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Chlordecone exposure and adverse effects in French West Indies populations Texto completo
2016
Multigner, Luc | Kadhel, Philippe | Rouget, Florence | Blanchet, Pascal | Cordier, Sylvaine
Chlordecone (Kepone) is an organochlorine insecticide that has been used as insecticide and fungicide. In the French West Indies, Guadeloupe and Martinique, it was intensively applied to banana fields from 1973 to 1993 to control root borers. This pesticide undergoes no significant biotic or abiotic degradation in the environment and is still present in soils where it was applied. It was only in 1999 that health and environmental authorities became aware of the extent of the chlordecone pollution of environmental media, including soils, waterways, and the food chain. Earlier observations and toxicological studies have demonstrated that chlordecone is a reproductive and developmental toxicant, neurotoxic and carcinogenic in rodents, and is an endocrine-disrupting chemical because of its estrogenic properties both in vitro and in vivo. Several surveys have confirmed that the French West Indian population continues to be exposed to this chemical though consumption of contaminated foodstuffs. Here, we report the findings of various epidemiological studies conducted in the French West Indies to assess the impact of environmental exposure to chlordecone on the health of the population.
Mostrar más [+] Menos [-]Carbon emissions, logistics volume and GDP in China: empirical analysis based on panel data model Texto completo
2016
Guo, Xiaopeng | Ren, Dongfang | Shi, Jiaxing
This paper studies the relationship among carbon emissions, GDP, and logistics by using a panel data model and a combination of statistics and econometrics theory. The model is based on the historical data of 10 typical provinces and cities in China during 2005–2014. The model in this paper adds the variability of logistics on the basis of previous studies, and this variable is replaced by the freight turnover of the provinces. Carbon emissions are calculated by using the annual consumption of coal, oil, and natural gas. GDP is the gross domestic product. The results showed that the amount of logistics and GDP have a contribution to carbon emissions and the long-term relationships are different between different cities in China, mainly influenced by the difference among development mode, economic structure, and level of logistic development. After the testing of panel model setting, this paper established a variable coefficient model of the panel. The influence of GDP and logistics on carbon emissions is obtained according to the influence factors among the variables. The paper concludes with main findings and provides recommendations toward rational planning of urban sustainable development and environmental protection for China.
Mostrar más [+] Menos [-]Effects of perchlorate bioaccumulation on Spodoptera litura growth and sex ratio Texto completo
2016
Qin, Junhao | Shu, Yinghua | Li, Yongjun | He, Hongzhi | Li, Huashou
Perchlorate (ClO₄ ⁻) pollution is widespread in the natural environment, but the effects of ClO₄ ⁻ on the terrestrial insects are rarely studied. Here, when phytophagous insect Spodoptera litura larvae were fed on the diets with different ClO₄ ⁻ concentrations, changes in their life-history traits were recorded; ClO₄ ⁻ accumulations in feces and insect body were detected. The results demonstrated that ClO₄ ⁻ bioaccumulation in insect at the different developmental stages was ranked in the order: adults > pupae > the 4th > 5th > 6th instar larvae. Besides, ClO₄ ⁻ accumulations in the feces were ranked in the order: the 6th > 5th > 4th instar larvae. The ClO₄ ⁻ accumulations in female pupae and adults were significantly higher than that in males. ClO₄ ⁻ bioaccumulation in insect prolonged larval development time and caused a skewed sex ratio (the percentage of males at metamorphosis significantly decreased) under 100 to 200 mg ClO₄ ⁻/kg treatment. Therefore, ClO₄ ⁻ accumulations in S. litura body presented developmental stage-, sex-specific pattern, and the sex-specific ClO₄ ⁻ accumulations resulted in difference of sex ratio. These effects were observed at concentrations reported in natural environments contaminated with ClO₄ ⁻, suggesting that this contaminant may pose a threat to the normal development and growth of this insect species.
Mostrar más [+] Menos [-]Effects of alkaline and bioorganic amendments on cadmium, lead, zinc, and nutrient accumulation in brown rice and grain yield in acidic paddy fields contaminated with a mixture of heavy metals Texto completo
2016
He, Huaidong | Tam, Nora F. Y. | Yao, Aijun | Qiu, Rongliang | Li, Wai Chin | Ye, Zhihong
Paddy soils and rice (Oryza sativa L.) contaminated by mixed heavy metals have given rise to great concern. Field experiments were conducted over two cultivation seasons to study the effects of steel slag (SS), fly ash (FA), limestone (LS), bioorganic fertilizer (BF), and the combination of SS and BF (SSBF) on rice grain yield, Cd, Pb, and Zn and nutrient accumulation in brown rice, bioavailability of Cd, Pb, and Zn in soil as well as soil properties (pH and catalase), at two acidic paddy fields contaminated with mixed heavy metals (Cd, Pb, and Zn). Compared to the controls, SS, LS, and SSBF at both low and high additions significantly elevated soil pH over both cultivation seasons. The high treatments of SS and SSBF markedly increased grain yields, the accumulation of P and Ca in brown rice and soil catalase activities in the first cultivation season. The most striking result was from SS application (4.0 t ha⁻¹) that consistently and significantly reduced the soil bioavailability of Cd, Pb, and Zn by 38.5–91.2 % and the concentrations of Cd and Pb in brown rice by 20.9–50.9 % in the two soils over both cultivation seasons. LS addition (4.0 t ha⁻¹) also markedly reduced the bioavailable Cd, Pb, and Zn in soil and the Cd concentrations in brown rice. BF remobilized soil Cd and Pb leading to more accumulation of these metals in brown rice. The results showed that steel slag was most effective in the remediation of acidic paddy soils contaminated with mixed heavy metals.
Mostrar más [+] Menos [-]PAMAM dendrimers as nano carriers to investigate inflammatory responses induced by pulmonary exposure of PCB metabolites in Sprague-Dawley rats Texto completo
2016
Wangpradit, Orarat | Adamcakova-Dodd, Andrea | Heitz, Katharina | Robertson, Larry | Thorne, Peter S. | Luthe, Gregor
Polychlorinated biphenyls (PCBs) persist and accumulate in the ecosystem depending upon the degree of chlorination of the biphenyl rings. Airborne PCBs are especially susceptible to oxidative metabolism, yielding mono- and di-hydroxy metabolites. We have previously demonstrated that 4-chlorobiphenyl hydroquinones (4-CB-HQs) acted as cosubstrates for arachidonic acid metabolism by prostaglandin H synthase (PGHS) and resulted in an increase of prostaglandin production in vitro. In the present study, we tested the capability of 4-CB-HQ to act as a co-substrate for PGHS catalysis in vivo. BQ and 4-CB-2′,5′-HQ were administered intratracheally to male Sprague-Dawley rats (2.5 μmol/kg body weight) using nanosized polyamidoamine (PAMAM) dendrimers as carriers. We found that 24 h post application, PGE₂ metabolites in kidney of rats treated with 4-CB-2′,5′-HQ were significantly increased compared to the controls. The increase of PGE₂ metabolites was correlated with increased alveolar macrophages in lung lavage fluid. The elevation of PGE₂ synthesis is of great interest since it plays a crucial role in balancing homeostasis and inflammation where a chronic disturbance may increase risk of cancer. PAMAM dentrimers proved to be an effective transport medium and did not stimulate an inflammatory response themselves.
Mostrar más [+] Menos [-]Calcium signaling and copper toxicity in Saccharomyces cerevisiae cells Texto completo
2016
Ruta, Lavinia L. | Popa, Claudia V. | Nicolau, Ioana | Farcasanu, Ileana C.
To respond to metal surpluses, cells have developed intricate ways of defense against the excessive metallic ions. To understand the ways in which cells sense the presence of toxic concentration in the environment, the role of Ca²⁺ in mediating the cell response to high Cu²⁺ was investigated in Saccharomyces cerevisiae cells. It was found that the cell exposure to high Cu²⁺ was accompanied by elevations in cytosolic Ca²⁺ with patterns that were influenced not only by Cu²⁺ concentration but also by the oxidative state of the cell. When Ca²⁺ channel deletion mutants were used, it was revealed that the main contributor to the cytosolic Ca²⁺ pool under Cu²⁺ stress was the vacuolar Ca²⁺ channel, Yvc1, also activated by the Cch1-mediated Ca²⁺ influx. Using yeast mutants defective in the Cu²⁺ transport across the plasma membrane, it was found that the Cu²⁺-dependent Ca²⁺ elevation could correlate not only with the accumulated metal, but also with the overall oxidative status. Moreover, it was revealed that Cu²⁺ and H₂O₂ acted in synergy to induce Ca²⁺-mediated responses to external stress.
Mostrar más [+] Menos [-]Assessment of toxic and endocrine potential of substances migrating from selected toys and baby products Texto completo
2016
Szczepańska, Natalia | Namieśnik, Jacek | Kudłak, Błażej
Analysis of literature data shows that there is limited information about the harmful biological effects of mixture of compounds from the EDC group that are released from the surface of toys and objects intended for children and infants. One of the tools that can be used to obtain such information is appropriate bioanalytical tests. The aim of this research involved determining whether tests that use living organisms as an active element (Vibrio fischeri—Microtox®, Heterocypris incongruens—Ostrocodtoxkit F™ and the XenoScreen YES/YAS™ test of oestrogenic/androgenic activity) can be a tool for estimating the combined toxic effects induced by xenobiotics released from objects intended for children. To reproduce the conditions to which objects are exposed during their use, liquids with a composition corresponding to that of human bodily fluids (artificial sweat and saliva) were used. This research focused on the main parameters influencing the intensification of the migration process (temperature, contact time and composition of the extraction mixture). The studies aimed to estimate the endocrine potential of the extracts showed that compounds released from the surface of studied objects exhibit antagonistic androgenic activity. While on the basis of the results of Microtox® test, one can state that the largest quantity of toxic compounds are released in the first 2 h of using the object. The FTIR spectra analyses confirmed that no degradation of polymeric material took place. On the basis of the results obtained, it was unanimously concluded that contact of the object with bodily fluids may result in the release of a large number of xenobiotics, which has disadvantageous effects on the metabolic processes of the indicator organisms.
Mostrar más [+] Menos [-]Modeling and kinetic characterization of wastewater disinfection using chlorine and UV irradiation Texto completo
2016
Mounaouer, Brahmi | Abdennaceur, Hassen
Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine alone, ultraviolet radiation alone, and a combined disinfection process (chlorine-UV radiation). Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 11229, Salmonella typhi ATCC 14028, and Clostridium perfringens were selected to evaluate the efficiency of different disinfection processes. The aim of the present study was to characterize the kinetics of chlorine (as NaHOCl) consumption, to evaluate responses of these bacterial species to the chlorination, the ultraviolet (UV) radiation, and the chlorine/UV disinfection processes in secondary wastewater using a batch laboratory reactor. Another target of this work was to study the modeling of the kinetic of water disinfection by chlorination and/or UV irradiation. Two kinetic models (Chick-Watson and Hom) were tested as to ability to scale disinfection of these bacterial species by different ultraviolet and/or chlorine doses. The results of the kinetics of chlorine consumption showed that monochloramines and trichloramines were the most important forms of residual chlorine as compared to free chlorine and dichloramines. The kinetics of inactivation of all examined bacterial strains showed that the application of the model of Hom in its original form was not representative of this kinetics of inactivation. Modification of this model, considering an initial decline of bacteria during the contact of water with chlorine, improved the results of the model. By the same, results revealed that the involved processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of microorganisms and the use of nearly constant UV radiation intensity. In fact, the results have pointed out that the application of the Chick-Watson law is known to be inadequate to describe microbial inactivation with tailing or shoulder behavior. However, the UV kinetic studies also revealed that the first instants of exposure (2 to 10 s) to a UV intensity of 5 to 8 mW.cm-2 appeared as the deciding factors in disinfection with UV irradiation. It was shown that the combination of chlorine with UV yielded additive effects on the inactivation of bacterial strains and spectacular disinfection efficiency at a short contact time and less dose. In contrast to most studies, UV irradiation alone and chlorine alone exhibited low disinfection efficiency in inactivation of tested bacterial strains.
Mostrar más [+] Menos [-]Thermal and spectral characterization of anaerobic thermal behavior patterns in a lacustrine sediment core Texto completo
2016
Guo, Fei | Mu, Yunsong | Chen, Cheng | Liao, Haiqing | Bai, Yingchen
The thermal evolution of sedimentary organic matter is a significant mechanism in continental oil and gas formation. This study presents a new method to estimate vertical thermal evolution trends in a lake sediment core. Twenty sediment samples from a 60-cm core recovered from Lake Bosten were heated to 600 °C at a rate of 10 °C min⁻¹ under a N₂ atmosphere. The sediments were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and then, the samples were analyzed with total organic carbon (TOC) analyses, X-ray diffraction, and ¹³⁷Cs isotopic dating techniques. Two main anaerobic thermal degradation processes were observed in the thermograms. The pyrolysis results showed variations with sediment age, with labile carbon (237.2 ± 42.98 °C) manifesting different thermogram patterns than recalcitrant carbon (498.35 ± 30.09 °C). There was a significant linear correlation between sample weight loss and TOC (r = 0.972, p < 0.001), as well as between the DSC and TGA peaks (r = 0.963, p < 0.001). As a conclusion, the thermal stability of both labile organic carbon and recalcitrant organic carbon in lacustrine sediment core increased gradually with age. These results confirm that advanced thermal techniques (DSC and TGA) operated in inert gas are potential quantitative methods to characterize the anaerobic thermal behavior of sediment organic carbon.
Mostrar más [+] Menos [-]Comparison greenhouse gas (GHG) emissions and global warming potential (GWP) effect of energy use in different wheat agroecosystems in Iran Texto completo
2016
Yousefi, Mohammad | Mahdavi Damghani, Abdolmajid | Khoramivafa, Mahmud
The aims of this study were to determine energy requirement and global warming potential (GWP) in low and high input wheat production systems in western of Iran. For this purpose, data were collected from 120 wheat farms applying questionnaires via face-to-face interviews. Results showed that total energy input and output were 60,000 and 180,000 MJ ha⁻¹ in high input systems and 14,000 and 56,000 MJ ha⁻¹ in low input wheat production systems, respectively. The highest share of total input energy in high input systems recorded for electricity power, N fertilizer, and diesel fuel with 36, 18, and 13 %, respectively, while the highest share of input energy in low input systems observed for N fertilizer, diesel fuel, and seed with 32, 31, and 27 %. Energy use efficiency in high input systems (3.03) was lower than of low input systems (3.94). Total CO₂, N₂O, and CH₄ emissions in high input systems were 1981.25, 31.18, and 1.87 kg ha⁻¹, respectively. These amounts were 699.88, 0.02, and 0.96 kg ha⁻¹ in low input systems. In high input wheat production systems, total GWP was 11686.63 kg CO₂eq ha⁻¹ wheat. This amount was 725.89 kg CO₂eq ha⁻¹ in low input systems. The results show that 1 ha of high input system will produce greenhouse effect 17 times of low input systems. So, high input production systems need to have an efficient and sustainable management for reducing environmental crises such as change climate.
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