خيارات البحث
النتائج 611 - 620 من 1,539
Laboratory testing protocol for the impact of dispersed petrochemicals on seagrass
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.
اظهر المزيد [+] اقل [-]Spatial distribution and source apportionment of PAHs in surficial sediments of the Yangtze Estuary, China
2012
Li, Baohua | Feng, Chenghong | Li, Xue | Chen, Yaxin | Niu, Junfeng | Shen, Zhenyao
Spatial distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Yangtze Estuary, especially the North Branch, have been fully investigated. PAH concentrations increased with the descending distance from the inner estuary to the adjacent sea, and varied significantly in various estuarine regions. Water currents (e.g., river runoff and ocean current) greatly affected the distribution pattern. In addition, ambient sewage and traffic also contributed to the PAH pollution in the estuary. In the adjacent sea, PAH values along the −20m isobath were higher than those along the −10m isobath due to the “marginal filter” phenomenon formed by different water currents. In most sites, PAHs had poor correlations with sediment size, but had positive correlations with total organic carbon. Based on the qualitative and quantitative analysis results, PAH sources were proved to be mainly from a mixture of petroleum combustion, biomass, and coal combustion.
اظهر المزيد [+] اقل [-]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
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.
اظهر المزيد [+] اقل [-]Use of species sensitivity distributions to predict no-effect concentrations of an antifouling biocide, pyridine triphenylborane, for marine organisms
2012
Mochida, Kazuhiko | Onduka, Toshimitsu | Amano, Haruna | Ito, Mana | Ito, Katsutoshi | Tanaka, Hiroyuki | Fujii, Kazunori
We used species sensitivity distributions (SSDs) and a Bayesian statistical model to carry out a primary risk assessment for pyridine triphenylborane (PTPB) in Hiroshima Bay, Japan. We used SSDs derived from toxicity values, such as EC₅₀ and LC₅₀, obtained from this study and previous work to calculate hazardous concentrations that should protect 95% and 99% of species (HC₅ and HC₁) and demonstrated that the medians of the HC₅ and HC₁ were 0.78 and 0.17μg/L, respectively. We also used liquid chromatography/mass spectrometry to investigate the occurrence of PTPB in seawater from several coastal sites of Hiroshima Bay and detected PTPB at concentrations of 4.8–21pg/L. Comparison of environmental concentrations to the HC values suggests that the current ecological risk posed by PTPB in Hiroshima Bay is low. This is the first report of the detection of PTPB in the natural marine environment.
اظهر المزيد [+] اقل [-]A historical review and bibliometric analysis of research on estuary pollution
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.
اظهر المزيد [+] اقل [-]Biomarker responses and genotoxicity in the mud snail (Bullacta exarata) as indicators of coastal contamination
2012
An, Li-hui | Zheng, Bing-hui | Wang, Li-jing | Zhang, Yan-Qiang | Chen, Hao | Zhao, Xing-ru | Zhang, Lei | Lei, Kun
In the present study different biomarker responses and genotoxicity were determined in wild mud snails (Bullacta exarata) collected from 3 sampling sites in Bohai Bay in northeastern China, which is a region that is under considerable anthropogenic influence. Significant spatial variability of superoxide dismutase (SOD) and metallothionein (MT)-like proteins were recorded, while glutathione transferase (GST), catalase (CAT), and vitellin-like proteins (Vn’s) were not observed. Furthermore, genomic DNA that was amplified with 4 fluorescence-labeled primer pairs showed variable genetic distances among the 3 wild mud snail populations found in Bohai Bay, which may be correlated with differences in the types of environmental genotoxicants, such as heavy metals and polycyclic aromatic hydrocarbons. This multi-biomarker approach provided an improved understanding of the potential toxicological impact of contaminated sediments on benthic organisms.
اظهر المزيد [+] اقل [-]Evaluation for the ecological quality status of coastal waters in East China Sea using fuzzy integrated assessment method
2012
Wu, H.Y. | Chen, K.L. | Chen, Z.H. | Chen, Q.H. | Qiu, Y.P. | Wu, J.C. | Zhang, J.F.
This research presented an evaluation for the ecological quality status (EcoQS) of three semi-enclosed coastal areas using fuzzy integrated assessment method (FIAM). With this method, the hierarchy structure was clarified by an index system of 11 indicators selected from biotic elements and physicochemical elements, and the weight vector of index system was calculated with Delphi-Analytic Hierarchy Process (AHP) procedure. Then, the FIAM was used to achieve an EcoQS assessment. As a result of assessment, most of the sampling stations demonstrated a clear gradient in EcoQS, ranging from high to poor status. Among the four statuses, high and good, owning a ratio of 55.9% and 26.5%, respectively, were two dominant statuses for three bays, especially for Sansha Bay and Luoyuan Bay. The assessment results were found consistent with the pressure information and parameters obtained at most stations. In addition, the sources of uncertainty in classification of EcoQS were also discussed.
اظهر المزيد [+] اقل [-]Ragworm fatty acid profiles reveals habitat and trophic interactions with halophytes and with mercury
2012
Lillebø, Ana Isabel | Cleary, Daniel Francis Richard | Marques, Bruna | Reis, Alberto | Lopes da Silva, Teresa | Calado, Ricardo
The present study aimed to assess if ragworm fatty acids (FA) profiles could be used to discriminate their spatial distribution in an historically mercury-contaminated estuarine environment, i.e., if it was possible to differentiate ragworms present in salt marsh sediments surrounding plant roots and rhizomes (rhizosediment) from adjacent unvegetated sediment. Additionally, we also tried to determine if ragworms differed in mercury content and if these values could also be used to identify the habitat they occur in. Results show that, within the same area, ragworms can be distinguished using FA profiles and that in halophyte rhizosediment ragworms display more than twice the levels of alpha-linolenic acid (18:3n-3). The ratio cis-vaccenic/oleic acids (18:1n-7/18:ln-9) in ragworms suggests higher carnivory in unvegetated sediments. Our study indicates that ragworm FA profiles can be used to identify their habitat, their trophic interaction with halophytes and reveal a spatially contrasting feeding behaviour, which also reflects mercury accumulation.
اظهر المزيد [+] اقل [-]Sedimentary records of metal contamination and eutrophication in Jinhae-Masan Bay, Korea
2012
Lim, Dhong-il | Jung, Hoi Soo | Kim, Kyung Tae | Shin, Hyeon Ho | Jung, Seung Won
Historical environmental pollution in a semi-enclosed coastal bay was investigated using high-resolution sedimentary records for Cₒᵣg, Nₜₒₜ, CaCO₃, δ¹³C, and δ¹⁵N signatures, and trace metals. A temporal increase in organic matter might have been attributable to enhanced primary marine productivity, presumably caused by increased anthropogenic nutrient inputs in the semi-enclosed, eutrophic system. Metal accumulation occurred in three stages: a preindustrial stage before the 1930s with natural concentrations of metals, an industrialization stage (1940s–1970s) with the highest concentrations, and a postindustrial stage (post 1970s) with stable or decreasing concentrations. However, Hg exhibited a different accumulation history, with concentrations increasing in the early 1900s and accelerating after the 1920s, probably in response to coal burning.
اظهر المزيد [+] اقل [-]Persistent organic pollutants in the endangered Hawaiian monk seal (Monachus schauinslandi) from the main Hawaiian Islands
2012
Bohlander, Jessica | Boyd, Daryle | Ylitalo, Gina M. | Littnan, Charles | Pearce, R. (Ronald)
Little is known about levels or effects of persistent organic pollutants (POPs) in Hawaiian monk seals (HMS) from the main Hawaiian Islands (MHI) subpopulation. This study examined concentrations of a large suite of POPs in blubber and serum of juvenile and adult HMS from the MHI. Adult females have the lowest blubber levels of most POPs, whereas adult males have highest levels. POPs in serum were significantly different in adult males compared with adult females for chlordanes and summed dichlorodiphenyltrichloroethanes (DDTs). Lipid-normalized concentrations of chlordanes, DDTs, polychlorinated biphenyls, and mirex in paired blubber and serum samples were significantly correlated. Contaminant levels from the MHI were at similar or lower levels than those from remote Northwestern Hawaiian Island populations. Determining initial ranges of POPs is an important step towards assessing one of the many potential health threats to this critically endangered species.
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