Effect and mechanism analysis of MnO2 on permeable reactive barrier (PRB) system for the removal of tetracycline Chemosphere (IF 4.208) Pub Date : 2017-11-17 Guihua Dong, Lihui Huang, Xueyuan Wu, Chuang Wang, Yangyang Liu, Gaofeng Liu, Lisha Wang, Xiaowei Liu, Haibing Xia
Effect of manganese dioxide (MnO2) on tetracycline (TC) removal/degradation in zero-valent iron (ZVI) based permeable reactive barrier (PRB) system was investigated. To analyze the role of MnO2, three different PRB columns packed with ZVI, ZVI and a layer of MnO2, and MnO2 were set up to investigate the removal effect and reaction mechanism of ZVI coupling with MnO2 on TC removal, respectively. The results show that the removal efficiencies of three PRB columns are 65%, 85%, and 50%, respectively. MnO2 could accelerate the transformation of Fe2+ into Fe3+ and combine with Fe3+ to degrade TC in different reaction sites in the ZVI-MnO2 PRB system. Hydroxyl radicals (·OH) were produced in this process, which contributed to about 58.3% for the TC degradation. The UV–Vis spectrum demonstrated that A ring of TC was the main reaction site for interaction with Fe3+ and the BCD rings were crucial for interactions with MnO2. On the basis of intermediates identified by LC-ESI-MS, the ring structure of TC was opened, and low-molecular-weight compounds were produced in ZVI-MnO2 PRB system.
Revitalisation of metal-contaminated, EDTA-washed soil by addition of unpolluted soil, compost and biochar: Effects on soil enzyme activity, microbial community composition and abundance Chemosphere (IF 4.208) Pub Date : 2017-11-17 Anela Kaurin, Zarja Cernilogar, Domen Lestan
Soil remediation mitigates hazards from contaminants but could deprive soils of initial biota and enzymes. Historically contaminated acidic soil from Arnoldstein (Austria) and calcareous soil from Meza (Slovenia) were washed with 30 and 100 mmol kg−1 ethylenediaminetetraacetate (EDTA) to remove 78 and 60% of Pb as a main pollutant. Remediation of the Arnoldstein soil decreased urease activity and increased β-glucosidase activity, measured in a 15-week experiment. The dehydrogenase activity and microbial gene abundances were not significantly impeded compared to the original soil. Conversely, the use of a high dose of EDTA in the Meza soil, necessary for effective remediation of calcareous soils, resulted in pronouncedly decreased enzyme activities (3.2 times on average) and repressed fungal ITS and increased bacterial 16S rRNA gene abundance. Remediation shifted the microbial community composition in both soils. For revitalisation, the remediated soils were amended with compost, inocula of un-contaminated soil and (Arnoldstein soil) biochar enriched with soil extract. Amendments inconsistently affected the Arnoldstein soil: compost increased the dehydrogenase activity and altered the microbial community composition, biochar enhanced the β-glucosidase activity, and all amendments decreased the microbial abundance (1.6 times on average). In contrast, amendments efficiently revitalised the remediated Meza soil; compost and soil inoculum returned the enzyme activities back to the baseline in the original soil, increased the fungal abundance above that in the original soil and restored the microbial community composition.
Comparative evaluation of sorption kinetics and isotherms of pyrene onto microplastics Chemosphere (IF 4.208) Pub Date : 2017-11-17 Wenfeng Wang, Jun Wang
Concerns regarding microplastics pollution and their potential to concentrate and transport organic contaminants in aquatic environments are growing in recent years. Sorption of organic chemicals by microplastics may affect the distribution and bioavailability of the chemicals. Here sorption process of pyrene (Pyr), a frequently encountered polycyclic aromatic hydrocarbon in aquatic environments, on three types of mass-produced plastic particles (high-density polyethylene (PE), polystyrene (PS) and polyvinylchloride (PVC)), was investigated by comparative analysis of different sorption kinetic and isotherm models. Optimum kinetic and isotherm models were predicted by the linear least-squares regression method. The pseudo-second-order kinetic model was more appropriate in describing the entire sorption process (R2 > 0.99). Sorption rates of Pyr onto microplastics were mainly controlled by intraparticle diffusion. PE exhibited the highest affinity for Pyr, followed by PS and PVC. The sorption equilibrium data were best fitted to the Langmuir isotherm (R2 > 0.99), indicating monolayer coverage of Pyr onto the microplastics.
Toxic effects and mechanism of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on Lemna minor Chemosphere (IF 4.208) Pub Date : 2017-11-17 Nianwei Qiu, Renjun Wang, Yuan Sun, Xiushun Wang, Dacheng Jiang, Yuting Meng, Feng Zhou
To investigate the toxic effect and mechanism of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in aquatic plants, in vivo and in vitro exposure to BDE-47 were conducted. After 14-d exposure to 5–20 μg/L BDE-47, the growth of Lemna minor plants was significantly suppressed, and the chlorophyll and soluble protein contents in fronds markedly decreased. Accordingly, the photosynthetic efficiency (Fv/Fm, PI) decreased. When the thylakoid membranes isolated from healthy fronds was exposed to 5–20 mg/L BDE-47 directly in vitro for 1 h, the photosynthetic efficiency also decreased significantly. In both the in vitro (5–20 μg/L) and in vivo (5–20 mg/L) experiments, BDE-47 led to an increased plasma membrane permeability. Hence, we concluded that BDE-47 had a direct toxicity to photosynthetic membranes and plasma membranes. However, direct effects on the activities of peroxidase (POD), malate dehydrogenase (MDH) and nitroreductase (NR) were not observed by adding 5–20 mg/L BDE-47 into crude enzyme extracts. The malondialdehyde (MDA) and superoxide anion radical (O2− ) contents in the BDE-47 treated fronds were higher than those in the control fronds, suggesting that L. minor can not effectively relieve reactive oxygen species (ROS). The data above indicates that BDE-47 is toxic to L. minor through acting directly on biomembranes, which induces the production of ROS and thus causes remarkable oxidative damage to cells.
Simultaneous removal of NO and SO2 from flue gas by combined heat and Fe2+ activated aqueous persulfate solutions Chemosphere (IF 4.208) Pub Date : 2017-11-17 Yusuf G. Adewuyi, Nana Y. Sakyi, M.A. Khan
The use of advanced oxidation processes (AOPs) to integrate flue gas treatments for SO2, NOx and Hg0 into a single process unit is rapidly gaining research attention. AOPs are processes that rely on the generation of mainly the hydroxyl radical. This work evaluates the effectiveness of the simultaneous removal of NO and SO2 from flue gas utilizing AOP induced by the combined heat and Fe2+ activation of aqueous persulfate, and elucidates the reaction pathways. The results indicated that both SO2 in the flue gas and Fe2+ in solution improved NO removal, while the SO2 is almost completely removed. Increased temperature led to increase in NO removal in the absence and presence of both Fe2+ and SO2, and in the absence of either SO2 or Fe2+, but the enhanced NO removal due to the presence of SO2 alone dominated at all temperatures. The removal of NO increased from 77.5% at 30 °C to 80.5% and 82.3% at 50 °C and 70 °C in the presence of SO2 alone, and from 35.3% to 62.7% and 81.2%, respectively, in the presence of Fe2+ alone. However, in the presence of both SO2 and Fe2+, NO conversion is 46.2% at 30 °C, increased only slightly to 48.2% at 50 °C; but sharply increased to 78.7% at 70 °C compared to 63.9% for persulfate-only activation. Results suggest NO removal in the presence of SO2 is equally effective by heat-only or heat-Fe2+ activation as the temperature increases. The results should be useful for future developments of advanced oxidation processes for flue gas treatments.
Detoxification and cellular stress responses of unionid mussels Unio tumidus from two cooling ponds to combined nano-ZnO and temperature stress Chemosphere (IF 4.208) Pub Date : 2017-11-17 Halina I. Falfushynska, Lesya L. Gnatyshyna, Anna Ivanina, Inna M. Sokolova, Oksana B. Stoliar
Bivalve mollusks from the cooling reservoirs of fuel power plants (PP) are acclimated to the chronic heating and chemical pollution. We investigated stress responses of the mussels from these ponds to determine their tolerance to novel environmental pollutant, zinc oxide nanoparticles (nZnO). Male Unio tumidus from the reservoirs of Dobrotvir and Burschtyn PPs (DPP and BPP), Ukraine were exposed for 14 days to nZnO (3.1 μM), Zn2+ (3.1 μM) at 18 °C, elevated temperature (T, 25 °C), or nZnO at 25 °C (nZnO + T). Control groups were held at 18 °C. Zn-containing exposures resulted in the elevated concentrations of total and Zn-bound metallothionein (MT and Zn-MT) in the digestive gland, an increase in the levels of non-metalated MT (up to 5 times) and alkali-labile phosphates and lysosomal membrane destabilization in hemocytes. A common signature of nZnO exposures was modulation of the multixenobiotic-resistance protein activity (a decrease in the digestive gland and increase in the gills). The origin of population strongly affected the cellular stress responses of mussels. DPP-mussels showed depletion of caspase-3 in the digestive gland and up-regulation of HSP70, HSP72 and HSP60 levels in the gill during most exposures, whereas in the BPP-mussels caspase-3 was up-regulated and HSPs either downregulated or maintained stable. BPP-mussels were less adapted to heating shown by a glutathione depletion at elevated temperature (25 °C). Comparison with the earlier studies on mussels from pristine habitats show that an integrative ‘eco-exposome’-based approach is useful for the forecast of the biological responses to novel adverse effects on aquatic organisms.
Impact of plant photosystems in the remediation of benzo[a]pyrene and pyrene spiked soils Chemosphere (IF 4.208) Pub Date : 2017-11-17 Anithadevi Kenday Sivaram, Logeshwaran Panneerselvan, Robin Lockington, Ravi Naidu, Mallavarapu Megharaj
The phytoremediation potential of 14 different plant species belonging to C3 and C4 carbon fixation pathway for soils spiked with polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (B[a]P) and pyrene (PYR) was investigated. A glasshouse experiment was conducted to measure the changes in morphological, physiological, and biochemical parameters and the bioaccumulation and biodegradation ability of the plants in soils spiked with 48 and 194 mg kg−1 of B[a]P and PYR, respectively. The per cent removal efficacy of B[a]P and PYR by the tested plant species over a period of 50 days was from 6 to 26% and 14–40% respectively. The maximum removal of both B[a]P and PYR was observed in Sudan grass (C4), vetiver (C4), maize (C4), and sunflower (C3). In terms of accumulation in root and shoot, the concentration of PYR was higher in both C3 and C4 plant species when compared to B[a]P. Overall the results indicated that C4 plants were more efficient than their C3 counterparts in terms of morphological, physiological, biochemical and degradation ability of PAHs.
Measuring and modeling surface sorption dynamics of organophosphate flame retardants on impervious surfaces Chemosphere (IF 4.208) Pub Date : 2017-11-17 Y. Liang, X. Liu, M.R. Allen
Understanding the sorption mechanisms for organophosphate flame retardants (OPFRs) on impervious surfaces is important to improve our knowledge of the fate and transport of OPFRs in indoor environments. The sorption processes of semivolatile organic compounds (SVOCs) on indoor surfaces are heterogeneous (multilayer sorption) or homogeneous (monolayer sorption). In this study, we adopted simplified Langmuir isotherm and Freundlich isotherm in a dynamic sink model to characterize the sorption dynamics of OPFRs on impervious surfaces such as stainless steel and made comparisons between the two models through a series of empty chamber studies. The tests involve two types of stainless steel chambers (53-L small chambers and 44-mL micro chambers) using tris(2-chloroethyl)phosphate (TCEP) and tris(1-chloro-2-propyl)phosphate (TCPP) as target compounds. Our test results show that the dynamic sink model using Freundlich isotherm can better represent the sorption process in the empty small chamber. Micro chamber test results from this study show that the sink model using both simplified Langmuir isotherm and Freundlich isotherm can well fit the measured gas-phase concentrations of OPFRs. We further applied both models and the parameters obtained to predict the gas phase concentrations of OPFRs in a small chamber with an emission source. Comparisons between model predictions and measurements demonstrate the reliability and applicability of the sorption parameters.
Toxic Effects of Different Types of Zinc Oxide Nanoparticles on Algae, Plants, Invertebrates, Vertebrates and Microorganisms Chemosphere (IF 4.208) Pub Date : 2017-11-16 Jing Hou, Yazhou Wu, Xin Li, Benben Wei, Shiguo Li, Xiangke Wang
Concerns about the potential environmental risks of zinc oxide nanoparticles (ZnO NPs) are becoming an important issue because of their rapid growth in different fields. ZnO NPs are inevitably released in the environment during the production, transport, use and disposal process. Therefore, it is necessary to understand their toxicities and mode of actions. This review summarizes the toxic effects of ZnO NPs with different properties and exposed conditions on different species. The mechanisms of ZnO NPs on living organisms could be mainly attributed to one or more of the following aspects: the physical damage of direct contact, the dissolved zinc ions and the ROS-mediated mechanism. This paper systematically reviews the toxic effects of ZnO NPs on organisms and puts forward the existing problems, which are helpful for the safe and efficient use of ZnO NPs, providing the basis for further study of the toxic effects of ZnO NPs and establishing a comprehensive and safe evaluation system.
Tree bark as a bioindicator of the presence of scandium, yttrium and lanthanum in urban environments Chemosphere (IF 4.208) Pub Date : 2017-11-16 V. Minganti, Drava G
Although rare earth elements (REEs) are important in modern industry, few processes use them, so the possibility of these elements being dispersed in the environment is small. For this reason, there are few studies on their presence in urban environments. REEs exhibit similar chemical properties, and Group 3 elements may be used as indicators of the presence of other REEs in the environment. Tree bark is a suitable collector of airborne trace elements and has been successfully used as a bioindicator. In this study, samples of holm oak bark were collected from three sampling sites subjected to different anthropic pressures (one area is far from human influence, while the other two sites are urban areas characterized by different types of human impact). The reference area is significantly different from urban areas where the concentrations measured are up to 5 times higher (Y) than the reference area. The differences between the two urban areas are also significant. The presence of industrial activities causes a 50% higher exposition of the population with respect to an urban area where only residential activities are present. In the case of La, there is no significant difference between the reference and the residential areas, while the industries are responsible for higher La concentrations (0.9 μg g-1vs. 0.4‒0.6 μg g-1). The availability of samples, due to the wide distribution of trees in urban environments, makes possible the production of maps indicating the sources of these elements and highlighting areas which are critical for certain atmospheric pollutants.
Occurrence of benzothiazole, benzotriazole and benzenesulfonamide derivates in outdoor air particulate matter samples and human exposure assessment Chemosphere (IF 4.208) Pub Date : 2017-11-16 Alba Maceira, Rosa Maria Marcé, Francesc Borrull
Benzothiazole (BTHs), benzotriazole (BTRs) and benzenesulfonamide (BSAs) derivates are high production volume chemicals and they are used in several industrial and household applications, therefore it is expected their occurrence in various environments, especially water and air. In this study we developed a method based on gas chromatography-mass spectrometry (GC-MS) combined with pressurised liquid extraction (PLE) to simultaneously determine four BTR, five BTH and six BSA derivates in the particulate matter (PM10) of outdoor air samples collected in quartz fibre filters (QFFs). To the best of our knowledge, this is the first time these compounds have been determined in open ambient environments. Under optimised conditions, method recoveries at the lower and upper concentration levels (0.8 and 4.2 ng m−3) ranged from 70 to 120%, except for 1-H-benzothiazole and 2-chlorobenzothiazole, which were about 50%. The repeatability of the method was usually below 20% (n = 3, %RSD) for both concentration levels. This method enables the contaminants to be detected at pg m−3 concentration levels. Several samples from two different sites influenced by local industries showed that BTRs, followed by BTHs, were the most detected compounds, whereas BSAs were hardly found. The most frequently determined compounds were 1-H-benzothiazole, 2-chlorobenzothiazole, 1-H-benzotriazole, 2-hydroxibenzothiazole, 5,6-dimethyl-1-H-benzotriazole and the isomers 4- and 5-methyl-1-H-benzotriazole. With the concentrations found, the human exposure assessment and health risk characterization via ambient inhalation were also evaluated taking into account different subpopulation groups classified by age for the two sampling points.
Sample handling and data processing for fluorescent excitation-emission matrix (EEM) of dissolved organic matter (DOM) Chemosphere (IF 4.208) Pub Date : 2017-11-16 Minkyu Park, Shane A. Snyder
In environmental engineering and science, fluorescent excitation-emission matrix (EEM) has increasingly been utilized to characterize chromophoric dissolved organic matter (CDOM). This study aims to delineate data processing, including calculation of total fluorescence (TF) which is an emerging water quality parameter often used as a surrogate for trace organic contaminant (TOrC) removal by advanced water treatment processes. In addition, sample handling procedures such as storage, use of preservatives, and oxidant quenching agents were evaluated. In this study, three antimicrobial preservatives were tested: sodium azide, sodium omadine, and thymol. All the tested preservatives altered optical properties of samples, and were therefore not suitable for the preservation of EEM samples. Without preservative, storage of samples at 4 °C maintained TF within 7.5% of its original value for 21 days, while TF of samples stored at the room temperature more drastically changed (up to 15%). The impacts of three oxidant quenching agents including ascorbic acid, sodium bisulfite, and sodium thiosulfate on EEM were also tested. Among the quenching agents, sodium bisulfite was found to be suitable since it little influenced optical properties of samples while the other two were not favorable due to interference. We also scrutinized the use of TF as surrogate to monitor micropollutant rejection by nanofiltration membrane.
Degradation of diethyl phthalate (DEP) by UV/persulfate: An experiment and simulation study of contributions by hydroxyl and sulfate radicals Chemosphere (IF 4.208) Pub Date : 2017-11-16 Ziying Wang, Yisheng Shao, Naiyun Gao, Xian Lu, Na An
Degradation of diethyl phthalate (DEP) by ultraviolet/persulfate (UV/PS) process at different reaction conditions was evaluated. DEP can be degraded effectively via this process. Both tert-butyl (TBA) and methanol (MeOH) inhibited the degradation of DEP with MeOH having a stronger impact than TBA, suggesting sulfate radical ( ) and hydroxyl radical (HO ) both existed in the reaction systems studied. The second-order rate constants of DEP reacting with and HO were calculated to be ( 6.4 ± 0.3 ) × 10 7 M−1s−1 and ( 3.7 ± 0.1 ) × 10 9 M−1s−1, respectively. To further access the potential degradation mechanism in this system, the pseudo-first-order rate constants (ko) and the radical contributions were modeled using a simple steady-state kinetic model involving and HO . Generally, HO had a greater contribution to DEP degradation than . The ko of DEP increased as PS dosages increased when PS dosages were below 1.9 mM. However, it decreased with increasing initial DEP concentrations, which might be due to the radical scavenging effect of DEP. The ko values in acidic conditions were higher than those in alkaline solutions, which was probably caused by the increasing concentration of hydrogen phosphate (with higher scavenging effects than dihydrogen phosphate) from the phosphate buffer as pH values rose. Natural organic matter and bicarbonate dramatically suppressed the degradation of DEP by scavenging and HO . Additionally, the presence of chloride ion (Cl−) promoted the degradation of DEP at low Cl− concentrations (0.25–1 mM). Finally, the proposed degradation pathways were illustrated.
Neurobehavioral assessment of rats exposed to pristine polystyrene nanoplastics upon oral exposure Chemosphere (IF 4.208) Pub Date : 2017-11-16 Mohammad Rafiee, Leila Dargahi, Akbar Eslami, Elmira Beirami, Mahsa Jahangiri-rad, Siamak Sabour, Fatemeh Amereh
The increasing use of plastics has raised concerns about pollution of freshwater by these polymeric materials. Knowledge about their potential effects on environmental and public health is limited. Recent publications have suggested that the degradation of plastics will result in the release of nano-sized plastic particles to the environment. Therefore, it is of utmost importance to gain knowledge about whether and how nanoplastics affect living organisms. The present study aimed to analyse potential neurobehavioral effects of polystyrene nanoparticles (PS-NPs) after long-term exposure on rat. Potential effects of PS-NPs were investigated using four test dosages (1, 3, 6, and 10 mg PS-NPs/kg of body weight/day) administrated orally with adult Wistar male rats for five weeks. Neurobehavioral tests were chosen to assess a variety of behavioral domains. Particle diameters in test suspensions were determined through dynamic light scattering and showed an average hydrodynamic diameter of approximately 38.92 nm. No statistically significant behavioral effects were observed in all tests performed (p > 0.05). In the elevated plus maze, PS-NPs-exposed rats showed greater number of entries into open arms compared to controls. Also, PS-NPs had no significant influence on body weight of animals. Taking into account the subtle and transient nature of neurobehavioral consequences, however, these results underline the possibility of even pristine plastic nanoparticles to induce behavioral alteration in the rest of the food web, including for marine biota and humans. Indeed even though studied neurobehavioral effects in our study was not statistically significant, the observed subtle effects may be clinically considerable.
Electro-oxidation of Ofloxacin antibiotic by dimensionally stable Ti/Ruo2 anode: Evaluation and mechanistic approach Chemosphere (IF 4.208) Pub Date : 2017-11-16 Ravneet Kaur, Jai Prakash Kushwaha, Neetu Singh
Present study investigates the potential of Ti/RuO2 electrode for degradation and mineralization of Ofloxacin (OFLX) antibiotic from synthetic wastewater by electro-oxidation (EO) method, not reported earlier. Effects of various EO parameters such as applied current (I), initial pH, initial OFLX concentration (C0) and supporting electrolyte concentration on %OFLX removal efficiency and %TOC removal efficiency were systematically studied and reported. Decay kinetics of OFLX by varying C0 and applied I were also studied. Additionally, Mineralization current efficiency and specific energy consumption of OFLX mineralization were evaluated. Moreover, mode of oxidation method involved (direct and/or indirect oxidation) was also explored. Major OFLX transformation products during EO were identified using UPLC-Q-TOF-MS, and possible degradation reaction mechanism was proposed. Furthermore, operating cost analysis was performed to check the economic feasibility of the EO process. The optimum pH and current were found to be 6.8 (natural pH of OFLX wastewater) and 1 A, respectively. Mineralization current efficiency decreased from 7.8% to 4.9% with increase in I value from 0.25 to 1 A. ≈80% of OFLX removal in 30 min of electrolysis and 46.3% TOC removal in 240 min of electrolysis at I = 1 A were observed. Pseudo-first-order kinetic model best fitted the experimental data showing R2 value ≈ 0.99 for all the Co and applied I studied.
Nitrogen removal capacity and bacterial community dynamics of a Canon biofilter system at different organic matter concentrations Chemosphere (IF 4.208) Pub Date : 2017-11-15 María J. García-Ruiz, Paula Maza-Márquez, Jesús González-López, Francisco Osorio
Three Canon bench-scale bioreactors with a volume of 2 L operating in parallel were configured as submerged biofilters. In the present study we investigated the effects of a high ammonium concentration (320 mgNH4+· L−1) and different concentrations of organic matter (0, 100 and 400 mgCOD·L−1) on the nitrogen removal capacity and the bacterial community structure. After 60 days, the Canon biofilters operated properly under concentrations of 0 and 100 mgCOD·L−1 of organic matter, with nitrogen removal efficiencies up to 85%. However, a higher concentration of organic matter (400 mgCOD·L−1) produced a partial inhibition of nitrogen removal (68.1% efficiency). The addition of higher concentrations of organic matter a modified the bacterial community structure in the Canon biofilter, increasing the proliferation of heterotrophic bacteria related to the genera of Thauera, Longilinea, Ornatilinea, Thermomarinilinea, unclassified Chlorobiales and Denitratisoma. However, heterotrophic bacteria co-exist with Nitrosomonas and Candidatus Scalindua. Thus, our study confirms the co-existence of different microbial activities (AOB, Anammox and denitrification) and the adaptation of a fixed-biofilm system to different concentrations of organic matter.
Improving Post-Detonation Energetics Residues Estimations for the Life Cycle Environmental Assessment Process for Munitions Chemosphere (IF 4.208) Pub Date : 2017-11-15 Michael Walsh, Brian Gullett, Marianne Walsh, Matthew Bigl, Johanna Aurell
The Life Cycle Environmental Assessment (LCEA) process for military munitions tracks possible environmental impacts incurred during all phases of the life of a munition. The greatest energetics-based emphasis in the current LCEA process is on manufacturing. A review of recent LCEAs indicates that energetics deposition on ranges from detonations and disposal during training is only peripherally examined through assessment of combustion products derived from closed-chamber testing or models. These assessments rarely report any measurable energetic residues. Field-testing of munitions for energetics residues deposition has demonstrated that over 30% of some energetic compounds remain after detonation, which conflicts with the LCEA findings. A study was conducted in the open environment to determine levels of energetics residue deposition and if combustion product results can be correlated with empirical deposition results. Energetics residues deposition, post-detonation combustion products, and fine aerosolized energetics particles following open-air detonation of blocks of Composition C4 (510 g RDX/block) were quantified. The deposited residues amounted to 3.6 mg of energetic per block of C4, or less than 0.001% of the original energetics. Aerial emissions of energetics were about 7% of the amount of deposited energetics. This research indicates that aerial combustion products analysis can provide a valuable supplement to energetics deposition data in the LCEA process but is insufficient alone to account for total residual energetics. This study demonstrates a need for the environmental testing of munitions to quantify energetics residues from live-fire training.
Application of volume-retarded osmosis and low-pressure membrane hybrid process for water reclamation Chemosphere (IF 4.208) Pub Date : 2017-11-15 Sung-Ju Im, Jungwon Choi, Jung-Gil Lee, Sanghyun Jeong, Am Jang
A new concept of volume-retarded osmosis and low-pressure membrane (VRO-LPM) hybrid process was developed and evaluated for the first time in this study. Commercially available forward osmosis (FO) and ultrafiltration (UF) membranes were employed in a VRO-LPM hybrid process to overcome energy limitations of draw solution (DS) regeneration and production of permeate in the FO process. To evaluate its feasibility as a water reclamation process, and to optimize the operational conditions, cross-flow FO and dead-end mode UF processes were individually evaluated. For the FO process, a DS concentration of 0.15 g mL−1 of polysulfonate styrene (PSS) was determined to be optimal, having a high flux with a low reverse salt flux. The UF membrane with a molecular weight cut-off of 1 kDa was chosen for its high PSS rejection in the LPM process. As a single process, UF (LPM) exhibited a higher flux than FO, but this could be controlled by adjusting the effective membrane area of the FO and UF membranes in the VRO-LPM system. The VRO-LPM hybrid process only required a circulation pump for the FO process. This led to a decrease in the specific energy consumption of the VRO-LPM process for potable water production, that was similar to the single FO process. Therefore, the newly developed VRO-LPM hybrid process, with an appropriate DS selection, can be used as an energy efficient water production method, and can outperform conventional water reclamation processes.
Can liming reduce cadmium (Cd) accumulation in rice (Oryza sativa) in slightly acidic soils? A contradictory dynamic equilibrium between Cd uptake capacity of roots and Cd immobilisation in soils Chemosphere (IF 4.208) Pub Date : 2017-11-15 Yongjie Yang, Jiangmin Chen, Qina Huang, Shaoqing Tang, Jianlong Wang, Peisong Hu, Guosheng Shao
Cadmium (Cd) accumulation in rice is strongly controlled by liming, but information on the use of liming to control Cd accumulation in rice grown in slightly acidic soils is inconsistent. Here, pot experiments were carried out to investigate the mechanisms of liming on Cd accumulation in two rice varieties focusing on two aspects: available/exchangeable Cd content in soils that were highly responsive to liming, and Cd uptake and transport capacity in the roots of rice in terms of Cd accumulation-relative gene expression. The results showed that soil availability and exchangeable iron, manganese, zinc and Cd contents decreased with increased liming, and that genes related to Cd uptake (OsNramp5 and OsIRT1) were sharply up-regulated in the roots of the two rice varieties. Thus, iron, manganese, zinc and Cd contents in rice plants increased under low liming applications but decreased in response to high liming applications. However, yield and rice quantities were only slightly affected. These results indicated that Cd accumulation in rice grown in slightly acidic soils presents a contradictory dynamic equilibrium between Cd uptake capacity by roots and soil Cd immobilisation in response to liming. The enhanced Cd uptake capacity under low liming dosages increases risks to human health.
Comparative investigation of X-ray contrast medium degradation by UV/chlorine and UV/H2O2 Chemosphere (IF 4.208) Pub Date : 2017-11-15 Xiujuan Kong, Jin Jiang, Jun Ma, Yi Yang, Suyan Pang
The degradation of iopamidol and diatrizoate sodium (DTZ) by UV/chlorine was carried out according to efficiency, mechanism, and oxidation products, and compared to that by UV/H2O2. The pseudo-first order rate (k′) of iopamidol and DTZ was accelerated by UV/chlorine compared to that by UV and chlorine alone. k′ of iopamidol and DTZ by UV/chlorine increased with increasing chlorine dosage. Both of iopamidol and DTZ could not be effectively removed by UV/H2O2 compared to that by UV/chlorine. Secondary radicals (Cl2<img border="0" alt="radical dot" src="https://cdn.els-cdn.com/sd/entities/rad">− and ClO<img border="0" alt="radical dot" src="https://cdn.els-cdn.com/sd/entities/rad">) rather than primary radicals (HO<img border="0" alt="radical dot" src="https://cdn.els-cdn.com/sd/entities/rad"> and Cl<img border="0" alt="radical dot" src="https://cdn.els-cdn.com/sd/entities/rad">) were demonstrated to be mainly responsible for the enhanced removal of iopamidol and DTZ by UV/chlorine. The oxidation products of iopamidol and DTZ resulting from UV/chlorine and UV/H2O2 process were identified, and differences existed in the two systems. IO3− (the desired sink of I−) was the major inorganic product in the UV/chlorine process whereas I− was the predominant inorganic product in the UV/H2O2 process. The formation of chlorine-containing products during the degradation of iopamidol and DTZ by UV/chlorine was also observed. H-abstraction, additions, de-iodination were shared during the degradation of iopamidol by UV/chlorine and UV/H2O2. Neutral pH condition was preferred for the removal of iopamidol and DTZ by UV/chlorine. UV/chlorine could also be applied in real waters for the removal of iopamidol and DTZ.
Leaching of TCIPP from furniture foam is rapid and substantial Chemosphere (IF 4.208) Pub Date : 2017-11-15 William A. Stubbings, Stuart Harrad
A series of laboratory experiments were conducted, in which waste furniture polyurethane foam samples containing tris (1-chloro-2-propyl) phosphate (TCIPP) were contacted with a range of leaching fluids, formulated to simulate the composition of landfill leachate. Leaching was examined under a number of different scenarios, such as: dissolved humic matter concentration, pH, and temperature, as well as the effect of agitation, and waste:leaching fluid contact duration. In addition to single batch (no replenishment of leaching fluid), serial batch (draining of leachate and replenishment with fresh leaching fluid at various time intervals) experiments were conducted. Leaching of TCIPP from PUF appears to be a first order process. Concentrations of TCIPP in leachate generated by the experiments in this study ranged from 13 mg L−1 to 130 mg L−1. In serial batch leaching experiments, >95% of TCIPP was depleted from PUF after 168 h total contact with leaching fluid. Our experiments indicate leaching is potentially a very significant pathway of TCIPP emissions to the environment.
New particle formation and growth at a suburban site and a background site in Hong Kong Chemosphere (IF 4.208) Pub Date : 2017-11-14 X.P. Lyu, H. Guo, H.R. Cheng, D.W. Wang
Atmospheric nanoparticles have great impacts on human health and global climate change. The number concentrations and size distributions of nanoparticles in the size range of 5.5–350.4 nm were detected at a background site and a suburban site in Hong Kong from summer to winter in 2011 and in autumn of 2013, respectively. Significantly higher particle number concentrations in all modes were observed at the suburban site (p < 0.05) during the sampling periods, possibly due to stronger primary emissions/regional transport and more intensive new particle formation (NPF). Particle number concentrations were much enhanced under northerly winds at both sites, resulting from regional transport of Aitken and accumulation mode particles, enhanced local NPF and occasionally low condensation sink. NPF was mainly limited by the precursors of condensable vapors and oxidative capacity of the atmosphere at the background site and the suburban site, respectively. In most cases, the formation rate of 5.5 nm particles was a function of sulfuric acid vapor to the power of 1.32 ± 0.34 at the background site and 0.81 ± 0.31 at the suburban site, abiding by the cluster activation theory. However, ozonolysis of monoterpenes (particularly α-pinene) might also drive NPF, particularly in the afternoon. These reactions also contributed to the growth of nucleation mode particles, which was largely explained by sulfuric acid vapor (73.6 ± 10% at the background site and 60.4 ± 9.8% at the suburban site). In contrast, the oxidations of isoprene, β-pinene and aromatics (particularly xylenes and trimethylbenzenes) were found to participate in the growth of Aitken mode particles.
Ammonium N influences the uptakes, translocations, subcellular distributions and chemical forms of Cd and Zn to mediate the Cd/Zn interactions in dwarf polish wheat (Triticum polonicum L.) seedlings Chemosphere (IF 4.208) Pub Date : 2017-11-14 Yiran Cheng, Chao Wang, Songyue Chai, Wendi Shuai, Lina Sha, Haiqin Zhang, Houyang Kang, Xing Fan, Jian Zeng, Yonghong Zhou, Yi Wang
Ammonium (NH4+) would influence the uptake and translocation of Cd and Zn to mediate their interactions in wheat. Thus, the effects of NH4+ on Cd and Zn uptake, translocation, subcellular distributions and Cd chemical forms in dwarf polish wheat (DPW, Triticum polonicum L.) under Cd, Zn and Cd + Zn stresses with lack or supply of NH4+ was investigated. The biomasses of root and shoot were reduced by NH4+. NH4+ enhanced Cd and Zn uptakes, but inhibited their translocations. Under lack and supply of NH4+, Zn inhibited Cd uptakes, but promoted Cd translocations. Meanwhile, NH4+ reinforced the inhibition of Cd uptake and the promotion of Cd translocation caused by Zn. Cd inhibited Zn uptake and promoted Zn translocation under lack of NH4+. Meanwhile, Cd slightly reduced the Zn uptake, but did not affect the translocation under supply of NH4+. Therefore, NH4+ alleviated the inhibition of Zn uptake and partly reduced the promotion of Zn translocation stimulated by Cd. NH4+ and Zn changed the subcellular distributions and chemical forms of Cd. NH4+ and Cd also influenced the subcellular distributions of Zn. The changed subcellular distributions and chemical forms were associated with Cd and Zn uptakes and translocations, which physiologically revealed and illustrated NH4+ participates in Cd/Zn interactions.
An in situ study of growth of Lemongrass Cymbopogon flexuosus (Nees ex Steud.) W. Watson on varying concentration of Chromium (Cr+6) on soil and its bioaccumulation: Perspectives on phytoremediation potential and phytostabilisation of chromium toxicity Chemosphere (IF 4.208) Pub Date : 2017-11-14 Deepak Kumar Patra, Chinmay Pradhan, Hemanta Kumar Patra
Chromium (Cr) contamination in soil is a growing concern in sustainable agricultural production and food safety. Remediation of Cr from contaminated soils is a challenging task which may not only help in sustaining agriculture but also in minimizing adverse environmental impacts. Pot culture experiments were performed with the application of varied concentration of Cr+6 to assess the Chromium accumulation potential of Lemongrass and to study the impact of toxic concentration of Cr+6 on morphological, physiological and biochemical parameters of the plant. The results showed an increasing accumulation trend of Chromium with increasing Chromium concentrations in both root and shoot of 60 days old Lemongrass plants, while the protein and chlorophyll contents decreased. Similarly, accumulation of Cr increased the levels of proline and antioxidant enzymes indicating the enhanced damage control activity. The potentiality of the plant with the capacity to accumulate and stabilize Cr compound in Cr contaminated soil by phytoremediation process has been explored in the present investigation.
Analysis of extracellular polymeric substances (EPS) and ciprofloxacin-degrading microbial community in the combined Fe-C micro-electrolysis-UBAF process for the elimination of high-level ciprofloxacin Chemosphere (IF 4.208) Pub Date : 2017-11-14 Longlong Zhang, Qinyan Yue, Kunlun Yang, Pin Zhao, Baoyu Gao
Extracellular polymeric substances (EPS) and ciprofloxacin-degrading microbial community in the combined Fe-C micro-electrolysis and up-flow biological aerated filter (UBAF) process for the treatment of high-level ciprofloxacin (CIP) were analyzed. The research demonstrated a great potential of Fe-C micro-electrolysis-UBAF for the elimination of high-level CIP. Above 90% of CIP removal was achieved through the combined process at 100 mg L−1 of CIP loading. In UBAF, the pollutants were mainly removed at 0–70 cm heights. Three-dimensional fluorescence spectrum (3D-EEM) was used to characterize the chemical structural of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) extracted from biofilm sample in UBAF. The results showed that the protein-like substances in LB-EPS and TB-EPS had no clear change in the study. Nevertheless, an obvious release of polysaccharides in EPSs was observed during long-term exposure to CIP, which was considered as a protective response of microbial to CIP toxic. The high-throughput sequencing results revealed that the biodiversity of bacteria community became increasingly rich with gradual ciprofloxacin biodegradation in UBAF. The ciprofloxacin-degrading microbial community was mainly dominated by Proteobacteria and Bacteroidetes. Microorganisms from genera Dechloromonas, Brevundimonas, Flavobacterium, Sphingopyxis and Bosea might take a major role in ciprofloxacin degradation. This study provides deep theoretical guidance for real CIP wastewater treatment.
Alterations of Mitochondrial Antioxidant Indexes and Apoptosis in Duck Livers Caused by Molybdenum or/and Cadmium Chemosphere (IF 4.208) Pub Date : 2017-11-14 Xueyan Dai, Chenghong Xing, Huabin Cao, Junrong Luo, Tiancheng Wang, Ping Liu, Xiaoquan Guo, Guoliang Hu, Caiying Zhang
AbstractCadmium (Cd) and high Molybdenum (Mo) can lead to adverse reactions on animals, but the co-induced toxicity of Mo and Cd to liver in ducks was not well understood. To investigate the co-induced toxic effects of Mo combined with Cd on mitochondrial oxidative stress and apoptosis in duck livers. 240 healthy 11-day-old ducks were randomly divided into 6 groups (control, LMo group, HMo group, Cd group, LMoCd group and HMoCd group). After being treated for 30, 60, 90 and 120 days, liver mitochondrial antioxidant indexes, ceruloplasmin (CP), metallothionein (MT), Bak-1 and Caspase-3 genes mRNA expression levels, and ultrastructural changes were evaluated. The results showed that total antioxidative capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD) and xanthine oxidase (XOD) activities in experimental groups were decreased, whereas malondialdehyde (MDA) content and nitric oxide synthase (NOS) activity were increased compared with control group, and these changes of co-treated groups were more obvious in the later period of the experiment. The mRNA expression levels of CP, Bak-1 and Caspase-3 were up-regulated in experimental groups compared with control group and showed significant difference between co-treated groups and single treated groups. The mRNA expression level of MT in Cd group was higher than that in co-treated groups. Additionally, ultrastructural changes showed karyopyknosis, mitochondrial swelling, vacuolation and disruption of mitochondrial cristae in co-treated groups. Taken together, it was suggested that dietary Mo and Cd might lead to mitochondrial oxidative stress and apoptosis in duck livers, and it showed a possible synergistic relationship between the two elements.
Saline soil properties, quality and productivity of wheat grown with bagasse ash and thiourea in different climatic zones Chemosphere (IF 4.208) Pub Date : 2017-11-14 Mahmoud F. Seleiman, Ahmed M.S. Kheir
Soil salinity and atmosphere temperature change have negative impacts on crop productivity and its quality and can pose a significant risk to soil properties in semi-arid regions. We conducted two field experiments in North (first zone) and South (second zone) of Egypt to investigate the effects of soil bagasse ash (10 ton ha−1), foliar thiourea (240 g ha−1) and their combination in comparison to the control treatment on saline soil properties and productivity and quality traits of wheat. All studied treatments were received the recommended rate of N, P and K fertilizations. Combination of soil bagasse ash and foliar thiourea application resulted in a significant improvement of most studied soil properties (i.e. EC, compaction, hydraulic conductivity, OM and available P, K, N contents) after harvest in comparison to other treatments in both of zones. Also, it enhanced growth and grain yield of wheat in terms of photosynthesis related attributes and yield components. Moreover, combination of soil bagasse ash and foliar thiourea application resulted in superior grain quality traits in terms of carbohydrate, fibre, protein and ash contents than separated application of soil bagasse ash, foliar thiourea or even control treatment. In conclusion, combination of soil bagasse ash and foliar thiourea application can be used as suitable option to enhance plant nutrition, wheat productivity and improve wheat grain quality and soil traits in saline soil as well as can alleviate heat stress.
Degradation of ciprofloxacin using Fenton's oxidation: Effect of operating parameters, identification of oxidized by-products and toxicity assessment Chemosphere (IF 4.208) Pub Date : 2017-11-13 Anirudh Gupta, Anurag Garg
Ciprofloxacin (CPX), a fluoroquinolone antibiotic, is found in the bulk effluents emerged from pharmaceutical industries. Its presence in the effluent may lead to toxicity to the aquatic life and antimicrobial resistance. Hence, the oxidative degradation of CPX by classical Fenton's process was investigated for the present study. The maximum CPX and total organic carbon (TOC) removal from the synthetic wastewater (initial CPX concentration = 100 mg L−1) were 70% and 55%, respectively, under the best reaction conditions ([H2O2]:[Fe2+] = 10, stoichiometric H2O2 concentration = 14.2 mM and initial wastewater pH = 3.0). Five major degradation products could be identified by high resolution liquid chromatography–mass spectrometry (HR LC-MS) which could have resulted by the occurrence of decarboxylation, defluorination, hydroxylation and cleavage of the piperazine ring. The time based detection of ferrous and ferric ions in aqueous phase confirmed the CPX degradation by hydroxyl radicals. A pathway has been proposed for CPX degradation by Fenton's process based on the kinetic decay and/or evolution profiles of CPX and intermediates as well as the release of inorganic ions into the aqueous solution. It was indicated from the rapid respirometric test that the wastewater toxicity was lowered after Fenton's treatment.
Trace elements in the liver of captive and free-ranging European bison (Bison bonasus L.) Chemosphere (IF 4.208) Pub Date : 2017-11-13 Maciej Durkalec, Agnieszka Nawrocka, Michał Krzysiak, Magdalena Larska, Mirosława Kmiecik, Andrzej Posyniak
European bison is classified as a vulnerable species because of many threats. We analyzed the content of toxic and essential elements (Ag, Al, As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mg, Mn, Na, Ni, Pb, Se, Th, Tl, U, V, and Zn) in the livers of 30 captive and free-ranging European bison from the Bison Breedin Center in Smardzewice and from Białowieża Primeval Forest in Poland. The contents of toxic elements were lower than reported previously in European Bison and were similar to those of wild ungulates from non-polluted areas. Accumulation of Cd and Cr was related to the age of animals. We compared the mineral status between captive and freeranging European bison to verify whether the maintenance type could affect concentrations of trace elements in the liver. The concentration of Mn and Zn differed between captive and free-ranging group. Our results were compared to the reference values of essential elements for cattle. All animals from this study were Se-deficient and more than 80% of them have Cu deficiency. Deficiency of Mn was present in 20% of captive and 37% of free-ranging animals whereas Zn in 37% and 3% respectively. Statistical analysis confirmed that Mn and Zn deficiencies were related o the maintenance of animals (p<0.05). We revealed that mineral deficiencies could be an additional threat to the Polish population of European bison. Thus, the monitoring of essential minerals is necessary and future work is required to optimize the supplementation and foddering for preventing the occurrence of mineral deficiencies.
Characterization and mechanism analysis of lincomycin biodegradation with Clostridium sp. strain LCM-B isolated from lincomycin mycelial residue (LMR) Chemosphere (IF 4.208) Pub Date : 2017-11-13 Mengmeng Wang, Chen Cai, Bo Zhang, Huiling Liu
Lincomycin mycelial residue (LMR) is the restricted resource because it contains residual lincomycin, which is producing potential risks to the environment and human health. In this study, lincomycin-degrading strain LCM-B was isolated and identified as Clostridium sp. in the LMR. Strain LCM-B was able to degrade 62.03% of lincomycin at the initial concentration of 100 mg L−1 after incubation for 10 d, while only 15.61% of lincomycin was removed at the initial concentration of 500 mg L−1. The removal efficiency of lincomycin by strain LCM-B decreased as the initial concentration increased. Gene lnuB (which encodes the nucleotidyl transferase) was detected in the isolated strain, and it was proven to participate in lincomycin biodegradation based on the analysis of degradation products and pathway. The results provide a relatively complete understanding of lincomycin biodegradation mechanism. Strain LCM-B is promising to eliminate lincomycin from the LMR.
In situ fabrication of green reduced graphene-based biocompatible anode for efficient energy recycle Chemosphere (IF 4.208) Pub Date : 2017-11-13 Ying Cheng, Megharaj Mallavarapu, Ravi Naidu, Zuliang Chen
Improving the anode configuration to enhance biocompatibility and accelerate electron shuttling is critical for efficient energy recovery in microbial fuel cells (MFCs). In this paper, green reduced graphene nanocomposite was successfully coated using layer-by-layer assembly technique onto carbon brush anode. The modified anode achieved a 3.2-fold higher power density of 33.7 W m-3 at a current density of 69.4 A m-3 with a 75% shorter start period. As revealed in the characterization, the green synthesized nanocomposite film affords larger surface roughness for microbial colonization. Besides, gold nanoparticles, which anchored on graphene sheets, promise the relatively high electroactive sites and facilitate electron transfer from electricigens to the anode. The reduction-oxidation peaks in cyclic voltammograms indicated the mechanism of surface cytochromes facilitated current generation while the electrochemical impedance spectroscopy confirmed the enhanced electron transfer from surface cytochrome to electrode. The green synthesis process has the potential to generate a high performing anode in further applications of MFCs.
Thyroid disruption and reduced mental development in children from an informal e-waste recycling area: a mediation analysis Chemosphere (IF 4.208) Pub Date : 2017-11-13 Lian Liu, Bo Zhang, Kun Lin, Yuling Zhang, Xijin Xu, Xia Huo
This paper aims to evaluate the effects of thyroid disruption on the mental development of children. A total of 258 three-year-old children in Guiyu (e-waste-exposed group) and Nanao (reference group), China were examined. FT3, FT4, TSH, lead (BPb) and cadmium (BCd) in blood were determined, and cognitive and language scores of children were assessed based on the Bayley Scales of Infant Development III. Stepwise multiple regression was used to estimate the relationship between heavy metals and cognitive and language scores; mediation analysis was performed to determine whether thyroid disruption was mechanistically involved. Medians of BPb and BCd in Guiyu were higher than that of Nanao (11.30±5.38 vs. 5.77±2.51 μg/dL BPb; 1.22±0.55 vs. 0.72±0.37 μg/L BCd, both p<0.001). Means of FT4 and TSH in Guiyu were also higher than those in Nanao (16.65±1.83 vs.16.06±1.66 pmol/L FT4, p=0.007; 2.79±1.30 vs. 2.21±1.43 mIU/L TSH, p=0.001). Guiyu children had lower cognitive scores (100.00±25.00 vs. 120.00±20.00, p<0.001) and lower language scores (99.87±7.52 vs. 111.39±7.02, p<0.001). Mediation analysis showed that Pb negatively correlated with both cognitive and language scores (both p<0.001). However, FT3, FT4 and TSH did not significantly mediate the relationship between Pb and mental development of children (all p>0.05). In contrast, Cd correlated with neither cognitive nor language scores (both p>0.05). Results suggest exposure to heavy metal (Pb) reduces cognitive and language skills, and affects thyroid function, but fail to confirm that thyroid disruption is involved in the neurotoxicity induced by Pb-Cd co-exposure.
Effect of copper on the translocation and transformation of polychlorinated biphenyls in rice Chemosphere (IF 4.208) Pub Date : 2017-11-13 Lili Pan, Jianteng Sun, X. Chris Le, Lizhong Zhu
Contamination of organic pollutants in the environment is usually accompanied by heavy metals. However, a little information on the influences of heavy metals on the uptake, translocation and transformation of organic pollutants in plants is available. In this study, ten-day hydroponic exposure was conducted to explore the influence of copper (Cu) on the bioaccumulation and biotransformation of polychlorinated biphenyls (PCBs) in intact young rice (Oryza sativa L.). Low dose of Cu (≤100 μmol/L) increased the accumulation of CB-61 in rice plants, while excess concentrations of Cu (>100 μmol/L) inhibited uptake and translocation of CB-61. Effect of Cu on the uptake of CB-61 was attributed to the Cu-triggered damage to the roots of rice plants. The presence of a moderate dose of Cu (50 μmol/L) enhanced the formation of hydroxylated polychlorinated biphenyls (OH-PCBs) and methoxylated polychlorinated biphenyls (MeO-PCBs), whereas excess concentrations of Cu (250 μmol/L) inhibited the metabolism of CB-61. The effect of Cu on the interconversion between 4′<img border="0" alt="single bond" src="https://cdn.els-cdn.com/sd/entities/sbnd">OH-CB-61 and 4′-MeO-CB-61 was also concentration dependent: the biotransformation was promoted by a moderate concentration of Cu but inhibited by excess concentrations of Cu. The activities of Cytochrome P450 (CYP450) and S-adenosyl-l-methionine (SAM)-dependent methyltransferase in the roots of rice plants exposed to Cu and CB-61 or its derivatives were consistent with the pattern and trend of the metabolites observed in rice roots. These results could provide valuable insights into the interactions and combined effects of PCBs and heavy metals in plants.
A decision support tool for selecting the optimal sewage sludge treatment Chemosphere (IF 4.208) Pub Date : 2017-11-13 Ville Turunen, Jaana Sorvari, Anna Mikola
Sewage sludge contains significant amounts of resources, such as nutrients and organic matter. At the same time, the organic contaminants (OC) found in sewage sludge are of growing concern. Consequently, in many European countries incineration is currently favored over recycling in agriculture. This study presents a Multi-Attribute Value Theory (MAVT)-based decision support tool (DST) for facilitating sludge treatment decisions. Essential decision criteria were recognized and prioritized, i.e., weighted, by experts from water utilities. Since the fate of organic contaminants was in focus, a simple scoring method was developed to take into account their environmental risks. The final DST assigns each sludge treatment method a preference score expressing its superiority compared to alternative methods.The DST was validated by testing it with data from two Finnish municipal wastewater treatment plants (WWTP). The validation results of the first case study preferred sludge pyrolysis (preference score: 0.629) to other alternatives: composting and incineration (score 0.580, and 0.484 respectively). The preference scores were influenced by WWTP dependent factors, i.e., the operating environment and the weighting of the criteria. A lack of data emerged as the main practical limitation. Therefore, not all of the relevant criteria could be included in the value tree. More data are needed on the effects of treatment methods on the availability of nutrients, the quality of organic matter and sludge-borne OCs. Despite these shortcomings, the DST proved useful and adaptable in decision-making. It can also help achieve a more transparent, understandable and comprehensive decision-making process.
Mesoporous nanoplate multi-directional assembled Bi2WO6 for high efficient photocatalytic oxidation of NO Chemosphere (IF 4.208) Pub Date : 2017-11-11 Jun Wan, Xiao Du, Ruimiao Wang, Enzhou Liu, Jia Jia, Xue Bai, Xiaoyun Hu, Jun Fan
Herein, a mesoporous nanoplate multi-directional assembled Bi2WO6 architecture was successfully prepared and applied for the photocatalytic removal of NOx pollutants at low concentrations under visible light and simulated solar light irradiation. Bi2WO6-180-C synthesized at a hydrothermal temperature of 180 °C with calcination exhibited an excellent conversion efficiency in the photocatalytic oxidation of gaseous NO. The crystallinity, morphology, specific surface area, pore environment, light absorption, and separation of photogenerated electrons and holes were investigated by various techniques; the excellent photocatalytic performance of Bi2WO6-180-C was attributed to its special hierarchical mesoporous structure with an appropriate pore size and interconnected porous network, which imparted good gas permeability and fast mass transfer of reaction intermediates and final products of NO oxidation. Furthermore, hierarchical mesoporous Bi2WO6 showed excellent photocatalytic durability and reusability.
Application of membrane bioreactor for sulfamethazine-contained wastewater treatment Chemosphere (IF 4.208) Pub Date : 2017-11-11 Bing-Jing Shi, Yunkun Wang, Yi-Kun Geng, Ru-Dong Liu, Xin-Rong Pan, Wen-Wei Li, Guo-Ping Sheng
The presence of antibiotics in wastewater has been widely confirmed. Membrane bioreactor (MBR), as an efficient wastewater treatment technology, has attracted increasing interest in its ability to remove antibiotics in recent years. However, its long-term operation stability and the underlying mechanisms for antibiotics removal are still poorly understood. In this study, a hollow fiber MBR was used to treat low concentration sulfamethazine (SMZ) contained wastewater. The long-term effects of various SMZ concentrations on nutrients removal, SMZ degradation, and sludge characteristics were investigated. During the 244 days operation, the overall SMZ removal efficiency could reach 95.4 ± 4.5% under various SMZ concentrations and hydraulic retention times. The reactor exhibited high chemical oxygen demand and NH4+-N removal efficiencies, which reached 93.0% and 96.2%, respectively. A sludge concentration of 4.1 ± 0.3 g/L was maintained in the system without excess sludge discharge. The dosage of SMZ had obvious effect on sludge characteristics. The contents of extracellular polymeric substances (EPS) in MBR decreased after a long-term operation of the reactor under SMZ pressure. The low sludge concentration and the reduced EPS content were also beneficial for mitigating membrane fouling. Thus, this study provides a low-cost, efficient and simple approach to treat SMZ-contained wastewater.
Applicability evaluation of advanced processes for elimination of neurophysiological activity of antidepressant fluoxetine Chemosphere (IF 4.208) Pub Date : 2017-11-11 László Szabó, Viktória Mile, Dóra J. Kiss, Krisztina Kovács, Tamás Földes, Tamás Németh, Tünde Tóth, Renáta Homlok, György T. Balogh, Erzsébet Takács, László Wojnárovits
Presence of the antidepressant fluoxetine in different water bodies has raised significant concerns due to its detrimental effects on non-targeted organisms, especially on fish. When seeking for an appropriate technology able to remove fluoxetine residue from a complex water matrix, special attention needs to be paid to the elimination of the neurophysiological activity that eventually lies behind the noxious effects of the parent compound. Our aim was to probe the applicability of advanced oxidation techniques for this purpose using in situ generated free radical system based on OH-initiated peroxyl radical-mediated processes. By performing product analysis experiments along with quantum chemical calculations, the most probable reaction paths were analyzed including aromatic hydroxylation, defluorination, O-dealkylation and C-dealkylation. The candidates for neurophysiological activity were further investigated by molecular docking. The hydroxylated derivatives are well accommodated in the binding pocket of the corresponding protein, suggesting that these compounds may retain the activity of the parent compound. From a worst-case perspective, we suggest that prolonged treatment needs to be applied to further transform hydroxylated derivatives.
Effective flocculation of Microcystis aeruginosa with simultaneous nutrient precipitation from hydrolyzed human urine Chemosphere (IF 4.208) Pub Date : 2017-11-11 Yan-Shan Wang, Zhong-Hua Tong, Long-Fei Wang, Guo-Ping Sheng, Han-Qing Yu
Mechanical harvest of massive harmful algal blooms is an effective measure for bloom mitigation. Yet subsequent processing of the resulting water from algae water separation after the harvesting becomes a new problem since individual algal cells or small algal aggregates are still present in the water. Here, we proposed a novel approach for effectively flocculating the cyanobacteria Microcystis aeruginosa with a removal efficiency of 97% in 6 h using hydrolyzed urine. Nitrogen and phosphorus were simultaneously reclaimed through struvite formation. The addition of Mg2+ promoted the flocculation efficiency and nutrient removal as well as the yield of struvite. Ca2+ could enhance the flocculation efficiency by forming calcium phosphate. During the flocculation process, no significant damage in algal cells was observed. This study provides a novel and sustainable potential for subsequent processing of the resulting water after algae water separation with simultaneous nutrient precipitation and reducing nutrient loads to wastewater treatment plants.
A novel strategy towards sustainable and stable nitritation-denitritation in an A-B process for mainstream municipal wastewater treatment Chemosphere (IF 4.208) Pub Date : 2017-11-10 Jun Gu, Qin Yang, Yu Liu
The conventional activated sludge process is increasingly receiving concerns for its high energy consumption and excess sludge production. To cope with these issues, an A-B process for nitrogen removal via nitritation-denitritation was proposed in previous study which showed the possibility to achieve energy self-sufficient wastewater reclamation. However, nitritation-denitritation in such a process could not be sustained due to excessive COD capture at A-stage. In this study a novel A-B process configuration in which a portion of influent was directed to B-stage was developed for sustainable and stable nitrogen removal via nitrite shunt with minimal impacts on energy recovery. In this process configuration, the bypass flow was found to significantly shape microbial community structure by enriching ammonia oxidizer and denitrifiers against nitrite oxidizer. As the result, about 78% of total nitrogen was removed via nitritation-denitritation. In addition, the potential energy recovery and sludge reduction were not compromised in the proposed A-B process with the bypass of influent to B-stage. It is expected that this study may offer a feasible engineering solution for concurrently achieving direct energy recovery from wastewater at A-stage, and sustainable nitritation-denitritation for nitrogen removal at B-stage.
Place-based screening of mixtures of dominant emerging contaminants measured in Lake Michigan using zebrafish embryo gene expression assay Chemosphere (IF 4.208) Pub Date : 2017-11-10 Jordan Crago, Rebecca Klaper
Determining impacts of emerging contaminants is difficult due to the different concentrations of mixtures of these chemicals over a landscape. Assessment approaches need to account for absorption, distribution, metabolism and excretion of the chemicals in an organism, and potential crosstalk between molecular pathways. The goal of this study was to assess the utility of employing a modified zebrafish embryo toxicity (ZFET) assay that assesses morphological alterations and measurements of estrogen-associated mRNA transcripts, to exposure of a mixtures of chemicals at concentrations measured in several locations in Lake Michigan. The 5 pharmaceuticals in this study were carbamazepine, diltiazem, fluoxetine, gemfibrozil and metformin. Exposures consisted of 4 concentrations of each individual chemical, mixture concentrations measured at seven locations in Lake Michigan, or 17β-estradiol. The relative expression of Estrogen Receptor-alpha, brain aromatase (CYP19A2), and gonadotropin releasing hormone 3 mRNA were measured at the end the 6-d exposure to determine estrogenicity of the individual chemical or mixture. In this study, there was significant induction of CYP19A2 in individual exposures of diltiazem, fluoxetine, gemfibrozil and metformin at concentrations measured in Lake Michigan. Exposure to 5 of the 7 chemical mixtures altered the expression one of the three biomarkers. Transcripts varied across mixtures, indicating that biological screening of whole water samples for potential estrogenicity may need to include alternative molecular pathways other than just steroid receptor binding. This research demonstrates that pairing chemical measurements with a modified ZFET assay that incorporates molecular biomarkers and morphological endpoints could provide location and mixture specific toxic profiling.
Lanthanum toxicity to five different species of soil invertebrates in relation to availability in soil Chemosphere (IF 4.208) Pub Date : 2017-11-10 Jinxia Li, Rudo A. Verweij, Cornelis A.M. van Gestel
This study determined the toxicity of lanthanum, one of the most commonly used rare earth elements (REEs), to five representative soil invertebrates after 3–4 weeks exposure. Toxicity was related to total, 0.01 M CaCl2-extractable and porewater concentrations in the standard LUFA 2.2 soil, and for earthworms also to body concentrations. La sorption to LUFA 2.2 soil, estimated by relating total soil concentrations to CaCl2-extractable or porewater concentrations seemed to reach saturation at >1000 mg La/kg dry soil. Isopod (Porcellio scaber) growth was the most sensitive endpoint, followed by earthworm (Eisenia andrei), enchytraeid (Enchytraeus crypticus), springtail (Folsomia candida) and oribatid mite (Oppia nitens) reproduction, with EC50s of 312 (95% confidence interval: 5.6–619), 529 (295–762), 1010 ((>377 < 3133), 1220 (1180–1250) and 1500 (1250–1750) mg La/kg dry soil, respectively. EC50s related to CaCl2-extractable concentrations ranged between 1.3 (0.046–2.6) and 15.6 (5.6–25.7) mg La/kg dry soil, while porewater-based EC50s were 3.5 (−) and 10.2 (−) mg/L for the springtails and mites, respectively. La uptake in the earthworms linearly increased with increasing exposure concentration with bioaccumulation factors ranging between 0.04 and 0.53 (average ± SE: 0.24 ± 0.032). EC50 for effects on earthworm reproduction related to internal concentrations was 184 (61–301) mg La/kg dry body weight. A risk assessment based on the available toxicity for soil invertebrates, bacteria and plants resulted in an HC5 of approx. 50 mg La/kg dry soil, suggesting that La may affect soil ecosystems at concentrations slightly above natural background levels (6.6–50 mg La/kg dry soil) in non-polluted soils.
Proteomic profile and toxicity pathway analysis in zebrafish embryos exposed to bisphenol A and di-n-butyl phthalate at environmentally relevant levels Chemosphere (IF 4.208) Pub Date : 2017-11-10 Xing Dong, Xuchun Qiu, Shunlong Meng, Hai Xu, Xiangyang Wu, Ming Yang
Bisphenol A (BPA) and di-n-butyl phthalate (DBP) are well-known endocrine-disrupting chemicals (EDCs) that have human health risks. Chronic exposure to BPA and DBP increases the occurrence of human disease. Despite the potential for exposure in embryonic development, the mechanism of action of BPA and DBP on vertebrate development and disease still remains unclear. In the present study, we identified proteins and protein networks that are perturbed by BPA and DBP during zebrafish (Danio rerio) development. Zebrafish embryos were exposed to environmentally relevant levels of BPA (10 μg/L) and DBP (50 μg/L) for 96 h. By iTRAQ labeling quantitative proteomics, a set of 26 and 41 differentially expressed proteins were identified in BPA- and DBP-treated zebrafish embryos, respectively. Integrated toxicity analysis predicted that these proteins function in common regulatory networks that are significantly associated with developmental and metabolic disorders. Exposure to low concentrations of BPA and DBP has potential health risks in zebrafish embryos. Our results also show that BPA and DBP significantly up-regulate the expression levels of multiple network proteins, providing valuable information about the molecular actions of BPA and DBP on the developmental systems.
The coastal environment affects lead and sodium uptake by the moss Hypnum cupressiforme used as an air pollution biomonitor Chemosphere (IF 4.208) Pub Date : 2017-11-10 Marie Renaudin, Sébastien Leblond, Caroline Meyer, Christophe Rose, Emeline Lequy
Several studies suggest that potential competition exists between marine cations and heavy metals for binding sites on the cell wall of mosses. This competition would impact the heavy metal concentration measured in mosses by biomonitoring programs, which may underestimate air pollution by heavy metals in a coastal environment. In the present study, we aim to identify possible mechanisms affecting lead uptake by mosses in a coastal environment, specifically, the competition between lead (Pb2+) and sodium (Na+) for binding sites in Hypnum cupressiforme (Hc). We also compared the response of continental and coastal Hc populations to Pb2+ exposure by immersing the moss samples in artificial solutions that comprised six experimental treatments and subsequently locating and quantifying Pb2+ and Na+ using the sequential elution technique and X-ray microanalyses with a scanning electron microscope. We demonstrated that high concentrations of Pb2+ prevented Na+ from binding to the cell wall. We also examined the effect of the salt acclimation of Hc on Pb2+ and Na+ accumulation. Coastal Hc populations accumulated more Na and less Pb than continental Hc populations in all treatments. Moreover, our results showed treatment effects on the intra/extracellular distribution of Na+, as well as site. This feedback on the influence of salt stress tolerance on Pb2+ uptake by mosses requires further study and can be investigated for other heavy metals, leading to a better use of mosses as biomonitoring tools.
Prevalence and sources of polychlorinated biphenyls in the atmospheric environment of Lake Victoria, East Africa Chemosphere (IF 4.208) Pub Date : 2017-11-10 Kenneth Arinaitwe, Derek C.G. Muir, Bernard T. Kiremire, Phil Fellin, Henrik Li, Camilla Teixeira, Drake N. Mubiru
The large surface area of Lake Victoria (about 68,800 km2) makes it vulnerable to high atmospheric deposition of chemical pollutants. We present measurements of polychlorinated biphenyls (PCBs) from the lake's atmospheric environment. High volume air (24 h) samples were collected within the northern Lake Victoria watershed in Uganda over two periods; 1999–2004 [at Kakira (KAK) and Entebbe (EBB)] and 2008–2010 (at EBB only). Precipitation samples were also collected monthly during the 2008–2010 period at EBB. Analysis for PCBs was done using GC-μECD in a dual column approach. The ranges of ΣPCB concentrations in the KAK air samples were 154–462 pg m−3 (KAK 1999–2000), 26.7–226 pg m−3 (KAK 2003–2004), 27.0–186 pg m−3 (EBB 2003), 46.8–174 pg m−3 (EBB 2004), 19.2–128 pg m−3 (EBB 2008), 45.8–237 pg m−3 (EBB 2009) and 65.6–244 pg m−3 (EBB 2010). The di-, tri-, tetra- and penta-PCBs were predominant in air sample sets while the tetra- and penta-PCBs were predominant in precipitation samples. The mean flux of ΣPCBs in the precipitation samples was 26.9 ng m−2 (range of 14.8–41.5 and median of 27.5). Concentrations at EBB were lower than those reported elsewhere for urban sites in the East and Central African region. Multivariate analysis and analysis of air mass movements suggested influence of combustion sources on the PCB profiles from the region, especially, from the major East African urbanized regions.
Sorption of albendazole in sediments and soils: Isotherms and kinetics Chemosphere (IF 4.208) Pub Date : 2017-11-09 Dragana Mutavdžić Pavlović, Antonija Glavač, Mihaela Gluhak, Mislav Runje
Albendazole is a broad-spectrum anthelmintic drug effective against gastrointestinal parasites in humans and animals. Despite the fact that it has been detected in environment (water, sediment and soil), there is no information on its fate in the environment. So, in order to understand the sorption process of albendazole in environment, the sorption mechanism and kinetic properties were investigated through sorption equilibrium and sorption rate experiments. For that purpose, batch sorption of albendazole on five sediment samples and five soil samples from Croatia's region with different physico-chemical properties was investigated. Except physico-chemical properties of used environmental solid samples, the effects of various parameters such as contact time, initial concentration, ionic strength and pH on the albendazole sorption were studied. The Kd parameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Langmuir sorption models were applied to describe the equilibrium isotherms. The estimated Kd values varied from 29.438 to 104.43 mLgg−1 at 0.01 M CaCl2 and for natural pH value of albendazole solution (pH 6.6). Experimental data showed that the best agreement was obtained with the linear model (R2 > 0.99), while the rate of albendazole sorption is the best described with the kinetic model of pseudo-second-order. Obtained results point to a medium or even strong sorption of albendazole for soil or sediment particles, which is particularly dependent on the proportion of organic matter, pH, copper and zinc in them.
Photodegradation of novel oral anticoagulants under sunlight irradiation in aqueous matrices Chemosphere (IF 4.208) Pub Date : 2017-11-09 Montaha Yassine, Laura Fuster, Marie-Hélène Dévier, Emmanuel Geneste, Patrick Pardon, Axelle Grélard, Erick Dufourc, Mohamad Al Iskandarani, Selim Aït-Aïssa, Jeanne Garric, Hélène Budzinski, Patrick Mazellier, Aurélien S. Trivella
Kinetics of photodegradation of novel oral anticoagulants dabigatran, rivaroxaban, and apixaban were studied under simulated solar light irradiation in purified, mineral, and river waters. Dabigatran and rivaroxaban underwent direct photolysis with polychromatic quantum yields of 2.2 × 10−4 and 4.4 × 10−2, respectively. The direct photodegradation of apixaban was not observed after 19 h of irradiation. Kinetics of degradation of rivaroxaban was not impacted by the nature of the aqueous matrix while photosensitization from nitrate ions was observed for dabigatran and apixaban dissolved in a mineral water. The photosensitized reactions were limited in the tested river water (Isle River, Périgueux, France) certainly due to the hydroxyl radical scavenging effect of the dissolved organic matter. The study of photoproduct structures allowed to identify two compounds for dabigatran. One of them is the 4-aminobenzamidine while the second one is a cyclization product. In the case of rivaroxaban, as studied by very high field NMR, only one photoproduct was observed i.e. a photoisomer. Finally, seven photoproducts were clearly identified from the degradation of apixaban under simulated solar light.
Ecological risk assessment of microcystin-LR in the upstream section of the Haihe River based on a species sensitivity distribution model Chemosphere (IF 4.208) Pub Date : 2017-11-09 Zhiguang Niu, Lei Du, Jiafu Li, Ying Zhang, Zhiwei Lv
The eutrophication of surface water has been the main problem of water quality management in recent decades, and the ecological risk of microcystin-LR (MC-LR), which is the by-product of eutrophication, has drawn more attention worldwide. The aims of our study were to determine the predicted no effect concentration (PNEC) of MC-LR and to assess the ecological risk of MC-LR in the upstream section of the Haihe River. HC5 (hazardous concentration for 5% of biological species) and PNEC were obtained from a species sensitivity distribution (SSD) model, which was constructed with the acute toxicity data of MC-LR on aquatic organisms. The concentrations of MC-LR in the upstream section of the Haihe River from April to August of 2015 were analysed, and the ecological risk characteristics of MC-LR were evaluated based on the SSD model. The results showed that the HC5 of MC-LR in freshwater was 17.18 μg/L and PNEC was 5.73 μg/L. The concentrations of MC-LR ranged from 0.68 μg/L to 32.21 μg/L and were obviously higher in summer than in spring. The values of the risk quotient (RQ) ranged from 0.12 to 5.62, suggesting that the risk of MC-LR for aquatic organisms in the river was at a medium or high level during the study period. Compared with other waterbodies in the world, the pollution level of MC-LR in the Haihe River was at a moderate level. This research could promote the study of the ecological risk of MC-LR at the ecosystem level.
May humic acids or mineral fertilisation mitigate arsenic mobility and availability to carrot plants (Daucus carota L.) in a volcanic soil polluted by as from irrigation water? Chemosphere (IF 4.208) Pub Date : 2017-11-09 Antonio G. Caporale, Paola Adamo, Shah M.G.G. Azam, Maria A. Rao, Massimo Pigna
Carrot (Daucus carota L.) is a widely consumed root vegetable, whose growth and safety might be threatened by growing-medium arsenic (As) contamination. By this work, we evaluated the effects of humic acids from Leonardite and NPK mineral fertilisation on As mobility and availability to carrot plants grown for 60 days in a volcanic soil irrigated with As-contaminated water – representing the most common scenario occurring in As-affected Italian areas. As expected, the irrigation with As-contaminated water caused a serious toxic effect on plant growth and photosynthetic rate; the highest rate of As also inhibited soil enzymatic activity. In contrast, the organic and mineral fertilisation alleviated, at least partially, the toxicity of As, essentially by stimulating plant growth and promoting nutrient uptake. The mobility of As in the volcanic soil and thus its phytoavailability was differently affected by the organic and mineral fertilisers; the application of humic acids mitigated the availability of the contaminant, likely by its partial immobilisation on humic acid sorption sites – thus raising up the intrinsic anionic sorption capacity of the volcanic soil; the mineral fertilisation enhanced the mobility of As in soil, probably due to competition of P for the anionic sorption sites of the soil variable-charge minerals, very affine to available P. These findings hence suggest that a proper soil management of As-polluted volcanic soils and amendment by stable organic matter might mitigate the environmental risk of these soil, thus minimising the availability of As to biota.
Phosphorus recovery and leaching of trace elements from incinerated sewage sludge ash (ISSA) Chemosphere (IF 4.208) Pub Date : 2017-11-08 Le Fang, Jiang-shan Li, Ming Zhi Guo, C.R. Cheeseman, Daniel C.W. Tsang, Shane Donatello, Chi Sun Poon
Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H2SO4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid.
Multiple bioanalytical method to reveal developmental biological responses in zebrafish embryos exposed to triclocarban Chemosphere (IF 4.208) Pub Date : 2017-11-08 Xing Dong, Hai Xu, Xiangyang Wu, Liuqing Yang
Triclocarban (TCC) is a well-known antibacterial agent that is frequently detected in environmental, wildlife and human samples. The potential toxicological effects and action mechanism of TCC on vertebrate development has remained unclear. In the present study, we analyzed phenotypic alterations, thyroid hormone levels, thyroid hormone responsive genes, and proteomic profiles of zebrafish embryos after exposure to a series of concentrations of TCC from 6 h post-fertilization (hpf) to 120 hpf. The most nonlethal concentration (MNLC), lethal concentration 10% (LC10) and lethal concentration 50% (LC50) of TCC for exposures of 96 h were 133.3 μg/L, 147.5 μg/L and 215.8 μg/L, respectively. Our results showed that exposure to TCC decreased heart rate, delayed yolk absorption and swim bladder development at MNLC and LC10. Exposure to MNLC of TCC inhibited thyroid hormone and altered expression of thyroid hormone responsive genes. Furthermore, exposure to 1/20 MNLC of TCC altered expression of proteins related to binding and metabolism, skeletal muscle development and function, as well as proteins involved in nervous system development and immune response, indicating TCC has potential health risks in wildlife and humans at low concentration level.
Unleaded gasoline as a significant source of Pb emissions in the Subarctic Chemosphere (IF 4.208) Pub Date : 2017-11-08 Vladislav Chrastný, Hana Šillerová, Martina Vítková, Anna Francová, Jan Jehlička, Jana Kocourková, Paul E. Aspholm, Lars O. Nilsson, Tore F. Berglen, Henning K.B. Jensen, Michael Komárek
After the phasing out of leaded gasoline, Pb emissions to the atmosphere dramatically decreased, and other sources became more significant. The contribution of unleaded gasoline has not been sufficiently recognized; therefore, we evaluated the impact of Pb from unleaded gasoline in a relatively pristine area in Subarctic NE Norway. The influence of different endmembers (Ni slag and concentrate from the Nikel smelter in Russia, PM10 filters, and traffic) on the overall Pb emissions was determined using various environmental samples (snow, lichens, and topsoils) and Pb isotope tracing. We found a strong relationship between Pb in snow and the Ni smelter. However, lichen samples and most of the topsoils were contaminated by Pb originating from the current use of unleaded gasoline originating from Russia. Historical leaded and recent unleaded gasoline are fully distinguishable using Pb isotopes, as unleaded gasoline is characterized by a low radiogenic composition (206Pb/207Pb = 1.098 and 208Pb/206Pb = 2.060) and remains an unneglectable source of Pb in the region.
Comparative study of dissolved organic matter generated from activated sludge during exposure to hypochlorite, hydrogen peroxide, acid and alkaline: Implications for on-line chemical cleaning of MBR Chemosphere (IF 4.208) Pub Date : 2017-11-08 Weiwei Cai, Yu Liu
Although on-line chemical cleaning has been extensively employed for maintaining the MBR permeability, little attention has been given to the negative impacts of such prevalent membrane cleaning practice. This study thus comparatively investigated the potential release of dissolved organic matter (DOM) from activated sludge upon the exposure to different kinds of frequently-used cleaning reagents, i.e. NaClO, H2O2, HCl and NaOH. It was found that NaClO at 50 and 80 mg L−1 triggered significant release of DOM, while NaOH strongly promoted soluble nitrogen release. However, the DOM generation induced by H2O2 in the range of 0–80 mg L−1 was nearly negligible. The combined analysis by EEM-PARAFAC and LC-OCD-OND further revealed that NaClO-triggered DOM mainly originated from the breakdown of humic substances and other small humics with molecular weight (MW) less than 500 Da. In contrast, proteins and other biopolymers with higher MW highly contributed to DOM induced by NaOH. Most of DOM detected in this study belonged to low molecular weight (LMW) substances, which were not considered readily biodegradable or physically retainable by microfiltration membrane. It appears from this study that DOM generated from suspended activated sludge during membrane cleaning with different chemicals should be taken into serious consideration when water recycle and reuse are concerned.
Derivation of aquatic predicted no-effect concentration (PNEC) for ibuprofen and sulfamethoxazole based on various toxicity endpoints and the associated risks Chemosphere (IF 4.208) Pub Date : 2017-11-08 Qiusen Huang, Qingwei Bu, Wenjue Zhong, Kaichong Shi, Zhiguo Cao, Gang Yu
For pharmaceuticals, the ecological risk assessment based on traditional endpoints of toxicity could not be properly protective in the long run since the mode of action could vary because they are intended for different therapeutic uses. In this study, the predicted no-effect concentrations (PNECs) of two selected pharmaceuticals, ibuprofen (IBU) and sulfamethoxazole (SMX), were derived based on either traditional endpoints of survival and growth data or some nonlethal endpoints such as reproduction, biochemical and molecular data. The PNECs of IBU based on biochemical-cellular and reproduction data were 0.018 and 0.026 μg L−1 that were significantly lower than those derived from other endpoints, while the lowest PNEC for SMX derived from growth data with the concentration of 0.89 μg L−1. Ecological risk assessment was performed for IBU and SMX to the aquatic environment by applying hazard quotient and probabilistic distribution based quotient (DBQs) methods. The results showed that the probability of DBQs of IBU exceeding 0.1 was 11.2%, while for SMX the probability was 0.9% that could be neglected.
Prevalence and predictors of phthalate exposure in pregnant women in Charleston, SC Chemosphere (IF 4.208) Pub Date : 2017-11-08 Abby G. Wenzel, John W. Brock, Lori Cruze, Roger B. Newman, Elizabeth R. Unal, Bethany J. Wolf, Stephen E. Somerville, John R. Kucklick
Phthalates are plasticizers commonly detected in human urine due to widespread exposure from PVC plastics, food packaging, and personal care products. Several phthalates are known antiandrogenic endocrine disruptors, which raises concern for prenatal exposure during critical windows of fetal development. While phthalate exposure is ubiquitous, certain demographics are subject to greater or lesser exposure. We sampled urine from 378 pregnant women during the second trimester of gestation living in Charleston, SC, and measured eight urinary phthalate metabolites as biomarkers of phthalate exposure: monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), and monomethyl phthalate (MMP). Demographic data was collected from questionnaires administered at the time of specimen collection. All phthalate metabolites were detected in over 93% of urine samples. On average, concentrations were highest for MEP (median = 47.0 ng/mL) and lowest for MMP (median = 1.92 ng/mL). Sociodemographic characteristics associated with elevated phthalate concentrations included being unmarried, less educated, having a low income, high body mass index (BMI), and/or being African American. After racial stratification, age, BMI, education, and income were significantly associated with phthalate concentrations in African American women. Marital status was associated with phthalate concentrations in Caucasian women only, with greater concentrations of MBP, MEHHP, MiBP, and MMP in unmarried versus married women. Results of this cross-sectional study provide evidence for significant racial and demographic variations in phthalate exposure.
Adult exposure to bisphenol A in rare minnow Gobiocypris rarus reduces sperm quality with disruption of testicular aquaporins Chemosphere (IF 4.208) Pub Date : 2017-11-08 Yingying Zhang, Yongjing Guan, Ting Zhang, Cong Yuan, Yan Liu, Zaizhao Wang
Bisphenol A (BPA) is an endocrine disrupter which has adverse effects on male reproduction. Aquaporins (AQPs), well known water-selective channels, play important roles in spermatogenesis and sperm functions. However, whether AQPs participate in the process that BPA induces abnormal sperms has not been investigated to date. In the present study, adult male rare minnows Gobiocypris rarus were exposed to environmentally relevant concentrations BPA (15 and 225 μg/L) for 1, 2 and 3 weeks. Results showed that BPA exposure disrupted sperm motility, increased the percentage of abnormal sperm cells, and decreased sperm tolerance to hypotonic solution and sperm fertilization capacity. Meanwhile, protein levels of AQPs were up-regulated, and their distribution in the testis was abnormal following BPA exposure. The following chromatin immune coprecipitation showed that BPA could regulate aqp3 and 8 expression through the ERE in their 5′-flanking region. The present study demonstrated that BPA could decrease the sperm quality in rare minnow, and AQP3 and 8 might play significant roles in this process.
Effect of pH and added slag on the extractability of Si in two Si-deficient sugarcane soils Chemosphere (IF 4.208) Pub Date : 2017-11-07 Richard J. Haynes, Ya-Feng Zhou
The effects of increasing pH on the adsorption and extractability of Si in two Si-deficient Australian sugarcane soils was investigated and the effects of increasing rates of fertilizer Si (as blast furnace slag) on pH and extractable Si were also examined. Equilibrium studies showed that maximum adsorption of Si by the two soils occurred in the pH range 9–10. When soil pH was increased from 5.0 to 6.5, subsequent adsorption of Si by the two soils, as measured by adsorption isotherms, increased. After incubation with progressive lime additions there was a decline in CaCl2− extractable Si due to its increased adsorption and an increase in acid (H2SO4− and acetic acid)-extractable (mainly adsorbed) Si. The increase in acid extractable Si was greater than the decrease in CaCl2− extractable Si suggesting a supply from an additional source. Alkali (Na2CO3 and Tiron)-extractable Si decreased greatly with increasing pH suggesting dissolution of the amorphous (mainly biogenic) pool of silica was occurring with increasing pH. When increasing rates of slag were incubated with the soils, pH, CaCl2− and acid- extractable Si were all increased because upon dissolution slags release both silicic acid and OH− ions. There was, therefore, a positive relationship between extractable Si and soil pH. However, Na2CO3−and Tiron-extractable Si decreased with increasing slag rates (and increasing soil pH) suggesting dissolution of the biogenic pool of soil Si. It was concluded that future research needs to examine the desorption potential of adsorbed Si and the effects of liming on dissolution of the biogenic pool of soil silica under field conditions.
A conceptual study on the formulation of a permeable reactive pavement with activated carbon additives for controlling the fate of non-point source environmental organic contaminants Chemosphere (IF 4.208) Pub Date : 2017-11-07 Shengyi Huang, Chenju Liang
To take advantage of the road pavement network where non-point source (NPS) pollution such as benzene, toluene, ethyl-benzene, and xylene (BTEX) from vehicle traffic exhaust via wet and dry atmospheric deposition occurs, the asphalt pavement may be used as a media to control the NPS pollution. An experiment to prepare an adsorptive porous reactive pavement (PRP) was initiated to explore the potential to reduce environmental NPS vehicle pollution. The PRP was prepared and studied as follows: various activated carbons (AC) were initially screened to determine if they were suitable as an additive in the porous asphalt mixture; various mixtures of a selected AC were incorporated with the design of porous asphalt concrete (PAC) to produce PRP, and the PRP formulations were tested to ensure that they comply with the required specifications; qualified specimens were subsequently tested to determine their adsorption capacity for BTEX in aqueous solution, as compared to conventional PAC. The PRP08 and PRP16 samples, named for the design formulations of 0.8% and 1.6% of AC (by wt. in the formulation), exhibited low asphalt drain-down and low abrasion loss and also met all regulated specifications. The BTEX adsorption capacity measurements of PRP08 and PRP16 were 33–46%, 36–51%, 20–22%, and 6–8% respectively, higher than those obtained from PACs. Based on the test results, PRPs showed good physical performance and adsorption and may be considered as a potential method for controlling the transport of NPS vehicle pollutants.
A mixture of five endocrine-disrupting chemicals modulates concentrations of bisphenol A and estradiol in mice Chemosphere (IF 4.208) Pub Date : 2017-11-07 Tyler Pollock, Rachel E. Weaver, Ramtin Ghasemi, Denys deCatanzaro
Most people in developed countries are exposed to multiple endocrine-disrupting synthetic chemicals. We previously showed that a single dose of triclosan, tetrabromobisphenol A (TBBPA), butyl paraben, propyl paraben, or di(2-ethylhexyl) phthalate elevated concentrations of bisphenol A (BPA) in mice. Here we investigated whether concurrent exposure to lower doses of these five chemicals could modulate concentrations of bisphenol A (BPA) or the natural estrogen, 17β-estradiol (E2). CF1 mice were injected subcutaneously with 0.1 or 0.5 mg of one chemical, or a 0.5 mg mixture containing 0.1 mg of each of all five chemicals, then given dietary 50 μg kg-1 14C-BPA. The mixture elevated 14C-BPA concentrations in the lungs, muscle, uterus, ovaries, kidney, and blood serum of female mice. When administered alone, triclosan and TBBPA elevated 14C-BPA concentrations in the uterus, ovaries, and blood serum. In another experiment, CF1 mice were injected subcutaneously with the 0.5 mg mixture containing 0.1 mg of all five chemicals, then E2 was measured in urine 2–12 h later. The mixture elevated E2 at 8 h after injection in female mice. No treatments significantly altered concentrations of 14C-BPA or E2 in male mice. These data show that these endocrine-disrupting chemicals interact in vivo, magnifying one another’s effects, consistent with inhibition of enzymes that are critical for estrogen metabolism. These findings highlight the importance of considering exposure to multiple chemicals when assessing health outcomes and determining regulatory exposure limits.
Facing the rain after the phase out: Performance evaluation of alternative fluorinated and non-fluorinated durable water repellents for outdoor fabrics Chemosphere (IF 4.208) Pub Date : 2017-11-07 S. Schellenberger, P. Gillgard, A. Stare, A. Hanning, O. Levenstam, S. Roos, I.T. Cousins
Fluorinated durable water repellent (DWR) agents are used to obtain water and stain repellent textiles. Due to the on-going phase-out of DWRs based on side-chain fluorinated polymers (SFP) with “long” perfluoroalkyl chains, the textile industry lacks suitable alternatives with comparable material characteristics. The constant development and optimization of SFPs for textile applications initiated more than half a century ago has resulted in a robust and very efficient DWR-technology and textiles with exceptional hydro- and oleo-phobic properties. The industry is now in the predicament that the long-chain SFPs with the best technical performance have undesirable toxicological and environmental behaviour. This study provides a comprehensive overview of the technical performance of presently available fluorinated and non-fluorinated DWRs as part of a chemical alternatives assessment (CAA). The results are based on a study with synthetic outdoor fabrics treated with alternative DWRs and tested for repellency using industrial standard and complementary methods. Using this approach, the complex structure-property relationships of DWR-polymers could be explained on a molecular level. Both short-chain SFPs and non-fluorinated DWRs showed excellent water repellency and durability in some cases while short-chain SFPs were the more robust of the alternatives to long-chain SFPs. A strong decline in oil repellency and durability with perfluoroalkyl chain length was shown for SFP DWRs. Non-fluorinated alternatives were unable to repel oil, which might limit their potential for substitution in textile application that require repellency towards non-polar liquids.
Non-methane hydrocarbons in a controlled ecological life support system Chemosphere (IF 4.208) Pub Date : 2017-11-07 Kun Dai, Qingni Yu, Zhou Zhang, Yuan Wang, Xinming Wang
Non-methane hydrocarbons (NMHCs) are vital to people's health and plants' growth, especially inside a controlled ecological life support system (CELSS) built for long-term space explorations. In this study, we measured 54 kinds of NMHCs to study their changing trends in concentration levels during a 4-person-180-day integrated experiment inside a CELSS with four cabins for plants growing and other two cabins for human daily activities and resources management. During the experiment, the total mixing ratio of measured NMHCs was 423 ± 283 ppbv at the first day and it approached 2961 ± 323 ppbv ultimately. Ethane and propane were the most abundant alkanes and their mixing ratios kept growing from 27.5 ± 19.4 and 31.0 ± 33.6 ppbv to 2423 ± 449 ppbv and 290 ± 10 ppbv in the end. For alkenes, ethylene and isoprene presented continuously fluctuating states during the experimental period with average mixing ratios of 30.4 ± 19.3 ppbv, 7.4 ± 5.8 ppbv. For aromatic hydrocarbons, the total mixing ratios of benzene, toluene, ethylbenzene and xylenes declined from 48.0 ± 44 ppbv initially to 3.8 ± 1.1 ppbv ultimately. Biomass burning, sewage treatment, construction materials and plants all contributed to NMHCs inside CELSS. In conclusion, the results demonstrate the changing trends of NMHCs in a long-term closed ecological environment's atmosphere which provides valuable information for both the atmosphere management of CELSS and the exploration of interactions between humans and the total environment.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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