Refine search
Results 771-780 of 2,459
Adsorption and desorption behaviors of selected endocrine disrupting chemicals in simulated gastrointestinal fluids
2014
Fei, Ying-heng | Leung, Kenneth M.Y. | Li, Xiao-yan
An in vitro technique using simulated gastrointestinal (GI) fluids was applied to investigate the desorption of selected endocrine disrupting chemicals (EDCs), i.e. bisphenol A (BPA) and 17 α-ethinylestradiol (EE2), from the marine sediment in the digestive environment. The results show that the GI fluids suppressed chemical adsorption and greatly increased the desorption of BPA and EE2 from the sediment. Pepsin in the gastric fluid would compete for the adsorption sites with the adsorbates, and bile salts in the intestinal fluid had a solubilization effect on the chemicals. The amount of chemical release from the sediment in different fluids followed intestinal (fed)>intestinal (fasted)>gastric>saline water. During the dynamic desorption tests, 62% and 21% of sediment-bound BPA and EE2, respectively, could be released into the simulated GI fluids. The enhanced desorption of EDCs from sediment in the digestive system would make the pollutants more bioavailable in the ecosystem.
Show more [+] Less [-]Variability of the dissolved nutrient (N, P, Si) concentrations in the Bay of Annaba in relation to the inputs of the Seybouse and Mafragh estuaries
2014
Ounissi, Makhlouf | Ziouch, Omar-Ramzi | Aounallah, Ouafia
Dissolved inorganic nitrogen (DIN), phosphate (PO4) and silicic acid (Si(OH)4) loads from the Seybouse and the Mafragh estuaries into the Bay of Annaba, Algeria, were assessed at three stations of the Bay over three years. The Seybouse inputs had high levels of DIN and PO4, in contrast to the Mafragh estuary’s near-pristine inputs; Si(OH)4 levels were low in both estuaries. The DIN:PO4 molar ratios were over 30 in most samples and the Si(OH)4:DIN ratio was less than 0.5 in the Seybouse waters, but nearly balanced in the Mafragh. The specific fluxes of Si–Si(OH)4 (400–540kgSikm−2yr−1) were comparable in the two catchments, but those of DIN were several-fold higher in the Seybouse (373kgNkm−2yr−1). The inner Bay affected by the Seybouse inputs had high levels of all nutrients, while the Mafragh plume and the outer marine station were less enriched.
Show more [+] Less [-]Community-level destruction of hard corals by the sea urchin Diadema setosum
2014
Qiu, Jian-Wen | Lau, Dickey C.C. | Cheang, Chi-chiu | Chow, Wing-kuen
Sea urchins are common herbivores and bioeroders of coral ecosystems, but rarely have they been reported as corallivores. We determined the spatial pattern of hard coral damage due to corallivory and bioerosion by the sea urchin Diadema setosum Leske in Hong Kong waters. Coral damage was common at the northeastern sites, with 23.7 – 90.3% colonies being either collapsed or severely damaged with >25% tissue loss. Many genera of corals were impacted by the sea urchin but the damage was most obvious for the structure forming genus Platygyra. The percentage of severely damaged and collapsed coral had significant positive correlation with the abundance of D. setosum, which ranged from 0.01 to 5.2 individuals per coral head or 0.1 – 21.1 individuals m−2 across the study sites. Remedial management actions such as sea urchin removal are urgently needed to save these fringing coral communities.
Show more [+] Less [-]Distribution of surfactants along the estuarine area of Selangor River, Malaysia
2014
Alsalahi, Murad Ali | Latif, Mohd Talib | Ali, Masni Mohd | Magam, Sami Muhsen | Wahid, Nurul Bahiyah Abd | Khan, Md Firoz | Suratman, Suhaimi
This study aims to determine the levels of methylene blue active substances (MBAS) and ethyl violet active substances (EVAS) as anionic surfactants and of disulphine blue active substances (DBAS) as cationic surfactants in the surface microlayer (SML) around an estuarine area using colorimetric methods. The results show that the concentrations of surfactants around the estuarine area were dominated by anionic surfactants (MBAS and EVAS) with average concentrations of 0.39 and 0.51μmolL−1, respectively. There were significant between-station differences in surfactant concentrations (p<0.05) with higher concentrations found at the stations near the sea. The concentration of surfactants was higher during the rainy season than the dry season due to the influence of runoff water. Further investigation using total organic carbon (TOC) and total organic nitrogen (TON) shows that there is a significant correlation (p<0.05) between both anionic and cationic surfactants and the TON concentration.
Show more [+] Less [-]Field experiments on remediation of coastal sediments using granulated coal ash
2014
Kim, Kyunghoi | Hibino, Tadashi | Yamamoto, Tamiji | Hayakawa, Shinjiro | Mito, Yugo | Nakamoto, Kenji | Lee, In-Cheol
Field experiments were carried out to evaluate the effect of Granulated Coal Ash (GCA) on remediation of coastal sediments in terms of removing phosphates and hydrogen sulfide. Phosphate concentrations in the sediment were kept below 0.2mg/l after the application of GCA, whereas those in the control sites increased up to 1.0mg/l. The concentration of hydrogen sulfide in the sediment was maintained at almost zero in the experimental sites (GCA application sites) for over one year, whereas it ranged 0.1–2.4mgSL−1 in control sites. Meanwhile, individual number of benthos increased in the experimental sites by several orders of magnitude compared to the control sites. The major process involved in hydrogen sulfide removal by GCA was thought to be the increase in pH, which suppresses hydrogen sulfide formation. From our findings, we concluded that GCA is an effective material for remediating organically enriched coastal sediment.
Show more [+] Less [-]Distribution and transfer pattern of Polychlorinated Biphenyls (PCBs) among the selected environmental media of Ny-Ålesund, the Arctic: As a case study
2014
Zhang, Peng | Ge, Linke | Gao, Hui | Yao, Ting | Fang, Xiaodan | Zhou, Chuanguang | Na, Guangshui
Polychlorinated Biphenyls (PCBs) were analyzed in multi-environmental samples collected from Ny-Ålesund, the Arctic to explore their legacy and transfer patterns. PCBs were ubiquitously in the environmental media, within the ranges of 1.73–6.27 and 9.18–141.1pgm−3 in vapor and aerosol, 2.76–10.8, 3.09–8.32, 22.5–56.3, 35.4–51.4 and 31.8–39.6ngg−1 (dry weight) in soil, sediment, plant, bird guano and reindeer faeces, respectively. The spatial distribution patterns exhibited a general southward decline in soil and sediment from the bay entrance to the inner bay. The concentration ratios of plants to soil inferred that no distinguished selective adsorption of PCBs congeners by plants existed and PCBs were mainly attributed to the air deposition on plant surface. The fugacity ratios among vapor, aerosol and soil indicted that the equilibrium status has not been reached and the net transferring direction was air–soil.
Show more [+] Less [-]Comparison of metal accumulation in the azooxanthellate scleractinian coral (Tubastraea coccinea) from different polluted environments
2014
Chan, Isani | Hung, Jia-Jang | Peng, Shao-Hung | Tseng, Li-Chun | Ho, Tung-Yuan | Hwang, Jiang-Shiou
The response of metal accumulation in coral Tubastraea coccinea to various degrees of metal enrichment was investigated from the Yin-Yang Sea (YYS) receiving abandoned mining effluents, the Kueishan Islet (KI) hydrothermal vent field, and the nearshore area of remoted Green Island (GI). The concentrations of most dissolved metals were highest in seawater at YYS, followed by KI, and then GI, showing the effects of anthropogenic and venting inputs on metal levels. Five metals (Co, Fe, Mn, Ni, and Zn) yielded significant differences (p<0.05) among the skeleton samples. We identified similar patterns in the metal–Ca ratios, indicating that the elevated metals in skeletons was a consequence of external inputs. The coral tissues were relatively sensitive in monitoring metal accumulation, showing significant differences among three locations for Cd, Co, Cu, Fe, Pb, Ni, and Zn. Specific bioconcentration factors provided strong support for the differential metal accumulation in skeletons and tissues.
Show more [+] Less [-]Long-term seafloor monitoring at an open ocean aquaculture site in the western Gulf of Maine, USA: Development of an adaptive protocol
2014
Grizzle, R.E. | Ward, L.G. | Fredriksson, D.W. | Irish, J.D. | Langan, R. | Heinig, C.S. | Greene, J.K. | Abeels, H.A. | Peter, C.R. | Eberhardt, A.L.
The seafloor at an open ocean finfish aquaculture facility in the western Gulf of Maine, USA was monitored from 1999 to 2008 by sampling sites inside a predicted impact area modeled by oceanographic conditions and fecal and food settling characteristics, and nearby reference sites. Univariate and multivariate analyses of benthic community measures from box core samples indicated minimal or no significant differences between impact and reference areas. These findings resulted in development of an adaptive monitoring protocol involving initial low-cost methods that required more intensive and costly efforts only when negative impacts were initially indicated. The continued growth of marine aquaculture is dependent on further development of farming methods that minimize negative environmental impacts, as well as effective monitoring protocols. Adaptive monitoring protocols, such as the one described herein, coupled with mathematical modeling approaches, have the potential to provide effective protection of the environment while minimize monitoring effort and costs.
Show more [+] Less [-]Regional distribution of halogenated organophosphate flame retardants in seawater samples from three coastal cities in China
2014
Hu, Mengyang | Li, Jun | Zhang, Beibei | Cui, Qinglan | Wei, Si | Yu, Hongxia
Thirteen samples of seawater were collected from Yellow Sea and East China Sea near Qingdao, Lianyungang, and Xiamen, China. They were analyzed for halogenated organophosphorus flame retardants (OPFRs). The compounds selected for detection were Tris(2-chloroethyl) phosphate (TCEP), Tris(2-chloroisopropyl) phosphate (TCPP), Tris (1,3-dichloro-2-propyl) phosphate (TDCPP), and Tris(2,3-dibromopropyl) phosphate (TDBPP). The total concentrations ranged from 91.87 to 1392ng/L and the mean concentrations of these four chemicals were 134.44, 84.12, 109.28, and 96.70ng/L, respectively. TCEP exhibited the highest concentrations, although concentrations of TCPP and TDCPP were also fairly high in Lianyungang and Xiamen. Generally, Lianyungang was the most heavily polluted district, with very high concentrations of TCEP at LYG-2 (550.54ng/L) and LYG-4 (617.92ng/L). The main sources of halogenated OPFRs were municipal and industrial effluents of wastewater treatment plants in the nearby economic and industrial zones.
Show more [+] Less [-]Sources of particulate matter pollution in a small New Zealand city
2014
Ancelet, Travis | Davy, P. K. (Perry K.) | Trompetter, William J. | Markwitz, A. (Andreas)
The sources of PM10 in the Tahunanui airshed of Nelson, New Zealand were investigated using positive matrix factorization (PMF) on elemental data obtained from filters collected from September 2008-September 2009. Also, the source(s) of peak, non-winter PM10 concentrations that exceeded the National Environmental Standard for PM10 were investigated using PM10 and meteorological data from 2007–2012 and the PMF results. Seven PM10 sources were identified: biomass burning, motor vehicles, secondary sulfate, marine aerosol, crustal matter, protective coating activities and fertilizer. Overall, biomass burning was the dominant source contributor (35% of PM10). Analyses of PM10 concentration dependences on meteorological variables showed that peak, non-winter PM10 concentrations that occurred under moderate-to-high wind speeds from the southwest were the result of vehicular movements on unsealed roads in an industrial area. From this information, it is possible for Nelson City Council, who manages air quality at Tahunanui, to formulate mitigation strategies to reduce the impact of biomass burning and industrial vehicles on local air quality.
Show more [+] Less [-]