Nüket Sivri

Class 1 and class 2 integrons and plasmid-mediated antibiotic resistance in coliforms isolated from ten rivers in northern Turkey

We aimed to determine the molecular mechanisms of antibiotic resistance in coliforms isolated from ten rivers in northern region of Turkey. A total of 183 isolates were tested for antimicrobial susceptibility by disk diffusion and agar dilution methods. Resistance to ampicillin, streptomycin, trimethoprim, tetracycline, and chloramphenicol was detected in 58%, 51.9%, 24%, 28.4%, and 12.5%, respectively. Twelve (6.5%) phylogenetically distant organisms were detected to harbor self-transmissible plasmids ranging 52 to >147 kb in sizes. Resistances to ampicillin, tetracycline, trimethoprim, streptomycin, and nalidixic acid were commonly transferable traits. Transferable nalidixic acid-resistant strains harbored qnrS gene, which was the first report of plasmid-mediated quinolone resistance in bacteria of environmental origin in Turkey. Fourteen and five coliforms harbored class 1 and class 2 integrons, respectively, and some of them were located on transferable plasmids. Sequence analyses of variable regions of the class 1 and 2 integrons harbored various gene cassettes, dfrA1, dfr2d, dfrA7, dfrA16, dfrA17, aadA1, aadA5, blaoxA-30, and sat1. A gene cassette array, dfrA16 has been demonstrated for the first time in a Citrobacter koseri isolate. Class 1 and class 2-bearing strains were clustered in different groups by BOX-PCR fingerprinting. Rivers in the northern Turkey may act as receptacle for the multi-drug resistant enterobacteria and can serve as reservoirs of the antimicrobial resistance determinants in the environment. The actual risk to public health is the transfer of resistance genes from the environmental bacteria to human pathogens.

Freshwater plastic pollution: Recognizing research biases and identifying knowledge gaps

The overwhelming majority of research conducted to date on plastic pollution (all size fractions) has focused on marine ecosystems. In comparison, only a few studies provide evidence for the presence of plastic debris in freshwater environments. However, owing to the numerous differences between freshwater studies (including studied species and habitats, geographical locations, social and economic contexts, the type of data obtained and also the broad range of purposes), they show only fragments of the overall picture of freshwater plastic pollution. This highlights the lack of a holistic vision and evidences several knowledge gaps and data biases. Through a bibliometric analysis we identified such knowledge gaps, inconsistencies and survey trends of plastic pollution research within freshwater ecosystems. We conclude that there is a continued need to increase the field-data bases about plastics (all size fractions) in freshwater environments. This is particularly important to estimate river plastic emissions to the worlds oceans. Accordingly, data about macroplastics from most polluted and larger rivers are very scarce, although macroplastics represent a huge input in terms of plastics weight. In addition, submerged macroplastics may play an important role in transporting mismanaged plastic waste, however almost no studies exist. Although many of the most plastic polluted rivers are in Asia, only 14% of the reviewed studies were carried out in this continent (even though the major inland fisheries of the world are located in Asias rivers). The potential damage caused by macroplastics on a wide range of freshwater fauna is as yet undetermined, even though negative impacts have been well documented in similar marine species. We also noted a clear supremacy of microplastic studies over macroplastic ones, even though there is no reason to assume that freshwater ecosystems remain unaffected by macro-debris. Finally, we recommend focusing monitoring efforts in most polluted rivers worldwide, but particularly in countries with rapid economic development and poor waste management.

Culturable airborne bacteria and isolation of methicillin-resistant coagulase-negative staphylococci from outdoor environments on European side of Istanbul, Turkey

Abstract This study is aimed to investigate culturable airborne bacteria concentrations and the composition of methicillin-resistant staphylococci in eleven different locations on the basis of specific activities conducted within different parts of the European side of Istanbul. The highest bacterial levels were observed at the Bakirkoy station (1 100 CFU/m3) while the second highest levels were found at the Bahcelievler station (1 040 CFU/m3) in October; the lowest levels (10 CFU/m3) were measured at other different stations (Atakoy, Yesilkoy). Fifteen methicillin-resistant isolates [Staphylococcus hominis (n=11), S. cohnii spp. cohnii (n=2), S. sciuri (n=1), S. capitis spp. capitis (n=1)] were identified. The disc diffusion method was used to identify the antimicrobial resistance of these isolates, it was observed that the most common resistance was to penicillin (P) (n=11), doxycycline (DO) (n=4) and tetracycline (T) (n=5). None of the isolates was resistant to imipenem, amoxicillin/clavulanic acid, vancomycin (IPM, AMC, VA). However, multiple antimicrobial resistance was found to be 26.7%. The results of this study revealed the importance of isolated methicillin-resistant staphylococci in the stations with densely active human population and traffic, for public health. As a result, the importance of resting along known shorelines, where culturable airborne bacteria concentrations are much lower, and its importance for human health have been emphasized.

The relationship between income level and CFP level of the provinces in Turkey: a case study

This study determines the distribution of carbon footprint values (CFP) in Turkey by income levels, gender, age group, provinces where people live and the geographical regions of these provinces. In addition, % distribution of human activities which lead to CFP (food, travel, home, stuff) has been analysed. The carbon emission values assessed in this study have been compared with annual carbon emission distributions of various countries. In comparison by income levels, it was observed that mainly consumption-based usages (48%) take part in spending of people in the lowest income section while travel costs (42%) of people having high income have a significant contribution to CFP values. In assessment by age groups, it was observed that the highest CFP value is obtained by those aged 40 or older (in average; 17.1 tons CO2 per capita). In assessment of CFP values on the basis of geographical region and province, it was seen that high CFP values which result from the fuel type used for heating in eastern regions of Turkey replace CFP values related to transportation in western parts. In Turkey, annual carbon emission value is 15.1 tons CO2 per capita in average. This value is similar to annual carbon emission per capita of European countries such as Spain, France.

The relationship between particle and culturable airborne bacteria concentrations in public transportation

This study aims to determine the in-vehicle and outdoor culturable airborne bacteria concentration, fine particle (PM2.5) concentration and particle number concentration for six size ranges (0.3–0.5 µm, >0.5–1.0 µm, >1.0–3.0 µm, >3.0–5.0 µm, >5.0–10 µm, and >10 µm) and to assess the relation between the culturable airborne bacteria and PM2.5 concentrations in different public transport vehicles. The measurement campaign was conducted in the morning and evening onboard of the Metrobus, red-bus and outdoors. PM2.5 concentrations in the Metrobus and red-bus were observed as 58.8 ± 10.2 µg/m3 and 76.2 ± 30.9 µg/m3, respectively, and the outdoor value was about two times more. For both types of public transportation, the amount of internal environment particulate matter and the amount of external environment particulate matter displayed a high level of correlation (red-bus/outdoors, R = 0.97; Metrobus/outdoors, R = 0.88) with the particulate matter size. The concentration of Staphylococcus aureus correlated with PM2.5 concentrations in the Metrobus and Staphylococcus spp. was found to be higher in in-vehicle. The number of commuters, vehicle ventilation type and outdoor air entering the vehicles probably caused the differences in in-vehicle culturable airborne bacteria and particle concentrations.

Modeling the toxicity of textile industry wastewater using artificial neural networks

Toxicity tests are required to detect the possible effects of pollutants on organisms. This study investigates the effect of Chemical Oxygen Demand (COD), suspended solid (SS) and pH parameters on toxicity of textile industry wastewaters except for the color parameter, effect of which is well known. Fish bioassay taking place in legal regulation of Turkey was used as toxicity test. At the end of the toxicity test, various values of the parameters were predicted through Artificial Neural Networks (ANN). In addition, Artificial Neural Networks were used to calculate the effect of each parameter on toxicity (%). Accordingly, COD is the parameter which mostly affects toxicity following color parameter and SS is the parameter which has the minimum effect. It is found that results deviate at the rate of 15.41% when values of COD parameter are excluded from the model input data and the error rate becomes 5.07% when SS parameter is excluded. In this study, the effect of each input of each parameter, which is an open ecosystem, based on selected parameters is successfully predicted through Artificial Neural Networks which is a heuristic method.

The 2nd International Conference on Recycling and Reuse, held on June 4–6, 2014, in Istanbul, Turkey

This special issue of the Desalination and Water Treatment Journal is dedicated to the 2nd International Conference on Recycling and Reuse, held on 4–6 June 2014 in Istanbul, Turkey. This international conference was jointly organized by Boğaziçi University, Environmental Sciences Institute and Istanbul University, Environmental Engineering Department, Turkey. The purpose of the conference was to provide an excellent platform for researchers and practitioners to exchange emerging ideas and investigate key issues such as:

Determination of the Toxicity of Different Discharge Waters using Acute Toxicity Tests Approved for National Pollutant Discharge Permit in Turkey

Nowadays, three methods which target the evaluation of the characteristics of ecotoxicology tests according to aquatic trophic level are well-known, approved methods. In Turkey, the toxicity dilution factor (TDF) method, approved by Turkish Water Pollution and Control Regulation, and Lebistes reticulatus the actual method name that utilizes this animal which is a high level consumer, are used in the assessment of acute toxicity levels of waste waters with different compositions. However; it is not preferred by researchers except statutory obligations due to its disadvantages in implementation. The other method Daphnia magna, which belongs to secondary trophic group, is also widely used. Vibrio fischeri which is based on bioluminescent bacteria is mostly preferred due to ability of giving fast and precise results in acute toxicity assessment tests. In this study, specific to Turkey, it is aimed to compare issues such as experimental process, time, cost, efficiency, repeatability, etc. of tests that take place in the related legislation and standards. In light of all this information, it is determined the insufficient parts about legal regulations related to toxicity in Turkey. It can be suggested that bioluminescence bacteria (V. fischeri), defined all around the world recently with its precision, optimal cost, repeatability features be used in Legal Regulations of Turkey. It is aimed to contribute to scientific literature, this study being the first on suggesting an innovative approach about acute toxicity test in Turkey.

Landscape-based integrated water resources management in Nakhchivan Autonomous Republic

This study examines the potential for integrated water resource management in Nakhchivan Autonomous Republic, Azerbaijan. Water shortage and rainfall are calculated with data obtained from water observation station in districts, meteorology and irrigated agricultural fields. The scope of water shortage is visualised by means of geographical information systems based on land use analysis. The results showed that water demand is generally met by surface water resources across the country. In addition to drought, water shortages occasionally occur due to variations in seasonal rainfall and evaporation. The results also showed that the year 2008 had more severe drought conditions than 2004 and 2009, which was caused by low rainfall.