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Devrim Kaya, Ipek Imamoglu, F Dilek Sanin, Rayford B Payne, Kevin R Sowers
Aroclor 1254 was the second most produced commercial PCB mixture and is found in soils, sediments and sewage throughout the globe. This commercial PCB mixture is considered particularly toxic because of the relatively high concentrations of congeners with dioxin-like properties. The potential for risk reduction by microbial reductive dechlorination of Aroclor 1254 (A1254) was investigated in sediment microcosms from Grasse River (GR), Massena, NY. The specificity of A1254 dechlorination was doubly- and singly-flanked chlorines in meta positions and to a less extent doubly-flanked para chlorines of 2345-substituted chlorobiphenyl rings...
October 5, 2016: Journal of Hazardous Materials
Cancan Xu, Rui Liu, Lvjun Chen, Jialu Tang
Ni/Fe-Fe3O4 nanocomposites were synthesized for dechlorination of 2,4-dichlorophenol (2,4-DCP). The effects of the Ni content in Ni/Fe-Fe3O4 nanocomposites, solution pH, and common dissolved ions on the dechlorination efficiency were investigated, in addition to the reusability of the nanocomposites. The results showed that increasing content of Ni in Ni/Fe-Fe3O4 nanocomposites, from 1 to 5wt.%, greatly increased the dechlorination efficiency; the Ni/Fe-Fe3O4 nanocomposites had much higher dechlorination efficiency than bare Ni/Fe nanoparticles...
October 2016: Journal of Environmental Sciences (China)
Shizong Wang, Yanan Yin, Jianlong Wang
Triclosan is an antimicrobial agent which has been frequently detected in the environment. In this paper, the biodegradation of triclosan after radiation-induced advanced oxidation was investigated. The results show that the removal efficiency of triclosan in the combined irradiation and biological treatment process ranged from 88% to 97%, depending on the absorbed dose, while it was only 54% in the single biological treatment process. The removal efficiency of total organic carbon (TOC) was in the range of 53...
October 13, 2016: Chemosphere
Ying Lan, Andrew S Elwood Madden, Elizabeth C Butler
Trichloroethylene (TCE) and tetrachloroethylene (PCE) are common ground water contaminants susceptible to reductive dechlorination by FeS (mackinawite) in anaerobic environments. The objective of this study was to characterize the mineral-associated products that form when mackinawite reacts with TCE and PCE. The dissolved products of the reaction included Cl(-) and Fe(2+), and trace amounts of cis 1,2-dichloroethylene (for TCE) and TCE (for PCE). Selected area electron diffraction (SAED) analysis identified greigite as a mackinawite oxidation product formed after reaction between TCE or PCE and FeS over seven weeks...
October 12, 2016: Environmental Science. Processes & Impacts
Guangping Fan, Yu Wang, Guodong Fang, Xiangdong Zhu, Dongmei Zhou
Polychlorinated biphenyls (PCBs) are manmade organic compounds, and pollution due to PCBs has been a global environmental problem because of their persistence, long-range atmospheric transport and bioaccumulation. Many physical, chemical and biological technologies have been utilized to remediate PCBs contaminated soils and sediments, and there are some emerging new technologies and combined methods that may provide cost-effective alternatives to the existing remediation practice. This review provides a general overview on the recent developments in chemical treatment and electrokinetic remediation (EK) technologies related to PCBs remediation...
September 14, 2016: Environmental Science. Processes & Impacts
Bruna Matturro, Carla Ubaldi, Simona Rossetti
The toxicity of polychlorinated biphenyls (PCB) can be efficiently reduced in contaminated marine sediments through the reductive dechlorination (RD) process lead by anaerobic organohalide bacteria. Although the process has been extensively investigated on PCB-spiked sediments, the knowledge on the identity and metabolic potential of PCB-dechlorinating microorganisms in real contaminated matrix is still limited. Aim of this study was to explore the composition and the dynamics of the microbial communities of the marine sediment collected from one of the largest Sites of National Interest (SIN) in Italy (Mar Piccolo, Taranto) under conditions promoting the PCBs RD...
2016: Frontiers in Microbiology
Amel M Garbou, Christian A Clausen, Cherie L Yestrebsky
Chlorophenols are highly toxic, environmentally-persistent compounds which have been classified as probable human carcinogens by the United States Environmental Protection Agency. Due to the high toxicity of these compounds, it is necessary to treat water and soils with concentrations of chlorophenols above the detection limit set by regulatory agencies. The aim of this work is to demonstrate the capabilities of using ball-milled magnesium for the dechlorination of PCP. Comparison of dechlorination processes were performed in an attempt to determine the most effective system for degradation of PCP to phenol...
January 2017: Chemosphere
Charlotte J Sparrenbom, Sofia Åkesson, Sara Johansson, David Hagerberg, Torleif Dahlin
Globally, an enormous number of polluted areas are in need of remediation to prevent adverse effects on health and environment. In situ remediation and especially the monitoring thereof needs further development to avoid costly and hazardous shipments associated with excavation. The monitoring of in situ remediation actions needs easier and cheaper nondestructive methods for evaluation and verification of remediation degree and degradation status of the contaminants. We investigate the Direct Current resistivity and time-domain Induced Polarization tomography (DCIP) method and its use within the context of a DNAPL (Dense Non-Aqueous Phase Liquids) contaminated site in Varberg, Sweden, where an in situ remediation pilot test has been performed by stimulated reductive dechlorination by push injection...
September 30, 2016: Science of the Total Environment
Kevin S Jewell, Per Falås, Arne Wick, Adriano Joss, Thomas A Ternes
The biotransformation of diclofenac during wastewater treatment was investigated. Attached growth biomass from a carrier-filled compartment of a hybrid-MBBR at the wastewater treatment plant (WWTP) in Bad Ragaz, Switzerland was used to test the biotransformation. Laboratory-scale incubation experiments were performed with diclofenac and carriers and high-resolution LC-QTof-MS was implemented to monitor the biotransformation. Up to 20 diclofenac transformation products (TPs) were detected. Tentative structures were proposed for 16 of the TPs after characterization by MS(2) fragmentation and/or inferring the structure from the transformation pathway and the molecular formula given by the high resolution ionic mass...
November 15, 2016: Water Research
Shengkun Dong, Jinfeng Lu, Michael J Plewa, Thanh H Nguyen
Reusing wastewater in agriculture is becoming increasingly common, which necessitates disinfection to ensure reuse safety. However, disinfectants can react with wastewater constituents to form disinfection byproducts (DBPs), many of which are toxic and restrict the goal of safe reuse. Our objective was to benchmark the induction of mammalian cell cytotoxicity after ozonation against chlorination for three types of real wastewaters: municipal secondary effluent and two sources of minimally-treated swine farm wastewaters...
September 30, 2016: Environmental Science & Technology
Nobumitsu Sakai, Emmy Dayana, Azizi Abu Bakar, Minoru Yoneda, Nik Meriam Nik Sulaiman, Mustafa Ali Mohd
Polychlorinated biphenyls (PCBs) were monitored in surface water collected in the Selangor River basin, Malaysia, to identify the occurrence, distribution, and dechlorination process as well as to assess the potential adverse effects to the Malaysian population. Ten PCB homologs (i.e., mono-CBs to deca-CBs) were quantitated by using gas chromatography-mass spectrometry (GC/MS). The total concentration of PCBs in the 10 sampling sites ranged from limit of detection to 7.67 ng L(-1). The higher chlorinated biphenyls (tetra-CBs to deca-CBs) were almost not detected in most of the sampling sites, whereas lower chlorinated biphenyls (mono-CBs, di-CBs, and tri-CBs) dominated more than 90 % of the 10 homologs in all the sampling sites...
October 2016: Environmental Monitoring and Assessment
Pierre Benoit, Laure Mamy, Rémi Servien, Ziang Li, Eric Latrille, Virginie Rossard, Fabienne Bessac, Dominique Patureau, Fabrice Martin-Laurent
Chlordecone (C10Cl10O; CAS number 143-50-0) has been used extensively as an organochlorine insecticide but is nowadays banned and listed on annex A in The Stockholm Convention on Persistent Organic Pollutants (POPs). Although experimental evidences of biodegradation of this compound are scarce, several dechlorination products have been proposed by Dolfing et al. (2012) using Gibbs free energy calculations to explore different potential transformation routes. We here present the results of an in silico classification (TyPol - Typology of Pollutants) of chlordecone transformation products (TPs) based on statistical analyses combining several environmental endpoints and structural molecular descriptors...
September 21, 2016: Science of the Total Environment
Hui Yun, Deyong Kong, Bin Liang, Minhua Cui, Zhiling Li, Aijie Wang
Chloramphenicol (CAP) is a frequently detected environmental pollutant. In this study, an electroactive biofilm for CAP reduction was established by initially in the anode and then inverting to the cathode. The established biocathode could enhance the reduction of CAP to the nitro-group reduced CAP (AMCl2) and further dechlorinated form (AMCl), both had lost the antibacterial activity. The phylogenetic diversity of the acclimated biofilm was decreased after the polar inversion. Proportions of functional bacterial genera, including Geobacter, Desulfovibrio and Pseudomonas responsible for the bidirectional electron transfer and nitroaromatics reduction, had increased 28%, 104% and 43% in the cathode...
December 2016: Bioresource Technology
Siavash Atashgahi, Yue Lu, Ying Zheng, Edoardo Saccenti, Maria Suarez-Diez, Javier Ramiro-Garcia, Heinrich Eisenmann, Martin Elsner, Alfons J M Stams, Dirk Springael, Winnie Dejonghe, Hauke Smidt
Biostimulation is widely used to enhance reductive dechlorination of chlorinated ethenes in contaminated aquifers. However, the knowledge on corresponding biogeochemical responses is limited. In this study, glycerol was injected in an aquifer contaminated with cis-dichloroethene (cDCE), and geochemical and microbial shifts were followed for 265 days. Consistent with anoxic conditions and sulfate reduction after biostimulation, MiSeq 16S rRNA gene sequencing revealed temporarily increased relative abundance of Firmicutes, Bacteriodetes and sulfate reducing Deltaproteobacteria...
October 6, 2016: Environmental Microbiology
Christophe Mouvet, Marie-Christine Dictor, Sébastien Bristeau, Dominique Breeze, Anne Mercier
Chlordecone (CLD), a highly persistent organochlorine pesticide commonly encountered in French West Indies (FWI) agricultural soils, represents a major source of contamination of FWI ecosystems. The potential of chemical reduction for remediation of CLD-contaminated soil has been investigated in laboratory pilot-scale 80 kg mesocosms for andosol, ferralsol, and nitisol from FWI banana plantations. Six cycles consisting of a 3-week reducing phase followed by a 1-week oxidizing phase were applied, with 2 % (dw/dw) Daramend® (organic plant matter fortified with zero valent iron) added at the start of each cycle...
September 15, 2016: Environmental Science and Pollution Research International
Abhay Bajaj, Anand Kumar, Shivani Yadav, Gurwinder Kaur, Monu Bala, Nitin Kumar Singh, Rajendran Mathan Kumar, Natesan Manickam, Shanmugam Mayilraj
The taxonomic position of a Gram-stain-negative, non-violacein pigmented bacterium isolated from an insecticide contaminated site was characterized by a polyphasic approach. The bacterium was able to grow on three different halogenated compounds namely 1-Chlorobutane, 1-Chloropropane and 1, 2-Dichlorethane. As a critical step in the degradation of these haloalkanes, stoichiometric amounts of dechlorination were estimated. Based on selective enrichment method for three months, using a highly contaminated mixed chemical soil, a bacterium was obtained and designated as IITR-71T...
September 11, 2016: International Journal of Systematic and Evolutionary Microbiology
Zhenzhen Huang, Guiqiu Chen, Guangming Zeng, Zhi Guo, Kai He, Liang Hu, Jing Wu, Lihua Zhang, Yuan Zhu, Zhongxian Song
Mechanisms of silver nanoparticles-mediated toxicity to Phanerochaete chrysosporium and the influence of silver nanoparticles (AgNPs) on the biodegradation of 2,4-dichlorophenol (2,4-DCP) have been systematically investigated. AgNPs at low doses (0-60μM) have greatly enhanced the degradation ability of P. chrysosporium to 2,4-DCP with the maximum degradation rates of more than 94%, exhibiting excellent synergies between AgNPs and P. chrysosporium in the degradation of 2,4-DCP. Meanwhile, removal of total Ag was also at high levels and highly pH dependent...
August 31, 2016: Journal of Hazardous Materials
Qiongmin Cao, Guoan Yuan, Lijie Yin, Dezhen Chen, Pinjing He, Hai Wang
In this research morphological techniques were used to characterize dechlorination process of PVC when it is in the mixed waste plastics and the two important factors influencing this process, namely, the proportion of PVC in the mixed plastics and heating rate adopted in the pyrolysis process were investigated. During the pyrolysis process for the mixed plastics containing PVC, the morphologic characteristics describing PVC dechlorination behaviors were obtained with help of a high-speed infrared camera and image processing tools...
September 2, 2016: Waste Management
Wei Zhang, Tian Yu, Xiaolin Han, Weichi Ying
We explored the feasibility and removal mechanism of removing 2-chlorobiphenyl (2-ClBP) from soil-water system using granular activated carbon (GAC) impregnated with nanoscale zerovalent iron (reactive activated carbon or RAC). The RAC samples were successfully synthesized by the liquid precipitation method. The mesoporous GAC based RAC with low iron content (1.32%) exhibited higher 2-ClBP removal efficiency (54.6%) in the water phase. The result of Langmuir-Hinshelwood kinetic model implied that the different molecular structures between 2-ClBP and trichloroethylene (TCE) resulted in more difference in dechlorination reaction rates on RAC than adsorption capacities...
September 2016: Journal of Environmental Sciences (China)
Kaelyn Gras, Jim Luong, Ronda Gras, Robert A Shellie
A headspace gas chromatographic approach based on flame ionization detection has been successfully developed for the determination of parts-per-billion levels of 2,4-dichlorophenol and 2,6-dichlorophenol in processed dairy milk. Under the right environmental conditions, these compounds are produced as products of the reductive dechlorination of pentachlorophenol. Maintaining a highly inert chromatographic system and employing a recently commercialized inert capillary column permits the analysis of 2,4-dichlorophenol and 2,6-dichlorophenol without derivatization...
October 2016: Journal of Separation Science
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