Oker river

All metal concentrations found were relatively low and close to the limit of quantification of the SPEs/PalmSens method. As an example, cadmium concentrations estimated by SPEs/PalmSens and ICP/MS are presented in Figure 4.2.3. Although concentrations were over estimated they were in the same order of magnitude as the ICP/MS data. Results obtained by the SPEs/PalmSens are thus semi-quantitative but can lead to a comparison of a sample from one to another. Indeed, this screening resulted in the discrimination of the Oker River from the Aller River leading to the spatial variability assessment of the system. A representative picture of... 

Figure 4.2.3 Cadmium concentrations estimated by SPEs/PalmSens device and ICP/MS on unfiltered samples collected alongside the Alter and Oker rivers...

Concentrations of HHCB (5 to 191 pg/kg) and AHTN (2 to 1399 pg/kg) in Lippe river sediments were higher than those measured in a similar study by Lach and Steffen (1997), who investigated sediments of five German rivers (Elbe, Weser, Ems, Leine and Oker river). They reported concentrations of up to 54 pg/kg and up to 3.9 pg/kg for HHCB and AHTN, respectively. In contrast to Lach and Steffen (1997) ADBI was not found in this study, but AHMI could be quantified in two sediment samples collected near the river mouth. 

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