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Assessment of Coriolopsis gallica-treated olive mill wastewater phytotoxicity on tomato plants
2016
Daâssi, Dalel | Sellami, Sahar | Frikha, Fakher | Rodriguez-Couto, Susana | Nasri, Moncef | Mechichi, Tahar
The aim of the present study was to evaluate the phytotoxicity of olive mill wastewater (OMW) after being treated by the white-rot fungus Coriolopsis gallica. For this, the effect of irrigation with treated OMW (TOMW) and untreated OMW (UOMW) on tomato plants (Lycopersicon esculentum) for 3 weeks was studied. The control plants were irrigated with distilled water. Agronomic tests were performed in pot experiments in a greenhouse using the randomized complete block (RCB) experimental design. The relative leaf height (RLH), as a morphological parameter, and the content of total phenols in the roots and total chlorophyll [Cha + Chb] and reducing sugars in the leaves, as physiological parameters, were selected as responses of the experimental design. The results obtained showed that [Cha + Chb] in the leaves of tomato growth under TOMW was enhanced by 36.3 and 19.4 % compared to the plant growth under UOMW and to the controls, respectively. Also, reducing sugar concentrations were closed to those of the control plants, ranging from 0.424 to 0.678 g/L for the different dilutions tested. However, the plants irrigated with UOMW showed lower reducing sugar concentrations ranging from 0.042 to 0.297g/L. The optimum RLH (0.537) was observed in the plants irrigated with TOMW diluted at (1:4), this value being higher than that observed in the controls (0.438). Our study proved that the irrigation with TOMW significantly improved tomato growth and photosynthesis activity over those irrigated with UOMW. Optimization of TOMW as a fertilizer was obtained for a dilution of 1:4. From the obtained results, it can be concluded that OMW treated by C. gallica holds potential to be used as a fertilizer for tomato plants.
Show more [+] Less [-]Exploring the correlations between antibiotics and antibiotic resistance genes in the wastewater treatment plants of hospitals in Xinjiang, China
2016
Li, Chao | Lu, Jianjiang | Liu, Jiang | Zhang, Genlin | Tong, Yanbing | Ma, Na
Various antibiotics have been extensively used to treating infectious diseases in hospitals. In this study, the abundance and diversity of antibiotics and antibiotic resistance genes (ARGs) were observed in the wastewater samples from five hospitals in Xinjiang, China. The total concentrations of tetracyclines, sulphonamides, and quinolones in hospital influents ranged from 363.4 to 753.3 ng/L, 285.5 to 634.9 ng/L, and 1355.8 to 1922.4 ng/L, respectively. However, the removal efficiency of tetracyclines, sulphonamides, and quinolones in wastewater treatment processes ranged from 72.4 to 79.3 %, 36.0 to 52.2 %, and 45.1 to 55.4 %, respectively. The contamination levels of the selected ARGs varied in all wastewater samples. The highest relative concentrations of sul1, sul2, tetQ, and qnrS were significantly higher than those of other ARGs in this study. Significant positive correlations between the relative abundance of partial ARGs and concentrations of certain antibiotics were observed in hospital wastewaters. Results show that integrons played an important role in disseminating and distributing ARGs in microorganism systems. Furthermore, strong correlations were observed between tetQ, sulphonamide resistance genes (except sulA) and intI1. This study aimed to determine the contamination levels of antibiotics and ARGs and analyze the relationships among ARGs, and antibiotics and integron genes in hospital wastewaters.
Show more [+] Less [-]Assessing pollution in a Mediterranean lagoon using acid volatile sulfides and estimations of simultaneously extracted metals
2016
Zaaboub, Noureddine | Helali, Mohamed Amine | Martins, Maria Virgínia Alves | Ennouri, Rym | Béjaoui, Béchir | da Silva, Eduardo Ferreira | El Bour, Monia | Aleya, Lotfi
Bizerte Lagoon is a southern Mediterranean semi-enclosed lagoon with a maximum depth of 12 m. After assessing sediment quality, the authors report on the physicochemical characteristics of the lagoon’s surface sediment using SEM (simultaneously extracted metals) and AVS (acid volatile sulfides) as proxies. Biogeochemical tools are used to investigate the environmental disturbance at the water–sediment interface by means of SEM and AVS to seek conclusions concerning the study area’s pollution status. Results confirm accumulation of trace elements in sediment. The use of the SEM-AVS model with organic matter in sediment (ƒOC) confirms possible bioavailability of accumulated trace elements, especially Zn, in the southern part of the lagoon, with organic matter playing an important role in SEM excess correction to affirm a nontoxic total metal sediment state. Individual trace element toxicity is dependent on the bioavailable fraction of SEMMₑₜₐₗ on sediment, as is the influence of lagoon inflow from southern water sources on element bioavailability. Appropriate management strategies are highly recommended to mitigate any potential harmful effects on health from this heavy-metal-based pollution.
Show more [+] Less [-]Metallothionein modulation in relation to cadmium bioaccumulation and age-dependent sensitivity of Chironomus riparius larvae
2016
Toušová, Zuzana | Kuta, Jan | Hynek, David | Adam, Vojtěch | Kizek, René | Bláha, Luděk | Hilscherová, Klára
The goal of this study was to contribute to understanding of the mechanisms behind sensitivity differences between early and late instar larvae of Chironomus riparius and to address the influence of the differences in standard testing approaches on the toxicity evaluation. A 10-day contact sediment toxicity test was carried out to assess sensitivity to cadmium exposure in relation to different age and laboratory culture line origin of test organisms. Chironomid larvae of early (OECD 218 method) and late instar (US-EPA600/R-99/064 method) differed substantially in sensitivity of traditional endpoints (OECD: LOEC 50 and 10 μg Cd/g dry weight (dw); US-EPA: LOEC > 1000 and 100 μg Cd/g dw for survival and growth, respectively). Bioaccumulated cadmium and metallothioneins (MTs) concentrations were analyzed to investigate the role of MTs in reduced sensitivity to cadmium in late instar larvae. Metallothioneins were induced after treatment to greater Cd concentrations, but their levels in relation to cadmium body burdens did not fully explain low sensitivity of late instars to cadmium, which indicates some other effective way of detoxification in late instars. This study brings new information related to the role of MTs in age-dependent toxicant sensitivity and discusses the implications of divergence in data generated by chironomid sediment toxicity tests by standardized methods using different instars.
Show more [+] Less [-]Autoclave treatment of pig manure does not reduce the risk of transmission and transfer of tetracycline resistance genes in soil: successive determinations with soil column experiments
2016
Kang, Yijun | Gu, Xian | Hao, Yangyang | Hu, Jian
The increasing use of antibiotics, especially tetracycline, in livestock feed adversely affects animal health and ecological integrity. Therefore, approaches to decrease this risk are urgently needed. High temperatures facilitate antibiotic degradation; whether this reduces transmission risk and transfer of tetracycline-resistant bacteria (TRBs) and tetracycline resistance genes (TRGs) in soil remains unknown. Successive experiments with soil columns evaluated the effects of autoclaving pig manure (APM) on soil TRB populations and TRGs over time at different soil depths. The data showed sharp increases in TRB populations and TRGs in each subsoil layer of PM (non-APM) and APM treatments within 30 days, indicating that TRBs and TRGs transferred rapidly. The level of TRBs in the upper soil layers was approximately 15-fold higher than in subsoils. TRBs were not dependent on PM and APM levels, especially in the late phase. Nevertheless, higher levels of APM led to rapid expansion of TRBs as compared to PM. Moreover, temporal changes in TRB frequencies in total culturable bacteria (TCBs) were similar to TRBs, indicating that the impact of PM or APM on TRBs was more obvious than for TCBs. TRBs were hypothesized to depend on the numbers of TRGs and indigenous recipient bacteria. In the plough layer, five TRGs (tetB, tetG, tetM, tetW, and tetB/P) existed in each treatment within 150 days. Selective pressure of TC may not be a necessary condition for the transfer and persistence of TRGs in soil. High temperatures might reduce TRBs in PM, which had minimal impact on the transmission and transfer of TRGs in soil. Identifying alternatives to decrease TRG transmission remains a major challenge.
Show more [+] Less [-]Enhanced removal performance by the core-shell zeolites/MgFe-layered double hydroxides (LDHs) for municipal wastewater treatment
2016
Guo, Lu | Zhang, Xiangling | Chen, Qiaozhen | Ruan, Congying | Leng, Yujie
The application of powdered layer double hydroxides (LDHs) in constructed rapid infiltration system (CRIS) appears to be an appreciable problem still unsolved due to the small particle size and the low density. Therefore, the core-shell zeolites/MgFe-LDHs composites were prepared via using co-precipitation method in present study. To investigate the practical applicability, a detailed organics, ammonia, and total phosphorus removal study were carried out in columns to treat the municipal wastewater. The scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) results confirmed the successful synthesis of core-shell zeolites/MgFe-LDHs through coating on the surface of zeolites. Accordingly, the zeolites/MgFe-LDHs largely reduced the COD by 81.14 %, NH₄⁺-N by 81.50 %, and TP by 83.29 %. Phosphate adsorption study revealed that the equilibrium adsorption data were better fitted by Langmuir isothermal model, with the maximum adsorption capacity of 79.3651 mg/kg for zeolites/MgFe-LDHs and 38.4615 mg/kg for the natural zeolites. In addition, economic analysis indicated that the reagent cost of synthesis of zeolites/MgFe-LDHs was economical. Herein, the zeolites/MgFe-LDHs solved the natural zeolites problem for poor P removal and the application of powdered LDHs in the solid/liquid separation process, suggesting that it was applicable as potential substrates for the removal of organics, ammonia, and total phosphorus in CRIS.
Show more [+] Less [-]Adaptability comparison of E. fetida in vermicomposting against sludge from livestock wastewater treatment plant based on their several growth stages
2016
Hao, Xiaoxia | Hu, Hongwen | Li, Xuewei | Jiang, Dongmei | Zhu, Li | Bai, Lin
Vermicomposting is a low-cost, eco-efficient process to deal with organic wastes. Mixtures of swine manure (SM), cow dung (CD), and animal wastewater treatment plant sludge (S) were applied as feeds, and Eisenia fetida was employed in this study to investigate the vermicomposting efficiency based on their several growth stages. The hatching test resulted in a 100 % hatching rate in S₆₀SM₄₀ (60 % S + 40 % SM) mixture, while 4.40 hatchlings per cocoon were observed. The growth of infancy performed best in 0–20 % CD mixtures (0.05 ± 0.002 g), followed by in SM + CD (0.04 ± 0.003 g). The highest growth rate of young and adult E. fetida was noticed in CD + S mixtures (11.14 ± 0.01 and 6.00 ± 0.02 mg/d/worm, respectively), while the higher cocoon production of adults was noticed in S + SM mixtures especially in S₄₀SM₆₀ (537 ± 5 worms). Moreover, the conversion of solids; the modified pH value; the reduction in total organic carbon (TOC); total Kjeldahl nitrogen (TKN), NH₄-N, NO₃-N, and C:N ratio; and the rich in total available phosphorus (TAP) and total potassium (TK) content by young and adult E. fetida were related to the growth of worms. Such work would benefit understanding and to increase the efficiency of vermicompost processing of different wastes.
Show more [+] Less [-]Analyses of combined effects of cytostatic drugs on micronucleus formation in the Tradescantia
2016
Mišík, Miroslav | Filipič, Metka | Nersesyan, Armen | Mišíková, Katarína | Knasmueller, Siegfried | Kundi, M. (Michael)
Recent experiments showed that 5-fluorouracil (5FU), cisplatin (CDDP), etoposide (ET), and imatinib mesylate (IM), which are currently among the most widely used anticancer drugs, cause damage of the genetic material in higher plants. The aim of the present study was to determine whether mixtures of these drugs cause synergistic or antagonistic effects which may have an impact on their environmental safety. Therefore, the effects of binary mixtures of these anticancer drugs on the induction of micronuclei (MN) which reflect structural and numerical chromosomal aberrations were assessed in Tradescantia tetrads. Synergistic/antagonistic effects were determined by comparison with single exposures that would be equally effective in a reference model of independent action. This comparison was performed at two distinct effect sizes. We found clear evidence for synergisms in combination experiments with IM and antagonism in a high-dose experiment with ET and 5FU. Our findings indicate that IM increases the genotoxic effects of other anticancer drugs. The maximal effects which we found were in the range between 19 and 38 % in the excess of effect sizes predicted under independent action. These effects may have an impact on the overall genotoxic activities of untreated hospital waste waters but not on the environment in general as the predicted environmental concentrations of the studied drugs are several orders of magnitude lower as the levels which are required to cause induction of MN in higher plants.
Show more [+] Less [-]Quantifying statistical relationships between commonly used in vitro models for estimating lead bioaccessibility
2016
Yan, Kaihong | Dong, Zhaomin | Liu, Yanju | Naidu, R.
Bioaccessibility to assess potential risks resulting from exposure to Pb-contaminated soils is commonly estimated using various in vitro methods. However, existing in vitro methods yield different results depending on the composition of the extractant as well as the contaminated soils. For this reason, the relationships between the five commonly used in vitro methods, the Relative Bioavailability Leaching Procedure (RBALP), the unified BioAccessibility Research Group Europe (BARGE) method (UBM), the Solubility Bioaccessibility Research Consortium assay (SBRC), a Physiologically Based Extraction Test (PBET), and the in vitro Digestion Model (RIVM) were quantified statistically using 10 soils from long-term Pb-contaminated mining and smelter sites located in Western Australia and South Australia. For all 10 soils, the measured Pb bioaccessibility regarding all in vitro methods varied from 1.9 to 106 % for gastric phase, which is higher than that for intestinal phase: 0.2 ∼ 78.6 %. The variations in Pb bioaccessibility depend on the in vitro models being used, suggesting that the method chosen for bioaccessibility assessment must be validated against in vivo studies prior to use for predicting risk. Regression studies between RBALP and SRBC, RBALP and RIVM (0.06) (0.06 g of soil in each tube, S:L ratios for gastric phase and intestinal phase are 1:375 and 1:958, respectively) showed that Pb bioaccessibility based on the three methods were comparable. Meanwhile, the slopes between RBALP and UBM, RBALP and RIVM (0.6) (0.6 g soil in each tube, S:L ratios for gastric phase and intestinal phase are 1:37.5 and 1:96, respectively) were 1.21 and 1.02, respectively. The findings presented in this study could help standardize in vitro bioaccessibility measurements and provide a scientific basis for further relating Pb bioavailability and soil properties.
Show more [+] Less [-]Crocin protects human embryonic kidney cells (HEK293) from α- and β-Zearalenol-induced ER stress and apoptosis
2016
Ben Salem, Intidhar | Boussabbeh, Manel | Prola, Alexandre | Guilbert, Arnaud | Bacha, Hassen | Lemaire, Christophe | Abid-Essefi, Salwa
α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL) are the major metabolites of Zearalenone (ZEN) and are known to induce many toxic effects. In the present study, we investigated the involvement of endoplasmic reticulum (ER) stress in α- and β-ZOL-mediated toxicity in human kidney cells (HEK293) and evaluated the effect of a common dietary compound Crocin (CRO), from saffron. We show that α- and β-ZOL treatment induces ER stress as evidenced by the upregulation of the 78 kDa glucose-regulated protein (GRP78) and the Growth arrest and DNA damage-inducible protein (GADD34). Activation of the ER stress response is associated with activation of the mitochondrial pathway of apoptosis. This apoptotic process is characterized by an increase in ROS generation and lipid peroxidation, a loss of mitochondrial transmembrane potential (ΔΨm) and activation of caspases. We also demonstrate that the antioxidant properties of CRO help to prevent ER stress and reduce α- and β-ZOL-induced apoptosis in HEK293 cells. Our results suggest that saffron consumption might be helpful to prevent α- and β-ZOL-induced ER stress and toxicity.
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