Samples biota

The identification of PCB residues in fish, wildlife, and human tissues has been reported since the 1970s (9—13,20—26). The results of these analytical studies led to the ultimate ban on further use and production of these compounds. The precise composition of PCB extracts from biota samples is highly variable and depends, in part, on the specific analyte and the commercial PCB preparations associated with a contaminated area (14). PCBs found in a composite human milk sample from Michigan (26) were highly complex, and the congener composition and their relative concentrations did not resemble any of the commercial PCB preparations. This fact raises obvious problems with regard to the ha2ard assessment of PCB mixtures (27). 

As explained in Section 5.2.3, p,p -DDE is much more persistent in food chains than either p,p -DDT or p,p -DDD, and dnring the 1960s when DDT was still extensively used, it was often the most abundant of the three compounds in birds and mammals found or sampled in the field. Since the widespread banning of DDT, very little of the pesticides has been released into the environment, and p,p -DDE is by far the most abnndant DDT residue found in biota. While discussing the ecological effects of DDT and related compounds, effects on population numbers will be considered before those on popnlation genetics (gene frequencies). 

Results from an Analytical Study of Residues in Biota Sampled from Clear Lake, California... 

The occurrence of C and C9 dicarboxylic acids in samples of atmospheric particles and in recent sediments (Stephanou 1992 Stephanou and Stratigakis 1993) has been attributed to photochemical degradation of unsaturated carboxylic acids that are widespread in almost all biota. 

Comprehensive chemical analyses of samples of water, sediment, and biota were carried out both before and after the spill. This cannot of course be carried out in most cases, and illustrates a serious limitation in field studies, in which lack of background data or difficulty in finding an uncontaminated control locality is frequently encountered. Sum parameters were sparingly employed in Baffin Island Oil Spill (BIOS), and emphasis was placed on the analysis of specific compounds attention was directed not only to PAHs, but also to azaarenes, dibenzothiophenes, and hopanes. Thereby, a clear distinction could be made between the input from the oil deliberately discharged, and that arising from natural biological reactions or mediated by atmospheric transport. 

The need for coordinated monitoring studies spanning several environmental compartments through time and space, and the need for cormnon sampling and analytical protocols this is particularly important when striving to establish links between mercury emissions and methylmercury levels in biota... 

Kamman NC, Lorey PM, Driscoll CT, Estabrook R, Major A, Pientka B, Glassford E. 2003. Assessment of mercury in waters, sediments, and biota of New Hampshire and Vermont lakes, USA, sampled using a geographically randomized design. Environ Toxicol Chem 23 1172-1186. 

Shi T, Chen SJ, Luo XJ, Zhang XL, Tang CM, Luo Y, Ma YJ, Wu JP, Peng XZ, Mai BX (2009) Occurrence of brominated flame retardants other than polybrominated diphenyl ethers in environmental and biota samples from southern China Chemosphere 74(7) 910-916. doi 10.1016/j. chemosphere.2008.10.047... 

BFRs are one of the last classes of halogenated compounds that are still being produced worldwide and used in high quantities in many applications. In order to meet fire safety regulations, flame retardants (FRs) are applied to combustible materials such as polymers, plastics, wood, paper, and textiles. Approximately 25% of all FRs contain bromine as the active ingredient. More than 80 different aliphatic, cyclo-aliphatic, aromatic, and polymeric compounds are used as BFRs. BFRs, such as polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA), have been used in different consumer products in large quantities, and consequently they were detected in the environment, biota, and even in human samples [26, 27]. 

The sampling sites are distributed along the entire basin but focusing the areas potentially polluted because of the emission of contaminant substances. Starting from 1992, the sampling sites have been extended, the list of compounds and the studied matrixes included in the network have been enlarged. Nowadays, the RCSP consists of the analysis of different compounds in water, sediments and biota from... 

Barcelo D, Porte C, Cid J, Albaiges J (1990) Determination of organophosphorus compounds in Mediterranean coastal waters and biota samples using gas-chromatography with nitrogen-phosphorus and chemical ionization mass-spectrometric detection. Int J Environ Anal Chem 38(2) 199-209... 

Similar to other POPs, BFRs (except TBBPA) appear to be lipophilic and bioaccumulate in biota and humans [5], A considerable number of studies of PBDEs in wildlife have been undertaken since the mid-1980s, when Jansson et al. [6] first indicated that these compounds were present in samples collected remote from local sources and so may have become ubiquitous environmental contaminants [7, 8]. 

There is some discussion of how bioavailable and bioaccumulative BDE-209 is. Moreover, there is still a concern that BDE-209 may debrominate in the environment to form less-brominated BDE congeners which are more bioavailable than BDE-209 itself. A preliminary study on uptake and debromination of BDE-209 in caged rainbow trout following dietary exposure [9] showed a slow but measurable uptake of BDE-209 and the presence of lower brominated PBDEs. BDE-209 has been found generally linked to sediments, but some recent studies also reported low levels of this compound in aquatic biota samples from some locations in Europe [10-12] and from Japan [13]. 

Table 3 Results (expressed in ng/g dw and ng/g ww for sediment and biota samples, respectively) obtained for samples collected along the Cinca river... 

Table 3 shows the mean concentrations of BDE congeners, as well as of HBCD, in the selected sites. PBDEs were detected in all the biota samples at concentrations ranging from 0.2 to 555 ng/g ww. HBCD was detected only in samples corresponding to sites downstream Monzon. In these samples, HBCD contamination was similar or greater than that observed for PBDEs. HBCD levels ranged from 90 to 4,863 ng/g ww. Similar to our findings in sediment samples, site C3 was found to be the most contaminated zone followed by site C5 > site Cl = site C2 [28, 33],... 

An isomeric analysis was carried out for these barbel samples. For site C5, the proportion of the y- isomer was between 96 and 98% whereas ot-isomer accounted for 2-3% and (3-isomer for 0.4%. On the other hand, in barbel not exposed and those from site C2, the predominance of the y-isomer dilutes. In fact, such profile is unusual in biological samples as reviewed by Covaci et al. [17], biota shows a higher percentage of a-HBCD than (3- or y-HBCD. The data obtained in our study could be due to a recent technical HBCD exposition. 

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