Revisiting pollution data at the Bahia Blanca estuary Argentina: new insights and trends

ANDRÉS HUGO ARIAS; OLIVA ANA LAURA; PAMELA Y. QUINTAS; MARCOVECCHIO JORGE E.

Punta del Este

Congreso; XV Congreso Latinoamericano de Ciencias del Mar; 2013

Counted among POPs, Polycyclic Aromatic Hydrocarbons (PAHs) are a family of numerous hydrophobic hydrocarbons characterized by high persistence, bioaccumulative potential and toxicity properties due to their lipophilicity and widespread distribution in the environment. PAHs stick strongly to soil and sediments and will not usually be carried deep into them with rainwater or vertical infiltration water flux. As they do not readily break down, they may stay in these matrices for months or years. To test the occurrence of these COPs at the area of study, a total of 70 samples were collected over twelve selected locations, including harbours, the estuary?s main navigation channel and several industrialized coastal locations, at several sampling legs between 2004 and 2009. After Soxhlet extraction of samples, PAHs concentrations were measured through Capillary Gas Chromatography (Hewlett-Packard P68906C)/Mass Spectrometry (HP 5972). All sediment samples contained detectable amounts of PAHs. Total PAHs ranged from less than 10 ppb to more than 19000 ppb (in dry weight basis). The overall mean Total PAHs (sum of sixteen congeners) recorded in this survey was 2980 ± 4324 ppb. It is not clear whether the estuary tributaries and industries runoff transport PAHs and deposits them in sediments or that the atmosphere transports them. The molecular index analysis showed a mixed predominance of petrogenic and pyrolitics inputs with a favoring imbalance for combustion sources. In general, inputs were signed by a high temporal and compositional variability following an increasing concentration trend. In regards to pollution levels, punctual sites could be classified from moderate to high polluted environments.