خيارات البحث
النتائج 781 - 790 من 2,513
Source apportionment of polycyclic aromatic hydrocarbons in soils of wetlands in the Liao River Delta, Northeast China النص الكامل
2014
Ma, Chuanliang | Ye, Siyuan | Lin, Tian | Ding, Xigui | Yuan, Hongming | Guo, Zhigang
The polycyclic aromatic hydrocarbons (PAHs) of 55 surface soil samples from the wetlands in the Liao River Delta, Northeast China were measured in order to apportion their sources. The total concentrations of 16 US EPA priority PAHs and alkyl-PAHs in this region ranged 106–3148ngg−1 (dry weight) (average: 550±565ngg−1) and 54–5564ngg−1 (average: 517±838ngg−1), respectively. Based on the positive matrix factorization analysis of alkylated and parent PAHs, six sources of PAHs were identified including petroleum (23%), biomass burning (23%), air–soil exchange (18%), coal combustion (17%), traffic emission (14%) and biogenic origin (6%). The positive correlation between low molecular weight (LMW) PAHs and TOC contents could demonstrate a potential positive influence of TOC on the accumulations of LMW PAHs in soils by the air–soil exchange. The petrogenic PAHs may pose a limited harmful effect on aquatic organisms although they were abundant in the area.
اظهر المزيد [+] اقل [-]Assessment of heavy metal impact on sediment quality of the Xiaoqinghe estuary in the coastal Laizhou Bay, Bohai Sea: Inconsistency between two commonly used criteria النص الكامل
2014
Zhuang, Wen | Gao, Xuelu
Surface sediments in the Xiaoqinghe estuary, southwestern coastal Laizhou Bay, were examined to assess the bio-toxic risk of heavy metals (Cd, Cu, Ni, Pb and Zn) with the effects range-low and effects range-median guidelines (ERL–ERMs) and the concentration ratio of simultaneously extractable metals to acid volatile sulfides ([SEM]/[AVS]). Based on the ERL–ERM guidelines, bio-toxic effect caused by Cu, Ni, Pb and Zn could be expected in the riverine surface sediments of the Xiaoqinghe estuary; and the surface sediments in the marine area were in good quality and only Ni might cause bio-toxic effect occasionally. The AVS–SEM guidelines revealed that no bio-toxic effect could be caused by any of the studied metals in both the riverine and marine sediments, since there were excess sulfides in surface sediments which could form water-insoluble substances with free metal ions and reduce the bioavailability of heavy metals.
اظهر المزيد [+] اقل [-]Marine debris ingestion by coastal dolphins: What drives differences between sympatric species? النص الكامل
2014
Di Beneditto, Ana Paula Madeira | Ramos, Renata Maria Arruda
This study compared marine debris ingestion of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in a sympatric area in Atlantic Ocean. Among the 89 stomach contents samples of P. blainvillei, 14 (15.7%) contained marine debris. For S. guianensis, 77 stomach contents samples were analyzed and only one of which (1.30%) contained marine debris. The debris recovered was plastic material: nylon yarns and flexible plastics. Differences in feeding habits between the coastal dolphins were found to drive their differences regarding marine debris ingestion. The feeding activity of P. blainvillei is mainly near the sea bottom, which increases its chances of ingesting debris deposited on the seabed. In contrast, S. guianensis has a near-surface feeding habit. In the study area, the seabed is the main zone of accumulation of debris, and species with some degree of association with the sea bottom may be local bioindicators of marine debris pollution.
اظهر المزيد [+] اقل [-]Marine wildlife entanglement: Assessing knowledge, attitudes, and relevant behaviour in the Australian community النص الكامل
2014
Pearson, Elissa | Mellish, Sarah | Sanders, Ben | Litchfield, Carla
Marine debris remains a global challenge, with significant impacts on wildlife. Despite this, there is a paucity of research examining public understanding about marine wildlife entanglement [MWE], particularly within an Australian context. The present study surveyed two hundred and thirteen participants across three coastal sites to assess familiarity with MWE and the effectiveness of a new community education initiative ‘Seal the Loop’ [STL]. Results revealed attitudes toward marine wildlife were very positive (M 40.5, SD 4.12); however 32% of participants were unable to correctly explain what MWE is and risks to wildlife were under-estimated. STL may be one method to enhance public understanding and engagement-if community familiarity with the program can be increased. For those aware of STL (<13% of the sample at the time of the study), findings revealed this was having a positive impact (e.g. learning something new, changed waste disposal behaviours).
اظهر المزيد [+] اقل [-]Comparing plastic ingestion in juvenile and adult stranded short-tailed shearwaters (Puffinus tenuirostris) in eastern Australia النص الكامل
2014
Acampora, Heidi | Schuyler, Qamar A. | Townsend, Kathy A. | Hardesty, Britta Denise
Numerous species of seabirds have been shown to ingest anthropogenic debris, but few studies have compared ingestion rates between adults and juveniles of the same species. We investigated marine debris ingestion by short-tailed shearwaters (Puffinus tenuirostris) obtained through two stranding events on North Stradbroke Island, Australia in 2010 (n=102; adult) and 2012 (n=27; juveniles). Necropsies were conducted and solid contents found in guts were categorized into type and color. Over 67% of birds ingested anthropogenic debris: 399 pieces of debris were identified. We found no significant relationship between body condition of birds which had ingested anthropogenic debris and those that had not. Juvenile birds were more likely to ingest debris than were adult birds and juveniles ingested significantly more pieces of debris than did adults. Male and female birds ingested similar amounts and weights of debris. To determine if P. tenuirostris actively selects for certain types of debris, we compared ingested debris to samples obtained from boat-based tows. Significant differences were found, suggesting that the birds select for hard plastic, rubber and balloons.
اظهر المزيد [+] اقل [-]Distribution, sources and ecological risk assessment of PAHs in surface sediments from Guan River Estuary, China النص الكامل
2014
He, Xinran | Pang, Yong | Song, Xiaojuan | Chen, Binlin | Feng, Zhihua | Ma, Yuqin
The contamination of surface sediments in Guan River Estuary, China, by polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. Total concentrations of 21 PAHs ranged from 90 to 218ng/g with an average of 132.7ng/g, which is relatively low in comparison with other estuaries around the world. PAH concentrations appeared to be positively correlated with clay content and negatively correlated with sediment grain size. Source identification implied that the PAHs originated mainly from pyrolytic sources. However, source patterns may be continuously changed to a petrogenic origin due to the heavy ship traffic and continuous discharge of oily sewage in this area. The PAH levels were also compared with international Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated low negative effects for most individual PAHs. However, toxic effects related to FLO would occur occasionally in most locations in the estuary.
اظهر المزيد [+] اقل [-]Measuring bioavailable metals using diffusive gradients in thin films (DGT) and transplanted seaweed (Fucus vesiculosus), blue mussels (Mytilus edulis) and sea snails (Littorina saxatilis) suspended from monitoring buoys near a former lead–zinc mine in West Greenland النص الكامل
2014
Søndergaard, Jens | Bach, Lis | Gustavson, Kim
Measuring loads of bioavailable metals is important for environmental assessment near mines and other industrial sources. In this study, a setup of monitoring buoys was tested to assess loads of bioavailable metals near a former Pb–Zn mine in West Greenland using transplanted seaweed, mussels and sea snails. In addition, passive DGT samplers were installed. After a 9-day deployment period, concentrations of especially Pb, Zn and Fe in the species were all markedly elevated at the monitoring sites closest to the mine. Lead concentrations in all three species and the DGT-Pb results showed a significant linear correlation. Zinc and Fe concentrations were less correlated indicating that the mechanisms for Zn and Fe accumulation in the three species are more complex. The results show that there is still a significant load of metals from the mine and that such buoys can be an adequate method to assess present loads of bioavailable metals.
اظهر المزيد [+] اقل [-]Mercury concentrations in breast feathers of three upper trophic level marine predators from the western Aleutian Islands, Alaska النص الكامل
2014
Kaler, Robb S.A. | Kenney, Leah A. | Bond, Alexander L. | Eagles-Smith, Collin A.
Mercury (Hg) is a toxic element distributed globally through atmospheric transport. Agattu Island, located in the western Aleutian Islands, Alaska, has no history of point-sources of Hg contamination. We provide baseline levels of total mercury (THg) concentrations in breast feathers of three birds that breed on the island. Geometric mean THg concentrations in feathers of fork-tailed storm-petrels (Oceanodroma furcata; 6703±1635, ng/g fresh weight [fw]) were higher than all other species, including snowy owl (Bubo scandiacus; 2105±1631, ng/g fw), a raptor with a diet composed largely of storm-petrels at Agattu Island. There were no significant differences in mean THg concentrations of breast feathers among adult Kittlitz’s murrelet (Brachyramphus brevirostris; 1658±1276, ng/gfw) and chicks (1475±671, ng/gfw) and snowy owls. The observed THg concentrations in fork-tailed storm-petrel feathers emphasizes the need for further study of Hg pollution in the western Aleutian Islands.
اظهر المزيد [+] اقل [-]Effects of the sandbar breaching on hydrobiological parameters and zooplankton communities in the Senegal River Estuary (West Africa) النص الكامل
2014
Champalbert, Gisèle | Pagano, Marc | Arfi, Robert | Chevalier, Cristèle
This study describes the changes in hydrology, zooplankton communities and abundance in the Senegal River Estuary (SRE) before and after the breaching of the sandbar in October 2003. Samples were taken in 2003 at 3 stations located upstream (DI), in mid estuary (HY) and downstream (RM), and in 2005 at the same stations (RM becoming Old River Mouth: ORM), plus the new river mouth (NRM) resulting from the morphological evolution of the SRE.The study showed marked seasonal variations that affected the structure and distribution of zooplankton as well as major changes caused by the sandbar opening:–increased marine influence throughout the whole SRE,–changes in the horizontal gradients,–arrival of euryhaline species and increase in meroplankton, in particular decapod larvae,–transformation of the ORM area into a slackwater area with limited exchanges and the highest zooplankton numbers during high waters.
اظهر المزيد [+] اقل [-]Expansion of an invasive coral species over Abrolhos Bank, Southwestern Atlantic النص الكامل
2014
Costa, Thiago J.F. | Pinheiro, Hudson T. | Teixeira, João Batista | Mazzei, Eric F. | Bueno, Leonardo | Hora, Mike S.C. | Joyeux, Jean-Christophe | Carvalho Filho, Alfredo | Amado-Filho, Gilberto | Sampaio, Claudio L.S. | Rocha, Luiz A.
Invasive coral species of the genus Tubastraea have been increasingly recorded in Southwestern Atlantic waters since the 1980s. Their invasion and infestation are mainly related to port and oil exploration activities. For the first time the presence of Tubastraea tagusensis colonies is reported in Espírito Santo State, colonizing a port shore area, and incrusting oil/gas platform structures situated in the southern Abrolhos Bank, which is part of the most important coral reef system of the South Atlantic Ocean. Tubastraea colonies exhibit fast growth and high recruitment rates, and colonized 40% of the analyzed structures in just four years. The projection of port and oil/gas industry growth for the Espírito Santo State (more than 300%) highlights an alert to the dispersal of this alien species to natural areas.
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