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31.
Faouzi Herzi Natacha Jean Huiyu Zhao Stéphane Mounier Hassine Hadj Mabrouk Asma Sakka Hlaili 《Chemosphere》2013
In this study, metal contamination experiments were conducted to investigate the effects of copper and cadmium on the growth of the marine toxic dinoflagellate Alexandrium catenella and on the production of dissolved organic matter (Dissolved Organic Carbon: DOC; Fluorescent Dissolved Organic Matter: FDOM). This species was exposed to increasing concentrations of Cu2+ (9.93 × 10−10–1.00 × 10−7 M) or Cd2+ (1.30 × 10−8–4.38 × 10−7 M), to simulate polluted environments. The drastic effects were observed at pCu2+ = 7.96 (Cu2+: 1.08 × 10−8 M) and pCd2+ = 7.28 (Cd2+: 5.19 × 10−8 M), where cyst formation occurred. Lower levels of Cu2+ (pCu2+ > 9.00) and Cd2+ (pCd2+ > 7.28) had no effect on growth. However, when levels of Cu2+ and Cd2+ were beyond 10−7 M, the growth was totally inhibited. The DOC released per cell (DOC/Cell) was different depending on the exposure time and the metal contamination, with higher DOC/Cell values in response to Cu2+ and Cd2+, comparatively to the control. Samples were also analyzed by 3D-fluorescence spectroscopy, using the Parallel Factor Analysis (PARAFAC) algorithm to characterize the FDOM. The PARAFAC analytical treatment revealed four components (C1, C2, C3 and C4) that could be associated with two contributions: one, related to the biological activity; the other, linked to the decomposition of organic matter. The C1 component combined a tryptophan peak and a characteristic humic substances response, and the C2 component was considered as a tryptophan protein fluorophore. The C3 and C4 components were associated to marine organic matter production. 相似文献
32.
Nizar Bel Hadj Ali Tarek Abichou Roger Green 《Journal of the Air & Waste Management Association (1995)》2020,70(4):410-424
ABSTRACTAs part of the global effort to quantify and manage anthropogenic greenhouse gas emissions, there is considerable interest in quantifying methane emissions in municipal solid waste landfills. A variety of analytical and experimental methods are currently in use for this task. In this paper, an optimization-based estimation method is employed to assess fugitive landfill methane emissions. The method combines inverse plume modeling with ambient air methane concentration measurements. Three different measurement approaches are tested and compared. The method is combined with surface emission monitoring (SEM), above ground drone emission monitoring (DEM), and downwind plume emission monitoring (DWPEM). The methodology is first trialed and validated using synthetic datasets in a hand-generated case study. A field study is also presented where SEM, DEM and DWPEM are tested and compared. Methane flux during two-days measurement campaign was estimated to be between 228 and 350 g/s depending on the type of measurements used. Compared to SEM, using unmanned aerial systems (UAS) allows for a rapid and comprehensive coverage of the site. However, as showed through this work, advancement of DEM-based methane sampling is governed by the advances that could be made in UAS-compatible measurement instrumentations. Downwind plume emission monitoring led to a smaller estimated flux compared with SEM and DEM without information about positions of major leak points in the landfill. Even though, the method is simple and rapid for landfill methane screening. Finally, the optimization-based methodology originally developed for SEM, shows promising results when it is combined with the drone-based collected data and downwind concentration measurements. The studied cases also discovered the limitations of the studied sampling strategies which is exploited to identify improvement strategies and recommendations for a more efficient assessment of fugitive landfill methane emissions.Implications: Fugitive landfill methane emission estimation is tackled in the present study. An optimization-based method combined with inverse plume modeling is employed to treat data from surface emission monitoring, drone-based emission monitoring and downwind plume emission monitoring. The study helped revealing the advantages and the limitations of the studied sampling strategies. Recommendations for an efficient assessment of landfill methane emissions are formulated. The method trialed in this study for fugitive landfill methane emission could also be appropriate for rapid screening of analogous greenhouse gas emission hotspots. 相似文献
33.
A. Sakka Hlaili B. Grami Hassine Hadj Mabrouk M. Gosselin D. Hamel 《Marine Biology》2007,151(2):767-783
Phytoplankton growth and microzooplankton grazing were investigated in the restricted Bizerte Lagoon in 2002 and 2004. The
2002 study, carried out at one station from January to October, showed significant seasonal variations in phytoplankton dynamics.
High growth rates (0.9–1.04 day−1), chlorophyll a (Chl a) concentrations (6.6–6.8 μg l−1) and carbon biomass (392–398 μg C l−1) were recorded in summer (July), when several chain-forming diatoms had intensively proliferated and dominated the carbon
biomass (74%). In 2004, four stations were studied during July, a period also characterized by the high proliferation of several
diatoms that made up 70% of the algal carbon biomass. In 2004, growth rates (0.34–0.45 day−1) and biomass of algae (2.9–5.4 μg Chl a l−1 and 209–260 μg C l−1) were low, which may be related to the lower nutrient concentrations recorded in 2004. Microzooplankton >5 μm were mainly
composed of heterotrophic dinoflagellates and ciliates. Microzooplankton biomass peaked during summer (2002 320–329, 2004
246–361 μg C l−1), in response to the enhanced phytoplankton biomass and production. The grazer biomass was dominated by ciliates (71–76%)
in July 2002 and by heterotrophic dinoflagellates (52–67%) in July 2004. Throughout the year and at different stations, microzooplankton
grazed actively on phytoplankton, removing 26–58% of the Chl a and 57-84% of the primary production. In 2002, the highest grazing impact was observed on the large algae (>10 μm) during
the period of diatom dominance. These results have a significant implication for carbon export to depth. Indeed, the recycling
of most of the diatom production by the microbial food web in the upper water column would reduce the flux of material to
the seafloor. This should be considered when modeling the carbon cycling in coastal environments and under conditions of diatom
dominance. During both studies, ciliates had higher growth rates (0.5–1.5 day−1) and a higher carbon demand (165–470 μg C l−1 day−1) than dinoflagellates (0.1–0.5 day−1, 33–290 μg C l−1 day−1). Moreover, when grazer biomass was dominated by ciliates (in July 2002), herbivory accounted for 71–80% of the C ingested
by microzooplankton while it accounted only for 14–23% when dinoflagellates dominated the grazer biomass (in July 2004). These
results suggest that, in contrast to findings from open coastal waters, ciliate species of the restricted Bizerte Lagoon were
more vigorous grazers of the large algae (diatoms) than were dinoflagellates. 相似文献
34.
Ammar J. Al-Khateeb Majed I. Al-Sari Issam A. Al-Khatib Fathi Anayah 《Environmental monitoring and assessment》2017,189(2):93
Understanding the predictors of sustainability in solid waste management (SWM) systems can significantly contribute to eliminate many waste management problems. In this paper, the sustainability elements of SWM systems of interest are (1) attitudes toward separation at the source, (2) behaviour regarding reuse and/or recycling and (3) willingness to pay for an improved service of SWM. The predictors affecting these three elements were studied in two Palestinian cities: Ramallah and Jericho. The data were collected via structured questionnaires and direct interviews with the respondents, and the analysis utilized a logistic regression model. The results showed that the place of residence and dwelling premises are the significant factors influencing attitudes toward separation at the source; the place of residence and age are the significant factors explaining behaviour regarding reuse and/or recycling; while the dwelling premises, gender, level of education and being received education on waste management are the significant factors affecting willingness to pay for an improved service of SWM. 相似文献
35.
Sofiene Tlili Jamel Jebali Mohamed Banni Zohra Haouas Ammar Mlayah Ahmed Noureddine Helal Hamadi Boussetta 《Environmental monitoring and assessment》2010,168(1-4):285-298
The aim of this study is to assess the response of a multimarker approach in common carp Cyprinus carpio sampled from three Tunisian dam lakes selected according to different environmental and ecological characteristics. Glutathione-S-transferase (GST) activity was analyzed in carp liver and used as a phase II detoxification enzyme, hepatic metallothionein content (MTs) was used as a metallic stress indicator, and cholinesterase activities were analyzed in muscle and brain and used as neurotoxicity biomarker. Micronucleus frequency test (MN) as a genotoxicity marker. GST and MT levels showed an increase in fish from the Bir Mcherga site and a decrease in Sidi Saâd site with respect to fish from Nebhana site. Results showed a strong inhibition of cholinesterase activities in fish from Bir Mcherga and Sidi Saâd sites compared to Nebhana site. Relatively high level of MN is reported specially in fish blood from the Bir Mcherga site. 相似文献
36.
River sediments are basic components of our environment. It also constitutes a major source of persistent bioaccumulative
toxic chemicals which may pose threats to ecological and human health even after contaminants are no longer released from
point and non-point sources. Therefore, the aim of this study was to investigate the mobility and the availability of metals
in sediments from different sites along the Nile River in Cairo district using sequential chemical extraction technique. The
speciation data showed that most metals were associated with organic/sulfide and residual fractions. The order of total metal
concentrations in sediment samples was found to be Fe > Mn > Zn > Ni > Cu ≥ Cr > Pb > Cd. 相似文献
37.
Al-Atta Ammar Sher Farooq Hazafa Abu Zafar Ayesha Iqbal Hafiz M. N. Karahmet Emina Lester Edward 《Environmental science and pollution research international》2022,29(41):61896-61904
Environmental Science and Pollution Research - During the past few decades, the treatment of hazardous waste and toxic phenolic compounds has become a major issue in the pharmaceutical, gas/oil,... 相似文献