New values to assess polycyclic aromatic hydrocarbons pollution: Proposed background concentrations in marine sediment cores from the Atlantic Spanish Coast

When dealing with environmental monitoring, background assessment values are needed to identify such concentrations of pollutants that can be assumed as natural. Background Concentration (BC) values are defined for natural compounds as the concentration of a contaminant at a "pristine" or "remote" site based on contemporary or historical data. Previously BC values exist for some polycyclic aromatic hydrocarbons (PAHs), but are under revision and do not exist for individual alkylated PAHs. Moreover, they will differ in different geological locations and should be specified geographically. Based on analytical data obtained from sediment cores from the North Atlantic Coast, this study present BC values for 35 PAHs which will increase the actual database in 10 new values for parent PAHs and, for the first time, for 13 individual alkylated compounds. Granulometric and organic matter studies were performed in the sediments to both classify the studied sediments and to assure that the derived values can be used to evaluate samples with different sedimentary characteristics. The newly presented values have been compared to reference values from different countries.