfer during human consumption. Hence, here we analyzed MP pollution in Mediterranean mussel (Mytilus galloprovincialis) sampled from 23 different locations all along the Turkish coasts of the Black Sea, Sea of Marmara, and the Aegean Sea. After digestion of the mussels with H2O2, the micro-particles were determined under a stereomicroscope and characterized by confirming with FTIR analyses. 48% of the sampled mussels were found to have MPs. the average MP abundance was 0.69 item/mussel and 0.23 item/g fresh weight (fw) of soft tissue. Morphology was ordered as follows: fragments (67.6%)> fibers (28.4%)> films (4.05%). the dominant size of MPs was detected less than 0.5 mm (26.58%). 12 different polymers have been identified by FTIR and PET (32.9%), PP (28.4%), and PE (19.4%) were found to constitute 80% of the total MPs. the annual average exposure amount for mussel consumers in Turkey was estimated as 1918 MPs item/per year. Even though international organizations such as FAO, JECFA, or EU have not declared permissible limits, our data may inform human health uptake of MP ingestion via mussels. This data might also serve as a reference data-set for further MP monitoring research in Turkish and European Seas. (C) 2020 Elsevier Ltd. All rights reserved.Research Fund of the Recep Tayyip Erdogan University [FBA-2020-1094, FYL-2019-1033]This work was supported by the Research Fund of the Recep Tayyip Erdogan University (grant numbers: FBA-2020-1094 and FYL-2019-1033). We would like to express our gratitude to Erdinc Turanli for his precious support for mussel sampling. Also, we thank Necla Pehlivan for her language edit
Adsorption and desorption of arsenate in Louisiana rice soils
No full textGedik, Kenan/0000-0001-8244-6935Adsorption and desorption of arsenic (As) in the soil are dominant parameters that affect the mobility and bioavailability of arsenic. Batch arsenate adsorption and desorption experiments were conducted using soils collected from three Louisiana, USA, aquaculture ponds representing different crayfish farming and rice cultural practices. Arsenate adsorption behavior in the soils was investigated using Freundlich and Langmuir sorption equations. Results demonstrated that the Langmuir isotherm model was the best fit based on statistical correlation with soil properties governing adsorption, for the entire range of arsenate concentrations for all soils. Adsorption of As(V) was governed by soil physicochemical properties especially Fe and Al oxides, clay and organic matter. Desorption of As(V) was initially fast, but with increasing incubation times desorption occurred progressively slower. Chemical fractionation of arsenic in the soils showed that the most mobile fraction represented 4.74-5.18% of the total arsenic. A part of this mobile fraction could potentially be taken up by rice and enter the food chain, but would require additional research to quantify
Distribution of arsenic and other metals in crayfish tissues (Procambarus clarkii) under different production practices
No full textGedik, Kenan/0000-0001-8244-6935Louisiana is one of the world's largest producer of crayfish. Arsenic (As) and other metals (Cd, Cu, Pb and Zn) concentrations were determined in crayfish tissues, plant and soil samples collected from Louisiana paddy rice fields, where crayfish/rice rotation farming is a common practice. the samples were collected from November 2013 to April 2014 from three different crayfish farming systems. Concentration of As in rice grain, rice straw, and native vegetation ranged between 033 and 0.41, 3.14-4.93, and 326-5.89 mg kg(-1), respectively. the highest As levels in the crayfish external and internal body parts were found in gill (4.04 +/- 1.70 mg kg(-1)), followed by hepatopancreas (3.42 +/- 1.57 mg kg(-1)), exoskeleton (1.52 0.85 mg kg(-1)), and muscle (1.50 +/- 0.69 mg kg(-1)). Positive correlations between As levels in the crayfish muscle and the plant tissue on which they feed were found in all farming systems (r = 0.405-0.438). the biomagnification factor (BMF) of As in different tissues varied between 0.29 and 1.08, having gill and hepatopancreas were the highest As accumulation while the lowest biomagnification was observed in crayfish muscle tissues which is a food source for human. the As levels along with other metals in crayfish muscle tissue were in acceptable levels for human consumption under all crayfish/rice rotation practices. Further studies are needed in determining the percentage of organic and inorganic arsenic in crayfish tissue. Published by Elsevier B.V.Council of Higher Education of TurkeyMinistry of National Education - TurkeyWe would like to thank the Council of Higher Education of Turkey for supporting Kenan Gedik. We also thank William (Ray) McClain for suggestions and comments on the manuscript
Biomonitoring of metal(oid)s in mining-affected Borcka Dam Lake coupled with public health outcomes
No full textTerzi, Ertugrul/0000-0003-2811-6497; YESILCICEK, TUNCAY/0000-0002-3236-8227; Gedik, Kenan/0000-0001-8244-6935Due to increased anthropogenic activities, the aquatic environment is exposed to pollutants much more than ever. These pollutants go into the food chain and can pose a health risk to human. Correlatively, Borcka Dam Lake, Turkey has been affected by mining activities since decades. in the present study, therefore, Cu, Pb, As, Zn, Mn, Cd, Cr, and Se concentrations in water, sediment, and different tissues (muscle, gill, liver) of 11 fish species sampled from the lake were analyzed regarding metal(oid)s pollution and potential human health risk through fish consumption. the metal(oid) concentrations in the water were below the limit values recommended by USEPA for aquatic life criteria but sediments were heavily polluted by As, Cu, Pb, and Zn based on Sediment Quality Guideline. the lowest metal(oid) values among tissues for all fish species were determined in muscle (p < 0.05) which was lower than the limits for human consumption declared by European Union Regulation. Target Hazard Quotient and Hazard Index used non-cancer risk estimate which was lower than 1. in the view of these results, the consumption of fish caught from the Borcka Dam Lake may not pose a potential risk to human.Research Fund of Recep Tayyip Erdogan UniversityRecep Tayyip Erdogan University [FBA-2016-670]This work was funded by the Research Fund of Recep Tayyip Erdogan University (Project Number: FBA-2016-670)
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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