Fjölrit RALA - 15.06.2004, Page 132

Distribution, bioavailability and behavior of persistent organic pollutants in
Andosols: with specific reference to Iceland.
Graeme I. Paton1, C.J. Paterson1, Alan Winton1, Tinnakorn Tiensing1, Olafur Arnalds2
and Julian J.C. Dawson 1
Soil Science Group, School of Biological Sciences, Cruickshank Building, University ofAberdeen
2Agricultural Research Institute, Reykjavík, Iceland
Introduction
Higher latitude soils are known to be the repositories for a wide range of persistent organic
pollutants (POPs). Studies in Greenland, Alaska and Spitzbergen have all revealed elevated
levels of POPs. In particular, highly chlorinated PCBs, dioxins, furans, OC pesticides and, in
some studies, PAHs have been found. Iceland is quite different from the afore mentioned
environments in that the milder climate and rich soils mean that terrestrial carbon
sequestration into the biosphere and pedosphere is considerable. While Icelandic studies have
considered the impact of POPs on fishing and the marine habitat, there has been no studies of
the fate of these compound in the soil environment. Iceland, a country that has little
association with these POPs, may be vulnerable to their deposition which could impact on soil
functionality. Of even more concem is the risk that if bioavailable these POPs could be
bioaccumulated and transferred through the food chain causing significant harm both to
humans and the ecology of Iceland.
Aims and objectives
The aims of this study were to-
• Assess the concentration and distribution of POPs in Icelandic soils.
• Consider the likely source of these pollutants.
• Develop techniques to assess the relative binding behavior of POPs in Andosols.
Materials and Methods
Sampling
An intense samphng regime was developed in Iceland in September 2000. Samples were
collected from thirty four locations representing a range of soil types, topography, vegetation
and altitude. Inert sampling procedures were used to avoid cross contamination of the soils
and vegetation and the samples were taken back to Aberdeen under controlled conditions.
Anaiysis
Three different groups of compounds were analysed. Full details of analytical procedures can
be found in Strachan et al. (2002) and Dawson et al. (2004). In summary: For halogenated
compounds, a hexane extract of soil was analysed after clean-up by GC-ECD. Other non-
halogenated POPs were analysed by GC-FID using a similar extraction. ID was verified by
GC-MS and suitable intemal standards. PAH levels were measured by HPLC using a uv/vis
detector or DAD at a predefmed or scanning wavelength. Detected pollutants were compared
with library data to verify source.
Assessment of bioavailability
Exhaustive extraction methods tell us little about the behaviour of POPs in the soils. To
assess this component more readily, Andosols from Napoli and Iceland were amended with a
range of concentrations of three PAHs- naphthalene, phenanthrene and pyrene. The PAHs
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