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Результаты 41-50 из 2,512
Predicting criteria continuous concentrations of 34 metals or metalloids by use of quantitative ion character-activity relationships–species sensitivity distributions (QICAR–SSD) model Полный текст
2014
Mu, Yunsong | Wu, Fengchang | Chen, Cheng | Liu, Yuedan | Zhao, Xiaoli | Haiqing Liao, | Giesy, John P.
Criteria continuous concentrations (CCCs) are useful for describing chronic exposure to pollutants and setting water quality standards to protect aquatic life. However, because of financial, practical, or ethical restrictions on toxicity testing, few data are available to derive CCCs. In this study, CCCs for 34 metals or metalloids were derived using quantitative ion character-activity relationships–species sensitivity distributions (QICAR–SSD) and the final acute-chronic ratio (FACR) method. The results showed that chronic toxic potencies were correlated with several physico-chemical properties among eight species chosen, where the softness index was the most predictive characteristic. Predicted CCCs for most of the metals, except for Lead and Iron, were within a range of 10-fold of values recommended by the U.S. EPA. The QICAR–SSD model was superior to the FACR method for prediction of data-poor metals. This would have significance for predicting toxic potencies and criteria thresholds of more metals or metalloids.
Показать больше [+] Меньше [-]Fate of copper complexes in hydrothermally altered deep-sea sediments from the Central Indian Ocean Basin Полный текст
2014
Chakraborty, Parthasarathi | Sander, Sylvia G. | Jayachandran, Saranya | Nath, B Nagender | Nagaraju, G. | Chennuri, Kartheek | Vudamala, Krushna | Lathika, N. | Mascarenhas-Pereira, Maria Brenda L.
The current study aims to understand the speciation and fate of Cu complexes in hydrothermally altered sediments from the Central Indian Ocean Basin and assess the probable impacts of deep-sea mining on speciation of Cu complexes and assess the Cu flux from this sediment to the water column in this area. This study suggests that most of the Cu was strongly associated with different binding sites in Fe-oxide phases of the hydrothermally altered sediments with stabilities higher than that of Cu-EDTA complexes. The speciation of Cu indicates that hydrothermally influenced deep-sea sediments from Central Indian Ocean Basin may not significantly contribute to the global Cu flux. However, increasing lability of Cu-sediment complexes with increasing depth of sediment may increase bioavailability and Cu flux to the global ocean during deep-sea mining.
Показать больше [+] Меньше [-]Sorption of phenanthrene and benzene on differently structural kerogen: Important role of micropore-filling Полный текст
2014
Zhang, Yulong | Ma, Xiaoxuan | Ran, Yong
Shale was thermally treated to obtain a series of kerogen with varied maturation. Their chemical, structural and porous properties were related to the sorption and/or desorption behaviors of phenanthrene and benzene. As the treatment temperature increases, aliphatic and carbonyl carbon of the kerogen samples decrease, while their aromaticity and maturation increase. Meanwhile, the isothermal nonlinearity of phenanthrene and benzene increases whereas the sorption capacity and micropore adsorption volumes (Vo,d) initially increase and then decrease. The Vo,d of benzene is significantly correlated with, but higher than that of phenanthrene, suggesting similar micropore filling mechanism and molecular sieve effect. The benzene desorption exhibits hysteresis, which is related to the pore deformation of the kerogen and the entrapment of solute in the kerogen matrix. The Vo,d of phenanthrene and benzene on the kerogen samples accounts for 23–46% and 36–65% of the maximum sorption volumes, respectively, displaying the importance of the micropore filling.
Показать больше [+] Меньше [-]Use, fate and ecological risks of antibiotics applied in tilapia cage farming in Thailand Полный текст
2014
Rico, Andreu | Oliveira, Rhaul | McDonough, Sakchai | Matser, Arrienne | Khatikarn, Jidapa | Satapornvanit, Kriengkrai | Nogueira, António J.A. | Soares, Amadeu M.V.M. | Domingues, Inês | Van den Brink, Paul J.
Use, fate and ecological risks of antibiotics applied in tilapia cage farming in Thailand Полный текст
2014
Rico, Andreu | Oliveira, Rhaul | McDonough, Sakchai | Matser, Arrienne | Khatikarn, Jidapa | Satapornvanit, Kriengkrai | Nogueira, António J.A. | Soares, Amadeu M.V.M. | Domingues, Inês | Van den Brink, Paul J.
The use, environmental fate and ecological risks of antibiotics applied in tilapia cage farming were investigated in the Tha Chin and Mun rivers in Thailand. Information on antibiotic use was collected through interviewing 29 farmers, and the concentrations of the most commonly used antibiotics, oxytetracycline (OTC) and enrofloxacin (ENR), were monitored in river water and sediment samples. Moreover, we assessed the toxicity of OTC and ENR on tropical freshwater invertebrates and performed a risk assessment for aquatic ecosystems. All interviewed tilapia farmers reported to routinely use antibiotics. Peak water concentrations for OTC and ENR were 49 and 1.6 μg/L, respectively. Antibiotics were most frequently detected in sediments with concentrations up to 6908 μg/kg d.w. for OTC, and 2339 μg/kg d.w. for ENR. The results of this study indicate insignificant short-term risks for primary producers and invertebrates, but suggest that the studied aquaculture farms constitute an important source of antibiotic pollution.
Показать больше [+] Меньше [-]Use, fate and ecological risks of antibiotics applied in tilapia cage farming in Thailand Полный текст
1000 | 2014
Rico, Andreu | Oliveira, Rhaul | McDonough, Sakchai | Matser, Arrienne | Khatikarn, Jidapa | Satapornvanit, Kriengkrai | Nogueira, António J. A. | Soares, Amadeu M. V. M. | Domingues, Inês | Van Den Brink, Paul J.
The use, environmental fate and ecological risks of antibiotics applied in tilapia cage farming were investigated in the Tha Chin and Mun rivers in Thailand. Information on antibiotic use was collected through interviewing 29 farmers, and the concentrations of the most commonly used antibiotics, oxytetracycline (OTC) and enrofloxacin (ENR), were monitored in river water and sediment samples. Moreover, we assessed the toxicity of OTC and ENR on tropical freshwater invertebrates and performed a risk assessment for aquatic ecosystems. All interviewed tilapia farmers reported to routinely use antibiotics. Peak water concentrations for OTC and ENR were 49 and 1.6 μg/L, respectively. Antibiotics were most frequently detected in sediments with concentrations up to 6908 μg/kg d.w. for OTC, and 2339 μg/kg d.w. for ENR. The results of this study indicate insignificant short-term risks for primary producers and invertebrates, but suggest that the studied aquaculture farms constitute an important source of antibiotic pollution.
Показать больше [+] Меньше [-]Characteristics and cellular effects of ambient particulate matter from Beijing Полный текст
2014
Lu, Yan | Su, Shu | Jin, Wenjie | Wang, Bin | Li, Ning | Shen, Huizhong | Li, Wei | Huang, Ye | Chen, Han | Zhang, Yanyan | Chen, Yuanchen | Lin, Nan | Wang, Xilong | Tao, Shu
In vitro tests using human adenocarcinomic alveolar epithelial cell line A549 and small mouse monocyte-macrophage cell line J774A.1 were conducted to test toxicity of six PM (particulate matter) samples from Beijing. The properties of the samples differ significantly. The production of inflammatory cytokine (TNF-α for J774A.1) and chemokine (IL-8 for A549) and the level of intracellular reactive oxygen species (ROS) were used as endpoints. There was a positive correlation between water soluble organic carbon and DTT-based redox activity. Both cell types produced increased levels of inflammatory mediators and had higher level of intracelllar ROS, indicating the presence of PM-induced inflammatory response and oxidative stress, which were dose-dependent and significantly different among the samples. The releases of IL-8 from A549 and TNF-α from J774A.1 were significantly correlated to PM size, Zeta potential, endotoxin, major metals, and polycyclic aromatic hydrocarbons. No correlation between ROS and these properties was identified.
Показать больше [+] Меньше [-]Soil physical characteristics after EDTA washing and amendment with inorganic and organic additives Полный текст
2014
Zupanc, Vesna | Kastelec, Damijana | Lestan, Domen | Grcman, Helena
Soil washing has been established as suitable remediation technology, with most research focused on metal removing efficiency and toxic effect on plants, less on the influence on soil physical characteristics, which was the focus of this study. In soil column experiment highly contaminated soil and soil washed with EDTA, mixed with additives (gypsum, hydrogel, manure, peat) were tested. White clover was used as a soil cover. Yield, metal concentration in soil and plant, aggregate fractionation and stability, saturated hydraulic conductivity and soil water retention of the soil were measured. Soil washing decreased metal concentration in soil and plants, but yield of white clover on remediated soil was significantly lower compared to the original soil. Significant differences in water retention characteristics, aggregate fractionation and stability between original and remediated soil have been determined. Gypsum, hydrogel and peat increased plant available water, manure and peat increased yield on remediated soil.
Показать больше [+] Меньше [-]Mechanism of and relation between the sorption and desorption of nonylphenol on black carbon-inclusive sediment Полный текст
2014
Liping, Lou | Guanghuan, Cheng | Jingyou, Deng | Mingyang, Sun | Huanyu, Chen | Qiang, Yang | Xinhua, Xu
Correlation between the sorption and desorption of nonylphenol (NP) and binary linear regression were conducted to reveal the underlying mechanism of and relation between sorption domains and desorption sites in black carbon (BC)-amended sediment. The sorption and desorption data could be fitted well using dual-mode (R2 = 0.971–0.996) and modified two-domain model (R2 = 0.986–0.995), respectively, and there were good correlations between these two parts of parameters (R2 = 0.884–0.939, P < 0.01). The NP percentage in desorbable fraction was almost equal to that of the partition fraction, suggesting the desorbed NP came from linear partition domain, whereas the resistant desorption NP was segregated in nonlinear adsorption sites, which were dominated by pores in BC-amended sediment. Our investigation refined theory about the relation between sorption domains and desorption sites in sediment and could be used to predict the release risk of NP using sorption data when BC is used for NP pollution control.
Показать больше [+] Меньше [-]Dose-response relationship between polycyclic aromatic hydrocarbon metabolites and risk of diabetes in the general Chinese population Полный текст
2014
Yang, Liangle | Zhou, Yun | Sun, Huizhen | Lai, Hanpeng | Liu, Chuanyao | Yan, Kai | Yuan, Jing | Wu, Tangchun | Chen, Weihong | Zhang, Xiaomin
The incidence of diabetes is increasing rapidly in Chinese population, and it has been postulated that environmental factors may play a role in the etiology of diabetes. Therefore, we aimed to investigate the association between PAHs exposure and risk of diabetes in a community-based population of 2824 participants with completed questionnaires, measurements of biochemical indices, and urinary PAHs metabolites. We found that elevated urinary PAHs metabolites were associated, in a dose-dependent manner, with increased risk of diabetes. Particularly, these associations were more evident in subjects who were female, less than 55 years old, nonsmokers, and normal weight. In addition, there was a modest improvement in diabetes discrimination of prediction models when incorporating certain PAHs metabolites into conventional risk factors (CRF). Overall, our data suggested that there may be a dose-dependent relationship between PAHs metabolites and risk of diabetes among general Chinese population.
Показать больше [+] Меньше [-]Homologue specific analysis of a polyether trisiloxane surfactant in German surface waters and study on its hydrolysis Полный текст
2014
The occurrence of a polyether trisiloxane surfactant in the ng L−1 range in German surface waters is reported for the first time. The studied surfactant does not ubiquitously occur in the aquatic environment but can reach surface waters on a local scale. As a first step towards the understanding of the environmental fate, the hydrolysis was studied according to the OECD guideline 111. It confirmed that the trisiloxane surfactant is sensitive to hydrolysis and that the hydrolysis rate strongly depends on the pH and the temperature. If one takes only into account the hydrolysis, the trisiloxane surfactant could persist several weeks in river water (the half-life in water is approximately 50 days at pH 7, 25 °C, and an initial concentration of 2 mg L−1). A degradation product, more polar than the initial trisiloxane surfactant, was identified by high resolution mass spectrometry.
Показать больше [+] Меньше [-]Development of a passive sampler for Zinc(II) in urban pond waters using a polymer inclusion membrane Полный текст
2014
Almeida, M. Inês G.S. | Chan, Cleopas | Pettigrove, Vincent J. | Cattrall, Robert W. | Kolev, Spas D.
The use of a polymer inclusion membrane (PIM) in a novel passive sampler to measure the time-weighted average concentration of Zn(II) in urban waters is described. The passive sampler consists of a compartment containing an acidic receiving solution, which is separated from the external source solution by a PIM consisting of 40 wt% di-2-(ethylhexyl) phosphoric acid as the extractant, and 60 wt% poly-(vinyl chloride) as the base polymer. Two laboratory passive sampling techniques were tested. One involved immersion of the passive sampler into a source solution (“dip-in” approach) for a predetermined period of time while in the other one the source solution was flown past the membrane of the sampler (“flow-through” approach). The latter approach was found to be more suitable for the calibration of the passive sampler under laboratory conditions. A successful application using the “dip-in” sampling approach in urban waters has been conducted for proof of concept.
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