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Результаты 1511-1520 из 3,991
Using an integrated approach to assess the sediment quality of an estuary from the semi-arid coast of Brazil
2016
Souza, Ivanildo Surini | Araujo, Giuliana Seraphim | Cruz, Ana Carolina Feitosa | Fonseca, Tainá Garcia | Camargo, Julia Beatriz Duarte Alves | Medeiros, Guilherme Fulgêncio | Abessa, Denis M.S.
The Jundiaí–Potengi Estuary (JPE) on the semi-arid coast of Brazil is influenced by multiple sources of pollution. Sediment quality at 10 JPE sites was evaluated through an integrated approach. Rainy and dry seasons were considered. Collected sediments were analyzed for texture, metal, nitrogen, phosphorus concentrations, and toxicity to invertebrates. Geochemical and ecotoxicological data were integrated using qualitative approaches and multivariate techniques. We observed decreased sediment quality in both seasons, particularly in the mid-estuary. In the dry season, the contamination–toxicity relationship was clearer, as hydrological conditions favor contaminant retention within the estuary. Rainy season conditions were found to be worse, since stormwater drainage from agricultural and urban areas carries the contamination into the estuary. Because of the contamination sources and dissolved and particle-bound metal transport, contamination and toxicity did not correlate as clearly in the rainy season. The results suggest that unmeasured contaminants are contributing to JPE sediment degradation.
Показать больше [+] Меньше [-]Spatial variation and provenance of atmospheric trace elemental deposition in Beijing
2016
Zheng, Xiaoxia | Guo, Xiaoyu | Zhao, Wenji | Shu, Tongtong | Xin, Yanan | Yan, Xing | Xiong, Qiulin | Chen, Fantao | Lv, Ming
Atmospheric dry deposition samples were collected in urban and suburban areas of Beijing during a coal-burning period. Chemical characteristics of lanthanoid elements (La–Lu) and five heavy metals (Cr, Co, Mo, Cd, and Pb) were analyzed to determine the variation in spatial scale and deposition provenances. Factor analysis and ternary diagrams were used to identify principle pollution sources. The LaCeSm ternary diagram was used to identify oil refineries using fluid catalytic converters and steel plants, but could not differentiate crustal materials. Lanthanoid characteristic parameters showed similarity between deposition and soil in the local and southwest area in the vicinity of Beijing. Analysis of the five heavy metals enabled discrimination of contaminants originating from human activities. Cd, Pb, and Mo were found to originate from vehicular traffic, whereas Co and Cr originated from industrial emissions and coal combustion. Discriminant analysis established the causes of spatial variation. The result shows that Co, Mo, and Pb can mark the differences between urban and suburban sites. From the PbMoCo plot, it was inferred that the different chemical characters are mainly due to the differing origins of depositions. Deposition samples in suburban areas are principally influenced by soil, chimney soot, and fertilizer, whereas those in urban area are mainly affected by traffic emissions.
Показать больше [+] Меньше [-]Bioassessment of water quality status using a potential bioindicator based on functional groups of planktonic ciliates in marine ecosystems
2016
Xu, Henglong | Yong, Jiang | Xu, Guangjian
The feasibility of a potential ecological indicator based on functional groups of planktonic ciliates for bioassessment of water quality status were studied in a bay, northern Yellow Sea. Samples were biweekly collected at five stations with different water quality status during a 1-year period. The multivariate approach based on “bootstrap-average” analysis was used to summarize the spatial variation in functional structure of the samples. The functional patterns represented a significant spatial variability, and were significantly correlated with the changes of nutrients (mainly nitrate nitrogen, NO3-N), alone or in combination with dissolve oxygen and salinity among five stations. The functional diversity represented a clear spatial variation among five stations, and was found to be significantly related to the nutrient NO3-N. According to the results, we suggest that the ecological parameter based on functional groups of planktonic ciliates may be used as a potential bioindicator of water quality status in marine ecosystems.
Показать больше [+] Меньше [-]The role of social marketing, marine turtles and sustainable tourism in reducing plastic pollution
2016
Eagle, Lynne | Hamann, Mark | Low, David R.
Environmental plastic pollution constitutes a significant hazard to marine turtles, human health and well-being. We describe a transdisciplinary approach to draw together findings from diverse disciplines in order to highlight key environmental pollution problems and their consequences, together with social marketing-based strategies to address the problems. The example of plastic pollution and impacts to marine turtles illustrates the severity of the problem. Wildlife tourism and sustainable tourism activity have not focussed on specific behaviours to change and have had minimal impact on subsequent human behaviour regarding environmental issues, indicating the need for new strategies. Social marketing principles offer promise, but there is a need to investigate the utility of various theoretical foundations to aid the design and implementation of interventions. We offer insight towards using sophisticated multi-method research to develop insights into behaviours and segmentation-based strategies, that can aid the identification of barriers to, and enablers of, sustained behaviour change.
Показать больше [+] Меньше [-]Investigating ozone high levels and the role of sea breeze on its transport
2016
Monteiro, Alexandra | Gama, Carla | Cândido, Marta | Ribeiro, Isabel | Carvalho, David | Lopes, Myriam
This works intends to investigate the ozone episodes reported in three different monitoring sites distributed along the Central region of Portugal (from the coast to inland direction). Ozone data time series are first analysed according to the legislation thresholds fulfilment (information threshold and target value) and two episodes are selected according to the magnitude and simultaneously exceedances at the three sites. The episodes are then analysed in terms of meteorological data (surface and vertical profiles) obtained with the WRF model and also using backtrajectories obtained with the HYSPLIT model. The integration of both results, together with the ozone and NO2 precursor concentration time series, allowed to conclude about the different origin of ozone in the two episodes. A sea breeze circulation is present in the first episode, inducing the transport of this pollutant and its precursors from the coast to inland (about 30 km), which is verified by the wind patterns and vertical profiles and by the daily profile of O3 measured at the three sites. The second episode studied does not show so clearly this influence.
Показать больше [+] Меньше [-]Climate change impacts on marine water quality: The case study of the Northern Adriatic sea
2016
Rizzi, J. | Torresan, S. | Critto, A. | Zabeo, A. | Brigolin, D. | Carniel, S. | Pastres, R. | Marcomini, A.
Climate change is posing additional pressures on coastal ecosystems due to variations in water biogeochemical and physico-chemical parameters (e.g., pH, salinity) leading to aquatic ecosystem degradation.With the main aim of analyzing the potential impacts of climate change on marine water quality, a Regional Risk Assessment methodology was developed and applied to coastal marine waters of the North Adriatic. It integrates the outputs of regional biogeochemical and physico-chemical models considering future climate change scenarios (i.e., years 2070 and 2100) with site-specific environmental and socio-economic indicators.Results showed that salinity and temperature will be the main drivers of changes, together with macronutrients, especially in the area of the Po’ river delta.The final outputs are exposure, susceptibility and risk maps supporting the communication of the potential consequences of climate change on water quality to decision makers and stakeholders and provide a basis for the definition of adaptation and management strategies.
Показать больше [+] Меньше [-]Heavy metals in river and coast sediments of the Jakarta Bay region (Indonesia) — Geogenic versus anthropogenic sources
2016
Sindern, Sven | Tremöhlen, Martin | Dsikowitzky, Larissa | Gronen, Lars | Schwarzbauer, Jan | Siregar, Tuti Hartati | Ariyani, Farida | Irianto, Hari Eko
Sediment geochemistry of the Jakarta region, a densely populated tropical coast, is studied — with particular focus on rivers discharging to Jakarta Bay. Weathering volcanics in the river catchment area control the composition of major elements, As, Cr and in part Cu. In contrast, Zn, Ni, Pb and partly Cu are affected by anthropogenic sources, mainly in central Jakarta City. The data reflect a high variability of local emission sources, among which metal processing industries, fertilizers or untreated animal waste may be important. In particular, the role of street dusts is emphasized. Locally, heavy metals reach levels considered to have adverse biological effects. River discharge leads to anthropogenic enrichment of heavy metals in the coastal sediments. Element data also show geogenic effects on the composition of the coastal sediments, such as mixing of detrital silicates with biogenic carbonates as well as suspended particulate matter from the ocean.
Показать больше [+] Меньше [-]Analysis of polycyclic aromatic hydrocarbons (PAHs) in Lebanese surficial sediments: A focus on the regions of Tripoli, Jounieh, Dora, and Tyre
2016
Manneh, Rima | Abi Ghanem, Carine | Khalaf, Gaby | Najjar, Elie | El Khoury, Bilal | Iaaly, Amal | El Zakhem, Henri
This paper aims to identify the concentrations of PAHs in the sediments of four coastal zones in Lebanon and determine their possible sources and effects. For each region (Tripoli, Jounieh, Dora, and Tyre), sampling, lyophilization, Soxhlet extraction, rotary evaporation, and gas chromatography were performed on 11, 10, 7, and 11 samples, respectively. The total PAHs concentrations ranged from 1.22 to 731.93μg/kg dry weight. The lowest concentrations were found in Tyre and the highest in Dora and Jounieh. The level of PAHs was classified as low to moderate and their source was mainly pyrogenic.
Показать больше [+] Меньше [-]Growth effects of shading and sedimentation in two tropical seagrass species: Implications for port management and impact assessment
2016
Benham, Claudia F. | Beavis, Sara G. | Hendry, Rebecca A. | Jackson, Emma L.
Seagrass meadows in many parts of the globe are threatened by a range of processes including port development, dredging and land clearing in coastal catchments, which can reduce water clarity and increase sedimentation pressure. As rates of seagrass loss increase, there is an urgent need to understand the potential impacts of development on these critical species. This research compares the effects of shading and burial by fine sand on two seagrass species Zostera muelleri and Halophila ovalis in Port Curtis Bay, an industrial harbour located on the continental margin adjacent to the Great Barrier Reef Heritage Area, Australia. The research finds that shading in combination with burial causes a significant decline in growth rates in both species, but that burial ≥10mm reduces growth rates to a greater extent than shading. The paper concludes by discussing the implications of these findings for port management and impact assessment.
Показать больше [+] Меньше [-]Organochlorine compounds in surface sediments from the northern coast of Cyprus, Eastern Mediterranean: Levels, possible sources and potential risk
2016
Kucuksezgin, F. | Pazi, I. | Gonul, L.T. | Duman, M.
Organochlorines (OCs) were determined in sediments collected from different regions of northern coast of Cyprus. The OCPs and Aroclors had a wide range from 2.78 to 306 and 15 to 325ngg−1, respectively. The highest level was found at Yedi Dalga site. DDE was the most abundant compound. The ratios of metabolites to parent DDT showed that DDTs were derived mostly from the aged and weathered inputs. Comparing our results with the previous studies showed that POPs in sediments were found to be lower than those in samples for Mediterranean and Black Sea coasts. The SQG implied that, Aroclor1254 exceeded the TEL values, showing that adverse biological effects are expected occasionally at some of the sediment samples. DDTs were dominant and more ecotoxicological concern in the northern Cyprus. Altogether, it may be summarized that DDTs will impose ecologically hazardous impacts in the sedimentary environment at the present.
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