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Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the Nantong Coast, China Texte intégral
2017
Liu, Na | Li, Xian | Zhang, Daolai | Liu, Qiang | Xiang, Lihui | Liu, Ke | Yan, Dongyun | Li, Yue
The distribution, sources, and ecological risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Nantong coast in China were investigated. The results indicated that the total concentrations of the 16 PAHs in the surface sediments from the study area ranged from 1.4 to 87.1ngg−1 dw (mean value 19.9ngg−1 dw), which were generally low compared to the adjacent offshore area and other coastal zones around the world. The selected PAH ratios and the principal components analysis for each site showed that petroleum combustion and petrogenic pollution (mainly caused by petroleum spills) were the dominant PAHs sources in the surface sediments of the coast. The ecological risk assessment indicated that most of the individual PAHs had few negative effects in this area.
Afficher plus [+] Moins [-]Greenhouse gas emission accounting at urban level: A case study of the city of Wroclaw (Poland) Texte intégral
2017
Sówka, Izabela | Bezyk, Yaroslav
The paper analyses the building process of a GHG emissions inventory, which would likely enable more strongly cities to manage their efforts and set realistic targets for emission reduction. The work includes the determination of GHG emission estimation tools and approaches used for estimation of key sources of these emissions at the local level. The actual task is the determination of major GHG emitting sectors including the key characteristics of these emissions sources at the local level, establishing targets for emissions reductions at Wroclaw urban area, Poland. The sectoral GHG emission trends in the selected urban area including a comparison of carbon dioxide (CO2) emission level with national inventory data are presented. The total GHG emissions from Wroclaw municipality in 2013 were 7.2 percent lower than those in 1990. Energy consumption is a major contributor of emissions responsible for 63% of citywide CO2 through the consumption of electricity and district and individual heating using coal and natural gas energy sources. The proposed data structure is connected in an informative Sankey diagram for all anthropogenic GHG emissions occurred in Wroclaw municipality in 2013. In order to determine the City progress towards urban carbon neutrality, reducing emissions 25% by 2020 and 80% by 2050, as well as the future risks and impacts of GHG emissions on climate change the ‘business as usual’ final energy consumption and emission scenarios are provided.
Afficher plus [+] Moins [-]Bioremediation using Gracilaria lemaneiformis to manage the nitrogen and phosphorous balance in an integrated multi-trophic aquaculture system in Yantian Bay, China Texte intégral
2017
Wei, Zhangliang | You, Jiaguo | Wu, Hailong | Yang, Fangfang | Long, Lijuan | Liu, Qiao | Huo, Yuanzi | He, Peimin
To reduce negative environmental impacts from human aquaculture activities, the red alga Gracilaria lemaneiformis was co-cultured with the fish Pseudosciaena crocea in an integrated multi-trophic aquaculture (IMTA) system for 35d in Yantian Bay. The eutrophication index value decreased from 14.5 to 8.4 after seaweeds were co-cultured in cage farming areas, which indicated that the eutrophic water column in Yantian Bay could be mediated by IMTA. Total DIN and DIP of the tidal input and output were 9.23kg, 0.19kg and 11.08kg, and 0.27kg, respectively. Total 5.24kg of dissolved N and 0.81kg of dissolved P were released from IMTA system. These results indicate that G. lemaneiformis co-cultured in IMTA system could not completely remove all excess nutrients. In theory, at least 324.48kg of seaweed seedlings would be required to balance excess nutrients generated from fish cages.
Afficher plus [+] Moins [-]A bacterial community-based index to assess the ecological status of estuarine and coastal environments Texte intégral
2017
Aylagas, Eva | Borja, Angel | Tangherlini, Michael | Dell'Anno, Antonio | Corinaldesi, Cinzia | Michell, Craig T. | Irigoien, Xabier | Danovaro, Roberto | Rodríguez-Ezpeleta, Naiara
Biotic indices for monitoring marine ecosystems are mostly based on the analysis of benthic macroinvertebrate communities. Due to their high sensitivity to pollution and fast response to environmental changes, bacterial assemblages could complement the information provided by benthic metazoan communities as indicators of human-induced impacts, but so far, this biological component has not been well explored for this purpose. Here we performed 16S rRNA gene amplicon sequencing to analyze the bacterial assemblage composition of 51 estuarine and coastal stations characterized by different environmental conditions and human-derived pressures. Using the relative abundance of putative indicator bacterial taxa, we developed a biotic index that is significantly correlated with a sediment quality index calculated on the basis of organic and inorganic compound concentrations. This new index based on bacterial assemblage composition can be a sensitive tool for providing a fast environmental assessment and allow a more comprehensive integrative ecosystem approach for environmental management.
Afficher plus [+] Moins [-]Wet deposition fluxes of atmospheric inorganic reactive nitrogen at an urban and rural site in the Indo-Gangetic Plain Texte intégral
2017
Singh, Saumya | Sharma, Anshu | Kumar, Bablu | Kulshrestha, U.C.
Excess nitrogen deposition is a matter of concern for sensitive ecosystems. However, understanding the sources and transport of Nr species has been a challenge due to limited observations of atmospheric deposition of the key Nr species across India. In this study, wet deposition of atmospheric inorganic Nr species was investigated during the year 2013 at two regionally representative sites: Delhi (an urban site) and Jaunpur (a rural site). These sites are located in the Indo-Gangetic Plain (IGP) region, which is one of the most populated and fertile regions of India. The average NH4+ concentrations in rain water were found to be 25.4 μeql−1 and 98.5 μeql−1 at the rural and urban sites, respectively, whereas average NO3− concentrations were 12.4 μeql−1 and 28.7 μeql−1 at the rural and urban sites (respectively). The annual average wet deposition fluxes of NH4+ and NO3− at Delhi were calculated as 10.45 and 3.05 kgN ha−1 yr−1 respectively, whereas at Jaunpur the fluxes were 3.19 and 1.56 kgN ha−1 yr−1 respectively. In order to assess the Nr deposition, our estimates showed 486% increase in NO3− (from 0.52 to 3.05 kgN ha−1 yr−1) while 283% NH4+ (2.72–10.44 kgN ha−1 yr−1) between 1994 and 2013 at Delhi, clearly indicating the effect of urbanization and Land Use Land Cover (LULC) change. Reduced versus oxidized N deposition contribution was also estimated. This study provides key quantitative information to support regional nitrogen budget estimates in south Asia.
Afficher plus [+] Moins [-]The impacts of the Samarco mine tailing spill on the Rio Doce estuary, Eastern Brazil Texte intégral
2017
Gomes, Luiz Eduardo de Oliveira | Correa, Lucas Barreto | Sá, Fabian | Neto, Renato Rodrigues | Bernardino, Angelo Fraga
Over 50 million cubic meters of mining tailings were released in the Rio Doce basin after the collapse of the Fundão dam (Samarco) in November 2015. Predicting significant impacts on the Rio Doce estuary, we sampled sediments to investigate short-term impacts on the benthic assemblages and trace metal accumulation on estuarine sediments. With the arrival of the tailing plumes in the estuary, we detected a predominance of clay particles and increased trace metal concentrations of up to 5 times in some areas. The rapid sedimentation after the impact also impacted estuarine macrofaunal assemblages through loss surface-dwelling taxa. As expected, the impacts on benthic assemblages observed up to 3days after the arrival of tailings were not clearly associated with trace metal concentrations, but long-term effects need to be studied. We recommend that the high spatial variability within the estuary be considered in future impact assessment studies.
Afficher plus [+] Moins [-]Polycyclic aromatic hydrocarbons (PAHs) at the Gulf of Kutch, Gujarat, India: Occurrence, source apportionment, and toxicity of PAHs as an emerging issue Texte intégral
2017
Rajpara, Rahul K. | Dudhagara, Dushyant R. | Bhatt, Jwalant K. | Gosai, Haren B. | Dave, Bharti P.
The present study extrapolates the assessment and characterization of a barely studied region, the Gulf of Kutch, (near Jamnagar), Gujarat, India, in terms of PAH exposure, adverse effects caused by them, and various toxicological indices showing the catastrophic effects of their elevated concentrations. ΣPAH concentration in the site ranged from 118,280 to 1,099,410ngg−1 dw, with a predominance of 2–3-ring PAHs (79.09%) as compared to 4–5- and 6-ring PAHs (20.91%). The concentrations of carcinogenic PAHs were found to be between 8120 and 160,000ngg−1 dw, with a mean of 63,810ngg−1 dw, which is much higher than normal acceptable values. The toxic equivalent quotient for 6CPAHs ranged from 150.47 to 26,330ngg−1 BaPeq, encompassing 50.63% of ΣPAH toxicity. This toxicological profile of the present study site would be of paramount importance as it offers fresh information regarding the load of legacy pollutants such as PAHs and the inputs and methods to cope with their extremely high concentrations in less explored marine habitats.
Afficher plus [+] Moins [-]Spatial assessment of radiocaesium in the largest lagoon in Fukushima after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident Texte intégral
2017
Kambayashi, Shota | Zhang, Jing | Narita, Hisashi
Radionuclides deposited on land by global fallouts and nuclear power station accidents spread over coastal environments through estuarine areas connecting land to ocean. In this study, we monitored activity concentration of radiocaesium in surface sediment and re-suspended particles in Matsukawa-ura lagoon, the largest lagoon in Fukushima, after the TEPCO Fukushima Dai-ichi Nuclear Power Station accident. Radiocaesium distribution in surface sediment varied spatiotemporally and irregularly due to the effect of tidal waves. The effective half-life was significantly shorter than physical half-life, suggesting some system of radiocaesium discharge in the lagoon. Sediment trap observation revealed re-suspended particles from sediment were transported to the ocean. For these reasons, it is suggested that re-suspension of particles in the lagoon and their transportation to the ocean by the seawater exchange process are important processes of radiocaesium discharge. Moreover, our results show that seawater exchange process contributes to the dispersion of radiocaesium in the ocean.
Afficher plus [+] Moins [-]Temporal variations of VOC concentrations in Bursa atmosphere Texte intégral
2017
Yurdakul, Sema | Civan, Mihriban | Kuntasal, Öznur | Doğan, Güray | Pekey, Hakan | Tuncel, Gürdal
The levels and sources of VOCs in the atmosphere of Bursa have been investigated by measuring C2–C12 VOCs which include alkanes, alkenes, alkines, aromatics and halogenated hydrocarbons in two different campaigns. The first campaign was carried out between September 14 and November 6, 2005, and the second one between March 17 and May 10, 2006. The concentrations of 112 VOCs were detected in the collected samples. The median total concentrations of VOCs were 115 and 86 μg m−3 for the first and second campaigns, respectively. Alkanes (x− = 51.50 μg m−3) are the most abundant group in the Bursa airshed, which is followed by aromatics (x− = 49.38 μg m−3), alkenes (x− = 36.86 m-3) and halogenated compounds (x− = 13.07 μg m−3). In the present study, the VOCs showed well defined diurnal, weekday/weekend and seasonal variations. Diurnal variation of most of the measured organic compounds followed traffic rush-hours. On the other hand, some VOCs such as 1-octene, 1-nonene, 1-undecene, n-nonane, n-decane, 1,2,3-trimethylbenzene, undecane and dodecane have displayed unusual profiles that do not follow the traffic pattern during the first campaign due to asphalting operations. Moreover, the average T/B ratio obtained in the first campaign was found to be significantly higher than the second one. This relatively high difference between T/B ratios is an indication of the availability of different sources rather than the traffic. Therefore, it can be suggested that there were additional VOC sources than traffic in Bursa city center.
Afficher plus [+] Moins [-]Polymer/reduced graphene oxide functionalized sponges as superabsorbents for oil removal and recovery Texte intégral
2017
Periasamy, Arun Prakash | Wu, Wen-Ping | Ravindranath, Rini | Roy, Prathik | Lin, Guan-Lin | Zhang, Huanzong
Polyurethane dish-washing (PU-DW) sponges are functionalized sequentially with polyethylenimine (PEI) and graphene oxide (GO) to form PEI/reduced graphene oxide (RGO) PU-DW sponges. The PEI/RGO PU-DW sponge consists of PEI/RGO sheets having numerous pores, with diameters ranging from 236 to 254nm. To further enhance hydrophobicity and absorption capacity of oil, PEI/RGO PU-DW sponge is further coated with 20% phenyltrimethoxysilane (PTMOS). The PTMOS/PEI/RGO PU-DW sponge absorbs various oils within 20s, with maximum absorption capacity values of 880% and 840% for bicycle chain oil and motorcycle engine oil, respectively. The absorbed oils were released completely by squeezing or immersed in hexane. The PTMOS/PEI/RGO PU-DW sponge efficiently separates oil/water mixtures through a flowing system. Having the advantages of faster absorption rate, reusability, and low cost, the PTMOS/PEI/RGO PU-DW sponge holds great potential as a superabsorbent for efficient removal and recovery of oil spills as well as for the separation of oil/water mixtures.
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