Marine tissue sample analysis

Numerous high pressure Hquid chromatographic techniques have been reported for specific sample forms vegetable oHs (55,56), animal feeds (57,58), seta (59,60), plasma (61,62), foods (63,64), and tissues (63). Some of the methods requite a saponification step to remove fats, to release tocopherols from ceHs, and/or to free tocopherols from their esters. AH requite an extraction step to remove the tocopherols from the sample matrix. The methods include both normal and reverse-phase hplc with either uv absorbance or fluorescence detection. AppHcation of supercritical fluid (qv) chromatography has been reported for analysis of tocopherols in marine oHs (65). 

Techniques for analysis of different mercury species in biological samples and abiotic materials include atomic absorption, cold vapor atomic fluorescence spectrometry, gas-liquid chromatography with electron capture detection, and inductively coupled plasma mass spectrometry (Lansens etal. 1991 Schintu etal. 1992 Porcella etal. 1995). Methylmercury concentrations in marine biological tissues are detected at concentrations as low as 10 pg Hg/kg tissue using graphite furnace sample preparation techniques and atomic absorption spectrometry (Schintu et al. 1992). 

In order to reconstruct human diet from bone tissue, direct isotopic analysis of animal and plant remains from the same archaeological context is the most reliable way to detect isotopic shifts involving the whole ecosystem due to environmental variation. Since this is often impossible for the lack of these control samples, we have explored the use of 8I80 to assess the environmentally induced variation in 8I3C and 8ISN values from collagen and apatite, and assess the dietary information they represent. This can be done assuming a scarce nutritional role of marine resources and the absence of C4 crops, as seems to be the case in the western Mediterranean and specifically in the Sardinian Neolithic and Bronze Age. 

Pentachlorinated biphenyls and hexachlorinated biphenyls are the major PCB groups typically found in P. viridis. PCBs are sold commercially as technical mixtures, called Aroclors, each with a specific pattern of chlorination. Patterns have been determined for Aroclor mixtures 1221, 1232, 1242, 1248, 1254, 1260 and 1262 (Frame et al., 1996). Principal component analysis (PCA) was performed to compare the relative PCB congener profile of mussel tissues analysed in 2002 and the commercial Aroclor mixtures (Fig. 15.14). The closest match in the PCB data for P. viridis samples collected in Singapore from our study is the common Aroclor 1254. The slight discrepancy is due to the presence of PCB-149 in mussel tissue and a greater prominence of PCB-110 and -118 in Aroclor 1254. PCA analysis revealed that samples from the west Straits of Johore (Wl, W2 and W3) contain more penta-CBs and less hexa-CBs than samples from the east Straits (E6, E7 and E8). The sample collected in the south of Singapore (S4) has an intermediary pattern of PCB contamination. A similar match has been observed in marine crabs and fishes... 

The infrared identification method was used for 19 fish samples containing 12 chlorinated insecticides, alone or in combination. Two samples were collected at the site of a large fish-kill two others were controls from a reputedly uncontaminated source. A total of 14 samples consisted of fish exposed to insecticides in the water of an aquarium at a constant concentration (p.p.b. level) or dosed by oral ingestion once daily (p.p.m. level). Muscle tissue and viscera of the various fish samples were processed separately. The last sample was a can of California mackerel, packed in water and purchased at a local market (to serve as an example of marine fish). This sample contained both DDE and DDD DDE was identified by infrared analysis in the small amount of oil separated in the container. 

Fish bioaccmnulation and biomarkers in environmental risk assessment have been reviewed by Oost et al. [360]. Fish bioaccmnulation markers may be applied in order to elucidate the aquatic behavior of enviromnental contaminants and to assess exposme of aquatic organisms. The feasibility of PAH tissue concentrations in marine species as a monitoring parameter for PAH exposme depends on their uptake, biotransformation and excretion rates. Since it remains hard to accmately predict bioaccumulation in marine species, even with highly sophisticated models, analyses of tissue levels are required. The main problem is that PAHs do not tend to accumulate in fish tissues in quantities that reflect the exposme. The analysis of PAH metabolite levels in fish bile can be used to assess the actual PAH uptake, rather than the analysis of the non-hydroxylated PAHs content [328,361]. A number of sentinel fish species have been proposed to asses pollution by PAHs [325,326], as well as several mussels [322,323,326,352]. Several studies have also correlated the high levels of 1-OHPy and B(a)Py metabolites found in the bile of cat-shark with contamination sources such as boat traffic and combustion-based industries present in the sampling area [362]. 

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