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Field experiments on remediation of coastal sediments using granulated coal ash Texte intégral
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.
Afficher plus [+] Moins [-]Occurrence and distribution of phthalate esters in riverine sediments from the Pearl River Delta region, South China Texte intégral
2014
Liu, Hong | Cui, Kunyan | Zeng, Feng | Chen, Lixuan | Cheng, Yating | Li, Huiru | Li, Shuocong | Zhou, Xi | Zhu, Fang | Ouyang, Gangfeng | Luan, Tiangang | Zeng, Zunxiang
Sixty-eight sediment samples collected from Dongjiang River, Xijiang River, Beijiang River and Zhujiang River in the Pearl River Delta (PRD) region, Southern China, were analyzed for 16 phthalate esters (PAEs). PAEs were detected in all riverine sediments analyzed, which indicate that PAEs are ubiquitous environmental contaminants. The Σ16PAEs concentrations in riverine sediments in the PRD region ranged from 0.567 to 47.3μgg−1 dry weight (dw), with the mean and median concentrations of 5.34μgg−1dw and 2.15μgg−1dw, respectively. Elevated PAEs concentrations in riverine sediments in the PRD region were found in the highly urbanized and industrialized areas. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs, with the mean and median concentrations of 1.12μgg−1dw, 0.420μgg−1dw and 3.72μgg−1dw, and 0.429μgg−1dw, 0.152μgg−1dw and 1.55μgg−1dw, respectively, and accounted for 94.2–99.7% of the Σ16PAEs concentrations. Influenced by local sources and the properties of PAEs, a gradient trend of concentrations and a fractionation of composition from more to less industrialized and urbanized areas were discovered. As compared to the results from other studies, the riverine sediments in the PRD region were severely contaminated with PAEs. Information about PAEs contamination status and its effect on the aquatic organisms in the PRD region may deserve further attention.
Afficher plus [+] Moins [-]A novel best practices approach: The MARLISCO case Texte intégral
2014
Loizidou, Xenia I. | Loizides, Michael I. | Orthodoxou, Demetra L.
Research that was undertaken to identify and evaluate best practices that can effectively minimise the amount of marine litter in European Seas is presented. Best practices were approached in a novel way that aimed to maximise the impact and added value of the FP7-funded project MARLISCO. The practices served as a tool to enhance the active participation and build capacity in key actors through the implementation of the innovative, dedicatedly-developed decision support tool, DeCyDe-4-Marlisco.This paper also presents the key ‘preference’ attributes of successful marine litter management practices and provides a snapshot of the key characteristics of the recorded best practices as a means of helping the reader, and particularly decision makers, recognise what would make their marine litter management efforts more successful.
Afficher plus [+] Moins [-]Lost opportunities: Coral recruitment does not translate to reef recovery in the Florida Keys Texte intégral
2014
van Woesik, Robert | Scott, William J. | Aronson, Richard B.
We tested the hypothesis that the poor recovery of the coral populations on reefs in the Florida Keys is related to low coral recruitment. In the summer of 2011, we deployed 240 terracotta tiles at eight study sites in a balanced design: (i) among three depths; and (ii) between fished and unfished reefs. Corals recruited to ∼40% of the deployed tiles, with more corals settling on tiles on unfished reefs than on fished reefs. The apparent effect of protection was not a consequence of different densities of herbivorous fishes, but was more likely related to local hydrography and the tendency of the no-take reserves to act as larval sinks, particularly in the lower Florida Keys. There was a mismatch between the coral taxa that recruited and the adult coral assemblages, suggesting that recruits were arriving but not surviving to contribute to coral recovery.
Afficher plus [+] Moins [-]Community-level destruction of hard corals by the sea urchin Diadema setosum Texte intégral
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.
Afficher plus [+] Moins [-]Simulations of dredged sediment spreading on a Posidonia oceanica meadow off the Ligurian coast, Northwestern Mediterranean Texte intégral
2014
Capello, M. | Cutroneo, L. | Ferranti, M.P. | Budillon, G. | Bertolotto, R.M. | Ciappa, A. | Cotroneo, Y. | Castellano, M. | Povero, P. | Tucci, S.
The sandy deposits from dredging can have negative effects on the environment such as increase in suspended solids in the water column and their consequent transport. An experimental study was conducted to characterize water masses, dynamics, and sedimentation rates on the Ligurian continental shelf (Italy), where both a sand deposit, that could be used for beach nourishment, and a nearby Posidonia oceanica meadow coexist. The environmental plan provides a mathematical simulation of the sediment-dispersion to evaluate the possible impact on the meadow. It has been calculated that the dredging could double the concentration of suspended particles, but its scheduling will preclude a sediment accumulation. All the information obtained from this work will be used to study the environmental feasibility of the sand deposit exploitation and as starting point for drawing up the monitoring plan in case of dredging.
Afficher plus [+] Moins [-]Distribution of surfactants along the estuarine area of Selangor River, Malaysia Texte intégral
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.
Afficher plus [+] Moins [-]Physiological responses of the seagrass Thalassia hemprichii (Ehrenb.) Aschers as indicators of nutrient loading Texte intégral
2014
Zhang, Jingping | Huang, Xiaoping | Jiang, Zhijian
To select appropriate bioindicators for the evaluation of the influence of nutrients from human activities in a Thalassia hemprichii meadow, environmental variables and plant performance parameters were measured in Xincun Bay, Hainan Island, South China. Nutrient concentrations in the bay decreased along a gradient from west to southeast. Moreover, the nutrients decreased with an increase in the distance from the shore on the southern side of the bay. Among the candidate indicators, the P content of the tissues closely mirrored the two nutrient loading gradients. The epiphytic algae biomass and the N content in the tissues mirrored one of the two nutrient loading trends. The leaf length, however, exhibited a significant negative correlation with the nutrient gradients. We propose that changes in the P content of T. hemprichii, followed by epiphytic algae biomass and N content of the tissues, may be the useful indicators of nutrient loading to coastal ecosystems.
Afficher plus [+] Moins [-]Particle size distributions of ultrafine combustion aerosols generated from household fuels Texte intégral
2014
Tiwari, Mahesh | Sahu, Sanjay Kumar | Bhangare, Rahul Chindhu | Yousaf, Ajmal | Pandit, Gauri Girish
In the present study, the number size distributions of aerosols generated from five commonly and widely used household fuels namely firewood, coal, dung cake, kerosene stove and LPG stove were investigated using scanning mobility particle sizer (SMPS). Important parameters of PSD such as total number concentration, geometric mean (GM) and geometric standard deviation (GSD) for tested fuels were evaluated and compared. It was found that solid biomass (firewood and dung cake) generates higher particle number concentrations then non-solid fuels i.e. kerosene and LPG stove. For all biomass fuels the number concentrations were in the order of 107 particle/cm3. The geometric mean diameter was highest for dung cake generated aerosols, while LPG and coal generated aerosol showed lower GM diameter. The geometric mean diameter varied between 48nm and 152nm for all tested fuels. The geometric standard deviation values of all tested fuels revealed that in solid biomass combustion, there was more dispersion in aerosol sizes than non-solid fuels. The number concentration emitted by LPG was found to be the lowest among all fuels and the GSD was also the lowest.
Afficher plus [+] Moins [-]Air biomonitoring of heavy metals and polycyclic aromatic hydrocarbons near a cement plant Texte intégral
2014
Baldantoni, Daniela | De Nicola, Flavia | Alfani, Anna
Biomonitoring studies, based on pollutant accumulation analyses in tree leaves, allow evaluating the impact caused by air–dispersed pollutants on ecosystems, providing useful data, complementary to those obtained by instrumental monitoring. In particular, leaves of sclerophylls present morphological characteristics, such as the presence of hairs and of a tick cuticle, making them particularly useful in bioaccumulation studies. The first aim of this research was to compare heavy metal (HM) and polycyclic aromatic hydrocarbon (PAH) leaf accumulation capabilities of two Mediterranean tree species. The second aim was to evaluate the impact of a cement plant and/or of other anthropogenic activities occurring in industrial and urban areas on HM and PAH depositions. For these purposes, holm oak (Quercus ilex L.) and olive (Olea europaea L.) leaves collected along a transect industrial–urban–remote sites in southern Italy were employed. A different accumulation degree was observed for the two species. For HMs, Q. ilex leaves had the highest concentrations. The results showed that the influence of the cement plant emissions on pollutant concentrations was substantial in the area closer to clinker production and storage with the highest Pb, Ni, V, Cr, Fe, indeno(1,2,3–c,d)pyrene, benzo(g,h,i)perylene and benzo(a)anthracene leaf concentrations. However, Q. ilex leaves showed high HM and PAH concentrations also in the urban site, in relation to vehicular traffic emissions and depositions. The comparison of the results of the present study with those from the literature indicates that the overall air quality of the studied sites is not particularly compromised, also in proximity of the cement production. The use of holm oak should be preferred in biomonitoring due to its wider distribution compared to O. europaea.
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