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Результаты 1481-1490 из 4,309
Heavy metal concentrations in some gastropods and bivalves collected from the fishing zone of South India Полный текст
2017
Ragi, A.S. | Leena, P.P. | Cheriyan, Eldhose | Nair, S.M.
The present study investigates heavy metal concentrations in gastropods and bivalves collected from major fishing centers in South India. Three gastropods, Bursa spinosa, Tibia curta, and Murex trapa, and two bivalves, Perna viridis and Villoritta cyprinoids, were collected for the analysis of heavy metals. The metals in the present study followed the order Mg>Ca>Zn>Fe>Cu>Mn>Cr>Pb>Ni>Co>Cd. Trace metal concentrations in the soft tissue of the molluscs varied as follows: for Cd: 0.04–5.33, Co: 0.09–0.87, Cr: 2.18–7.59, Cu: 9.54–37.02, Mn: 1.30–8.50, Ni: 0.94–3.21, Pb: 1.16–2.64 and Zn: 68.16–113.64mgkg−1. Metal concentrations in all the species were below the limits proposed by the World Health Organization, except for Pb and Cd. This baseline study suggests that the levels of toxic metals in M. trapa, T. curta, and B. spinosa should be continuously monitored to assess the fate and effects of these metals in this fragile ecosystem.
Показать больше [+] Меньше [-]Determination and speciation of cadmium in microcosms with Bunodosoma caissarum and Perna perna using isotopically enriched 116Cd Полный текст
2017
Rizzini Ansari, Nafisa | Fernández Iglesias, Nerea | Cordeiro, Renato Campello | Fernandez, Marcos Antônio | Bettmer, Jörg
The study of the uptake and distribution of elements in marine environments is of great interest for understanding their pathways and accumulation. Here, we investigated in laboratory experiments the accumulation behavior of Cd in the sea anemone Bunodosoma caissarum and the mussel Perna perna. Specimens were incubated with isotopically enriched 116Cd in aquariums. Cd concentrations in the seawater and in the tissues of B. caissarum and P. perna were followed by inductively coupled plasma-mass spectrometry (ICP-MS) by means of isotope dilution analysis. Bioconcentration factors for B. caissarum and P. perna exposed to 0.9μg·L−1 of 116Cd were determined to be 80.5 and 850, respectively. P. perna specimens exposed to 4.5μg·L−1 of 116Cd reached 530. Cytosolic proteins associated with Cd from the tissues were extracted and further analyzed by size-exclusion chromatography coupled to ICP-MS. Cd accumulation could be detected in both organisms ranging from high-molecular to low-molecular species.
Показать больше [+] Меньше [-]Immunotoxic effects of single and combined pharmaceuticals exposure on a harbor seal (Phoca vitulina) B lymphoma cell line Полный текст
2017
Kleinert, Christine | Lacaze, Emilie | Mounier, Méryl | De Guise, Sylvain | Fournier, Michel
The potential risk of pharmaceuticals in the environment to top-predators is still largely unknown. In this study, we assessed the immunotoxic effects of ten pharmaceuticals individually and as mixtures on a harbor seal (Phoca vitulina) B lymphoma cell line. A significant reduction in lymphocyte transformation was observed following an exposure to 12,500μg/L 17α-ethinyl estradiol and 25,000μg/L naproxen. Exposure to 12,500μg/L 17α-ethinyl estradiol decreased the percentage of cell in the G0/G1 phase of the cell cycle while increasing the percentage of cells in the S phase. Carbamazepine exposure increased the amount of cells in the G2/M phase. Binary mixtures showed synergistic effects in lymphocyte transformation, cell cycle and apoptosis assays. Concentrations inducing toxic effects in the cell line were similar to those affecting fish in previous studies. A reduction of functional activities of the immune system may lead to altered host resistance to pathogens in free-ranging pinnipeds.
Показать больше [+] Меньше [-]Marine environment status assessment based on macrophytobenthic plants as bio-indicators of heavy metals pollution Полный текст
2017
Zalewska, Tamara | Danowska, Beata
The main aim of study was to develop the environmental quality standards (EQSMP) for selected heavy metals: Pb, Cd, Hg and Ni bioaccumulated in the tissues of marine macrophytobenthic plants: Chara baltica, Cladophora spp., Coccotylus truncatus, Furcellaria lumbricalis, Polysiphonia fucoides, Stuckenia pectinata and Zanichellia palustris, collected in designated areas of the southern Baltic Sea in period 2008–2015. The calculated concentration ratios (CR), which attained very high values: 104Lkg−1 for lead, 103Lkg−1 for nickel and mercury and even 105Lkg−1 for cadmium formed the basis for the determination of EQSMP values. The EQSMP values were: 26mgkg−1d.w. for Pb, 33mgkg−1d.w. for Cd, 32mgkg−1d.w. for Ni and 0.4mgkg−1d.w. for Hg. The application of macrophytobenthic plants as bioindicators in marine environment status assessment of certain areas of the Baltic Sea is also described in the paper.
Показать больше [+] Меньше [-]Daily relative dog abundance, fecal density, and loading rates on intensively and minimally managed dog-friendly beaches in central California Полный текст
2017
Oates, Stori C. | Miller, Melissa A. | Hardin, Dane | Dominik, Clare | Jessup, David | Smith, Woutrina A.
Due to increased concerns regarding fecal pollution at marine recreational beaches, daily relative dog abundance and fecal density were estimated on an intensively managed (Beach 1) and a minimally managed (Beach 2) dog beach in Monterey County, California. Fecal loading and factors predictive of fecal deposition also were assessed. After standardizing for beach area, daily beach use and fecal densities did not differ between beaches and yearly fecal loading estimates revealed that unrecovered dog feces likely contributes significantly to fecal contamination (1.4 and 0.2metrictonnes/beach). Detection of feces was significantly associated with beach management type, transect position relative to mean low tideline, presence of beach wrack, distance to the nearest beach entrance, and season. Methodologies outlined in this study can augment monitoring programs at coastal beaches to optimize management, assess visitor compliance, and improve coastal water quality.
Показать больше [+] Меньше [-]Assessing environmental health using ecological indices for soft bottom in sewage-affected rocky shores: The case of the largest seaside resort of SW Atlantic Полный текст
2017
Garaffo, GV | Jaubet, ML | Becherucci, ME | Elías, R
Efficient ecological indices can reflect the differences between impacted and nonimpacted sites, leading to significant variations at the contamination spatial scale. Here, we evaluated the spatial-temporal variability of 3 ecological indices (AMBI, M-AMBI, and BENTIX) in response to the distinct levels of sewage contamination. The indices were evaluated in two different ways: including Brachidontes rodriguezii (IBR) and excluding B. rodriguezii (EBR). The fact that mussel beds create a secondary infaunal habitat allows us to test these indices for soft bottoms in areas with rocky bottoms. The effectiveness and the level of agreement of these indices were increased when they were calculated with EBR. BENTIX and M-AMBI produced under- and overestimations of the ecological status of the studied sites. AMBI (EBR) seems to be better suited for environmental quality assessment in the study area. This index reduces the processing time of samples; thus, the AMBI (EBR) index could be used as a robust management tool for monitoring programs in areas with hard substrate.
Показать больше [+] Меньше [-]Oil permeability variations on lagoon sand beaches in the Patos-Guaíba system in Rio Grande do Sul, Brazil Полный текст
2017
Oliveira, Elaine Baroni | Nicolodi, João Luiz
Permeability is the ability of a sediment deposit to allow fluids to pass through it. It depends on the local types of sediments. When the fluid is oil, high permeability implies greater interaction with the site and more extensive damage, which makes recovery most difficult. Knowledge of permeability oscillations is necessary to understand oil behavior and improve cleanup techniques. The goal is to determine oil permeability variations on lagoon sand beaches. Oil permeability tests were performed at the beach face, using a Modified Phillip Dunne Permeameter and parameters were sampled. Permeability of lagoon beaches is driven by grain diameter and roundness, soil compaction, and depth of the water table. Factors that enhance permeability include: sand sorting, vertical distribution of sediments and gravel percentage. High permeability on lagoon beaches is related to polymodal distribution, to the sediment package, and to the system's low mobility.
Показать больше [+] Меньше [-]A model for the weathering of Colombian crude oils in the Colombian Caribbean Sea Полный текст
2017
Ramírez, Juan | Merlano, Aura | Lacayo, Juan | Osorio, Andres F. | Molina, Alejandro
A model that describes the weathering of crude in an oil spill caused by interaction with the atmosphere and the ocean was developed. This model was adapted to the Colombian crudes Cusiana (°API43.2) and Vasconia (°API20.7). To calibrate the model, evaporation and emulsification experiments were carried out at conditions similar to those of an oil spill in the Colombian Caribbean Sea. The dependence of evaporation with wind velocity, not predicted by the state-of-the-art models, was captured by a correlation for the mass transfer coefficient calculated from the experimental data. Emulsification rate, maximum water content and required evaporation to form an emulsion were determined and their values explained considering the effect of wax precipitation for Cusiana crude oil. When compared to well-established weathering software, such as ADIOS, the proposed model predicts the weathering of Colombian oils in a way that better agrees with the experiments conducted in the laboratory.
Показать больше [+] Меньше [-]Homing pigeons as a biomonitor for atmospheric PAHs and PCBs in Guangzhou, a megacity in South China Полный текст
2017
Pei, Yuanyuan | Halbrook, Richard S. | Li, Huizhen | Yau, Ching
The occurrence of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCBs) in urban atmosphere in Guangzhou, China were assessed using homing pigeons as a biomonitor. Contaminant concentrations in lung were significantly higher than those in liver and fat, indicating chemical uptake was mainly through respiratory route. Tricyclic PAHs and low chlorinated PCBs dominated composition of PAHs and PCBs in homing pigeons, similar as their composition in local atmosphere. Different age-dependent bioaccumulation patterns were noted for PAHs and PCBs. For 1-year old homing pigeons, higher levels of PAHs and PCBs in lung and liver tissues were probably ascribed to more intense flying than 5- and 10-year groups. Fat concentrations of PCBs were greater in aged pigeons than 1-year old pigeons, but PAH concentrations in fat slightly decreased in aged pigeons because of relatively fast biotransformation. Overall, homing pigeons could serve as a suitable biomonitor for urban atmospheric contaminants in coastal cities.Homing pigeons could serve as a good biomonitor for PAHs and PCBs in urban atmosphere, yet different biotransformation potential of the chemicals caused different bioaccumulation patterns in pigeon fat.
Показать больше [+] Меньше [-]Estrogenic compound profiles in an urbanized industry-impacted coastal bay and potential risk assessment by pollution indices and multivariative statistical methods Полный текст
2017
Wang, Zaosheng | Li, Rui | Wu, Fengchang | Feng, Chenglian | Ye, Chun | Yan, Changzhou
The occurrence and distribution of target estrogenic compounds in a highly urbanized industry-impacted coastal bay were investigated, and contamination profiles were evaluated by estimating total estradiol equivalents (∑EEQs) and risk quotients (RQs). Phenolic compounds were the most abundant xenoestrogens, but seldom showed contribution to the ∑EEQs. The diethylstilbestrol (DES) and 17α-ethinylestradiol (EE2) were the major contributors followed by 17β-estradiol (E2) in comparison with a slight contribution from estrone (E1) and estriol (E3). Both ∑EEQs and RQs indicated likely adverse effects posed on resident organisms. Further, multivariate statistical method comprehensively revealed pollution status by visualized factor scores and identified multiple “hotspots” of estrogenic sources, demonstrating the presence of complex pollution risk gradients inside and particularly outside of bay area. Overall, this study favors the integrative utilization of pollution indices and factor analysis as powerful tool to scientifically diagnose the pollution characterization of human-derived chemicals for better management decisions in aquatic environments.
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