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Exploring the Legionella pneumophila positivity rate in hotel water samples from Antalya, Turkey
2017
Sepin Özen, Nevgün | Tuğlu Ataman, Şenay | Emek, Mestan
The genus Legionella is a fastidious Gram-negative bacteria widely distributed in natural waters and man made water supply systems. Legionella pneumophila is the aetiological agent of approximately 90% of reported Legionellosis cases, and serogroup 1 is the most frequent cause of infections. Legionnaires’ disease is often associated with travel and continues to be a public health concern at present. The correct water management quality practices and rapid methods for analyzing Legionella species in environmental water is a key point for the prevention of Legionnaires’ disease outbreaks. This study aimed to evaluate the positivity rates and serotyping of Legionella species from water samples in the region of Antalya, Turkey, which is an important tourism center. During January−December 2010, a total of 1403 samples of water that were collected from various hotels (n = 56) located in Antalya were investigated for Legionella pneumophila. All samples were screened for L. pneumophila by culture method according to “ISO 11731-2” criteria. The culture positive Legionella strains were serologically identified by latex agglutination test. A total of 142 Legionella pneumophila isolates were recovered from 21 (37.5%) of 56 hotels. The total frequency of L. pneumophila isolation from water samples was found as 10.1%. Serological typing of 142 Legionella isolates by latex agglutination test revealed that strains belonging to L. pneumophila serogroups 2−14 predominated in the examined samples (85%), while strains of L. pneumophila serogroup 1 were less numerous (15%). According to our knowledge, our study with the greatest number of water samples from Turkey demonstrates that L. pneumophila serogroups 2−14 is the most common isolate. Rapid isolation of L. pneumophila from environmental water samples is essential for the investigation of travel related outbreaks and the possible resources. Further studies are needed to have epidemiological data and to determine the types of L. pneumophila isolates from Turkey.
Afficher plus [+] Moins [-]Urban biowaste-derived sensitizing materials for caffeine photodegradation
2017
Bianco Prevot, A. | Baino, F. | Fabbri, Donata | Franzoso, F. | Magnacca, G. | Nisticò, R. | Arques, A.
Caffeine-photosensitized degradation has been studied in the presence of bio-based materials derived from urban biowaste after aerobic aging. A peculiar fraction (namely bio-based substances (BBSs)), soluble in all the pH range, has been used as photosensitizing agent. Several caffeine photodegradation tests have been performed, and positive results have been obtained in the presence of BBSs and H₂O₂, without and with additional Fe(II) (photo-Fenton-like process). Moreover, hybrid magnetite-BBS nanoparticles have been synthesized and characterized, in order to improve the sensitizer recovery and reuse after the caffeine degradation. In the presence of such nanoparticles and H₂O₂ and Fe(II), the complete caffeine degradation has been attained in very short time. Both homogeneous and heterogeneous processes were run at pH = 5, milder condition compared to the classic photo-Fenton process.
Afficher plus [+] Moins [-]Short-term effects of air pollution on daily hospital admissions for cardiovascular diseases in western China
2017
Ma, Yuxia | Zhang, Haipeng | Zhao, Yuxin | Zhou, Jianding | Yang, Sixu | Zheng, Xiaodong | Wang, Shigong
Controlling the confounding factors on cardiovascular diseases, such as long-time trend, calendar effect, and meteorological factors, a generalized additive model (GAM) was used to investigate the short-term effects of air pollutants (PM₁₀, SO₂, and NO₂) on daily cardiovascular admissions from March 1st to May 31st during 2007 to 2011 in Lanzhou, a heavily polluted city in western China. The influences of air pollutants were examined with different lag structures, and the potential effect modification by dust storm in spring was also investigated. Significant associations were found between air pollutants and hospital admissions for cardiovascular diseases both on dust event days and non-dust event days in spring. Air pollutants had lag effects on different age and gender groups. Relative risks (RRs) and their 95% confidence intervals (CIs) associated with a 10 μg/m³ increase were 1.14 (1.04~1.26) on lag1 for PM₁₀, 1.31 (1.21~1.51) on lag01 for SO₂, and 1.96 (1.49~2.57) on lag02 for NO₂ on dust days. Stronger effects of air pollutants were observed for females and the elderly (≥60 years). Our analysis concluded that the effects of air pollutants on cardiovascular admissions on dust days were significantly stronger than non-dust days. The current study strengthens the evidence of effects of air pollution on health and dust-exacerbated cardiovascular admissions in Lanzhou.
Afficher plus [+] Moins [-]Occurrence and risk assessment of trace metals and metalloids in sediments and benthic invertebrates from Dianshan Lake, China
2017
Wu, Yan | Zhou, Yihui | Qiu, Yanling | Chen, Da | Zhu, Zhiliang | Zhao, Jianfu | Bergman, Åke
The present study measured concentrations of Cr, Ni, Cu, Zn, As, Cd, Sb, and Pb in surface sediments and two benthic invertebrate species (Anodonta woodiana and Bellamya aeruginosa) collected from Dianshan Lake, located in the Yangtze River Delta. The Dianshan Lake acts as one of the most important drinking water sources to Shanghai, the biggest city in China. Concentrations of trace metals and metalloids ranged from 0.04 mg/kg for Cd to 288.0 mg/kg for Zn. Substantial bioaccumulation in invertebrates was observed for Zn and Cu based on the biota-sediment accumulation factor (BSAF) measurements. The results revealed that concentrations of metals and metalloids in sediments from Dianshan Lake were at the lower end of the range of levels found in other regions of China. The assessment of three significantly inter-related evaluation indices, including the geo-accumulation Index (Igₑₒ), potential ecological risk factor (Erⁱ), and mean probable effect concentration quotients (Qₘ₋PEC), suggested that sediment-associated trace elements exhibited no considerable ecological risks in the studied watershed. However, the target hazard quotient and hazard index analysis suggested that selected elements (particularly As) accumulation in edible tissues of benthic invertebrates could pose potential health risks to local populations, especially fishermen. Given that wild aquatic organisms (e.g., fish and bivalves) constitute the diet of local populations as popular food/protein choices, further investigations are needed to better elucidate human health risks from metal and metalloid exposure via edible freshwater organisms.
Afficher plus [+] Moins [-]Comparing the photocatalytic activity of TiO2 at macro- and microscopic scales
2017
Torras-Rosell, Antoni | Johannsen, Sabrina Rostgaard | Dirscherl, Kai | Daviðsdóttir, Svava | Jeppesen, Christian Sloth | Louring, Sascha | Andersen, Inge Hald
This study focuses on the characterization of photocatalytic TiO₂ coatings using Kelvin probe force microscopy. While most photocatalytic experiments are carried out at a macroscopic scale, Kelvin probe force microscopy is a microscopic technique that is surface sensitive. In order to link microscale results to macroscopic experiments, a simple method to establish the relation between Kelvin probe force microscopy and electrochemical measurements is presented by the calibration of a reference sample consisting of epitaxial deposited Cu-Ni-Au that is used as a transfer standard. The photocatalytic properties of TiO₂ at macro- and microscopic scales are investigated by comparing photocatalytic degradation of acetone and electrochemical experiments to Kelvin probe force microscopy. The good agreement between the macro- and microscopic experiments suggests that Kelvin probe force microscopy can be a valuable tool towards the understanding, standardization and design of TiO₂-based solutions in photocatalytic applications.
Afficher plus [+] Moins [-]Spatial distribution of atmospheric PAHs and their genotoxicity in petrochemical industrialized Lanzhou valley, northwest China
2017
Wang, Li | Zhao, Yuan | Yi, Xin | Wang, Zhanxiang | Yi, Yayi | Huang, Tao | Gao, Hong | Ma, Jianmin
The present study investigated the spatial and seasonal variations and sources of 16 priority polycyclic aromatic hydrocarbons (PAHs) in Lanzhou, a petrochemical industrialized and the capital city of Gansu province, northwest China. The human health risks to these PAHs were assessed using an in vitro genotoxic bioassay technique. Associations among direct genotoxic potency, atmospheric PAH concentrations, and potential carcinogen risks were examined. Due to high PAH emissions from fossil fuel combustion and petrochemical industries, considerable higher PAH levels in the atmosphere were observed in Xigu district, a suburb featured by heavy petrochemical industry, compared with those collected at downtown and rural sampling sites. Ambient PAH levels at all sampling sites during the wintertime were higher than that in the summertime due to the winter domestic heating. BaP equivalent (BaPeq) concentrations in winter (41 ng/m³) and summer (28 ng/m³) exceeded the China’s new national daily BaPeq standard. The average excess inhalation cancer risks (ECR) due to human exposure to PAHs during winter and summer sampling periods were 45–3540 cancer cases and 31–2451 cases per million people, respectively. The average ECR in the industrial area of Lanzhou valley was 1.97 (winter) and 1.88 times (summer) higher than that in other sampling areas. The higher ECR in the industrial area was resulted primarily by industrial activities and insufficient emission control measures. Extracts from passive air samples in genotoxicity SOS/umu test demonstrated that the genotoxic effect of atmospheric PAHs in Lanzhou was seasonal dependent. PAH air samples collected in winter showed more statistically significant genotoxicity, as manifested by a strong correlation between in vitro genotoxicity and atmospheric PAH concentrations. This indicates that the local residents were under higher potential cancer risk through the inhalation of ambient PAH air concentrations in Lanzhou valley during the wintertime.
Afficher plus [+] Moins [-]Characteristic comparison of heavy metal contamination between road-deposited and roof-deposited sediments in suburban area
2017
Yu, Jianghua | Yu, Haixia | Xu, Liqiang | Tao, Tao | Zhang, Yanxing | Hua, Yuhao | Nkolola, Namwiinga Babra
Surface-deposited sediment in urban area is an essential environmental medium for assessing heavy metal contamination. A total of 10 sampling trips were conducted to collect road-deposited and roof-deposited sediments for the comparison of nickel (Ni), copper (Cu), cadmium (Cd), lead (Pb), zinc (Zn), and chromium (Cr) contamination characteristics. Results indicated that roof sediment appeared to have a finer size distribution than road sediments. Roof sediment indicated higher metal concentration and lower surface loading than road sediment. The impact of particle size on heavy metal contamination was quantified by using the developed pioneering term of finer particle effect factor; it differed according to surface types and grain size fraction. Particles in individual grain size fraction showed different contribution to the surface loading for bulk sediments. No consistent trend was found for the grain size fraction loading along with grain size for the studied heavy metals for road sediments. In contrast, an asymmetric “W” trend was observed for the roof sediments, and it had the following results: Fraction of <63 and 250–500 μm showed higher loading, while fraction of 90–125 and >850 μm indicated the smaller loading. Findings above facilitated the appropriate management practice selection for the treatment of surface-deposited sediments.
Afficher plus [+] Moins [-]The influence of growth form and substrate on lichen ecophysiological responses along an aridity gradient
2017
Paoli, Luca | Pinho, Pedro | Branquinho, Cristina | Loppi, Stefano | Munzi, Silvana
In this paper, we investigated whether growth form and substrate in lichens influence their physiological responses along an aridity gradient. Thalli of the foliose lichen Parmotrema perlatum and the fruticose lichen Ramalina canariensis were transplanted in selected rural/forested sites of Southern Portugal characterized by a different aridity index. Physiological parameters including photosynthetic performances, assimilation pigments, ergosterol content and sample viability were measured prior to exposure (winter) and after 6-month exposure (summer). Photosynthetic performances were also investigated in common native foliose and fruticose epiphytic lichens and in fruticose terricolous species. Both transplanted and native lichens showed a decrease in photosynthetic performances in summer and lower performances in sites classified as drier and higher performances in humid forested sites. No relevant differences occurred between epiphytic foliose and fruticose growth forms. However, terricolous fruticose samples showed a significant difference in humid and drier sites and between winter and summer, probably due to microclimatic conditions similarly to other biological crusts.
Afficher plus [+] Moins [-]Investigation of heavy metal pollution in eastern Aegean Sea coastal waters by using Cystoseira barbata, Patella caerulea, and Liza aurata as biological indicators
2017
Aydın-Önen, S. | Öztürk, M.
In order to have an extensive contamination profile of heavy metal levels (Cd, Cu, Fe, Mn, Ni, Pb, and Zn), seawater, sediment, Patella caerulea, Cystoseira barbata, and Liza aurata were investigated by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Samples were collected from five coastal stations along the eastern Aegean Sea coast (Turkey) on a monthly basis from July 2002 through May 2003. According to the results of this study, heavy metal levels were arranged in the following sequence: Fe > Pb > Zn > Mn > Ni > Cu > Cd for water, Fe > Cu > Mn > Ni > Zn > Pb > Cd for sediment, Fe > Zn > Mn > Pb > Ni > Cd > Cu for C. barbata, Fe > Zn > Mn > Ni > Pb > Cu > Cd for P. caerulea, and Fe > Zn > Mn > Cu > Ni > Pb > Cd for L. aurata. Moreover, positive relationships between Fe in water and Mn in water, Fe in sediment and Mn in sediment, Fe in C. barbata and Mn in C. barbata, Fe in P. caerulea and Mn in P. caerulea, and Fe in L. aurata and Mn in L. aurata may suggest that these metals could be originated from the same anthropogenic source. C. barbata represented with higher bioconcentration factor (BCF) values, especially for Fe, Mn, and Zn values. This observation may support that C. barbata can be used as an indicator species for the determinations of Fe, Mn, and Zn levels. Regarding Turkish Food Codex Regulation’s residue limits, metal values in L. aurata were found to be lower than the maximum permissible levels issued by Turkish legislation and also the recommended limits set by FAO/WHO guidelines. The results of the investigation indicated that P. caerulea, L. aurata, and especially C. barbata are quantitative water-quality bioindicators and biomonitoring subjects for biologically available metal accumulation for Aegean Sea coastal waters.
Afficher plus [+] Moins [-]Titanium dioxide-based sonophotocatalytic mineralization of bisphenol A and its intermediates
2017
Sunasee, Sharmini | Wong, Kien Tiek | Lee, Gooyong | Pichiah, Saravanan | Ibrahim, Shaliza | Park, Chulhwan | Kim, Nam Chan | Yoon, Yeomin | Jang, Min
In this study, bisphenol A (BPA) removal by sonophotocatalysis coupled with commercially available titanium dioxide (TiO₂, P25) was assessed in batch tests using energy-based advanced oxidation combining ultrasound (US) and ultraviolet (UV). The kinetics of BPA removal were systematically evaluated by changing operational parameters, such as US frequency and power, mechanical stirring speed, and temperature, but also comparison of single and coupled systems under the optimum US conditions (35 kHz, 50 W, 300 rpm stirring speed, and 20 °C). The combination of US/UV/P25 exhibited the highest BPA removal rate (28.0 × 10⁻³ min⁻¹). In terms of the synergy index, the synergistic effect of sonophotocatalysis was found to be 2.2. This indicated that sonophotocatalysis has a considerably higher removal efficiency than sonocatalysis or photocatalysis. The removal of BPA was further investigated to identify BPA byproducts and intermediates using high-performance liquid chromatography–mass spectrometry. Five main intermediates were formed during sonophotocatalytic degradation, and complete removal of BPA and its intermediates was obtained after 3 h of operation. The degradation pathway of BPA by sonophotocatalysis was also elucidated.
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