Biota sediments

In aquatic environments, organotin concentrations were elevated in sediments, biota, and surface water microlayers collected near marinas, aquaculture rearing pens, and other facilities where organotin-based antifouling paints were used. In some cases, organotin concentrations in the water... 

The biogeochemical cycling picture is designed to summarize the circulation features in various components of ecosystems such as soil, surface and ground water, bottom sediments, biota and atmosphere (Figure 1). 

Various alkyl and aryltin compounds were determined in aquatic matrices, namely sediments, biota and water by means of gas chromatographic methods. In this work, comparisons of single or dual flame photometric detectors and electron capture detectors were reported (Tolosa et al., 1991). Sample preparations included acid digestion, extraction, formation of methyl derivatives and clean-up with alumina prior to gas chromatographic analysis. With the electron capture detector, cold on-column injection of organo-tin chlorides was studied. The conclusion was that a single or dual flame photometric detector equipped with a 600 nm interference filter yielded the best performance for determinations of tin species as methyl derivatives. Detection limits for the method using flame... 

Pathways of primary concern Air, drinking water, food Also, soil, sediment, biota, surface water, sewers, groundwater... 

Bulk matrix removal aims to remove material such as lipids which can disturb final analysis. This can be performed by acid treatment of the extract or by liquid-solid chromatography. Alumina fractions of chlorophenol extracts have been purified with concentrated sulfuric acid [37,38] and it has been used to remove lipid and organic coextractives in sediment, biota, and human extracts [33,43,57,58,113,114,120,122-125]. The sulfuric acid treatment of PCDEs has been reported not to affect their recoveries [58]. 

Various sample t es (soil, sediment, biota) from different locations were analysed. In most cases commercially available reference materials were used due to their well-documented sampling conditions and wide variety of sampling sites. Furthermore, bioindicators, especially moss samples were measured. These samples were from higher-contaminated (collected by the Hungarian Nuclear Society in Chernobyl and Pripjaty) and less-contaminated (Hungary and South-France) sites. The sample types, sampling locations and dates are summarized in Table 1. 

Sorption of hydrophobic halocarbons onto suspended sediments, biota, or NOM can have complex effects on photoreaction rates and quantum efficiencies. Hydrophobic or ionic halocarbons, with their great tendency to sorb on sediments or NOM, are most likely to be affected by heterogeneous photoreactions. A flurry of publications (e.g., 30-34 and references cited therein) provided abundant experimental evidence that extremely hydrophobic pollutants (e.g., polycyclic aromatic hydrocarbons, DDT, and mirex) have a strong tendency to associate with the particulate and dissolved organic matter in water bodies. 

An overview of the distribution, bioavailability, biomagnification, fate and sources of chemical pollutants such as metals, metalloids, and radionuclides in different compartments (sediments, biota, suspended matter, water) for the whole Baltic Sea ecosystem was given by Szefer (2002). 

Detrital material resulting from the decomposition of aquatic and sediment biota comprising both lipid and proteinaceous material. 

For sediment-dwelling organisms, one important factor that determines the degree of exposure to xenobiotics in the sediment phase is the partitioning from the true sediment phase into interstitial water from which the xeno-biotic may then be accumulated by biota. Exposure of sediment biota to xenobiotics is, however, a complex process, since uptake may proceed either via particulate material or via interstitial water, or by both routes. In the equilibrium partition model the concentration of a xenobiotic in the interstitial water (Ciw) is given by the following relation ... 

Sediment/biota equilibrium partitioning. A very important aspect of the assessment of the environmental fate of chemicals is the prediction of... 

I Surveillance, i.e. source screening and preliminary site characterisation. Media sediments (biota). Methodologies normalisation for grain size (2-3) and sorptive components (4) sample drying (2-3) and digestion (2-3). Additional tools tracer substances, isotopic and congener patterns (4) (bio)accumulation on organic matrices (4) and chemometric evaluation (3). 

This sediment-biota connection is further explored in Fig. 6 which compares SCCP homologs in sediment (black bars) versus bottom feeding fish (flounder and sculpin) from the same area. Unfortunately insufficient data was available to compare MCCPs in the same samples. 

A long equilibration time in case of solid samples (e.g., soils, sediments, biota) is usually necessary to simulate as well as to make possible a natural adsorption of the spike. 

Mercury Species in the Environment Most of the mercury encountered in water/ soil/sediments/biota (all environmental media except the atmosphere) is in the form of inorganic mercuric salts and orga-nomercurics. The presence of a covalent C—Hg bond differentiates organomercurics from inorganic mercury compounds that merely associate with the organic material in the environment but do not have the C—... 

In aquatic environments, organotin concentrations were elevated in sediments, biota, and surface water microlayers collected near marinas, aquaculture rearing pens, and other facilities where organotin-based antifouling paints were used. In some cases, organotin concentrations in the water column were sufficiently high to pose a substantial risk to sensitive species. Data are limited on concentrations of organotins in environmental samples, especially in samples from terrestrial ecosystems, and this may be attributed, in part, to limitations in routine chemical analytical capabilities. 

In an aquatic environment, organic compounds transmit from water to other compartments, notably soil (sediment), biota, and air. The large mass of soil and water functions as a sink for various contaminants. The distribution characteristics of organic contaminants between soil and water are thus highly important for assessing their fate in the aquatic environment. 

Netherlands Enrichment Plant Dec 1994 No signatures of enrichment could be found in water, sediment, biota, or vegetation, but swipe samples from inside buildings showed depleted and enriched uranium particles representative of enrichment operations. 

The initial motivation to development of in situ determinations as opposed to discrete sampling and subsequent analysis has been the difficulty to obtain samples from sites such as sediments, biota or small scale water layers and interfaces. 

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