خيارات البحث
النتائج 1431 - 1440 من 2,513
Human health risk from organ-specific accumulation of toxic metals and response of antioxidants in edible fish species from Chenab River, Pakistan النص الكامل
2014
Waheed, Sidra | Kamal, Atif | Malik, Riffat Naseem
In the current study, the bioaccumulation of essential and nonessential metals and related antioxidant activity were analyzed in three organs (muscle, gills, and liver) of herbivorous (HF) and carnivorous (CF) edible fish of Chenab River. The comparative analysis revealed a more heterogeneous accumulation of metals in the muscles of HF fish than that of CF fish [chromium (Cr, 3.4 μg g⁻¹), cobalt (Co, 1.7 μg g⁻¹), copper (Cu, 3 μg g⁻¹), and iron (Fe, 45 μg g⁻¹) versus Cr (1.3 μg g⁻¹), Co (0.1 μg g⁻¹), Cu (1.1 μg g⁻¹), and Fe (33 μg g⁻¹), respectively, P < 0.001]. These results implied an organ-specific accumulation of metals at different trophic levels. According to logistic regression analysis, the bioaccumulation of metals had marked differences in HF and CF. The antioxidant activity was significantly related to the tissue type and the metals to which the organs are exposed to. The liver of CF fish had a higher activity of antioxidant superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and lipid peroxidase (LPO) than that of HF (P < 0.05). LPO and guaiacol peroxidase (POD) in both groups were associated with a number of metals, but in HF, cadmium (Cd), Cr, Pb, and Zn were more related with the LPO and SOD activities. Moreover, Cd, Co, Fe, Pb, Ni, Cu, and Zn were above the permissible limits set by various agencies. In numerous cases, our results were even higher than those previously reported in the literature. The results provide an insight into the pollution pattern of Chenab River. These results may be helpful in the future to identify biomarkers of exposure in aquatic organisms.
اظهر المزيد [+] اقل [-]Development and implementation of surface water quality standards for protection of human health in Korea النص الكامل
2014
An, Youn-Joo | Kwak, Jin II | Nam, Sun-Hwa | Jung, Myung-sook
Current water quality standards for the protection of human health in Korea include 17 substances found in rivers and streams. Due to increasing concern over the release of hazardous chemicals into the aquatic environment, there has been a demand for additional water quality standards. Therefore, the Korean Ministry of the Environment plans to gradually increase the number of water quality standards to 30 substances, including 22 substances for protection of human health and 8 substances for protection of aquatic ecosystems by 2015. In this study, new water quality standards for protection of human health were established for 1,4-dioxane, formaldehyde, and hexachlorobenzene. We selected candidate hazardous chemicals, conducted a human health risk assessment to determine priority chemicals, established water quality standards based on technical analyses and comparison with domestic and developed countries’ water quality standards, and conducted an expert review. Water quality standards for protection of aquatic ecosystems will be derived in the near future. This study describes how the water quality standards for protection of human health were developed and implemented. Current status, recent expansion, and future plans for water quality standards in Korea are also covered.
اظهر المزيد [+] اقل [-]Characteristics of water-soluble inorganic ions in PM2.5 and PM 2.5–10 in the coastal urban agglomeration along the Western Taiwan Strait Region, China النص الكامل
2014
Yin, Liqian | Niu, Zhenchuan | Chen, Xiaoqiu | Chen, Jinsheng | Zhang, Fuwang | Xu, Lingling
PM₂.₅and PM₂.₅–₁₀aerosol samples were collected in four seasons during November 2010, January, April, and August 2011 at 13 urban/suburban sites and one background site in Western Taiwan Straits Region (WTSR), which is the coastal area with rapid urbanization, high population density, and deteriorating air quality. The 10 days average PM₂.₅concentrations were 92.92, 51.96, 74.48, and 89.69 μg/m³in spring, summer, autumn, and winter, respectively, exceeding the Chinese ambient air quality standard for annual average value of PM₂.₅(grade II, 35 μg/m³). Temporal distribution of water-soluble inorganic ions (WSIIs) in PM₂.₅was coincident with PM₂.₅mass concentrations, showing highest in spring, lowest in summer, and middle in autumn and winter. WSIIs took considerable proportion (42.2∼50.1 %) in PM₂.₅and PM₂.₅–₁₀. Generally, urban/suburban sites had obviously suffered severer pollution of fine particles compared with the background site. The WSIIs concentrations and characteristics were closely related to the local anthropogenic activities and natural environment, urban sites in cities with higher urbanization level, or sites with weaker diffuse condition suffered severer WSIIs pollution. Fossil fuel combustion, traffic emissions, crustal/soil dust, municipal constructions, and sea salt and biomass burnings were the major potential sources of WSIIs in PM₂.₅in WTSR according to the result of principal component analysis.
اظهر المزيد [+] اقل [-]Survival of Escherichia coli O157:H7 in soils under different land use types النص الكامل
2014
Wang, Haizhen | Zhang, Taoxiang | Wei, Gang | Wu, Laosheng | Wu, Jianjun | Xu, Jianming
Laboratory studies on Escherichia coli O157:H7 survival in soils from four different land use types: forest, tea plantation, bamboo grove, and vegetable garden were investigated at 25 ± 1 °C with the field capacity (soil water content at −33 kPa). Results showed that E. coli O157:H7 declined quickly in the test soils, but its survival dynamics varied in the soils under different land use types. The survival time needed to reach the detection limit (td) in the test soils ranged from 2.1 to 3.6 days, with slightly longer tdvalues being observed in soils from the bamboo grove. Stepwise multiple regression analysis revealed that the tdvalues were shorter in sandy, lower pH, and lower organic carbon content soils. Different E. coli O157:H7 survival time in the soils under different land uses suggests that it is important to adapt proper management practices for reducing the potential risks of pathogen contamination when diary manure is applied to agricultural land.
اظهر المزيد [+] اقل [-]Contrasting cellular stress responses of Baikalian and Palearctic amphipods upon exposure to humic substances: environmental implications النص الكامل
2014
Protopopova, Marina V. | Pavlichenko, Vasiliy V. | Menzel, Ralph | Putschew, Anke | Luckenbach, Till | Steinberg, Christian E. W.
The species-rich, endemic amphipod fauna of Lake Baikal does not overlap with the common Palearctic fauna; however, the underlying mechanisms for this are poorly understood. Considering that Palearctic lakes have a higher relative input of natural organic compounds with a dominance of humic substances (HSs) than Lake Baikal, we addressed the question whether HSs are candidate factors that affect the different species compositions in these water bodies. We hypothesized that interspecies differences in stress defense might reveal that Baikalian amphipods are inferior to Palearctic amphipods in dealing with HS-mediated stress. In this study, two key mechanisms of general stress response were examined: heat-shock protein 70 (HSP70) and multixenobiotic resistance-associated transporters (ABCB1). The results of quantitative polymerase chain reaction (qPCR) showed that the basal levels (in 3-day acclimated animals) of hsp70 and abcb1 transcripts were lower in Baikalian species (Eulimnogammarus cyaneus, Eulimnogammarus verrucosus, Eulimnogammarus vittatus—the most typical littoral species) than in the Palearctic amphipod (Gammarus lacustris—the only Palearctic species distributed in the Baikalian region). In the amphipods, the stress response was induced using HSs at 10 mg L⁻¹dissolved organic carbon, which was higher than in sampling sites of the studied species, but well within the range (3–10 mg L⁻¹) in the surrounding water bodies populated by G. lacustris. The results of qPCR and western blotting (n = 5) showed that HS exposure led to increased hsp70/abcb1 transcripts and HSP70 protein levels in G. lacustris, whereas these transcript levels remained constant or decreased in the Baikalian species. The decreased level of stress transcripts is probably not able to confer an effective tolerance to Baikalian species against further environmental stressors in conditions with elevated HS levels. Thus, our results suggest a greater robustness of Palearctic amphipods and a higher sensitivity of Baikalian amphipods to HS challenge, which might prevent most endemic species from migrating to habitats outside Lake Baikal.
اظهر المزيد [+] اقل [-]Chemically coupled microwave and ultrasonic pre-hydrolysis of pulp and paper mill waste-activated sludge: effect on sludge solubilisation and anaerobic digestion النص الكامل
2014
Tyagi, Vinay Kumar | Lo, Shang-Lien | Rajpal, Ankur
The effects of alkali-enhanced microwave (MW; 50–175 °C) and ultrasonic (US) (0.75 W/mL, 15–60 min) pretreatments, on solubilisation and subsequent anaerobic digestion efficiency of pulp and paper mill waste-activated sludge, were investigated. Improvements in total chemical oxygen demand and volatile suspended solids (VSS) solubilisation were limited to 33 and 39 % in MW pretreatment only (175 °C). It reached 78 and 66 % in combined MW–alkali pretreatment (pH 12 + 175 °C), respectively. Similarly, chemical oxygen demand and VSS solubilisation were 58 and 37 % in US pretreatment alone (60 min) and it improved by 66 and 49 % after US–alkali pretreatment (pH 12 + 60 min), respectively. The biogas yield for US 60 min–alkali (pH 12)-pretreated sludge was significantly improved by 47 and 20 % over the control and US 60 reactors, respectively. The biogas generation for MW (150 °C)–alkali (pH 12)-pretreated sludge was only 6.3 % higher than control; however, it was 8.3 % lower than the MW (150 °C) reactor, which was due to the inhibition of anaerobic activity under harsh thermal–alkali treatment condition.
اظهر المزيد [+] اقل [-]The GMOS cyber(e)-infrastructure: advanced services for supporting science and policy النص الكامل
2014
Cinnirella, S. | D’Amore, F. | Bencardino, M. | Sprovieri, F. | Pirrone, N.
The need for coordinated, systematized and catalogued databases on mercury in the environment is of paramount importance as improved information can help the assessment of the effectiveness of measures established to phase out and ban mercury. Long-term monitoring sites have been established in a number of regions and countries for the measurement of mercury in ambient air and wet deposition. Long term measurements of mercury concentration in biota also produced a huge amount of information, but such initiatives are far from being within a global, systematic and interoperable approach. To address these weaknesses the on-going Global Mercury Observation System (GMOS) project ( www.gmos.eu ) established a coordinated global observation system for mercury as well it retrieved historical data ( www.gmos.eu/sdi ). To manage such large amount of information a technological infrastructure was planned. This high-performance back-end resource associated with sophisticated client applications enables data storage, computing services, telecommunications networks and all services necessary to support the activity. This paper reports the architecture definition of the GMOS Cyber(e)-Infrastructure and the services developed to support science and policy, including the United Nation Environmental Program. It finally describes new possibilities in data analysis and data management through client applications.
اظهر المزيد [+] اقل [-]Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays النص الكامل
2014
Wang, Jingxian | Bovee, Toine F. H. | Bi, Yonghong | Bernhöft, Silke | Schramm, Karl-Werner
Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated activities. The estrogenic activity was assessed using a rapid yeast estrogen bioassay, based on the expression of a green fluorescent reporter protein. Weak anti-estrogenic activity was detected in sediments from an area close to the dam of the reservoir, and weak estrogenic activities ranging from 0.3 to 1 ng 17β-estradiol (E2) equivalents (EQ) g⁻¹dry weight sediment (dw) were detected in sediments from the Wanzhou to Guojiaba areas. In the upstream areas Wanzhou and Wushan, sediments demonstrated additive effects in co-administration of 1 nM E2 in the yeast test system, while sediments from the downstream Badong and Guojiaba areas showed estrogenic activities which seemed to be more than additive (synergistic activity). There was an increasing tendency in estrogenic activity from upstream of TGR to downstream, while this tendency terminated and converted into anti-estrogenic activity in the area close to the dam. The AhR activity was detected employing rat hepatoma cell line (H4IIE). EROD activities were found homogenously distributed in sediments in TGR ranging from 200 to 311 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) EQ g⁻¹dw for total AhR agonists and from 45 to 76 pg TCDD EQ g⁻¹dw for more persistent AhR agonists. The known AhR agonists polycyclic aromatic hydrocarbon, polychlorinated biphenyl, and PCDD/F only explained up to 8 % of the more persistent AhR agonist activity in the samples, which suggests that unidentified AhR-active compounds represented a great proportion of the TCDD EQ in sediments from TGR. These findings of estrogenic potential and dioxin-like activity in TGR sediments provide possible weight-of-evidence of potential ecotoxicological causes for the declines in fish populations which have been observed during the past decades in TGR.
اظهر المزيد [+] اقل [-]Effects of climate change on surface-water photochemistry: a review النص الكامل
2014
De Laurentiis, Elisa | Minella, Marco | Maurino, Valter | Minero, Claudio | Vione, Davide
Information concerning the link between surface-water photochemistry and climate is presently very scarce as only a few studies have been dedicated to the subject. On the basis of the limited knowledge that is currently available, the present inferences can be made as follows: (1) Warming can cause enhanced leaching of ionic solutes from the catchments to surface waters, including cations and more biologically labile anions such as sulphate. Preferential sulphate biodegradation followed by removal as organic sulphides in sediment could increase alkalinity, favouring the generation of the carbonate radical, CO₃ ·⁻. However, this phenomenon would be easily offset by fluctuations of the dissolved organic carbon (DOC), which is strongly anticorrelated with CO₃ ·⁻. Therefore, obtaining insight into DOC evolution is a key issue in understanding the link between photochemistry and climate. (2) Climate change could exacerbate water scarcity in the dry season in some regions. Fluctuations in the water column could deeply alter photochemistry that is usually favoured in shallower waters. However, the way water is lost would strongly affect the prevailing photoinduced processes. Water outflow without important changes in solute concentration would mostly favour reactions induced by the hydroxyl and carbonate radicals (·OH and CO₃ ·⁻). In contrast, evaporative concentration would enhance reactions mediated by singlet oxygen (¹O₂) and by the triplet states of chromophoric dissolved organic matter (³CDOM*). (3) In a warmer climate, the summer stratification period of lakes would last longer, thereby enhancing photochemical reactions in the epilimnion but at the same time keeping the hypolimnion water in the dark for longer periods.
اظهر المزيد [+] اقل [-]Comparisons of operating envelopes for contaminated soil stabilised/solidified with different cementitious binders النص الكامل
2014
Kogbara, Reginald B. | Al-Tabbaa, Abir | Stegemann, Julia A.
This work initiated the development of operating envelopes for stabilised/solidified contaminated soils. The operating envelopes define the range of operating variables for acceptable performance of the treated soils. The study employed a soil spiked with 3,000 mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000 mg/kg of diesel. The binders used for treatment involved Portland cement (CEMI), pulverised fuel ash (PFA), ground granulated blast furnace slag (GGBS) and hydrated lime (hlime). The specific binder formulations were CEMI, CEMI/PFA = 1:4, CEMI/GGBS = 1:9 and hlime/GGBS = 1:4. The water contents employed ranged from 13 % to 21 % (dry weight), while binder dosages ranged from 5 % to 20 % (w/w). We monitored the stabilised/solidified soils for up to 84 days using different performance tests. The tests include unconfined compressive strength (UCS), hydraulic conductivity, acid neutralisation capacity (ANC) and pH-dependent leachability of contaminants. The water content range resulted in adequate workability of the mixes but had no significant effect on leachability of contaminants. We produced design charts, representing operating envelopes, from the results generated. The charts establish relationships between water content, binder dosage and UCS; and binder dosage, leachant pH and leachability of contaminants. The work also highlights the strengths and weaknesses of the different binder formulations.
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