خيارات البحث
النتائج 1681 - 1690 من 3,991
A Two-Step Approach to Eliminate Pesticides and Estrogens from a Wastewater and Reduce Its Phytotoxicity: Adsorption onto Plant-Derived Materials and Fungal Degradation
2016
Loffredo, Elisabetta | Castellana, Giancarlo | Taskin, Eren
In this study, adsorption and biodegradation were exploited sequentially to remove the herbicide fenuron, the insecticide carbaryl and the estrogens 17β-estradiol (E2) and 4-tert-octylphenol (OP) from a municipal landfill leachate (MuLL). In the first step, we used spent coffee grounds, almond shells, a biochar and potato dextrose agar to adsorb the compounds spiked in MuLL at a concentration of 1 mg L⁻¹. After only 3 days, any adsorbent removed from MuLL the totality of E2 and OP, averagely more than 95 % of carbaryl and 62 % of fenuron (81 % after 7 days). In the second step, the adsorbents collected from MuLL after 7 days were inoculated with the fungi Bjerkandera adusta and Irpex lacteus, separately. After 7 days, the maximum degradation occurred for OP in any treatment being averagely 78 and 74 % using B. adusta and I. lacteus, respectively. After 15 days, the average percentages of fenuron, carbaryl, E2 and OP degraded were, respectively, 75, 76, 88 and 88 % using B. adusta, and 74, 79, 85 and 89 % using I. lacteus. Residual estrogenicity in the adsorbents, tested with the recombinant yeast assay, was strictly related to residual E2, thus indicating a negligible contribution from the other contaminants and/or degradation products. The 7-day treatment of MuLL with the adsorbents caused a significant abatement of MuLL phytotoxicity on flax (2.5 times seedling elongation with coffee grounds, compared to MuLL) and a huge stimulation of rapeseed respect to water (biomass almost doubled), thus suggesting a possible worthwhile recycling of this wastewater in agriculture.
اظهر المزيد [+] اقل [-]Fenced cultivation of water hyacinth for cyanobacterial bloom control
2016
Qin, Hongjie | Zhang, Zhiyong | Liu, Haiqin | Li, Dunhai | Wen, Xuezheng | Zhang, Yingying | Wang, Yan | Yan, Shaohua
To achieve the goals of harmful cyanobacterial bloom control and nutrient removal, an eco-engineering project with water hyacinth planted in large-scale enclosures was conducted based on meteorological and hydrographical conditions in Lake Dianchi. Water quality, cyanobacteria distribution, and nutrient (TN, TP) bioaccumulation were investigated. Elevated concentrations of N and P and low Secchi depth (SD) were relevant to large amount of cyanobacteria trapped in regions with water hyacinth, where biomass of the dominant cyanobacteria Microcystis (4.95 × 10¹⁰ cells L⁻¹) was more than 30-fold compared with values of the control. A dramatic increase of TN and TP contents in the plants was found throughout the sampling period. Results from the present study confirmed the great potential to use water hyacinth for cyanobacterial bloom control and nutrient removal in algal lakes such as Lake Dianchi.
اظهر المزيد [+] اقل [-]The Accumulation Potency of Bulk and Nano Zinc Metal and Their Impacts on the Hematological and Histological Perturbations of Oreochromis niloticus
2016
Abdel-Khalek, Amr Adel | Hamed, Aliaa | Marie, Mohamed-Assem
This study was carried out to comparatively evaluate the bioaccumulation potency of Zn bulk and nanoparticles in Oreochromis niloticus and to investigate the induced hematological and histological alterations. Fish were exposed to ½ LC50/96 h values of both bulk and nano Zn meal for 7, 14, and 28 days. Concerning metal bioaccumulation factor (BAF), the data displayed that zinc nanoparticles (Zn NPs) had more efficiency to penetrate the studied tissues such as the liver, kidneys, gills, skin, and muscle. Hematological parameters named red blood cells (RBC), hemoglobin (Hb), and hematocrit (Hct) values were altered in Zn NPs treated groups after 14th and 28th days while these hematological parameters recovered to some extent in bulk particles (BPs) treated groups at the end of the experimental period. The changes in hematological parameters were found to be time dependent. Blood indices such as mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) revealed the presence of normocytic normochromic anemia in the studied groups at the most exposure periods except microcytic hypochromic anemia at the 7th day of bulk particles exposed fish. Based on histological end points, several alterations in the gills, liver, and kidney tissues were observed. Severely deformations were observed at NPs treated fish groups which varied between adaptive changes to tissue damage at the end of exposure period. The deformations were recorded to be increased in NPs exposed fish compared to BPs treated fish throughout the study periods.
اظهر المزيد [+] اقل [-]Toward a Cost-Efficient Method for Monitoring of Traffic-Derived Pollutants with Quartz Sand Boxes
2016
Ojha, Gobinda | Appel, Erwin | Wawer, Małgorzata | Magiera, Tadeusz | Hu, Shouyun
This study aims at understanding characteristics of current traffic pollution at roadsides and to assess the use of magnetic parameters for a cost-efficient monitoring concept. We conducted a systematic monitoring study of roadside pollution at three sites in southern Germany and one site at Lanzhou/China. For this purpose, we installed ground-based monitoring boxes filled with clean quartz sand at different distances (1, 2, and 4 m) from the road. Mass-specific magnetic susceptibility (χ), heavy metal (HM) contents, and polycyclic aromatic hydrocarbon (PAH) concentrations all showed decreasing values with distance to the roadside. The temporal variations over 2 years of monitoring reveal an overall increasing trend but differences in depth migration due to seasonal effects (i.e., precipitation). A magnetite-like phase turned out to be responsible for the enhancement of χ. Significant positive correlations between χ and total PAHs as well as HMs for the German sites suggest that χ—which can be measured fast and convenient—can be used as a proxy for traffic-derived PAH and HM pollution. However, in the much drier region of Lanzhou, the relationship of χ with HMs is much weaker, which might be caused by specific materials used in road construction and heavy vehicles. From the obtained results, we conclude that an appropriate roadside monitoring procedure based on magnetic signatures should best use a single thin (1–2 cm) layer of clean quartz sand protected against lateral material translocation.
اظهر المزيد [+] اقل [-]Traits Driving Tolerance to Atmospheric Fluoride Pollution in Tree Crops
2016
Mesquita, Geisa Lima | Mattos, Dirceu, Jr | Tanaka, Francisco A Ossamo | Cantarella, Heitor | Zambrosi, Fernando C Bachiega | Machado, Eduardo Caruso
Increased emissions of fluoride into the atmosphere contribute to reducing the sustainability of agricultural systems worldwide. In order to improve the understanding of the factors behind such phenomenon, varieties of citrus (Citrus spp.), Valencia sweet-orange, Ponkan mandarin, and Lisbon lemon and coffee (Coffea spp.), Obatã, Catuai, and Apoatã, were treated with fluoride nebulization. The trees were exposed to nebulization for 60 min inside a chamber by using medium (0.04 mol L⁻¹) and high (0.16 mol L⁻¹) doses of fluoridic acid (HF) during three nonconsecutive days in a single week, for a total of 26 days of exposure during the experiment. Sixty days after beginning nebulization, we evaluated leaf gas exchange, (ultra)structural organization, tree growth, and fluoride and nutrient concentrations in plant tissue. Photosynthesis and leaf dry mass of citrus and coffee varieties were affected differently by fluoride toxicity, and based on the tolerance index (relative leaf dry mass of control versus leaf dry mass of trees treated with 0.16 mol L⁻¹ HF), the order of sensitivity for the varieties of each species was as follows: for citrus, lemon > mandarin > sweet-orange; and for coffee, Apoatã > Catuaí > Obatã. The ability of the trees to control fluoride absorption most likely explained this contrast in sensitivity among varieties because both photosynthesis and leaf growth were negatively correlated with leaf fluoride concentration. Although disorganization of the thylakoids, degeneration of vascular cells, and disruption of the middle lamella occurred in leaves of all varieties exposed to fluoride, the more severe damage was observed in those with greater sensitivity to the pollutant (i.e., lemon and Apoatã coffee). Taken together, these results provided insights into the factors that explain poor performance of citrus and coffee trees under fluoride pollution and also revealed the traits driving the tolerance of these crops such a limiting condition, which included a combination of the following: (i) reduced fluoride absorption, (ii) increased photosynthesis, and (iii) improved maintenance of the ultrastructural organization of leaves.
اظهر المزيد [+] اقل [-]Toxicity of Engineered Nickel Oxide and Cobalt Oxide Nanoparticles to Artemia salina in Seawater
2016
Ateş, Mehmet | Demir, Veysel | Arslan, Zikri | Camas, Mustafa | Celik, Fatih
In this study, the effects of exposure to engineered nickel oxide (NiO 40–60 nm) and cobalt oxide (CoO <100 nm) nanoparticles (NP) were investigated on Artemia salina. Aggregation and stability of the aqueous NP suspensions were characterized by DLS and TEM. Acute exposure was conducted on nauplii (larvae) in seawater in a concentration range from 0.2 to 50 mg/L NPs for 24 h (short term) and 96 h (long term). The hydrodynamic diameters of NiO and CoO NPs in exposure medium were larger than those estimated by TEM. Accumulation rate of NiO NPs were found to be four times higher than that of CoO NPs under the same experimental conditions. Examinations under phase contrast microscope showed that the nanoparticles accumulated in the intestine of Artemia, which increased with increasing exposure concentration. Differences were observed in the extent of dissolution of the NPs in the seawater. The CoO NPs dissolved significantly while NiO NPs were relatively more stable. Oxidative stress induced by the NP suspensions was measured by malondialdehyde assay. Suspensions of NiO NPs caused higher oxidative stress on nauplii than those of CoO NPs. The results imply that CoO and NiO NPs exhibit toxicity on Artemia (e.g., zooplankton) that is an important source of food in aquatic food chain.
اظهر المزيد [+] اقل [-]Mutagenic properties of linuron and chlorbromuron evaluated by means of cytogenetic biomarkers in mammalian cell lines
2016
Federico, Concetta | Palmieri, Cristina | Pappalardo, Anna Maria | Ferrito, Venera | Pappalardo, Matteo | Librando, V. (Vito) | Saccone, Salvatore
Agricultural practices are usually supported by several chemical substances, such as herbicides. Linuron and chlorbromuron are phenylurea herbicides largely used to protect crops from weeds, blocking photosynthesis by inhibition of the photosystem II complex. The former, also commercially known as lorox or afalon, is selectively used to protect bean and French bean plants, fennels, and celeriacs; the second, commercially known as maloran, is selectively used for carrots, peas, potatoes, soy sprouts, and sunflowers. Considering the widespread use of herbicides and, more generally, pesticides, it is important to clarify their involvement on human health, one of them concerning the possible direct or indirect effect on the genome of exposed populations. Here, we show that these herbicides are endowed by mutagenic properties, as demonstrated by an increased number of chromosomal aberrations (CAs) in two exposed Chinese hamster cell lines derived from ovary and epithelial liver, respectively. This was also confirmed by sister chromatid exchange (SCE) and micronucleus (MN) assays. Our present and previously obtained data clearly indicate that phenylurea herbicides must be used with great caution, especially for agricultural workers who use large amounts of herbicides during their work, and particular attention should be given to residues of these herbicides and their involvement in environmental pollution.
اظهر المزيد [+] اقل [-]Effects of benzo[a]pyrene as an environmental pollutant and two natural antioxidants on biomarkers of reproductive dysfunction in male rats
2016
Sheweita, Salah A. | Al-Shora, S. | Hassan, M.
Benzo[a]pyrene (B[a]P) is an environmental toxicant and endocrine disruptor. Therefore, the aim of the present study was to investigate the toxicity of B[a]P in testis of rats and also to study the role of silymarin and thymoquinone (TQ) as natural antioxidants in the alleviation of such toxicity. Data of the present study showed that levels of testosterone, estrogen and progesterone were significantly decreased after treatment of rats with B[a]P. In addition, B[a]P caused downregulation of the expressions of steroidogenic enzymes including CYP17A1 and CP19A1, and decreased the activity of 17-β hydroxysteroid dehydrogenase (17β-HSD). Moreover, B[a]P decreased the activities of antioxidant enzymes including catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD), and significantly increased free radicals levels in testis of male rats. However, pretreatment of rats with silymarin prior to administration of B[a]P was found to restore the level of free radicals, antioxidant status, and activities of steroidogenic enzymes to their normal levels in testicular tissues. Moreover, histopathological finding showed that silymarin recovered the abnormalities occurred in tubules caused by B[a] P in testis of rats. On the other hand, TQ showed pro-oxidant effects and did not ameliorate the toxic effects of B[a] P on the testicular tissue since it decreased antioxidant enzymes activities and inhibited the protein expression of CYP11A1 and CYP21A2 compared to control rats. Moreover, TQ decreased the levels of testosterone, estrogen, and progesterone either in the presence or absence of B[a]P. It is concluded that B[a]P decreased testosterone levels, inhibited antioxidant enzymes activities, caused downregulation of CYP isozymes involved in steroidogenesis, and increased free radical levels in testis. Moreover, silymarin was more effective than TQ in restoring organism health and alleviating the deleterious effects caused by B[a]P in the testis of rats. Due to its negative impact, it is highly recommended to limit the use of TQ as a dietary supplement since millions of people in the Middle East are using it to improve their health.
اظهر المزيد [+] اقل [-]Occurrence and Sources of Polycyclic Aromatic Hydrocarbons in the Tisza River and its Romanian Tributaries
2016
Beldean-Galea, Mihail Simion | Mihăiescu, Radu | Arghiuş, Viorel | Croitoru, Adina | Horváth, Csaba | Coman, Virginia
The aim of this work is to assess the occurrence of Polycyclic aromatic hydrocarbons (PAHs) in the Tisza River and its main Romanian tributaries (Vişeu River and Iza River) and to establish the origin (pyrogenic/petrogenic) of pollution sources. Fifteen PAHs were investigated in surface water and sediment samples collected from three selected sampling point. The target compounds were isolated from the matrices by solid phase extraction for water samples and by ultrasound-assisted extraction for the sediment samples, respectively. The quantification of the target compounds was performed by HPLC coupled with a fluorescence detector. PAH diagnostic ratios, as the abundance ratio of 2–3 ring hydrocarbons to 4–6 ring hydrocarbons (LMW/HMW), ANT/(ANT + PHE), FLT/(FLT + PYR), B[a]A/(B[a]A + CHR), and IND/(IND+ B[g,h,i]P) were used as a tool for identification and assessment of the pollution emission sources. The results of the study showed that in the studied area, the total concentrations of PAHs detected in water samples ranged from 1.22 to 260.26 ng L⁻¹, while those in sediment samples varied from 4.94 to 10.62 μg kg⁻¹. Regarding the PAH pattern, mixed sources of pollution (pyrogenic and petrogenic) occur in both water and sediment samples. Thus, leaks of petroleum products and biomass, coal, and petroleum combustion are the main sources of pollution identified into the studied area.
اظهر المزيد [+] اقل [-]Monitoring of polycyclic aromatic hydrocarbons in a produced water disposal area in the Potiguar Basin, Brazilian equatorial margin
2016
Lourenço, Rafael André | de Oliveira, Fábio Francisco | de Souza, João Maximino | Nudi, Adriana Haddad | de Luca Rebello Wagener, Ângela | de Fátima Guadalupe Meniconi, Maria | Francioni, Eleine
The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through submarine outfalls. Although polycyclic aromatic hydrocarbons (PAHs) are minor constituents of PW, their input into the marine ecosystem is environmentally critical due to potential ecological hazards. A 2-year monitoring program was conducted in the vicinity of the outfalls to evaluate PAH bioaccumulation in marine life from PW discharges. The study was performed using transplanted bivalves Crassostrea brasiliana and semipermeable membrane devices (SPMDs) to measure PAH concentrations via bioaccumulation and in seawater. The bioaccumulation of PAH in transplanted bivalves reached up to 1105 ng g⁻¹ in the vicinity of the monitored outfall. Significantly lower PAH concentrations were found in the reference area in comparison to the studied area around the outfalls. Time-integrated PAH concentrations in seawater ranged from 38 to 0.3 ng L⁻¹ near the outfalls and from 10 ng L⁻¹ to not detected in the reference area. Both measurement techniques were found to be effective for determining a gradient of descending PAH concentrations from the outfalls. In addition, this study also evaluated the bioavailability of PAH for local marine biota and provided information about the influence of PW discharges on the water quality of marine ecosystems.
اظهر المزيد [+] اقل [-]