Search results for "sediments"
showing 10 items of 246 documents
A chemical status predictor. A methodology based on World-Wide sediment samples.
2015
As a consequence of the limited resources of underdeveloped countries and the limited interest of the developed ones, the assessment of the chemical quality of entire water bodies around the world is a utopia in the near future. The methodology described here may serve as a first approach for the fast identification of water bodies that do not meet the good chemical status demanded by the European Water Framework Directive (WFD). It also allows estimating the natural background (or reference values of concentration) of the areas under study using a simple criterion. The starting point is the calculation the World-Wide Natural Background Levels (WWNBLs) and World-Wide Threshold Values (WWTVs…
Assessment of bioavailability and effects of chemicals due to remediation actions with caging mussels (Anodonta anatina) at a creosote-contaminated l…
2002
A study was conducted at Lake Jämsänvesi in Central Finland, to identify the potential ecotoxicological risks of the remediation operation of a creosote-/PAH-contaminated lake sediment, made by capping during the years 1998-1999. Mussels (Anodonta anatina) were deployed to the lake at the same time as the remediation operation was started in November 1998. The contaminated area (0.5 ha) was covered by a filter geotextile (polypropylene), gravel and sand (1-1.5m) which were spread out on the ice and let to sink onto the bottom of the lake when the ice melted in May 1999. The possible impacts of capping to the adjacent environment were assessed from mussels exposed and particulate material se…
Effects of aquaculture waste feeds and antibiotics on marine benthic ecosystems in the Mediterranean Sea
2022
Intensive aquaculture is an important source of organic waste and antibiotics into the marine environment. Yet, their impacts on benthic marine ecosystems are poorly understood. Here, we investigated the ecological impacts of fish feed waste alone and in combination with three different antibiotics (i.e., oxytetracycline, florfenicol and flumequine) in benthic ecosystems of the Mediterranean Sea by performing a field experiment. We assessed the fate of the antibiotics in the sediment and their accumulation in wild fauna after two weeks of exposure. Moreover, we investigated the impact of the feed waste alone and in combination with the antibiotics on sediment physico-chemical properties, on…
Distribution of fullerenes (nC60) between sediment and water in freshwaters
2014
Abstract Depending on environmental conditions, fullerenes (nC 60 ) have the potential to settle to the bottom sediments. In this study the distribution of nC 60 was investigated in the labile zone between sediment and water. Three freshwater–sediment systems representing oligohumic, mesohumic, and polyhumic lakes with varying sediment composition and structure were used to investigate the target of fullerenes. The largest portion of water suspended fullerenes was found in the sediment, but a part re-suspended relatively quickly to water-stabile particles associated with natural particles. Rapid initial re-suspending was followed by a slower one offering a continuous pathway to the water ph…
Biostimulation of in situ microbial degradation processes in organically-enriched sediments mitigates the impact of aquaculture
2019
Fish farm deposition, resulting in organic matter accumulation on bottom sediments, has been identified as among the main phenomena causing negative environmental impacts in aquaculture. An in situ bioremediation treatment was carried out in order to reduce the organic matter accumulation in the fish farm sediments by promoting the natural microbial biodegradation processes. To assess the effect of the treatment, the concentration of organic matter in the sediment and its microbial degradation, as well as the response of the benthic prokaryotic community, were investigated. The results showed a significant effect of the treatment in stimulating microbial degradation rates, and the consequen…
How building an underwater pipeline connecting Libya to Sicilian coast is affecting environment: polycyclic aromatic hydrocarbons (PAHs) in sediments…
2009
The purpose of this study was to determine the variation of concentrations and distribution of PAHs in the sediments of the Gela coastal area (Italy) caused by the construction of an underwater pipeline connecting Libya to Sicilian coast. The receiving terminal of offshore pipeline, crossing the Mediterranean Sea, 516 Km long, up to 1127 meters deep, is located in Gela (Sicily, Italy). No bibliographic data regarding hydrocarbons are available for this area. In this paper we report the results of analysis on the water and organic along PAHs.The total concentrations of 16 PAHs in the sediments, analyzed during five surveys, ranged from 2.4 to 434 microg/kg of dry weight. The highest concentr…
Heavy metals in coastal water systems. A case study from the northwestern Gulf of Thailand.
2005
A geochemical survey of the northwestern part of the Thailand Gulf (Inner Gulf) was carried out in order to define concentrations and distribution patterns of selected heavy metals (V, Cr, Co, Ni, Cu, Zn, and U) in the coastal system and estuarine area of the Mae Klong river. The results indicate the presence of two different sources of heavy metals in the studied environment and allowed us to identify a lithogenic component that significantly influences the composition of coastal waters and suspended particulate matter (SPM). Comparison of the normalized heavy metals concentrations both in the studied samples and in those reported for the Sn–W ores present in the surrounding areas suggests…
Distribution of REEs in box-core sediments offshore an industrial area in SE Sicily, Ionian Sea: Evidence of anomalous sedimentary inputs
2009
The distribution of rare earth elements and yttrium (REEs+Y) has been investigated in box-core sediments recovered from four stations in the Sicilian coastal zone seawards of Augusta, one of the most industrialized and contaminated areas in the Mediterranean region. Shale-like REE patterns and low Y/Ho ratios (close to the chondritic ratio) suggest a dominant terrigenous (geogenic) source for REE. Slight enrichment of LREE over the HREE is interpreted as due to preferential adsorptive transfer of LREE from seawater to sediment particles. Samples from offshore cores exhibit slightly positive Gd and negative Ce anomalies. It is here hypothesized that main drivers of anthropogenic Gd flux towa…
Boron and lithium behaviour in river waters under semiarid climatic conditions
2022
Boron (B) and Lithium (Li) concentrations were studied in the Platani river, one of the most important catchments of South-Central Sicily which is under semiarid climatic conditions for roughly eight months to a year. In this area, evaporites result in potential B and Li sources for surface waters. Results from river waters have measured ionic strength values between 0.1 and 4.54 M. B and Li distributions in these waters were studied in colloidal (CF, extracted by ultrafiltration from the 0.45 μm filtrate) and total dissolved (TDF) fractions and in fractions extracted from corresponding riverbed sediments, according to changes of the B/Li ratio. In river waters, CF and TDF showed very simil…
Identification of carbonaceous geosorbents for PAHs by organic petrography in river floodplain soils.
2007
Organic petrographic analysis was applied to provide direct information on carbonaceous geosorbents for PAHs in river floodplain soils. The anthropogenic OM group (primarily coal and coal-derived particles) displayed large volume amounts for all the soil samples. Distinct PAH concentrations with similar PAH distribution patterns were determined in grain size and density fractions for each sample. Two-ring PAHs had stronger correlation to organic carbon (OC) than black carbon (BC) contents, while heavier PAHs showed correlation to BC, rather than OC. In this study, we combined grain size and density separation, PAH determinations, TOC and BC measurements, and organic petrographic identificat…