خيارات البحث
النتائج 2921 - 2930 من 4,308
Evaluation of cotton burdock (Arctium tomentosum Mill.) responses to multi-metal exposure النص الكامل
2017
AL Harbawee, Waad E. Q. | Kluchagina, Alina N. | Anjum, Naser A. | Bashmakov, Dmitry I. | Lukatkin, Alexander S. | Pereira, Eduarda
Plants have immense potential for their use in the minimization of emerging environmental pollution issues. Under simulated laboratory conditions, this work investigated the growth and biochemical responses of 14-day-old cotton burdock (Arctium tomentosum Mill.) seedlings to the body burdens of multi-metals including Pb, Cu, Ni, and Zn (1.0 μM–10 mM). Biochemical traits (superoxide generation, lipid peroxidation, content of total peroxides), growth traits (axial organs growth, dry weight accumulation, leaf area), and also metal body burdens varied with types and concentrations of metals. Results indicated a significant tolerance of A. tomentosum to multi-metals that can be implicated for its potential role in the metal phytoremediation programs.
اظهر المزيد [+] اقل [-]Enhanced degradation of BDE209 in spiked soil by ferrous-activated persulfate process with chelating agents النص الكامل
2017
Peng, Hongjiang | Xu, Liya | Zhang, Wei | Liu, Lin | Liu, Fuwen | Lin, Kuangfei | Lu, Qiang
In order to maintain the quantity of ferrous ions, two eco-friendly chelating agents (CAs), i.e., sodium citrate (Citrate) and sodium gluconate (Glu), have been introduced into a traditional iron activated sodium persulfate (PS) system (Fe²⁺/PS). The results indicated that the PS/CA/Fe²⁺ oxidation could be an effective method for BDE209 removal. Effects of the chelating agents, reagents dosage, and pH were evaluated in batch experiments. Glu was observed to be more effective than citrate. In addition, the rate constants (k ₁) of BDE209 removal indicated a quadratic curve relationship with initial persulfate concentrations (k ₁ = −0.019 × [PS]₀ ² + 0.031 × [PS]₀ + 0.007, R ² = 0.933, [PS]₀ = 0.1–1.0 M) and a good linear relationship with initial ferrous contents (k ₁ = 0.109 × [Fe²⁺]₀ + 0.002, R ² = 0.943). Furthermore, as a reducing agent, ascorbic acid (H₂A) could enhance the degradation rate of BDE209, which might be because H₂A accelerated the transformation process from Fe³⁺- to Fe²⁺-gluconate complexes.
اظهر المزيد [+] اقل [-]Cleaner processing: a sulphide—free approach for depilation of skins النص الكامل
2017
Ranjithkumar, Ammasi | Durga, Jayanthi | Ramesh, Ramakrishnan | Rose, Chellan | Muralidharan, Chellappa
The conventional unhairing process in leather making utilises large amount of lime and sodium sulphide which is hazardous and poses serious waste disposal concerns. Under acidic conditions, sodium sulphide liberates significant quantities of hydrogen sulphide which causes frequent fatal accidents. Further, the conventional unhairing process involves destruction of the hair leading to increased levels of biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS) and total suspended solids (TSS) in the effluent. A safe approach is needed to overcome such environmental and health problems through an eco-benign process. The present study deals with a clean technology in which the keratinous body is detached from the dermis using enzymes produced from Bacillus crolab MTCC 5468 by solid state fermentation (SSF) as an alternative to noxious chemicals. Complete unhairing of skin could be achieved with an enzyme concentration of 1.2 % (w/w). The bio-chemical parameters of the spent liquor of the enzymatic process were environmentally favourable when compared with conventional method. The study indicates that the enzymatic unhairing is a safe process which could be used effectively in leather processing to alleviate pollution and health problems.
اظهر المزيد [+] اقل [-]Dental health status in crack/cocaine-addicted men: a cross-sectional study النص الكامل
2017
Cury, Patricia R. | Oliveira, Maria G. A. | de Andrade, Katia Montanha | de Freitas, Maíra D. S. | dos Santos, Jean N.
The aim of this study was to evaluate the association between crack/cocaine addiction and dental health in men. Forty crack/cocaine-addicted patients and 120 nonaddicted patients (≥18 years) underwent full-mouth dental examinations. Decayed, missing, and filled teeth (DMFT) were identified using the criteria recommended by the World Health Organization. Crack/cocaine addiction was determined, based on the medical records and interviews of each patient. All drug-addicted patients used both crack and cocaine. The chi-square test and logistic regression analysis were used to assess the association between DMFT and crack/cocaine addiction (p ≤ 0.05). Decayed teeth showed a positive association with crack/cocaine addiction (odds ratio (OR) = 3.65; 95% confidence interval (CI), 1.68–7.92; p = 0.001), whereas filled and missing teeth showed a negative association (filled teeth: OR = 0.37; 95% CI, 0.18–0.76; p = 0.008; missing teeth: OR = 0.33; 95% CI, 0.13–0.81; p = 0.02). The DMFT was only associated with age (OR = 2.12; 95% CI, 1.11–4.08, p = 0.023). In the present population, crack/cocaine addiction was associated with a greater decayed teeth index and a lower filled and missing teeth index. Programs aimed to encourage self-esteem and encourage individuals to seek dental care are required for this population. Further studies using a larger sample size and studies with women are required to confirm the results.
اظهر المزيد [+] اقل [-]Congenital malformations according to etiology in newborns from the floricultural zone of Mexico state النص الكامل
2017
Castillo-Cadena, Julieta | Mejia-Sanchez, Fernando | Amado López Arriaga, Jerónimo
Birth defects are the number one cause of child mortality worldwide and in 2010 it was the second cause in Mexico. Congenital malformations are a public health issue, because they cause infant mortality, chronic disease and disability. The origin can be genetic, environmental or unknown causes. Among environmental contaminants, pesticides stand out. In this study, we determine the frequency and etiology of congenital malformations in newborns (NBs) of a floricultural community and we compare it with that in the urban community. For 18 months, the NBs were monitored at the Tenancingo General Hospital and the Mother and Child Gynecology and Obstetrics Hospital (IMIEM) in Toluca. The identification of these malformations was carried out in accordance with the WHO. In Tenancingo, 1149 NBs were viewed, where 20% had some kind of congenital malformations. While in the IMIEM, 5069 were reviewed and 6% had some malformation. According to the etiology, in Tenancingo, 69% were multifactorial, 28% were monogenetic and 2% were chromosomal. In the IMIEM, 47% were multifactorial, then 18.3% were monogenetic and 2.8% were chromosomal. There was a significant difference between the global frequency of malformations and the multifactorial etiology of both institutions. Our results show that congenital malformations in the NBs occurred more frequently in the floricultural zone and that because the percentage of multifactorial etiology is higher, it is likely there is an association with exposure to pesticides.
اظهر المزيد [+] اقل [-]The importance of environmental factors and matrices in the adsorption, desorption, and toxicity of butyltins: a review النص الكامل
2017
Fang, Liping | Xu, Cuihong | Li, Ji | Borggaard, Ole K. | Wang, Dongsheng
Butyltins (BTs) are considered as a group of the most important organometallic compounds in industry and agriculture. Due to their widespread use, large amounts of BTs including tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) have entered into the environment, and subsequently causing detrimental effects on humans and aquatic organisms. This work provides a critical review of recent studies on the adsorption, desorption, bioaccumulation, and toxicity of BTs that can notably influence the distribution of BTs in the environment. Influence of environmental factors (e.g., pH and salinity) and adsorbents in the matrices (e.g., minerals, organic carbons, and quartz) on the adsorption, desorption, and toxicity of BTs is particularly addressed.
اظهر المزيد [+] اقل [-]Histological and biochemical biomarkers analysis reveal strong toxicological impacts of pollution in hybrid sparrow (Passer domesticus × Passer hispaniolensis) in southern Tunisia النص الكامل
2017
Amri, Nahed | Rahmouni, Fatma | Chokri, Med Ali | Rebai, Tarek | Badraoui, Riadh
Environmental pollution is a great concern worldwide. Our aim was to investigate the histopathological injuries and oxidative stress induced by exposure to contaminants in liver tissues of hybrid sparrows (Passer domesticus × Passer hispaniolensis) living in Gabès city, which is one of the most polluted hot spot in Tunisia. Our results show evidence of a pronounced impairment in liver function which is confirmed by histopathological changes as well as remarkable blood chemical alterations in sparrows living near the Gabès–Ghannouche factory complex of phosphate treatment. Moreover, a significant decrease in the hepatic activities of superoxide dismutase (SOD) and catalase (CAT) was observed in birds from Ghannouche when compared to other distant areas. Our study revealed also a significant increase in the liver levels of thiobarbituric acid reactive substances (TBARS), in sparrows living in Ghannouche, indicating oxidative damage to membrane lipids. Overall, our results suggest that the hybrid sparrow offers a suitable model for biomonitoring programs of atmosphere pollutants and the selected biomarkers may function as useful tool to evaluate the effects of pollutants on living organisms.
اظهر المزيد [+] اقل [-]Effects of nanoparticles in species of aquaculture interest النص الكامل
2017
Khosravi-Katuli, Kheyrollah | Prato, Ermelinda | Lofrano, Giusy | Guida, Marco | Vale, Gonçalo | Libralato, Giovanni
Recently, it was observed that there is an increasing application of nanoparticles (NPs) in aquaculture. Manufacturers are trying to use nano-based tools to remove the barriers about waterborne food, growth, reproduction, and culturing of species, their health, and water treatment in order to increase aquaculture production rates, being the safe-by-design approach still unapplied. We reviewed the applications of NPs in aquaculture evidencing that the way NPs are applied can be very different: some are direclty added to feed, other to water media or in aquaculture facilities. Traditional toxicity data cannot be easily used to infer on aquaculture mainly considering short-term exposure scenarios, underestimating the potential exposure of aquacultured species. The main outputs are (i) biological models are not recurrent, and in the case, testing protocols are frequently different; (ii) most data derived from toxicity studies are not specifically designed on aquaculture needs, thus contact time, exposure concentrations, and other ancillary conditions do not meet the required standard for aquaculture; (iii) short-term exposure periods are investigated mainly on species of indirect aquaculture interest, while shrimp and fish as final consumers in aquaculture plants are underinvestigated (scarce or unknown data on trophic chain transfer of NPs): little information is available about the amount of NPs accumulated within marketed organisms; (iv) how NPs present in the packaging of aquacultured products can affect their quality remained substantially unexplored. NPs in aquaculture are a challenging topic that must be developed in the near future to assure human health and environmental safety. Graphical abstract ᅟ
اظهر المزيد [+] اقل [-]Distribution and health risk assessment of dissolved heavy metals in the Three Gorges Reservoir, China (section in the main urban area of Chongqing) النص الكامل
2017
Zhao, Xin | Li, Ting-Yong | Zhang, Tao-Tao | Luo, Wei-Jun | Li, Jun-Yun
The Three Gorges Project (TGP) is the largest hydropower station ever built in the world. A better understanding of the concentrations of heavy metals in the aquatic environment of the Three Gorges Reservoir (TGR) is crucial for national drinking water security and sustainable ecosystem development. To thoroughly investigate the impact of heavy metals on water quality after the impoundment to the maximum level of 175 m in the TGR, the concentrations of the dissolved heavy metals (Cr, Cu, Zn, Cd, Pb, As) were measured in April and August 2015, by inductively coupled plasma mass spectrometry (ICP-MS). (1) Except Zn and Pb, most of the heavy metal concentrations in the water of the TGR reached the level of the National Surface Water Environmental Quality Standards (GB3838-2002) I of China, revealing that the water quality of the TGR was good overall. (2) There were significant positive correlations among the concentrations of Cu, As, and Cd, revealing that they may exhibit similar geochemical behaviors. (3) The spatial distribution of the heavy metal concentrations was diverse and complex. The Zn concentration obviously increased in the rainy season from upstream to downstream in the Yangtze River, while the other heavy metals exhibited no significant changes in their concentrations. The distribution characteristics of the heavy metal concentrations on both sides and the middle of the river were different at different sites. (4) The health risk of the six elements was assessed through a human health risk assessment (HHRA), and the assessment results were lower than the maximum acceptable risk level designed by the US EPA and International Commission on Radiological Protection (ICRP). The HHRA model in the aquatic environment revealed that the risk of non-carcinogenic heavy metals (Cu, Zn, and Pb) was at a negligible risk level of 10⁻¹¹∼10⁻⁹ a⁻¹. At all the study sites, the risk of carcinogenic heavy metals (Cr, Cd, and As) was higher than the risk of non-carcinogenic heavy metals. As was the most important risk factor, followed by Cr. The results of this study hold great significance for a timely understanding of the changing water quality for affected departments to ensure the health of the residents in the TGR area.
اظهر المزيد [+] اقل [-]Distribution of total mercury and methylmercury around the small-scale gold mining area along the Cikaniki River, Bogor, Indonesia النص الكامل
2017
Tomiyasu, Takashi | Kodamatani, Hitoshi | Hamada, Yuriko Kono | Matsuyama, Akito | Imura, Ryusuke | Taniguchi, Yoko | Hidayati, Nuril | Rahajoe, Joeni Setijo
This study investigates the distribution of total mercury (T-Hg) and methylmercury (MeHg) in the soil and water around the artisanal and small-scale gold mining (ASGM) area along the Cikaniki River, West Java, Indonesia. The concentration of T-Hg and MeHg in the forest soil ranged from 0.07 to 16.7 mg kg⁻¹ and from <0.07 to 2.0 μg kg⁻¹, respectively, whereas it ranged from 0.40 to 24.9 mg kg⁻¹ and from <0.07 to 56.3 μg kg⁻¹, respectively, in the paddy field soil. In the vertical variation of the T-Hg of forest soil, the highest values were observed at the soil surface, and these values were found to decrease with increasing depth. A similar variation was observed for MeHg and total organic carbon content (TOC), and a linear relationship was observed between them. Mercury deposited on the soil surface can be trapped and retained by organic matter and subjected to methylation. The slope of the line obtained for the T-Hg vs. TOC plot became larger near the ASGM villages, implying a higher rate of mercury deposition in these areas. In contrast, the plots of MeHg vs. TOC fell along the same trend line regardless of the distance from the ASGM village. Organic carbon content may be a predominant factor in controlling MeHg formation in forest soils. The T-Hg concentration in the river water ranged from 0.40 to 9.6 μg L⁻¹. River water used for irrigation can prove to be a source of mercury for the paddy fields. The concentrations of Hg⁰ and Hg²⁺ in river water showed similar variations as that observed for the T-Hg concentration. The highest Hg⁰ concentration of 3.2 μg L⁻¹ can be attributed to the waste inflow from work sites. The presence of Hg⁰ in river water can become a source of mercury present in the atmosphere along the river. MeHg concentration in the river water was found to be 0.004–0.14% of T-Hg concentration, which was considerably lower than the concentrations of other Hg species. However, MeHg comprised approximately 0.2% of the T-Hg in paddy field soil. Mercury deposited from the atmosphere and the river water can be subjected to methylation. Paddy fields are very important ecosystems; therefore, the effect of MeHg on these ecosystems and human beings should be further investigated.
اظهر المزيد [+] اقل [-]