خيارات البحث
النتائج 521 - 530 من 2,512
Halogenated persistent organic pollutants in relation to trophic level in deep sea fish النص الكامل
2014
Webster, Lynda | Russell, Marie | Walsham, Pam | Hussy, Ines | Lacaze, Jean-Pierre | Phillips, Lesley | Dalgarno, Eric | Packer, Gill | Neat, Francis | Moffat, Colin F.
The bioaccumulation of persistent organic pollutants (POPs) in deep sea fish from the Rockall fishing area was investigated. Predator and prey species were analysed for stable isotopes, fatty acids, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). δ15N indicated that black scabbard was at the highest trophic level and the prey the lowest. The fatty acid signatures indicated that black scabbard and black dogfish fed at a higher trophic level compared to the roundnose grenadier. PCBs and PBDEs were detected in the liver of all three predator species. PCB concentrations were significantly higher in the roundnose grenadier, possibly due to their longer life span. PCB concentrations were compared to OSPAR assessment criteria, concentrations were above background but below Environmental Assessment Criteria for all but one congener. PCB concentrations were below food safety levels in the flesh, but exceeded the limit for liver in the roundnose grenadier and black dogfish.
اظهر المزيد [+] اقل [-]An analysis of organic matter sources for surface sediments in the central South Yellow Sea, China: Evidence based on macroelements and n-alkanes النص الكامل
2014
Zhang, Shengyin | Li, Shuanglin | Dong, Heping | Zhao, Qingfang | Lu, Xinchuan | Shi, Ji’an
By analyzing the composition of n-alkane and macroelements in the surface sediments of the central South Yellow Sea of China, we evaluated the influencing factors on the distribution of organic matter. The analysis indicates that the distribution of total organic carbon (TOC) was low in the west and high in the east, and TOC was more related to Al2O3 content than medium diameter (MD). The composition of n-alkanes indicated the organic matter was mainly derived from terrestrial higher plants. Contributions from herbaceous plants and woody plants were comparable. The comprehensive analysis of the parameters of macroelements and n-alkanes showed the terrestrial organic matter in the central South Yellow Sea was mainly from the input of the modern Yellow River and old Yellow River. However, some samples exhibited evident input characteristics from petroleum sources, which changed the original n-alkanes of organic matter in sediments.
اظهر المزيد [+] اقل [-]Characterization and source identification of organic matter in view of land uses and heavy rainfall in the Lake Shihwa, Korea النص الكامل
2014
Lee, Yeonjung | Hur, Jin | Shin, Kyung-Hoon
The characteristics and sources of organic matter in water of the Lake Shihwa, which receives inputs from rural, urban, and industrial areas, were evaluated by examining the biodegradable organic carbon concentration, fluorescence spectra, and carbon and nitrogen isotope ratios, especially during rainy season and dry season. The organic matter transported from rural areas was of refractory nature, while that of industrial origin decomposed rapidly. As compared to the dry season, the organic matter in the rainy season was characterized by a reduced labile fraction. During the dry season, the autochthonous organic matter dominated in the lake, however, the contributions of allochthonous organic sources by industrial and rural areas significantly increased at rainy season. This investigation revealed that the transport of organic matter of anthropogenic origin to the Lake Shihwa was mainly influenced by heavy rainfall. Moreover, each anthropogenic source could differently influence the occurrence of organic matter in water of the Lake Shihwa.
اظهر المزيد [+] اقل [-]Carcinogenic and mutagenic potencies for different PAHs sources in coastal sediments of Shandong Peninsula النص الكامل
2014
Li, Guo Liang | Lang, Yin-hai | Gao, Mao-sheng | Yang, Wei | Peng, Peng | Wang, Xiao-mei
In this study, sources of PAHs in coastal sediments of Shandong Peninsula were apportioned using the chemical mass balance (CMB) model, and source apportionment of carcinogenic and mutagenic potencies was conducted combining CMB with the formula of benzo(a)pyrene carcinogenic equivalent (BaPTEQ) and BaP mutagenic equivalent (BaPMEQ) concentration. Total concentrations of sixteen PAHs in sediment ranged from 181.2ngg−1 to 303.6ngg−1, and concentrations of eight carcinogenic PAHs (cPAHs) varied from 98.8ngg−1 to 141.1ngg−1. The BaP played a dominant role for carcinogenic and mutagenic potencies of PAHs, although the IND showed the highest concentration level. The vehicular sources made the highest contribution to BaPTEQ (57.7%) and BaPMEQ (55.5%), while petrogenic source, the highest contributor for PAHs (39.4%), provided the lowest contribution to BaPTEQ (1.1%) and BaPMEQ (1.5%). Besides, the ecotoxicological evaluation, based on Sediment Quality Guidelines (SQGs), showed low ecological risks generally.
اظهر المزيد [+] اقل [-]The “one-out, all-out” principle entails the risk of imposing unnecessary restoration costs: A study case in two Mediterranean coastal lakes النص الكامل
2014
Prato, S. | La Valle, P. | De Luca, E. | Lattanzi, L. | Migliore, G. | Morgana, J.G. | Munari, C. | Nicoletti, L. | Izzo, G. | Mistri, M.
The Water Framework Directive uses the “one-out, all-out” principle in assessing water bodies (i.e., the worst status of the elements used in the assessment determines the final status of the water body). In this study, we assessed the ecological status of two coastal lakes in Italy. Indices for all biological quality elements used in transitional waters from the Italian legislation and other European countries were employed and compared. Based on our analyses, the two lakes require restoration, despite the lush harbor seagrass beds, articulated macrobenthic communities and rich fish fauna. The “one-out, all-out” principle tends to inflate Type I errors, i.e., concludes that a water body is below the “good” status even if the water body actually has a “good” status. This may cause additional restoration costs where they are not necessarily needed. The results from this study strongly support the need for alternative approaches to the “one-out, all-out” principle.
اظهر المزيد [+] اقل [-]Metal contamination of estuarine intertidal sediments of Moreton Bay, Australia النص الكامل
2014
Morelli, Guia | Gasparon, Massimo
Trace element concentrations in surface intertidal sediments were analyzed to assess the level of contamination along the western side of Moreton Bay (Australia). The environmental risks posed by metals were evaluated using sediment quality guidelines, the Risk Assessment Code (RAC) and enrichment relative to background levels. Chromium, Ni, and Cu are the main contributors to sediment pollution. Sediments are also enriched in Zn, Cd and Pb by 1.5–3 times the regional background. Zinc, Cd and Co may pose high to very high risk to the aquatic biota due to their potential bioavailability, while Ni, As, Cu, Pb and Cr may pose medium risk at some of the investigated sites. Results emphasize the importance of using different methods for the assessment of sediment pollution at an estuarine site.
اظهر المزيد [+] اقل [-]The effect of suspended sediment on fertilization success in the urchin Evechinus chloroticus: Analysis of experimental data using hierarchical Bayesian methods النص الكامل
2014
Miller, S.L. | Richardson, K. | Edwards, P.A.
Terrestrial sediments are a significant stressor on coastal ecosystems, with both suspended and deposited sediment having adverse effects on aquatic organisms. However, information on the effect of suspended sediments on fertilization success for urchin species is lacking. Using sediment levels similar to those encountered in situ, a controlled experiment was conducted to test whether suspended sediment affects fertilization success in the urchin Evechinus chloroticus. Analyses used generalized linear mixed models (GLMMs) and hierarchical Bayesian (HB) regression. Both approaches showed a significant decrease in fertilization success with increased suspended sediment levels. Uncertainties in estimates were narrower for HB models, suggesting that this approach has advantages over GLMMs for sparse data problems sometimes encountered in laboratory experiments. Given future global change scenarios, this work is important for predicting the effects of stressors such as sedimentation that may ultimately impact marine populations.
اظهر المزيد [+] اقل [-]Hierarchy of factors exerting an impact on nutrient load of the Baltic Sea and sustainable management of its drainage basin النص الكامل
2014
Kiedrzyńska, Edyta | Jóźwik, Adam | Kiedrzyński, Marcin | Zalewski, Maciej
The aim of the paper was to evaluate 23 catchment factors that determine total phosphorus and total nitrogen load to the Baltic Sea. Standard correlation analysis and clustering were used. Both phosphorus and nitrogen loads were found to be positively related to the number of pigs and the human population associated with wastewater treatment plants (WWTPs) per km2, while the number of cattle and agricultural area were found to influence nitrogen rather than phosphorus load, and the area of forests is negatively related to loads of both nutrients. Clustering indicates an overall north–south pattern in the spatial co-occurrence of socio-ecological factors, with some exceptions discussed in the paper. Positive steps in the Baltic Sea region have already been taken, but much remains to be done. The development of coherent response policies to reduce eutrophication in the Baltic Sea should be based on a comprehensive knowledge base, an appropriate information strategy and learning alliance platform in each drainage river catchments.
اظهر المزيد [+] اقل [-]Persistent organic pollutants in liver of Brazilian sharpnose shark (Rhizoprionodon lalandii) from southeastern coast of Brazil النص الكامل
2014
Cascaes, M.J. | Oliveira, R.T. | Ubarana, M.M. | Sato, R.M. | Baldassin, P. | Colabuono, F.I. | Leonel, J. | Taniguchi, S. | Weber, R.R.
In the present study, persistent organic pollutants (POPs) were determined in 14 livers from specimens of the Brazilian sharpnose shark (Rhizoprionodon lalandii), which is an important economic resource for small-scale fisheries on the southeastern coast of Brazil. The following concentrations (lipid weight) of POPs were found: ∑PCBs: 1019±267ngg−1; ∑DDTs: 111±40ngg−1 and ∑PBDEs: 10.4±4.78. PCB 153 made the greatest contribution to ∑PCB (21.4%), followed by PCB 138 (14.6%) and PCB 180 (9.94%). Among chlorinated pesticides, only the p,p′-DDE and p,p′-DDD isomers had concentrations above the detection limit. Moreover, levels above the detection limit were found only for PBDE congeners 47 and 100 (BDEs 47>99). On average, BDE 47 accounted for 88% of the total PBDE load. The feeding habits of the Brazilian sharpnose shark close to the Brazilian coastline are likely the most important difference regarding the accumulation of POPs in comparison to oceanic species that feed in deeper waters. Thus, this species may be used to evaluate the pollution of coastal areas as well as human exposure to contaminants, as the Brazilian sharpnose shark is a frequently used for human consumption. Further studies in other areas of Brazil and involving other species are needed to clarify the mechanisms and potential impact of POPs, which can affect the biology of different organisms and cause population declines.
اظهر المزيد [+] اقل [-]Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments النص الكامل
2014
Quilliam, Richard S. | Jamieson, Julie | Oliver, David M.
Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments النص الكامل
2014
Quilliam, Richard S. | Jamieson, Julie | Oliver, David M.
The revised Bathing Water Directive (rBWD) introduces more stringent standards for microbial water quality and promotes more pro-active management of the beach environment through the production of a bathing water profile (BWP). The aim of this study was to determine whether living seaweeds in the littoral zone are colonised by faecal indicator organisms (FIOs), and to quantify the survival dynamics of waterborne Escherichia coli in microcosms containing senescing seaweeds. Living seaweed (Fucus spiralis) was not associated with FIO colonisation, although could be providing a protected environment in the underlying sand. Senescing seaweeds enhanced waterborne E. coli survival compared to plastic debris, with the brown seaweed Laminaria saccharina facilitating greater E. coli persistence than either Chondrus crispus or Ulva lactuca. This has important implications for FIO survival on bathing beaches as the majority of beach-cast biomass is composed of brown seaweeds, which could support significant levels of FIOs.
اظهر المزيد [+] اقل [-]Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments النص الكامل
2014
Quilliam, Richard | Jamieson, Julie | Oliver, David | Biological and Environmental Sciences | University of Stirling | Biological and Environmental Sciences | 0000-0001-7020-4410 | 0000-0002-6200-562X
The revised Bathing Water Directive (rBWD) introduces more stringent standards for microbial water quality and promotes more pro-active management of the beach environment through the production of a bathing water profile (BWP). The aim of this study was to determine whether living seaweeds in the littoral zone are colonised by faecal indicator organisms (FIOs), and to quantify the survival dynamics of waterborne Escherichia coli in microcosms containing senescing seaweeds. Living seaweed (Fucus spiralis) was not associated with FIO colonisation, although could be providing a protected environment in the underlying sand. Senescing seaweeds enhanced waterborne E. coli survival compared to plastic debris, with the brown seaweed Laminaria saccharina facilitating greater E. coli persistence than either Chondrus crispus or Ulva lactuca. This has important implications for FIO survival on bathing beaches as the majority of beach-cast biomass is composed of brown seaweeds, which could support significant levels of FIOs.
اظهر المزيد [+] اقل [-]