Rivers sampling sites

Dixon, W., G.K. Smyth, and B. Chiswell. 1999. Optimized selection of river sampling sites. Water Res. 33 971-978. 

A well known Elbe-specific compound is tetrabutyl tin, the parent substance for the synthesis of mono- to tributyl tin compounds widely used as antifoulants, stabilizers in poly(vinyl chloride)s (PVC) and industrial as well as agricultural biocides. The origin of tetrabutyl tin in sediments and suspended particulate matter of the Elbe river can be linked to an industrial point source situated near the confluence of the Mulde and the Elbe rivers (Wilken et al. 1994, Schwarzbauer, 1997). The occurence of tetrabutyl tin not only at sample sites mainly influenced by the Elbe river (sample sites A,B and C), but also in sediments situated farer from the Elbe estuary (sample sites E,F) indicates a wide spatial distribution of Elbe-derived organic matter in the German Bight. 

The basis for assessment of river quality is valid data, but the question of data validity is secondary to the fundamental question What is the purpose of the river quality assessment activity What questions are being asked In short the means are determined by the ends. If, for example, the intent of an assessment program is to ascertain compliance with law, then a fixed interval "grab sampling program could be established at various river system sites selected on the basis of established guidelines which are consistent with the... 

Sabater et al. [3] performed chemical and planktonic analyses at 31—43 sampling sites scattered along the main course of the Ebro (Fig. 1). Twenty-five sites covered from the upper reach down to the Ebro Reservoir to the reservoirs of Flix, Mequi-nenza and Ribaroja, while the other six were downstream up to 30 km from the river mouth. Samples were collected in June and October 2005 and 2006. Other surveys were completed in 2008 and 2009. Physical, chemical, and biological analyses were performed at all sites and were later related to the phytoplankton biomass. 

Fig. 2 Planktonic chlorophyll concentration along the main course of the Ebro river during the periods 2005-2006 (a) and 2008-2009 (b). Values are means of the chlorophyll samples taken in triplicate at each sampling time and in the different sampling sites...

The multivariate statistical data analysis, using principal component analysis (PCA), of this historical data revealed three main contamination profiles. A first contamination profile was identified as mostly loaded with PAHs. A samples group which includes sampling sites R1 (Ebro river in Miranda de Ebro, La Rioja), T3 (Zadorra river in Villodas, Alava) and T9 (Arga river in Puente la Reina, Navarra), all located in the upper Ebro river basin and close to Pamplona and Vitoria cities,... 

Fig. 1 Map of the sampling sites, indicating all wastewater treatment plants (WWTP), receiving river waters located downstream each plant (indicated with an square) and other river waters considered as hot-spots (highlighted as a dot)...

On the other hand, for all bioassays, sites showing highest overall HQs were the ones located close to the most populated areas and, moreover, the ones where the river flow was lower (such as PAM and T3, located nearby the cities of Pamplona and Vitoria, respectively and T9 and Til close to Zaragoza). All these sampling sites correspond to Ebro tributaries. On the other hand, and as expected, points... 

In fact, an extensive work on mercury and organomercury levels in zebra mussels collected in several sampling sites in the Flix reservoir area has been reported [32]. The specific sampling points were located in (a) hot spot, (b) wildlife reserve located on the river bank opposite the factory, (c) the meander located immediately downstream from the dam, and (d) a reference site located 1-2 km upstream from the reservoir (Fig. 2). 

Fig. 2 Location of the lower Ebro River catchment, zebra mussel, crayfish, and fish species sampling sites in the Flix dam area. Samples were taken at several stations in the four areas (RF = control site upstream WR = wildlife reserve HS = hot spot or chlor-alkali plant, and MD = meander). Positions of dams (black bars) and overflow dams (grey bars) are indicated to illustrate the mutual isolation of aquatic organisms sampled...

Fig. 3 Map with the sampling sites in the Cinca River, upstream (SI) and downstream (S2) of the chlor-alkali plant of Monzon showing THg levels. Adapted from [65]...

Fig. 1 Map of sampling sites at the Ebro River delta (NE, Spain)...

Fig. 4 Location of sampling sites of the RCSP in the Ebro River basin...

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