1,721,210 research outputs found
Chemical analyses and heavy metal contamination in sediments of the Venice lagoon and toxicological implications
No full textCompost amendig capability and effects on soil salinity and heavy metal content in an open field cultivation of Eruca Sativa
No full textContamination in Mytilus galloprovincialis by chlorinated hydrocarbons (PCBs and pesticides), PAHs and heavy metals in the Lagoon of Venice
No full textVariable wavelength absorption in detecting environmentally relevant PAHs by high-performance liquid chromatography
No full textTwenty-three polycyclic aromatic hydrocarbons (PAHs) were analysed by reversed-phase high-performance liquid chromatography coupled with a variable wavelength absorption detector. Compounds not chromatographically resolved were individually quantified by using characteristic UV-VIS absorption maxima programmed over three runs during the chromatographic separation. Detection limits ranging from 0.1 to 1 ng g-1 (dry weight) were found in the analysis of sediment core extracts.Twenty-three polycyclic aromatic hydrocarbons (PAHs) were analysed by reversed-phase high-performance liquid chromatography coupled with a variable wavelength absorption detector. Compounds not chromatographically resolved were individually quantified by using characteristic UV-VIS absorption maxima programmed over three runs during the chromatographic separation. Detection limits ranging from 0.1 to 1 ng g-1 (dry weight) were found in the analysis of sediment core extracts. © 1987
Relationships between macroalgal biomass and nutrient concentrations in a hypertrophic area of the Venice Lagoon
No full textMacroalgae biomass and concentrations of nitrogen, phosphorus and chlorophyll a were determined weekly or biweekly in water and sediments, during the spring-summer of 1985 in a hypertrophic area of the lagoon of Venice. Remarkable biomass production (up to 286 g m-2 day-1, wet weight), was interrupted during three periods of anoxia, when macroalgal decomposition (rate: up to 1000 g m-2 day-1) released extraordinary amounts of nutrients. Depending on the macroalgae distribution in the water column, the nutrients released in water varied from 3·3 to 19·1 μg-at litre-1 for total inorganic nitrogen and from 1·8 to 2·7 μg-at litre-1 for reactive phosphorus. Most nutrients, however, accumulated in the surficial sediment (up to 0·640 and to 3·06 mg g-1 for P and N respectively) redoubling the amounts already stored under aerobic conditions, Phytoplankton, systematically below 5 mg m-3 as Chl. a, sharply increased up to 100 mg m-3 only after the release of nutrients in water by anaerobic macroalgal decomposition. During the algal growth periods, the N:P atomic ratio in water decreased to 0·7, suggesting that nitrogen is a growth-limiting factor. This ratio for surficial sediment was between 6·6 and 13·1, similar to that of macroalgae (8·6-12·0).Macroalgae biomass and concentrations of nitrogen, phosphorus and chlorophyll a were determined weekly or biweekly in water and sediments, during the spring-summer of 1985 in a hypertrophic area of the lagoon of Venice. Remarkable biomass production (up to 286 g m-2 day-1, wet weight), was interrupted during three periods of anoxia, when macroalgal decomposition (rate: up to 1000 g m-2 day-1) released extraordinary amounts of nutrients. Depending on the macroalgae distribution in the water column, the nutrients released in water varied from 3·3 to 19·1 μg-at litre-1 for total inorganic nitrogen and from 1·8 to 2·7 μg-at litre-1 for reactive phosphorus. Most nutrients, however, accumulated in the surficial sediment (up to 0·640 and to 3·06 mg g-1 for P and N respectively) redoubling the amounts already stored under aerobic conditions, Phytoplankton, systematically below 5 mg m-3 as Chl. a, sharply increased up to 100 mg m-3 only after the release of nutrients in water by anaerobic macroalgal decomposition. During the algal growth periods, the N:P atomic ratio in water decreased to 0·7, suggesting that nitrogen is a growth-limiting factor. This ratio for surficial sediment was between 6·6 and 13·1, similar to that of macroalgae (8·6-12·0). © 1987
Macroalgae and phytoplankton competition in the central Venice lagoon
No full textThe presence-absence of macroalgae and/or phytoplankton in some areas of the Venice lagoon and the factors controlling the prevailing of one over the other were tested by monitoring two critical sites over March-December 1990. One, Sacca Sessola [B1], was the lagoon area more densely populated by macroalgae, vice versa the other, namely Fusina [D] displayed only phytoplankton blooms. For this purpose macroalgae and phytoplankton biomass variations were studied directly in field. In addition, macroalgal biomass growth was studied by resuspending pre-determined biomass amounts into net cages placed at different depths. These semi-natural methods were not able to reproduce the real algal growth, however allowed to identify the main causes of phytoplankton blooms and macroalgal absence at Fusina
Organotin compounds in surface sediments from seaports on the Gulf of Gdansk (southern Baltic Coast)
Full text linkSediment samples were collected in two Polish ports of international significance-the Port of Gdańsk and the Port of Gdynia (Gulf of Gdańsk, Baltic Sea)-in order to assess their butyltin and phenyltin contamination; this was done in 2008, just after the total ban on using harmful organotins in antifouling paints on ships came into force. Altogether, 21 sampling stations were chosen to present a diversity of port sites: from port canals and shipyards to anchorages and dumping sites. The organic carbon content and grain size of all the sediment samples were determined, and some environmental parameters (oxygen content, salinity) were measured as well. Total concentrations of butyltin compounds in sediment samples were very different and ranged between 1 and 18,520 ng Sn g -1 d.w. Phenyltin contents were distinctly lower and ranged from below the limit of detection (most samples) to 660 ng Sn g -1 d.w. The highest concentrations of organotins were found in the shipyards, the maximum total organotin content (19,180 ng Sn g -1 d.w.) being found in the Gdańsk Ship Repair Yard 'Remontowa'. Butyltin degradation indices indicate a recent tributyltin input into the port sediments. The results obtained from this work prove that the international ban on using organotins may not be enough to protect the marine environment. It is necessary to monitor organotin contamination in ports and establish concentration limits of these compounds for the disposal of dredged material at sea. © 2011 The Author(s)
Gas chromatographic determination of organic micropollutants in samples of sewage sludge and compost: Behaviour of PCB and PAH during composting
No full textIMPATTO DEGLI INVERTEBRATI ERBIVORI SULL’ACCRESCIMENTO DI ULVA RIGIDA C.AG. IN LAGUNA DI VENEZIA
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