Investigation of the bacterial load and antibiotic susceptibility of dental units

The aim of this study was to evaluate the bacterial contamination level and to determine the antibiotic susceptibility of the isolated bacteria from dental unit waterlines (DUWLs) in Istanbul. Bacterial quality of DUWLs is very important, as patients and dental staff are regularly exposed to water and aerosols generated by the unit. If opportunistic pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, and Legionella pneumophila are present in DUWLs, patient and dental staff can be infected. One hundred water samples were collected from high-speed drills and input waters from 50 dental units. Aerobic heterotrophic bacteria counts and the presence of Legionella, Pseudomonas, oral streptococci, and Staphylococcus were investigated in dental unit waters and aerosol samples. In addition, the antibiotic susceptibility of the isolated and identified bacteria from DUWLs was examined. This research found that 37 out of 50 dental unit water samples exceeded the American Dental Association’s limit of 200 colony-forming units (CFU)/mL^?1. Legionella, oral streptococci, and S. aureus were not detected in any water or aerosol samples, but P. aeruginosa was isolated in three DUWLs. Also, Pseudomonas and Staphylococcus were found in water and aerosol samples. Cefoperazone, ofloxacin, gentamicin, ciprofloxacin, and piperacillin were the most effective antibiotics against the isolated bacteria from DUWLs.     

Synchronous variation in water chemistry for 80 lakes in Southern Sweden

Variation in water chemistry was studied in 80 lakes in southern Sweden. The lakes had forest dominated catchments. The length of the time series was 14 years. Synchrony was calculated as Pearsons product moment correlation coefficients for all combinations of lakes, i.e. 3160 lake-pairs. The chemical variables studied were non-marine sulphate (SO₄ ^*), non-marine calcium (Ca^*), absorbance and acid neutralising capacity (ANC). Statistically significant synchrony occurred in 93% of all lake-pairs for SO₄ ^*, and between 58 and 67% for absorbance, Ca^* and ANC. In 70% of all lake-pairs, the synchrony was \s>0.71 for SO₄ ^*, which means that more than half of the variation in one lake could be explained by the variation in the other lake. For absorbance, Ca^* and ANC, about 25% of the lake-pairs had a synchrony \s>0.71. The relatively high synchrony for SO₄ ^* occurred during an overall downward trend in SO₄ ^* concentration.The degree of synchrony in our study was at a level comparable to other studies in northern America and England. However, our study included lakes in a much larger area, with distances of up to 500 km between the lakes, while earlier studies were made on small lake districts with lakes located within approximately 50 km. In contrast to these earlier studies, there was no correlation between synchrony and distance, lake characteristics or catchment characteristics. However, when a small subset of 15 lakes in the southeast of Sweden was selected, such relations were found.     

Biomonitoring of polycyclic aromatic hydrocarbons in urban and industrial environments of the Western Black Sea Region,Turkey

This research was carried out in the cities of Zonguldak and Eregli, which have been characterized as urban and industrial environments of the Western Black Sea Region, Turkey, in order to assess the contamination of polycyclic aromatic hydrocarbons (PAHs) using mosses as biomonitors. The methodology involved the collection of moss samples (Hypnum cupressiforme), ultrasonic extraction with dichloromethane, cleanup using silica gel and analysis by liquid chromatography with ultraviolet detection. The total PAH concentrations ranged from 78.1 to 1693.5 ng g^?1 in Zonguldak and from 15.2 to 275.1 ng g^?1 in Eregli. The total PAH concentration in Eregli was about six times lower than that in Zonguldak, revealing the importance of switching from coal to natural gas in residential heating. The diagnostic ratios and the correlation analysis have indicated that coal combustion and traffic emissions were the major PAH sources at both sites. The contour maps were constructed for the determination of spatial distributions of total PAHs, and it was shown for Zonguldak as well as for Eregli that the PAH pollution was much more predominant in highly populated regions. Moving away from the city centres, a gradual decrease in PAH pollution rates was observed.     

Effect of addition diatomite powder on mechanical strength,elevated temperature resistance and microstructural properties of industrial waste fly ash-based geopolymer

This study examines the use of fly ash, a thermal power plant waste, and the effect of diatomite, a fossil algae type, on waste-based geopolymers in the production of sustainable geopolymer binders. The effects of 1%, 2%, 3%, 4% and, 5% diatomite substitution on waste-based mortars were investigated. Mortars containing 10% and 12% Na⁺ by weight based on the binder material were cured at 75 °C for 48 h. The flexural and compressive strength, abrasion resistance, determination of ultrasonic pulse velocity, and resistance to high temperatures of geopolymer mortar samples were investigated. In addition, FESEM images, EDX and XRD analyses of geopolymer mortar samples were made, and their microstructures were examined. 2% diatomite substitution increased flexural and compressive strength. In parallel with this situation, it was concluded that the abrasion resistance and ultrasonic pulse velocity of the geopolymer mortar with 2% diatomite substituted increased. In addition, it has been shown in FESEM images that the microstructure has a denser morphology. All geopolymer mortars lost strength after the high temperatures of 300 °C, 600 °C and 900 °C. As a result, it was concluded that diatomite containing highly reactive silica can be used in geopolymer systems.

     

An improved user-based beach climate index

In many coastal resort areas of the world, it is likely that optimal climatic conditions for beach use might occur outside the peak of the tourist season. Investigation of this issue together with associated publicity might help to spread the tourism load and hence reduce undesirable social and environmental effects of extreme seasonality in tourist demand. For this to take place, better knowledge of beach user preferences in terms of climate and bathing water temperature is required. Questionnaire surveys were carried out in Wales, Malta and Turkey to establish the preferences of north European beach users for thermal sensation and bathing water temperature, plus priority levels for other climatic attributes. A user-based beach climate index based on these preferences and priorities was formulated. Linkage was made between the user-generated ratings for various climatic conditions and published climate data to evaluate most major Euro-Mediterranean/Black Sea and a range of other beach tourism areas on a month-by-month basis. Results showed excessively hot thermal sensation in many southern and eastern Mediterranean coastal destinations during July and August, the present peak of the beach tourism season. Highest preference was given to water temperatures rather lower than those found in these areas during late summer. Many long haul coastal destinations popular with north European visitors had similar unpleasant thermal sensations over several months. Uncertainties and deficiencies still exist with the system, but from the point of view of north European beach users the final scores generated in this study may be regarded as good approximations of the quality of resort area climates for sedentary beach use.     

Influences of urban wastewaters on the stream water quality: a case study from Gumushane Province, Turkey

Urban wastewater in Turkey is primarily discharged without treatment to marine environments, streams and rivers, and natural and artificial lakes. Since it has been well established that untreated effluent in multi-use waters can have acute and chronic impacts to both the environment and human health, it is important to evaluate the consequences of organic enrichment relative to the structure and function of aquatic environment. We investigated the impacts of untreated municipal wastewater discharge from the city of Gumushane in the Eastern Black Sea Region of Turkey on the surface water quality of the stream Harsit. Several key water-quality indicators were measured: chemical oxygen demand (COD), ammonium nitrogen (NH ₄ ⁺ –N), nitrite nitrogen (NO ₂ ^? –N), nitrate nitrogen (NO ₃ ^? –N), total Kjeldahl nitrogen (TKN), total nitrogen (TN), orthophosphate phosphorus (PO ₄ ^3? –P), methylene blue active substances (MBAS), water temperature (t), pH, dissolved oxygen (DO), and electrical conductivity (EC). The monitoring and sampling studies were conducted every 15 days from March 2009 to February 2010 at three longitudinally distributed stations. While t, pH, DO, and EC demonstrated relatively little variability over the course of the study, other parameters showed substantial temporal and spatial variations. The most dramatic differences were noted in COD, NH ₄ ⁺ –N, NO ₂ ^? –N, TKN, TN, PO ₄ ^3— P, and MBAS immediately downstream of the wastewater discharge. Concentration increases of 309 and 418 % for COD, 5,635 and 2,162 % for NH ₄ ⁺ –N, 2,225 and 674 % for NO ₂ ^? –N, 283 and 478 % for TKN, 208 and 213 % for PO ₄ ^3? –P, and 535 and 1,260 % for MBAS were observed in the summer and autumn, respectively. These changes were associated with greatly diminished seasonal stream flows. Based on NO ₂ ^? –N, TKN, PO ₄ ^3— P, and MBAS concentrations, it was concluded that Harsit stream water was correctly classified as polluted. The most telling parameter, however, was NH ₄ ⁺ –N, which indicated highly polluted waters in both the summer and autumn. The elevated concentrations of both P and N in the downstream segment of the stream triggered aggressive growth of submerged algae. This eutrophication of river systems is highly representative of many urban corridors and is symptomatic of ongoing organic enrichment that must be addressed through improved water treatment facilities.     

Genotoxic risk assessment in professionals working hairdressers area using buccal micronucleus assay,in Aydın City,Turkey

The aim of this study was to determine the genotoxic risk of professional hairdressers in Ayd?n City, Turkey, through investigating the micronucleus frequencies in buccal mucosa epithelial cells. All the hairdresser working hairdresser area were included in the genotoxic risk group (GRG = 20) in Ayd?n City, Turkey. The control group (CG = 20) comprised healthy individuals matching the gender and age of the GRG. Buccal mucosal scraping from all the 40 subjects of GRG (10 women and 10 men) and CG (10 women and 10 men) was stained with Giemsa stain and observed under light microscope (×40) for the presence of micronuclei (M 10 N) and karyolysis, pyknosis, condensed chromatin, karyorrhexis, nuclear bud, and binucleates in the exfoliated epithelial cells. There are significance between the incidence of MN in GRG and CG (P = <0.005) using one-way ANOVA, Kolmogorov-Smirnov Z test, and Spearman Rank Correlation Tests.     

Increased deposition of polychlorinated biphenyls (PCBs) under an AC high-voltage power line

There is considerable public concern regarding the potential risks to health of electromagnetic fields in general and high-voltage power lines in particular. As epidemiological findings are not supported by a clearly defined mechanism of direct magnetic field interactions with the human body, potential indirect effects are of interest. It has been suggested that an increased exposure to chemical pollutants could occur near high-voltage power lines due to formation and deposition of charged aerosols. The current study reports empirical evidence that seems to support this hypothesis. The deposition of 18 congeners of polychlorinated biphenyls (PCBs) was studied by collecting samples of pine needles under a 400 kV AC power line and at reference sites in the vicinity. Compared to the reference sites, the average deposition of PCB congeners under the power line was almost double. This difference between the two groups of samples was statistically significant. While it is premature to draw any conclusions regarding the human exposure near high-voltage power lines, the issue deserves attention and further investigations.     

Sex ratio estimations of loggerhead sea turtle hatchlings by histological examination and nest temperatures at Fethiye beach, Turkey

Hatchling sex ratios in the loggerhead turtle (Caretta caretta) were estimated by placing electronic temperature recorders in 21 nests at Fethiye beach during 2000–2002. Over the seasons, the mean temperature in the middle third of the incubation period ranged from 26.7 to 32.1°C, and incubation periods ranged from 49 to 67 days. Based on the mean temperatures during the middle third of the incubation period, and on histologically sexed dead hatchlings, the sex ratios of hatchlings at Fethiye beach were roughly equal, i.e. 60–65% of the hatchlings were females. This contrasts with the highly female-skewed sex ratios in loggerhead turtles elsewhere; Fethiye has a relatively high proportion of male hatchlings. For endangered sea turtles, the knowledge of hatchling sex ratios at different beaches, coupled with appropriate conservation measures, can make an important contribution to their survival.