Temporal Variation of Pahs in Soils from the Biobío Region: Central Southern Chile

In this short communication we describe the temporal variation of PAHs fingerprints and burden in surface soils from coastal and central valley sites in South Central Chile, with different anthropogenic influence. PAHs were extracted with accelerated solvent extraction and measured by HPLC with fluorescence detection. Levels of ∑ 15 PAHs were relatively low in both sites ranging between 190 to 3396 ng g-1 TOC of soil, However, the fingerprints were different in both sites an increment in the total concentrations was observed (p<0.001) in summer compared to winter periods (May 2001 and January 2002). These results suggest a temporal change in the total burden of PAHs and that the sources are related to biomass and coal combustion. Keyword: PAHs, Soil. Temporal variation, Pollution, Chile e-mail: [email protected] INTRODUCTION Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment. The origins are mainly from incomplete combustion both from natural and anthropogenic sources[1]. Once PAHs are emitted into the atmosphere, they can be redistributed between the gas and particle phases, and are subsequently deposited to the terrestrial environment through dry or wet deposition. Soils are a primary sink for contaminants due to their large capacity for retaining hydrophobic chemicals [2-4]. The accumulation of PAHs in soil is a result of an increment of the deposition over the degradation factors. The increment or decrease of PAHs levels in soil results from differences between degradation and loss processes and inputs from natural or anthropogenic sources such as atmospheric deposition. Therefore, the temporal study of PAHs burden in soils could be an indicator of the pollution status of the soil compartment.In Chile only the studies of Barra et al [5]and Henriquez et [6] described PAHs levels in soils samples. The study focuses on the evaluation of temporal variation of 15 USEPA PAHs in forest soils of two sites with different anthropogenic influence and sources. These results are complementary to those described by Barra et al., [5].