Уточнить поиск
Результаты 661-670 из 1,545
Trace metal pollution and its influence on the community structure of soft bottom molluscs in intertidal areas of the Dar es Salaam coast, Tanzania Полный текст
2012
Rumisha, Cyrus | Elskens, Marc | Leermakers, Martine | Kochzius, Marc
The influence of trace metal pollution on the community structure of soft bottom molluscs was investigated in intertidal areas of the Dar es Salaam coast. Significant enrichment of As, Mn, Mo, Sb, and Zn in sediments was recorded. Redundancy analysis indicated that trace metal pollution contributed 68% of the variation in community structure. Monte Carlo permutation test showed that As and Sb contributed significantly to variation in species composition. T-value biplots and van Dobben circles showed that the gastropods Acteon fortis, Assiminea ovata, and Littoraria aberrans, were negatively affected by As and Sb, while the bivalve Semele radiata and the gastropod Conus litteratus were only negatively affected by As. Bioaccumulation of As, Cd, Cu, Mo and Zn occurred in the bivalve Mactra ovalina and the gastropod Polinices mammilla. This calls for regular monitoring and management measures.
Показать больше [+] Меньше [-]Improved water quality in response to pollution control measures at Masan Bay, Korea Полный текст
2012
Chang, Won Keun | Ryu, Jongseong | Yi, Yoonju | Lee, Won-Chan | Lee, Chan-Won | Kang, Daeseok | Lee, Chang Hee | Hong, Seongjin | Nam, Jungho | Khim, Jong Seong
The total pollution load management system (TPLMS) was first applied in 2007 to the highly developed Masan Bay watershed, Korea. To evaluate the effect of TPLMS on water quality improvement, we analyzed the water qualities in rivers and bay during 2005–2010, targeting chemical oxygen demand (COD), suspended sediment (SS), total nitrogen (TN), and total phosphorus (TP) loads. Land-based pollutant loading all decreased during this period, with a significant reduction in COD and SS loads (p<0.01). The COD reduction in seawater, following the TPLMS implementation, was also significant (p<0.01). Time-lagged responses in COD and Chl-a supported an estimated seawater residence time of ∼1month. Land-based nutrient loads were also significantly reduced for TN (p<0.01) and TP (p<0.05), however, significant reductions were not observed in the bay, indicating potential alternative nutrient inputs from non-point sources into the bay system.
Показать больше [+] Меньше [-]Effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on microbial community dynamics during assays of oil spill bioremediation: A microcosm study Полный текст
2012
Cappello, Simone | Genovese, Maria | Della Torre, Camilla | Crisari, Antonella | Hassanshahian, Mehdi | Santisi, Santina | Calogero, Rosario | Yakimov, Michail M.
Microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on microbial community dynamics. An experimental seawater microcosm, supplemented with crude oil and EPS₂₀₀₃ (SW+OIL+EPS₂₀₀₃), was monitored for 15days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out during all experimentation period. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil degradation was monitored by GC–MS analysis. Bioemulsificant addition stimulated an increase of the total bacterial abundance, change in the community structure and activity. The bioemulsificant also increased of 5 times the oil biodegradation rate. The data obtained from microcosm experiment indicated that EPS₂₀₀₃ could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process.
Показать больше [+] Меньше [-]Seasonal variation of polycyclic aromatic hydrocarbons concentrations in urban streams at Niterói City, RJ, Brazil Полный текст
2012
Ribeiro, Angelo Morgado | da Rocha, Camila Coimbra Martins | Franco, Caroline Fernandes Jaegger | Fontana, Luiz Francisco | Pereira Netto, Annibal D.
Polycyclic aromatic hydrocarbons (PAHs) were determined in water samples collected in two streams and a lake located at Niteroi City, Rio de Janeiro State, Brazil between October 2008 and September 2009. Samples were extracted using liquid–liquid extraction and analyzed using high performance liquid chromatography with fluorescence detection. The limits of quantification were sufficiently low to accomplish PAH determination below the maximum concentration levels established by the Brazilian (50ng/L) and USEPA legislations, with recoveries larger than 81.6%. Phenanthrene, fluoranthene, pyrene and benz[a]anthracene predominated among PAHs. Total concentrations of PAHs were well correlated with rainfall indicating a possible role of runoff to local pollution of water by PAHs and showed a seasonal variation in wet and dry seasons. Our results highlight the contribution of the widespread streams located around Guanabara Bay to the PAH burden found in its waters.
Показать больше [+] Меньше [-]A historical review and bibliometric analysis of research on estuary pollution Полный текст
2012
Sun, Jinshui | Wang, Ming-Huang | Ho, Yuh-Shan
A bibliometric method based on Science Citation Index-Expanded published by the Thomson Reuters was used to quantitatively assess the global estuary pollution research from 1991 to 2010. The main results were as follows: there had been a notable growth trend in publication outputs. Marine Pollution Bulletin was the most active journal. Environmental sciences were top popular subject categories. USA produced the most single, internationally collaborative, first authored and corresponding authored articles. The Chinese Academy of Sciences was the most productive institute for the total articles. Sediment was the most active research topic, which ranked 1st in article title, article abstract, author keyword, and KeyWords Plus analysis, respectively. Heavy metals received stable focus on a high degree in the field of estuary pollution research. Mostly refractory organic compounds (e.g. PAHs) became more active. Biomarkers and bioaccumulation both were active issues. Eutrophication of estuarine waters receives increasing concern in estuary pollution research.
Показать больше [+] Меньше [-]Airborne sensors for detecting large marine debris at sea Полный текст
2012
Veenstra, Timothy S. | Churnside, James H.
The human eye is an excellent, general-purpose airborne sensor for detecting marine debris larger than 10cm on or near the surface of the water. Coupled with the human brain, it can adjust for light conditions and sea-surface roughness, track persistence, differentiate color and texture, detect change in movement, and combine all of the available information to detect and identify marine debris. Matching this performance with computers and sensors is difficult at best. However, there are distinct advantages over the human eye and brain that sensors and computers can offer such as the ability to use finer spectral resolution, to work outside the spectral range of human vision, to control the illumination, to process the information in ways unavailable to the human vision system, to provide a more objective and reproducible result, to operate from unmanned aircraft, and to provide a permanent record that can be used for later analysis.
Показать больше [+] Меньше [-]Metal concentrations in selected tissues and main prey species of the annulated sea snake (Hydrophis cyanocinctus) in the Hara Protected Area, northeastern coast of the Persian Gulf, Iran Полный текст
2012
Rezaie-Atagholipour, Mohsen | Riyahi-Bakhtiari, Alireza | Sajjadi, Mirmasoud | Yap, Chee Kong | Ghaffari, Sanaz | Ebrahimi-Sirizi, Zohreh | Ghezellou, Parviz
This study is the first detailed ecotoxicological study of the annulated sea snake, Hydrophis cyanocinctus. Concentrations of lead, cadmium, nickel and vanadium were evaluated in muscle, liver, kidney, skin and blood of the annulated sea snake (H. cyanocinctus) and in the whole bodies of its main prey species (Periophthalmus waltoni and Boleophthalmus dussumieri) in the Hara Protected Area, the Persian Gulf. The mean concentrations of lead and vanadium were highest in the kidney, which identified the kidney as a target organ for metals in sea snakes as it is in other reptilian groups. Mean concentrations of cadmium and nickel were highest in the liver and skin, respectively. Mean cadmium concentrations were significantly higher in the liver compared to prey species, which indicated that prey items may be a source of cadmium for the annulated sea snake in the study area. Data presented here may be considered as a baseline for further ecotoxicological studies in sea snakes.
Показать больше [+] Меньше [-]Laboratory testing protocol for the impact of dispersed petrochemicals on seagrass Полный текст
2012
Wilson, K.G. | Ralph, P.J.
To improve the effectiveness of oil spill mitigation, we developed a rapid, logistically simple protocol to detect petrochemical stress on seagrass. Sections of leaf blades from Zostera muelleri subsp. capricorni were exposed to the water accommodated fraction (WAF) of non-dispersed and dispersed Tapis crude oil and fuel oil (IFO-380) for 5h. Photosynthetic health was monitored by assessing changes in effective quantum yield of photosystem II (ΔF/Fₘ ′) and chlorophyll a pigment concentrations. Loss of total petroleum hydrocarbons (TPH) was measured using an oil-in-water fluorometer, whilst GC–MS analyses quantified the hydrocarbon components within each treatment. Few significant differences were detected in the chlorophyll a pigment analyses; however, ΔF/Fₘ ′ appeared sensitive to petrochemical exposure. Dispersing both types of oil resulted in a substantial increase in the TPH of the WAF and was generally correlated with a greater physiological impact to the seagrass health, compared with the oil alone.
Показать больше [+] Меньше [-]Razorbills (Alca torda) as bioindicators of mercury pollution in the southwestern Mediterranean Полный текст
2012
Espín, Silvia | Martínez-López, Emma | Gómez-Ramírez, Pilar | María-Mojica, Pedro | García-Fernández, Antonio J.
Levels of mercury (Hg) were analyzed in the tissues of 50 Razorbills (Alca torda), from the Mediterranean area, which had drowned in fishing nets. The mercury distribution pattern in tissues was similar to those of other studies (liver>feather vane>kidney>muscle>brain>feather shaft), with mercury concentrations of 2.85±0.90, 2.66±1.60, 2.23±0.87, 1.54±0.54, 1.48±0.54 and 1.30±0.76mg/kg (dry weight), respectively. It could be considered that Razorbills in the southwestern Mediterranean were chronically exposed to relatively low levels of MeHg, probably below 0.5ppm, via dietary intake. We have proposed prediction equations for brain and kidney Hg concentrations using feather shafts as non-invasive samples. This work provides a solid understanding of Razorbill Hg exposure both in their wintering and breeding grounds, and shows that this species can be useful for assessing marine environmental health in the Mediterranean area.
Показать больше [+] Меньше [-]Persistent organic pollutants in juvenile Magellan penguins (Spheniscus magellanicus) found on the northern shore of the state of São Paulo and southern shore of the state of Rio de Janeiro, Brazil Полный текст
2012
Baldassin, Paula | Taniguchi, Satie | Gallo, Hugo | Silva, Reinaldo José | Montone, Rosalinda Carmela
In the present study, persistent organic pollutants (POPs) were determined in 25 livers from Magellanic penguins, Spheniscus magellanicus, found on the state of São Paulo and Rio de Janeiro (Brazil). The following concentrations of POPs (wet weight) were found: ∑ PCBs: 18.9–775.8ngg⁻¹; ∑ DDTs: 2.3–275ngg⁻¹; and ∑ HCHs: 1.0–11.8ngg⁻¹. Among the PCBs, there was a predominance of hexachlorobiphenyls (138 and 153) and heptachlorobiphenyls (180 and 187). Among the organochlorines, DDT predominated. Through histopathologic exams a positive correlation was found between HCB and cardiovascular failure (p=0.012), as HCB values (wet weight) were 6.33–96.49ngg⁻¹ for positive animals and 2.45–19.63ngg⁻¹ for negative animals. Studies on POPs in Magellan penguins contribute to a better understanding of the distribution and trends of these pollutants in the western South Atlantic Ocean.
Показать больше [+] Меньше [-]