Search results for "Total organic Carbon"
showing 10 items of 139 documents
Effect of air pressure on the electro-Fenton process at carbon felt electrodes
2018
Abstract The effect of air pressure on electro-Fenton (PrEF process) was evaluated using two organic substances (maleic acid and Acid Orange 7) as model organic pollutants. First experiments were performed using a conventional carbon felt (CF) cathode. At room pressure, a slow removal of maleic acid was obtained, together with the generation of formic acid. Conversely, using pressurized air, the removal of maleic acid was dramatically accelerated and the formation of formic acid was not detected. The utilization of a carbon felt modified by the deposition of carbon black + PTFE mixture (MCF) and of pressurized air allowed to achieve even faster and almost total (>95%) removal of total organ…
Assessment of toxicity hazards of dredged lake sediment contaminated by creosote.
2000
In order to predict the potential toxicity hazards of sediment remediation by dredging, an experimental laboratory simulation was made by investigating seven ratios of creosote-contaminated sediment (Lake Jamsanvesi, central Finland) and artificial lake water mixtures. Sediment was suspended in water at the ratios of 1:1, 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:128 v/v. The elutriates were analysed for the acute toxicity by photoluminescence bacterial and waterflea (Daphnia magna Straus) tests. The concentrations of polycyclic aromatic hydrocarbons (PAHs) are determined by gas chromatography (GC/FID). The elutriate of ratio 1:2 was most toxic to bacteria (EC50 = 4.5%), whereas the ratio 1:4 was …
The effects of land abandonment and long-term afforestation practices on the organic carbon stock and lignin content of Mediterranean humid mountain …
2019
Afforestation is an important strategy that can decrease atmospheric carbon by sequestering carbon in biomass and soil. In Spain, an active afforestation programme was adopted in the 1950s when the soil was severely eroded after widespread abandonment of arable land. The Araguás catchment (Central Spanish Pyrenees) is a good example of this programme because it was afforested with both Pinus sylvestris L. (PS) and Pinus nigra J.F.Arnold (PN). The soil organic carbon (SOC) stock and lignin content (based on the vanillyl, syringyl and cinnamyl contents) of these afforested soils were examined and compared to those of bare soil, secondary succession and meadow soils. Both the SOC stock and lig…
Differential response of benthic microbes and meiofauna to fish-farm disturbance in coastal sediments
2001
Bacterial and meiofaunal abundance and biomass and their response to the disturbance induced by fish-farm biodeposition were investigated from March to October 1997 on a monthly basis at two stations of the Gaeta Gulf (Tyrrhenian Sea, Mediterranean Sea). The biopolymeric fraction of the organic matter was characterized by high concentrations which was similar at both fish-farming-impacted and control stations. Similarly, bacteria accounted for a small fraction of the biopolymeric organic carbon (<1%), while the contribution due to auto-fluorescent cell biomass (i.e. prokaryotic and eukaryotic cells displaying auto-fluorescence) to the total biopolymeric carbon was quantitatively negligible …
Sedimentary record of anthropogenic contaminants (trace metals and PAHs) and organic matter in a Mediterranean coastal area (Gulf of Palermo, Italy)
2009
Abstract The Gulf of Palermo (Italy, Mediterranean Sea) is a contaminated coastal environment with a relatively high influx of unregulated industrial and domestic effluents. Two sediment box-cores were collected at water depths of 100 and 712 m. Samples were analysed for trace metals (As, Cu, Hg, Mn, Ni, Pb), total polycyclic aromatic hydrocarbons (ΣPAHs), organic carbon to total nitrogen (Corg/Ntot) ratios and organic carbon and nitrogen isotopic composition (δ13Corg and δ15Ntot). At the coastal site, trace metal and ΣPAH depth profiles show a clear upcore increase, indicating increasing contamination over the recent past. Concentrations of ΣPAHs, Hg, Pb, Cu, and As appear to be potentiall…
Enzymatically hydrolyzable protein and carbohydrate sedimentary pools as indicators of the trophic state of detritus sink system: a case study in a M…
2003
In order to classify the trophic state of 'detritus sink' systems, instead of the conventional indicators based on inorganic nutrient availability and algal biomass and productivity in the water column, we utilized new biochemical descriptors based on the amount of sedimentary organic carbon and nitrogen potentially available to heterotrophic nutrition. We investigated spatial and temporal changes in microphytobenthic biomass, organic matter biochemical composition and enzymatically hydrolyzable protein and carbohydrate pools along a N-S transect in the Marsala lagoon (Mediterranean Sea, Italy) at three stations characterized by different hydrodynamic conditions and organic matter content i…
The effect of fish farming organic waste on food availability for bivalve molluscs (Gaeta Gulf, Central Tyrrhenian, MED): stable carbon isotopic anal…
2001
Stable carbon isotope (δ13C) analysis was used in a fish-farming impacted Mediterranean area (the Gulf of Gaeta, Central Tyrrhenian) to determine the predominant carbon sources available to bivalve molluscs cultivated around fish cages. Wether the organic matter generated by fish farming was taken up by the bivalve molluscs was also investigated. Stable carbon isotope values were measured in the particulate organic carbon (POC) of samples from potential organic matter sources such as fish-pelleted feed, mollusc faecal waste and bivalve flesh. The sources of organic matter affecting the study area water column and benthic communities appeared to be terrigenous-continental, autochthonous (phy…
The organic carbon derived from sewage sludge as a key parameter determining the fate of trace metals.
2007
8 pages; International audience; In a sandy agricultural soil of south-west of France, continuously cultivated with maize and amended with sewage-sludge over 20 years, the behavior of three trace metals (Cu, Pb, and Zn) was studied during the sludge applications (1974-1993) and after its cessation (1993-1998). Using the delta13C analysis, the dynamics of different sources of organic matter were followed in order to elucidate the influence of the sludge-derived organic matter on the fate of trace metals in the soil and its particle size fractions. This study revealed that sludge-derived organic matter contributed to the formation of macroaggregates through the binding of preexisting microagg…
Soil Physical Quality of Citrus Orchards Under Tillage, Herbicide, and Organic Managements
2018
Abstract Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality (SPQ). In this study, the SPQ of citrus orchards was assessed under three different soil managements, namely no-tillage using herbicides, tillage under chemical farming, and no-tillage under organic farming. Commonly used indicators, such as soil bulk density, organic carbon content, and structural stability index, were considered in conjunction with capacitive indicators estimated by the Beerkan estimation of soil transfer parameter (BEST) method. The measurements taken at the L'Alcoleja Experimental Station in Spain yielded optimal values fo…
A preliminary investigation of total organic carbon variation in influent and effluent of Isfahan (Iran) water treatment plant, urban network and Fel…
2006
In this work a series of total organic carbon (TOC) analyses were carried out to analyse the influent and the effluent of a water treatment plant providing Isfahan city in Iran. Other analyses were focused on the determination of TOC in the urban network and Fellman wells (in Isfahan and Dehaghan cities), in order to compare the water quality soon after the treatment with that of circulating water in the city network. Since it supplies water treatment plant, TOC content of Zayandehrood River was also compared with the treated water. The obtained results revealed that there were significant differences between TOC content of effluent of water treatment plant and that of the urban network (ma…