Barbells

Raldua D, Ferrando P, Duran C, Pedrocchi C (1997) The influence of place of capture, sex, and season on the organochlorine pesticide content in barbel (Barbus graellsi) from Northeastern Spain. Chemosphere 35(10) 2245-2254... 

Barbel Barbus graellsii bBleak Alburnus alburnus Southwestern nase Chondrostoma toxostoma dCarp Cyprinus carpio... 

Additionally, an in situ experiment was performed to evaluate HBCD bioaccumulation. In site C5, clean barbels were exposed to the environment. As a control, the same experiment was performed in site C2. Twenty specimens of barbel were caged into each one of two stainless steel devices that were placed on the river-bed at the two locations. Nine specimens were immediately frozen to be analyzed as blanks. After 15 days of exposure, no mortality was observed in the cages. Table 4 shows levels of HBCD accumulated in the caged barbels exposed in sites C2 and C5. Accumulation at site C2 was negligible, as values measured after the exposure were even lower than those of the fishes not exposed. However, at site C5, after the... 

Fig. 2 Length of Cinca river barbel (sites C3 and C5) vs. concentrations of HBCD in the muscle. Line is linear regression on the data...

Table 4 Results (mean value (expressed in ng/g lw) standard deviation) for caged barbels exposed to an in situ bioaccumulation experiment...

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. 

First, a brief explanation of the current knowledge regarding the sources and cycling of Hg and its transformation into MeHg is presented. Later, in this chapter, THg and limited data on organomercury levels in aquatic organisms of the Ebro River basin are detailed. The aquatic organisms most commonly studied in the Ebro River basin are zebra mussel, red swamp crayfish, and different fish species, namely European catfish, northern pike, common carp, rudd, roach, barbell, and bleak. 

Barbel (Barbus graellsii), a cyprinid species endemic to the Ebro River [63], is a bottom-feeding fish. Finally, the cyprinid fish, Alburnus alburnus, also known as bleak, feed mainly on plankton, including crustaceans and insects (http //www. fishbase.org). 

Northern pike (1.93 pg/g) exhibited a significantly higher mean mercury concentration than common carp (1.23 pg/g). This result indicates a biomagnification of mercury from common carp, a larger secondary consumer, to northern pike, a tertiary consumer. Nevertheless, barbel (1.98 pg/g), also a secondary consumer, showed a mean THg level similar to that of northern pike. Different behavioral habits may explain the high mercury levels found in barbel species. 

Another well-documented case of feral fish chronically exposed to mercury through the effluent of the chlor-alkali plant is the case of the Cinca tributary [64, 65]. Barbel and bleak were collected upstream (SI) and downstream (S2) a chlor-alkali plant located at Monzon (Fig. 3). It is important to point out that there is no physical barrier between SI and S2 to prevent fish upstream migration of suspicious contaminated fishes from S2. 

Hence, the low THg levels reported in both barbel and bleak specimens sampled upstream the chlor-alkali plant in Monzon, suggest that neither of these fish species migrate upstream the factory, and therefore the fishing area upstream from Monzon does not carry a very high risk to public health, at least for these two fish species studied. 

There are several species of fish and other aquatic organisms susceptible of being used as pollution sentinels in the Ebro River (Table Species). However, none of them is present in all sites shown in Fig. 1, at least in enough abundance. From Barbastro to Flix (including the Riba-roja dam), barbel and bleak were preferred for chemical and pollution marker analyses whereas carp (Cyprinus carpio), European catfish (Silurus glanis), and roach (Rutilus rutilus) were the main species sampled in... 

This area was the most profusely studied in the AQUATERRA project in terms of biological effects in fish populations. Barbel and bleak were the sentinel species selected in this area and an array of histological and biochemical tests were used to monitor the impact due to three major sources of pollution mercury and OCs at Monzon (with a comparison in one of the papers with Flix) and PBDEs in Barbastro [1—4, 37]. Mercury pollution was directly correlated to an increase of MTprotein in the liver of barbel captured downstream Monzon when compared to samples captured upstream (Fig. 3a). However, mRNA quantitative analyses failed to show any differences between downstream and upstream Monzon, neither correlated with MT protein levels. Further studies showed that MT mRNA in liver is a rather weak marker for chronic metal pollution in liver (see below) [4], The presence of degenerative hepatocytes in barbels and bleaks was also linked to mercury poisoning although it can also reflect the impact by other pollutants, like OCs or PBDEs (Fig. 3e). 

Raldua D, Padros F, Sole M, Eljarrat E, Barcelo D, Riva MC, Barata C (2008) First evidence of polybrominated diphenyl ether (flame retardants) effects in feral barbel from the Ebro River basin (NE, Spain). Chemosphere 73(l) 56-64... 

Several AT studies [56, 57, 60, 61] have analysed PBDE and HBCD concentrations in fish (barbel, bleak and others) upstream and downstream of industrialised areas in the Ebro. These studies found high values of PBDE and HBCD in fish and sediment downstream of industrialised towns (e.g. Monzon, a heavily industrialised town draining into the river Cinca, and the Barbastro industrial site on the... 

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