Assessment of the contamination by carbonaceous anthropogenic particulates and polycyclic aromatic hydrocarbons (PAHs) concentration in recreational areas of an estuary heavily industrialized in Northern Spain

The commercial management of coal and its by-products has the potential to negatively impact natural coastal environments. The coal conversion processes and coke production are sources of polycyclic aromatic hydrocarbons (PAHs) emissions that also contribute to the pollution of those aquatic environments. This research assesses the contamination by carbonaceous anthropogenic particles and by polycyclic aromatic hydrocarbons of some recreational sites (Arano<acute accent>n, Pena del Caballo and San Balandra<acute accent>n area) located in the Avile<acute accent>s' estuary, an area in Northern Spain that has been heavily industrialized since the 1950s. The results obtained indicate a low concentration of solid organic anthropogenic particles in the intertidal sediments of the recreational sites in the estuary, probably due to the protective measures set in place at the facilities managing bulk coal and coke, which prevents the dispersion of coal dust (and other materials) as well as the eventual failure into the estuary. The characteristics of 16 priority pollutants PAHs analyzed in two recreational sites of the estuary (San Balandra<acute accent>n area), their distribution by aromatic ring number together with their diagnostic ratios demonstrate a pyrogenic nature with a main source from processes of coal and coke conversion (including combustion) in the facilities around the estuary. Some contribution of PAHs derived from petroleum cannot be ruled out. This contamination by PAHS is constant and sustained over time. The majority of the considered PAHs are well above the Spanish Generic Reference Level, (GRL) established for "protection of ecosystems with aquatic organisms", and only a few of them are notably above the corresponding Spanish GRL established for "other uses of land", which should include lands for recreational activities. The analysis of the potential toxicity risk of PAHs for human health and the organisms of the aquatic ecosystem suggests a relatively low toxicity risk to very high toxicity risk in the San Balandra<acute accent>n environment according to the concentration and distribution trend of PAHs identified in this area. This trend is dependent on the coastal dynamics and the protection level of the site, which also affect the distribution of the anthropogenic carbonaceous particulates in the same way.