First data of the PAHs along a sediment core from Ria de Vigo

Abstract

Sediment cores can inform about the temporal trend of pollutants in an environment. Different sediment layers, settled at different times represent the pollution in that moment. A sediment core in the inner part of the Ría de Vigo was collected and some layers analysed in order to determine the temporal trend of PAHs in the last decades.

PAHs can have a natural (biogenic) and anthropogenic origin but generally the last one is the predominant. The main sources of PAHs to the environment are petroleum and coal combustions as well as fires or even the use of pitch or other petroleum products. In this study 35 individual PAHs were analysed (including parent and alkylated ones) as well as some groups of alkylated PAHs. A QA/QC is put in place to guarantee the quality of the analysis-

The sum of 16 EPA PAHs was in the range of 200-1000 µg/kg d.w. with a clear increase in the values in the more recent layers pointing at the anthropogenic activity as one of the main drivers of the PAH concentrations in sediments. The values are in the range of other estuarine areas with values above the reference values (background) but generally below the ERL and so not expected to be causing adverse biological effects. The study of the isomeric ratios of PAHs show that the origin has not changed during the period studied and it is mainly petroleum combustion mixed with different types of combustion.