The relative contribution of spatial-, sampling- and analytical variation to the PAH and PCB concentrations in Baltic Sea sediments

In the study of the distribution and dynamics of organic pollutants in aqua tic environments the sediment have traditionally played an important role. In larger water bodies the properties of a few sediment samples are often e xtrapolated to large areas and the question how representative these sample s are is often left unattended. In this study it was shown that the sedimen t properties in large accumulation areas can be relatively constant over se veral km(2). However, it is also shown that the sampling procedure introduc es significant variation, and that this variation can be reduced by pooling samples prior to chemical analysis. When different accumulation areas are to be compared for concentrations and distribution, it is recommended that several samples are taken at each location and pooled before analysis. This applies also to carbon and content of different lipids classes. Comparison s of chemical profiles also revealed that PAH profiles exhibited significan t patchiness in the sediments. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.