66
River and Stream Sediments
2.5.4
Silicon
Pellenberg [187] analysed river sediment for silicone content by nitrous oxideacetylene flame atomic absorption spectrophotometry. He showed that total carbon
and total carbohydrates both correlate well with silicone content and the correlation
between sedimentary silicone and presumed sewage material is good enough to
suggest silicone as a totally synthetic, specific tracer for sewage in the aquatic environment.
2.6
Radioelements
Published work on the determination of radio elements in river sediments is reviewed
in Table 2.26.
Table 2.26
Radioelements in river sediments
Element
Pu238, 239 & 240
Np237
Cs137, Sr90
Th228, 230, 232
Rn222, Ra226
Sample workup
Analytical finish
Detection limit
Solvent extraction Alpha spectrometry
Intercomparison exercise
Ash digest with HF Beta counting
0.1 pCi 100 g-l
High resolution gamma -
spectrometry and alpha
particle spectrometry
Alpha and beta spectro- -
metry
Reference
188, 189
190
191
192
193