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Sebastian Kucher, Larissa Dsikowitzky, Mathias Ricking, Sujatha C H, Jan Schwarzbauer
The pesticide DDT (1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene) and its degradates are among the most persistent and abundant organochlorine contaminates in the environment, and DDT is still being produced in several Asian countries. In this study, we report for the first time on the detection of DDT-related compounds with one additional or missing chlorine atom at the phenyl group (DDX±Cl ) in sediment and soil samples taken in the vicinity of former and current DDT production sites. These congeneric compounds most likely originate from production residues disposed of into the environment...
April 11, 2018: Journal of Hazardous Materials
Guiying Li, Huan Yang, Taicheng An, Yujuan Lu
Safe drinking water is essential for the wellbeing of people around the world. In this work, the occurrence, distribution, and elimination of four groups of antibiotics including fluoroquinolones, sulfonamides, chloramphenicols and macrolides (21 antibiotics total), were studied in two drinking water treatment plants during the wet and dry seasons. In the drinking water source (river), the most abundant group was fluoroquinolones. In contrast, chloramphenicols were all under the limitation of detection. Total concentration of all investigated antibiotics was higher in dissolved phase (62-3...
April 20, 2018: Ecotoxicology and Environmental Safety
P Diogo, M Mota, C Fernandes, D Sequeira, P Palma, F Caramelo, M G P M S Neves, M A F Faustino, T Gonçalves, J M Santos
BACKGROUND: The aim of this study was to assess antimicrobial efficacy and cytotoxic outcomes of a chlorophyll based photosensitizer (PS) Zn(II)chlorin e6 methyl ester (Zn(II)e6 Me), when applied to human dentin discs and root blocks infected with 48 h biofilms. The results were compared with the ones obtained with FotoSan® (commercial Toluidine Blue O formulation) and 3% sodium hypochlorite (NaOCl). METHODOLOGY: Dentin and root blocks were infected with mixed biofilms of Enterococcus faecalis and Candida albicans; exposed for 15 min to 0...
April 20, 2018: Photodiagnosis and Photodynamic Therapy
Tongxu Gu, Liang Cheng, Fei Gong, Jun Xu, Xiang Li, Gaorong Han, Zhuang Liu
The efficacy of conventional photodynamic therapy (PDT) is markedly suppressed by limited penetration depth of light in biological tissues and oxygen depletion in the hypoxic tumor microenvironment. Herein, mesoporous silica nanospheres with fine CaF2: Yb, Er upconversion nanocrystals entrapped in their porous structure are synthesized via a thermal decomposition method. After subsequently coating with a thin MnO2 layer and loading with a photosensitizer, Chlorin e6 (Ce6), a new type of nanoscale PDT platform is obtained...
April 23, 2018: ACS Applied Materials & Interfaces
Jeffrey Szabo, John Hall, Steve Reese, Jim Goodrich, Sri Panguluri, Greg Meiners, Hiba Ernst
The EPA's Water Security Test Bed (WSTB) facility is a full-scale representation of a drinking water distribution system. In collaboration with the Idaho National Laboratory (INL), EPA designed the WSTB facility to support full-scale evaluations of water infrastructure decontamination, real-time sensors, mobile water treatment systems, and decontamination of premise plumbing and appliances. The EPA research focused on decontamination of 1) Bacillus globigii (BG) spores, a non-pathogenic surrogate for Bacillus anthracis and 2) Bakken crude oil...
March 20, 2018: Journal—American Water Works Association
Kevin Tyan, Katherine Jin, Jason Kang, Aaron M Kyle
Bleach sprays suffer from poor surface coverage, dry out before reaching proper contact time, and can be inadvertently over-diluted to ineffective concentrations. Highlight® , a novel color additive for bleach that fades to indicate elapsed contact time, maintained >99.9% surface coverage over full contact time and checked for correct chlorine concentration.
April 18, 2018: American Journal of Infection Control
Karen E Setty, Jerome Enault, Jean-Francois Loret, Claudia Puigdomenech Serra, Jordi Martin-Alonso, Jamie Bartram
Water Safety Plans (WSPs), recommended by the World Health Organization since 2004, can help drinking water suppliers to proactively identify potential risks and implement preventive barriers that improve safety. Few studies have investigated long-term impacts of WSPs, such as changes in drinking water quality or public health; however, some evidence from high-income countries associates WSP implementation with a reduction in diarrheal disease. To validate the previously observed linkages between WSPs and health outcomes, this time series study examined site-specific relationships between water-related exposures and acute gastroenteritis rates at three locations in France and Spain, including the role of WSP status...
April 6, 2018: International Journal of Hygiene and Environmental Health
Sukhbayar Gankhuyag, Kyoung Lee, Dong Sik Bae
We have suggested that a facile synthesis of CoFe2O4/Ag composite material as an antibacterial agent for substitution of a chlorination agent for microbial infected wastewater treatment. The CoFe2O4/Ag was synthesized by an impregnation method in assistance with trisodium citrate as a reducing agent. The as-prepared uncalcined CoFe2O4 (CFG), calcined CoFe2O4 (CFG600), and calcined CoFe2O4/Ag (CFG600/Ag) composites were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM) and Energy Dispersive X-ray (EDX) techniques...
September 1, 2018: Journal of Nanoscience and Nanotechnology
Tatiana Prado, Antônio de Castro Bruni, Mikaela Renata Funada Barbosa, Vilma Marques Santos Bonanno, Suzi Cristina Garcia, Maria Inês Zanoli Sato
Bacteriophages infecting Bacteroides fragilis GB-124 have been described as potential markers of human fecal contamination in water sources. The aim of this study was to evaluate the occurrence of GB-124 phages in raw sewage, secondary effluents and reclaimed water of the São Paulo city using a low-cost microbial source tracking method. Samples were collected monthly from April 2015 to March 2016 in four municipal wastewater treatment plants that operate with activated sludge processes followed by different tertiary treatments (sand-anthracite filtration, membrane bioreactor/reverse osmosis) and final chlorination...
April 2018: Journal of Water and Health
Anu Rajasingham, Margaret Leso, Samuel Ombeki, Tracy Ayers, Robert Quick
Many health care facilities (HCFs) and households in low-and-middle-income countries have inadequate access to water for hygiene and consumption. To address these problems, handwashing and drinking water stations were installed in 53 HCFs with prevention-of-mother-to-child-transmission of HIV programs in Kenya in 2005, and hygiene education was provided to health workers and clinic clients. To assess this program, we selected a random sample of 30 HCFs, observed the percentage of handwashing and drinking water stations that were functional and in use, and after that interviewed health providers and clients about hygiene and water treatment...
April 2018: Journal of Water and Health
Marjolein C F M Peters, Maarten G A Keuten, Aleksandra Knezev, Mark C M van Loosdrecht, Johannes S Vrouwenvelder, Luuk C Rietveld, Merle K de Kreuk
Bathers release bacteria in swimming pool water, but little is known about the fate of these bacteria and potential risks they might cause. Therefore, shower water was characterized and subjected to chlorination to identify the more chlorine-resistant bacteria that might survive in a chlorinated swimming pool and therefore could form a potential health risk. The total community before and after chlorination (1 mg Cl2 L-1 for 30 s) was characterized. More than 99% of the bacteria in the shower water were Gram-negative...
April 2018: Journal of Water and Health
Alexander Spina, David Beversluis, Andrea Irwin, Alexandra Chen, Jean Noel Nassariman, Abdelkhadir Ahamat, Idriss Noh, Jan Oosterloo, Prince Alfani, Sibylle Sang, Annick Lenglet, Dawn Louise Taylor
In September 2016, Médecins Sans Frontières responded to a hepatitis E (HEV) outbreak in Chad by implementing water treatment and hygiene interventions. To evaluate the coverage and use of these interventions, we conducted a cross-sectional study in the community. Our results showed that 99% of households interviewed had received a hygiene kit from us, aimed at improving water handling practice and personal hygiene and almost all respondents had heard messages about preventing jaundice and handwashing. Acceptance of chlorination of drinking water was also very high, although at the time of interview, we were only able to measure a safe free residual chlorine level (free chlorine residual (FRC) ≥0...
April 2018: Journal of Water and Health
Buddhika Gunawardana, Peter J Swedlund, Naresh Singhal, Michel K Nieuwoudt
The dechlorination of chlorinated organic pollutants by zero valent iron (ZVI) is an important water treatment process with a complex dependence on many variables. This complexity means that there are reported inconsistencies in terms of dechlorination with ZVI and the effect of ZVI acid treatment, which are significant and are as yet unexplained. This study aims to decipher some of this complexity by combining Raman spectroscopy with gas chromatography-mass spectrometry (GC-MS) to investigate the influence of the mineralogy of the iron oxide phases on the surface of ZVI on the reductive dechlorination of pentachlorophenol (PCP)...
April 20, 2018: Environmental Science and Pollution Research International
Matthias Kotthoff, Mark Bücking
Per- and polyfluoroalkyl substances (PFAS) represent a versatile group of ubiquitously occurring chemicals of increasing regulatory concern. The past years lead to an ever expanding portfolio of detected anthropogenic PFAS in numerous products encountered in daily life. Yet no clear picture of the full range of individual substance that comprise PFAS is available and this challenges analytical and engineering sciences. Authorities struggle to cope with uncertainties in managing risk of harm posed by PFAS. This is a result of an incomplete understanding of the range of compounds that they comprise in differing products...
2018: Frontiers in Chemistry
Jie Li, Chunyang Sun, Wei Tao, Ziyang Cao, Haisheng Qian, Xianzhu Yang, Jun Wang
Controlling poly(ethylene glycol) (PEG) shielding/deshielding at the desired site of action exhibits great advantages for nanocarrier-based on-demand drug delivery in vivo. However, the current PEG deshielding strategies were mainly designed for anticancer drug delivery; even so, their applications are also limited by tumor heterogeneity. As a proof-of-concept, we explored a photoinduced PEG deshielding nanocarrier TK-NPCe6&PTX to circumvent the aforementioned challenge. The TK-NPCe6&PTX encapsulating chlorin e6 (Ce6) and paclitaxel (PTX) was self-assembled from an innovative thioketal (TK) linkage-bridged diblock copolymer of PEG with poly(d,l-lactic acid) (PEG-TK-PLA)...
April 10, 2018: Biomaterials
Hong Zhang, Qifu Zhang, Chunguang Miao, Qing Huang
Chlorinated phenols are a class of contaminants found in water and have been regarded as a great potential risk to environment and human health. It is thus urgent to develop effective techniques to remove chlorinated phenols in wastewater. For this purpose, we employed dielectric barrier discharge (DBD) in this work and studied the efficiency of DBD for the degradation of 2,4-dichlorophenol (2,4-DCP), one of the most typical chlorophenols in the environment. The effects of pH value, applied voltage and plasma-working gases on the dichlorophenol-removal efficiency were investigated...
April 11, 2018: Chemosphere
Sonja Srdanović, Ying-Hua Gao, Dan-Ye Chen, Yi-Jia Yan, Davor Margetić, Zhi-Long Chen
A novel 131 -pyridine substituted chlorin e6 derivative (Chlorin A) was synthesized. It has characteristic long wavelength absorption at 664 nm and the emission wavelength at 667 nm. The generation rate of singlet oxygen of this compound is higher than Temoporfin. In vitro, Chlorin A showed higher phototoxicity against the human esophageal cancer cells than Temoporfin while with lower dark-toxicity. Its accumulation effect in mitochondria, lysosomes and endoplasmic reticulum was traced in subcellular localization tests...
April 12, 2018: Bioorganic & Medicinal Chemistry Letters
Sarah Potgieter, Ameet Pinto, Makhosazana Sigudu, Hein du Preez, Esper Ncube, Stephanus Venter
Long-term spatial-temporal investigations of microbial dynamics in full-scale drinking water distribution systems are scarce. These investigations can reveal the process, infrastructure, and environmental factors that influence the microbial community, offering opportunities to re-think microbial management in drinking water systems. Often, these insights are missed or are unreliable in short-term studies, which are impacted by stochastic variabilities inherent to large full-scale systems. In this two-year study, we investigated the spatial and temporal dynamics of the microbial community in a large, full scale South African drinking water distribution system that uses three successive disinfection strategies (i...
March 30, 2018: Water Research
Rania Nassar, Ahmad Rifai, Aurélien Trivella, Patrick Mazellier, Samia Mokh, Mohamad Al-Iskandarani
Sulfonamides (SNs) are synthetic antimicrobial agents. These substances are continually introduced into the environment and they may spread and maintain bacterial resistance in the different compartments. The chlorination of two sulfonamides, namely sulfamethazine (SMT) and sulfamethoxypyridazine (SMP), was investigated in order to study their reactivity with chlorine at typical concentrations for water treatment conditions. Experiments conducted in purified water show an acceleration of SMT and SMP degradation of a factor 1...
April 19, 2018: Journal of Mass Spectrometry: JMS
Claudio A Álvarez, Paula A Santana, Omar Luna, Constanza Cárdenas, Fernando Albericio, María S Romero, Fanny Guzmán
Cyclotides are circular peptides found in various plant families. A cyclized backbone, together with multiple disulfide bonds, confers the peptides’ exceptional stability against protease digestion and thermal denaturation. In addition, the features of these antimicrobial molecules make them suitable for use in animal farming, such as aquaculture. Fmoc solid phase peptide synthesis on 2-chlorotrityl chlorine (CTC) resin using the “tea-bag” approach was conducted to generate the VarvA cyclotide identified previously from Viola arvensis ...
April 19, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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