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Результаты 1391-1400 из 1,535
Combined biodegradation and ozonation for removal of tannins and dyes for the reduction of pollution loads
2012
Kanagaraj, James | Mandal, A. B. (Asit Baran)
PURPOSE: Tannins and dyes pose major threat to the environment by generating huge pollution problem. Biodegradation of wattle extract, chrome tannin and dye compounds using suitable fungal culture namely Aspergillus niger, Penicillium sp. were carried out. In addition to these, ozone treatment was carried out to get higher degradation rate. RESULTS: The results were monitored by carrying out chemical oxygen demand (COD), total organic carbon (TOC), and UV–Vis analysis. The results showed that wattle extract (vegetable tannin) gave better biodegradation rate than dye and chromium compounds. Biodegradation plus ozone showed degradation rates of 92–95%, 94–95%, and 85–87% for the wattle extract, dyes, chromium compounds, respectively. UV–Vis showed that there were no peaks observed for biodegraded samples indicating better degradation rates as compared to the control samples. FT-IR spectra analysis suggested that the formation of flavanoid derivatives, chromic oxide and NH2 compounds during degradation of wattle extract, chromium and dye compounds, respectively, at the peaks of 1,601–1,629 cm−1, 1,647 cm−1, and 1,610–1,680 cm−1. CONCLUSION: The present investigation shows that combination of biodegradation with ozone is the effective method for the removal of dyes and tannins. The biodegradation of the said compounds in combination with ozonation showed better rate of degradation than by chemical methods. The combination of biodegradation with ozone helps to reduce pollution problems in terms of COD, TOC, total dissolved solids and total suspended solids.
Показать больше [+] Меньше [-]Investment threshold and management reflection for industrial system cleaning: a case for China
2012
Fang, Yiping
INTRODUCTION: The recognition that industrial activity plays an essential role in a sustainable society is now widespread. To understand the causal relationship between industrial pollution abatement expenditure and industrial system cleaning level in China is of considerable importance, especially under extremely rapid industrial growth and serious pressure of industrial pollutants abatement context. STUDY METHODS: We use composite index assessment method and regression analysis in this paper. We establish the mathematical model between composite industrial cleaner index and investment intensity for industrial pollutants abatement, and analyze the effects of industrial pollutants treatment and discharge indicators on composite industrial cleaner index in China. RESULTS AND DISCUSSION: Results show that: (1) There is significant nonlinear relationship between composite industrial cleaner index and investment intensity for industrial pollutants abatement. (2) From single indicator perspective, the effect of investment intensity on pollutants treatment indicators is positively, on the contrary, the effect of investment intensity on pollutants discharge indicators is negatively; (3) From decomposition cleaner index perspective, the effect of pollutants discharge level (process control) is higher than pollutants treatment capacity (end-of-pipe) on composite industrial cleaner index; (4) There is threshold between investment intensity and composite cleaner industrial index, it is a crucial reference scale for industrial environmental management in selected period.
Показать больше [+] Меньше [-]Cation and anion leaching and growth of Acacia saligna in bauxite residue sand amended with residue mud, poultry manure and phosphogypsum
2012
Jones, B. E. H. | Haynes, R. J. | Phillips, I. R.
PURPOSE: To examine (1) the effect of organic (poultry manure) and inorganic (residue mud and phosphogypsum) amendments on nutrient leaching losses from residue sand and (2) whether amendments improve the growth of plants in residue sand. METHODS: Leaching columns were established using residue sand. The phosphogypsum-treated surface layer (0–15 cm) was amended with poultry manure and/or bauxite residue mud and the subsurface layer (15–45 cm) was either left untreated or amended with phosphogypsum. RESULTS: Much of the Na+, K+, Cl− and SO 4 2− was lost during the first four leachings. Additions of phosphogypsum to both surface and subsurface layers resulted in partial neutralization of soluble alkalinity. Mean pH of leachates ranged from 8.0 to 8.4, the major cation leached was Na+ and the major balancing anion was SO 4 2− . Where gypsum was not applied to the subsurface, mean pH of leachates was 10.0–10.9, the main cation leached was still Na+ and the main balancing anions were a combination of SO 4 2− and HCO 3 − /CO 3 2− . At the end of the experiment, concentrations of exchangeable Na+ in the subsurface layers were similar regardless of whether gypsum had been applied to that layer or not. Yields of Acacia saligna were promoted by additions of poultry manure to the surface layer but unaffected by gypsum incorporation into the subsurface layer. CONCLUSIONS: Lack of reaction of phosphogypsum with the subsurface layer is unlikely to be a major factor limiting revegetation of residue sand since in the absence of phosphogypsum the excess Na+ leaches with the residual alkalinity (HCO 3 − /CO 3 2− ) rather than SO 4 2− .
Показать больше [+] Меньше [-]Use of inorganic and organic wastes for in situ immobilisation of Pb and Zn in a contaminated alkaline soil
2012
Zhou, Y-F. | Haynes, R. J. | Naidu, R.
PURPOSE: This study aims to examine whether addition of immobilising agents to a sandy, alkaline (pH = 8.1) soil, which had been contaminated with Pb and Zn by airborne particles from a Pb/Zn smelter, would substantially reduce metal bioavailability. METHODS: The effectiveness of five waste materials (blast furnace (BF) slag, alum water treatment (WT) sludge, red mud, sugar mill mud and green waste compost) as metal immobilising agents was evaluated by incubating them with a contaminated soil for a period of 12 months at rates of 5% and 10% (w/w), after which, Rhodes grass was grown in the soils in a greenhouse study. RESULTS: Additions of WT sludge, BF slag and red mud reduced CaCl2, CH3COOH, HCl and EDTA-extractable Zn but compost and mill mud had no appreciable immobilising effects. Additions of all amendments reduced levels of CaCl2, CH3COOH and HCl-extractable Pb although concentrations of EDTA-extractable Pb remained unchanged. A sequential extraction procedure showed that additions of mill mud and compost increased the percentage of total Pb and Zn present in the oxidisable fraction whilst additions of the other materials increased the percentage present in the residual fraction. Rhodes grass yields were promoted greatly by additions of red mud, compost and particularly mill mud, and yields were negatively correlated with tissue Pb concentrations and extractable Pb. CONCLUSIONS: Red mud was the most effective material for lowering extractable Pb and Zn levels simultaneously while mill mud and compost were notably effective for Pb. A field evaluation in the study area is justified.
Показать больше [+] Меньше [-]Alpha radiation exposure decreases apoptotic cells in zebrafish embryos subsequently exposed to the chemical stressor, Cd
2012
Yu, K. N. | Tung, M. M. T. | Choi, V. W. Y. | Cheng, S. H.
The aim of this study was to demonstrate that zebrafish embryos subjected to a priming exposure provided by one environmental stressor (low-dose alpha particles) can induce an adaptive response against a subsequent challenging exposure provided by another environmental stressor (heavy metal Cd). The effect thus identified would be an antagonistic multiple stressor effect. The effects of alpha particle radiation and/or Cd on whole embryos were studied through quantification of apoptotic signals at 24 h post-fertilization (hpf). Embryos were stained with the vital dye acridine orange, followed by counting the stained cells. For each set of experiments, 30 dechorionated embryos were divided into three groups, each having ten embryos. The three groups of embryos were referred to as (A) the control group, which received no more further treatments after dechorionation, (B) Cd-treated group, which did not receive any priming exposure and would receive a challenging exposure at 10 hpf and (C) (alpha + Cd)-treated group, which would receive both priming and challenging exposures. We defined the normalized net number of apoptotic signals in the (alpha + Cd)-treated group as N C * = [(apoptotic signals for (alpha + Cd)-treated group − average apoptotic signals for the corresponding control group)/average apoptotic signals for the corresponding control group] and that in the Cd-treated group as N B* = [(apoptotic signals for Cd-treated group − average apoptotic signals for the corresponding control group)/ average apoptotic signals for the corresponding control group]. By using the non-parametric Mann–Whitney U statistic, we were able to show that N C * was significantly smaller than N B *(p = 0.006). These demonstrated an antagonistic multiple stressor effect between ionizing radiation and Cd through the induction of an adaptive response by the ionizing radiation against subsequent exposures to Cd.
Показать больше [+] Меньше [-]Fifteen years of monitoring of POPs in the breast milk, Czech Republic, 1994–2009: trends and factors
2012
Mikeš, Ondřej | Čupr, Pavel | Kohút, Lukáš | Krsková, Andrea | Černá, Milena
BACKGROUND, AIM AND SCOPE: The breast milk has been recommended to carry out as a monitoring tool for effectiveness evaluation of the Stockholm Convention on Persistent Organic Pollutants (POPs). Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloro-ethane (DDT) and its metabolites (DDX), hexachlorbenzene (HCB) and isomers of hexachlocyklohexane (HCHs) have been monitored in the breast milk of nursing mothers in the Czech Republic since 1994 as a part of The Environmental Health Monitoring System. Knowledge about long-term POPs distribution and accumulation in the human body is crucial to understanding uptake, degradation and subsequent effects as well as to conduct risk assessments. The main aim of this study is to evaluate 15-years long-term trends of selected POPs in human milk in the Czech Republic and to elucidate the questionnaire information about the age, parity and social habits, to the final concentrations. This effectiveness evaluation of POPs restriction is quite precisely after 15-years monitoring campaigns. MATERIALS, METHODS AND RESULTS: The human milk samples (4,753 samples) were analysed for a number of chlorinated organic chemicals including PCBs and selected chlorinated pesticides (OCPs, HCB, HCHs, DDX). The relative change of concentration per year for all chemicals was analysed. The remaining percentages of POPs in breast milk in comparison to 1994 are also expressed. Czech population half-lives of POPs in breast milk, derived from either linear or exponential models were computed. CONCLUSIONS AND PERSPECTIVES: The long-term data indicates a continuation of a decreasing trend of POPs concentrations on breast milk. Our study did not confirm lactation and parity as an important outflux resulting in the decrease in concentrations in mothers, which is in the antagonism with most of the studies. The higher BMI was associated with higher amounts of HCB and lower amounts of higher chlorinated PCBs. The results confirm the effectiveness of restrictions of POPs usage in the Czech Republic. This ongoing long-term study is very useful tool for parametric effectiveness evaluation of Stockholm Convention.
Показать больше [+] Меньше [-]Evaluation of olive oil mill wastewater toxicity on spinach
2012
Asfi, Maria | Ouzounidou, Georgia | Moustakas, Michael
BACKGROUND, AIM, AND SCOPE: Olive oil mill wastewater (OMW), a by-product of the olive oil extraction process, is annually produced in huge amounts in olive-growing areas and represents a significant environmental problem in Mediterranean areas. We studied the impact of OMW dilutions (1:20 and 1:10) on spinach plants in order to evaluate OMW dilutions as a low-cost alternative method for the disposal of this waste. MATERIALS AND METHODS: The effects of OMW dilutions were evaluated on seed germination, shoot and root elongation, biomass production, nutrient uptake and translocation, ascorbic acid content, polyphenols, photosynthetic pigments, and photosynthetic performance of spinach. RESULTS: Plant biomass was more affected than plant height and total chlorophyll; carotenoid and ascorbic acid content progressively decreased with decreasing OMW dilution. Exposure to both OMW dilutions resulted in overaccumulation of total polyphenols, which were negatively correlated to plant biomass and nutrients. Nutrient (Fe, Ca, and Mg) content was insufficient leading to reduced growth. Water use efficiency decreased mainly due to decreased CO2 assimilation rate rather than to a decline of transpiration rate. Disturbances in photosystem II (PSII) photochemical efficiency could be better envisaged by the ratio between variable fluorescence and initial fluorescence (Fv/Fo), which showed much greater amplitude than the maximal photochemical efficiency of PSII photochemistry (Fv/Fm). CONCLUSIONS: From the data obtained, it is suggested that 1:20 OMW dilutions are still phytotoxic and that higher OMW dilutions should be used in order to use this waste for the irrigation of spinach plants.
Показать больше [+] Меньше [-]Exposure to heavy metals in blood and risk perception of the population living in the vicinity of municipal waste incinerators in Korea
2012
Lee, Chung Soo | Lim, Young Wook | Kim, Ho Hyun | Yang, Ji Yeon | Shin, Dong-Chun
BACKGROUND, AIM, AND SCOPE: The purpose of this study was to monitor and present the heavy metal concentrations in the blood of residents of areas near municipal waste incinerators (MWIs), who are more prone to environmental pollution. We also sought to compare and analyze the residents’ perception of environmental pollution as one of the factors affecting heavy metal concentrations in the blood using a survey about the perceived damage caused by the facilities. Since heavy metal levels in the blood can be affected not only by local environmental pollution but also by personal and occupational factors, heavy metal levels in the blood need to be verified and consistently monitored. METHODS: Residents who live within 300 m of MWIs in Seoul are acknowledged to be under indirect influence according to the Waste Disposal Act. A survey was given to 841 residents living within 300 m of a MWI from 2006 to 2009. The concentrations of heavy metals (lead, cadmium, and mercury) in the blood were measured in the 841 surveyed residents and in 105 residents in reference areas. Additionally, the perception of the damage caused by municipal waste incinerators was investigated using scores from 1 to 5 on a Likert scale. RESULTS: The measurements of the heavy metal concentrations in the blood showed that the mean concentrations of lead, cadmium, and mercury were 43.1, 1.7, and 1.3 ug/L, respectively. The blood levels of lead and cadmium were slightly higher in the group of the subjects who had resided the longest near the municipal waste incinerators. When compared with the domestic investigation by the Ministry of Environment, the concentrations of lead and cadmium were a little higher, while that of mercury was a little lower. Overall, there was no significant difference in the distribution of heavy metal levels in the blood among age groups. Additionally, the investigation of the perceived damage from municipal waste incinerators showed that the subjects
Показать больше [+] Меньше [-]Abundance and diversity of Sphingomonas in Shenfu petroleum-wastewater irrigation zone, China
2012
Zhou, Lisha | Li, Hui | Zhang, Ying | Wang, Yafei | Han, Siqin | Xu, Hui
INTRODUCTION: Members of the genus Sphingomonas have raised increasing attention due to their ability for polycyclic aromatic hydrocarbon (PAH) degradation and their ubiquity in the environment. However, few studies have revealed the ecological information on the abundance and diversity of Sphingomonas in the environment. MATERIALS AND METHODS: A primer set targeting the Sphingomonas 16S rRNA gene was designed. The specificity was tested with four petroleum-contaminated soils by construction of clone libraries and further restriction fragment length polymorphism analysis. Subsequently, real time PCR and denaturing gradient gel electrophoresis (DGGE) assays were used to evaluate the abundance and diversity of Sphingomonas in the Shenfu irrigation zone, China. RESULTS: A genus-specific primer set SA/429f-933r was developed, and 90% of the sequences retrieved from soil clone libraries were related to Sphingomonas. Members of the genus Sphingomonas were detected in all soils, and significant correlation (p < 0.05) was observed between the Sphingomonas abundance and the ratios of PAHs to total petroleum hydrocarbon (TPH). DGGE profiles revealed Sphingomonas population structures differed greatly in different sites. The Sphingomonas diversity was not statistically (p > 0.05) correlated with the contamination level. Some of the soil-derived sequences were not grouped phylogenetically with sequences of known Sphingomonas, indicating new members of the Sphingomonas genus might be present in the Shenfu irrigation zone. CONCLUSION: The newly designed Sphingomonas-selective primers were specific and practicable for analyzing Sphingomonas abundance and diversity in petroleum-contaminated soils. The significant correlation between the abundance and the ratios of PAHs to TPH suggested an important role of Sphingomonas in PAH bioremediation.
Показать больше [+] Меньше [-]Novel insights in Al-MCM-41 precursor as adsorbent for regulated haloacetic acids and nitrate from water
2012
Bruzzoniti, Maria Concetta | De Carlo, Rosa Maria | Sarzanini, Corrado | Caldarola, Dario | Onida, Barbara
High concentration of NO 3 − in groundwater has raised concern over possible contamination of drinking water supplies. In addition, the formation of haloacetic acids (HAAs) as by-products during disinfection with chlorine-based agents is still a relevant issue, since HAAs pose serious health hazard. In this work, we investigated the affinity of a precursor of Al-MCM-41 (a mesostructured hexagonal aluminosilicate containing the template surfactant) towards nitrate and HAAs, for its possible application in the removal of these pollutants from natural and drinking waters. Additionally, adsorption kinetics and isotherms were studied. The adsorbent was synthesized using cetyltrimethylammonium bromide as surfactant and characterized by physico–chemical techniques. Simulated drinking water was spiked with the EPA-regulated HAAs (monochloroacetic (MCAA), monobromoacetic (MBAA), dichloroacetic (DCAA), dibromoacetic (DBAA), and trichloroacetic (TCAA) acids) and placed in contact with the adsorbent. The effect of matrix composition was studied. Adsorption kinetic studies were performed testing three kinetics models. For the adsorption studies, three adsorption isotherm approaches have been tested to experimental data. The pollutant recoveries were evaluated by suppressed ion chromatography. The affinity of the adsorbent was TCAA = DBAA = DCAA > MBAA > MCAA with DCAA, DBAA, and TCAA completely removed. A removal as high as 77 % was achieved for 13 mg/L nitrate. The adsorption isotherms of NO 3 − and monochloroacetic acid can be modeled by the Freundlich equation, while their adsorption kinetics follow a pseudo-second-order rate mechanism. The adsorbent exhibited high affinity towards HAAs in simulated drinking water even at relevant matrix concentrations, suggesting its potential application for water remediation technologies.
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