Brachidontes rodriguezii population assessment under PAH?s pollution within Argentinean coastal environments

OVAERT JULIEN; OLIVA, ANA LAURA; QUINTAS, PAMELA.; ARIAS, ANDRÉS HUGO; JORGE E. MARCOVECCHIO

Punta del Este

Congreso; XV Congreso Latinoamericano de Ciencias del Mar; 2013

ALICMAR

The Bahia Blanca estuary, located at the Atlantic coast of Argentina, has been listed in 2012 as ?The Natural Reserve of Bahia Blanca? by The World Conservation Congress, to protect biodiversity, lands and water; however, as the process of industrialization and urbanization is stepping rapidly at the area, the potential increase in contaminant loads is a serious concern. After various contaminants surveys at the estuary, no single study has been yet performed in order to study the native mussels population assemblages vs. the surrounding pollution. To test the ability of Brachidontes rodriguezii assemblages as pollution indicators, native populations were chosen at three different sites from the Bahia Blanca estuary, Argentina, including both inner (Cuatreros and Villarino Viejo) and outer stations (Pehuenco). After quadrants sampling, the populations were assessed for size classification, density, sex rate, surrounding sediment and body burden of Polycyclic Aromatic Hydrocarbons (PAHs) as pollution markers. Soxhlet extracted samples were measured through Capillary Gas Chromatography (Hewlett-Packard P68906C)/Mass Spectrometry (HP 5972). The population structure was found to be statistically different between the three stations, with high deviations at the outer station (Pehuenco), showing 87% of small individuals (< 25mm) and absence of big ones (>35 mm). In agreement, the PAH?s body burden was found to be different between the stations, with Pehuenco mussels showing the maximum levels (2178,3 ng/g dry weight). Good correlational analyses were found between the population assemblage disruption vs. PAH?s body burden, confirming the sensitiveness of this specie to PAH?s incidence. In addition, results suggested some population variables (such as density and size distribution) as early indicators of pollution stress which could be included as variables in future monitoring programs.