Quality assurance in measuring the elemental composition of the alga Fucusvesiculosus

Algae are increasingly used for the purpose of environmental biomonitoring, for instance in the long-term program of the Federal Environmental Specime n Bank of Germany. Therefore, for the studies presented here, freeze-dried samples of Fucus vesiculosus collected from the North Sea shores were analy zed for a broad range of elements by instrumental neutron activation analys is (INAA), while inductively coupled plasma atomic emission spectrometry (I CP-AES) and mass spectrometry (ICP-MS) were carried out on digests. The ent ire analytical procedures, including held sampling, cleaning of material, s ample handling, determination of blanks and instrumental parameters, are de scribed. Certified reference materials analyzed in parallel with real sampl es and intermethod comparisons were used for assuring the accuracy of the a nalytical data. Reproducibility of INAA measurements was between 4 and 6% d epending on the element considered. Possible sources of uncertainty and var iation of the contaminant origins are discussed. Boundary conditions for th e performance of algae sampling within environmental monitoring programs an d the application of this marine bioindicator for the purpose of controllin g time-dependent and local differences in element patterns are presented.